High-contrast 3D image acquisition using HiLo microscopy with an electrically tunable lens

NASA Astrophysics Data System (ADS)

Philipp, Katrin; Smolarski, André; Fischer, Andreas; Koukourakis, Nektarios; Stürmer, Moritz; Wallrabe, Ulricke; Czarske, Jürgen

2016-04-01

We present a HiLo microscope with an electrically tunable lens for high-contrast three-dimensional image acquisition. HiLo microscopy combines wide field and speckled illumination images to create optically sectioned images. Additionally, the depth-of-field is not fixed, but can be adjusted between wide field and confocal-like axial resolution. We incorporate an electrically tunable lens in the HiLo microscope for axial scanning, to obtain three-dimensional data without the need of moving neither the sample nor the objective. The used adaptive lens consists of a transparent polydimethylsiloxane (PDMS) membrane into which an annular piezo bending actuator is embedded. A transparent fluid is filled between the membrane and the glass substrate. When actuated, the piezo generates a pressure in the lens which deflects the membrane and thus changes the refractive power. This technique enables a large tuning range of the refractive power between 1/f = (-24 . . . 25) 1/m. As the NA of the adaptive lens is only about 0.05, a fixed high-NA lens is included in the setup to provide high resolution. In this contribution, the scan properties and capabilities of the tunable lens in the HiLo microscope are analyzed. Eventually, exemplary measurements are presented and discussed.

Fusion of lens-free microscopy and mobile-phone microscopy images for high-color-accuracy and high-resolution pathology imaging

NASA Astrophysics Data System (ADS)

Zhang, Yibo; Wu, Yichen; Zhang, Yun; Ozcan, Aydogan

2017-03-01

Digital pathology and telepathology require imaging tools with high-throughput, high-resolution and accurate color reproduction. Lens-free on-chip microscopy based on digital in-line holography is a promising technique towards these needs, as it offers a wide field of view (FOV >20 mm2) and high resolution with a compact, low-cost and portable setup. Color imaging has been previously demonstrated by combining reconstructed images at three discrete wavelengths in the red, green and blue parts of the visible spectrum, i.e., the RGB combination method. However, this RGB combination method is subject to color distortions. To improve the color performance of lens-free microscopy for pathology imaging, here we present a wavelet-based color fusion imaging framework, termed "digital color fusion microscopy" (DCFM), which digitally fuses together a grayscale lens-free microscope image taken at a single wavelength and a low-resolution and low-magnification color-calibrated image taken by a lens-based microscope, which can simply be a mobile phone based cost-effective microscope. We show that the imaging results of an H&E stained breast cancer tissue slide with the DCFM technique come very close to a color-calibrated microscope using a 40x objective lens with 0.75 NA. Quantitative comparison showed 2-fold reduction in the mean color distance using the DCFM method compared to the RGB combination method, while also preserving the high-resolution features of the lens-free microscope. Due to the cost-effective and field-portable nature of both lens-free and mobile-phone microscopy techniques, their combination through the DCFM framework could be useful for digital pathology and telepathology applications, in low-resource and point-of-care settings.

The original method for imaging of biological tissues in optical coherence tomography with usage of hyperchromatic lens

NASA Astrophysics Data System (ADS)

Egorov, D. I.

2017-06-01

Our study focuses on an analysis of the original method of investigation biological tissues in the spectral OCT (optical coherence tomography) with usage hyperchromatic lenses. Using hyperchromatic lens, i.e. the lens with uncorrected longitudinal color allows scanning in the depth of the object by changing the wavelength of the emitter. In this case, the depth of the scan will be determined not by the microlens depth of field, but the value of axial color. In our study, we demonstrated the advantages of this method of research on biological tissues existing. Spectral OCT schemes with the hyperchromatic lens could increase the depth of spectral scanning, eliminate the use of multi-channel systems with a set of microscope objectives, reduce the time of measurement. In our paper, we show the developed method of calculation of hyperchromatic lenses and hybrid hyperchromatic lens consisting of a diffractive and refractive component in spectral OCT systems. We also demonstrate the results of aberration calculation designed microscope lenses. We show examples of developed hyperchromatic lenses with the diffractive element and without it.

Defocus and magnification dependent variation of TEM image astigmatism.

PubMed

Yan, Rui; Li, Kunpeng; Jiang, Wen

2018-01-10

Daily alignment of the microscope is a prerequisite to reaching optimal lens conditions for high resolution imaging in cryo-EM. In this study, we have investigated how image astigmatism varies with the imaging conditions (e.g. defocus, magnification). We have found that the large change of defocus/magnification between visual correction of astigmatism and subsequent data collection tasks, or during data collection, will inevitably result in undesirable astigmatism in the final images. The dependence of astigmatism on the imaging conditions varies significantly from time to time, so that it cannot be reliably compensated by pre-calibration of the microscope. Based on these findings, we recommend that the same magnification and the median defocus of the intended defocus range for final data collection are used in the objective lens astigmatism correction task during microscope alignment and in the focus mode of the iterative low-dose imaging. It is also desirable to develop a fast, accurate method that can perform dynamic correction of the astigmatism for different intended defocuses during automated imaging. Our findings also suggest that the slope of astigmatism changes caused by varying defocuses can be used as a convenient measurement of objective lens rotation symmetry and potentially an acceptance test of new electron microscopes.

Lens Systems Incorporating A Zero Power Corrector Part 3 New Four-Element Microscope Objectives With Flat Field Or High Power

NASA Astrophysics Data System (ADS)

Klee, H. W.; McDowell, M. W.

1986-02-01

The use of the zero power corrector concept has been extended to the design of microscope objectives. Several four and five-element designs are described which include a flat field 10x design of 0.25 numerical aperture and a 40x design of 0.65 numerical aperture.

Wide-field computational imaging of pathology slides using lens-free on-chip microscopy.

PubMed

Greenbaum, Alon; Zhang, Yibo; Feizi, Alborz; Chung, Ping-Luen; Luo, Wei; Kandukuri, Shivani R; Ozcan, Aydogan

2014-12-17

Optical examination of microscale features in pathology slides is one of the gold standards to diagnose disease. However, the use of conventional light microscopes is partially limited owing to their relatively high cost, bulkiness of lens-based optics, small field of view (FOV), and requirements for lateral scanning and three-dimensional (3D) focus adjustment. We illustrate the performance of a computational lens-free, holographic on-chip microscope that uses the transport-of-intensity equation, multi-height iterative phase retrieval, and rotational field transformations to perform wide-FOV imaging of pathology samples with comparable image quality to a traditional transmission lens-based microscope. The holographically reconstructed image can be digitally focused at any depth within the object FOV (after image capture) without the need for mechanical focus adjustment and is also digitally corrected for artifacts arising from uncontrolled tilting and height variations between the sample and sensor planes. Using this lens-free on-chip microscope, we successfully imaged invasive carcinoma cells within human breast sections, Papanicolaou smears revealing a high-grade squamous intraepithelial lesion, and sickle cell anemia blood smears over a FOV of 20.5 mm(2). The resulting wide-field lens-free images had sufficient image resolution and contrast for clinical evaluation, as demonstrated by a pathologist's blinded diagnosis of breast cancer tissue samples, achieving an overall accuracy of ~99%. By providing high-resolution images of large-area pathology samples with 3D digital focus adjustment, lens-free on-chip microscopy can be useful in resource-limited and point-of-care settings. Copyright © 2014, American Association for the Advancement of Science.

Three-dimensional confocal microscopy of the living cornea and ocular lens

NASA Astrophysics Data System (ADS)

Masters, Barry R.

1991-07-01

The three-dimensional reconstruction of the optic zone of the cornea and the ocular crystalline lens has been accomplished using confocal microscopy and volume rendering computer techniques. A laser scanning confocal microscope was used in the reflected light mode to obtain the two-dimensional images from the cornea and the ocular lens of a freshly enucleated rabbit eye. The light source was an argon ion laser with a 488 nm wavelength. The microscope objective was a Leitz X25, NA 0.6 water immersion lens. The 400 micron thick cornea was optically sectioned into 133 three micron sections. The semi-transparent cornea and the in-situ ocular lens was visualized as high resolution, high contrast two-dimensional images. The structures observed in the cornea include: superficial epithelial cells and their nuclei, basal epithelial cells and their 'beaded' cell borders, basal lamina, nerve plexus, nerve fibers, nuclei of stromal keratocytes, and endothelial cells. The structures observed in the in- situ ocular lens include: lens capsule, lens epithelial cells, and individual lens fibers. The three-dimensional data sets of the cornea and the ocular lens were reconstructed in the computer using volume rendering techniques. Stereo pairs were also created of the two- dimensional ocular images for visualization. The stack of two-dimensional images was reconstructed into a three-dimensional object using volume rendering techniques. This demonstration of the three-dimensional visualization of the intact, enucleated eye provides an important step toward quantitative three-dimensional morphometry of the eye. The important aspects of three-dimensional reconstruction are discussed.

FPscope: a field-portable high-resolution microscope using a cellphone lens.

PubMed

Dong, Siyuan; Guo, Kaikai; Nanda, Pariksheet; Shiradkar, Radhika; Zheng, Guoan

2014-10-01

The large consumer market has made cellphone lens modules available at low-cost and in high-quality. In a conventional cellphone camera, the lens module is used to demagnify the scene onto the image plane of the camera, where image sensor is located. In this work, we report a 3D-printed high-resolution Fourier ptychographic microscope, termed FPscope, which uses a cellphone lens in a reverse manner. In our platform, we replace the image sensor with sample specimens, and use the cellphone lens to project the magnified image to the detector. To supersede the diffraction limit of the lens module, we use an LED array to illuminate the sample from different incident angles and synthesize the acquired images using the Fourier ptychographic algorithm. As a demonstration, we use the reported platform to acquire high-resolution images of resolution target and biological specimens, with a maximum synthetic numerical aperture (NA) of 0.5. We also show that, the depth-of-focus of the reported platform is about 0.1 mm, orders of magnitude longer than that of a conventional microscope objective with a similar NA. The reported platform may enable healthcare accesses in low-resource settings. It can also be used to demonstrate the concept of computational optics for educational purposes.

DotLens smartphone microscopy for biological and biomedical applications (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sung, Yu-Lung; Zhao, Fusheng; Shih, Wei-Chuan

2017-02-01

Recent advances in inkjet-printed optics have created a new class of lens fabrication technique. Lenses with a tunable geometry, magnification, and focal length can be fabricated by dispensing controlled amounts of liquid polymer onto a heated surface. This fabrication technique is highly cost-effective, and can achieve optically smooth surface finish. Dubbed DotLens, a single of which weighs less than 50 mg and occupies a volume less than 50 μL. DotLens can be attached onto any smartphone camera akin to a contact lens, and enable smartphones to obtain image resolution as fine as 1 µm. The surface curvature modifies the optical path of light to the image sensor, and enables the camera to focus as close as 2 mm. This enables microscopic imaging on a smartphone without any additional attachments, and has shown great potential in mobile point-of-care diagnostic systems, particularly for histology of tissue sections and cytology of blood cells. DotLens Smartphone Microscopy represents an innovative approach fundamentally different from other smartphone microscopes. In this paper, we describe the application and performance of DotLens smartphone microscopy in biological and biomedical research. In particular, we show recent results from images collected from pathology tissue slides with cancer features. In addition, we show performance in cytological analysis of blood smear. This tool has empowered Citizen Science investigators to collect microscopic images from various interesting objects.

Electrically tunable lens speeds up 3D orbital tracking

PubMed Central

Annibale, Paolo; Dvornikov, Alexander; Gratton, Enrico

2015-01-01

3D orbital particle tracking is a versatile and effective microscopy technique that allows following fast moving fluorescent objects within living cells and reconstructing complex 3D shapes using laser scanning microscopes. We demonstrated notable improvements in the range, speed and accuracy of 3D orbital particle tracking by replacing commonly used piezoelectric stages with Electrically Tunable Lens (ETL) that eliminates mechanical movement of objective lenses. This allowed tracking and reconstructing shape of structures extending 500 microns in the axial direction. Using the ETL, we tracked at high speed fluorescently labeled genomic loci within the nucleus of living cells with unprecedented temporal resolution of 8ms using a 1.42NA oil-immersion objective. The presented technology is cost effective and allows easy upgrade of scanning microscopes for fast 3D orbital tracking. PMID:26114037

Wide-field synovial fluid imaging using polarized lens-free on-chip microscopy for point-of-care diagnostics of gout (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zhang, Yibo; Lee, Seung Yoon; Zhang, Yun; Furst, Daniel; Fitzgerald, John; Ozcan, Aydogan

2016-03-01

Gout and pseudogout are forms of crystal arthropathy caused by monosodium urate (MSU) and calcium pyrophosphate dehydrate (CPPD) crystals in the joint, respectively, that can result in painful joints. Detecting the unique-shaped, birefringent MSU/CPPD crystals in a synovial fluid sample using a compensated polarizing microscope has been the gold-standard for diagnosis since the 1960's. However, this can be time-consuming and inaccurate, especially if there are only few crystals in the fluid. The high-cost and bulkiness of conventional microscopes can also be limiting for point-of-care diagnosis. Lens-free on-chip microscopy based on digital holography routinely achieves high-throughput and high-resolution imaging in a cost-effective and field-portable design. Here we demonstrate, for the first time, polarized lens-free on-chip imaging of MSU and CPPD crystals over a wide field-of-view (FOV ~ 20.5 mm2, i.e., <20-fold larger compared a typical 20X objective-lens FOV) for point-of-care diagnostics of gout and pseudogout. Circularly polarizer partially-coherent light is used to illuminate the synovial fluid sample on a glass slide, after which a quarter-wave-plate and an angle-mismatched linear polarizer are used to analyze the transmitted light. Two lens-free holograms of the MSU/CPPD sample are taken, with the sample rotated by 90°, to rule out any non-birefringent objects within the specimen. A phase-recovery algorithm is also used to improve the reconstruction quality, and digital pseudo-coloring is utilized to match the color and contrast of the lens-free image to that of a gold-standard microscope image to ease the examination by a rheumatologist or a laboratory technician, and to facilitate computerized analysis.

Wide-field imaging of birefringent synovial fluid crystals using lens-free polarized microscopy for gout diagnosis

NASA Astrophysics Data System (ADS)

Zhang, Yibo; Lee, Seung Yoon Celine; Zhang, Yun; Furst, Daniel; Fitzgerald, John; Ozcan, Aydogan

2016-06-01

Gout is a form of crystal arthropathy where monosodium urate (MSU) crystals deposit and elicit inflammation in a joint. Diagnosis of gout relies on identification of MSU crystals under a compensated polarized light microscope (CPLM) in synovial fluid aspirated from the patient’s joint. The detection of MSU crystals by optical microscopy is enhanced by their birefringent properties. However, CPLM partially suffers from the high-cost and bulkiness of conventional lens-based microscopy, and its relatively small field-of-view (FOV) limits the efficiency and accuracy of gout diagnosis. Here we present a lens-free polarized microscope which adopts a novel differential and angle-mismatched polarizing optical design achieving wide-field and high-resolution holographic imaging of birefringent objects with a color contrast similar to that of a standard CPLM. The performance of this computational polarization microscope is validated by imaging MSU crystals made from a gout patient’s tophus and steroid crystals used as negative control. This lens-free polarized microscope, with its wide FOV (>20 mm2), cost-effectiveness and field-portability, can significantly improve the efficiency and accuracy of gout diagnosis, reduce costs, and can be deployed even at the point-of-care and in resource-limited clinical settings.

Wide-field imaging of birefringent synovial fluid crystals using lens-free polarized microscopy for gout diagnosis

PubMed Central

Zhang, Yibo; Lee, Seung Yoon Celine; Zhang, Yun; Furst, Daniel; Fitzgerald, John; Ozcan, Aydogan

2016-01-01

Gout is a form of crystal arthropathy where monosodium urate (MSU) crystals deposit and elicit inflammation in a joint. Diagnosis of gout relies on identification of MSU crystals under a compensated polarized light microscope (CPLM) in synovial fluid aspirated from the patient’s joint. The detection of MSU crystals by optical microscopy is enhanced by their birefringent properties. However, CPLM partially suffers from the high-cost and bulkiness of conventional lens-based microscopy, and its relatively small field-of-view (FOV) limits the efficiency and accuracy of gout diagnosis. Here we present a lens-free polarized microscope which adopts a novel differential and angle-mismatched polarizing optical design achieving wide-field and high-resolution holographic imaging of birefringent objects with a color contrast similar to that of a standard CPLM. The performance of this computational polarization microscope is validated by imaging MSU crystals made from a gout patient’s tophus and steroid crystals used as negative control. This lens-free polarized microscope, with its wide FOV (>20 mm2), cost-effectiveness and field-portability, can significantly improve the efficiency and accuracy of gout diagnosis, reduce costs, and can be deployed even at the point-of-care and in resource-limited clinical settings. PMID:27356625

Magnified hard x-ray microtomography: toward tomography with submicron resolution

NASA Astrophysics Data System (ADS)

Schroer, Christian G.; Benner, Boris; Guenzler, Til F.; Kuhlmann, Marion; Lengeler, Bruno; Rau, Christoph; Weitkamp, Timm; Snigirev, Anatoly A.; Snigireva, Irina

2002-01-01

Parabolic compound refractive lenses (PCRLs) are high quality imaging optics for hard x-rays that can be used as an objective lens in a new type of hard x-ray full field microscope. Using an aluminium PCRL, this new type of microscope has been shown to have a resolution of 350 nm. Further improvement of the resolution down to 50 nm can be expected using beryllium as a lens material. The large depth of field (several mm) of the microscope results in sharp projection images for samples that fit into the field of view of about 300 micrometers. This allows to combine magnified imaging with tomographic techniques. First results of magnified microtomography are shown. Contrast formation in the microscope and the consequences for tomographic reconstruction are discussed. An outlook on further developments is given.

Apparatus for Direct Optical Fiber Through-Lens Illumination of Microscopy or Observational Objects

NASA Technical Reports Server (NTRS)

Kadogawa, Hiroshi (Inventor)

2001-01-01

In one embodiment of the invention, a microscope or other observational apparatus, comprises a hollow tube, a lens mounted to the tube, a light source and at least one flexible optical fiber having an input end and an output end. The input end is positioned to receive light from the light source, and the output end is positioned within the tube so as to directly project light along a straight path to the lens to illuminate an object to be viewed. The path of projected light is uninterrupted and free of light deflecting elements. By passing the light through the lens, the light can be diffused or otherwise defocused to provide more uniform illumination across the surface of the object, increasing the quality of the image of the object seen by the viewer. The direct undeflected and uninterrupted projection of light, without change of direction, eliminates the need for light-deflecting elements, such as beam-splitters, mirrors, prisms, or the like, to direct the projected light towards the object.

Fiber-optic confocal reflectance microscope with miniature objective for in vivo imaging of human tissues.

PubMed

Sung, Kung-Bin; Liang, Chen; Descour, Michael; Collier, Tom; Follen, Michele; Richards-Kortum, Rebecca

2002-10-01

We have built a fiber-optic confocal reflectance microscope capable of imaging human tissues in near real time. Miniaturization of the objective lens and the mechanical components for positioning and axially scanning the objective enables the device to be used in inner organs of the human body. The lateral resolution is 2 micrometers and axial resolution is 10 micrometers. Confocal images of fixed tissue biopsies and the human lip in vivo have been obtained at 15 frames/s without any fluorescent stains. Both cell morphology and tissue architecture can be appreciated from images obtained with this microscope.

Laterally modulated excitation microscopy: improvement of resolution by using a diffraction grating

NASA Astrophysics Data System (ADS)

Heintzmann, Rainer; Cremer, Christoph G.

1999-01-01

High spatial frequencies in the illuminating light of microscopes lead to a shift of the object spatial frequencies detectable through the objective lens. If a suitable procedure is found for evaluation of the measured data, a microscopic image with a higher resolution than under flat illumination can be obtained. A simple method for generation of a laterally modulated illumination pattern is discussed here. A specially constructed diffraction grating was inserted in the illumination beam path at the conjugate object plane (position of the adjustable aperture) and projected through the objective into the object. Microscopic beads were imaged with this method and evaluated with an algorithm based on the structure of the Fourier space. The results indicate an improvement of resolution.

Design for an aberration corrected scanning electron microscope using miniature electron mirrors.

PubMed

Dohi, Hideto; Kruit, Pieter

2018-06-01

Resolution of scanning electron microscopes (SEMs) is determined by aberrations of the objective lens. It is well known that both spherical and chromatic aberrations can be compensated by placing a 90-degree bending magnet and an electron mirror in the beam path before the objective lens. Nevertheless, this approach has not led to wide use of these aberration correctors, partly because aberrations of the bending magnet can be a serious problem. A mirror corrector with two mirrors placed perpendicularly to the optic axis of an SEM and facing each other is proposed. As a result, only small-angle magnetic deflection is necessary to guide the electron beam around the top mirror to the bottom mirror and around the bottom mirror to the objective lens. The deflection angle, in the order of 50 mrad, is sufficiently small to avoid deflection aberrations. In addition, lateral dispersion at the sample plane can be avoided by making the deflection fields symmetric. Such a corrector system is only possible if the incoming beam can pass the top mirror at a distance in the order of millimeters, without being disturbed by the electric fields of electrodes of the mirror. It is proposed that condition can be satisfied with micro-scale electron optical elements fabricated by using MEMS technology. In the proposed corrector system, the micro-mirrors have to provide the exact negative spherical and chromatic aberrations for correcting the aberration of the objective lens. This exact tuning is accomplished by variable magnification between the micro-mirrors and the objective lens using an additional transfer lens. Extensive optical calculations are reported. Aberrations of the micro-mirrors were analyzed by numerical calculation. Dispersion and aberrations of the deflectors were calculated by using an analytical field model. Combination aberrations caused by the off-axis position of dispersive rays in the mirrors and objective lens were also analyzed. It is concluded that the proposed corrector system will be a promising candidate for simple and low-cost aberration correction in low-voltage SEMs. Copyright © 2018 Elsevier B.V. All rights reserved.

Three-dimensional microscope tracking system using the astigmatic lens method and a profile sensor

NASA Astrophysics Data System (ADS)

Kibata, Hiroki; Ishii, Katsuhiro

2018-03-01

We developed a three-dimensional microscope tracking system using the astigmatic lens method and a profile sensor, which provides three-dimensional position detection over a wide range at the rate of 3.2 kHz. First, we confirmed the range of target detection of the developed system, where the range of target detection was shown to be ± 90 µm in the horizontal plane and ± 9 µm in the vertical plane for a 10× objective lens. Next, we attempted to track a motion-controlled target. The developed system kept the target at the center of the field of view and in focus up to a target speed of 50 µm/s for a 20× objective lens. Finally, we tracked a freely moving target. We successfully demonstrated the tracking of a 10-µm-diameter polystyrene bead suspended in water for 40 min. The target was kept in the range of approximately 4.9 µm around the center of the field of view. In addition, the vertical direction was maintained in the range of ± 0.84 µm, which was sufficiently within the depth of focus.

Design of high-performance adaptive objective lens with large optical depth scanning range for ultrabroad near infrared microscopic imaging

PubMed Central

Lan, Gongpu; Mauger, Thomas F.; Li, Guoqiang

2015-01-01

We report on the theory and design of adaptive objective lens for ultra broadband near infrared light imaging with large dynamic optical depth scanning range by using an embedded tunable lens, which can find wide applications in deep tissue biomedical imaging systems, such as confocal microscope, optical coherence tomography (OCT), two-photon microscopy, etc., both in vivo and ex vivo. This design is based on, but not limited to, a home-made prototype of liquid-filled membrane lens with a clear aperture of 8mm and the thickness of 2.55mm ~3.18mm. It is beneficial to have an adaptive objective lens which allows an extended depth scanning range larger than the focal length zoom range, since this will keep the magnification of the whole system, numerical aperture (NA), field of view (FOV), and resolution more consistent. To achieve this goal, a systematic theory is presented, for the first time to our acknowledgment, by inserting the varifocal lens in between a front and a back solid lens group. The designed objective has a compact size (10mm-diameter and 15mm-length), ultrabroad working bandwidth (760nm - 920nm), a large depth scanning range (7.36mm in air) — 1.533 times of focal length zoom range (4.8mm in air), and a FOV around 1mm × 1mm. Diffraction-limited performance can be achieved within this ultrabroad bandwidth through all the scanning depth (the resolution is 2.22 μm - 2.81 μm, calculated at the wavelength of 800nm with the NA of 0.214 - 0.171). The chromatic focal shift value is within the depth of focus (field). The chromatic difference in distortion is nearly zero and the maximum distortion is less than 0.05%. PMID:26417508

Cornea and ocular lens visualized with three-dimensional confocal microscopy

NASA Astrophysics Data System (ADS)

Masters, Barry R.

1992-08-01

This paper demonstrates the advantages of three-dimensional reconstruction of the cornea and the ocular crystalline lens by confocal microscopy and volume rendering computer techniques. The advantages of noninvasive observation of ocular structures in living, unstained, unfixed tissue include the following: the tissue is in a natural living state without the artifacts of fixation, mechanical sectioning, and staining; the three-dimensional structure can be observed from any view point and quantitatively analyzed; the dynamics of morphological changes can be studied; and the use of confocal microscopic observation results in a reduction of the number of animals required for ocular morphometric studies. The main advantage is that the dynamic morphology of ocular structures can be investigated in living ocular tissue. A laser scanning confocal microscope was used in the reflected light mode to obtain the two- dimensional images from the cornea and the ocular lens of a freshly enucleated rabbit eye. The light source was an argon ion laser with 488 nm wavelength. The microscope objective was a Leitz 25X, NA 0.6 water immersion lens. The 400 micron thick cornea was optically sectioned into 133, three micron sections. The semi-transparent cornea and the in-situ ocular lens was visualized as high resolution, high contrast two-dimensional images. The under sampling resulted in a three-dimensional visualization rendering in which the corneal thickness (z-axis) is compressed. The structures observed in the cornea include: superficial epithelial cells and their nuclei, basal epithelial cells and their `beaded' cell borders, basal lamina, nerve plexus, nerve fibers, free nerve endings in the basal epithelial cells, nuclei of stromal keratocytes, and endothelial cells. The structures observed in the in-situ ocular lens include: lens capsule, lens epithelial cells, and individual lens fibers.

Resolution and throughput optimized intraoperative spectrally encoded coherence tomography and reflectometry (iSECTR) for multimodal imaging during ophthalmic microsurgery

NASA Astrophysics Data System (ADS)

Malone, Joseph D.; El-Haddad, Mohamed T.; Leeburg, Kelsey C.; Terrones, Benjamin D.; Tao, Yuankai K.

2018-02-01

Limited visualization of semi-transparent structures in the eye remains a critical barrier to improving clinical outcomes and developing novel surgical techniques. While increases in imaging speed has enabled intraoperative optical coherence tomography (iOCT) imaging of surgical dynamics, several critical barriers to clinical adoption remain. Specifically, these include (1) static field-of-views (FOVs) requiring manual instrument-tracking; (2) high frame-rates require sparse sampling, which limits FOV; and (3) small iOCT FOV also limits the ability to co-register data with surgical microscopy. We previously addressed these limitations in image-guided ophthalmic microsurgery by developing microscope-integrated multimodal intraoperative swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography. Complementary en face images enabled orientation and coregistration with the widefield surgical microscope view while OCT imaging enabled depth-resolved visualization of surgical instrument positions relative to anatomic structures-of-interest. In addition, we demonstrated novel integrated segmentation overlays for augmented-reality surgical guidance. Unfortunately, our previous system lacked the resolution and optical throughput for in vivo retinal imaging and necessitated removal of cornea and lens. These limitations were predominately a result of optical aberrations from imaging through a shared surgical microscope objective lens, which was modeled as a paraxial surface. Here, we present an optimized intraoperative spectrally encoded coherence tomography and reflectometry (iSECTR) system. We use a novel lens characterization method to develop an accurate model of surgical microscope objective performance and balance out inherent aberrations using iSECTR relay optics. Using this system, we demonstrate in vivo multimodal ophthalmic imaging through a surgical microscope

Design considerations of a real-time clinical confocal microscope

NASA Astrophysics Data System (ADS)

Masters, Barry R.

1991-06-01

A real-time clinical confocal light microscope provides the ophthalmologist with a new tool for the observation of the cornea and the ocular lens. In addition, the ciliary body, the iris, and the sclera can be observed. The real-time light microscopic images have high contrast and resolution. The transverse resolution is about one half micron and the range resolution is one micron. The following observations were made with visible light: corneal epithelial cells, wing cells, basal cells, Bowman's membrane, nerve fibers, basal lamina, fibroblast nuclei, Descemet's membrane, endothelial cells. Observation of the in situ ocular lens showed lens capsule, lens epithelium, lens fibrils, the interior of lens fibrils. The applications of the confocal microscope include: eye banking, laser refractive surgery, observation of wound healing, observation of the iris, the sciera, the ciliary body, the ocular lens, and the intraocular lens. Digital image processing can produce three-dimensional reconstructions of the cornea and the ocular lens.

Live Imaging of Shoot Meristems on an Inverted Confocal Microscope Using an Objective Lens Inverter Attachment

PubMed Central

Nimchuk, Zachary L.; Perdue, Tony D.

2017-01-01

Live imaging of above ground meristems can lead to new insights in plant development not possible from static imaging of fixed tissue. The use of an upright confocal microscope offers several technical and biological advantages for live imaging floral or shoot meristems. However, many departments and core facilities possess only inverted confocal microscopes and lack the funding for an additional upright confocal microscope. Here we show that imaging of living apical meristems can be performed on existing inverted confocal microscopes with the use of an affordable and detachable InverterScope accessory. PMID:28579995

Live Imaging of Shoot Meristems on an Inverted Confocal Microscope Using an Objective Lens Inverter Attachment.

PubMed

Nimchuk, Zachary L; Perdue, Tony D

2017-01-01

Live imaging of above ground meristems can lead to new insights in plant development not possible from static imaging of fixed tissue. The use of an upright confocal microscope offers several technical and biological advantages for live imaging floral or shoot meristems. However, many departments and core facilities possess only inverted confocal microscopes and lack the funding for an additional upright confocal microscope. Here we show that imaging of living apical meristems can be performed on existing inverted confocal microscopes with the use of an affordable and detachable InverterScope accessory.

Optical properties of the magnetic monopole field applied to electron microscopy and spectroscopy

NASA Astrophysics Data System (ADS)

Kruit, P.; Lenc, M.

1992-11-01

An analytical treatment of the electron's motion in a magnetic monopole field results in useful expressions for both the lens action and the mirror action of the field. Using an appropriate definition of the magnetic moment of the electron, it is shown that there is an exact conservation of this parameter in the monopole field, implying that the motion is perfectly adiabatic. This property is important when the field is used for directing Auger electrons from a target to a detector; that is, when it is used as a parallelizer in a through-the-lens detection scheme. Regarding the monopole field as an electron lens, the image position and magnification are derived for an arbitrary object position. Expressions for both the axial aberrations (chromatic and spherical) and the image aberrations (coma, field curvature, astigmatism, distortion, and transverse chromatic) are derived for an arbitrary number of intermediate images between object and final image. The chromatic aberration turns out to be independent of the number of intermediate images and the spherical aberration decreases slightly with this number. This property is important when an electron beam must be focused to a small probe in a strong magnetic field. It is shown that if a certain combination of deflectors is used in conjunction with the monopole field, an ideal swinging objective lens is obtained: All image aberrations except field curvature disappear. Designs are presented in which the monopole field is used in the objective lenses of a transmission electron microscope and a scanning electron microscope.

Instruments for Imaging from Far to Near

NASA Technical Reports Server (NTRS)

Mungas, Greg; Boynton, John; Sepulveda, Cesar

2009-01-01

The acronym CHAMP (signifying camera, hand lens, and microscope ) denotes any of several proposed optoelectronic instruments that would be capable of color imaging at working distances that could be varied continuously through a range from infinity down to several millimeters. As in any optical instrument, the magnification, depth of field, and spatial resolution would vary with the working distance. For example, in one CHAMP version, at a working distance of 2.5 m, the instrument would function as an electronic camera with a magnification of 1/100, whereas at a working distance of 7 mm, the instrument would function as a microscope/electronic camera with a magnification of 4.4. Moreover, as described below, when operating at or near the shortest-working-distance/highest-magnification combination, a CHAMP could be made to perform one or more spectral imaging functions. CHAMPs were originally intended to be used in robotic geological exploration of the Moon and Mars. The CHAMP concept also has potential for diverse terrestrial applications that could include remotely controlled or robotic geological exploration, prospecting, field microbiology, environmental surveying, and assembly- line inspection. A CHAMP (see figure) would include two lens cells: (1) a distal cell corresponding to the objective lens assembly of a conventional telescope or microscope and (2) a proximal cell that would contain the focusing camera lens assembly and the camera electronic image-detector chip, which would be of the active-pixel-sensor (APS) type. The distal lens cell would face outward from a housing, while the proximal lens cell would lie in a clean environment inside the housing. The proximal lens cell would contain a beam splitter that would enable simultaneous use of the imaging optics (that is, proximal and distal lens assemblies) for imaging and illumination of the field of view. The APS chip would be mounted on a focal plane on a side face of the beam splitter, while light for illuminating the field of view would enter the imaging optics via the end face of the beam splitter. The proximal lens cell would be mounted on a sled that could be translated along the optical axis for focus adjustment. The position of the CHAMP would initially be chosen at the desired working distance of the distal lens from (corresponding to an approximate desired magnification of) an object to be examined. During subsequent operation, the working distance would ordinarily remain fixed at the chosen value and the position of the proximal lens cell within the instrument would be adjusted for focus as needed.

High resolution projection X-ray microscope equipped with fluorescent X-ray analyzer and its applications

NASA Astrophysics Data System (ADS)

Minami, K.; Saito, Y.; Kai, H.; Shirota, K.; Yada, K.

2009-09-01

We have newly developed an open type fine-focus X-ray tube "TX-510" to realize a spatial resolution of 50nm and to radiate low energy characteristic X-rays for giving high absorption contrast to images of microscopic organisms. The "TX-510" employs a ZrO/W(100) Schottky emitter and an "In-Lens Field Emission Gun". The key points of the improvements are (1) reduced spherical aberration coefficient of magnetic objective lens, (2) easy and accurate focusing, (3) newly designed astigmatism compensator, (4) segmented thin film target for interchanging the target materials by electron beam shift and (5) fluorescent X-ray analysis system.

Advantages of using newly developed quartz contact lens with slit illumination from operating microscope.

PubMed

Kiyokawa, Masatoshi; Sakuma, Toshiro; Hatano, Noriko; Mizota, Atsushi; Tanaka, Minoru

2009-06-01

The purpose of this article is to report the characteristics and advantages of using a newly designed quartz contact lens with slit illumination from an operating microscope for intraocular surgery. The new contact lens is made of quartz. The lens is convex-concave and is used in combination with slit illumination from an operating microscope. The optical properties of quartz make this lens less reflective with greater transmittance. The combination of a quartz contact lens with slit illumination provided a brighter and wider field of view than conventional lenses. This system enabled us to perform bimanual vitrectomy and scleral buckling surgery without indirect ophthalmoscope. Small intraocular structures in the posterior pole or in the periphery were detected more easily. In conclusion, the newly designed quartz lens with slit beam illumination from an operating microscope provided a bright, clear and wide surgical field, and allowed intraocular surgery to be performed more easily.

Sub-cell turning to accomplish micron-level alignment of precision assemblies

NASA Astrophysics Data System (ADS)

Kumler, James J.; Buss, Christian

2017-08-01

Higher performance expectations for complex optical systems demand tighter alignment requirements for lens assembly alignment. In order to meet diffraction limited imaging performance over wide spectral bands across the UV and visible wavebands, new manufacturing approaches and tools must be developed if the optical systems will be produced consistently in volume production. This is especially applicable in the field of precision microscope objectives for life science, semiconductor inspection and laser material processing systems. We observe a rising need for the improvement in the optical imaging performance of objective lenses. The key challenge lies in the micron-level decentration and tilt of each lens element. One solution for the production of high quality lens systems is sub-cell assembly with alignment turning. This process relies on an automatic alignment chuck to align the optical axis of a mounted lens to the spindle axis of the machine. Subsequently, the mount is cut with diamond tools on a lathe with respect to the optical axis of the mount. Software controlled integrated measurement technology ensures highest precision. In addition to traditional production processes, further dimensions can be controlled in a very precise manner, e.g. the air gaps between the lenses. Using alignment turning simplifies further alignment steps and reduces the risk of errors. This paper describes new challenges in microscope objective design and manufacturing, and addresses difficulties with standard production processes. A new measurement and alignment technique is described, and strengths and limitations are outlined.

LC-lens array with light field algorithm for 3D biomedical applications

NASA Astrophysics Data System (ADS)

Huang, Yi-Pai; Hsieh, Po-Yuan; Hassanfiroozi, Amir; Martinez, Manuel; Javidi, Bahram; Chu, Chao-Yu; Hsuan, Yun; Chu, Wen-Chun

2016-03-01

In this paper, liquid crystal lens (LC-lens) array was utilized in 3D bio-medical applications including 3D endoscope and light field microscope. Comparing with conventional plastic lens array, which was usually placed in 3D endoscope or light field microscope system to record image disparity, our LC-lens array has higher flexibility of electrically changing its focal length. By using LC-lens array, the working distance and image quality of 3D endoscope and microscope could be enhanced. Furthermore, the 2D/3D switching ability could be achieved if we turn off/on the electrical power on LClens array. In 3D endoscope case, a hexagonal micro LC-lens array with 350um diameter was placed at the front end of a 1mm diameter endoscope. With applying electric field on LC-lens array, the 3D specimen would be recorded as from seven micro-cameras with different disparity. We could calculate 3D construction of specimen with those micro images. In the other hand, if we turn off the electric field on LC-lens array, the conventional high resolution 2D endoscope image would be recorded. In light field microscope case, the LC-lens array was placed in front of the CMOS sensor. The main purpose of LC-lens array is to extend the refocusing distance of light field microscope, which is usually very narrow in focused light field microscope system, by montaging many light field images sequentially focusing on different depth. With adjusting focal length of LC-lens array from 2.4mm to 2.9mm, the refocusing distance was extended from 1mm to 11.3mm. Moreover, we could use a LC wedge to electrically shift the optics axis and increase the resolution of light field.

The microscopes of Antoni van Leeuwenhoek.

PubMed

van Zuylen, J

1981-03-01

The seventeenth-century Dutch microscopist, Antoni van Leeuwenhoek, was the first man to make a protracted study of microscopical objects, and, unlike his contemporary Robert Hooke, he viewed by transmitted light. Leeuwenhoek made over 500 of his own, curious, simple microscopes, but now only nine are known to exist. The exact nature of the lenses Leeuwenhoek made, has for long been a puzzle. The existing microscopes have now been examined in detail, and their optical characteristics measured and tabulated. It is proposed that the lens of highest magnification, x 266, was made using a special blown bubble technique.

Enabling the detection of UV signal in multimodal nonlinear microscopy with catalogue lens components.

PubMed

Vogel, Martin; Wingert, Axel; Fink, Rainer H A; Hagl, Christian; Ganikhanov, Feruz; Pfeffer, Christian P

2015-10-01

Using an optical system made from fused silica catalogue optical components, third-order nonlinear microscopy has been enabled on conventional Ti:sapphire laser-based multiphoton microscopy setups. The optical system is designed using two lens groups with straightforward adaptation to other microscope stands when one of the lens groups is exchanged. Within the theoretical design, the optical system collects and transmits light with wavelengths between the near ultraviolet and the near infrared from an object field of at least 1 mm in diameter within a resulting numerical aperture of up to 0.56. The numerical aperture can be controlled with a variable aperture stop between the two lens groups of the condenser. We demonstrate this new detection capability in third harmonic generation imaging experiments at the harmonic wavelength of ∼300 nm and in multimodal nonlinear optical imaging experiments using third-order sum frequency generation and coherent anti-Stokes Raman scattering microscopy so that the wavelengths of the detected signals range from ∼300 nm to ∼660 nm. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

A new Brewster angle microscope

NASA Astrophysics Data System (ADS)

Lheveder, C.; Hénon, S.; Mercier, R.; Tissot, G.; Fournet, P.; Meunier, J.

1998-03-01

We present a new Brewster angle microscope for the study of very thin layers as thin as monolayers, using a custom-made objective. This objective avoids the drawbacks of the models existing at the present time. Its optical axis is perpendicular to the studied layer and consequently gives an image in focus in all the plane contrary to the existing models which give images in focus along a narrow strip. The objective allows one to obtain images with a good resolution (less than 1 μm) without scanning the surface, at the video frequency, allowing for dynamic studies. A large frontal distance associated with a very large aperture is obtained by using a large lens at the entrance of the objective.

Wavefront correction and high-resolution in vivo OCT imaging with an objective integrated multi-actuator adaptive lens.

PubMed

Bonora, Stefano; Jian, Yifan; Zhang, Pengfei; Zam, Azhar; Pugh, Edward N; Zawadzki, Robert J; Sarunic, Marinko V

2015-08-24

Adaptive optics is rapidly transforming microscopy and high-resolution ophthalmic imaging. The adaptive elements commonly used to control optical wavefronts are liquid crystal spatial light modulators and deformable mirrors. We introduce a novel Multi-actuator Adaptive Lens that can correct aberrations to high order, and which has the potential to increase the spread of adaptive optics to many new applications by simplifying its integration with existing systems. Our method combines an adaptive lens with an imaged-based optimization control that allows the correction of images to the diffraction limit, and provides a reduction of hardware complexity with respect to existing state-of-the-art adaptive optics systems. The Multi-actuator Adaptive Lens design that we present can correct wavefront aberrations up to the 4th order of the Zernike polynomial characterization. The performance of the Multi-actuator Adaptive Lens is demonstrated in a wide field microscope, using a Shack-Hartmann wavefront sensor for closed loop control. The Multi-actuator Adaptive Lens and image-based wavefront-sensorless control were also integrated into the objective of a Fourier Domain Optical Coherence Tomography system for in vivo imaging of mouse retinal structures. The experimental results demonstrate that the insertion of the Multi-actuator Objective Lens can generate arbitrary wavefronts to correct aberrations down to the diffraction limit, and can be easily integrated into optical systems to improve the quality of aberrated images.

(LMRG): Microscope Resolution, Objective Quality, Spectral Accuracy and Spectral Un-mixing

PubMed Central

Bayles, Carol J.; Cole, Richard W.; Eason, Brady; Girard, Anne-Marie; Jinadasa, Tushare; Martin, Karen; McNamara, George; Opansky, Cynthia; Schulz, Katherine; Thibault, Marc; Brown, Claire M.

2012-01-01

The second study by the LMRG focuses on measuring confocal laser scanning microscope (CLSM) resolution, objective lens quality, spectral imaging accuracy and spectral un-mixing. Affordable test samples for each aspect of the study were designed, prepared and sent to 116 labs from 23 countries across the globe. Detailed protocols were designed for the three tests and customized for most of the major confocal instruments being used by the study participants. One protocol developed for measuring resolution and objective quality was recently published in Nature Protocols (Cole, R. W., T. Jinadasa, et al. (2011). Nature Protocols 6(12): 1929–1941). The first study involved 3D imaging of sub-resolution fluorescent microspheres to determine the microscope point spread function. Results of the resolution studies as well as point spread function quality (i.e. objective lens quality) from 140 different objective lenses will be presented. The second study of spectral accuracy looked at the reflection of the laser excitation lines into the spectral detection in order to determine the accuracy of these systems to report back the accurate laser emission wavelengths. Results will be presented from 42 different spectral confocal systems. Finally, samples with double orange beads (orange core and orange coating) were imaged spectrally and the imaging software was used to un-mix fluorescence signals from the two orange dyes. Results from 26 different confocal systems will be summarized. Time will be left to discuss possibilities for the next LMRG study.

Images created in a model eye during simulated cataract surgery can be the basis for images perceived by patients during cataract surgery

PubMed Central

Inoue, M; Uchida, A; Shinoda, K; Taira, Y; Noda, T; Ohnuma, K; Bissen-Miyajima, H; Hirakata, A

2014-01-01

Purpose To evaluate the images created in a model eye during simulated cataract surgery. Patients and methods This study was conducted as a laboratory investigation and interventional case series. An artificial opaque lens, a clear intraocular lens (IOL), or an irrigation/aspiration (I/A) tip was inserted into the ‘anterior chamber' of a model eye with the frosted posterior surface corresponding to the retina. Video images were recorded of the posterior surface of the model eye from the rear during simulated cataract surgery. The video clips were shown to 20 patients before cataract surgery, and the similarity of their visual perceptions to these images was evaluated postoperatively. Results The images of the moving lens fragments and I/A tip and the insertion of the IOL were seen from the rear. The image through the opaque lens and the IOL without moving objects was the light of the surgical microscope from the rear. However, when the microscope light was turned off after IOL insertion, the images of the microscope and operating room were observed by the room illumination from the rear. Seventy percent of the patients answered that the visual perceptions of moving lens fragments were similar to the video clips and 55% reported similarity with the IOL insertion. Eighty percent of the patients recommended that patients watch the video clip before their scheduled cataract surgery. Conclusions The patients' visual perceptions during cataract surgery can be reproduced in the model eye. Watching the video images preoperatively may help relax the patients during surgery. PMID:24788007

Foucault imaging by using non-dedicated transmission electron microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taniguchi, Yoshifumi; Matsumoto, Hiroaki; Harada, Ken

2012-08-27

An electron optical system for observing Foucault images was constructed using a conventional transmission electron microscope without any special equipment for Lorentz microscopy. The objective lens was switched off and an electron beam was converged by a condenser optical system to the crossover on the selected area aperture plane. The selected area aperture was used as an objective aperture to select the deflected beam for Foucault mode, and the successive image-forming lenses were controlled for observation of the specimen images. The irradiation area on the specimen was controlled by selecting the appropriate diameter of the condenser aperture.

The relationship between morphological changes of lens epithelial cells and intraocular lens optic material.

PubMed

Majima, K

1998-01-01

To examine the morphological changes of lens epithelial cells (LECs) occurring directly beneath and at regions contacting various intraocular lens (IOL) optic materials, human LECs were cultured on human anterior lens capsules and were further incubated upon placing above the cells lens optics made of polymethylmethacrylate, silicone, and soft acrylic material. Observations as to the morphological changes of LECs under phase-contrast microscope and scanning electron microscope were performed on the 14th day of incubation. Gatherings of LECs were observed at regions contacting the soft acrylic material under phase-contrast microscope, and gatherings of LECs were observed accurately at the same regions mentioned above under scanning electron microscope. On the other hand, LECs in contact with two other optic materials did not show morphological changes. The results suggest that LECs attached to and proliferated on not only the anterior lens capsules but also the soft acrylic IOL optics. The model used in this study may be useful in studying the relationship between cellular movement of LECs and IOL optic material.

Augmented Reality Technology Using Microsoft HoloLens in Anatomic Pathology.

PubMed

Hanna, Matthew G; Ahmed, Ishtiaque; Nine, Jeffrey; Prajapati, Shyam; Pantanowitz, Liron

2018-05-01

Context Augmented reality (AR) devices such as the Microsoft HoloLens have not been well used in the medical field. Objective To test the HoloLens for clinical and nonclinical applications in pathology. Design A Microsoft HoloLens was tested for virtual annotation during autopsy, viewing 3D gross and microscopic pathology specimens, navigating whole slide images, telepathology, as well as real-time pathology-radiology correlation. Results Pathology residents performing an autopsy wearing the HoloLens were remotely instructed with real-time diagrams, annotations, and voice instruction. 3D-scanned gross pathology specimens could be viewed as holograms and easily manipulated. Telepathology was supported during gross examination and at the time of intraoperative consultation, allowing users to remotely access a pathologist for guidance and to virtually annotate areas of interest on specimens in real-time. The HoloLens permitted radiographs to be coregistered on gross specimens and thereby enhanced locating important pathologic findings. The HoloLens also allowed easy viewing and navigation of whole slide images, using an AR workstation, including multiple coregistered tissue sections facilitating volumetric pathology evaluation. Conclusions The HoloLens is a novel AR tool with multiple clinical and nonclinical applications in pathology. The device was comfortable to wear, easy to use, provided sufficient computing power, and supported high-resolution imaging. It was useful for autopsy, gross and microscopic examination, and ideally suited for digital pathology. Unique applications include remote supervision and annotation, 3D image viewing and manipulation, telepathology in a mixed-reality environment, and real-time pathology-radiology correlation.

Magnetic lens apparatus for a low-voltage high-resolution electron microscope

DOEpatents

Crewe, Albert V.

1996-01-01

A lens apparatus in which a beam of charged particles of low accelerating voltage is brought to a focus by a magnetic field, the lens being situated behind the target position. The lens comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. The lens apparatus comprises the sole focusing lens for high-resolution imaging in a low-voltage scanning electron microscope.

Optical Detection and Sizing of Single Nano-Particles Using Continuous Wetting Films

PubMed Central

Hennequin, Yves; McLeod, Euan; Mudanyali, Onur; Migliozzi, Daniel; Ozcan, Aydogan; Dinten, Jean-Marc

2013-01-01

The physical interaction between nano-scale objects and liquid interfaces can create unique optical properties, enhancing the signatures of the objects with sub-wavelength features. Here we show that the evaporation on a wetting substrate of a polymer solution containing sub-micrometer or nano-scale particles creates liquid micro-lenses that arise from the local deformations of the continuous wetting film. These micro-lenses have properties similar to axicon lenses that are known to create beams with a long depth of focus. This enhanced depth of focus allows detection of single nanoparticles using a low magnification microscope objective lens, achieving a relatively wide field-of-view, while also lifting the constraints on precise focusing onto the object plane. Hence, by creating these liquid axicon lenses through spatial deformations of a continuous thin wetting film, we transfer the challenge of imaging individual nano-particles to detecting the light focused by these lenses. As a proof of concept, we demonstrate the detection and sizing of single nano-particles (100 and 200 nm), CpGV granuloviruses as well as Staphylococcus epidermidis bacteria over a wide field of view of e.g., 5.10×3.75 mm2 using a ×5 objective lens with a numerical aperture of 0.15. In addition to conventional lens-based microscopy, this continuous wetting film based approach is also applicable to lensfree computational on-chip imaging, which can be used to detect single nano-particles over a large field-of-view of e.g., >20-30 mm2. These results could be especially useful for high-throughput field-analysis of nano-scale objects using compact and cost-effective microscope designs. PMID:23889001

Wavefront correction and high-resolution in vivo OCT imaging with an objective integrated multi-actuator adaptive lens

PubMed Central

Bonora, Stefano; Jian, Yifan; Zhang, Pengfei; Zam, Azhar; Pugh, Edward N.; Zawadzki, Robert J.; Sarunic, Marinko V.

2015-01-01

Adaptive optics is rapidly transforming microscopy and high-resolution ophthalmic imaging. The adaptive elements commonly used to control optical wavefronts are liquid crystal spatial light modulators and deformable mirrors. We introduce a novel Multi-actuator Adaptive Lens that can correct aberrations to high order, and which has the potential to increase the spread of adaptive optics to many new applications by simplifying its integration with existing systems. Our method combines an adaptive lens with an imaged-based optimization control that allows the correction of images to the diffraction limit, and provides a reduction of hardware complexity with respect to existing state-of-the-art adaptive optics systems. The Multi-actuator Adaptive Lens design that we present can correct wavefront aberrations up to the 4th order of the Zernike polynomial characterization. The performance of the Multi-actuator Adaptive Lens is demonstrated in a wide field microscope, using a Shack-Hartmann wavefront sensor for closed loop control. The Multi-actuator Adaptive Lens and image-based wavefront-sensorless control were also integrated into the objective of a Fourier Domain Optical Coherence Tomography system for in vivo imaging of mouse retinal structures. The experimental results demonstrate that the insertion of the Multi-actuator Objective Lens can generate arbitrary wavefronts to correct aberrations down to the diffraction limit, and can be easily integrated into optical systems to improve the quality of aberrated images. PMID:26368169

A pragmatic guide to multiphoton microscope design

PubMed Central

Young, Michael D.; Field, Jeffrey J.; Sheetz, Kraig E.; Bartels, Randy A.; Squier, Jeff

2016-01-01

Multiphoton microscopy has emerged as a ubiquitous tool for studying microscopic structure and function across a broad range of disciplines. As such, the intent of this paper is to present a comprehensive resource for the construction and performance evaluation of a multiphoton microscope that will be understandable to the broad range of scientific fields that presently exploit, or wish to begin exploiting, this powerful technology. With this in mind, we have developed a guide to aid in the design of a multiphoton microscope. We discuss source selection, optical management of dispersion, image-relay systems with scan optics, objective-lens selection, single-element light-collection theory, photon-counting detection, image rendering, and finally, an illustrated guide for building an example microscope. PMID:27182429

Common path in-line holography using enhanced joint object reference digital interferometers

PubMed Central

Kelner, Roy; Katz, Barak; Rosen, Joseph

2014-01-01

Joint object reference digital interferometer (JORDI) is a recently developed system capable of recording holograms of various types [Opt. Lett. 38(22), 4719 (2013)24322115]. Presented here is a new enhanced system design that is based on the previous JORDI. While the previous JORDI has been based purely on diffractive optical elements, displayed on spatial light modulators, the present design incorporates an additional refractive objective lens, thus enabling hologram recording with improved resolution and increased system applicability. Experimental results demonstrate successful hologram recording for various types of objects, including transmissive, reflective, three-dimensional, phase and highly scattering objects. The resolution limit of the system is analyzed and experimentally validated. Finally, the suitability of JORDI for microscopic applications is verified as a microscope objective based configuration of the system is demonstrated. PMID:24663838

Miniature objective lens for array digital pathology: design improvement based on clinical evaluation

NASA Astrophysics Data System (ADS)

McCall, Brian; Pierce, Mark; Graviss, Edward A.; Richards-Kortum, Rebecca R.; Tkaczyk, Tomasz S.

2016-03-01

A miniature objective designed for digital detection of Mycobacterium tuberculosis (MTB) was evaluated for diagnostic accuracy. The objective was designed for array microscopy, but fabricated and evaluated at this stage of development as a single objective. The counts and diagnoses of patient samples were directly compared for digital detection and standard microscopy. The results were found to be correlated and highly concordant. The evaluation of this lens by direct comparison to standard fluorescence sputum smear microscopy presented unique challenges and led to some new insights in the role played by the system parameters of the microscope. The design parameters and how they were developed are reviewed in light of these results. New system parameters are proposed with the goal of easing the challenges of evaluating the miniature objective and maintaining the optical performance that produced the agreeable results presented without over-optimizing. A new design is presented that meets and exceeds these criteria.

Studies on Muon Induction Acceleration and an Objective Lens Design for Transmission Muon Microscope

NASA Astrophysics Data System (ADS)

Artikova, Sayyora; Yoshida, Mitsuhiro; Naito, Fujio

Muon acceleration will be accomplished by a set of induction cells, where each increases the energy of the muon beam by an increment of up to 30 kV. The cells are arranged in a linear way resulting in total accelerating voltage of 300 kV. Acceleration time in the linac is about hundred nanoseconds. Induction field calculation is based on an electrostatic approximation. Beam dynamics in the induction accelerator is investigated and final beam focusing on specimen is realized by designing a pole piece lens.

All-optical optoacoustic microscopy system based on probe beam deflection technique

NASA Astrophysics Data System (ADS)

Maswadi, Saher M.; Tsyboulskic, Dmitri; Roth, Caleb C.; Glickman, Randolph D.; Beier, Hope T.; Oraevsky, Alexander A.; Ibey, Bennett L.

2016-03-01

It is difficult to achieve sub-micron resolution in backward mode OA microscopy using conventional piezoelectric detectors, because of wavefront distortions caused by components placed in the optical path, between the sample and the objective lens, that are required to separate the acoustic wave from the optical beam. As an alternate approach, an optoacoustic microscope (OAM) was constructed using the probe beam deflection technique (PBDT) to detect laserinduced acoustic signals. The all-optical OAM detects laser-generated pressure waves using a probe beam passing through a coupling medium, such as water, filling the space between the microscope objective lens and sample. The acoustic waves generated in the sample propagate through the coupling medium, causing transient changes in the refractive index that deflect the probe beam. These deflections are measured with a high-speed, balanced photodiode position detector. The deflection amplitude is directly proportional to the magnitude of the acoustic pressure wave, and provides the data required for image reconstruction. The sensitivity of the PBDT detector expressed as noise equivalent pressure was 12 Pa, comparable to that of existing high-performance ultrasound detectors. Because of the unimpeded working distance, a high numerical aperture objective lens, i.e. NA = 1, was employed in the OAM to achieve near diffraction-limited lateral resolution of 0.5 μm at 532nm. The all-optical OAM provides several benefits over current piezoelectric detector-based systems, such as increased lateral and axial resolution, higher sensitivity, robustness, and potentially more compatibility with multimodal instruments.

Computer synthesis of high resolution electron micrographs

NASA Technical Reports Server (NTRS)

Nathan, R.

1976-01-01

Specimen damage, spherical aberration, low contrast and noisy sensors combine to prevent direct atomic viewing in a conventional electron microscope. The paper describes two methods for obtaining ultra-high resolution in biological specimens under the electron microscope. The first method assumes the physical limits of the electron objective lens and uses a series of dark field images of biological crystals to obtain direct information on the phases of the Fourier diffraction maxima; this information is used in an appropriate computer to synthesize a large aperture lens for a 1-A resolution. The second method assumes there is sufficient amplitude scatter from images recorded in focus which can be utilized with a sensitive densitometer and computer contrast stretching to yield fine structure image details. Cancer virus characterization is discussed as an illustrative example. Numerous photographs supplement the text.

Speckle-free and halo-free low coherent Mach-Zehnder quantitative-phase-imaging module as a replacement of objective lens in conventional inverted microscopes

NASA Astrophysics Data System (ADS)

Yamauchi, Toyohiko; Yamada, Hidenao; Matsui, Hisayuki; Yasuhiko, Osamu; Ueda, Yukio

2018-02-01

We developed a compact Mach-Zehnder interferometer module to be used as a replacement of the objective lens in a conventional inverted microscope (Nikon, TS100-F) in order to make them quantitative phase microscopes. The module has a 90-degree-flipped U-shape; the dimensions of the module are 160 mm by 120 mm by 40 mm and the weight is 380 grams. The Mach-Zehnder interferometer equipped with the separate reference and sample arms was implemented in this U-shaped housing and the path-length difference between the two arms was manually adjustable. The sample under test was put on the stage of the microscope and a sample light went through it. Both arms had identical achromatic lenses for image formation and the lateral positions of them were also manually adjustable. Therefore, temporally and spatially low coherent illumination was applicable because the users were able to balance precisely the path length of the two arms and to overlap the two wavefronts. In the experiment, spectrally filtered LED light for illumination (wavelength = 633 nm and bandwidth = 3 nm) was input to the interferometer module via a 50 micrometer core optical fiber. We have successfully captured full-field interference images by a camera put on the trinocular tube of the microscope and constructed quantitative phase images of the cultured cells by means of the quarter-wavelength phase shifting algorithm. The resultant quantitative phase images were speckle-free and halo-free due to spectrally and spatially low coherent illumination.

Dermoscopy-guided reflectance confocal microscopy of skin using high-NA objective lens with integrated wide-field color camera

NASA Astrophysics Data System (ADS)

Dickensheets, David L.; Kreitinger, Seth; Peterson, Gary; Heger, Michael; Rajadhyaksha, Milind

2016-02-01

Reflectance Confocal Microscopy, or RCM, is being increasingly used to guide diagnosis of skin lesions. The combination of widefield dermoscopy (WFD) with RCM is highly sensitive (~90%) and specific (~ 90%) for noninvasively detecting melanocytic and non-melanocytic skin lesions. The combined WFD and RCM approach is being implemented on patients to triage lesions into benign (with no biopsy) versus suspicious (followed by biopsy and pathology). Currently, however, WFD and RCM imaging are performed with separate instruments, while using an adhesive ring attached to the skin to sequentially image the same region and co-register the images. The latest small handheld RCM instruments offer no provision yet for a co-registered wide-field image. This paper describes an innovative solution that integrates an ultra-miniature dermoscopy camera into the RCM objective lens, providing simultaneous wide-field color images of the skin surface and RCM images of the subsurface cellular structure. The objective lens (0.9 NA) includes a hyperhemisphere lens and an ultra-miniature CMOS color camera, commanding a 4 mm wide dermoscopy view of the skin surface. The camera obscures the central portion of the aperture of the objective lens, but the resulting annular aperture provides excellent RCM optical sectioning and resolution. Preliminary testing on healthy volunteers showed the feasibility of combined WFD and RCM imaging to concurrently show the skin surface in wide-field and the underlying microscopic cellular-level detail. The paper describes this unique integrated dermoscopic WFD/RCM lens, and shows representative images. The potential for dermoscopy-guided RCM for skin cancer diagnosis is discussed.

Dermoscopy-guided reflectance confocal microscopy of skin using high-NA objective lens with integrated wide-field color camera.

PubMed

Dickensheets, David L; Kreitinger, Seth; Peterson, Gary; Heger, Michael; Rajadhyaksha, Milind

2016-02-01

Reflectance Confocal Microscopy, or RCM, is being increasingly used to guide diagnosis of skin lesions. The combination of widefield dermoscopy (WFD) with RCM is highly sensitive (~90%) and specific (~ 90%) for noninvasively detecting melanocytic and non-melanocytic skin lesions. The combined WFD and RCM approach is being implemented on patients to triage lesions into benign (with no biopsy) versus suspicious (followed by biopsy and pathology). Currently, however, WFD and RCM imaging are performed with separate instruments, while using an adhesive ring attached to the skin to sequentially image the same region and co-register the images. The latest small handheld RCM instruments offer no provision yet for a co-registered wide-field image. This paper describes an innovative solution that integrates an ultra-miniature dermoscopy camera into the RCM objective lens, providing simultaneous wide-field color images of the skin surface and RCM images of the subsurface cellular structure. The objective lens (0.9 NA) includes a hyperhemisphere lens and an ultra-miniature CMOS color camera, commanding a 4 mm wide dermoscopy view of the skin surface. The camera obscures the central portion of the aperture of the objective lens, but the resulting annular aperture provides excellent RCM optical sectioning and resolution. Preliminary testing on healthy volunteers showed the feasibility of combined WFD and RCM imaging to concurrently show the skin surface in wide-field and the underlying microscopic cellular-level detail. The paper describes this unique integrated dermoscopic WFD/RCM lens, and shows representative images. The potential for dermoscopy-guided RCM for skin cancer diagnosis is discussed.

Sub-micrometer resolution proximity X-ray microscope with digital image registration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chkhalo, N. I.; Salashchenko, N. N.; Sherbakov, A. V., E-mail: SherbakovAV@ipm.sci-nnov.ru

A compact laboratory proximity soft X-ray microscope providing submicrometer spatial resolution and digital image registration is described. The microscope consists of a laser-plasma soft X-ray radiation source, a Schwarzschild objective to illuminate the test sample, and a two-coordinate detector for image registration. Radiation, which passes through the sample under study, generates an absorption image on the front surface of the detector. Optical ceramic YAG:Ce was used to convert the X-rays into visible light. An image was transferred from the scintillator to a charge-coupled device camera with a Mitutoyo Plan Apo series lens. The detector’s design allows the use of lensesmore » with numerical apertures of NA = 0.14, 0.28, and 0.55 without changing the dimensions and arrangement of the elements of the device. This design allows one to change the magnification, spatial resolution, and field of view of the X-ray microscope. A spatial resolution better than 0.7 μm and an energy conversion efficiency of the X-ray radiation with a wavelength of 13.5 nm into visible light collected by the detector of 7.2% were achieved with the largest aperture lens.« less

Automated Micro-Object Detection for Mobile Diagnostics Using Lens-Free Imaging Technology

PubMed Central

Roy, Mohendra; Seo, Dongmin; Oh, Sangwoo; Chae, Yeonghun; Nam, Myung-Hyun; Seo, Sungkyu

2016-01-01

Lens-free imaging technology has been extensively used recently for microparticle and biological cell analysis because of its high throughput, low cost, and simple and compact arrangement. However, this technology still lacks a dedicated and automated detection system. In this paper, we describe a custom-developed automated micro-object detection method for a lens-free imaging system. In our previous work (Roy et al.), we developed a lens-free imaging system using low-cost components. This system was used to generate and capture the diffraction patterns of micro-objects and a global threshold was used to locate the diffraction patterns. In this work we used the same setup to develop an improved automated detection and analysis algorithm based on adaptive threshold and clustering of signals. For this purpose images from the lens-free system were then used to understand the features and characteristics of the diffraction patterns of several types of samples. On the basis of this information, we custom-developed an automated algorithm for the lens-free imaging system. Next, all the lens-free images were processed using this custom-developed automated algorithm. The performance of this approach was evaluated by comparing the counting results with standard optical microscope results. We evaluated the counting results for polystyrene microbeads, red blood cells, HepG2, HeLa, and MCF7 cells lines. The comparison shows good agreement between the systems, with a correlation coefficient of 0.91 and linearity slope of 0.877. We also evaluated the automated size profiles of the microparticle samples. This Wi-Fi-enabled lens-free imaging system, along with the dedicated software, possesses great potential for telemedicine applications in resource-limited settings. PMID:27164146

Applications of rigid and flexible GRIN-endoscopes

NASA Astrophysics Data System (ADS)

Schenkl, Selma; Ehlers, Alexander; Riemann, Iris; Messerschmidt, Bernhard; Bückle, Rainer; König, Karsten

2007-02-01

Multiphoton autofluorescence imaging became an important technique for minimal invasive examination of cells in biological tissue. Rigid and flexible endoscopes based on gradient index lenses (GRIN-lenses) extend this minimalinvasive technique to deep lying cell layers, inner body and specimens, difficult to access. In the rigid endoscope, a GRIN-lens overcomes the limited depth range, given by the working distance of the microscope objective. The focus of the conventional laser scanning tomography is reproduced tens of millimeters in the specimen under study by the GRIN-lens (diameter 1.8 and 3 μm). We will present images of fluorescent beads, proteins cells and skin tissue, as well as first in vivo measurements on human skin. The autofluorescence signal stems from the endogenous fluorophore elastin and SHG from collagen. The flexible endoscope dispenses completely the need of a microscope next to the specimen of interest. The excitation laser pulses is delivered via a well-characterized photonic crystal fiber and subsequently focused by a newly designed GRIN-lens system. The fluorescence, also transferred by a fiber is detected by a PMT detector. We will show the excellent imaging qualities of a newly developed GRIN-lens system with high-resolution images of proteins, cells and plant tissue and give an out-look on multiphoton endoscopy.

Optimal lens design and use in laser-scanning microscopy

PubMed Central

Negrean, Adrian; Mansvelder, Huibert D.

2014-01-01

In laser-scanning microscopy often an off-the-shelf achromatic doublet is used as a scan lens which can reduce the available diffraction-limited field-of-view (FOV) by a factor of 3 and introduce chromatic aberrations that are scan angle dependent. Here we present several simple lens designs of superior quality that fully make use of high-NA low-magnification objectives, offering diffraction-limited imaging over a large FOV and wavelength range. We constructed a two-photon laser-scanning microscope with optimized custom lenses which had a near diffraction limit point-spread-function (PSF) with less than 3.6% variation over a 400 µm FOV and less than 0.5 µm lateral color between 750 and 1050 nm. PMID:24877017

Comprehensive study of unexpected microscope condensers formed in sample arrangements commonly used in optical microscopy.

PubMed

Desai, Darshan B; Aldawsari, Mabkhoot Mudith S; Alharbi, Bandar Mohammed H; Sen, Sanchari; Grave de Peralta, Luis

2015-09-01

We show that various setups for optical microscopy which are commonly used in biomedical laboratories behave like efficient microscope condensers that are responsible for observed subwavelength resolution. We present a series of experiments and simulations that reveal how inclined illumination from such unexpected condensers occurs when the sample is perpendicularly illuminated by a microscope's built-in white-light source. In addition, we demonstrate an inexpensive add-on optical module that serves as an efficient and lightweight microscope condenser. Using such add-on optical module in combination with a low-numerical-aperture objective lens and Fourier plane imaging microscopy technique, we demonstrate detection of photonic crystals with a period nearly eight times smaller than the Rayleigh resolution limit.

Attenuation of midinfrared free electron laser energy with eyewear

NASA Astrophysics Data System (ADS)

Joos, Karen M.; Gabella, William

2005-04-01

Purpose: To determine the attenuation of free electron laser (FEL) energy at several wavelengths through microscope objective and eyeglass lenses. Materials and Methods: The FEL at wavelengths of 2.3 um, 2.5 um, 3.0 um, 3.5 um, 4.0 um, 4.5 um, 5.0 um, 6.45 um, 7.0 um, 7.5 um, and 8.0 um was telescoped using a 500 mm nominal focal length lens and a 200 mm focal length lens. The beam had a final spot of about 3 mm and was passed through a 3 mm aperture and onto the 8 mm active area of a J9LP Molectron detector. The eyeglass sample was placed 3 cm in front of the detector. Energy readings were averaged over multiple pulses. Results: Attenuation varied greatly with wavelength and sample from a low attenuation of 0.46 dB, 90% transmission, for short wavelengths through common glass to greater than 60 dB attenuation (transmission at the detector noise level) for IR safe glass by Aura, Inc. Conclusion: Only the designated laser safety goggles effectively attenuate free electron laser energy at 2.3 um and 2.5 um. A microscope objective lens, polycarbonate, and silica glass eyewear is capable of effectively attenuating FEL energy at wavelengths greater than 4.5 um, but the polycarbonate lenses demonstrated material damage.

Ophthalmic applications of confocal microscopy: diagnostics, refractive surgery, and eye banking

NASA Astrophysics Data System (ADS)

Masters, Barry R.

1990-11-01

Confocal microscopy of ocular tissue provides two advantages over traditional imaging techniques: increased range and transverse resolution and increased contrast. The semitransparent cornea and ocular lens in the living eye can be optically sectioned and observed by reflected light confocal microscopy. Within the cornea we observed various cell components nerve fibers nerve cell bodies and fibrous networks. The confocal microscopic images from the in-situ ocular lens show the lens capsule the lens epithelium and the individual lens fibrils. All of the reflected light confocal microscopic images have high contrast and high resolution. Some of the applications of confocal imaging in ophthalmology include: diagnostics of the cornea and the ocular lens examination prior to and after refractive surgery examination of intraocular lenses (IOL) and examination of eye bank material. Other ophthalmic uses of confocal imaging include: studies of wound healing therapeutics and the effects of contact lenses on the cornea. The proposed features of a clinical confocal microscope are reviewed. 2.

Macular photostress and visual experience between microscope and intracameral illumination during cataract surgery.

PubMed

Seo, Hyejin; Nam, Dong Heun; Lee, Jong Yeon; Park, Su Jin; Kim, Yu Jeong; Kim, Seong-Woo; Chung, Tae-Young; Inoue, Makoto; Kim, Terry

2018-02-01

To evaluate macular photostress and visual experience between coaxial microscope illumination versus oblique intracameral illumination during cataract surgery. Gachon University Gil Hospital, Incheon, South Korea. Prospective case series. Consecutive patients who had cataract surgery using microscope illumination and intracameral illumination were included. The patients were asked to complete a questionnaire (seeing strong lights, feeling photophobia, feeling startled (fright) when seeing lights, seeing any colors, seeing any instruments or surgical procedures, and estimating intraoperative visual function) designed to describe their cataract surgery experience. The images projected on the retina of the model eye (rear view) with artificial opaque fragments in the anterior chamber during simulating cataract surgery were compared between the 2 illumination types. Sixty patients completed the questionnaire. Scores for strong lights, photophobia, fright, and color perception were significantly higher with microscope illumination than with intracameral illumination (all P < .001). More patients preferred the intracameral illumination (45 [75.0%]) to the microscope illumination (13 [21.7%]). In the rear-view images created in a model eye, only the bright microscope light in the center was seen without any lens image in the microscope illumination. However, in the intracameral illumination, the less bright light from the light pipe in the periphery and the lens fragments were seen more clearly. In a view of the patients' visual experience, oblique intracameral illumination caused less subjective photostress and was preferred over coaxial microscope illumination. Objective findings from the model-eye experiment correlated to the result of visual experience. Copyright © 2018 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Modulation of the pupil function of microscope objective lens for multifocal multi-photon microscopy using a spatial light modulator

NASA Astrophysics Data System (ADS)

Matsumoto, Naoya; Okazaki, Shigetoshi; Takamoto, Hisayoshi; Inoue, Takashi; Terakawa, Susumu

2014-02-01

We propose a method for high precision modulation of the pupil function of a microscope objective lens to improve the performance of multifocal multi-photon microscopy (MMM). To modulate the pupil function, we adopt a spatial light modulator (SLM) and place it at the conjugate position of the objective lens. The SLM can generate an arbitrary number of spots to excite the multiple fluorescence spots (MFS) at the desired positions and intensities by applying an appropriate computer-generated hologram (CGH). This flexibility allows us to control the MFS according to the photobleaching level of a fluorescent protein and phototoxicity of a specimen. However, when a large number of excitation spots are generated, the intensity distribution of the MFS is significantly different from the one originally designed due to misalignment of the optical setup and characteristics of the SLM. As a result, the image of a specimen obtained using laser scanning for the MFS has block noise segments because the SLM could not generate a uniform MFS. To improve the intensity distribution of the MFS, we adaptively redesigned the CGH based on the observed MFS. We experimentally demonstrate an improvement in the uniformity of a 10 × 10 MFS grid using a dye solution. The simplicity of the proposed method will allow it to be applied for calibration of MMM before observing living tissue. After the MMM calibration, we performed laser scanning with two-photon excitation to observe a real specimen without detecting block noise segments.

Miniature objective lens with variable focus for confocal endomicroscopy

PubMed Central

Kim, Minkyu; Kang, DongKyun; Wu, Tao; Tabatabaei, Nima; Carruth, Robert W.; Martinez, Ramses V; Whitesides, George M.; Nakajima, Yoshikazu; Tearney, Guillermo J.

2014-01-01

Spectrally encoded confocal microscopy (SECM) is a reflectance confocal microscopy technology that can rapidly image large areas of luminal organs at microscopic resolution. One of the main challenges for large-area SECM imaging in vivo is maintaining the same imaging depth within the tissue when patient motion and tissue surface irregularity are present. In this paper, we report the development of a miniature vari-focal objective lens that can be used in an SECM endoscopic probe to conduct adaptive focusing and to maintain the same imaging depth during in vivo imaging. The vari-focal objective lens is composed of an aspheric singlet with an NA of 0.5, a miniature water chamber, and a thin elastic membrane. The water volume within the chamber was changed to control curvature of the elastic membrane, which subsequently altered the position of the SECM focus. The vari-focal objective lens has a diameter of 5 mm and thickness of 4 mm. A vari-focal range of 240 μm was achieved while maintaining lateral resolution better than 2.6 μm and axial resolution better than 26 μm. Volumetric SECM images of swine esophageal tissues were obtained over the vari-focal range of 260 μm. SECM images clearly visualized cellular features of the swine esophagus at all focal depths, including basal cell nuclei, papillae, and lamina propria. PMID:25574443

National Register Testing of 42 Prehistoric Archeological Sites on Fort Hood, Texas: The 1996 Season

DTIC Science & Technology

1999-12-01

alluvium ca. 1100- 1000 B.P. The fact that flood stabilization, pedo - genesis, and accompanying increases in C4 395 National Register Testing at Fort...JVC TK-107OU Color Video Camera mounted on a Zeiss petrographic microscope using a 10X objective lens. The images were saved and imported into Adobe

Close, Closer, Closest: A Simple Activity to Inspire Keen Investigators in Your Classroom

ERIC Educational Resources Information Center

Farland, Donna

2008-01-01

As educators, we are always deciding what experiences we want to give students in order to achieve our goals of developing science process skills. One of the best ways of teaching about observation is described here. Using a hand lens and an illuminated pocket microscope, students observe an object at three different levels of…

Novel device for male infertility screening with single-ball lens microscope and smartphone.

PubMed

Kobori, Yoshitomo; Pfanner, Peter; Prins, Gail S; Niederberger, Craig

2016-09-01

To investigate the usefulness of a novel semen analysis device consisting of a single-ball lens microscope paired with a state-of-the-art smartphone equipped with a camera. Laboratory investigation. University research laboratory. A total of 50 semen samples obtained from volunteers were analyzed for count, concentration, and motility with an 0.8-mm ball lens and three types of smartphone. Comparisons were made with results obtained with a laboratory-based computer-assisted sperm analysis (CASA) system. None. Sperm concentration; sperm motility. Sperm concentration counted with a ball lens and each smartphone showed a very strong correlation with the CASA results. Likewise, sperm motility calculated with our device showed significant correlations to CASA. If eight spermatozoa or fewer were found on the field of view of an iPhone 6s, the semen specimens were considered to be below the lower reference limit for sperm concentration of World Health Organization 2010 guidelines (15 × 10(6) spermatozoa/mL). The sensitivity was 87.5%, and specificity was 90.9%. Smartphones have great potential to analyze semen because they are portable, contain excellent digital cameras, and can be easily attached to a microscope. A single-ball lens microscope is inexpensive and easy to use for acquiring digital microscopic movies. Given its small size and weight, the device can support testing for male fertility at home or in the field, making it much more convenient and economical than current practice. This single-ball lens microscope provides an easy solution for global users to rapidly screen for male infertility. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Development of three-dimensional tracking system using astigmatic lens method for microscopes

NASA Astrophysics Data System (ADS)

Kibata, Hiroki; Ishii, Katsuhiro

2017-07-01

We have developed a three-dimensional tracking system for microscopes. Using the astigmatic lens method and a CMOS image sensor, we realize a rapid detection of a target position in a wide range. We demonstrate a target tracking using the developed system.

Quantitative phase retrieval with arbitrary pupil and illumination

DOE PAGES

Claus, Rene A.; Naulleau, Patrick P.; Neureuther, Andrew R.; ...

2015-10-02

We present a general algorithm for combining measurements taken under various illumination and imaging conditions to quantitatively extract the amplitude and phase of an object wave. The algorithm uses the weak object transfer function, which incorporates arbitrary pupil functions and partially coherent illumination. The approach is extended beyond the weak object regime using an iterative algorithm. Finally, we demonstrate the method on measurements of Extreme Ultraviolet Lithography (EUV) multilayer mask defects taken in an EUV zone plate microscope with both a standard zone plate lens and a zone plate implementing Zernike phase contrast.

An automatic device for detection and classification of malaria parasite species in thick blood film.

PubMed

Kaewkamnerd, Saowaluck; Uthaipibull, Chairat; Intarapanich, Apichart; Pannarut, Montri; Chaotheing, Sastra; Tongsima, Sissades

2012-01-01

Current malaria diagnosis relies primarily on microscopic examination of Giemsa-stained thick and thin blood films. This method requires vigorously trained technicians to efficiently detect and classify the malaria parasite species such as Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) for an appropriate drug administration. However, accurate classification of parasite species is difficult to achieve because of inherent technical limitations and human inconsistency. To improve performance of malaria parasite classification, many researchers have proposed automated malaria detection devices using digital image analysis. These image processing tools, however, focus on detection of parasites on thin blood films, which may not detect the existence of parasites due to the parasite scarcity on the thin blood film. The problem is aggravated with low parasitemia condition. Automated detection and classification of parasites on thick blood films, which contain more numbers of parasite per detection area, would address the previous limitation. The prototype of an automatic malaria parasite identification system is equipped with mountable motorized units for controlling the movements of objective lens and microscope stage. This unit was tested for its precision to move objective lens (vertical movement, z-axis) and microscope stage (in x- and y-horizontal movements). The average precision of x-, y- and z-axes movements were 71.481 ± 7.266 μm, 40.009 ± 0.000 μm, and 7.540 ± 0.889 nm, respectively. Classification of parasites on 60 Giemsa-stained thick blood films (40 blood films containing infected red blood cells and 20 control blood films of normal red blood cells) was tested using the image analysis module. By comparing our results with the ones verified by trained malaria microscopists, the prototype detected parasite-positive and parasite-negative blood films at the rate of 95% and 68.5% accuracy, respectively. For classification performance, the thick blood films with Pv parasite was correctly classified with the success rate of 75% while the accuracy of Pf classification was 90%. This work presents an automatic device for both detection and classification of malaria parasite species on thick blood film. The system is based on digital image analysis and featured with motorized stage units, designed to easily be mounted on most conventional light microscopes used in the endemic areas. The constructed motorized module could control the movements of objective lens and microscope stage at high precision for effective acquisition of quality images for analysis. The analysis program could accurately classify parasite species, into Pf or Pv, based on distribution of chromatin size.

High resolution computational on-chip imaging of biological samples using sparsity constraint (Conference Presentation)

NASA Astrophysics Data System (ADS)

Rivenson, Yair; Wu, Chris; Wang, Hongda; Zhang, Yibo; Ozcan, Aydogan

2017-03-01

Microscopic imaging of biological samples such as pathology slides is one of the standard diagnostic methods for screening various diseases, including cancer. These biological samples are usually imaged using traditional optical microscopy tools; however, the high cost, bulkiness and limited imaging throughput of traditional microscopes partially restrict their deployment in resource-limited settings. In order to mitigate this, we previously demonstrated a cost-effective and compact lens-less on-chip microscopy platform with a wide field-of-view of >20-30 mm^2. The lens-less microscopy platform has shown its effectiveness for imaging of highly connected biological samples, such as pathology slides of various tissue samples and smears, among others. This computational holographic microscope requires a set of super-resolved holograms acquired at multiple sample-to-sensor distances, which are used as input to an iterative phase recovery algorithm and holographic reconstruction process, yielding high-resolution images of the samples in phase and amplitude channels. Here we demonstrate that in order to reconstruct clinically relevant images with high resolution and image contrast, we require less than 50% of the previously reported nominal number of holograms acquired at different sample-to-sensor distances. This is achieved by incorporating a loose sparsity constraint as part of the iterative holographic object reconstruction. We demonstrate the success of this sparsity-based computational lens-less microscopy platform by imaging pathology slides of breast cancer tissue and Papanicolaou (Pap) smears.

Three-dimensional microscopic tomographic imagings of the cataract in a human lens in vivo

NASA Astrophysics Data System (ADS)

Masters, Barry R.

1998-10-01

The problem of three-dimensional visualization of a human lens in vivo has been solved by a technique of volume rendering a transformed series of 60 rotated Scheimpflug (a dual slit reflected light microscope) digital images. The data set was obtained by rotating the Scheimpflug camera about the optic axis of the lens in 3 degree increments. The transformed set of optical sections were first aligned to correct for small eye movements, and then rendered into a volume reconstruction with volume rendering computer graphics techniques. To help visualize the distribution of lens opacities (cataracts) in the living, human lens the intensity of light scattering was pseudocolor coded and the cataract opacities were displayed as a movie.

Fast two-layer two-photon imaging of neuronal cell populations using an electrically tunable lens

PubMed Central

Grewe, Benjamin F.; Voigt, Fabian F.; van ’t Hoff, Marcel; Helmchen, Fritjof

2011-01-01

Functional two-photon Ca2+-imaging is a versatile tool to study the dynamics of neuronal populations in brain slices and living animals. However, population imaging is typically restricted to a single two-dimensional image plane. By introducing an electrically tunable lens into the excitation path of a two-photon microscope we were able to realize fast axial focus shifts within 15 ms. The maximum axial scan range was 0.7 mm employing a 40x NA0.8 water immersion objective, plenty for typically required ranges of 0.2–0.3 mm. By combining the axial scanning method with 2D acousto-optic frame scanning and random-access scanning, we measured neuronal population activity of about 40 neurons across two imaging planes separated by 40 μm and achieved scan rates up to 20–30 Hz. The method presented is easily applicable and allows upgrading of existing two-photon microscopes for fast 3D scanning. PMID:21750778

Experimental realization of the Ehrenberg-Siday thought experiment

NASA Astrophysics Data System (ADS)

Pozzi, Giulio; Boothroyd, Chris B.; Tavabi, Amir H.; Yücelen, Emrah; Dunin-Borkowski, Rafal E.; Frabboni, Stefano; Gazzadi, Gian Carlo

2016-02-01

In 1949, at the end of a paper dedicated to the concept of the refractive index in electron optics, Ehrenberg and Siday noted that wave-optical effects will arise from an isolated magnetic field even when the rays themselves travel in magnetic-field-free space. They proposed a two-slit experiment, in which a magnetic flux is enclosed between interfering electron beams. Now, through access to modern nanotechnology tools, we used a focused ion beam to open two nanosized slits in a gold-coated silicon nitride membrane and focused electron beam induced deposition to fabricate a thin magnetic bar between the two slits. We then performed Fraunhofer experiments in a transmission electron microscope equipped with a field emission gun and a Lorentz lens. By tilting the specimen in the objective lens field of the electron microscope, the magnetization of the bar could be reversed and the corresponding change in the phase of the electron wave observed directly in the form of a shift in the interference fringe pattern.

Use of a microscope-mounted wide-angle point of view camera to record optimal hand position in ocular surgery.

PubMed

Gooi, Patrick; Ahmed, Yusuf; Ahmed, Iqbal Ike K

2014-07-01

We describe the use of a microscope-mounted wide-angle point-of-view camera to record optimal hand positions in ocular surgery. The camera is mounted close to the objective lens beneath the surgeon's oculars and faces the same direction as the surgeon, providing a surgeon's view. A wide-angle lens enables viewing of both hands simultaneously and does not require repositioning the camera during the case. Proper hand positioning and instrument placement through microincisions are critical for effective and atraumatic handling of tissue within the eye. Our technique has potential in the assessment and training of optimal hand position for surgeons performing intraocular surgery. It is an innovative way to routinely record instrument and operating hand positions in ophthalmic surgery and has minimal requirements in terms of cost, personnel, and operating-room space. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Analysis of thick brain sections by obverse-reverse computer microscopy: application of a new, high clarity Golgi-Nissl stain.

PubMed

Glaser, E M; Van der Loos, H

1981-08-01

Exceptionally clear Golgi-Nissl sections of 300 micron thickness have been morphometrically studied by light microscopy using oil immersion objectives. The clarity results from a new variation of a staining procedure that combines Golgi and Nissl images in one section. A viewing technique has been developed that permits a histologic preparation to be examined from its obverse (or normally viewed) side and its reverse (or under) side. The technique was designed for use with a computer microscope but can be employed with any light microscope whose stage position can be measured within 100 micron. Sections thicker than 300 micron can be studied dependent on the working distance of the objective lens, provided that the clarity of the material permits it.

A lab-on-phone instrument with varifocal microscope via a liquid-actuated aspheric lens (LAL)

PubMed Central

Fuh, Yiin-Kuen; Lai, Zheng-Hong; Kau, Li-Han; Huang, Hung-Jui

2017-01-01

In this paper, we introduce a novel concept of liquid-actuated aspheric lens (LAL) with a built-in aspheric polydimethylsiloxane lens (APL) to enable the design of compact optical systems with varifocal microscopic imaging. The varifocal lens module consists of a sandwiched structures such as 3d printed syringe pump functionally serves as liquid controller. Other key components include two acrylic cylinders, a rigid separator, a APL/membrane composite (APLMC) embedded PDMS membrane. In functional operation, the fluidic controller was driven to control the pressure difference and ALPMC deformation. The focal length can be changed through the pressure difference. This is achieved by the adjustment of volume change of injected liquid such that a widely tunable focal length. The proposed LAL can transform to 3 modes: microscopic mode (APLMC only), convex-concave mode and biconcave mode. It is noticeable that LAL in the operation of microscopic mode is tunable in focus via the actuation of APLMC (focal length is from 4.3 to 2.3 mm and magnification 50X) and can rival the images quality of commercial microscopes. A new lab-on-phone device is economically feasible and functionally versatile to offer a great potential in the point of care applications. PMID:28650971

Design, assembly, and metrology of an oil-immersion microscope objective with long working distance

NASA Astrophysics Data System (ADS)

Peng, Wei-Jei; Lin, Wen-Lung; Kuo, Hui-Jean; Ho, Cheng-Fang; Hsu, Wei-Yao

2016-10-01

The design, tolerance sensitivity reduction, assembly, and optical bench test for an oil-immersion microscope objective with long working distance employed in a lattice light-sheet microscope is presented in this paper. In this application, the orthogonal excitation and detection objectives are dipped in an oil medium. The excitation objective focuses the incident laser beam to generate fluorescence on specimen for collecting by detection objective. The excitation objective is custom-designed to meet the requirement specification such as oil-immersion, the long working distance, and numerical aperture (NA) of 0.5, etc. To produce an acceptable point spread function (PSF) for effective excitation, the performance of the objective needs to be close to diffraction limit. Because the tolerance of the modulation transfer function (MTF) is more and more sensitive at higher spatial frequency, it is extremely critical to keep the performance after manufacture. Consequently, an insensitive optical design is very important for relaxing tolerance. We compare the design with and without tolerance sensitivity reduction, and the as-built MTF shows the result. Furthermore, the method for sensitivity reduction is presented. The opto-mechanical design and assembly method are also discussed. Eventually, the objective with five spherical lenses was fabricated. In optical bench test, the depth of the oil is sensitive to MTF, and it leads to the complicated adjustment. For solving this issue, we made an index-matching lens to replace oil for measurement easily. Finally, the measured MTF of the excitation objective can accomplish the requirement specification and successfully employed in a lattice light-sheet microscope.

Optical polymers for laser medical applications

NASA Astrophysics Data System (ADS)

Sultanova, Nina G.; Kasarova, Stefka N.; Nikolov, Ivan D.

2016-01-01

In medicine, optical polymers are used not only in ophthalmology but in many laser surgical, diagnostic and therapeutic systems. The application in lens design is determined by their refractive and dispersive properties in the considered spectral region. We have used different measuring techniques to obtain precise refractometric data in the visible and near-infrared spectral regions. Dispersive, thermal and other important optical characteristics of polymers have been studied. Design of a plastic achromatic objective, used in a surgical stereo-microscope at 1064 nm laser wavelength, is accomplished. Geometrical and wavefront aberrations are calculated. Another example of application of polymers is the designed all-mirror apochromatic micro-lens, intended for superluminescent diode fiber coupling in medical systems.

Effective increase in beam emittance by phase-space expansion using asymmetric Bragg diffraction.

PubMed

Chu, Chia-Hung; Tang, Mau-Tsu; Chang, Shih-Lin

2015-08-24

We propose an innovative method to extend the utilization of the phase space downstream of a synchrotron light source for X-ray transmission microscopy. Based on the dynamical theory of X-ray diffraction, asymmetrically cut perfect crystals are applied to reshape the position-angle-wavelength space of the light source, by which the usable phase space of the source can be magnified by over one hundred times, thereby "phase-space-matching" the source with the objective lens of the microscope. The method's validity is confirmed using SHADOW code simulations, and aberration through an optical lens such as a Fresnel zone plate is examined via matrix optics for nano-resolution X-ray images.

Eyecup scope—optical recordings of light stimulus-evoked fluorescence signals in the retina

PubMed Central

Hausselt, Susanne E.; Breuninger, Tobias; Castell, Xavier; Denk, Winfried; Margolis, David J.; Detwiler, Peter B.

2009-01-01

Dendritic signals play an essential role in processing visual information in the retina. To study them in neurites too small for electrical recording, we developed an instrument that combines a multi-photon (MP) microscope with a through-the-objective high-resolution visual stimulator. An upright microscope was designed that uses the objective lens for both MP imaging and delivery of visual stimuli to functionally intact retinal explants or eyecup preparations. The stimulator consists of a miniature liquid-crystal-on-silicon display coupled into the optical path of an infrared-excitation laser-scanning microscope. A pair of custom-made dichroic filters allows light from the excitation laser and three spectral bands (‘colors’) from the stimulator to reach the retina, leaving two intermediate bands for fluorescence imaging. Special optics allow displacement of the stimulator focus relative to the imaging focus. Spatially resolved changes in calcium-indicator fluorescence in response to visual stimuli were recorded in dendrites of different types of mammalian retinal neurons. PMID:19023590

An orientation-independent DIC microscope allows high resolution imaging of epithelial cell migration and wound healing in a cnidarian model.

PubMed

Malamy, J E; Shribak, M

2018-06-01

Epithelial cell dynamics can be difficult to study in intact animals or tissues. Here we use the medusa form of the hydrozoan Clytia hemisphaerica, which is covered with a monolayer of epithelial cells, to test the efficacy of an orientation-independent differential interference contrast microscope for in vivo imaging of wound healing. Orientation-independent differential interference contrast provides an unprecedented resolution phase image of epithelial cells closing a wound in a live, nontransgenic animal model. In particular, the orientation-independent differential interference contrast microscope equipped with a 40x/0.75NA objective lens and using the illumination light with wavelength 546 nm demonstrated a resolution of 460 nm. The repair of individual cells, the adhesion of cells to close a gap, and the concomitant contraction of these cells during closure is clearly visualized. © 2018 The Authors Journal of Microscopy © 2018 Royal Microscopical Society.

[Improvement of the microcinematography technic for the study of cell cycles].

PubMed

Gueulette, J; Beauduin, M; Grégoire, V; Van Dorpe, J C; Wambersie, A

1984-10-01

An improvement of time-lapse microcinematography technique is described. It consists in directly printing the time on the microscopical frame, at the moment of the shooting. The time (digital watch), as well as other relevant parameters (temperature etc.) are displayed on a "parameter board", the image of which is encrusted into the microscopical frame by means of an auxiliary two-component lens system. These lenses (current type of microscopical and photographical objectives) are centered on an axis perpendicular to the microscope-camera axis and provide a reduced image of the "parameter board", which is projected on the film edge after deflection by a 45 degree mirror. The latter (aluminized perspex sheet) is located above the photographical eyepiece; it is pierced at the place of the eyepoint in order to give way to the light rays coming out of the cellular culture.

A simple optical tweezers for trapping polystyrene particles

NASA Astrophysics Data System (ADS)

Shiddiq, Minarni; Nasir, Zulfa; Yogasari, Dwiyana

2013-09-01

Optical tweezers is an optical trap. For decades, it has become an optical tool that can trap and manipulate any particle from the very small size like DNA to the big one like bacteria. The trapping force comes from the radiation pressure of laser light which is focused to a group of particles. Optical tweezers has been used in many research areas such as atomic physics, medical physics, biophysics, and chemistry. Here, a simple optical tweezers has been constructed using a modified Leybold laboratory optical microscope. The ocular lens of the microscope has been removed for laser light and digital camera accesses. A laser light from a Coherent diode laser with wavelength λ = 830 nm and power 50 mW is sent through an immersion oil objective lens with magnification 100 × and NA 1.25 to a cell made from microscope slides containing polystyrene particles. Polystyrene particles with size 3 μm and 10 μm are used. A CMOS Thorlabs camera type DCC1545M with USB Interface and Thorlabs camera lens 35 mm are connected to a desktop and used to monitor the trapping and measure the stiffness of the trap. The camera is accompanied by camera software which makes able for the user to capture and save images. The images are analyzed using ImageJ and Scion macro. The polystyrene particles have been trapped successfully. The stiffness of the trap depends on the size of the particles and the power of the laser. The stiffness increases linearly with power and decreases as the particle size larger.

Volumetric HiLo microscopy employing an electrically tunable lens.

PubMed

Philipp, Katrin; Smolarski, André; Koukourakis, Nektarios; Fischer, Andreas; Stürmer, Moritz; Wallrabe, Ulrike; Czarske, Jürgen W

2016-06-27

Electrically tunable lenses exhibit strong potential for fast motion-free axial scanning in a variety of microscopes. However, they also lead to a degradation of the achievable resolution because of aberrations and misalignment between illumination and detection optics that are induced by the scan itself. Additionally, the typically nonlinear relation between actuation voltage and axial displacement leads to over- or under-sampled frame acquisition in most microscopic techniques because of their static depth-of-field. To overcome these limitations, we present an Adaptive-Lens-High-and-Low-frequency (AL-HiLo) microscope that enables volumetric measurements employing an electrically tunable lens. By using speckle-patterned illumination, we ensure stability against aberrations of the electrically tunable lens. Its depth-of-field can be adjusted a-posteriori and hence enables to create flexible scans, which compensates for irregular axial measurement positions. The adaptive HiLo microscope provides an axial scanning range of 1 mm with an axial resolution of about 4 μm and sub-micron lateral resolution over the full scanning range. Proof of concept measurements at home-built specimens as well as zebrafish embryos with reporter gene-driven fluorescence in the thyroid gland are shown.

The trajectories of secondary electrons in the scanning electron microscope.

PubMed

Konvalina, Ivo; Müllerová, Ilona

2006-01-01

Three-dimensional simulations of the trajectories of secondary electrons (SE) in the scanning electron microscope have been performed for plenty of real configurations of the specimen chamber, including all its basic components. The primary purpose was to evaluate the collection efficiency of the Everhart-Thornley detector of SE and to reveal fundamental rules for tailoring the set-ups in which efficient signal acquisition can be expected. Intuitive realizations about the easiness of attracting the SEs towards the biased front grid of the detector have shown themselves likely as false, and all grounded objects in the chamber have been proven to influence the spatial distribution of the signal-extracting field. The role of the magnetic field penetrating from inside the objective lens is shown to play an ambiguous role regarding possible support for the signal collection.

Camera, handlens, and microscope optical system for imaging and coupled optical spectroscopy

NASA Technical Reports Server (NTRS)

Mungas, Greg S. (Inventor); Boynton, John (Inventor); Sepulveda, Cesar A. (Inventor); Nunes de Sepulveda, legal representative, Alicia (Inventor); Gursel, Yekta (Inventor)

2012-01-01

An optical system comprising two lens cells, each lens cell comprising multiple lens elements, to provide imaging over a very wide image distance and within a wide range of magnification by changing the distance between the two lens cells. An embodiment also provides scannable laser spectroscopic measurements within the field-of-view of the instrument.

Camera, handlens, and microscope optical system for imaging and coupled optical spectroscopy

NASA Technical Reports Server (NTRS)

Mungas, Greg S. (Inventor); Boynton, John (Inventor); Sepulveda, Cesar A. (Inventor); Nunes de Sepulveda, Alicia (Inventor); Gursel, Yekta (Inventor)

2011-01-01

An optical system comprising two lens cells, each lens cell comprising multiple lens elements, to provide imaging over a very wide image distance and within a wide range of magnification by changing the distance between the two lens cells. An embodiment also provides scannable laser spectroscopic measurements within the field-of-view of the instrument.

Optimal resolution in Fresnel incoherent correlation holographic fluorescence microscopy

PubMed Central

Brooker, Gary; Siegel, Nisan; Wang, Victor; Rosen, Joseph

2011-01-01

Fresnel Incoherent Correlation Holography (FINCH) enables holograms and 3D images to be created from incoherent light with just a camera and spatial light modulator (SLM). We previously described its application to microscopic incoherent fluorescence wherein one complex hologram contains all the 3D information in the microscope field, obviating the need for scanning or serial sectioning. We now report experiments which have led to the optimal optical, electro-optic, and computational conditions necessary to produce holograms which yield high quality 3D images from fluorescent microscopic specimens. An important improvement from our previous FINCH configurations capitalizes on the polarization sensitivity of the SLM so that the same SLM pixels which create the spherical wave simulating the microscope tube lens, also pass the plane waves from the infinity corrected microscope objective, so that interference between the two wave types at the camera creates a hologram. This advance dramatically improves the resolution of the FINCH system. Results from imaging a fluorescent USAF pattern and a pollen grain slide reveal resolution which approaches the Rayleigh limit by this simple method for 3D fluorescent microscopic imaging. PMID:21445140

Two-Photon Fluorescence Microscope for Microgravity Research

NASA Technical Reports Server (NTRS)

Fischer, David G.; Zimmerli, Gregory A.; Asipauskas, Marius

2005-01-01

A two-photon fluorescence microscope has been developed for the study of biophysical phenomena. Two-photon microscopy is a novel form of laser-based scanning microscopy that enables three-dimensional imaging without many of the problems inherent in confocal microscopy. Unlike one-photon optical microscopy, two-photon microscopy utilizes the simultaneous nonlinear absorption of two near-infrared photons. However, the efficiency of two-photon absorption is much lower than that of one-photon absorption, so an ultra-fast pulsed laser source is typically employed. On the other hand, the critical energy threshold for two-photon absorption leads to fluorophore excitation that is intrinsically localized to the focal volume. Consequently, two-photon microscopy enables optical sectioning and confocal performance without the need for a signal-limiting pinhole. In addition, there is a reduction (relative to one-photon optical microscopy) in photon-induced damage because of the longer excitation wavelength. This reduction is especially advantageous for in vivo studies. Relative to confocal microscopy, there is also a reduction in background fluorescence, and, because of a reduction in Rayleigh scattering, there is a 4 increase of penetration depth. The prohibitive cost of a commercial two-photon fluorescence-microscope system, as well as a need for modularity, has led to the construction of a custom-built system (see Figure 1). This system includes a coherent mode-locked titanium: sapphire laser emitting 120-fs-duration pulses at a repetition rate of 80 MHz. The pulsed laser has an average output power of 800 mW and a wavelength tuning range of 700 to 980 nm, enabling the excitation of a variety of targeted fluorophores. The output from the laser is attenuated, spatially filtered, and then directed into a confocal scanning head that has been modified to provide for side entry of the laser beam. The laser output coupler has been replaced with a dichroic filter that reflects the longer-wavelength excitation light and passes the shorter-wavelength fluorescence light. Also, the confocal pinhole has been removed to increase the signal strength. The laser beam is scanned by a twoperpendicular- axis pair of galvanometer mirrors through a pupil transfer lens into the side port of an inverted microscope. Finally, the beam is focused by a 63-magnification, 1.3-numerical- aperture oil-immersion objective lens onto a specimen. The pupil transfer lens serves to match the intermediate image planes of the scanning head and the microscope, and its location is critical. In order to maximize the quality of the image, (that is, the point spread function of the objective lens for all scan positions), the entire system was modeled in optical-design software, and the various free design parameters (the parameters of the spatial-filter components as well as the separations of all of the system components) were determined through an iterative optimization process. A modular design was chosen to facilitate access to the optical train for future fluorescence correlation spectroscopy and fluorescence-lifetime experiments.

Interferometric scanning optical microscope for surface characterization.

PubMed

Offside, M J; Somekh, M G

1992-11-01

A phase-sensitive scanning optical microscope is described that can measure surface height changes down to 0.1 nm. This is achieved by using two heterodyne Michelson interferometers in parallel. One interferometer probes the sample with a tightly focused beam, and the second has a collimated beam that illuminates a large area of the surface, providing a large area on sample reference. This is facilitated by using a specially constructed objective lens that permits the relative areas illuminated by the two probe beams to be varied both arbitrarily and independently, thus ensuring an accurate absolute phase measurement. We subtracted the phase outputs from each interferometer to provide the sample phase information, canceling the phase noise resulting from microphonics in the process. Results from a prototype version of the microscope are presented that demonstrate the advantages of the system over existing techniques.

Depth of focus extended microscope configuration for imaging of incorporated groups of molecules, DNA constructs and clusters inside bacterial cells

NASA Astrophysics Data System (ADS)

Fessl, Tomas; Ben-Yaish, Shai; Vacha, Frantisek; Adamec, Frantisek; Zalevsky, Zeev

2009-07-01

Imaging of small objects such as single molecules, DNA clusters and single bacterial cells is problematic not only due to the lateral resolution that is obtainable in currently existing microscopy but also, and as much fundamentally limiting, due to the lack of sufficient axial depth of focus to have the full object focused simultaneously. Extension in depth of focus is helpful also for single molecule steady state FRET measurements. In this technique it is crucial to obtain data from many well focused molecules, which are often located in different axial depths. In this paper we present the implementation of an all-optical and a real time technique of extension in the depth of focus that may be incorporated in any high NA microscope system and to be used for the above mentioned applications. We demonstrate experimentally how after the integration of special optical element in high NA 100× objective lens of a single molecule imaging microscope system, the depth of focus is significantly improved while maintaining the same lateral resolution in imaging applications of incorporated groups of molecules, DNA constructs and clusters inside bacterial cells.

A light sheet confocal microscope for image cytometry with a variable linear slit detector

NASA Astrophysics Data System (ADS)

Hutcheson, Joshua A.; Khan, Foysal Z.; Powless, Amy J.; Benson, Devin; Hunter, Courtney; Fritsch, Ingrid; Muldoon, Timothy J.

2016-03-01

We present a light sheet confocal microscope (LSCM) capable of high-resolution imaging of cell suspensions in a microfluidic environment. In lieu of conventional pressure-driven flow or mechanical translation of the samples, we have employed a novel method of fluid transport, redox-magnetohydrodynamics (redox-MHD). This method achieves fluid motion by inducing a small current into the suspension in the presence of a magnetic field via electrodes patterned onto a silicon chip. This on-chip transportation requires no moving parts, and is coupled to the remainder of the imaging system. The microscopy system comprises a 450 nm diode 20 mW laser coupled to a single mode fiber and a cylindrical lens that converges the light sheet into the back aperture of a 10x, 0.3 NA objective lens in an epi-illumination configuration. The emission pathway contains a 150 mm tube lens that focuses the light onto the linear sensor at the conjugate image plane. The linear sensor (ELiiXA+ 8k/4k) has three lateral binning modes which enables variable detection aperture widths between 5, 10, or 20 μm, which can be used to vary axial resolution. We have demonstrated redox-MHD-enabled light sheet microscopy in suspension of fluorescent polystyrene beads. This approach has potential as a high-throughput image cytometer with myriad cellular diagnostic applications.

Martian Microscope

NASA Technical Reports Server (NTRS)

2004-01-01

The microscopic imager (circular device in center) is in clear view above the surface at Meridiani Planum, Mars, in this approximate true-color image taken by the panoramic camera on the Mars Exploration Rover Opportunity. The image was taken on the 9th sol of the rover's journey. The microscopic imager is located on the rover's instrument deployment device, or arm. The arrow is pointing to the lens of the instrument. Note the dust cover, which flips out to the left of the lens, is open. This approximated color image was created using the camera's violet and infrared filters as blue and red.

Application of an optical interferometer for measuring the surface contour of micro-components

NASA Astrophysics Data System (ADS)

Wang, S. H.; Tay, C. J.

2006-04-01

The application of an optical interferometric system using a Mireau objective to measure the surface profile of micro-components is described. The proposed system produces a uniform monochromatic illumination over the test area and introduces an interference fringe pattern localized near the test surface. Both the interference fringes and the 2D image of the test surface can be focused by an infinity microscope system consisting of a Mireau objective and a tube lens. A piezoelectric transducer (PZT) attached to the Mireau objective can move precisely along the optical axis of the objective. This enables the implementation of phase-shifting interferometry without changing the focus of a CCD sensor as the combination of the Mireau objective and the tube lens provides a depth of focus which is deep in comparison to the phase-shifting step. Experimental results from surface profilometry of the protrusion/undercut of a polished fibre within an optical connector and of the curved surface of a micromirror demonstrate that features in the order of nanometres are measurable. Measurements on standard blocks also show that the accuracy of the proposed system is comparable to an existing commercial white-light interferometer and a stylus profilometer.

Chromatic Properties of Index of Refraction Gradients in Glass.

NASA Astrophysics Data System (ADS)

Ryan-Howard, Danette Patrice

The chromatic properties of index of refraction gradients have been predicted theoretically and verified experimentally. The use of these materials in the design of color corrected optical systems has been investigated and confirmed by the evaluation of two fabricated lenses. A model for the chromatic properties of gradient index materials has been developed. The index of refraction is calculated based on the composition of the material. Since the index of refraction and the conventional Abbe number change as a function of the composition of the glass, a gradient Abbe number and a partial dispersion are defined. Analysis of combinations of ion exchange pairs and glasses result in a wide range of gradient Abbe numbers and partial dispersions. These ranges can be further extended by using glasses which contain more than one exchange ion or by using mixed salt baths. The chromatic properties were measured with a multiple wavelength A.C. interferometer. The gradient Abbe numbers and partial dispersions for a number of samples were calculated. Evaluation of the samples showed that the index and dispersion data correlated well with that predicted by the model. Thin lens formulae for the paraxial axial color and secondary spectrum of a radial gradient singlet with curves were examined. The design of a single element 10x microscope objective verified the applicability of these formulae. The design of a two element 40x microscope objective showed that a six element diffraction limited 40x objective can be replaced with a two element system composed of one homogeneous lens and one gradient lens without sacrificing either monochromatic performance or color correction. A previously fabricated axial gradient collimator and a fabricated Wood element were evaluated. Correlation of the directly measured quantities, paraxial axial color, secondary spectrum and spherochromatism with the values predicted by the model verified that the predicted superior performance of gradient-index lenses can be obtained.

Images of intravitreal objects projected onto posterior surface of model eye.

PubMed

Kawamura, Ryosuke; Shinoda, Kei; Inoue, Makoto; Noda, Toru; Ohnuma, Kazuhiko; Hirakata, Akito

2013-11-01

To try to recreate the images reported by patients during vitreous surgery in a model eye. A fluid-filled model eye with a posterior frosted translucent surface which corresponded to the retina was used. Three holes were made in the model eye through which an endoillumination pipe and intraocular forceps could be inserted. A thin plastic sheet simulating an epiretinal membrane and an intraocular lens (IOL) simulating a dislocated IOL were placed on the retina. The images falling on the posterior surface were photographed from the rear. The images seen through the surgical microscope were also recorded. The images from the rear were mirror images of those seen through the surgical microscope. Intraocular instruments were seen as black shafts from the rear. When the plastic sheet was picked up, the tip of the forceps was seen more sharply on the posterior surface. The images of the dislocated IOL from the posterior were similar to that seen through the surgical microscope, including the yellow optics and blue haptics. Intravitreal objects can form images on the surface of a model eye. Objects located closer to the surface are seen more sharply, and the colour of the objects can be identified. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Micro axial tomography: A miniaturized, versatile stage device to overcome resolution anisotropy in fluorescence light microscopy

NASA Astrophysics Data System (ADS)

Staier, Florian; Eipel, Heinz; Matula, Petr; Evsikov, Alexei V.; Kozubek, Michal; Cremer, Christoph; Hausmann, Michael

2011-09-01

With the development of novel fluorescence techniques, high resolution light microscopy has become a challenging technique for investigations of the three-dimensional (3D) micro-cosmos in cells and sub-cellular components. So far, all fluorescence microscopes applied for 3D imaging in biosciences show a spatially anisotropic point spread function resulting in an anisotropic optical resolution or point localization precision. To overcome this shortcoming, micro axial tomography was suggested which allows object tilting on the microscopic stage and leads to an improvement in localization precision and spatial resolution. Here, we present a miniaturized device which can be implemented in a motor driven microscope stage. The footprint of this device corresponds to a standard microscope slide. A special glass fiber can manually be adjusted in the object space of the microscope lens. A stepwise fiber rotation can be controlled by a miniaturized stepping motor incorporated into the device. By means of a special mounting device, test particles were fixed onto glass fibers, optically localized with high precision, and automatically rotated to obtain views from different perspective angles under which distances of corresponding pairs of objects were determined. From these angle dependent distance values, the real 3D distance was calculated with a precision in the ten nanometer range (corresponding here to an optical resolution of 10-30 nm) using standard microscopic equipment. As a proof of concept, the spindle apparatus of a mature mouse oocyte was imaged during metaphase II meiotic arrest under different perspectives. Only very few images registered under different rotation angles are sufficient for full 3D reconstruction. The results indicate the principal advantage of the micro axial tomography approach for many microscopic setups therein and also those of improved resolutions as obtained by high precision localization determination.

Sharing of secondary electrons by in-lens and out-lens detector in low-voltage scanning electron microscope equipped with immersion lens.

PubMed

Kumagai, Kazuhiro; Sekiguchi, Takashi

2009-03-01

To understand secondary electron (SE) image formation with in-lens and out-lens detector in low-voltage scanning electron microscopy (LV-SEM), we have evaluated SE signals of an in-lens and an out-lens detector in LV-SEM. From the energy distribution spectra of SEs with various boosting voltages of the immersion lens system, we revealed that the electrostatic field of the immersion lens mainly collects electrons with energy lower than 40eV, acting as a low-pass filter. This effect is also observed as a contrast change in LV-SEM images taken by in-lens and out-lens detectors.

Ultrastructural effects of silicone oil on the clear crystalline lens of the human eye.

PubMed

Soliman, Wael; Sharaf, Mohamed; Abdelazeem, Khaled; El-Gamal, Dalia; Nafady, Allam

2018-03-01

To evaluate light and electron microscopic changes of the anterior capsule and its epithelium after clear lens extraction of vitrectomized myopic eyes with silicone oil tamponade. This prospective, controlled, non-randomized, interventional study included 20 anterior lens capsular specimens that were excised during combined clear lens extraction and silicone oil removal from previously vitrectomized highly myopic patients with silicone oil tamponade for previous retinal detachment surgeries. The specimens were examined via light microscopy and electron microscopy and compared with 20 anterior capsule specimens removed during clear lens extraction of non-vitrectomized highly myopic eyes. Light microscopic examination of clear lens anterior capsule specimens of vitrectomized myopic eyes filled with silicone oil showed relatively more flat cells with irregular outline of lens' epithelial cells with wide intercellular spaces, deeply stained nuclei, and multiple intracytoplasmic vacuoles. Scanning electron microscopy revealed collagenous surfaces filled with multiple pits, depressions, and abnormal deposits. Transmission electron microscopy revealed lens epithelial cells with apoptotic changes, many cytoplasmic vacuoles, and filopodia-like protrusions between lens epithelial cells and the capsule. Epithelial proliferation and multilayering were also observed. silicone oil may play a role in the development of apoptotic and histopathological changes in clear lens epithelial cells. Clarity of the lens at the time of silicone oil removal does not indicate an absence of cataractous changes. We found justification of combined clear lens extraction and silicone oil removal or combined phacovitrectomy when silicone oil injection is planned, but further long-term studies with larger patient groups are required.

Imaging of blood antigen distribution on blood cells by thermal lens microscopy

NASA Astrophysics Data System (ADS)

Kimura, Hiroko; Sekiguchi, Kazuya; Nagao, Fumiko; Mukaida, Masahiro; Kitamori, Takehiko; Sawada, Tsuguo

2000-05-01

Blood group antigens on a cell were measured by a new microscopic method, i.e. thermal lens microscopy which involves spectrometry using a laser-induced thermal-lens effect. The blood group antigen was immunologically stained using antibody labeled with colloidal gold. Human leukocyte antigens (HLA) on lymphocytes and mononuclear leukocytes were observed by the thermal lens microscope, and Lewis blood group antigens on erythrocytes and polymorphonuclear leukocytes were also observed. The antigen distribution on each cell-surface was imaged using this technique. In spite of convex surface of living cells, colloidal gold was correctly quantified by adjusting the deviation of the focal point of the probe laser by the phase of the signal. In the measurement of leukocyte antigens, antigens of HLA-A, -B, -C loci on the lymphocytes were identified and quantitated by using a single cell. The image of HLA-A, -B, -C antigen distribution on a mononuclear leukocyte was obtained. In the measurement of erythrocyte antigens, a small quantity of Lewis antigens was detected on the cord erythrocytes. Localized small quantities of membrane antigens are better quantitated without extraction or cytolysis. Our thermal lens microscope is a powerful and highly sensitive analytical tool for detecting and quantitating localized antigens in single cells and/or cell-surface-associated molecules.

The application of digital image plane holography technology to identify Chinese herbal medicine

NASA Astrophysics Data System (ADS)

Wang, Huaying; Guo, Zhongjia; Liao, Wei; Zhang, Zhihui

2012-03-01

In this paper, the imaging technology of digital image plane holography to identify the Chinese herbal medicine is studied. The optical experiment system of digital image plane holography which is the special case of pre-magnification digital holography was built. In the record system, one is an object light by using plane waves which illuminates the object, and the other one is recording hologram by using spherical light wave as reference light. There is a Micro objective lens behind the object. The second phase factor which caus ed by the Micro objective lens can be eliminated by choosing the proper position of the reference point source when digital image plane holography is recorded by spherical light. In this experiment, we use the Lygodium cells and Onion cells as the object. The experiment results with Lygodium cells and Onion cells show that digital image plane holography avoid the process of finding recording distance by using auto-focusing approach, and the phase information of the object can be reconstructed more accurately. The digital image plane holography is applied to the microscopic imaging of cells more effectively, and it is suit to apply for the identify of Chinese Herbal Medicine. And it promotes the application of digital holographic in practice.

Fabrication of embedded microball lens in PMMA with high repetition rate femtosecond fiber laser.

PubMed

Zheng, Chong; Hu, Anming; Li, Ruozhou; Bridges, Denzel; Chen, Tao

2015-06-29

Embedded microball lenses with superior optical properties function as convex microball lens (VMBL) and concave microball lens (CMBL) were fabricated inside a PMMA substrate with a high repetition rate femtosecond fiber laser. The VMBL was created by femtosecond laser-induced refractive index change, while the CMBL was fabricated due to the heat accumulation effect of the successive laser pulses irradiation at a high repetition rate. The processing window for both types of the lenses was studied and optimized, and the optical properties were also tested by imaging a remote object with an inverted microscope. In order to obtain the microball lenses with adjustable focal lengths and suppressed optical aberration, a shape control method was thus proposed and examined with experiments and ZEMAX® simulations. Applying the optimized fabrication conditions, two types of the embedded microball lenses arrays were fabricated and then tested with imaging experiments. This technology allows the direct fabrication of microlens inside transparent bulk polymer material which has great application potential in multi-function integrated microfluidic devices.

Clear lens phacoemulsification in Alport syndrome: refractive results and electron microscopic analysis of the anterior lens capsule.

PubMed

Bayar, Sezin Akca; Pinarci, Eylem Yaman; Karabay, Gulten; Akman, Ahmet; Oto, Sibel; Yilmaz, Gursel

2014-01-01

To report the ocular findings of patients with Alport syndrome and the results of clear lens extraction in this patient group. Twenty-three eyes of 15 patients with a diagnosis of Alport syndrome were included in this study. Clear corneal phacoemulsification and intraocular foldable lens implantation was performed in eyes with indeterminate refractive errors and/or poor visual acuity and anterior capsule samples were analyzed with electron microscopy. All patients had a history of hereditary nephritis and/or deafness as systemic involvement. Ophthalmologic examination revealed anterior lenticonus with high myopia and/or irregular astigmatism in all patients. The mean best-corrected visual acuity (BCVA) was 0.67 ± 0.17 logMAR (range 1.0-0.4) preoperatively and 0.17 ± 0.08 logMAR (range 0.3-0.0) postoperatively. Postoperative refractive lenticular astigmatism dramatically decreased and no ocular complications arose during the follow-up period. Transmission electron microscopic analysis of the lens capsules supported the diagnosis of Alport syndrome. Clear lens phacoemulsification and foldable intraocular lens implantation is a safe and effective therapeutic choice for the management of uncorrectable refractive errors and low visual acuity due to anterior lenticonus in patients with Alport syndrome.

The microscopic protein structure of the lens with a theory for cataract formation as determined by Raman spectroscopy of intact bovine lenses.

PubMed

Schachar, R A; Solin, S A

1975-05-01

Intact bovine lenses have been studied using the polarized Raman spectroscopic technique. A brief theoretical and experimental review of Raman spectroscopy is presented. From the dependence of the Raman depolarization ratio on the propagation direction of the incident radiation we have determined that the uniaxial qualities of the lens result from microscopic anisotropy and have established the quantitative positional correlation of specific chemical bonds with respect to the lens optic axis. In particular, the hydrogen bonded linear CONH groups of the antiparallel beta-pleated sheet are preferentially oriented in directions orthogonal to the lens optic axis. The Raman spectra of intact lenses do not exhibit bands at positions characteristic of either the alpha-helix or the random coil protein structure. The antiparallel beta-pleated sheet protein microstructure and the lens fiber cross-sectional macrostructure exhibit a remarkable similarity. This similarity may be causal and is consistent with the protein concentration of the lens, the birefringent properties observed by both Lenhard and Brewster, the CONH bond angle distribution with respect to the optic axis, and the lens anatomy. It is suggested that cortical cataracts are caused by fluctuations in protein orientational order.

Critical dimensional linewidth calibration using UV microscope and laser interferometry

NASA Astrophysics Data System (ADS)

Li, Qi; Gao, Si-tian; Li, Wei; Lu, Ming-zhen; Zhang, Ming-kai

2013-10-01

In order to calibrate the critical dimensional (CD) uncertainty of lithography masks in semiconductor manufacturing, NIM is building a two dimensional metrological UV microscope which has traceable measurement ability for nanometer linewidths and pitches. The microscope mainly consists of UV light receiving components, piezoelectric ceramics (PZT) driven stage and interferometer calibration framework. In UV light receiving components they include all optical elements on optical path. The UV light originates from Köhler high aperture transmit/reflect illumination sources; then goes through objective lens to UV splitting optical elements; after that, one part of light attains UV camera for large range calibration, the other part of light passes through a three dimensional adjusted pinhole and is collected by PMT for nanoscale scanning. In PZT driven stage, PZT stick actuators with closed loop control are equipped to push/pull a flexural hinge based platform. The platform has a novel designed compound flexural hinges which nest separate X, Y direction moving mechanisms within one layer but avoiding from mutual cross talk, besides this, the hinges also contain leverage structures to amplify moving distance. With these designs, the platform can attain 100 μm displacement ranges as well as 1 nm resolution. In interferometer framework a heterodyne multi-pass interferometer is mounted on the platform, which measures X-Y plane movement and Z axis rotation, through reference mirror mounted on objective lens tube and Zerodur mirror mounted on PZT platform, the displacement is traced back to laser wavelength. When development is finished, the apparatus can offer the capability to calibrate one dimensional linewidths and two dimensional pitches ranging from 200nm to 50μm with expanded uncertainty below 20nm.

A study on high NA and evanescent imaging with polarized illumination

NASA Astrophysics Data System (ADS)

Yang, Seung-Hune

Simulation techniques are developed for high NA polarized microscopy with Babinet's principle, partial coherence and vector diffraction for non-periodic geometries. A mathematical model for the Babinet approach is developed and interpreted. Simulation results of the Babinet's principle approach are compared with those of Rigorous Coupled Wave Theory (RCWT) for periodic structures to investigate the accuracy of this approach and its limitations. A microscope system using a special solid immersion lens (SIL) is introduced to image Blu-Ray (BD) optical disc samples without removing the protective cover layer. Aberration caused by the cover layer is minimized with a truncated SIL. Sub-surface imaging simulation is achieved by RCWT, partial coherence, vector diffraction and Babinet's Principle. Simulated results are compared with experimental images and atomic force microscopy (AFM) measurement. A technique for obtaining native and induced using a significant amount of evanescent energy is described for a solid immersion lens (SIL) microscope. Characteristics of native and induced polarization images for different object structures and materials are studied in detail. Experiments are conducted with a NA = 1.48 at lambda = 550nm microscope. Near-field images are simulated and analyzed with an RCWT approach. Contrast curve versus object spatial frequency calculations are compared with experimental measurements. Dependencies of contrast versus source polarization angles and air gap for native and induced polarization image profiles are evaluated. By using the relationship between induced polarization and topographical structure, an induced polarization image of an alternating phase shift mask (PSM) is converted into a topographical image, which shows very good agreement with AFM measurement. Images of other material structures include a dielectric grating, chrome-on-glass grating, silicon CPU structure, BD-R and BD-ROM.

Color calibration and fusion of lens-free and mobile-phone microscopy images for high-resolution and accurate color reproduction

NASA Astrophysics Data System (ADS)

Zhang, Yibo; Wu, Yichen; Zhang, Yun; Ozcan, Aydogan

2016-06-01

Lens-free holographic microscopy can achieve wide-field imaging in a cost-effective and field-portable setup, making it a promising technique for point-of-care and telepathology applications. However, due to relatively narrow-band sources used in holographic microscopy, conventional colorization methods that use images reconstructed at discrete wavelengths, corresponding to e.g., red (R), green (G) and blue (B) channels, are subject to color artifacts. Furthermore, these existing RGB colorization methods do not match the chromatic perception of human vision. Here we present a high-color-fidelity and high-resolution imaging method, termed “digital color fusion microscopy” (DCFM), which fuses a holographic image acquired at a single wavelength with a color-calibrated image taken by a low-magnification lens-based microscope using a wavelet transform-based colorization method. We demonstrate accurate color reproduction of DCFM by imaging stained tissue sections. In particular we show that a lens-free holographic microscope in combination with a cost-effective mobile-phone-based microscope can generate color images of specimens, performing very close to a high numerical-aperture (NA) benchtop microscope that is corrected for color distortions and chromatic aberrations, also matching the chromatic response of human vision. This method can be useful for wide-field imaging needs in telepathology applications and in resource-limited settings, where whole-slide scanning microscopy systems are not available.

Color calibration and fusion of lens-free and mobile-phone microscopy images for high-resolution and accurate color reproduction

PubMed Central

Zhang, Yibo; Wu, Yichen; Zhang, Yun; Ozcan, Aydogan

2016-01-01

Lens-free holographic microscopy can achieve wide-field imaging in a cost-effective and field-portable setup, making it a promising technique for point-of-care and telepathology applications. However, due to relatively narrow-band sources used in holographic microscopy, conventional colorization methods that use images reconstructed at discrete wavelengths, corresponding to e.g., red (R), green (G) and blue (B) channels, are subject to color artifacts. Furthermore, these existing RGB colorization methods do not match the chromatic perception of human vision. Here we present a high-color-fidelity and high-resolution imaging method, termed “digital color fusion microscopy” (DCFM), which fuses a holographic image acquired at a single wavelength with a color-calibrated image taken by a low-magnification lens-based microscope using a wavelet transform-based colorization method. We demonstrate accurate color reproduction of DCFM by imaging stained tissue sections. In particular we show that a lens-free holographic microscope in combination with a cost-effective mobile-phone-based microscope can generate color images of specimens, performing very close to a high numerical-aperture (NA) benchtop microscope that is corrected for color distortions and chromatic aberrations, also matching the chromatic response of human vision. This method can be useful for wide-field imaging needs in telepathology applications and in resource-limited settings, where whole-slide scanning microscopy systems are not available. PMID:27283459

Color calibration and fusion of lens-free and mobile-phone microscopy images for high-resolution and accurate color reproduction.

PubMed

Zhang, Yibo; Wu, Yichen; Zhang, Yun; Ozcan, Aydogan

2016-06-10

Lens-free holographic microscopy can achieve wide-field imaging in a cost-effective and field-portable setup, making it a promising technique for point-of-care and telepathology applications. However, due to relatively narrow-band sources used in holographic microscopy, conventional colorization methods that use images reconstructed at discrete wavelengths, corresponding to e.g., red (R), green (G) and blue (B) channels, are subject to color artifacts. Furthermore, these existing RGB colorization methods do not match the chromatic perception of human vision. Here we present a high-color-fidelity and high-resolution imaging method, termed "digital color fusion microscopy" (DCFM), which fuses a holographic image acquired at a single wavelength with a color-calibrated image taken by a low-magnification lens-based microscope using a wavelet transform-based colorization method. We demonstrate accurate color reproduction of DCFM by imaging stained tissue sections. In particular we show that a lens-free holographic microscope in combination with a cost-effective mobile-phone-based microscope can generate color images of specimens, performing very close to a high numerical-aperture (NA) benchtop microscope that is corrected for color distortions and chromatic aberrations, also matching the chromatic response of human vision. This method can be useful for wide-field imaging needs in telepathology applications and in resource-limited settings, where whole-slide scanning microscopy systems are not available.

An orientation-independent DIC microscope allows high resolution imaging of epithelial cell migration and wound healing in a Cnidarian model

PubMed Central

Malamy, Jocelyn; Shribak, Michael

2017-01-01

Epithelial cell dynamics can be difficult to study in intact animals or tissues. Here we use the medusa form of the hydrozoan Clytia hemisphaerica, which is covered with a monolayer of epithelial cells, to test the efficacy of an orientation-independent differential interference contrast (OI-DIC) microscope for in vivo imaging of wound healing. OI-DIC provides an unprecedented resolution phase image of epithelial cells closing a wound in a live, non-transgenic animal model. In particular, the OI-DIC microscope equipped with a 40×/0.75NA objective lens and using the illumination light with wavelength 546 nm demonstrated a resolution of 460 nm. The repair of individual cells, the adhesion of cells to close a gap, and the concomitant contraction of these cells during closure is clearly visualized. PMID:29345317

Construction of a femtosecond laser microsurgery system.

PubMed

Steinmeyer, Joseph D; Gilleland, Cody L; Pardo-Martin, Carlos; Angel, Matthew; Rohde, Christopher B; Scott, Mark A; Yanik, Mehmet Fatih

2010-03-01

Femtosecond laser microsurgery is a powerful method for studying cellular function, neural circuits, neuronal injury and neuronal regeneration because of its capability to selectively ablate sub-micron targets in vitro and in vivo with minimal damage to the surrounding tissue. Here, we present a step-by-step protocol for constructing a femtosecond laser microsurgery setup for use with a widely available compound fluorescence microscope. The protocol begins with the assembly and alignment of beam-conditioning optics at the output of a femtosecond laser. Then a dichroic mount is assembled and installed to direct the laser beam into the objective lens of a standard inverted microscope. Finally, the laser is focused on the image plane of the microscope to allow simultaneous surgery and fluorescence imaging. We illustrate the use of this setup by presenting axotomy in Caenorhabditis elegans as an example. This protocol can be completed in 2 d.

A simple and low-cost structured illumination microscopy using a pico-projector

NASA Astrophysics Data System (ADS)

Özgürün, Baturay

2018-02-01

Here, development of a low-cost structured illumination microscopy (SIM) based on a pico-projector is presented. The pico-projector consists of independent red, green and blue LEDs that remove need for an external illumination source. Moreover, display element of the pico-projector serves as a pattern generating spatial light modulator. A simple lens group is employed to couple light from the projector to an epi-illumination port of a commercial microscope system. 2D sub SIM images are acquired and synthesized to surpass the diffraction limit using 40x (0.75 NA) objective. Resolution of the reconstructed SIM images is verified with a dye-and-object object and a fixed cell sample.

Generic distortion model for metrology under optical microscopes

NASA Astrophysics Data System (ADS)

Liu, Xingjian; Li, Zhongwei; Zhong, Kai; Chao, YuhJin; Miraldo, Pedro; Shi, Yusheng

2018-04-01

For metrology under optical microscopes, lens distortion is the dominant source of error. Previous distortion models and correction methods mostly rely on the assumption that parametric distortion models require a priori knowledge of the microscopes' lens systems. However, because of the numerous optical elements in a microscope, distortions can be hardly represented by a simple parametric model. In this paper, a generic distortion model considering both symmetric and asymmetric distortions is developed. Such a model is obtained by using radial basis functions (RBFs) to interpolate the radius and distortion values of symmetric distortions (image coordinates and distortion rays for asymmetric distortions). An accurate and easy to implement distortion correction method is presented. With the proposed approach, quantitative measurement with better accuracy can be achieved, such as in Digital Image Correlation for deformation measurement when used with an optical microscope. The proposed technique is verified by both synthetic and real data experiments.

Highly charged ion based time of flight emission microscope

DOEpatents

Barnes, Alan V.; Schenkel, Thomas; Hamza, Alex V.; Schneider, Dieter H.; Doyle, Barney

2001-01-01

A highly charged ion based time-of-flight emission microscope has been designed, which improves the surface sensitivity of static SIMS measurements because of the higher ionization probability of highly charged ions. Slow, highly charged ions are produced in an electron beam ion trap and are directed to the sample surface. The sputtered secondary ions and electrons pass through a specially designed objective lens to a microchannel plate detector. This new instrument permits high surface sensitivity (10.sup.10 atoms/cm.sup.2), high spatial resolution (100 nm), and chemical structural information due to the high molecular ion yields. The high secondary ion yield permits coincidence counting, which can be used to enhance determination of chemical and topological structure and to correlate specific molecular species.

Fine Metal Mask 3-Dimensional Measurement by using Scanning Digital Holographic Microscope

NASA Astrophysics Data System (ADS)

Shin, Sanghoon; Yu, Younghun

2018-04-01

For three-dimensional microscopy, fast and high axial resolution are very important. Extending the depth of field for digital holographic is necessary for three-dimensional measurements of thick samples. We propose an optical sectioning method for optical scanning digital holography that is performed in the frequency domain by spatial filtering of a reconstructed amplitude image. We established a scanning dual-wavelength off-axis digital holographic microscope to measure samples that exhibit a large amount of coherent noise and a thickness larger than the depth of focus of the objective lens. As a demonstration, we performed a three-dimensional measurement of a fine metal mask with a reconstructed sectional phase image and filtering with a reconstructed amplitude image.

Temporal focusing-based multiphoton excitation microscopy via digital micromirror device.

PubMed

Yih, Jenq-Nan; Hu, Yvonne Yuling; Sie, Yong Da; Cheng, Li-Chung; Lien, Chi-Hsiang; Chen, Shean-Jen

2014-06-01

This Letter presents an enhanced temporal focusing-based multiphoton excitation (MPE) microscope in which the conventional diffraction grating is replaced by a digital micromirror device (DMD). Experimental results from imaging a thin fluorescence film show that the 4.0 μm axial resolution of the microscope is comparable with that of a setup incorporating a 600  lines/mm grating; hence, the optical sectioning ability of the proposed setup is demonstrated. Similar to a grating, the DMD diffracts illuminating light frequencies for temporal focusing; additionally, it generates arbitrary patterns. Since the DMD is placed on the image-conjugate plane of the objective lens' focal plane, the MPE pattern can be projected on the focal plane precisely.

Singlet gradient index lens for deep in vivo multiphoton microscopy

NASA Astrophysics Data System (ADS)

Murray, Teresa A.; Levene, Michael J.

2012-02-01

Micro-optical probes, including gradient index (GRIN) lenses and microprisms, have expanded the range of in vivo multiphoton microscopy to reach previously inaccessible deep brain structures such as deep cortical layers and the underlying hippocampus in mice. Yet imaging with GRIN lenses has been fundamentally limited by large amounts of spherical aberration and the need to construct compound lenses that limit the field-of-view. Here, we demonstrate the use of 0.5-mm-diameter, 1.7-mm-long GRIN lens singlets with 0.6 numerical aperture in conjunction with a cover glass and a conventional microscope objective correction collar to balance spherical aberrations. The resulting system achieves a lateral resolution of 618 nm and an axial resolution of 5.5 μm, compared to lateral and axial resolutions of ~1 μm and ~15 μm, respectively, for compound GRIN lenses of similar diameter. Furthermore, the GRIN lens singlets display fields-of-view in excess of 150 μm, compared with a few tens of microns for compound GRIN lenses. The GRIN lens/cover glass combination presented here is easy to assemble and inexpensive enough for use as a disposable device, enabling ready adoption by the neuroscience community.

Quantifying distortions in two-photon remote focussing microscope images using a volumetric calibration specimen

PubMed Central

Corbett, Alexander D.; Burton, Rebecca A. B.; Bub, Gil; Salter, Patrick S.; Tuohy, Simon; Booth, Martin J.; Wilson, Tony

2014-01-01

Remote focussing microscopy allows sharp, in-focus images to be acquired at high speed from outside of the focal plane of an objective lens without any agitation of the specimen. However, without careful optical alignment, the advantages of remote focussing microscopy could be compromised by the introduction of depth-dependent scaling artifacts. To achieve an ideal alignment in a point-scanning remote focussing microscope, the lateral (XY) scan mirror pair must be imaged onto the back focal plane of both the reference and imaging objectives, in a telecentric arrangement. However, for many commercial objective lenses, it can be difficult to accurately locate the position of the back focal plane. This paper investigates the impact of this limitation on the fidelity of three-dimensional data sets of living cardiac tissue, specifically the introduction of distortions. These distortions limit the accuracy of sarcomere measurements taken directly from raw volumetric data. The origin of the distortion is first identified through simulation of a remote focussing microscope. Using a novel three-dimensional calibration specimen it was then possible to quantify experimentally the size of the distortion as a function of objective misalignment. Finally, by first approximating and then compensating the distortion in imaging data from whole heart rodent studies, the variance of sarcomere length (SL) measurements was reduced by almost 50%. PMID:25339910

Dispersion-compensated fresnel lens

DOEpatents

Johnson, Kenneth C.

1992-01-01

A transmission grating is used to reduce chromatic aberration in a Fresnel lens, wherein the lens chromatic dispersion is offset and substantially canceled by the grating's diffraction-induced dispersion. The grating comprises a Fresnel-type pattern of microscopic facets molded directly into the lens surface. The facets would typically have a profile height of around 4.multidot.10.sup.-5 inch and a profile width of at least 10.sup.-3 inch. In its primary intended application, the invention would function to improve the optical performance of a Fresnel lens used to concentrate direct sunlight.

Dispersion-compensated Fresnel lens

DOEpatents

Johnson, K.C.

1992-11-03

A transmission grating is used to reduce chromatic aberration in a Fresnel lens, wherein the lens chromatic dispersion is offset and substantially canceled by the grating's diffraction-induced dispersion. The grating comprises a Fresnel-type pattern of microscopic facets molded directly into the lens surface. The facets would typically have a profile height of around 4[times]10[sup [minus]5] inch and a profile width of at least 10[sup [minus]3] inch. In its primary intended application, the invention would function to improve the optical performance of a Fresnel lens used to concentrate direct sunlight. 10 figs.

An Introduction to Photomicrography.

ERIC Educational Resources Information Center

Judson, Peter

1979-01-01

Described are various methods for producing black and white photographs of microscope slides using single lens reflex, fixed lens, and plate cameras. Procedures for illumination, film processing, mounting, and projection are also discussed. A table of comparative film speeds is included. (CS)

Periscope for noninvasive two-photon imaging of murine retina in vivo

PubMed Central

Stremplewski, Patrycjusz; Komar, Katarzyna; Palczewski, Krzysztof; Wojtkowski, Maciej; Palczewska, Grazyna

2015-01-01

Two-photon microscopy allows visualization of subcellular structures in the living animal retina. In previously reported experiments it was necessary to apply a contact lens to each subject. Extending this technology to larger animals would require fitting a custom contact lens to each animal and cumbersome placement of the living animal head on microscope stage. Here we demonstrate a new device, periscope, for coupling light energy into mouse eye and capturing emitted fluorescence. Using this periscope we obtained images of the RPE and their subcellular organelles, retinosomes, with larger field of view than previously reported. This periscope provides an interface with a commercial microscope, does not require contact lens and its design could be modified to image retina in larger animals. PMID:26417507

A compact Acousto-Optic Lens for 2D and 3D femtosecond based 2-photon microscopy.

PubMed

Kirkby, Paul A; Srinivas Nadella, K M Naga; Silver, R Angus

2010-06-21

We describe a high speed 3D Acousto-Optic Lens Microscope (AOLM) for femtosecond 2-photon imaging. By optimizing the design of the 4 AO Deflectors (AODs) and by deriving new control algorithms, we have developed a compact spherical AOL with a low temporal dispersion that enables 2-photon imaging at 10-fold lower power than previously reported. We show that the AOLM can perform high speed 2D raster-scan imaging (>150 Hz) without scan rate dependent astigmatism. It can deflect and focus a laser beam in a 3D random access sequence at 30 kHz and has an extended focusing range (>137 mum; 40X 0.8NA objective). These features are likely to make the AOLM a useful tool for studying fast physiological processes distributed in 3D space.

Three-dimensional motion-picture imaging of dynamic object by parallel-phase-shifting digital holographic microscopy using an inverted magnification optical system

NASA Astrophysics Data System (ADS)

Fukuda, Takahito; Shinomura, Masato; Xia, Peng; Awatsuji, Yasuhiro; Nishio, Kenzo; Matoba, Osamu

2017-04-01

We constructed a parallel-phase-shifting digital holographic microscopy (PPSDHM) system using an inverted magnification optical system, and succeeded in three-dimensional (3D) motion-picture imaging for 3D displacement of a microscopic object. In the PPSDHM system, the inverted and afocal magnification optical system consisted of a microscope objective (16.56 mm focal length and 0.25 numerical aperture) and a convex lens (300 mm focal length and 82 mm aperture diameter). A polarization-imaging camera was used to record multiple phase-shifted holograms with a single-shot exposure. We recorded an alum crystal, sinking down in aqueous solution of alum, by the constructed PPSDHM system at 60 frames/s for about 20 s and reconstructed high-quality 3D motion-picture image of the crystal. Then, we calculated amounts of displacement of the crystal from the amounts in the focus plane and the magnifications of the magnification optical system, and obtained the 3D trajectory of the crystal by that amounts.

Assessment of a liquid lens enabled in vivo optical coherence microscope.

PubMed

Murali, Supraja; Meemon, Panomsak; Lee, Kye-Sung; Kuhn, William P; Thompson, Kevin P; Rolland, Jannick P

2010-06-01

The optical aberrations induced by imaging through skin can be predicted using formulas for Seidel aberrations of a plane-parallel plate. Knowledge of these aberrations helps to guide the choice of numerical aperture (NA) of the optics we can use in an implementation of Gabor domain optical coherence microscopy (GD-OCM), where the focus is the only aberration adjustment made through depth. On this basis, a custom-designed, liquid-lens enabled dynamic focusing optical coherence microscope operating at 0.2 NA is analyzed and validated experimentally. As part of the analysis, we show that the full width at half-maximum metric, as a characteristic descriptor for the point spread function, while commonly used, is not a useful metric for quantifying resolution in non-diffraction-limited systems. Modulation transfer function (MTF) measurements quantify that the liquid lens performance is as predicted by design, even when accounting for the effect of gravity. MTF measurements in a skinlike scattering medium also quantify the performance of the microscope in its potential applications. To guide the fusion of images across the various focus positions of the microscope, as required in GD-OCM, we present depth of focus measurements that can be used to determine the effective number of focusing zones required for a given goal resolution. Subcellular resolution in an onion sample, and high-definition in vivo imaging in human skin are demonstrated with the custom-designed and built microscope.

Dynamic-focusing microscope objective for optical coherence tomography

NASA Astrophysics Data System (ADS)

Murali, Supraja; Rolland, Jannick

2007-01-01

Optical Coherence Tomography (OCT) is a novel optical imaging technique that has assumed significant importance in bio-medical imaging in the last two decades because it is non-invasive and provides accurate, high resolution images of three dimensional cross-sections of body tissue, exceeding the capabilities of the current predominant imaging technique - ultrasound. In this paper, the application of high resolution OCT, known as optical coherence microscopy (OCM) is investigated for in vivo detection of abnormal skin pathology for the early diagnosis of cancer. A main challenge in OCM is maintaining invariant resolution throughout the sample. The technology presented is based on a dynamic focusing microscope imaging probe conceived for skin imaging and the detection of abnormalities in the epithelium. A novel method for dynamic focusing in the biological sample is presented using variable-focus lens technology to obtain three dimensional images with invariant resolution throughout the cross-section and depth of the sample is presented and discussed. A low coherence broadband source centered at near IR wavelengths is used to illuminate the sample. The design, analysis and predicted performance of the dynamic focusing microscope objective designed for dynamic three dimensional imaging at 5μm resolution for the chosen broadband spectrum is presented.

Atomic force microscopy and scanning electron microscopy analysis of daily disposable limbal ring contact lenses.

PubMed

Lorenz, Kathrine Osborn; Kakkassery, Joseph; Boree, Danielle; Pinto, David

2014-09-01

Limbal ring (also known as 'circle') contact lenses are becoming increasingly popular, especially in Asian markets because of their eye-enhancing effects. The pigment particles that give the eye-enhancing effects of these lenses can be found on the front or back surface of the contact lens or 'enclosed' within the lens matrix. The purpose of this research was to evaluate the pigment location and surface roughness of seven types of 'circle' contact lenses. Scanning electron microscopic (SEM) analysis was performed using a variable pressure Hitachi S3400N instrument to discern the placement of lens pigments. Atomic force microscopy (Dimension Icon AFM from Bruker Nano) was used to determine the surface roughness of the pigmented regions of the contact lenses. Atomic force microscopic analysis was performed in fluid phase under contact mode using a Sharp Nitride Lever probe (SNL-10) with a spring constant of 0.06 N/m. Root mean square (RMS) roughness values were analysed using a generalised linear mixed model with a log-normal distribution. Least square means and their corresponding 95% confidence intervals were estimated for each brand, location and pigment combination. SEM cross-sectional images at 500× and 2,000× magnification showed pigment on the surface of six of the seven lens types tested. The mean depth of pigment for 1-DAY ACUVUE DEFINE (1DAD) lenses was 8.1 μm below the surface of the lens, while the remaining lens types tested had pigment particles on the front or back surface. Results of the atomic force microscopic analysis indicated that 1DAD lenses had significantly lower root mean square roughness values in the pigmented area of the lens than the other lens types tested. SEM and AFM analysis revealed pigment on the surface of the lens for all types tested with the exception of 1DAD. Further research is required to determine if the difference in pigment location influences on-eye performance. © 2014 The Authors. Clinical and Experimental Optometry © 2014 Optometrists Association Australia.

Atomic force microscopy and scanning electron microscopy analysis of daily disposable limbal ring contact lenses

PubMed Central

Lorenz, Kathrine Osborn; Kakkassery, Joseph; Boree, Danielle; Pinto, David

2014-01-01

Background Limbal ring (also known as ‘circle’) contact lenses are becoming increasingly popular, especially in Asian markets because of their eye-enhancing effects. The pigment particles that give the eye-enhancing effects of these lenses can be found on the front or back surface of the contact lens or ‘enclosed’ within the lens matrix. The purpose of this research was to evaluate the pigment location and surface roughness of seven types of ‘circle’ contact lenses. Methods Scanning electron microscopic (SEM) analysis was performed using a variable pressure Hitachi S3400N instrument to discern the placement of lens pigments. Atomic force microscopy (Dimension Icon AFM from Bruker Nano) was used to determine the surface roughness of the pigmented regions of the contact lenses. Atomic force microscopic analysis was performed in fluid phase under contact mode using a Sharp Nitride Lever probe (SNL-10) with a spring constant of 0.06 N/m. Root mean square (RMS) roughness values were analysed using a generalised linear mixed model with a log-normal distribution. Least square means and their corresponding 95% confidence intervals were estimated for each brand, location and pigment combination. Results SEM cross-sectional images at 500× and 2,000× magnification showed pigment on the surface of six of the seven lens types tested. The mean depth of pigment for 1-DAY ACUVUE DEFINE (1DAD) lenses was 8.1 μm below the surface of the lens, while the remaining lens types tested had pigment particles on the front or back surface. Results of the atomic force microscopic analysis indicated that 1DAD lenses had significantly lower root mean square roughness values in the pigmented area of the lens than the other lens types tested. Conclusions SEM and AFM analysis revealed pigment on the surface of the lens for all types tested with the exception of 1DAD. Further research is required to determine if the difference in pigment location influences on-eye performance. PMID:24689948

Compact multi-band fluorescent microscope with an electrically tunable lens for autofocusing

PubMed Central

Wang, Zhaojun; Lei, Ming; Yao, Baoli; Cai, Yanan; Liang, Yansheng; Yang, Yanlong; Yang, Xibin; Li, Hui; Xiong, Daxi

2015-01-01

Autofocusing is a routine technique in redressing focus drift that occurs in time-lapse microscopic image acquisition. To date, most automatic microscopes are designed on the distance detection scheme to fulfill the autofocusing operation, which may suffer from the low contrast of the reflected signal due to the refractive index mismatch at the water/glass interface. To achieve high autofocusing speed with minimal motion artifacts, we developed a compact multi-band fluorescent microscope with an electrically tunable lens (ETL) device for autofocusing. A modified searching algorithm based on equidistant scanning and curve fitting is proposed, which no longer requires a single-peak focus curve and then efficiently restrains the impact of external disturbance. This technique enables us to achieve an autofocusing time of down to 170 ms and the reproductivity of over 97%. The imaging head of the microscope has dimensions of 12 cm × 12 cm × 6 cm. This portable instrument can easily fit inside standard incubators for real-time imaging of living specimens. PMID:26601001

Hard X-Ray Scanning Microscope with Multilayer Laue Lens Nanofocusing Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nazaretski, Evgeny

Evgeny Nazaretski, a physicist at Brookhaven Lab’s National Synchrotron Light Source II, spearheaded the development of a one-of-a-kind x-ray microscope with novel nanofocusing optics called multilayer Laue lenses.

Increasing Student Understanding of Microscope Optics by Building and Testing the Limits of Simple, Hand-Made Model Microscopes†

PubMed Central

Drace, Kevin; Couch, Brett; Keeling, Patrick J.

2012-01-01

The ability to effectively use a microscope to observe microorganisms is a crucial skill required for many disciplines within biology, especially general microbiology and cell biology. A basic understanding of the optical properties of light microscopes is required for students to use microscopes effectively, but this subject can also be a challenge to make personally interesting to students. To explore basic optical principles of magnification and resolving power in a more engaging and hands-on fashion, students constructed handmade lenses and microscopes based on Antony van Leeuwenhoek’s design using simple materials—paper, staples, glass, and adhesive putty. Students determined the power of their lenses using a green laser pointer to magnify a copper grid of known size, which also allowed students to examine variables affecting the power and resolution of a lens such as diameter, working distance, and wavelength of light. To assess the effectiveness of the laboratory’s learning objectives, four sections of a general microbiology course were given a brief pre-activity assessment quiz to determine their background knowledge on the subject. One week after the laboratory activity, students were given the same quiz (unannounced) under similar conditions. Students showed significant gains in their understanding of microscope optics. PMID:23653781

Direct laser writing for micro-optical devices using a negative photoresist.

PubMed

Tsutsumi, Naoto; Hirota, Junichi; Kinashi, Kenji; Sakai, Wataru

2017-12-11

Direct laser writing (DLW) via two-photon absorption (TPA) has attracted much attention as a new microfabrication technique because it can be applied to fabricate complex, three-dimensional (3D) microstructures. In this study, 3D microstructures and micro-optical devices of micro-lens array on the micrometer scale are fabricated using the negative photoresist SU-8 through TPA with a femtosecond laser pulse under a microscope. The effects of the irradiation conditions on linewidths, such as laser power, writing speed, and writing cycles (a number of times a line is overwritten), are investigated before the fabrication of the 3D microstructures. Various microstructures such as woodpiles, hemisphere and microstructures, 3D micro-lens and micro-lens array for micro-optical devices are fabricated. The shape of the micro-lens is evaluated using the shape analysis mode of a laser microscope to calculate the working distance of the fabricated micro-lenses. The calculated working distance corresponds well to the experimentally measured value. The focusing performance of the fabricated micro-lens is confirmed by the TPA fluorescence of an isopropyl thioxanthone (ITX) ethanol solution excited by a Ti:sapphire femtosecond laser at 800 nm. Micro-lens array (assembled 9 micro-lenses) are fabricated. Nine independent woodpile structures are simultaneously manufactured by DLW via TPA to confirm the multi-focusing ability using the fabricated micro-lens array.

Development of SEM/STEM-WDX for highly sensitive detection of light elements

NASA Astrophysics Data System (ADS)

Anan, Y.; Koguchi, M.; Kimura, T.; Sekiguchi, T.

2018-02-01

In this study, to detect the light element lithium (Li) and to detect low dosed Boron (B) in the local area at nm order, we developed an analytical electron microscope equipped with an improved serial (S)-type WDX (wavelength dispersive X-ray spectroscopy) system. In detail, to detect Li, we developed a high-conductivity multi-capillary X-ray (MCX) lens, and a diffractor with a lattice spacing (d) of 15 nm, and with a spacing variation (δ d) of 0.8 nm. Moreover, to detect low dosed light element B, we designed a high-conductivity MCX lens based on the soft X-ray reflectivity in the capillary and calculation. We developed a large-solid-angle MCX lens whose conductivity of the characteristic X-rays of B became 20 times higher than that of an MCX lens with a 30-mm focal length. Our developed analytical electron microscope was applied to a LiAl specimen and a low B-doped Si substrate specimen, and the performance of this analytical electron microscope was evaluated. As a results, this analytical electron microscope could detect the characteristic X-rays of Li with a minimum mass fraction (MMF) of 8.4 atomic % (at. %). The energy resolution was 1 eV at 55 eV. From the results of measuring the line profile of B for the unpatterned B-implantation area on a B-doped Si substrate specimen, the measured line profile data were in good agreement with secondary ion mass spectrometry data up to a depth of 100 nm with a B concentration of 0.05 at. %.

Effect of the Femtosecond Laser on an Intracorneal Inlay for Surgical Compensation of Presbyopia during Cataract Surgery: Scanning Electron Microscope Imaging.

PubMed

Ibarz, Marta; Rodríguez-Prats, Jose Luis; Hernández-Verdejo, Jose Luis; Tañá, Pedro

2017-02-01

To investigate the effect of the femtosecond laser-assisted cataract surgery (FLACS) on porcine eyes implanted with a Kamra corneal inlay and to describe how the inlay may change the effect of the femtosecond laser on the lens. FLACS was performed on six porcine eyes and a Kamra corneal inlay had been implanted, exploring the lens under the surgical microscope. Another Kamra corneal inlay was attached to the upper part of the transparent hemisphere used for calibration of the femtosecond laser. Capsulorhexis, arcuate incisions, and phacofragmentation were carried out. The Kamra corneal inlay was compared with a nontreated one using a scanning electron microscope (SEM), and the hemisphere was analyzed with a surgical microscope. Capsulorhexis and phacofragmentation were completed in all the porcine eyes, although accuracy to determine the exact effect on the lens was not possible to achieve. The effect of the femtosecond laser on the PMMA hemisphere through the Kamra corneal inlay showed the capsulorhexis was placed outside the outer margin of the inlay and a sharply sculpted fragmentation pattern with a three-dimensional (donut-shaped) annulus untreated beneath it. SEM images of the nontreated and the treated inlays were comparable. No ultrastructural changes were found in the treated Kamra corneal inlay. FLACS can be performed with a Kamra corneal inlay for surgical compensation of presbyopia without the risk of damaging the inlay. The Kamra corneal inlay acts as a screen that avoids the laser to reach the areas beneath its shadow, but not the exposed areas of the lens.

Fabrication of miniature elastomer lenses with programmable liquid mold for smartphone microscopy: curing polydimethylsiloxane with in situ curvature control

NASA Astrophysics Data System (ADS)

Karunakaran, Bhuvaneshwari; Tharion, Joseph; Dhawangale, Arvind Ramrao; Paul, Debjani; Mukherji, Soumyo

2018-02-01

Miniature lenses can transform commercial imaging systems, e.g., smartphones and webcams, into powerful, low-cost, handheld microscopes. To date, the reproducible fabrication of polymer lenses is still a challenge as they require controlled dispensing of viscous liquid. This paper reports a reproducible lens fabrication technique using liquid mold with programmable curvature and off-the-shelf materials. The lens curvature is controlled during fabrication by tuning the curvature of an interface of two immiscible liquids [polydimethylsiloxane (PDMS) and glycerol]. The curvature control is implemented using a visual feedback system, which includes a software-based guiding system to produce lenses of desired curvature. The technique allows PDMS lens fabrication of a wide range of sizes and focal lengths, within 20 min. The fabrication of two lens diameters: 1 and 5 mm with focal lengths ranging between 1.2 and 11 mm are demonstrated. The lens surface and bulk quality check performed using X-ray microtomography and atomic force microscopy reveal that the lenses are suitable for optical imaging. Furthermore, a smartphone microscope with ˜1.4-μm resolution is developed using a self-assembly of a single high power fabricated lens and microaperture. The lenses have various potential applications, e.g., optofluidics, diagnostics, forensics, and surveillance.

Development and Optical Testing of the Camera, Hand Lens, and Microscope Probe with Scannable Laser Spectroscopy (CHAMP-SLS)

NASA Technical Reports Server (NTRS)

Mungas, Greg S.; Gursel, Yekta; Sepulveda, Cesar A.; Anderson, Mark; La Baw, Clayton; Johnson, Kenneth R.; Deans, Matthew; Beegle, Luther; Boynton, John

2008-01-01

Conducting high resolution field microscopy with coupled laser spectroscopy that can be used to selectively analyze the surface chemistry of individual pixels in a scene is an enabling capability for next generation robotic and manned spaceflight missions, civil, and military applications. In the laboratory, we use a range of imaging and surface preparation tools that provide us with in-focus images, context imaging for identifying features that we want to investigate at high magnification, and surface-optical coupling that allows us to apply optical spectroscopic analysis techniques for analyzing surface chemistry particularly at high magnifications. The camera, hand lens, and microscope probe with scannable laser spectroscopy (CHAMP-SLS) is an imaging/spectroscopy instrument capable of imaging continuously from infinity down to high resolution microscopy (resolution of approx. 1 micron/pixel in a final camera format), the closer CHAMP-SLS is placed to a feature, the higher the resultant magnification. At hand lens to microscopic magnifications, the imaged scene can be selectively interrogated with point spectroscopic techniques such as Raman spectroscopy, microscopic Laser Induced Breakdown Spectroscopy (micro-LIBS), laser ablation mass-spectrometry, Fluorescence spectroscopy, and/or Reflectance spectroscopy. This paper summarizes the optical design, development, and testing of the CHAMP-SLS optics.

Hard X-Ray Scanning Microscope with Multilayer Laue Lens Nanofocusing Optics

ScienceCinema

Nazaretski, Evgeny

2018-06-13

Evgeny Nazaretski, a physicist at Brookhaven Lab’s National Synchrotron Light Source II, spearheaded the development of a one-of-a-kind x-ray microscope with novel nanofocusing optics called multilayer Laue lenses.

Measuring chromatic aberrations in imaging systems using plasmonic nanoparticles.

PubMed

Gennaro, Sylvain D; Roschuk, Tyler R; Maier, Stefan A; Oulton, Rupert F

2016-04-01

We demonstrate a method to measure chromatic aberrations of microscope objectives with metallic nanoparticles using white light. Extinction spectra are recorded while scanning a single nanoparticle through a lens's focal plane. We show a direct correlation between the focal wavelength and the longitudinal chromatic focal shift through our analysis of the variations between the scanned extinction spectra at each scan position and the peak extinction over the entire scan. The method has been tested on achromat and apochromat objectives using aluminum disks varying in size from 260-520 nm. Our method is straightforward, robust, low cost, and broadband with a sensitivity suitable for assessing longitudinal chromatic aberrations in high-numerical-aperture apochromatic corrected lenses.

A compact acousto-optic lens for 2D and 3D femtosecond based 2-photon microscopy

PubMed Central

Kirkby, Paul A.; Naga Srinivas, N.K.M.; Silver, R. Angus

2010-01-01

We describe a high speed 3D Acousto-Optic Lens Microscope (AOLM) for femtosecond 2-photon imaging. By optimizing the design of the 4 AO Deflectors (AODs) and by deriving new control algorithms, we have developed a compact spherical AOL with a low temporal dispersion that enables 2-photon imaging at 10-fold lower power than previously reported. We show that the AOLM can perform high speed 2D raster-scan imaging (>150 Hz) without scan rate dependent astigmatism. It can deflect and focus a laser beam in a 3D random access sequence at 30 kHz and has an extended focusing range (>137 μm; 40X 0.8NA objective). These features are likely to make the AOLM a useful tool for studying fast physiological processes distributed in 3D space PMID:20588506

Reflectance confocal microscopy of oral epithelial tissue using an electrically tunable lens

NASA Astrophysics Data System (ADS)

Jabbour, Joey M.; Malik, Bilal H.; Cuenca, Rodrigo; Cheng, Shuna; Jo, Javier A.; Cheng, Yi-Shing L.; Wright, John M.; Maitland, Kristen C.

2014-02-01

We present the use of a commercially available electrically tunable lens to achieve axial scanning in a reflectance confocal microscope. Over a 255 μm axial scan range, the lateral and axial resolutions varied from 1-2 μm and 4-14 μm, respectively, dependent on the variable focal length of the tunable lens. Confocal imaging was performed on normal human biopsies from the oral cavity ex vivo. Sub-cellular morphologic features were seen throughout the depth of the epithelium while axially scanning using the focus tunable lens.

Differential phase acoustic microscope for micro-NDE

NASA Technical Reports Server (NTRS)

Waters, David D.; Pusateri, T. L.; Huang, S. R.

1992-01-01

A differential phase scanning acoustic microscope (DP-SAM) was developed, fabricated, and tested in this project. This includes the acoustic lens and transducers, driving and receiving electronics, scanning stage, scanning software, and display software. This DP-SAM can produce mechanically raster-scanned acoustic microscopic images of differential phase, differential amplitude, or amplitude of the time gated returned echoes of the samples. The differential phase and differential amplitude images provide better image contrast over the conventional amplitude images. A specially designed miniature dual beam lens was used to form two foci to obtain the differential phase and amplitude information of the echoes. High image resolution (1 micron) was achieved by applying high frequency (around 1 GHz) acoustic signals to the samples and placing two foci close to each other (1 micron). Tone burst was used in this system to obtain a good estimation of the phase differences between echoes from the two adjacent foci. The system can also be used to extract the V(z) acoustic signature. Since two acoustic beams and four receiving modes are available, there are 12 possible combinations to produce an image or a V(z) scan. This provides a unique feature of this system that none of the existing acoustic microscopic systems can provide for the micro-nondestructive evaluation applications. The entire system, including the lens, electronics, and scanning control software, has made a competitive industrial product for nondestructive material inspection and evaluation and has attracted interest from existing acoustic microscope manufacturers.

Confocal microscopic observation of structural changes in glass-ionomer cements and tooth interfaces.

PubMed

Watson, T F; Pagliari, D; Sidhu, S K; Naasan, M A

1998-03-01

This study aimed to develop techniques to allow dynamic imaging of a cavity before, during and after placement of glass-ionomer restorative materials. Cavities were cut in recently extracted third molars and the teeth longitudinally sectioned. Each hemisected tooth surface was placed in green modelling compound at 90 to the optical axis of the microscope. The cavity surface was imaged using a video rate confocal microscope in conjunction with an internally focusable microscope objective. The sample on the stage was pushed up to the objective lens which 'clamped' the cover glass onto it. Water, glycerine or oil was placed below the coverglass, with oil above. Internal tooth structures were imaged by changing the internal focus of the objective. The restorative material was then placed into the cavity. Video images were stored either onto video tape or digitally, using a frame grabber, computer and mass memory storage. Software controls produced time-lapse recordings of the interface over time. Preliminary experiments have examined the placement and early maturation of conventional glass-ionomer cements and a syringeable resin-modified glass-ionomer cement. Initial contact of the cement matrix and glass particles was visible as the plastic material rolled past the enamel and dentine, before making a bond. Evidence for water movement from the dentine into the cement has also been seen. After curing, the early dimensional changes in the cements due to water flux were apparent using the time-lapse facility. This new technique enables examination of developing tooth/restoration interfaces and the tracking of movement in materials.

Flexible high-voltage supply for experimental electron microscope

NASA Technical Reports Server (NTRS)

Chapman, G. L.; Jung, E. A.; Lewis, R. N.; Van Loon, L. S.; Welter, L. M.

1969-01-01

Scanning microscope uses a field-emission tip for the electron source, an electron gun that simultaneously accelerates and focuses electrons from the source, and one auxiliary lens to produce a final probe size at the specimen on the order of angstroms.

Three dimensional two-photon brain imaging in freely moving mice using a miniature fiber coupled microscope with active axial-scanning.

PubMed

Ozbay, Baris N; Futia, Gregory L; Ma, Ming; Bright, Victor M; Gopinath, Juliet T; Hughes, Ethan G; Restrepo, Diego; Gibson, Emily A

2018-05-25

We present a miniature head mounted two-photon fiber-coupled microscope (2P-FCM) for neuronal imaging with active axial focusing enabled using a miniature electrowetting lens. We show three-dimensional two-photon imaging of neuronal structure and record neuronal activity from GCaMP6s fluorescence from multiple focal planes in a freely-moving mouse. Two-color simultaneous imaging of GFP and tdTomato fluorescence is also demonstrated. Additionally, dynamic control of the axial scanning of the electrowetting lens allows tilting of the focal plane enabling neurons in multiple depths to be imaged in a single plane. Two-photon imaging allows increased penetration depth in tissue yielding a working distance of 450 μm with an additional 180 μm of active axial focusing. The objective NA is 0.45 with a lateral resolution of 1.8 μm, an axial resolution of 10 μm, and a field-of-view of 240 μm diameter. The 2P-FCM has a weight of only ~2.5 g and is capable of repeatable and stable head-attachment. The 2P-FCM with dynamic axial scanning provides a new capability to record from functionally distinct neuronal layers, opening new opportunities in neuroscience research.

An inexpensive programmable illumination microscope with active feedback.

PubMed

Tompkins, Nathan; Fraden, Seth

2016-02-01

We have developed a programmable illumination system capable of tracking and illuminating numerous objects simultaneously using only low-cost and reused optical components. The active feedback control software allows for a closed-loop system that tracks and perturbs objects of interest automatically. Our system uses a static stage where the objects of interest are tracked computationally as they move across the field of view allowing for a large number of simultaneous experiments. An algorithmically determined illumination pattern can be applied anywhere in the field of view with simultaneous imaging and perturbation using different colors of light to enable spatially and temporally structured illumination. Our system consists of a consumer projector, camera, 35-mm camera lens, and a small number of other optical and scaffolding components. The entire apparatus can be assembled for under $4,000.

Phase contrast in high resolution electron microscopy

DOEpatents

Rose, H.H.

1975-09-23

This patent relates to a device for developing a phase contrast signal for a scanning transmission electron microscope. The lens system of the microscope is operated in a condition of defocus so that predictable alternate concentric regions of high and low electron density exist in the cone of illumination. Two phase detectors are placed beneath the object inside the cone of illumination, with the first detector having the form of a zone plate, each of its rings covering alternate regions of either higher or lower electron density. The second detector is so configured that it covers the regions of electron density not covered by the first detector. Each detector measures the number of electrons incident thereon and the signal developed by the first detector is subtracted from the signal developed by the record detector to provide a phase contrast signal. (auth)

Epifluorescence light collection for multiphoton microscopic endoscopy

NASA Astrophysics Data System (ADS)

Brown, Christopher M.; Rivera, David R.; Xu, Chris; Webb, Watt W.

2011-03-01

Multiphoton microscopic endoscopy (MPM-E) is a promising medical in vivo diagnostic imaging technique because it captures intrinsic fluorescence and second harmonic generation signals to reveal anatomical and histological information about disease states in tissue. However, maximizing light collection from multiphoton endoscopes remains a challenge: weak nonlinear emissions from endogenous structures, miniature optics, large imaging depths, and light scattering in tissue all hamper light collection. The quantity of light that may be collected using a dual-clad fiber system from scattering phantoms that mimic the properties of the in vivo environment is measured. In this experiment, 800nm excitation light from a Ti:Sapphire laser is dispersion compensated and focused through a SM800 optical fiber and lens system into the tissue phantom. Emission light from the phantom passes through the lens system, reflects off the dichroic and is then collected by a second optical fiber actuated by a micromanipulator. The lateral position of the collection fiber varies, measuring the distribution of emitted light 2000μm on either side of the focal point reimaged to the object plane. This spatial collection measurement is performed at depths up to 200μm from the phantom surface. The tissue phantoms are composed of a 15.8 μM fluorescein solution mixed with microspheres, approximating the scattering properties of human bladder and dermis tissue. Results show that commercially available dual-clad optical fibers collect more than 47% of the total emission returning to the object plane from both phantoms. Based on these results, initial MPM-E devices will image the surface of epithelial tissues.

Pseudomonas aeruginosa Infectious Keratitis in a High Oxygen Transmissible Rigid Contact Lens Rabbit Model

PubMed Central

Wei, Cynthia; Zhu, Meifang; Petroll, W. Matthew; Robertson, Danielle M.

2014-01-01

Purpose. To establish a rabbit model of infectious Pseudomonas aeruginosa keratitis using ultrahigh oxygen transmissible rigid lenses and characterize the frequency and severity of infection when compared to a non–oxygen transmissible lens material. Methods. Rabbits were fit with rigid lenses composed of ultrahigh and non–oxygen transmissible materials. Prior to wear, lenses were inoculated with an invasive corneal isolate of P. aeruginosa stably conjugated to green fluorescent protein (GFP). Corneas were examined before and after lens wear using a modified Heidelberg Rostock Tomograph in vivo confocal microscope. Viable bacteria adherent to unworn and worn lenses were assessed by standard plate counts. The presence of P. aeruginosa-GFP and myeloperoxidase-labeled neutrophils in infected corneal tissue was evaluated using laser scanning confocal microscopy. Results. The frequency and severity of infectious keratitis was significantly greater with inoculated ultrahigh oxygen transmissible lenses. Infection severity was associated with increasing neutrophil infiltration and in severe cases, corneal melting. In vivo confocal microscopic analysis of control corneas following lens wear confirmed that hypoxic lens wear was associated with mechanical surface damage, whereas no ocular surface damage was evident in the high-oxygen lens group. Conclusions. These data indicate that in the absence of adequate tear clearance, the presence of P. aeruginosa trapped under the lens overrides the protective effects of oxygen on surface epithelial cells. These findings also suggest that alternative pathophysiological mechanisms exist whereby changes under the lens in the absence of frank hypoxic damage result in P. aeruginosa infection in the otherwise healthy corneal epithelium. PMID:25125601

Microscope-on-Chip Using Micro-Channel and Solid State Image Sensors

NASA Technical Reports Server (NTRS)

Wang, Yu

2000-01-01

Recently, Jet Propulsion Laboratory has invented and developed a miniature optical microscope, microscope-on-chip using micro-channel and solid state image sensors. It is lightweight, low-power, fast speed instrument, it has no image lens, does not need focus adjustment, and the total mass is less than 100g. A prototype has been built and demonstrated at JPL.

Fabrication of miniature elastomer lenses with programmable liquid mold for smartphone microscopy: curing polydimethylsiloxane with in situ curvature control.

PubMed

Karunakaran, Bhuvaneshwari; Tharion, Joseph; Dhawangale, Arvind Ramrao; Paul, Debjani; Mukherji, Soumyo

2018-02-01

Miniature lenses can transform commercial imaging systems, e.g., smartphones and webcams, into powerful, low-cost, handheld microscopes. To date, the reproducible fabrication of polymer lenses is still a challenge as they require controlled dispensing of viscous liquid. This paper reports a reproducible lens fabrication technique using liquid mold with programmable curvature and off-the-shelf materials. The lens curvature is controlled during fabrication by tuning the curvature of an interface of two immiscible liquids [polydimethylsiloxane (PDMS) and glycerol]. The curvature control is implemented using a visual feedback system, which includes a software-based guiding system to produce lenses of desired curvature. The technique allows PDMS lens fabrication of a wide range of sizes and focal lengths, within 20 min. The fabrication of two lens diameters: 1 and 5 mm with focal lengths ranging between 1.2 and 11 mm are demonstrated. The lens surface and bulk quality check performed using X-ray microtomography and atomic force microscopy reveal that the lenses are suitable for optical imaging. Furthermore, a smartphone microscope with ∼1.4-μm resolution is developed using a self-assembly of a single high power fabricated lens and microaperture. The lenses have various potential applications, e.g., optofluidics, diagnostics, forensics, and surveillance. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Antony van Leeuwenhoek's microscopes and other scientific instruments: new information from the Delft archives.

PubMed

Zuidervaart, Huib J; Anderson, Douglas

2016-07-01

This paper discusses the scientific instruments made and used by the microscopist Antony van Leeuwenhoek (1632-1723). The immediate cause of our study was the discovery of an overlooked document from the Delft archive: an inventory of the possessions that were left in 1745 after the death of Leeuwenhoek's daughter Maria. This list sums up which tools and scientific instruments Leeuwenhoek possessed at the end of his life, including his famous microscopes. This information, combined with the results of earlier historical research, gives us new insights about the way Leeuwenhoek began his lens grinding and how eventually he made his best lenses. It also teaches us more about Leeuwenhoek's work as a surveyor and a wine gauger. A further investigation of the 1747 sale of Leeuwenhoek's 531 single lens microscopes has not only led us to the identification of nearly all buyers, but also has provided us with some explanation about why only a dozen of this large number of microscopes has survived.

Remote focusing in confocal microscopy by means of a modified Alvarez lens.

PubMed

Bawart, M; Jesacher, A; Bernet, S; Ritsch-Marte, M

2018-06-22

Alvarez lenses are actuated lens-pairs which allow one to tune the optical power by mechanical displacement of subelements. Here, we show that a recently realized modified Alvarez lens design which does not require mechanical actuation can be integrated into a confocal microscope. Instead of mechanically moving them, the sublenses are imaged onto each other in a 4f-configuration, where the lateral image shift leading to a change in optical power is created by a galvo-mirror. The avoidance of mechanical lens shifts leads to a large speed gain for axial (and hence also 3D) image scans compared to classical Alvarez lenses. We demonstrate that the suggested operation principle is compatible with confocal microscopy. In order to optimize the system, we have drawn advantage of the flexibility a liquid-crystal spatial light modulator offers for the implementation. For given specifications, dedicated diffractive optical elements or freeform elements can be used in combination with resonant galvo-scanners or acousto-optic beam deflectors, to achieve even faster z-scans than reported here, reaching video rate. © 2018 The Authors Journal of Microscopy © 2018 Royal Microscopical Society.

Low-cost mobile phone microscopy with a reversed mobile phone camera lens.

PubMed

Switz, Neil A; D'Ambrosio, Michael V; Fletcher, Daniel A

2014-01-01

The increasing capabilities and ubiquity of mobile phones and their associated digital cameras offer the possibility of extending low-cost, portable diagnostic microscopy to underserved and low-resource areas. However, mobile phone microscopes created by adding magnifying optics to the phone's camera module have been unable to make use of the full image sensor due to the specialized design of the embedded camera lens, exacerbating the tradeoff between resolution and field of view inherent to optical systems. This tradeoff is acutely felt for diagnostic applications, where the speed and cost of image-based diagnosis is related to the area of the sample that can be viewed at sufficient resolution. Here we present a simple and low-cost approach to mobile phone microscopy that uses a reversed mobile phone camera lens added to an intact mobile phone to enable high quality imaging over a significantly larger field of view than standard microscopy. We demonstrate use of the reversed lens mobile phone microscope to identify red and white blood cells in blood smears and soil-transmitted helminth eggs in stool samples.

Low-Cost Mobile Phone Microscopy with a Reversed Mobile Phone Camera Lens

PubMed Central

Fletcher, Daniel A.

2014-01-01

The increasing capabilities and ubiquity of mobile phones and their associated digital cameras offer the possibility of extending low-cost, portable diagnostic microscopy to underserved and low-resource areas. However, mobile phone microscopes created by adding magnifying optics to the phone's camera module have been unable to make use of the full image sensor due to the specialized design of the embedded camera lens, exacerbating the tradeoff between resolution and field of view inherent to optical systems. This tradeoff is acutely felt for diagnostic applications, where the speed and cost of image-based diagnosis is related to the area of the sample that can be viewed at sufficient resolution. Here we present a simple and low-cost approach to mobile phone microscopy that uses a reversed mobile phone camera lens added to an intact mobile phone to enable high quality imaging over a significantly larger field of view than standard microscopy. We demonstrate use of the reversed lens mobile phone microscope to identify red and white blood cells in blood smears and soil-transmitted helminth eggs in stool samples. PMID:24854188

DUV-microscope objectives: technology driver that forces the production to switch from the micrometer scale to the nanometer scale

NASA Astrophysics Data System (ADS)

Sure, Thomas; Bauer, Tobias; Heil, Joachim; Wesner, Joachim

2005-10-01

Cemented doublets and triplets can not be used for objectives working at wavelengths of 248 nm and shorter, because the optical cement can not withstand the high photon energies. It will be shown that high NA deep UV objectives can be designed and built successfully with the help of air spaced doublets. Assuring Strehl ratios above 95% enforces very tight tolerances. For example the distance error of the lens vertex to its mount has to be less than 1 μm. This calls for a new manufacturing precision never realized before in series production. We show how a white light Mirau interferometer can be used to measure lens vertex positions with an accuracy of 200 nm. We also demonstrate how the fine-tuning process can be optimized by using a "simulated star test", where the point-spread function is calculated in real time with a FFT-algorithm from the optical path difference data, acquired by a Twyman-Green interferometer. To realize the required precision, today various measurement techniques and production processes are used. Picking up the subgroups on different machining tools and measurement systems will loosen the accuracy. Here, we present the concept and the layout of a new manufacturing tool where we implemented the different measurement techniques needed in one CNC machining center. This tool is able to 1) adjust automatically the optical axis of the subgroups related to the machining axis better than 0.5 μm with the help of the stick-slip effect where a mechanical impulse is transferred by an electromagnetically driven hammer, 2) measure the lens vertex relative to the shoulder of the mount with an accuracy of 250 nm and 3) do all steps which are necessary to process the lens mount within the accuracies described above.

Microscopy illumination engineering using a low-cost liquid crystal display.

PubMed

Guo, Kaikai; Bian, Zichao; Dong, Siyuan; Nanda, Pariksheet; Wang, Ying Min; Zheng, Guoan

2015-02-01

Illumination engineering is critical for obtaining high-resolution, high-quality images in microscope settings. In a typical microscope, the condenser lens provides sample illumination that is uniform and free from glare. The associated condenser diaphragm can be manually adjusted to obtain the optimal illumination numerical aperture. In this paper, we report a programmable condenser lens for active illumination control. In our prototype setup, we used a $15 liquid crystal display as a transparent spatial light modulator and placed it at the back focal plane of the condenser lens. By setting different binary patterns on the display, we can actively control the illumination and the spatial coherence of the microscope platform. We demonstrated the use of such a simple scheme for multimodal imaging, including bright-field microscopy, darkfield microscopy, phase-contrast microscopy, polarization microscopy, 3D tomographic imaging, and super-resolution Fourier ptychographic imaging. The reported illumination engineering scheme is cost-effective and compatible with most existing platforms. It enables a turnkey solution with high flexibility for researchers in various communities. From the engineering point-of-view, the reported illumination scheme may also provide new insights for the development of multimodal microscopy and Fourier ptychographic imaging.

3D on-chip microscopy of optically cleared tissue

NASA Astrophysics Data System (ADS)

Zhang, Yibo; Shin, Yoonjung; Sung, Kevin; Yang, Sam; Chen, Harrison; Wang, Hongda; Teng, Da; Rivenson, Yair; Kulkarni, Rajan P.; Ozcan, Aydogan

2018-02-01

Traditional pathology relies on tissue biopsy, micro-sectioning, immunohistochemistry and microscopic imaging, which are relatively expensive and labor-intensive, and therefore are less accessible in resource-limited areas. Low-cost tissue clearing techniques, such as the simplified CLARITY method (SCM), are promising to potentially reduce the cost of disease diagnosis by providing 3D imaging and phenotyping of thicker tissue samples with simpler preparation steps. However, the mainstream imaging approach for cleared tissue, fluorescence microscopy, suffers from high-cost, photobleaching and signal fading. As an alternative approach to fluorescence, here we demonstrate 3D imaging of SCMcleared tissue using on-chip holography, which is based on pixel-super-resolution and multi-height phase recovery algorithms to digitally compute the sample's amplitude and phase images at various z-slices/depths through the sample. The tissue clearing procedures and the lens-free imaging system were jointly optimized to find the best illumination wavelength, tissue thickness, staining solution pH, and the number of hologram heights to maximize the imaged tissue volume, minimize the amount of acquired data, while maintaining a high contrast-to-noise ratio for the imaged cells. After this optimization, we achieved 3D imaging of a 200-μm thick cleared mouse brain tissue over a field-of-view of <20mm2 , and the resulting 3D z-stack agrees well with the images acquired with a scanning lens-based microscope (20× 0.75NA). Moreover, the lens-free microscope achieves an order-of-magnitude better data efficiency compared to its lens-based counterparts for volumetric imaging of samples. The presented low-cost and high-throughput lens-free tissue imaging technique enabled by CLARITY can be used in various biomedical applications in low-resource-settings.

Aligning Arrays of Lenses and Single-Mode Optical Fibers

NASA Technical Reports Server (NTRS)

Liu, Duncan

2004-01-01

A procedure now under development is intended to enable the precise alignment of sheet arrays of microscopic lenses with the end faces of a coherent bundle of as many as 1,000 single-mode optical fibers packed closely in a regular array (see Figure 1). In the original application that prompted this development, the precise assembly of lenses and optical fibers serves as a single-mode spatial filter for a visible-light nulling interferometer. The precision of alignment must be sufficient to limit any remaining wavefront error to a root-mean-square value of less than 1/10 of a wavelength of light. This wavefront-error limit translates to requirements to (1) ensure uniformity of both the lens and fiber arrays, (2) ensure that the lateral distance from the central axis of each lens and the corresponding optical fiber is no more than a fraction of a micron, (3) angularly align the lens-sheet planes and the fiber-bundle end faces to within a few arc seconds, and (4) axially align the lenses and the fiber-bundle end faces to within tens of microns of the focal distance. Figure 2 depicts the apparatus used in the alignment procedure. The beam of light from a Zygo (or equivalent) interferometer is first compressed by a ratio of 20:1 so that upon its return to the interferometer, the beam will be magnified enough to enable measurement of wavefront quality. The apparatus includes relay lenses that enable imaging of the arrays of microscopic lenses in a charge-coupled-device (CCD) camera that is part of the interferometer. One of the arrays of microscopic lenses is mounted on a 6-axis stage, in proximity to the front face of the bundle of optical fibers. The bundle is mounted on a separate stage. A mirror is attached to the back face of the bundle of optical fibers for retroreflection of light. When a microscopic lens and a fiber are aligned with each other, the affected portion of the light is reflected back by the mirror, recollimated by the microscopic lens, transmitted through the relay lenses and the beam compressor/expander, then split so that half goes to a detector and half to the interferometer. The output of the detector is used as a feedback control signal for the six-axis stage to effect alignment.

Thin laser light sheet microscope for microbial oceanography

NASA Astrophysics Data System (ADS)

Fuchs, Eran; Jaffe, Jules S.; Long, Richard A.; Azam, Farooq

2002-01-01

Despite a growing need, oceanographers are limited by existing technological constrains and are unable to observe aquatic microbes in their natural setting. In order to provide a simple and easy to implement solution for such studies, a new Thin Light Sheet Microscope (TLSM) has been developed. The TLSM utilizes a well-defined sheet of laser light, which has a narrow (23 micron) axial dimension over a 1 mm x 1 mm field of view. This light sheet is positioned precisely within the depth of field of the microscope’s objective lens. The technique thus utilizes conventional microscope optics but replaces the illumination system. The advantages of the TLSM are two-fold: First, it concentrates light only where excitation is needed, thus maximizing the efficiency of the illumination source. Secondly, the TLSM maximizes image sharpness while at the same time minimizing the level of background noise. Particles that are not located within the objective's depth of field are not illuminated and therefore do not contribute to an out-of-focus image. Images from a prototype system that used SYBR Green I fluorescence stain in order to localize single bacteria are reported. The bacteria were in a relatively large and undisturbed volume of 4ml, which contained natural seawater. The TLSM can be used for fresh water studies of bacteria with no modification. The microscope permits the observation of interactions at the microscale and has potential to yield insights into how microbes structure pelagic ecosystems.

Optimal integral force feedback for active vibration control

NASA Astrophysics Data System (ADS)

Teo, Yik R.; Fleming, Andrew J.

2015-11-01

This paper proposes an improvement to Integral Force Feedback (IFF), which is a popular method for active vibration control of structures and mechanical systems. Benefits of IFF include robustness, guaranteed stability and simplicity. However, the maximum damping performance is dependent on the stiffness of the system; hence, some systems cannot be adequately controlled. In this paper, an improvement to the classical force feedback control scheme is proposed. The improved method achieves arbitrary damping for any mechanical system by introducing a feed-through term. The proposed improvement is experimentally demonstrated by actively damping an objective lens assembly for a high-speed confocal microscope.

Curiosity's Mars Hand Lens Imager (MAHLI): Inital Observations and Activities

NASA Technical Reports Server (NTRS)

Edgett, K. S.; Yingst, R. A.; Minitti, M. E.; Robinson, M. L.; Kennedy, M. R.; Lipkaman, L. J.; Jensen, E. H.; Anderson, R. C.; Bean, K. M.; Beegle, L. W.;

Back focal plane microscopic ellipsometer with internal reflection geometry

NASA Astrophysics Data System (ADS)

Otsuki, Soichi; Murase, Norio; Kano, Hiroshi

2013-05-01

A back focal plane (BFP) ellipsometer is presented to measure a thin film on a cover glass using an oil-immersion high-numerical-aperture objective lens. The internal reflection geometry lowers the pseudo Brewster angle (ϕB) to the range over which the light distribution is observed in BFP of the objective. A calculation based on Mueller matrix was developed to compute ellipsometric parameters from the intensity distribution on BFP. The center and radius of the partial reflection region below the critical angle were determined and used to define a polar coordinate on BFP. Harmonic components were computed from the intensities along the azimuth direction and transformed to ellipsometric parameters at multiple incident angles around ϕB. The refractive index and thickness of the film and the contributions of the objective effect were estimated at the same time by fitting.

An inexpensive programmable illumination microscope with active feedback

PubMed Central

Tompkins, Nathan; Fraden, Seth

2016-01-01

We have developed a programmable illumination system capable of tracking and illuminating numerous objects simultaneously using only low-cost and reused optical components. The active feedback control software allows for a closed-loop system that tracks and perturbs objects of interest automatically. Our system uses a static stage where the objects of interest are tracked computationally as they move across the field of view allowing for a large number of simultaneous experiments. An algorithmically determined illumination pattern can be applied anywhere in the field of view with simultaneous imaging and perturbation using different colors of light to enable spatially and temporally structured illumination. Our system consists of a consumer projector, camera, 35-mm camera lens, and a small number of other optical and scaffolding components. The entire apparatus can be assembled for under $4,000. PMID:27642182

Expression of the type VI intermediate filament proteins CP49 and filensin in the mouse lens epithelium.

PubMed

FitzGerald, Paul; Sun, Ning; Shibata, Brad; Hess, John F

2016-01-01

The differentiated lens fiber cell assembles a filamentous cytoskeletal structure referred to as the beaded filament (BF). The BF requires CP49 (bfsp2) and filensin (bfsp1) for assembly, both of which are highly divergent members of the large intermediate filament (IF) family of proteins. Thus far, these two proteins have been reported only in the differentiated lens fiber cell. For this reason, both proteins have been considered robust markers of fiber cell differentiation. We report here that both proteins are also expressed in the mouse lens epithelium, but only after 5 weeks of age. Localization of CP49 was achieved with immunocytochemical probing of wild-type, CP49 knockout, filensin knockout, and vimentin knockout mice, in sections and in the explanted lens epithelium, at the light microscope and electron microscope levels. The relationship between CP49 and other cytoskeletal elements was probed using fluorescent phalloidin, as well as with antibodies to vimentin, GFAP, and α-tubulin. The relationship between CP49 and the aggresome was probed with antibodies to γ-tubulin, ubiquitin, and HDAC6. CP49 and filensin were expressed in the mouse lens epithelium, but only after 5 weeks of age. At the light microscope level, these two proteins colocalize to a large tubular structure, approximately 7 × 1 μm, which was typically present at one to two copies per cell. This structure is found in the anterior and anterolateral lens epithelium, including the zone where mitosis occurs. The structure becomes smaller and largely undetectable closer to the equator where the cell exits the cell cycle and commits to fiber cell differentiation. This structure bears some resemblance to the aggresome and is reactive with antibodies to HDAC6, a marker for the aggresome. However, the structure does not colocalize with antibodies to γ-tubulin or ubiquitin, also markers for the aggresome. The structure also colocalizes with actin but appears to largely exclude vimentin and α-tubulin. In the CP49 and filensin knockouts, this structure is absent, confirming the identity of CP49 and filensin in this structure, and suggesting a requirement for the physiologic coassembly of CP49 and filensin. CP49 and filensin have been considered robust markers for mouse lens fiber cell differentiation. The data reported here, however, document both proteins in the mouse lens epithelium, but only after 5 weeks of age, when lens epithelial growth and mitotic activity have slowed. Because of this, CP49 and filensin must be considered markers of differentiation for both fiber cells and the lens epithelium in the mouse. In addition, to our knowledge, no other protein has been shown to emerge so late in the development of the mouse lens epithelium, suggesting that lens epithelial differentiation may continue well into post-natal life. If this structure is related to the aggresome, it is a rare, or perhaps unique example of a large, stable aggresome in wild-type tissue.

Gradient descent algorithm applied to wavefront retrieval from through-focus images by an extreme ultraviolet microscope with partially coherent source

DOE PAGES

Yamazoe, Kenji; Mochi, Iacopo; Goldberg, Kenneth A.

2014-12-01

The wavefront retrieval by gradient descent algorithm that is typically applied to coherent or incoherent imaging is extended to retrieve a wavefront from a series of through-focus images by partially coherent illumination. For accurate retrieval, we modeled partial coherence as well as object transmittance into the gradient descent algorithm. However, this modeling increases the computation time due to the complexity of partially coherent imaging simulation that is repeatedly used in the optimization loop. To accelerate the computation, we incorporate not only the Fourier transform but also an eigenfunction decomposition of the image. As a demonstration, the extended algorithm is appliedmore » to retrieve a field-dependent wavefront of a microscope operated at extreme ultraviolet wavelength (13.4 nm). The retrieved wavefront qualitatively matches the expected characteristics of the lens design.« less

Underwater microscopy for in situ studies of benthic ecosystems

NASA Astrophysics Data System (ADS)

Mullen, Andrew D.; Treibitz, Tali; Roberts, Paul L. D.; Kelly, Emily L. A.; Horwitz, Rael; Smith, Jennifer E.; Jaffe, Jules S.

2016-07-01

Microscopic-scale processes significantly influence benthic marine ecosystems such as coral reefs and kelp forests. Due to the ocean's complex and dynamic nature, it is most informative to study these processes in the natural environment yet it is inherently difficult. Here we present a system capable of non-invasively imaging seafloor environments and organisms in situ at nearly micrometre resolution. We overcome the challenges of underwater microscopy through the use of a long working distance microscopic objective, an electrically tunable lens and focused reflectance illumination. The diver-deployed instrument permits studies of both spatial and temporal processes such as the algal colonization and overgrowth of bleaching corals, as well as coral polyp behaviour and interspecific competition. By enabling in situ observations at previously unattainable scales, this instrument can provide important new insights into micro-scale processes in benthic ecosystems that shape observed patterns at much larger scales.

Gradient descent algorithm applied to wavefront retrieval from through-focus images by an extreme ultraviolet microscope with partially coherent source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamazoe, Kenji; Mochi, Iacopo; Goldberg, Kenneth A.

The wavefront retrieval by gradient descent algorithm that is typically applied to coherent or incoherent imaging is extended to retrieve a wavefront from a series of through-focus images by partially coherent illumination. For accurate retrieval, we modeled partial coherence as well as object transmittance into the gradient descent algorithm. However, this modeling increases the computation time due to the complexity of partially coherent imaging simulation that is repeatedly used in the optimization loop. To accelerate the computation, we incorporate not only the Fourier transform but also an eigenfunction decomposition of the image. As a demonstration, the extended algorithm is appliedmore » to retrieve a field-dependent wavefront of a microscope operated at extreme ultraviolet wavelength (13.4 nm). The retrieved wavefront qualitatively matches the expected characteristics of the lens design.« less

Computational Sensing of Staphylococcus aureus on Contact Lenses Using 3D Imaging of Curved Surfaces and Machine Learning.

PubMed

Veli, Muhammed; Ozcan, Aydogan

2018-03-27

We present a cost-effective and portable platform based on contact lenses for noninvasively detecting Staphylococcus aureus, which is part of the human ocular microbiome and resides on the cornea and conjunctiva. Using S. aureus-specific antibodies and a surface chemistry protocol that is compatible with human tears, contact lenses are designed to specifically capture S. aureus. After the bacteria capture on the lens and right before its imaging, the captured bacteria are tagged with surface-functionalized polystyrene microparticles. These microbeads provide sufficient signal-to-noise ratio for the quantification of the captured bacteria on the contact lens, without any fluorescent labels, by 3D imaging of the curved surface of each lens using only one hologram taken with a lens-free on-chip microscope. After the 3D surface of the contact lens is computationally reconstructed using rotational field transformations and holographic digital focusing, a machine learning algorithm is employed to automatically count the number of beads on the lens surface, revealing the count of the captured bacteria. To demonstrate its proof-of-concept, we created a field-portable and cost-effective holographic microscope, which weighs 77 g, controlled by a laptop. Using daily contact lenses that are spiked with bacteria, we demonstrated that this computational sensing platform provides a detection limit of ∼16 bacteria/μL. This contact-lens-based wearable sensor can be broadly applicable to detect various bacteria, viruses, and analytes in tears using a cost-effective and portable computational imager that might be used even at home by consumers.

Multiplex coherent anti-Stokes Raman scattering microspectroscopy for monitoring molecular structural change in biological samples

NASA Astrophysics Data System (ADS)

Ohta, Takayuki; Hashizume, Hiroshi; Takeda, Keigo; Ishikawa, Kenji; Ito, Masafumi; Hori, Masaru

2014-10-01

Biological applications employing non-equilibrium plasma processing has been attracted much attention. It is essential to monitor the changes in an intracellular structure of the cell during the plasma exposure. In this study, we have analyzed the molecular structure of biological samples using multiplex coherent anti-Stokes Raman scattering (CARS) microspectroscopy. Two picosecond pulse lasers with fundamental (1064 nm) or the supercontinuum (460-2200 nm) were employed as a pump and Stokes beams of multiplex CARS microspectroscopy, respectively. The pump and the Stokes laser beams were collinearly overlapped and tightly focused into a sample using an objective lens of high numerical aperture. The CARS signal was collected by another microscope objective lens which is placed facing the first one. After passing through a short pass filter, the signal was dispersed by a polychromator, and was detected by a charge-coupled device camera. The sample was sandwiched by a coverslip and a glass bottom dish for the measurements and was placed on a piezo stage. The CARS signals of the quinhydrone crystal at 1655, 1584, 1237 and 1161 cm-1 were assigned to the C-C, C =O stretching, O-H and C-O stretching vibrational modes, respectively.

An Affordable Microsurgical Training System for a Beginning Neurosurgeon: How to Realize the Self-Training Laboratory.

PubMed

Chung, Sang-Bong; Ryu, Jiwook; Chung, Yeongu; Lee, Sung Ho; Choi, Seok Keun

2017-09-01

To provide detailed information about how to realize a self-training laboratory with cost-effective microsurgical instruments, especially pertinent for the novice trainee. Our training model is designed to allow the practice of the microsurgery skills in an efficient and cost-effective manner. A used stereoscopic microscope is prepared for microsurgical training. A sufficient working distance for microsurgical practice is obtained by attaching an auxiliary objective lens. The minimum instrument list includes 2 jeweler's forceps, iris scissors, and alligator clips. The iris scissors and alligator clip provide good alternatives to micro-scissors and microvascular clamp. The short time needed to set up the microscope and suture the gauze with micro-forceps makes the training model suitable for daily practice. It takes about 15 minutes to suture 10 neighboring fibers of the gauze with 10-0 nylon; thus, training can be completed more quickly. We have developed an inexpensive and efficient micro-anastomosis training system using a stereoscopic microscope and minimal micro-instruments. Especially useful for novice trainees, this system provides high accessibility for microsurgical training. Copyright © 2017 Elsevier Inc. All rights reserved.

Electron microscope phase enhancement

DOEpatents

Jin, Jian; Glaeser, Robert M.

2010-06-15

A microfabricated electron phase shift element is used for modifying the phase characteristics of an electron beam passing though its center aperture, while not affecting the more divergent portion of an incident beam to selectively provide a ninety-degree phase shift to the unscattered beam in the back focal plan of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. One application of the element is to increase the contrast of an electron microscope for viewing weakly scattering samples while in focus. Typical weakly scattering samples include biological samples such as macromolecules, or perhaps cells. Preliminary experimental images demonstrate that these devices do apply a ninety degree phase shift as expected. Electrostatic calculations have been used to determine that fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature-size aperture is about 5:1. Calculations are underway to determine the feasibility of aspect smaller aspect ratios of about 3:1 and about 2:1.

Variations in contrast of scanning electron microscope images for microstructure analysis of Si-based semiconductor materials.

PubMed

Itakura, Masaru; Kuwano, Noriyuki; Sato, Kaoru; Tachibana, Shigeaki

2010-08-01

Image contrasts of Si-based semiconducting materials have been investigated by using the latest scanning electron microscope with various detectors under a range of experimental conditions. Under a very low accelerating voltage (500 V), we obtained a good image contrast between crystalline SiGe whiskers and the amorphous matrix using an in-lens secondary electron (SE) detector, while the conventional topographic SE image and the compositional backscattered electron (BSE) image gave no distinct contrast. By using an angular-selective BSE (AsB) detector for wide-angle scattered BSE, on the other hand, the crystal grains in amorphous matrix can be clearly visualized as 'channelling contrast'. The image contrast is very similar to that of their transmission electron microscope image. The in-lens SE (true SE falling dots SE1) and the AsB (channelling) contrasts are quite useful to distinguish crystalline parts from amorphous ones.

Direct microscopic image and measurement of the atomization process of a port fuel injector

NASA Astrophysics Data System (ADS)

Esmail, Mohamed; Kawahara, Nobuyuki; Tomita, Eiji; Sumida, Mamoru

2010-07-01

The main objective of this study is to observe and investigate the phenomena of atomization, i.e. the fuel break-up process very close to the nozzle exit of a practical port fuel injector (PFI). In order to achieve this objective, direct microscopic images of the atomization process were obtained using an ultra-high-speed video camera that could record 102 frames at rates of up to 1 Mfps, coupled with a long-distance microscope and Barlow lens. The experiments were carried out using a PFI in a closed chamber at atmospheric pressure. Time-series images of the spray behaviour were obtained with a high temporal resolution using backlighting. The direct microscopic images of a liquid column break-up were compared with experimental results from laser-induced exciplex fluorescence (LIEF), and the wavelength obtained from the experimental results compared with that predicated from the Kelvin-Helmholtz break-up model. The droplet size diameters from a ligament break-up were compared with results predicated from Weber's analysis. Furthermore, experimental results of the mean droplet diameter from a direct microscopic image were compared with the results obtained from phase Doppler anemometry (PDA) experimental results. Three conclusions were obtained from this study. The atomization processes and detailed characterizations of the break-up of a liquid column were identified; the direct microscopic image results were in good agreement with the results obtained from LIEF, experimental results of the wavelength were in good agreement with those from the Kelvin-Helmholtz break-up model. The break-up process of liquid ligaments into droplets was investigated, and Weber's analysis of the predicated droplet diameter from ligament break-up was found to be applicable only at larger wavelengths. Finally, the direct microscopic image method and PDA method give qualitatively similar trends for droplet size distribution and quantitatively similar values of Sauter mean diameter.

Effects of multipurpose solutions on the adhesion of Acanthamoeba to rigid gas permeable contact lenses.

PubMed

Lee, Ga-Hyun; Yu, Hak-Sun; Lee, Ji-Eun

2016-03-01

To evaluate the effect of multipurpose contact lens care solutions (MPSs) on the adhesion of Acanthamoeba to rigid gas permeable (RGP) contact lenses. Acanthamoeba castellanii (AC) trophozoites were inoculated onto untreated RGP contact lenses (FP, Extra, or Menicon Z), and numbers of trophozoites adhering to lenses were counted under a phase contrast microscope at 18 h post-inoculation (controls). Similarly, adhering trophozoites were counted at 6 h post-inoculation on each of the three RGP lens types with one of three MPSs (Boston Simplus, Menicare Plus, and O2 Care). Scanning electron microscopic examinations were performed to compare lens surfaces. Adhesion of AC trophozoites to untreated FP was greater than to untreated Extra or Menicon Z. Surfaces of Extra and Menicon Z lenses were waxier, smoother, and more homogeneous than those of FP lenses. After treatment with Boston Simplus, adhesion of AC trophozoites was significantly reduced for all lens types as compared with controls (p < 0.0001). Treatments with Menicare Plus or O2 Care reduced the number of adherent AC trophozoites significantly on FP lenses only as compared with controls (p < 0.0001). The adhesion rates of AC trophozoites to RGP lenses depended on lens surfaces. Boston Simplus reduced the adhesion rate of AC trophozoites more than Menicare Plus or O2 Care. Appropriate RGP lens and MPS selection could decrease the prevalence of Acanthamoeba keratitis. © 2016 The Authors Ophthalmic & Physiological Optics © 2016 The College of Optometrists.

Computational imaging of sperm locomotion.

PubMed

Daloglu, Mustafa Ugur; Ozcan, Aydogan

2017-08-01

Not only essential for scientific research, but also in the analysis of male fertility and for animal husbandry, sperm tracking and characterization techniques have been greatly benefiting from computational imaging. Digital image sensors, in combination with optical microscopy tools and powerful computers, have enabled the use of advanced detection and tracking algorithms that automatically map sperm trajectories and calculate various motility parameters across large data sets. Computational techniques are driving the field even further, facilitating the development of unconventional sperm imaging and tracking methods that do not rely on standard optical microscopes and objective lenses, which limit the field of view and volume of the semen sample that can be imaged. As an example, a holographic on-chip sperm imaging platform, only composed of a light-emitting diode and an opto-electronic image sensor, has emerged as a high-throughput, low-cost and portable alternative to lens-based traditional sperm imaging and tracking methods. In this approach, the sample is placed very close to the image sensor chip, which captures lensfree holograms generated by the interference of the background illumination with the light scattered from sperm cells. These holographic patterns are then digitally processed to extract both the amplitude and phase information of the spermatozoa, effectively replacing the microscope objective lens with computation. This platform has further enabled high-throughput 3D imaging of spermatozoa with submicron 3D positioning accuracy in large sample volumes, revealing various rare locomotion patterns. We believe that computational chip-scale sperm imaging and 3D tracking techniques will find numerous opportunities in both sperm related research and commercial applications. © The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Role of Aquaporin 0 in lens biomechanics.

PubMed

Sindhu Kumari, S; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G; Menon, Anil G; Mathias, Richard T; Varadaraj, Kulandaiappan

2015-07-10

Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5(-/-)), AQP0 KO (heterozygous KO: AQP0(+/-); homozygous KO: AQP0(-/-); all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0(+/-) lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to confer fiber cell shape, architecture and integrity. To our knowledge, this is the first report identifying the involvement of an aquaporin in lens biomechanics. Since accommodation is required in human lenses for proper focusing, alteration in the adhesion and/or water channel functions of AQP0 could contribute to presbyopia. Copyright © 2015 Elsevier Inc. All rights reserved.

Ex vivo measurement of postmortem tissue changes in the crystalline lens by Brillouin spectroscopy and confocal reflectance microscopy.

PubMed

Reiss, Stephan; Sperlich, K; Hovakimyan, M; Martius, P; Guthoff, R F; Stolz, H; Stachs, O

2012-08-01

Use of Brillouin spectroscopy in ophthalmology enables noninvasive, spatially resolved determination of the rheological properties of crystalline lens tissue. Furthermore, the Brillouin shift correlates with the protein concentration inside the lens. In vitro measurements on extracted porcine lenses demonstrate that results obtained with Brillouin spectroscopy depend strongly on time after death. The intensity of the Brillouin signal decreases significantly as early as 5 h postmortem. Moreover, the fluctuation of the Brillouin frequency shift inside the lens increases with postmortem time. Images of lens tissue taken with a confocal reflectance microscope between measurements reveal a degenerative aging process. These tissue changes correlate with our results from Brillouin spectroscopy. It is concluded that only in vivo measurements appropriately reflect the rheological properties of the eye lens and its protein concentration.

Open-source do-it-yourself multi-color fluorescence smartphone microscopy

PubMed Central

Sung, Yulung; Campa, Fernando; Shih, Wei-Chuan

2017-01-01

Fluorescence microscopy is an important technique for cellular and microbiological investigations. Translating this technique onto a smartphone can enable particularly powerful applications such as on-site analysis, on-demand monitoring, and point-of-care diagnostics. Current fluorescence smartphone microscope setups require precise illumination and imaging alignment which altogether limit its broad adoption. We report a multi-color fluorescence smartphone microscope with a single contact lens-like add-on lens and slide-launched total-internal-reflection guided illumination for three common tasks in investigative fluorescence microscopy: autofluorescence, fluorescent stains, and immunofluorescence. The open-source, simple and cost-effective design has the potential for do-it-yourself fluorescence smartphone microscopy. PMID:29188104

Note: optical optimization for ultrasensitive photon mapping with submolecular resolution by scanning tunneling microscope induced luminescence.

PubMed

Chen, L G; Zhang, C; Zhang, R; Zhang, X L; Dong, Z C

2013-06-01

We report the development of a custom scanning tunneling microscope equipped with photon collection and detection systems. The optical optimization includes the comprehensive design of aspherical lens for light collimation and condensing, the sophisticated piezo stages for in situ lens adjustment inside ultrahigh vacuum, and the fiber-free coupling of collected photons directly onto the ultrasensitive single-photon detectors. We also demonstrate submolecular photon mapping for the molecular islands of porphyrin on Ag(111) under small tunneling currents down to 10 pA and short exposure time down to 1.2 ms/pixel. A high quantum efficiency up to 10(-2) was also observed.

Chapter 05: Basic characters used in the identification of wood with a hand lens

Treesearch

Alex Wiedenhoeft

2011-01-01

The characters presented in this chapter represent the minimal set of terms and concepts necessary to build skill and proficiency in wood identification with a hand lens. This list is not exhaustive, nor is it in complete agreement with the characters used by other authors, in other references, or in traditional microscopic wood anatomy.

Optics of wide-angle panoramic viewing system-assisted vitreous surgery.

PubMed

Chalam, Kakarla V; Shah, Vinay A

2004-01-01

The purpose of the article is to describe the optics of the contact wide-angle lens system with stereo-reinverter for vitreous surgery. A panoramic viewing system is made up of two components; an indirect ophthalmoscopy lens system for fundus image viewing, which is placed on the patient's cornea as a contact lens, and a separate removable prism system for reinversion of the image mounted on the microscope above the zooming system. The system provides a 104 degrees field of view in a phakic emmetropic eye with minification, which can be magnified by the operating microscope. It permits a binocular stereoptic view even through a small pupil (3 mm) or larger. In an air-filled phakic eye, field of view increases to approximately 130 degrees. The obtained image of the patient's fundus is reinverted to form true, erect, stereoscopic image by the reinversion system. In conclusion, this system permits wide-angle panoramic view of the surgical field. The contact lens neutralizes the optical irregularities of the corneal surface and allows improved visualization in eyes with irregular astigmatism induced by corneal scars. Excellent visualization is achieved in complex clinical situations such as miotic pupils, lenticular opacities, and in air-filled phakic eyes.

Compact OAM microscope for edge enhancement of biomedical and object samples

NASA Astrophysics Data System (ADS)

Gozali, Richard; Nguyen, Thien-An; Bendau, Ethan; Alfano, Robert R.

2017-09-01

The production of orbital angular momentum (OAM) by using a q-plate, which functions as an electrically tunable spatial frequency filter, provides a simple and efficient method of edge contrast in biological and medical sample imaging for histological evaluation of tissue, smears, and PAP smears. An instrument producing OAM, such as a q-plate, situated at the Fourier plane of a 4f lens system, similar to the use of a high-pass spatial filter, allows the passage of high spatial frequencies and enables the production of an image with highly illuminated edges contrasted against a dark background for both opaque and transparent objects. Compared with ordinary spiral phase plates and spatial light modulators, the q-plate has the added advantage of electric control and tunability.

Gabor domain optical coherence microscopy

NASA Astrophysics Data System (ADS)

Murali, Supraja

Time domain Optical Coherence Tomography (TD-OCT), first reported in 1991, makes use of the low temporal coherence properties of a NIR broadband laser to create depth sectioning of up to 2mm under the surface using optical interferometry and point to point scanning. Prior and ongoing work in OCT in the research community has concentrated on improving axial resolution through the development of broadband sources and speed of image acquisition through new techniques such as Spectral domain OCT (SD-OCT). In SD-OCT, an entire depth scan is acquired at once with a low numerical aperture (NA) objective lens focused at a fixed point within the sample. In this imaging geometry, a longer depth of focus is achieved at the expense of lateral resolution, which is typically limited to 10 to 20 mum. Optical Coherence Microscopy (OCM), introduced in 1994, combined the advantages of high axial resolution obtained in OCT with high lateral resolution obtained by increasing the NA of the microscope placed in the sample arm. However, OCM presented trade-offs caused by the inverse quadratic relationship between the NA and the DOF of the optics used. For applications requiring high lateral resolution, such as cancer diagnostics, several solutions have been proposed including the periodic manual re-focusing of the objective lens in the time domain as well as the spectral domain C-mode configuration in order to overcome the loss in lateral resolution outside the DOF. In this research, we report for the first time, high speed, sub-cellular imaging (lateral resolution of 2 mum) in OCM using a Gabor domain image processing algorithm with a custom designed and fabricated dynamic focus microscope interfaced to a Ti:Sa femtosecond laser centered at 800 nm within an SD-OCM configuration. It is envisioned that this technology will provide a non-invasive replacement for the current practice of multiple biopsies for skin cancer diagnosis. The research reported here presents three important advances to this technology all of which have been demonstrated in full functional hardware conceived and built during the course of this research. First, it has been demonstrated that the coherence gate created by the femtosecond laser can be coupled into a scanning optical microscope using optical design methods to include liquid lens technology that enables scanning below the surface of skin with no moving parts and at high resolution throughout a 2x2x2 mm imaging cube. Second, the integration the variable-focus liquid lens technology within a fixed-optics microscope custom optical design helped increase the working NA by an order of magnitude over the limitation imposed by the liquid lens alone. Thus, this design has enabled homogenous axial and lateral resolution at the micron-level (i.e., 2 mum) while imaging in the spectral domain, and still maintaining in vivo speeds. The latest images in biological specimens clearly demonstrate sub-cellular resolution in all dimensions throughout the imaging volume. Third, this new modality for data collection has been integrated with an automated Gabor domain image registration and fusion algorithm to provide full resolution images across the data cube in real-time. We refer to this overall OCM method as Gabor domain OCM (GD-OCM). These advantages place GD-OCM in a unique position with respect to the diagnosis of cancer, because when fully developed, it promises to enable fast and accurate screening for early symptoms that could lead to prevention. The next step for this technology is to apply it directly, in a clinical environment. This step is underway and is expected to be reported by the next generation of researchers within this group.

Mode-mismatched confocal thermal-lens microscope with collimated probe beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabrera, Humberto, E-mail: hcabrera@ictp.it; Centro Multidisciplinartio de Ciencias, Instituto Venezolano de Investigaciones Científicas; Korte, Dorota

2015-05-15

We report a thermal lens microscope (TLM) based on an optimized mode-mismatched configuration. It takes advantage of the coaxial counter propagating tightly focused excitation and collimated probe beams, instead of both focused at the sample, as it is in currently known TLM setups. A simple mathematical model that takes into account the main features of the instrument is presented. The confocal detection scheme and the introduction of highly collimated probe beam allow enhancing the versatility, limit of detection (LOD), and sensitivity of the instrument. The theory is experimentally verified measuring ethanol’s absorption coefficient at 532.8 nm. Additionally, the presented techniquemore » is applied for detection of ultra-trace amounts of Cr(III) in liquid solution. The achieved LOD is 1.3 ppb, which represents 20-fold enhancement compared to transmission mode spectrometric techniques and a 7.5-fold improvement compared to previously reported methods for Cr(III) based on thermal lens effect.« less

Objective Lens Optimized for Wavefront Delivery, Pupil Imaging, and Pupil Ghosting

NASA Technical Reports Server (NTRS)

Olzcak, Gene

2009-01-01

An interferometer objective lens (or diverger) may be used to transform a collimated beam into a diverging or converging beam. This innovation provides an objective lens that has diffraction-limited optical performance that is optimized at two sets of conjugates: imaging to the objective focus and imaging to the pupil. The lens thus provides for simultaneous delivery of a high-quality beam and excellent pupil resolution properties.

Expression of the type VI intermediate filament proteins CP49 and filensin in the mouse lens epithelium

PubMed Central

Sun, Ning; Shibata, Brad; Hess, John F.

2016-01-01

Purpose The differentiated lens fiber cell assembles a filamentous cytoskeletal structure referred to as the beaded filament (BF). The BF requires CP49 (bfsp2) and filensin (bfsp1) for assembly, both of which are highly divergent members of the large intermediate filament (IF) family of proteins. Thus far, these two proteins have been reported only in the differentiated lens fiber cell. For this reason, both proteins have been considered robust markers of fiber cell differentiation. We report here that both proteins are also expressed in the mouse lens epithelium, but only after 5 weeks of age. Methods Localization of CP49 was achieved with immunocytochemical probing of wild-type, CP49 knockout, filensin knockout, and vimentin knockout mice, in sections and in the explanted lens epithelium, at the light microscope and electron microscope levels. The relationship between CP49 and other cytoskeletal elements was probed using fluorescent phalloidin, as well as with antibodies to vimentin, GFAP, and α-tubulin. The relationship between CP49 and the aggresome was probed with antibodies to γ-tubulin, ubiquitin, and HDAC6. Results CP49 and filensin were expressed in the mouse lens epithelium, but only after 5 weeks of age. At the light microscope level, these two proteins colocalize to a large tubular structure, approximately 7 × 1 μm, which was typically present at one to two copies per cell. This structure is found in the anterior and anterolateral lens epithelium, including the zone where mitosis occurs. The structure becomes smaller and largely undetectable closer to the equator where the cell exits the cell cycle and commits to fiber cell differentiation. This structure bears some resemblance to the aggresome and is reactive with antibodies to HDAC6, a marker for the aggresome. However, the structure does not colocalize with antibodies to γ-tubulin or ubiquitin, also markers for the aggresome. The structure also colocalizes with actin but appears to largely exclude vimentin and α-tubulin. In the CP49 and filensin knockouts, this structure is absent, confirming the identity of CP49 and filensin in this structure, and suggesting a requirement for the physiologic coassembly of CP49 and filensin. Conclusions CP49 and filensin have been considered robust markers for mouse lens fiber cell differentiation. The data reported here, however, document both proteins in the mouse lens epithelium, but only after 5 weeks of age, when lens epithelial growth and mitotic activity have slowed. Because of this, CP49 and filensin must be considered markers of differentiation for both fiber cells and the lens epithelium in the mouse. In addition, to our knowledge, no other protein has been shown to emerge so late in the development of the mouse lens epithelium, suggesting that lens epithelial differentiation may continue well into post-natal life. If this structure is related to the aggresome, it is a rare, or perhaps unique example of a large, stable aggresome in wild-type tissue. PMID:27559293

Synthetic light-needle photoacoustic microscopy for extended depth of field (Conference Presentation)

NASA Astrophysics Data System (ADS)

Yang, Jiamiao; Gong, Lei; Xu, Xiao; Hai, Pengfei; Suzuki, Yuta; Wang, Lihong V.

2017-03-01

Photoacoustic microscopy (PAM) has been extensively applied in biomedical study because of its ability to visualize tissue morphology and physiology in vivo in three dimensions (3D). However, conventional PAM suffers from a rapidly decreasing resolution away from the focal plane because of the limited depth of focus of an objective lens, which deteriorates the volumetric imaging quality inevitably. Here, we propose a novel method to synthesize an ultra-long light needle to extend a microscope's depth of focus beyond its physical limitations with wavefront engineering method. Furthermore, it enables an improved lateral resolution that exceeds the diffraction limit of the objective lens. The virtual light needle can be flexibly synthesized anywhere throughout the imaging volume without mechanical scanning. Benefiting from these advantages, we developed a synthetic light needle photoacoustic microscopy (SLN-PAM) to achieve an extended depth of field (DOF), sub-diffraction and motionless volumetric imaging. The DOF of our SLN-PAM system is up to 1800 µm, more than 30-fold improvement over that gained by conventional PAM. Our system also achieves the lateral resolution of 1.8 µm (characterized at 532 nm and 0.1 NA objective), about 50% higher than the Rayleigh diffraction limit. Its superior imaging performance was demonstrated by 3D imaging of both non-biological and biological samples. This extended DOF, sub-diffraction and motionless 3D PAM will open up new opportunities for potential biomedical applications.

EnLightenment: High resolution smartphone microscopy as an educational and public engagement platform.

PubMed

Wicks, Laura C; Cairns, Gemma S; Melnyk, Jacob; Bryce, Scott; Duncan, Rory R; Dalgarno, Paul A

2017-01-01

We developed a simple, cost-effective smartphone microscopy platform for use in educational and public engagement programs. We demonstrated its effectiveness, and potential for citizen science through a national imaging initiative, EnLightenment . The cost effectiveness of the instrument allowed for the program to deliver over 500 microscopes to more than 100 secondary schools throughout Scotland, targeting 1000's of 12-14 year olds. Through careful, quantified, selection of a high power, low-cost objective lens, our smartphone microscope has an imaging resolution of microns, with a working distance of 3 mm. It is therefore capable of imaging single cells and sub-cellular features, and retains usability for young children. The microscopes were designed in kit form and provided an interdisciplinary educational tool. By providing full lesson plans and support material, we developed a framework to explore optical design, microscope performance, engineering challenges on construction and real-world applications in life sciences, biological imaging, marine biology, art, and technology. A national online imaging competition framed EnLightenment ; with over 500 high quality images submitted of diverse content, spanning multiple disciplines. With examples of cellular and sub-cellular features clearly identifiable in some submissions, we show how young public can use these instruments for research-level imaging applications, and the potential of the instrument for citizen science programs.

Automated batch characterization of inkjet-printed elastomer lenses using a LEGO platform.

PubMed

Sung, Yu-Lung; Garan, Jacob; Nguyen, Hoang; Hu, Zhenyu; Shih, Wei-Chuan

2017-09-10

Small, self-adhesive, inkjet-printed elastomer lenses have enabled smartphone cameras to image and resolve microscopic objects. However, the performance of different lenses within a batch is affected by hard-to-control environmental variables. We present a cost-effective platform to perform automated batch characterization of 300 lens units simultaneously for quality inspection. The system was designed and configured with LEGO bricks, 3D printed parts, and a digital camera. The scheme presented here may become the basis of a high-throughput, in-line inspection tool for quality control purposes and can also be employed for optimization of the manufacturing process.

Development of and Clinical Experience with a Simple Device for Performing Intraoperative Fluorescein Fluorescence Cerebral Angiography: Technical Notes.

PubMed

Ichikawa, Tsuyoshi; Suzuki, Kyouichi; Watanabe, Yoichi; Sato, Taku; Sakuma, Jun; Saito, Kiyoshi

2016-01-01

To perform intraoperative fluorescence angiography (FAG) under a microscope without an integrated FAG function with reasonable cost and sufficient quality for evaluation, we made a small and easy to use device for fluorescein FAG (FAG filter). We investigated the practical use of this FAG filter during aneurysm surgery, revascularization surgery, and brain tumor surgery. The FAG filter consists of two types of filters: an excitatory filter and a barrier filter. The excitatory filter excludes all wavelengths except for blue light and the barrier filter passes long waves except for blue light. By adding this FAG filter to a microscope without an integrated FAG function, light from the microscope illuminating the surgical field becomes blue, which is blocked by the barrier filter. We put the FAG filter on the objective lens of the operating microscope correctly and fluorescein sodium was injected intravenously or intra-arterially. Fluorescence (green light) from vessels in the surgical field and the dyed tumor were clearly observed through the microscope and recorded by a memory device. This method was easy and could be performed in a short time (about 10 seconds). Blood flow of small vessels deep in the surgical field could be observed. Blood flow stagnation could be evaluated. However, images from this method were inferior to those obtained by currently commercially available microscopes with an integrated FAG function. In brain tumor surgery, a stained tumor on the brain surface could be observed using this method. FAG could be performed with a microscope without an integrated FAG function easily with only this FAG filter.

Development of and Clinical Experience with a Simple Device for Performing Intraoperative Fluorescein Fluorescence Cerebral Angiography: Technical Notes

PubMed Central

ICHIKAWA, Tsuyoshi; SUZUKI, Kyouichi; WATANABE, Yoichi; SATO, Taku; SAKUMA, Jun; SAITO, Kiyoshi

2016-01-01

To perform intraoperative fluorescence angiography (FAG) under a microscope without an integrated FAG function with reasonable cost and sufficient quality for evaluation, we made a small and easy to use device for fluorescein FAG (FAG filter). We investigated the practical use of this FAG filter during aneurysm surgery, revascularization surgery, and brain tumor surgery. The FAG filter consists of two types of filters: an excitatory filter and a barrier filter. The excitatory filter excludes all wavelengths except for blue light and the barrier filter passes long waves except for blue light. By adding this FAG filter to a microscope without an integrated FAG function, light from the microscope illuminating the surgical field becomes blue, which is blocked by the barrier filter. We put the FAG filter on the objective lens of the operating microscope correctly and fluorescein sodium was injected intravenously or intra-arterially. Fluorescence (green light) from vessels in the surgical field and the dyed tumor were clearly observed through the microscope and recorded by a memory device. This method was easy and could be performed in a short time (about 10 seconds). Blood flow of small vessels deep in the surgical field could be observed. Blood flow stagnation could be evaluated. However, images from this method were inferior to those obtained by currently commercially available microscopes with an integrated FAG function. In brain tumor surgery, a stained tumor on the brain surface could be observed using this method. FAG could be performed with a microscope without an integrated FAG function easily with only this FAG filter. PMID:26597335

Role of Aquaporin 0 in lens biomechanics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sindhu Kumari, S.; Gupta, Neha; Shiels, Alan

Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showedmore » the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to confer fiber cell shape, architecture and integrity. To our knowledge, this is the first report identifying the involvement of an aquaporin in lens biomechanics. Since accommodation is required in human lenses for proper focusing, alteration in the adhesion and/or water channel functions of AQP0 could contribute to presbyopia. - Highlights: • AQP0 aids in lens biomechanics. • AQP0 provides lens stiffness. • AQP0 is critical for lens transparency. • AQP0 could play a significant role in lens accommodation in human. • Alteration in the function(s) of lens AQP0 could lead to presbyopia.« less

Evolution of TUNEL-labeling in the rat lens after in vivo exposure to just above threshold dose UVB.

PubMed

Kronschläger, Martin; Yu, Zhaohua; Talebizadeh, Nooshin; Meyer, Linda M; Hallböök, Finn; Söderberg, Per G

2013-08-01

To quantitatively analyse the evolution of TUNEL-labeling, after in vivo exposure to UVB. Altogether, 16 Sprague Dawley rats were unilaterally exposed in vivo for 15 min to close to threshold dose, 5 kJ/m(2), of ultraviolet radiation in the 300 nm wavelength region. Animals were sacrificed in groups of 4 at 1, 5, 24 and 120 h after exposure. For each animal, both eye globes were removed and frozen. The frozen eye was cryo-sectioned in 10 µm thick midsagittal sections. From each globe, three midsagittal sections with at least five sections interval in between were mounted on a microscope slide. Sections were TUNEL-labeled and counter stained with DAPI. For quantification of apoptosis, a fluorescence microscope was used. In sections with a continuous epithelial cell surface, the number of lens epithelial cell nuclei and the number of TUNEL-positive epithelial cell nuclei was counted. The total number of TUNEL-positive epithelial cell nuclei for all three sections of one lens in relation to the total number of epithelial cell nuclei for all three sections of the same lens was compared between exposed and contralateral not exposed lens for each animal. The relative difference of the fraction of TUNEL-positive nuclei between exposed and contralateral not exposed lens increased gradually, peaked in the time interval 5-120 h after exposure, and then declined. Close to threshold dose of UVB induces TUNEL-labeling that peaks in the time window 5-120 h after exposure to UVB.

Septic implantation syndrome in dogs and cats: a distinct pattern of endophthalmitis with lenticular abscess.

PubMed

Bell, Cynthia M; Pot, Simon A; Dubielzig, Richard R

2013-05-01

To summarize the clinical and pathologic findings in a group of dogs and cats with progressive clinical ocular disease, which were diagnosed with suppurative endophthalmitis and lens capsule rupture. Twenty cats and forty-six dogs that underwent unilateral enucleation or evisceration for intractable uveitis and/or glaucoma. Biopsy submission requests and microscopic case material were evaluated for clinical and histological features, including history of ocular trauma, duration of ocular disease, pattern of inflammation, and the presence of intralenticular microorganisms. The median duration for cats and dogs was 6 and 5 weeks, respectively. A history of trauma was reported for four (20%) cats and 18 (39%) dogs. All confirmed cases of trauma-three in cats and 14 in dogs-were caused by a cat scratch. Microscopically, all cases had suppurative endophthalmitis centered on the lens, lens capsule rupture, cataract, and lenticular abscess. Infectious organisms were identified by Gram stain within the lens of 14 (70%) cats and 30 (65%) dogs. Gram-positive cocci were seen most commonly. Male cats were overrepresented as compared to females. There were no apparent gender, age or breed predilections in dogs. A unique pattern of slowly progressive or delayed-onset endophthalmitis with lens capsule rupture, lenticular abscess, and frequently intralenticular microorganisms is associated with traumatic penetration of the globe and lens capsule. The term Septic Implantation Syndrome (SIS) is favored in lieu of 'phacoclastic uveitis' to avoid confusion with phacolytic uveitis and to clearly implicate the role of intralenticular microorganisms in the pathogenesis. © 2012 American College of Veterinary Ophthalmologists.

Lens-free microscopy of cerebrospinal fluid for the laboratory diagnosis of meningitis

NASA Astrophysics Data System (ADS)

Delacroix, Robin; Morel, Sophie Nhu An; Hervé, Lionel; Bordy, Thomas; Blandin, Pierre; Dinten, Jean-Marc; Drancourt, Michel; Allier, Cédric

2018-02-01

The cytology of the cerebrospinal fluid is traditionally performed by an operator (physician, biologist) by means of a conventional light microscope. The operator visually counts the leukocytes (white blood cells) present in a sample of cerebrospinal fluid (10 μl). It is a tedious job and the result is operator-dependent. Here in order to circumvent the limitations of manual counting, we approach the question of numeration of erythrocytes and leukocytes for the cytological diagnosis of meningitis by means of lens-free microscopy. In a first step, a prospective counts of leukocytes was performed by five different operators using conventional optical microscopy. The visual counting yielded an overall 16.7% misclassification of 72 cerebrospinal fluid specimens in meningitis/non-meningitis categories using a 10 leukocyte/μL cut-off. In a second step, the lens-free microscopy algorithm was adapted step-by-step for counting cerebrospinal fluid cells and discriminating leukocytes from erythrocytes. The optimization of the automatic lens-free counting was based on the prospective analysis of 215 cerebrospinal fluid specimens. The optimized algorithm yielded a 100% sensitivity and a 86% specificity compared to confirmed diagnostics. In a third step, a blind lens-free microscopic analysis of 116 cerebrospinal fluid specimens, including six cases of microbiology confirmed infectious meningitis, yielded a 100% sensitivity and a 79% specificity. Adapted lens-free microscopy is thus emerging as an operator-independent technique for the rapid numeration of leukocytes and erythrocytes in cerebrospinal fluid. In particular, this technique is well suited to the rapid diagnosis of meningitis at point-of-care laboratories.

Lens-free computational imaging of capillary morphogenesis within three-dimensional substrates

NASA Astrophysics Data System (ADS)

Weidling, John; Isikman, Serhan O.; Greenbaum, Alon; Ozcan, Aydogan; Botvinick, Elliot

2012-12-01

Endothelial cells cultured in three-dimensional (3-D) extracellular matrices spontaneously form microvessels in response to soluble and matrix-bound factors. Such cultures are common for the study of angiogenesis and may find widespread use in drug discovery. Vascular networks are imaged over weeks to measure the distribution of vessel morphogenic parameters. Measurements require micron-scale spatial resolution, which for light microscopy comes at the cost of limited field-of-view (FOV) and shallow depth-of-focus (DOF). Small FOVs and DOFs necessitate lateral and axial mechanical scanning, thus limiting imaging throughput. We present a lens-free holographic on-chip microscopy technique to rapidly image microvessels within a Petri dish over a large volume without any mechanical scanning. This on-chip method uses partially coherent illumination and a CMOS sensor to record in-line holographic images of the sample. For digital reconstruction of the measured holograms, we implement a multiheight phase recovery method to obtain phase images of capillary morphogenesis over a large FOV (24 mm2) with ˜1.5 μm spatial resolution. On average, measured capillary length in our method was within approximately 2% of lengths measured using a 10× microscope objective. These results suggest lens-free on-chip imaging is a useful toolset for high-throughput monitoring and quantitative analysis of microvascular 3-D networks.

Optical alignment using a CGH and an autostigmatic microscope

NASA Astrophysics Data System (ADS)

Parks, Robert E.

2017-08-01

We show how custom computer generated holograms (CGH) are used along with an autostigmatic microscope (ASM) to align both optical and mechanical components relative to the CGH. The patterns in the CGHs define points and lines in space when interrogated with the focus of the ASM. Once the ASM is aligned to the CGH, an optical or mechanical component such as a lens, a well-polished ball or a cylinder can be aligned to the ASM in 3 or 4 degrees of freedom and thus to the CGH. In this case we show how a CGH is used to make a fixture for cementing a doublet lens without the need for a rotary table or a precision vertical stage.

From Animaculum to single molecules: 300 years of the light microscope.

PubMed

Wollman, Adam J M; Nudd, Richard; Hedlund, Erik G; Leake, Mark C

2015-04-01

Although not laying claim to being the inventor of the light microscope, Antonj van Leeuwenhoek (1632-1723) was arguably the first person to bring this new technological wonder of the age properly to the attention of natural scientists interested in the study of living things (people we might now term 'biologists'). He was a Dutch draper with no formal scientific training. From using magnifying glasses to observe threads in cloth, he went on to develop over 500 simple single lens microscopes (Baker & Leeuwenhoek 1739 Phil. Trans. 41, 503-519. (doi:10.1098/rstl.1739.0085)) which he used to observe many different biological samples. He communicated his finding to the Royal Society in a series of letters (Leeuwenhoek 1800 The select works of Antony Van Leeuwenhoek, containing his microscopical discoveries in many of the works of nature, vol. 1) including the one republished in this edition of Open Biology. Our review here begins with the work of van Leeuwenhoek before summarizing the key developments over the last ca 300 years, which has seen the light microscope evolve from a simple single lens device of van Leeuwenhoek's day into an instrument capable of observing the dynamics of single biological molecules inside living cells, and to tracking every cell nucleus in the development of whole embryos and plants.

van Leeuwenhoek microscopes-where are they now?

PubMed

Robertson, Lesley A

2015-05-01

When Antonie van Leeuwenhoek died, he left over 500 simple microscopes, aalkijkers (an adaption of his microscope to allow the examination of blood circulation in the tails of small eels) and lenses, yet now there are only 10 microscopes with a claim to being authentic, one possible aalkijker and six lenses. He made microscopes with more than one lens, and possibly three forms of the aalkijker. This paper attempts to establish exactly what he left and trace the fate of some of the others using the earliest possible documents and publications. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Miniaturized fiber-coupled confocal fluorescence microscope with an electrowetting variable focus lens using no moving parts

PubMed Central

Ozbay, Baris N.; Losacco, Justin T.; Cormack, Robert; Weir, Richard; Bright, Victor M.; Gopinath, Juliet T.; Restrepo, Diego; Gibson, Emily A.

2015-01-01

We report a miniature, lightweight fiber-coupled confocal fluorescence microscope that incorporates an electrowetting variable focus lens to provide axial scanning for full three-dimensional (3D) imaging. Lateral scanning is accomplished by coupling our device to a laser-scanning confocal microscope through a coherent imaging fiber-bundle. The optical components of the device are combined in a custom 3D-printed adapter with an assembled weight of <2 g that can be mounted onto the head of a mouse. Confocal sectioning provides an axial resolution of ~12 µm and an axial scan range of ~80 µm. The lateral field-of-view is 300 µm, and the lateral resolution is 1.8 µm. We determined these parameters by imaging fixed sections of mouse neuronal tissue labeled with green fluorescent protein (GFP) and fluorescent bead samples in agarose gel. To demonstrate viability for imaging intact tissue, we resolved multiple optical sections of ex vivo mouse olfactory nerve fibers expressing yellow fluorescent protein (YFP). PMID:26030555

Optimized computational imaging methods for small-target sensing in lens-free holographic microscopy

NASA Astrophysics Data System (ADS)

Xiong, Zhen; Engle, Isaiah; Garan, Jacob; Melzer, Jeffrey E.; McLeod, Euan

2018-02-01

Lens-free holographic microscopy is a promising diagnostic approach because it is cost-effective, compact, and suitable for point-of-care applications, while providing high resolution together with an ultra-large field-of-view. It has been applied to biomedical sensing, where larger targets like eukaryotic cells, bacteria, or viruses can be directly imaged without labels, and smaller targets like proteins or DNA strands can be detected via scattering labels like micro- or nano-spheres. Automated image processing routines can count objects and infer target concentrations. In these sensing applications, sensitivity and specificity are critically affected by image resolution and signal-to-noise ratio (SNR). Pixel super-resolution approaches have been shown to boost resolution and SNR by synthesizing a high-resolution image from multiple, partially redundant, low-resolution images. However, there are several computational methods that can be used to synthesize the high-resolution image, and previously, it has been unclear which methods work best for the particular case of small-particle sensing. Here, we quantify the SNR achieved in small-particle sensing using regularized gradient-descent optimization method, where the regularization is based on cardinal-neighbor differences, Bayer-pattern noise reduction, or sparsity in the image. In particular, we find that gradient-descent with sparsity-based regularization works best for small-particle sensing. These computational approaches were evaluated on images acquired using a lens-free microscope that we assembled from an off-the-shelf LED array and color image sensor. Compared to other lens-free imaging systems, our hardware integration, calibration, and sample preparation are particularly simple. We believe our results will help to enable the best performance in lens-free holographic sensing.

Light-sheet microscopy for everyone? Experience of building an OpenSPIM to study flatworm development.

PubMed

Girstmair, Johannes; Zakrzewski, Anne; Lapraz, François; Handberg-Thorsager, Mette; Tomancak, Pavel; Pitrone, Peter Gabriel; Simpson, Fraser; Telford, Maximilian J

2016-06-30

Selective plane illumination microscopy (SPIM a type of light-sheet microscopy) involves focusing a thin sheet of laser light through a specimen at right angles to the objective lens. As only the thin section of the specimen at the focal plane of the lens is illuminated, out of focus light is naturally absent and toxicity due to light (phototoxicity) is greatly reduced enabling longer term live imaging. OpenSPIM is an open access platform (Pitrone et al. 2013 and OpenSPIM.org) created to give new users step-by-step instructions on building a basic configuration of a SPIM microscope, which can in principle be adapted and upgraded to each laboratory's own requirements and budget. Here we describe our own experience with the process of designing, building, configuring and using an OpenSPIM for our research into the early development of the polyclad flatworm Maritigrella crozieri - a non-model animal. Our OpenSPIM builds on the standard design with the addition of two colour laser illumination for simultaneous detection of two probes/molecules and dual sided illumination, which provides more even signal intensity across a specimen. Our OpenSPIM provides high resolution 3d images and time lapse recordings, and we demonstrate the use of two colour lasers and the benefits of two color dual-sided imaging. We used our microscope to study the development of the embryo of the polyclad flatworm M. crozieri. The capabilities of our microscope are demonstrated by our ability to record the stereotypical spiral cleavage pattern of M. crozieri with high-speed multi-view time lapse imaging. 3D and 4D (3D + time) reconstruction of early development from these data is possible using image registration and deconvolution tools provided as part of the open source Fiji platform. We discuss our findings on the pros and cons of a self built microscope. We conclude that home-built microscopes, such as an OpenSPIM, together with the available open source software, such as MicroManager and Fiji, make SPIM accessible to anyone interested in having continuous access to their own light-sheet microscope. However, building an OpenSPIM is not without challenges and an open access microscope is a worthwhile, if significant, investment of time and money. Multi-view 4D microscopy is more challenging than we had expected. We hope that our experience gained during this project will help future OpenSPIM users with similar ambitions.

Microscope using an x-ray tube and a bubble compound refractive lens

NASA Astrophysics Data System (ADS)

Piestrup, M. A.; Gary, C. K.; Park, H.; Harris, J. L.; Cremer, J. T.; Pantell, R. H.; Dudchik, Y. I.; Kolchevsky, N. N.; Komarov, F. F.

2005-03-01

We present x-ray images of grid meshes and biological material obtained using an unfiltered x-ray tube and a compound refractive lens composed of microbubbles embedded in epoxy inside a glass capillary. Images obtained using this apparatus are compared with those using a synchrotron source and the same lens. We find that the field of view is larger than that obtained using the synchrotron source, whereas the contrast and resolution are reduced. Geometrical distortion around the edges of the field of view is also reduced. The experiments demonstrate the usefulness of the apparatus in a modest laboratory setting.

Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes

DOEpatents

Crewe, Albert V.

2000-01-01

Disclosed are lens apparatus in which a beam of charged particlesis brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscopeas the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.

Corneal edema and permanent blue discoloration of a silicone intraocular lens by methylene blue.

PubMed

Stevens, Scott; Werner, Liliana; Mamalis, Nick

2007-01-01

To report a silicone intraocular lens (IOL) stained blue by inadvertent intraoperative use of methylene blue instead of trypan blue and the results of experimental staining of various lens materials with different concentrations of the same dye. A "blue dye" was used to enhance visualization during capsulorhexis in a patient undergoing phacoemulsification with implantation of a three-piece silicone lens. Postoperatively, the patient presented with corneal edema and a discolored IOL. Various IOL materials were experimentally stained using methylene blue. Sixteen lenses (4 silicone, 4 hydrophobic acrylic, 4 hydrophilic acrylic, and 4 polymethylmethacrylate) were immersed in 0.5 mL of methylene blue at concentrations of 1%, 0.1%, 0.01%, and 0.001%. These lenses were grossly and microscopically evaluated for discoloration 6 and 24 hours after immersion. The corneal edema resolved within 1 month after the initial surgical procedure. After explantation, gross and microscopic analyses of the explanted silicone lens revealed that its surface and internal substance had been permanently stained blue. In the experimental study, all of the lenses except the polymethylmethacrylate lenses were permanently stained by methylene blue. The hydrophilic acrylic lenses showed the most intense blue staining in all dye concentrations. This is the first clinicopathological report of IOL discoloration due to intraocular use of methylene blue. This and other tissue dyes may be commonly found among surgical supplies in the operating room and due diligence is necessary to avoid mistaking these dyes for those commonly used during ocular surgery.

3D imaging of optically cleared tissue using a simplified CLARITY method and on-chip microscopy

PubMed Central

Zhang, Yibo; Shin, Yoonjung; Sung, Kevin; Yang, Sam; Chen, Harrison; Wang, Hongda; Teng, Da; Rivenson, Yair; Kulkarni, Rajan P.; Ozcan, Aydogan

2017-01-01

High-throughput sectioning and optical imaging of tissue samples using traditional immunohistochemical techniques can be costly and inaccessible in resource-limited areas. We demonstrate three-dimensional (3D) imaging and phenotyping in optically transparent tissue using lens-free holographic on-chip microscopy as a low-cost, simple, and high-throughput alternative to conventional approaches. The tissue sample is passively cleared using a simplified CLARITY method and stained using 3,3′-diaminobenzidine to target cells of interest, enabling bright-field optical imaging and 3D sectioning of thick samples. The lens-free computational microscope uses pixel super-resolution and multi-height phase recovery algorithms to digitally refocus throughout the cleared tissue and obtain a 3D stack of complex-valued images of the sample, containing both phase and amplitude information. We optimized the tissue-clearing and imaging system by finding the optimal illumination wavelength, tissue thickness, sample preparation parameters, and the number of heights of the lens-free image acquisition and implemented a sparsity-based denoising algorithm to maximize the imaging volume and minimize the amount of the acquired data while also preserving the contrast-to-noise ratio of the reconstructed images. As a proof of concept, we achieved 3D imaging of neurons in a 200-μm-thick cleared mouse brain tissue over a wide field of view of 20.5 mm2. The lens-free microscope also achieved more than an order-of-magnitude reduction in raw data compared to a conventional scanning optical microscope imaging the same sample volume. Being low cost, simple, high-throughput, and data-efficient, we believe that this CLARITY-enabled computational tissue imaging technique could find numerous applications in biomedical diagnosis and research in low-resource settings. PMID:28819645

Microspectroscopic imaging of solution plasma: How do its physical properties and chemical species evolve in atmospheric-pressure water vapor bubbles?

NASA Astrophysics Data System (ADS)

Yui, Hiroharu; Banno, Motohiro

2018-01-01

In this article, we review the development of scientific instruments for obtaining information on the evolution of physical properties and chemical species of solution plasma (SP). When a pulsed high voltage is applied between electrodes immersed in an aqueous solution, SP is formed in water vapor bubbles transiently generated in the solution under atmospheric pressure. To clarify how SP emerges in water vapor bubbles and is sustained in solutions, an instrument with micrometer spatial resolution and nanosecond temporal resolution is required. To meet these requirements, a microscopic system with a custom-made optical discharge cell was newly developed, where the working distance between the SP and the microscopic objective lens was minimized. A hollow electrode equipped in the discharge cell also enabled us to control the chemical composition in water vapor bubbles. To study the spatial and temporal evolutions of chemical species in micrometer and nano- to microsecond regions, a streak camera with a spectrometer and a CCD detector with a time-gated electronic device were combined with the microscope system. The developed instrument is expected to contribute to providing a new means of developing new schemes for chemical reactions and material syntheses.

Spectroscopic imaging of biomaterials and biological systems with FTIR microscopy or with quantum cascade lasers.

PubMed

Kimber, James A; Kazarian, Sergei G

2017-10-01

Spectroscopic imaging of biomaterials and biological systems has received increased interest within the last decade because of its potential to aid in the detection of disease using biomaterials/biopsy samples and to probe the states of live cells in a label-free manner. The factors behind this increased attention include the availability of improved infrared microscopes and systems that do not require the use of a synchrotron as a light source, as well as the decreasing costs of these systems. This article highlights the current technical challenges and future directions of mid-infrared spectroscopic imaging within this field. Specifically, these are improvements in spatial resolution and spectral quality through the use of novel added lenses and computational algorithms, as well as quantum cascade laser imaging systems, which offer advantages over traditional Fourier transform infrared systems with respect to the speed of acquisition and field of view. Overcoming these challenges will push forward spectroscopic imaging as a viable tool for disease diagnostics and medical research. Graphical abstract Absorbance images of a biopsy obtained using an FTIR imaging microscope with and without an added lens, and also using a QCL microscope with high-NA objective.

Lensfree super-resolution holographic microscopy using wetting films on a chip

NASA Astrophysics Data System (ADS)

Mudanyali, Onur; Bishara, Waheb; Ozcan, Aydogan

2011-08-01

We investigate the use of wetting films to significantly improve the imaging performance of lensfree pixel super-resolution on-chip microscopy, achieving < 1 μm spatial resolution over a large imaging area of ~24 mm2. Formation of an ultra-thin wetting film over the specimen effectively creates a micro-lens effect over each object, which significantly improves the signal-to-noise-ratio and therefore the resolution of our lensfree images. We validate the performance of this approach through lensfree on-chip imaging of various objects having fine morphological features (with dimensions of e.g., ≤0.5 μm) such as Escherichia coli (E. coli), human sperm, Giardia lamblia trophozoites, polystyrene micro beads as well as red blood cells. These results are especially important for the development of highly sensitive field-portable microscopic analysis tools for resource limited settings.

Three-dimensional fluorescent microscopy via simultaneous illumination and detection at multiple planes.

PubMed

Ma, Qian; Khademhosseinieh, Bahar; Huang, Eric; Qian, Haoliang; Bakowski, Malina A; Troemel, Emily R; Liu, Zhaowei

2016-08-16

The conventional optical microscope is an inherently two-dimensional (2D) imaging tool. The objective lens, eyepiece and image sensor are all designed to capture light emitted from a 2D 'object plane'. Existing technologies, such as confocal or light sheet fluorescence microscopy have to utilize mechanical scanning, a time-multiplexing process, to capture a 3D image. In this paper, we present a 3D optical microscopy method based upon simultaneously illuminating and detecting multiple focal planes. This is implemented by adding two diffractive optical elements to modify the illumination and detection optics. We demonstrate that the image quality of this technique is comparable to conventional light sheet fluorescent microscopy with the advantage of the simultaneous imaging of multiple axial planes and reduced number of scans required to image the whole sample volume.

Measurement of anchoring coefficient of homeotropically aligned nematic liquid crystal using a polarizing optical microscope in reflective mode

NASA Astrophysics Data System (ADS)

Baek, Sang-In; Kim, Sung-Jo; Kim, Jong-Hyun

2015-09-01

Although the homeotropic alignment of liquid crystals is widely used in LCD TVs, no easy method exists to measure its anchoring coefficient. In this study, we propose an easy and convenient measurement technique in which a polarizing optical microscope is used in the reflective mode with an objective lens having a low depth of focus. All measurements focus on the reflection of light near the interface between the liquid crystal and alignment layer. The change in the reflected light is measured by applying an electric field. We model the response of the director of the liquid crystal to the electric field and, thus, the change in reflectance. By adjusting the extrapolation length in the calculation, we match the experimental and calculated results and obtain the anchoring coefficient. In our experiment, the extrapolation lengths were 0.31 ± 0.04 μm, 0.32 ± 0.08 μm, and 0.23 ± 0.05 μm for lecithin, AL-64168, and SE-5662, respectively.

MEMS-based handheld confocal microscope for in-vivo skin imaging

PubMed Central

Arrasmith, Christopher L.; Dickensheets, David L.; Mahadevan-Jansen, Anita

2010-01-01

This paper describes a handheld laser scanning confocal microscope for skin microscopy. Beam scanning is accomplished with an electromagnetic MEMS bi-axial micromirror developed for pico projector applications, providing 800x600 (SVGA) resolution at 56 frames per second. The design uses commercial objective lenses with an optional hemisphere front lens, operating with a range of numerical aperture from NA=0.35 to NA=1.1 and corresponding diagonal field of view ranging from 653 μm to 216 μm. Using NA=1.1 and a laser wavelength of 830 nm we measured the axial response to be 1.14 μm full width at half maximum, with a corresponding 10%-90% lateral edge response of 0.39 μm. Image examples showing both epidermal and dermal features including capillary blood flow are provided. These images represent the highest resolution and frame rate yet achieved for tissue imaging with a MEMS bi-axial scan mirror. PMID:20389391

OPTiM: Optical projection tomography integrated microscope using open-source hardware and software

PubMed Central

Andrews, Natalie; Davis, Samuel; Bugeon, Laurence; Dallman, Margaret D.; McGinty, James

2017-01-01

We describe the implementation of an OPT plate to perform optical projection tomography (OPT) on a commercial wide-field inverted microscope, using our open-source hardware and software. The OPT plate includes a tilt adjustment for alignment and a stepper motor for sample rotation as required by standard projection tomography. Depending on magnification requirements, three methods of performing OPT are detailed using this adaptor plate: a conventional direct OPT method requiring only the addition of a limiting aperture behind the objective lens; an external optical-relay method allowing conventional OPT to be performed at magnifications >4x; a remote focal scanning and region-of-interest method for improved spatial resolution OPT (up to ~1.6 μm). All three methods use the microscope’s existing incoherent light source (i.e. arc-lamp) and all of its inherent functionality is maintained for day-to-day use. OPT acquisitions are performed on in vivo zebrafish embryos to demonstrate the implementations’ viability. PMID:28700724

Longitudinal changes in Langerhans cell density of the cornea and conjunctiva in contact lens-induced dry eye.

PubMed

Alzahrani, Yahya; Colorado, Luisa H; Pritchard, Nicola; Efron, Nathan

2017-01-01

The aim was to determine longitudinal changes in Langerhans cell density (LCD) in the human cornea and conjunctiva during asymptomatic and symptomatic contact lens wear. Twenty-five participants with contact lens-induced dry eye (CLIDE) and 35 without CLIDE (NO-CLIDE), diagnosed using a range of symptom questionnaires and objective tests (tear film break up, cotton thread tear test and corneal staining) were enrolled. The central cornea and nasal bulbar conjunctiva were examined using a Heidelberg laser scanning confocal microscope at baseline and following one, four and 24 weeks wear of daily disposable hydrogel contact lenses. Twenty-three non-contact lens-wearing controls were also examined. Langerhans cells were counted manually from randomly selected images. In the cornea, mean and standard error of the mean LCD was greater after one week of lens wear in CLIDE (55 ± 7 cells/mm 2 ) versus NO-CLIDE (43 ± 4 cells/mm 2 ) (p = 0.041) and controls (27 ± 4 cells/mm 2 ) (p < 0.001). LCD was also greater in NO-CLIDE versus controls (p = 0.010). At week 4, LCD was greater in CLIDE (41 ± 6 cells/mm 2 ) versus controls (27 ± 4 cells/mm 2 ) (p = 0.004). There were no other significant differences between groups at weeks four or 24. In the conjunctiva, LCD was greater after one week of lens wear in CLIDE (17 ± 1 cells/mm 2 ) (p = 0.003) and NO-CLIDE (17 ± 3 cells/mm 2 ) (p = 0.001) versus controls (7 ± 1 cells/mm 2 ). There were no significant differences between groups at weeks four or 24. The initial transient increase in corneal and conjunctival LCD in CLIDE (versus NO-CLIDE) suggests an inflammatory component in the aetiology of this condition. © 2016 Optometry Australia.

Objective lens

NASA Technical Reports Server (NTRS)

Olczak, Eugene G. (Inventor)

2011-01-01

An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

Office-Based Diagnosis of Demodex Using Smartphone.

PubMed

Kaya, Abdullah; Gürdal, Canan

2018-06-25

Demodex is an important pathogen in ophthalmology. It is believed to cause a variety of eyelid and eyelash diseases. Currently, light microscopes are being used for imaging demodex. However, microscopes are not available everywhere. Also, it is not cost-effective to perform light microscopy in every case. In this case, we demonstrate a new method: imaging demodex using cell phone. A 90-diopter noncontact double aspheric lens was attached to the posterior camera of the smartphone with clear tape. An eyelash of a patient with blepharitis was removed. A video was taken using smartphone. There was a moving demodex parasite in the root of the eyelash. A clear video image could be taken using the smartphone. A smartphone and a 90-diopter lens are adequate for the imaging and diagnosis of demodex.

Rapid fabrication of micro-nanometric tapered fiber lens and characterization by a novel scanning optical microscope with submicron resolution.

PubMed

Zheng, Shouguo; Zeng, Xinhua; Luo, Wei; Jradi, Safi; Plain, Jérôme; Li, Miao; Renaud-Goud, Philippe; Deturche, Régis; Wang, Zengfu; Kou, Jieting; Bachelot, Renaud; Royer, Pascal

2013-01-14

In numerous applications of optical scanning microscopy, a reference tapered fiber lens with high symmetry at sub-wavelength scale remains a challenge. Here, we demonstrate the ability to manufacture it with a wide range of geometry control, either for the length from several hundred nanometers to several hundred microns, or for the curvature radius from several tens of nanometers to several microns on the endface of a single mode fiber. On this basis, a scanning optical microscope has been developed, which allows for fast characterization of various sub-wavelength tapered fiber lenses. Focal position and depth of microlenses with different geometries have been determined to be ranged from several hundreds of nanometers to several microns. FDTD calculations are consistent with experimental results.

Repertoire of free-living protozoa in contact lens solutions.

PubMed

Bouchoucha, Ibtissem; Aziz, Aurore; Hoffart, Louis; Drancourt, Michel

2016-10-29

The repertoire of free-living protozoa in contact lens solutions is poorly known despite the fact that such protozoa may act as direct pathogens and may harbor intra-cellular pathogens. Between 2009 and 2014, the contact lens solutions collected from patients presenting at our Ophthalmology Department for clinically suspected keratitis, were cultured on non-nutrient agar examined by microscope for the presence of free-living protozoa. All protozoa were identified by 18S rRNA gene sequencing. A total of 20 of 233 (8.6 %) contact lens solution specimens collected from 16 patients were cultured. Acanthamoeba amoeba in 16 solutions (80 %) collected from 12 patients and Colpoda steini, Cercozoa sp., Protostelium sp. and a eukaryotic more closely related to Vermamoeba sp., were each isolated in one solution. Cercozoa sp., Colpoda sp., Protostelium sp. and Vermamoeba sp. are reported for the first time as contaminating contact lens solutions. The repertoire of protozoa in contact lens solutions is larger than previously known.

A simple but precise method for quantitative measurement of the quality of the laser focus in a scanning optical microscope

PubMed Central

MACRAE, K.; TRAVIS, C.; AMOR, R.; NORRIS, G.; WILSON, S.H.; OPPO, G.‐L.; MCCONNELL, G.

2015-01-01

Summary We report a method for characterizing the focussing laser beam exiting the objective in a laser scanning microscope. This method provides the size of the optical focus, the divergence of the beam, the ellipticity and the astigmatism. We use a microscopic‐scale knife edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide, and a light‐collecting optical fibre and photodiode underneath the specimen. By scanning the laser spot from a reflective to a transmitting part of the grid, a beam profile in the form of an error function can be obtained and by repeating this with the knife edge at different axial positions relative to the beam waist, the divergence and astigmatism of the postobjective laser beam can be obtained. The measured divergence can be used to quantify how much of the full numerical aperture of the lens is used in practice. We present data of the beam radius, beam divergence, ellipticity and astigmatism obtained with low (0.15, 0.7) and high (1.3) numerical aperture lenses and lasers commonly used in confocal and multiphoton laser scanning microscopy. Our knife‐edge method has several advantages over alternative knife‐edge methods used in microscopy including that the knife edge is easy to prepare, that the beam can be characterized also directly under a cover slip, as necessary to reduce spherical aberrations for objectives designed to be used with a cover slip, and it is suitable for use with commercial laser scanning microscopes where access to the laser beam can be limited. PMID:25864964

Dielectric Optical-Controllable Magnifying Lens by Nonlinear Negative Refraction

PubMed Central

Cao, Jianjun; Shang, Ce; Zheng, Yuanlin; Feng, Yaming; Chen, Xianfeng; Liang, Xiaogan; Wan, Wenjie

2015-01-01

A simple optical lens plays an important role for exploring the microscopic world in science and technology by refracting light with tailored spatially varying refractive indices. Recent advancements in nanotechnology enable novel lenses, such as, superlens and hyperlens, with sub-wavelength resolution capabilities by specially designed materials’ refractive indices with meta-materials and transformation optics. However, these artificially nano- or micro-engineered lenses usually suffer high losses from metals and are highly demanding in fabrication. Here, we experimentally demonstrate, for the first time, a nonlinear dielectric magnifying lens using negative refraction by degenerate four-wave mixing in a plano-concave glass slide, obtaining magnified images. Moreover, we transform a nonlinear flat lens into a magnifying lens by introducing transformation optics into the nonlinear regime, achieving an all-optical controllable lensing effect through nonlinear wave mixing, which may have many potential applications in microscopy and imaging science. PMID:26149952

From Animaculum to single molecules: 300 years of the light microscope

PubMed Central

Wollman, Adam J. M.; Nudd, Richard; Hedlund, Erik G.; Leake, Mark C.

2015-01-01

Although not laying claim to being the inventor of the light microscope, Antonj van Leeuwenhoek (1632–1723) was arguably the first person to bring this new technological wonder of the age properly to the attention of natural scientists interested in the study of living things (people we might now term ‘biologists’). He was a Dutch draper with no formal scientific training. From using magnifying glasses to observe threads in cloth, he went on to develop over 500 simple single lens microscopes (Baker & Leeuwenhoek 1739 Phil. Trans. 41, 503–519. (doi:10.1098/rstl.1739.0085)) which he used to observe many different biological samples. He communicated his finding to the Royal Society in a series of letters (Leeuwenhoek 1800 The select works of Antony Van Leeuwenhoek, containing his microscopical discoveries in many of the works of nature, vol. 1) including the one republished in this edition of Open Biology. Our review here begins with the work of van Leeuwenhoek before summarizing the key developments over the last ca 300 years, which has seen the light microscope evolve from a simple single lens device of van Leeuwenhoek's day into an instrument capable of observing the dynamics of single biological molecules inside living cells, and to tracking every cell nucleus in the development of whole embryos and plants. PMID:25924631

Selective plane illumination microscopy (SPIM) with time-domain fluorescence lifetime imaging microscopy (FLIM) for volumetric measurement of cleared mouse brain samples

NASA Astrophysics Data System (ADS)

Funane, Tsukasa; Hou, Steven S.; Zoltowska, Katarzyna Marta; van Veluw, Susanne J.; Berezovska, Oksana; Kumar, Anand T. N.; Bacskai, Brian J.

2018-05-01

We have developed an imaging technique which combines selective plane illumination microscopy with time-domain fluorescence lifetime imaging microscopy (SPIM-FLIM) for three-dimensional volumetric imaging of cleared mouse brains with micro- to mesoscopic resolution. The main features of the microscope include a wavelength-adjustable pulsed laser source (Ti:sapphire) (near-infrared) laser, a BiBO frequency-doubling photonic crystal, a liquid chamber, an electrically focus-tunable lens, a cuvette based sample holder, and an air (dry) objective lens. The performance of the system was evaluated with a lifetime reference dye and micro-bead phantom measurements. Intensity and lifetime maps of three-dimensional human embryonic kidney (HEK) cell culture samples and cleared mouse brain samples expressing green fluorescent protein (GFP) (donor only) and green and red fluorescent protein [positive Förster (fluorescence) resonance energy transfer] were acquired. The results show that the SPIM-FLIM system can be used for sample sizes ranging from single cells to whole mouse organs and can serve as a powerful tool for medical and biological research.

EnLightenment: High resolution smartphone microscopy as an educational and public engagement platform

PubMed Central

Wicks, Laura C.; Cairns, Gemma S.; Melnyk, Jacob; Bryce, Scott; Duncan, Rory R.; Dalgarno, Paul A.

2018-01-01

We developed a simple, cost-effective smartphone microscopy platform for use in educational and public engagement programs. We demonstrated its effectiveness, and potential for citizen science through a national imaging initiative, EnLightenment. The cost effectiveness of the instrument allowed for the program to deliver over 500 microscopes to more than 100 secondary schools throughout Scotland, targeting 1000’s of 12-14 year olds. Through careful, quantified, selection of a high power, low-cost objective lens, our smartphone microscope has an imaging resolution of microns, with a working distance of 3 mm. It is therefore capable of imaging single cells and sub-cellular features, and retains usability for young children. The microscopes were designed in kit form and provided an interdisciplinary educational tool. By providing full lesson plans and support material, we developed a framework to explore optical design, microscope performance, engineering challenges on construction and real-world applications in life sciences, biological imaging, marine biology, art, and technology. A national online imaging competition framed EnLightenment ; with over 500 high quality images submitted of diverse content, spanning multiple disciplines. With examples of cellular and sub-cellular features clearly identifiable in some submissions, we show how young public can use these instruments for research-level imaging applications, and the potential of the instrument for citizen science programs. PMID:29623296

Delayed progression of diabetic cataractogenesis and retinopathy by Litchi chinensis in STZ-induced diabetic rats.

PubMed

Kilari, Eswar Kumar; Putta, Swathi

2017-03-01

The study was carried out to evaluate the effect of the aqueous fruit pericarp extract of Litchi chinensis (APLC) on parameters which leads to diabetic cataractogenesis and retinopathy in the streptozotocin-induced diabetic rats. The objective of the study is to evaluate the APLC for in vivo antioxidant activity and its role in inhibiting the polyol pathway and formation of advanced glycation end products (AGEs). The diabetic animals were treated with L. chinensis for a period of 12 weeks. At the end of 12 weeks, the animals were killed and the biochemical pathways involved in the pathogenesis of cataract such as oxidative stress by protein content, superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and polyolpathway by aldose reductase (AR) in lens homogenates, alterations in protein carbonyl content (PCO) and AGEs in both serum and lens the APLC-treated diabetic rats were compared against diabetic control rats. Cataract progression due to hyperglycemia was monitored by slit lamp bio microscope and classified into four stages. Fundoscope test and retinal histopathology were done for assessing retinopathy. Statistically significant reduction in glucose, and elevation of protein content, SOD, CAT, and GSH levels and decreased levels of AR and PCO in lens homogenate and significant reduction in AGEs serum and lens homogenate were observed. Slit lamp examination, fundoscope, and histopathology showed improvement in retinal changes in APLC-treated rats compared to diabetic control animals. The treatment with APLC found to delay the progression of diabetic cataractogenesis and retinopathy, which might be due to its antioxidant activity, because of the presence of active phytochemicals in APLC.

Microscope and method of use

DOEpatents

Bongianni, Wayne L.

1984-01-01

A method and apparatus for electronically focusing and electronically scanning microscopic specimens are given. In the invention, visual images of even moving, living, opaque specimens can be acoustically obtained and viewed with virtually no time needed for processing (i.e., real time processing is used). And planar samples are not required. The specimens (if planar) need not be moved during scanning, although it will be desirable and possible to move or rotate nonplanar specimens (e.g., laser fusion targets) against the lens of the apparatus. No coupling fluid is needed, so specimens need not be wetted. A phase acoustic microscope is also made from the basic microscope components together with electronic mixers.

Microscope and method of use

DOEpatents

Bongianni, W.L.

1984-04-17

A method and apparatus for electronically focusing and electronically scanning microscopic specimens are given. In the invention, visual images of even moving, living, opaque specimens can be acoustically obtained and viewed with virtually no time needed for processing (i.e., real time processing is used). And planar samples are not required. The specimens (if planar) need not be moved during scanning, although it will be desirable and possible to move or rotate nonplanar specimens (e.g., laser fusion targets) against the lens of the apparatus. No coupling fluid is needed, so specimens need not be wetted. A phase acoustic microscope is also made from the basic microscope components together with electronic mixers. 7 figs.

Miniature injection-molded optics for fiber-optic, in vivo confocal microscopy

NASA Astrophysics Data System (ADS)

Chidley, Matthew D.; Liang, Chen; Descour, Michael R.; Sung, Kung-Bin; Richards-Kortum, Rebecca R.; Gillenwater, Ann

2002-12-01

In collaboration with the Department of Biomedical Engineering at the University of Texas at Austin and the UT MD Anderson Cancer Center, a laser scanning fiber confocal reflectance microscope (FCRM) system has been designed and tested for in vivo detection of cervical and oral pre-cancers. This system along with specially developed diagnosis algorithms and techniques can achieve an unprecedented specificity and sensitivity for the diagnosis of pre-cancers in epithelial tissue. The FCRM imaging system consists of an NdYAG laser (1064 nm), scanning mirrors/optics, precision pinhole, detector, and an endoscopic probe (the objective). The objective is connected to the rest of the imaging system via a fiber bundle. The fiber bundle allows the rest of the system to be remotely positioned in a convenient location. Only the objective comes into contact with the patient. It is our intent that inexpensive mass-produced disposable endoscopic probes would be produced for large clinical trials. This paper touches on the general design process of developing a miniature, high numerical aperture, injection-molded (IM) objective. These IM optical designs are evaluated and modified based on manufacturing and application constraints. Based on these driving criteria, one specific optical design was chosen and a detailed tolerance analysis was conducted. The tolerance analysis was custom built to create a realistic statistical analysis for integrated IM lens elements that can be stacked one on top of another using micro-spheres resting in tiny circular grooves. These configurations allow each lens element to be rotated and possibly help compensate for predicted manufacturing errors. This research was supported by a grant from the National Institutes of Health (RO1 CA82880). Special thanks go to Applied Image Group/Optics for the numerous fabrication meetings concerning the miniature IM objective.

Ultrathin zoom telescopic objective.

PubMed

Li, Lei; Wang, Di; Liu, Chao; Wang, Qiong-Hua

2016-08-08

We report an ultrathin zoom telescopic objective that can achieve continuous zoom change and has reduced compact volume. The objective consists of an annular folded lens and three electrowetting liquid lenses. The annular folded lens undertakes the main part of the focal power of the lens system. Due to a multiple-fold design, the optical path is folded in a lens with the thickness of ~1.98mm. The electrowetting liquid lenses constitute a zoom part. Based on the proposed objective, an ultrathin zoom telescopic camera is demonstrated. We analyze the properties of the proposed objective. The aperture of the proposed objective is ~15mm. The total length of the system is ~18mm with a tunable focal length ~48mm to ~65mm. Compared with the conventional zoom telescopic objective, the total length has been largely reduced.

Full-field OCT: applications in ophthalmology

NASA Astrophysics Data System (ADS)

Grieve, Kate; Dubois, Arnaud; Paques, Michel; Le Gargasson, Jean-Francois; Boccara, Albert C.

2005-04-01

We present images of ocular tissues obtained using ultrahigh resolution full-field OCT. The experimental setup is based on the Linnik interferometer, illuminated by a tungsten halogen lamp. En face tomographic images are obtained in real-time without scanning by computing the difference of two phase-opposed interferometric images recorded by a high-resolution CCD camera. A spatial resolution of 0.7 μm × 0.9 μm (axial × transverse) is achieved thanks to the short source coherence length and the use of high numerical aperture microscope objectives. A detection sensitivity of 90 dB is obtained by means of image averaging and pixel binning. Whole unfixed eyes and unstained tissue samples (cornea, lens, retina, choroid and sclera) of ex vivo rat, mouse, rabbit and porcine ocular tissues were examined. The unprecedented resolution of our instrument allows cellular-level resolution in the cornea and retina, and visualization of individual fibers in the lens. Transcorneal lens imaging was possible in all animals, and in albino animals, transscleral retinal imaging was achieved. We also introduce our rapid acquisition full-field optical coherence tomography system designed to accommodate in vivo ophthalmologic imaging. The variations on the original system technology include the introduction of a xenon arc lamp as source, and rapid image acquisition performed by a high-speed CMOS camera, reducing acquisition time to 5 ms per frame.

Terahertz Microscope

DTIC Science & Technology

2010-05-01

at the Brewster angle . The area of the elliptical laser spot on the semiconductor is approximately 0.5 mm2, the average optical power is about 50 mW...approximately above 100 THz, with quantum transition as the dominating physics and lens and mirror as the guiding elements for optics. The science and...waveguides are tested with a gas laser and a pyroelectric detector. A CW THz beam at 1.62 THz is collimated from the gas laser and focused by a lens

Objective detection of apoptosis in rat renal tissue sections using light microscopy and free image analysis software with subsequent machine learning: Detection of apoptosis in renal tissue.

PubMed

Macedo, Nayana Damiani; Buzin, Aline Rodrigues; de Araujo, Isabela Bastos Binotti Abreu; Nogueira, Breno Valentim; de Andrade, Tadeu Uggere; Endringer, Denise Coutinho; Lenz, Dominik

2017-02-01

The current study proposes an automated machine learning approach for the quantification of cells in cell death pathways according to DNA fragmentation. A total of 17 images of kidney histological slide samples from male Wistar rats were used. The slides were photographed using an Axio Zeiss Vert.A1 microscope with a 40x objective lens coupled with an Axio Cam MRC Zeiss camera and Zen 2012 software. The images were analyzed using CellProfiler (version 2.1.1) and CellProfiler Analyst open-source software. Out of the 10,378 objects, 4970 (47,9%) were identified as TUNEL positive, and 5408 (52,1%) were identified as TUNEL negative. On average, the sensitivity and specificity values of the machine learning approach were 0.80 and 0.77, respectively. Image cytometry provides a quantitative analytical alternative to the more traditional qualitative methods more commonly used in studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Source brightness and useful beam current of carbon nanotubes and other very small emitters

NASA Astrophysics Data System (ADS)

Kruit, P.; Bezuijen, M.; Barth, J. E.

2006-01-01

The potential application of carbon nanotubes as electron sources in electron microscopes is analyzed. The resolution and probe current that can be obtained from a carbon nanotube emitter in a low-voltage scanning electron microscope are calculated and compared to the state of the art using Schottky electron sources. Many analytical equations for probe-size versus probe-current relations in different parameter regimes are obtained. It is shown that for most carbon nanotube emitters, the gun lens aberrations are larger than the emitters' virtual source size and thus restrict the microscope's performance. The result is that the advantages of the higher brightness of nanotube emitters are limited unless the angular emission current is increased over present day values or the gun lens aberrations are decreased. For some nanotubes with a closed cap, it is known that the emitted electron beam is coherent over the full emission cone. We argue that for such emitters the parameter ``brightness'' becomes meaningless. The influence of phase variations in the electron wave front emitted from such a nanotube emitter on the focusing of the electron beam is analyzed.

Energy-filtered real- and k-space secondary and energy-loss electron imaging with Dual Emission Electron spectro-Microscope: Cs/Mo(110).

PubMed

Grzelakowski, Krzysztof P

2016-05-01

Since its introduction the importance of complementary k||-space (LEED) and real space (LEEM) information in the investigation of surface science phenomena has been widely demonstrated over the last five decades. In this paper we report the application of a novel kind of electron spectromicroscope Dual Emission Electron spectroMicroscope (DEEM) with two independent electron optical channels for reciprocal and real space quasi-simultaneous imaging in investigation of a Cs covered Mo(110) single crystal by using the 800eV electron beam from an "in-lens" electron gun system developed for the sample illumination. With the DEEM spectromicroscope it is possible to observe dynamic, irreversible processes at surfaces in the energy-filtered real space and in the corresponding energy-filtered kǁ-space quasi-simultaneously in two independent imaging columns. The novel concept of the high energy electron beam sample illumination in the cathode lens based microscopes allows chemically selective imaging and analysis under laboratory conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

Camera, Hand Lens, and Microscope Probe (CHAMP): An Instrument Proposed for the 2009 MSL Rover Mission

NASA Technical Reports Server (NTRS)

Mungas, Greg S.; Beegle, Luther W.; Boynton, John E.; Lee, Pascal; Shidemantle, Ritch; Fisher, Ted

2004-01-01

The Camera, Hand Lens, and Microscope Probe (CHAMP) will allow examination of martian surface features and materials (terrain, rocks, soils, samples) on spatial scales ranging from kilometers to micrometers, thus enabling both microscopy and context imaging with high operational flexibility. CHAMP is designed to allow the detailed and quantitative investigation of a wide range of geologic features and processes on Mars, leading to a better quantitative understanding of the evolution of the martian surface environment through time. In particular, CHAMP will provide key data that will help understand the local region explored by Mars Surface Laboratory (MSL) as a potential habitat for life. CHAMP will also support other anticipated MSL investigations, in particular by helping identify and select the highest priority targets for sample collection and analysis by the MSL's analytical suite.

Reflection of a polarized light cone

NASA Astrophysics Data System (ADS)

Brody, Jed; Weiss, Daniel; Berland, Keith

2013-01-01

We introduce a visually appealing experimental demonstration of Fresnel reflection. In this simple optical experiment, a polarized light beam travels through a high numerical-aperture microscope objective, reflects off a glass slide, and travels back through the same objective lens. The return beam is sampled with a polarizing beam splitter and produces a surprising geometric pattern on an observation screen. Understanding the origin of this pattern requires careful attention to geometry and an understanding of the Fresnel coefficients for S and P polarized light. We demonstrate that in addition to a relatively simple experimental implementation, the shape of the observed pattern can be computed both analytically and by using optical modeling software. The experience of working through complex mathematical computations and demonstrating their agreement with a surprising experimental observation makes this a highly educational experiment for undergraduate optics or advanced-lab courses. It also provides a straightforward yet non-trivial system for teaching students how to use optical modeling software.

Integrated Micro-Optics for Microfluidic Detection.

PubMed

Kazama, Yuto; Hibara, Akihide

2016-01-01

A method of embedding micro-optics into a microfluidic device was proposed and demonstrated. First, the usefulness of embedded right-angle prisms was demonstrated in microscope observation. Lateral-view microscopic observation of an aqueous dye flow in a 100-μm-sized microchannel was demonstrated. Then, the embedded right-angle prisms were utilized for multi-beam laser spectroscopy. Here, crossed-beam thermal lens detection of a liquid sample was applied to glucose detection.

What Brown saw and you can too

NASA Astrophysics Data System (ADS)

Pearle, Philip; Collett, Brian; Bart, Kenneth; Bilderback, David; Newman, Dara; Samuels, Scott

2010-12-01

A discussion of Robert Brown's original observations of particles ejected by pollen of the plant Clarkia pulchella undergoing what is now called Brownian motion is given. We consider the nature of those particles and how he misinterpreted the Airy disk of the smallest particles to be universal organic building blocks. Relevant qualitative and quantitative investigations with a modern microscope and with a "homemade" single lens microscope similar to Brown's are presented.

Structured illumination 3D microscopy using adaptive lenses and multimode fibers

NASA Astrophysics Data System (ADS)

Czarske, Jürgen; Philipp, Katrin; Koukourakis, Nektarios

2017-06-01

Microscopic techniques with high spatial and temporal resolution are required for in vivo studying biological cells and tissues. Adaptive lenses exhibit strong potential for fast motion-free axial scanning. However, they also lead to a degradation of the achievable resolution because of aberrations. This hurdle can be overcome by digital optical technologies. We present a novel High-and-Low-frequency (HiLo) 3D-microscope using structured illumination and an adaptive lens. Uniform illumination is used to obtain optical sectioning for the high-frequency (Hi) components of the image, and nonuniform illumination is needed to obtain optical sectioning for the low-frequency (Lo) components of the image. Nonuniform illumination is provided by a multimode fiber. It ensures robustness against optical aberrations of the adaptive lens. The depth-of-field of our microscope can be adjusted a-posteriori by computational optics. It enables to create flexible scans, which compensate for irregular axial measurement positions. The adaptive HiLo 3D-microscope provides an axial scanning range of 1 mm with an axial resolution of about 4 microns and sub-micron lateral resolution over the full scanning range. In result, volumetric measurements with high temporal and spatial resolution are provided. Demonstration measurements of zebrafish embryos with reporter gene-driven fluorescence in the thyroid gland are presented.

Development of a Whole Slide Imaging System on Smartphones and Evaluation With Frozen Section Samples

PubMed Central

Jiang, Liren

2017-01-01

Background The aim was to develop scalable Whole Slide Imaging (sWSI), a WSI system based on mainstream smartphones coupled with regular optical microscopes. This ultra-low-cost solution should offer diagnostic-ready imaging quality on par with standalone scanners, supporting both oil and dry objective lenses of different magnifications, and reasonably high throughput. These performance metrics should be evaluated by expert pathologists and match those of high-end scanners. Objective The aim was to develop scalable Whole Slide Imaging (sWSI), a whole slide imaging system based on smartphones coupled with optical microscopes. This ultra-low-cost solution should offer diagnostic-ready imaging quality on par with standalone scanners, supporting both oil and dry object lens of different magnification. All performance metrics should be evaluated by expert pathologists and match those of high-end scanners. Methods In the sWSI design, the digitization process is split asynchronously between light-weight clients on smartphones and powerful cloud servers. The client apps automatically capture FoVs at up to 12-megapixel resolution and process them in real-time to track the operation of users, then give instant feedback of guidance. The servers first restitch each pair of FoVs, then automatically correct the unknown nonlinear distortion introduced by the lens of the smartphone on the fly, based on pair-wise stitching, before finally combining all FoVs into one gigapixel VS for each scan. These VSs can be viewed using Internet browsers anywhere. In the evaluation experiment, 100 frozen section slides from patients randomly selected among in-patients of the participating hospital were scanned by both a high-end Leica scanner and sWSI. All VSs were examined by senior pathologists whose diagnoses were compared against those made using optical microscopy as ground truth to evaluate the image quality. Results The sWSI system is developed for both Android and iPhone smartphones and is currently being offered to the public. The image quality is reliable and throughput is approximately 1 FoV per second, yielding a 15-by-15 mm slide under 20X object lens in approximately 30-35 minutes, with little training required for the operator. The expected cost for setup is approximately US $100 and scanning each slide costs between US $1 and $10, making sWSI highly cost-effective for infrequent or low-throughput usage. In the clinical evaluation of sample-wise diagnostic reliability, average accuracy scores achieved by sWSI-scan-based diagnoses were as follows: 0.78 for breast, 0.88 for uterine corpus, 0.68 for thyroid, and 0.50 for lung samples. The respective low-sensitivity rates were 0.05, 0.05, 0.13, and 0.25 while the respective low-specificity rates were 0.18, 0.08, 0.20, and 0.25. The participating pathologists agreed that the overall quality of sWSI was generally on par with that produced by high-end scanners, and did not affect diagnosis in most cases. Pathologists confirmed that sWSI is reliable enough for standard diagnoses of most tissue categories, while it can be used for quick screening of difficult cases. Conclusions As an ultra-low-cost alternative to whole slide scanners, diagnosis-ready VS quality and robustness for commercial usage is achieved in the sWSI solution. Operated on main-stream smartphones installed on normal optical microscopes, sWSI readily offers affordable and reliable WSI to resource-limited or infrequent clinical users. PMID:28916508

New hardware and workflows for semi-automated correlative cryo-fluorescence and cryo-electron microscopy/tomography.

PubMed

Schorb, Martin; Gaechter, Leander; Avinoam, Ori; Sieckmann, Frank; Clarke, Mairi; Bebeacua, Cecilia; Bykov, Yury S; Sonnen, Andreas F-P; Lihl, Reinhard; Briggs, John A G

2017-02-01

Correlative light and electron microscopy allows features of interest defined by fluorescence signals to be located in an electron micrograph of the same sample. Rare dynamic events or specific objects can be identified, targeted and imaged by electron microscopy or tomography. To combine it with structural studies using cryo-electron microscopy or tomography, fluorescence microscopy must be performed while maintaining the specimen vitrified at liquid-nitrogen temperatures and in a dry environment during imaging and transfer. Here we present instrumentation, software and an experimental workflow that improves the ease of use, throughput and performance of correlated cryo-fluorescence and cryo-electron microscopy. The new cryo-stage incorporates a specially modified high-numerical aperture objective lens and provides a stable and clean imaging environment. It is combined with a transfer shuttle for contamination-free loading of the specimen. Optimized microscope control software allows automated acquisition of the entire specimen area by cryo-fluorescence microscopy. The software also facilitates direct transfer of the fluorescence image and associated coordinates to the cryo-electron microscope for subsequent fluorescence-guided automated imaging. Here we describe these technological developments and present a detailed workflow, which we applied for automated cryo-electron microscopy and tomography of various specimens. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

A novel lobster-eye imaging system based on Schmidt-type objective for X-ray-backscattering inspection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Jie; Wang, Xin, E-mail: wangx@tongji.edu.cn, E-mail: mubz@tongji.edu.cn; Zhan, Qi

This paper presents a novel lobster-eye imaging system for X-ray-backscattering inspection. The system was designed by modifying the Schmidt geometry into a treble-lens structure in order to reduce the resolution difference between the vertical and horizontal directions, as indicated by ray-tracing simulations. The lobster-eye X-ray imaging system is capable of operating over a wide range of photon energies up to 100 keV. In addition, the optics of the lobster-eye X-ray imaging system was tested to verify that they meet the requirements. X-ray-backscattering imaging experiments were performed in which T-shaped polymethyl-methacrylate objects were imaged by the lobster-eye X-ray imaging system basedmore » on both the double-lens and treble-lens Schmidt objectives. The results show similar resolution of the treble-lens Schmidt objective in both the vertical and horizontal directions. Moreover, imaging experiments were performed using a second treble-lens Schmidt objective with higher resolution. The results show that for a field of view of over 200 mm and with a 500 mm object distance, this lobster-eye X-ray imaging system based on a treble-lens Schmidt objective offers a spatial resolution of approximately 3 mm.« less

A novel lobster-eye imaging system based on Schmidt-type objective for X-ray-backscattering inspection

NASA Astrophysics Data System (ADS)

Xu, Jie; Wang, Xin; Zhan, Qi; Huang, Shengling; Chen, Yifan; Mu, Baozhong

2016-07-01

This paper presents a novel lobster-eye imaging system for X-ray-backscattering inspection. The system was designed by modifying the Schmidt geometry into a treble-lens structure in order to reduce the resolution difference between the vertical and horizontal directions, as indicated by ray-tracing simulations. The lobster-eye X-ray imaging system is capable of operating over a wide range of photon energies up to 100 keV. In addition, the optics of the lobster-eye X-ray imaging system was tested to verify that they meet the requirements. X-ray-backscattering imaging experiments were performed in which T-shaped polymethyl-methacrylate objects were imaged by the lobster-eye X-ray imaging system based on both the double-lens and treble-lens Schmidt objectives. The results show similar resolution of the treble-lens Schmidt objective in both the vertical and horizontal directions. Moreover, imaging experiments were performed using a second treble-lens Schmidt objective with higher resolution. The results show that for a field of view of over 200 mm and with a 500 mm object distance, this lobster-eye X-ray imaging system based on a treble-lens Schmidt objective offers a spatial resolution of approximately 3 mm.

Seamless stitching of tile scan microscope images.

PubMed

Legesse, F B; Chernavskaia, O; Heuke, S; Bocklitz, T; Meyer, T; Popp, J; Heintzmann, R

2015-06-01

For diagnostic purposes, optical imaging techniques need to obtain high-resolution images of extended biological specimens in reasonable time. The field of view of an objective lens, however, is often smaller than the sample size. To image the whole sample, laser scanning microscopes acquire tile scans that are stitched into larger mosaics. The appearance of such image mosaics is affected by visible edge artefacts that arise from various optical aberrations which manifest in grey level jumps across tile boundaries. In this contribution, a technique for stitching tiles into a seamless mosaic is presented. The stitching algorithm operates by equilibrating neighbouring edges and forcing the brightness at corners to a common value. The corrected image mosaics appear to be free from stitching artefacts and are, therefore, suited for further image analysis procedures. The contribution presents a novel method to seamlessly stitch tiles captured by a laser scanning microscope into a large mosaic. The motivation for the work is the failure of currently existing methods for stitching nonlinear, multimodal images captured by our microscopic setups. Our method eliminates the visible edge artefacts that appear between neighbouring tiles by taking into account the overall illumination differences among tiles in such mosaics. The algorithm first corrects the nonuniform brightness that exists within each of the tiles. It then compensates for grey level differences across tile boundaries by equilibrating neighbouring edges and forcing the brightness at the corners to a common value. After these artefacts have been removed further image analysis procedures can be applied on the microscopic images. Even though the solution presented here is tailored for the aforementioned specific case, it could be easily adapted to other contexts where image tiles are assembled into mosaics such as in astronomical or satellite photos. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

Research on aspheric focusing lens processing and testing technology in the high-energy laser test system

NASA Astrophysics Data System (ADS)

Liu, Dan; Fu, Xiu-hua; Jia, Zong-he; Wang, Zhe; Dong, Huan

2014-08-01

In the high-energy laser test system, surface profile and finish of the optical element are put forward higher request. Taking a focusing aspherical zerodur lens with a diameter of 100mm as example, using CNC and classical machining method of combining surface profile and surface quality of the lens were investigated. Taking profilometer and high power microscope measurement results as a guide, by testing and simulation analysis, process parameters were improved constantly in the process of manufacturing. Mid and high frequency error were trimmed and improved so that the surface form gradually converged to the required accuracy. The experimental results show that the final accuracy of the surface is less than 0.5μm and the surface finish is □, which fulfils the accuracy requirement of aspherical focusing lens in optical system.

Evaluation of anterior lenticonus in alport syndrome using tracey wavefront aberrometry and transmission electron microscopy.

PubMed

Kim, Kwan Soo; Kim, Mo Sae; Kim, Joon Mo; Choi, Chul Young

2010-01-01

To evaluate the efficacy of Tracey wavefront aberrometry (Tracey Technologies, Houston, TX) and transmission electron microscopy for the detection of anterior lenticonus in Alport syndrome. Tracey wavefront aberrometry was used to treat a patient with bilateral anterior lenticonus who had a history of Alport syndrome. For transmission electron microscopic examination, anterior lens capsules were obtained during clear lens phacoemulsification and intraocular lens implantation. Spherical aberrations were the predominant higher-order aberrations in the internal optics of both eyes. The Tracey wavefront aberrometer showed that most of the irregular astigmatism originated from the lenticular portion. Transmission electron microscopy of the specimens showed anterior lens capsules with decreased thickness and multiple dehiscences. Tracey wavefront aberrometry and transmission electron microscopy are effective tools for evaluation of anterior lenticonus in Alport syndrome. Copyright 2010, SLACK Incorporated.

Comparison of higher-order multiphoton signal generation and collection at the 1700-nm window based on transmittance measurement of objective lenses.

PubMed

Wen, Wenhui; Wang, Yuxin; Liu, Hongji; Wang, Kai; Qiu, Ping; Wang, Ke

2018-01-01

One benefit of excitation at the 1700-nm window is the more accessible modalities of multiphoton signal generation. It is demonstrated here that the transmittance performance of the objective lens is of vital importance for efficient higher-order multiphoton signal generation and collection excited at the 1700-nm window. Two commonly used objective lenses for multiphoton microscopy (MPM) are characterized and compared, one with regular coating and the other with customized coating for high transmittance at the 1700-nm window. Our results show that, fourth harmonic generation imaging of mouse tail tendon and 5-photon fluorescence of carbon quantum dots using the regular objective lens shows an order of magnitude signal higher than those using the customized objective lens. Besides, the regular objective lens also enables a 3-photon fluorescence imaging depth of >1600 μm in mouse brain in vivo. Our results will provide guidelines for objective lens selection for MPM at the 1700-nm window. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wave analysis of a plenoptic system and its applications

NASA Astrophysics Data System (ADS)

Shroff, Sapna A.; Berkner, Kathrin

2013-03-01

Traditional imaging systems directly image a 2D object plane on to the sensor. Plenoptic imaging systems contain a lenslet array at the conventional image plane and a sensor at the back focal plane of the lenslet array. In this configuration the data captured at the sensor is not a direct image of the object. Each lenslet effectively images the aperture of the main imaging lens at the sensor. Therefore the sensor data retains angular light-field information which can be used for a posteriori digital computation of multi-angle images and axially refocused images. If a filter array, containing spectral filters or neutral density or polarization filters, is placed at the pupil aperture of the main imaging lens, then each lenslet images the filters on to the sensor. This enables the digital separation of multiple filter modalities giving single snapshot, multi-modal images. Due to the diversity of potential applications of plenoptic systems, their investigation is increasing. As the application space moves towards microscopes and other complex systems, and as pixel sizes become smaller, the consideration of diffraction effects in these systems becomes increasingly important. We discuss a plenoptic system and its wave propagation analysis for both coherent and incoherent imaging. We simulate a system response using our analysis and discuss various applications of the system response pertaining to plenoptic system design, implementation and calibration.

Karl Otto Himmler, manufacturer of the first contact lens.

PubMed

Pearson, Richard M

2007-03-01

In 1889 August Müller (1864-1949) reported the correction of his own high myopia with a ground scleral contact lens that had been manufactured in Berlin two years earlier. This paper provides the first conclusive identification, based upon primary sources, of the manufacturer of these lenses. They were made by an optical engineer, Karl Otto Himmler (1841-1903), whose firm enjoyed, until the outbreak of World War II, an international reputation for the manufacture of microscopes and their accessories.

Lens Designers Are Real People Too

NASA Astrophysics Data System (ADS)

Kingslake, Rudolf

1986-02-01

This informal evening lecture covered briefly the careers and accomplishments of some of the more interesting lens designers and opticians of the past. Starting in the 1600s with the early astronomers and microscope makers, this was followed by the makers of photographic lenses after the introduction of photography in 1839. Numerous portraits of early workers were shown. The names of people specifically covered in this talk are listed below. Some other names were mentioned without comment; these are not included here.

Negative ratings play a positive role in information filtering

NASA Astrophysics Data System (ADS)

Zeng, Wei; Zhu, Yu-Xiao; Lü, Linyuan; Zhou, Tao

2011-11-01

The explosive growth of information asks for advanced information filtering techniques to solve the so-called information overload problem. A promising way is the recommender system which analyzes the historical records of users’ activities and accordingly provides personalized recommendations. Most recommender systems can be represented by user-object bipartite networks where users can evaluate and vote for objects, and ratings such as “dislike” and “I hate it” are treated straightforwardly as negative factors or are completely ignored in traditional approaches. Applying a local diffusion algorithm on three benchmark data sets, MovieLens, Netflix and Amazon, our study arrives at a very surprising result, namely the negative ratings may play a positive role especially for very sparse data sets. In-depth analysis at the microscopic level indicates that the negative ratings from less active users to less popular objects could probably have positive impacts on the recommendations, while the ones connecting active users and popular objects mostly should be treated negatively. We finally outline the significant relevance of our results to the two long-term challenges in information filtering: the sparsity problem and the cold-start problem.

Field modeling and ray-tracing of a miniature scanning electron microscope beam column.

PubMed

Loyd, Jody S; Gregory, Don A; Gaskin, Jessica A

2017-08-01

A miniature scanning electron microscope (SEM) focusing column design is introduced and its potential performance assessed through an estimation of parameters that affect the probe radius, to include source size, spherical and chromatic aberration, diffraction and space charge broadening. The focusing column, a critical component of any SEM capable of operating on the lunar surface, was developed by the NASA Marshall Space Flight Center and Advanced Research Systems. The ray-trace analysis presented uses a model of the electrostatic field (within the focusing column) that is first calculated using the boundary element method (BEM). This method provides flexibility in modeling the complex electrode shapes of practical electron lens systems. A Fourier series solution of the lens field is then derived within a cylindrical domain whose boundary potential is provided by the BEM. Used in this way, the Fourier series solution is an accuracy enhancement to the BEM solution, allowing sufficient precision to assess geometric aberrations through direct ray-tracing. Two modes of operation with distinct lens field solutions are described. © The Author 2017. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Electron microscopic examination of the anterior lens capsule in a case of Alport's syndrome.

PubMed

Citirik, Mehmet; Batman, Cosar; Men, Gamze; Tuncel, Murvet; Zilelioglu, Orhan

2007-09-01

To report a case of Alport's syndrome and to present electronmicroscopic examination findings of the anterior lens capsule of this patient. A 21-year-old man was referred for low visual acuity and retinal pigment epithelial changes in the left eye. The patient and his relatives underwent detailed ophthalmological examination, including electrophysiological testing. The patient also underwent electronmicroscopic examination of the anterior lens capsule. His visual acuity was 6/18 OD and 6/15 OS. Anterior lenticonus and subcapsular opacities were observed in the left eye. Cataract extraction by phacoemulsification with intraocular lens implantation was performed for his poor visual performance. During the capsulorhexis, the remarkably thin and fragile anterior capsule was noted and removed. Ultrastructural analysis of the anterior lens capsule showed a thinner central zone compared with the periphery. The course of Alport's syndrome can be ameliorated by early diagnosis. Therefore, the ophthalmological examination of a patient with anterior lenticonus must be combined with a detailed medical evaluation. Ultrastructural analysis of the lens capsule can support the diagnosis of Alport's syndrome.

Optical path difference microscopy with a Shack-Hartmann wavefront sensor.

PubMed

Gong, Hai; Agbana, Temitope E; Pozzi, Paolo; Soloviev, Oleg; Verhaegen, Michel; Vdovin, Gleb

2017-06-01

In this Letter, we show that a Shack-Hartmann wavefront sensor can be used for the quantitative measurement of the specimen optical path difference (OPD) in an ordinary incoherent optical microscope, if the spatial coherence of the illumination light in the plane of the specimen is larger than the microscope resolution. To satisfy this condition, the illumination numerical aperture should be smaller than the numerical aperture of the imaging lens. This principle has been successfully applied to build a high-resolution reference-free instrument for the characterization of the OPD of micro-optical components and microscopic biological samples.

Three-dimensional particle tracking via tunable color-encoded multiplexing.

PubMed

Duocastella, Martí; Theriault, Christian; Arnold, Craig B

2016-03-01

We present a novel 3D tracking approach capable of locating single particles with nanometric precision over wide axial ranges. Our method uses a fast acousto-optic liquid lens implemented in a bright field microscope to multiplex light based on color into different and selectable focal planes. By separating the red, green, and blue channels from an image captured with a color camera, information from up to three focal planes can be retrieved. Multiplane information from the particle diffraction rings enables precisely locating and tracking individual objects up to an axial range about 5 times larger than conventional single-plane approaches. We apply our method to the 3D visualization of the well-known coffee-stain phenomenon in evaporating water droplets.

Optical track width measurements below 100 nm using artificial neural networks

NASA Astrophysics Data System (ADS)

Smith, R. J.; See, C. W.; Somekh, M. G.; Yacoot, A.; Choi, E.

2005-12-01

This paper discusses the feasibility of using artificial neural networks (ANNs), together with a high precision scanning optical profiler, to measure very fine track widths that are considerably below the conventional diffraction limit of a conventional optical microscope. The ANN is trained using optical profiles obtained from tracks of known widths, the network is then assessed by applying it to test profiles. The optical profiler is an ultra-stable common path scanning interferometer, which provides extremely precise surface measurements. Preliminary results, obtained with a 0.3 NA objective lens and a laser wavelength of 633 nm, show that the system is capable of measuring a 50 nm track width, with a standard deviation less than 4 nm.

Confocal Microscopy Imaging with an Optical Transition Edge Sensor

NASA Astrophysics Data System (ADS)

Fukuda, D.; Niwa, K.; Hattori, K.; Inoue, S.; Kobayashi, R.; Numata, T.

2018-05-01

Fluorescence color imaging at an extremely low excitation intensity was performed using an optical transition edge sensor (TES) embedded in a confocal microscope for the first time. Optical TES has the ability to resolve incident single photon energy; therefore, the wavelength of each photon can be measured without spectroscopic elements such as diffraction gratings. As target objects, animal cells labeled with two fluorescent dyes were irradiated with an excitation laser at an intensity below 1 μW. In our confocal system, an optical fiber-coupled TES device is used to detect photons instead of the pinhole and photomultiplier tube used in typical confocal microscopes. Photons emitted from the dyes were collected by the objective lens, and sent to the optical TES via the fiber. The TES measures the wavelength of each photon arriving in an exposure time of 70 ms, and a fluorescent photon spectrum is constructed. This measurement is repeated by scanning the target sample, and finally a two-dimensional RGB-color image is obtained. The obtained image showed that the photons emitted from the dyes of mitochondria and cytoskeletons were clearly resolved at a detection intensity level of tens of photons. TES exhibits ideal performance as a photon detector with a low dark count rate (< 1 Hz) and wavelength resolving power. In the single-mode fiber-coupled system, the confocal microscope can be operated in the super-resolution mode. These features are very promising to realize high-sensitivity and high-resolution photon spectral imaging, and would help avoid cell damage and photobleaching of fluorescence dyes.

High bandwidth deflection readout for atomic force microscopes.

PubMed

Steininger, Juergen; Bibl, Matthias; Yoo, Han Woong; Schitter, Georg

2015-10-01

This contribution presents the systematic design of a high bandwidth deflection readout mechanism for atomic force microscopes. The widely used optical beam deflection method is revised by adding a focusing lens between the cantilever and the quadrant photodetector (QPD). This allows the utilization of QPDs with a small active area resulting in an increased detection bandwidth due to the reduced junction capacitance. Furthermore the additional lens can compensate a cross talk between a compensating z-movement of the cantilever and the deflection readout. Scaling effects are analyzed to get the optimal spot size for the given geometry of the QPD. The laser power is tuned to maximize the signal to noise ratio without limiting the bandwidth by local saturation effects. The systematic approach results in a measured -3 dB detection bandwidth of 64.5 MHz at a deflection noise density of 62fm/√Hz.

High bandwidth deflection readout for atomic force microscopes

NASA Astrophysics Data System (ADS)

Steininger, Juergen; Bibl, Matthias; Yoo, Han Woong; Schitter, Georg

2015-10-01

This contribution presents the systematic design of a high bandwidth deflection readout mechanism for atomic force microscopes. The widely used optical beam deflection method is revised by adding a focusing lens between the cantilever and the quadrant photodetector (QPD). This allows the utilization of QPDs with a small active area resulting in an increased detection bandwidth due to the reduced junction capacitance. Furthermore the additional lens can compensate a cross talk between a compensating z-movement of the cantilever and the deflection readout. Scaling effects are analyzed to get the optimal spot size for the given geometry of the QPD. The laser power is tuned to maximize the signal to noise ratio without limiting the bandwidth by local saturation effects. The systematic approach results in a measured -3 dB detection bandwidth of 64.5 MHz at a deflection noise density of 62 fm / √{ Hz } .

The structural damages of lens crystallins induced by peroxynitrite and methylglyoxal, two causative players in diabetic complications and preventive role of lens antioxidant components.

PubMed

Moghadam, Sogand Sasan; Oryan, Ahmad; Kurganov, Boris I; Tamaddon, Ali-Mohammad; Alavianehr, Mohammad Mehdi; Moosavi-Movahedi, Ali Akbar; Yousefi, Reza

2017-10-01

Peroxynitrite (PON) and methylglyoxal (MGO), two diabetes-associated compounds, are believed to be important causative players in development of diabetic cataracts. In the current study, different spectroscopic methods, gel electrophoresis, lens culture and microscopic assessments were applied to examine the impact of individual, subsequent or simultaneous modification of lens crystallins with MGO and PON on their structure, oligomerization and aggregation. The protein modifications were confirmed with detection of the significantly increased quantity of carbonyl groups and decreased levels of sulfhydryl, tyrosine and tryptophan. Also, lens proteins modification with these chemical agents was accompanied with important structural alteration, oligomerization, disulfide/chromophore mediated protein crosslinking and important proteolytic instability. All these structural damages were more pronounced when the lens proteins were modified in the presence of both mentioned chemical agents, either in sequential or simultaneous manner. Ascorbic acid and glutathione, as the main components of lens antioxidant defense mechanism, were also capable to markedly prevent the damaging effects of PON and MGO on lens crystallins, as indicated by gel electrophoresis. The results of this study may highlight the importance of lens antioxidant defense system in protection of crystallins against the structural insults induced by PON and MGO during chronic hyperglycemia in the diabetic patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Aberration corrected STEM by means of diffraction gratings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Linck, Martin; Ercius, Peter A.; Pierce, Jordan S.

In the past 15 years, the advent of aberration correction technology in electron microscopy has enabled materials analysis on the atomic scale. This is made possible by precise arrangements of multipole electrodes and magnetic solenoids to compensate the aberrations inherent to any focusing element of an electron microscope. In this paper, we describe an alternative method to correct for the spherical aberration of the objective lens in scanning transmission electron microscopy (STEM) using a passive, nanofabricated diffractive optical element. This holographic device is installed in the probe forming aperture of a conventional electron microscope and can be designed to removemore » arbitrarily complex aberrations from the electron's wave front. In this work, we show a proof-of-principle experiment that demonstrates successful correction of the spherical aberration in STEM by means of such a grating corrector (GCOR). Our GCOR enables us to record aberration-corrected high-resolution high-angle annular dark field (HAADF-) STEM images, although yet without advancement in probe current and resolution. Finally, improvements in this technology could provide an economical solution for aberration-corrected high-resolution STEM in certain use scenarios.« less

Aberration corrected STEM by means of diffraction gratings

DOE PAGES

Linck, Martin; Ercius, Peter A.; Pierce, Jordan S.; ...

2017-06-12

In the past 15 years, the advent of aberration correction technology in electron microscopy has enabled materials analysis on the atomic scale. This is made possible by precise arrangements of multipole electrodes and magnetic solenoids to compensate the aberrations inherent to any focusing element of an electron microscope. In this paper, we describe an alternative method to correct for the spherical aberration of the objective lens in scanning transmission electron microscopy (STEM) using a passive, nanofabricated diffractive optical element. This holographic device is installed in the probe forming aperture of a conventional electron microscope and can be designed to removemore » arbitrarily complex aberrations from the electron's wave front. In this work, we show a proof-of-principle experiment that demonstrates successful correction of the spherical aberration in STEM by means of such a grating corrector (GCOR). Our GCOR enables us to record aberration-corrected high-resolution high-angle annular dark field (HAADF-) STEM images, although yet without advancement in probe current and resolution. Finally, improvements in this technology could provide an economical solution for aberration-corrected high-resolution STEM in certain use scenarios.« less

Mapping optical path length and image enhancement using quantitative orientation-independent differential interference contrast microscopy

PubMed Central

Shribak, Michael; Larkin, Kieran G.; Biggs, David

2017-01-01

Abstract. We describe the principles of using orientation-independent differential interference contrast (OI-DIC) microscopy for mapping optical path length (OPL). Computation of the scalar two-dimensional OPL map is based on an experimentally received map of the OPL gradient vector field. Two methods of contrast enhancement for the OPL image, which reveal hardly visible structures and organelles, are presented. The results obtained can be used for reconstruction of a volume image. We have confirmed that a standard research grade light microscope equipped with the OI-DIC and 100×/1.3 NA objective lens, which was not specially selected for minimum wavefront and polarization aberrations, provides OPL noise level of ∼0.5  nm and lateral resolution if ∼300  nm at a wavelength of 546 nm. The new technology is the next step in the development of the DIC microscopy. It can replace standard DIC prisms on existing commercial microscope systems without modification. This will allow biological researchers that already have microscopy setups to expand the performance of their systems. PMID:28060991

The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.

We report the results of searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verification and Year 1 observations. The Science Verification data span approximately 250 sq. deg. with a median i -band limiting magnitude for extended objects (10 σ ) of 23.0. The Year 1 data span approximately 2000 sq. deg. and have an i -band limiting magnitude for extended objects (10 σ ) of 22.9. As these data sets are both wide and deep, they are particularly useful for identifying strong gravitational lens candidates. Potential strong gravitational lens candidate systems were initially identified basedmore » on a color and magnitude selection in the DES object catalogs or because the system is at the location of a previously identified galaxy cluster. Cutout images of potential candidates were then visually scanned using an object viewer and numerically ranked according to whether or not we judged them to be likely strong gravitational lens systems. Having scanned nearly 400,000 cutouts, we present 374 candidate strong lens systems, of which 348 are identified for the first time. We provide the R.A. and decl., the magnitudes and photometric properties of the lens and source objects, and the distance (radius) of the source(s) from the lens center for each system.« less

The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

NASA Astrophysics Data System (ADS)

Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.; Nord, B.; Gaitsch, H.; Gaitsch, S.; Lin, H.; Allam, S.; Collett, T. E.; Furlanetto, C.; Gill, M. S. S.; More, A.; Nightingale, J.; Odden, C.; Pellico, A.; Tucker, D. L.; da Costa, L. N.; Fausti Neto, A.; Kuropatkin, N.; Soares-Santos, M.; Welch, B.; Zhang, Y.; Frieman, J. A.; Abdalla, F. B.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; D'Andrea, C. B.; Desai, S.; Dietrich, J. P.; Drlica-Wagner, A.; Evrard, A. E.; Finley, D. A.; Flaugher, B.; García-Bellido, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; James, D. J.; Kuehn, K.; Kuhlmann, S.; Lahav, O.; Li, T. S.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Menanteau, F.; Miquel, R.; Nichol, R. C.; Nugent, P.; Ogando, R. L. C.; Plazas, A. A.; Reil, K.; Romer, A. K.; Sako, M.; Sanchez, E.; Santiago, B.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.; DES Collaboration

2017-09-01

We report the results of searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verification and Year 1 observations. The Science Verification data span approximately 250 sq. deg. with a median I-band limiting magnitude for extended objects (10σ) of 23.0. The Year 1 data span approximately 2000 sq. deg. and have an I-band limiting magnitude for extended objects (10σ) of 22.9. As these data sets are both wide and deep, they are particularly useful for identifying strong gravitational lens candidates. Potential strong gravitational lens candidate systems were initially identified based on a color and magnitude selection in the DES object catalogs or because the system is at the location of a previously identified galaxy cluster. Cutout images of potential candidates were then visually scanned using an object viewer and numerically ranked according to whether or not we judged them to be likely strong gravitational lens systems. Having scanned nearly 400,000 cutouts, we present 374 candidate strong lens systems, of which 348 are identified for the first time. We provide the R.A. and decl., the magnitudes and photometric properties of the lens and source objects, and the distance (radius) of the source(s) from the lens center for each system.

Field-testing of a cost-effective mobile-phone based microscope for screening of Schistosoma haematobium infection (Conference Presentation)

NASA Astrophysics Data System (ADS)

Ceylan Koydemir, Hatice; Bogoch, Isaac I.; Tseng, Derek; Ephraim, Richard K. D.; Duah, Evans; Tee, Joseph; Andrews, Jason R.; Ozcan, Aydogan

2016-03-01

Schistosomiasis is a parasitic and neglected tropical disease, and affects <200-million people across the world, with school-aged children disproportionately affected. Here we present field-testing results of a handheld and cost effective smartphone-based microscope in rural Ghana, Africa, for point-of-care diagnosis of S. haematobium infection. In this mobile-phone microscope, a custom-designed 3D printed opto-mechanical attachment (~150g) is placed in contact with the smartphone camera-lens, creating an imaging-system with a half-pitch resolution of ~0.87µm. This unit includes an external lens (also taken from a mobile-phone camera), a sample tray, a z-stage to adjust the focus, two light-emitting-diodes (LEDs) and two diffusers for uniform illumination of the sample. In our field-testing, 60 urine samples, collected from children, were used, where the prevalence of the infection was 72.9%. After concentration of the sample with centrifugation, the sediment was placed on a glass-slide and S. haematobium eggs were first identified/quantified using conventional benchtop microscopy by an expert diagnostician, and then a second expert, blinded to these results, determined the presence/absence of eggs using our mobile-phone microscope. Compared to conventional microscopy, our mobile-phone microscope had a diagnostic sensitivity of 72.1%, specificity of 100%, positive-predictive-value of 100%, and a negative-predictive-value of 57.1%. Furthermore, our mobile-phone platform demonstrated a sensitivity of 65.7% and 100% for low-intensity infections (≤50 eggs/10 mL urine) and high-intensity infections (<50 eggs/10 mL urine), respectively. We believe that this cost-effective and field-portable mobile-phone microscope may play an important role in the diagnosis of schistosomiasis and various other global health challenges.

Chromatic confocal microscope using hybrid aspheric diffractive lenses

NASA Astrophysics Data System (ADS)

Rayer, Mathieu; Mansfield, Daniel

2014-05-01

A chromatic confocal microscope is a single point non-contact distance measurement sensor. For three decades the vast majority of the chromatic confocal microscope use refractive-based lenses to code the measurement axis chromatically. However, such an approach is limiting the range of applications. In this paper the performance of refractive, diffractive and Hybrid aspheric diffractive are compared. Hybrid aspheric diffractive lenses combine the low geometric aberration of a diffractive lens with the high optical power of an aspheric lens. Hybrid aspheric diffractive lenses can reduce the number of elements in an imaging system significantly or create large hyper- chromatic lenses for sensing applications. In addition, diffractive lenses can improve the resolution and the dynamic range of a chromatic confocal microscope. However, to be suitable for commercial applications, the diffractive optical power must be significant. Therefore, manufacturing such lenses is a challenge. We show in this paper how a theoretical manufacturing model can demonstrate that the hybrid aspheric diffractive configuration with the best performances is achieved by step diffractive surface. The high optical quality of step diffractive surface is then demonstrated experimentally. Publisher's Note: This paper, originally published on 5/10/14, was replaced with a corrected/revised version on 5/19/14. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.

Operating microscope light-induced phototoxic maculopathy after transscleral sutured posterior chamber intraocular lens implantation.

PubMed

Kweon, Eui Yong; Ahn, Min; Lee, Dong Wook; You, In Cheon; Kim, Min Jung; Cho, Nam Chun

2009-01-01

The purpose of this study is to report the features of operating microscope light-induced retinal phototoxic maculopathy after transscleral sutured posterior chamber intraocular lens (TSS PC-IOL) implantation. The charts of 118 patients who underwent TSS PC-IOL implantation surgery at Chonbuk National University Hospital (Jeonju, Korea) between March 1999 and February 2008 were retrospectively reviewed. Fourteen patients underwent combined 3-port pars plana vitrectomy and TSS PC-IOL implantation (vitrectomy group), and 104 patients underwent TSS PC-IOL implantation only (nonvitrectomy group). All surgeries were performed under the same coaxial illuminated microscope. All diagnoses were confirmed through careful fundus examination and fluorescein angiography (FA). Diagnoses of retinal phototoxic maculopathy were established in 10 (8.47%) of 118 TSS PC-IOL implantation cases. Phototoxic maculopathy occurred more frequently in the vitrectomy group than in the nonvitrectomy group (6/14 versus 4/104, respectively; P < 0.001, chi-square = 24.21). Affected patients reported decreased vision and were found to have coarse alterations of the retinal pigment epithelium (RPE). In 5 of the phototoxic maculopathy cases (50%), the visual acuity was 20/200 or worse. Operating microscope light-induced retinal phototoxic maculopathy can occur more frequently after TSS PC-IOL implantation than after casual cataract surgery, especially when TSS PC-IOL is combined with vitrectomy surgery. Surgeons should take precautions to prevent retinal phototoxicity after TSS PC-IOL implantation and vitrectomy.

Experimental far-field imaging properties of a ~5-μm diameter spherical lens.

PubMed

Ye, Ran; Ye, Yong-Hong; Ma, Hui Feng; Ma, Jun; Wang, Bin; Yao, Jie; Liu, Shuai; Cao, Lingling; Xu, Huanhuan; Zhang, Jia-Yu

2013-06-01

Microscale lenses are mostly used as near-sighted lenses. The far-field imaging properties of a microscale spherical lens, where the lens is spatially separated from the object, are experimentally studied. Our experimental results show that, for a blu-ray disc (an object) whose spacing is 300 nm, the lens can magnify the stripe patterns of the disc when the lens is spatially separated from the object. In the experimentally tested range (0-14 μm), all the magnified images are virtual images. When the distance is increased from 0 to 14 μm the magnification decreases from 1.47× to 1.20× and the field of view increases from 3.8 to 12.2 μm. The image magnification cannot be described by standard geometrical optics.

Diffraction limited focusing and routing of gap plasmons by a metal-dielectric-metal lens

DOE PAGES

Dennis, Brian S.; Czaplewski, David A.; Haftel, Michael I.; ...

2015-08-12

Passive optical elements can play key roles in photonic applications such as plasmonic integrated circuits. Here we experimentally demonstrate passive gap-plasmon focusing and routing in two-dimensions. This is accomplished using a high numerical-aperture metal-dielectric-metal lens incorporated into a planar-waveguide device. Fabrication via metal sputtering, oxide deposition, electron- and focused-ion- beam lithography, and argon ion-milling is reported on in detail. Diffraction-limited focusing is optically characterized by sampling out-coupled light with a microscope. The measured focal distance and full-width-half-maximum spot size agree well with the calculated lens performance. The surface plasmon polariton propagation length is measured by sampling light from multiple out-couplermore » slits.« less

Postoperative diffuse opacification of a hydrophilic acrylic intraocular lens: analysis of an explant.

PubMed

Cavallini, Gian Maria; Volante, Veronica; Campi, Luca; De Maria, Michele; Fornasari, Elisa; Urso, Giancarlo

2017-06-14

We describe the clinicopathological and ultrastructural features of an opaque single-piece hydrophilic acrylic intraocular lens (IOL) explanted from a patient. The main outcome of this report is the documentation of calcium deposits confirmed by surface analysis. The decrease in visual acuity was due to the opacification of the IOL. The opacification involved both the optic plate and the haptics. The analysis at the scansion electron microscope revealed that the opacity was caused by the deposition of calcium and phosphate within the lens optic and haptics. This is the first case about the opacification of an Oculentis L-313. The opacification was characterized by calcium and phosphate deposition probably due to a morphological alteration of the posterior surface of the IOL.

Converging or Diverging Lens?

ERIC Educational Resources Information Center

Branca, Mario

2013-01-01

Why does a lens magnify? Why does it shrink objects? Why does this happen? The activities that we propose here are useful in helping us to understand how lenses work, and they show that the same lens can have different magnification capabilities. A converging lens can also act as a diverging lens. (Contains 4 figures.)

Objective lens simultaneously optimized for pupil ghosting, wavefront delivery and pupil imaging

NASA Technical Reports Server (NTRS)

Olczak, Eugene G (Inventor)

2011-01-01

An objective lens includes multiple optical elements disposed between a first end and a second end, each optical element oriented along an optical axis. Each optical surface of the multiple optical elements provides an angle of incidence to a marginal ray that is above a minimum threshold angle. This threshold angle minimizes pupil ghosts that may enter an interferometer. The objective lens also optimizes wavefront delivery and pupil imaging onto an optical surface under test.

A clinical pathologic study of mercurialentis medicamentosus.

PubMed

Garron, L K; Wood, I S; Spencer, W H; Hayes, T L

1976-01-01

Thirty-one patients who used eye drops containing the preservative, phenylmercuric nitrate for from 3 to 15 years, developed a brownish pigmentation of the anterior capsule of the pupillary area. Light and electron microscopic studies on two lenses demonstrated deposits of dense particulate material resembling melanin pigment on and in the anterior capsule of the lens in the area of the pupil. Special studies, including electron microprobe analysis and neutron activation analysis established the presence of mercury in a lens with mercurialentis. No mercury was found in two lenses used as controls.

Variable-Size Bead Layer as Standard Reference for Endothelial Microscopes.

PubMed

Tufo, Simona; Prazzoli, Erica; Ferraro, Lorenzo; Cozza, Federica; Borghesi, Alessandro; Tavazzi, Silvia

2017-02-01

For morphometric analysis of the cell mosaic of corneal endothelium, checking accuracy and precision of instrumentation is a key step. In this study, a standard reference sample is proposed, developed to reproduce the cornea with its shape and the endothelium with its intrinsic variability in the cell size. A polystyrene bead layer (representing the endothelium) was deposited on a lens (representing the cornea). Bead diameters were 20, 25, and 30 μm (fractions in number 55%, 30%, and 15%, respectively). Bead density and hexagonality were simulated to obtain the expected true values and measured using a slit-lamp endothelial microscope applied to 1) a Takagi 700GL slit lamp at 40× magnification (recommended standard setup) and 2) a Takagi 2ZL slit lamp at 25× magnification. The simulation provided the expected bead density 2001 mm and hexagonality 47%. At 40×, density and hexagonality were measured to be 2009 mm (SD 93 mm) and 45% (SD 3%). At 25× on a different slit lamp, the comparison between measured and expected densities provided the factor 1.526 to resize the image and to use the current algorithms of the slit-lamp endothelial microscope for cell recognition. A variable-size polystyrene bead layer on a lens is proposed as a standard sample mimicking the real shape of the cornea and the variability of cell size and cell arrangement of corneal endothelium. The sample is suggested to evaluate accuracy and precision of cell density and hexagonality obtained by different endothelial microscopes, including a slit-lamp endothelial microscope applied to different slit lamps, also at different magnifications.

A Novel Quantitative 500-MHz Acoustic-microscopy System for Ophthalmologic Tissues

PubMed Central

Rohrbach, Daniel; Jakob, Anette; Lloyd, Harriet O.; Tretbar, Steffen H.; Silverman, Ronald H.; Mamou, Jonathan

2017-01-01

Objective This paper describes development of a novel 500-MHz scanning acoustic microscope (SAM) for assessing the mechanical properties of ocular tissues at fine resolution. The mechanical properties of some ocular tissues, such as lamina cribrosa (LC) in the optic nerve head, are believed to play a pivotal role in eye pathogenesis. Methods A novel etching technology was used to fabricate silicon-based lens for a 500-MHz transducer. The transducer was tested in a custom designed scanning system on human eyes. Two-dimensional (2D) maps of bulk modulus (K), mass density (ρ) were derived using improved versions of current state-of-the-art signal processing approaches. Results The transducer employed a lens radius of 125 μm and had a center frequency of 479 MHz with a −6-dB bandwidth of 264 MHz and a lateral resolution of 4 μm. The LC, Bruch’s membrane (BM) at the interface of the retina and choroid, and Bowman’s layer (BL) at the interface of the corneal epithelium and stroma, were successfully imaged and resolved. Analysis of the 2D parameter maps revealed average values of LC, BM and BL with KLC = 2.81 ± 0.17; GPa, KBM = 2.89 ± 0.18; GPa, K BL = 2.6 ± 0.09; GPa, ρ LC = 0.96 ± 0.03 g/cm3; ρ BM = 0.97 ± 0.04 g/cm3; ρ BL = 0.98 ± 0.04g/cm3; Significance This novel SAM was shown to be capable of measuring mechanical properties of soft biological tissues at microscopic resolution; it currently is the only system that allows Simultaneous measurement of K, ρ, and attenuation in large lateral scales (field area > 9 mm2) and at fine resolutions. PMID:27249824

Direct view zoom scope with single focal plane and adaptable reticle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bagwell, Brett

A direct view telescopic sight includes objective lens, eyepiece, and prism erector assemblies. The objective lens assembly is mounted to receive light of an image from an object direction and direct the light along an optical path. The eyepiece assembly is mounted to receive the light along the optical path and to emit the light of the image along an eye-ward direction. The prism erector assembly is positioned between the objective lens and eyepiece assemblies and includes first and second prism elements through which the optical path passes. The first and second prism elements invert the image. A reticle elementmore » is disposed on or adjacent to a surface of one of the first or second prism elements to combine a reticle on the image. The image is brought into focus at only a single focal plane between the objective lens and eyepiece assemblies at a given time.« less

Distortion Correction for a Brewster Angle Microscope Using an Optical Grating.

PubMed

Sun, Zhe; Zheng, Desheng; Baldelli, Steven

2017-02-21

A distortion-corrected Brewster angle microscope (DC-BAM) is designed, constructed, and tested based on the combination of an optical grating and a relay lens. Avoiding the drawbacks of most conventional BAM instruments, this configuration corrects the image propagation direction and consequently provides an image in focus over the entire field of view without any beam scanning or imaging reconstruction. This new BAM can be applied to both liquid and solid subphases with good spatial resolution in static and dynamic studies.

High Resolution Higher Energy X-ray Microscope for Mesoscopic Materials

NASA Astrophysics Data System (ADS)

Snigireva, I.; Snigirev, A.

2013-10-01

We developed a novel X-ray microscopy technique to study mesoscopically structured materials, employing compound refractive lenses. The easily seen advantage of lens-based methodology is the possibility to retrieve high resolution diffraction pattern and real-space images in the same experimental setup. Methodologically the proposed approach is similar to the studies of crystals by high resolution transmission electron microscopy. The proposed microscope was applied for studying of mesoscopic materials such as natural and synthetic opals, inverted photonic crystals.

A handheld MEMS-based line-scanned dual-axis confocal microscope for early cancer detection and surgical guidance (Conference Presentation)

NASA Astrophysics Data System (ADS)

Chen, Ye; Yin, Chengbo; Wei, Linpeng; Glaser, Adam K.; Abeytunge, Sanjee; Peterson, Gary; Mandella, Michael J.; Sanai, Nader; Rajadhyaksha, Milind; Liu, Jonathan T.

2017-02-01

Considerable efforts have been recently undertaken to develop miniature optical-sectioning microscopes for in vivo microendoscopy and point-of-care pathology. These devices enable in vivo interrogation of disease as a real-time and noninvasive alternative to gold-standard histopathology, and therefore could have a transformative impact for the early detection of cancer as well as for guiding tumor-resection procedures. Regardless of the specific modality, various trade-offs in size, speed, field of view, resolution, contrast, and sensitivity are necessary to optimize a device for a particular application. Here, a miniature MEMS-based line-scanned dual-axis confocal (LS-DAC) microscope, with a 12-mm diameter distal tip, has been developed for point-of-care pathology. The dual-axis architecture has demonstrated superior rejection of out-of-focus and multiply scattered photons compared to a conventional single-axis confocal configuration. The use of line scanning enables fast frame rates (≥15 frames/sec), which mitigates motion artifacts of a handheld device during clinical use. We have developed a method to actively align the illumination and collection beams in this miniature LS-DAC microscope through the use of a pair of rotatable alignment mirrors. Incorporation of a custom objective lens, with a small form factor for in vivo application, enables the device to achieve an axial and lateral resolution of 2.0 and 1.1 microns, respectively. Validation measurements with reflective targets, as well as in vivo and ex vivo images of tissues, demonstrate that this high-speed LS-DAC microscope can achieve high-contrast imaging of fluorescently labeled tissues with sufficient sensitivity for applications such as oral cancer detection and guiding brain-tumor resections.

Miniature in vivo MEMS-based line-scanned dual-axis confocal microscope for point-of-care pathology

PubMed Central

Yin, C.; Glaser, A.K.; Leigh, S. Y.; Chen, Y.; Wei, L.; Pillai, P. C. S.; Rosenberg, M. C.; Abeytunge, S.; Peterson, G.; Glazowski, C.; Sanai, N.; Mandella, M. J.; Rajadhyaksha, M.; Liu, J. T. C.

2016-01-01

There is a need for miniature optical-sectioning microscopes to enable in vivo interrogation of tissues as a real-time and noninvasive alternative to gold-standard histopathology. Such devices could have a transformative impact for the early detection of cancer as well as for guiding tumor-resection procedures. Miniature confocal microscopes have been developed by various researchers and corporations to enable optical sectioning of highly scattering tissues, all of which have necessitated various trade-offs in size, speed, depth selectivity, field of view, resolution, image contrast, and sensitivity. In this study, a miniature line-scanned (LS) dual-axis confocal (DAC) microscope, with a 12-mm diameter distal tip, has been developed for clinical point-of-care pathology. The dual-axis architecture has demonstrated an advantage over the conventional single-axis confocal configuration for reducing background noise from out-of-focus and multiply scattered light. The use of line scanning enables fast frame rates (16 frames/sec is demonstrated here, but faster rates are possible), which mitigates motion artifacts of a hand-held device during clinical use. We have developed a method to actively align the illumination and collection beams in a DAC microscope through the use of a pair of rotatable alignment mirrors. Incorporation of a custom objective lens, with a small form factor for in vivo clinical use, enables our device to achieve an optical-sectioning thickness and lateral resolution of 2.0 and 1.1 microns respectively. Validation measurements with reflective targets, as well as in vivo and ex vivo images of tissues, demonstrate the clinical potential of this high-speed optical-sectioning microscopy device. PMID:26977337

Morphology of contact lens-induced conjunctival epithelial flaps: a pilot study.

PubMed

Bergmanson, Jan P G; Tukler, Johanna; Leach, Norman E; Alabdelmoneam, Mussaed; Miller, William L

2012-08-01

Conjunctival epithelial flap (CEF) is a conjunctival condition most commonly seen in silicone hydrogel contact lens wearers. This study utilized impression cytology to investigate the cellular composition and health of CEFs. Nine (9) subjects were enrolled - 3 non-lens wearers, 3 contact lens wearers without CEF, and 3 contact lens wearers with CEFs wearing 8.4/13.8 lotrafilcon A lenses. Impression cytology samples were collected from the flap or similar locations, if CEF was absent, using rectangular 5 mm × 2 mm Millipore HAWP02500 membrane filters. The filters were gently pressed onto the conjunctiva, subsequently fixed in 95% alcohol, stained with hematoxylin-eosin and evaluated under an Olympus IX70 microscope. Measurements of the longest cell and nucleus dimensions were measured on 40 cells from each filter by utilizing NIH Image 1.63. CEF consisted of multilayers of epithelial and goblet cells and were devoid of inflammatory cells, basement membrane material and stromal tissue. The cytoplasmic and nuclear dimensions were similar within the groups and the cytoplasm-to-nucleus ratio was not different between the flap group and the non-lens wearing group. The CEF appeared to be formed by healthy epithelial and goblet cells that have been dislocated from their normal location along the conjunctival surface by the lens edge. No inflammatory cells were present in this contact lens induced condition, which is reported to be associated most commonly with the silicone hydrogel material. Copyright © 2012 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Epi-Fluorescence Microscopy

PubMed Central

Webb, Donna J.; Brown, Claire M.

2012-01-01

Epi-fluorescence microscopy is available in most life sciences research laboratories, and when optimized can be a central laboratory tool. In this chapter, the epi-fluorescence light path is introduced and the various components are discussed in detail. Recommendations are made for incident lamp light sources, excitation and emission filters, dichroic mirrors, objective lenses, and charge-coupled device (CCD) cameras in order to obtain the most sensitive epi-fluorescence microscope. The even illumination of metal-halide lamps combined with new “hard” coated filters and mirrors, a high resolution monochrome CCD camera, and a high NA objective lens are all recommended for high resolution and high sensitivity fluorescence imaging. Recommendations are also made for multicolor imaging with the use of monochrome cameras, motorized filter turrets, individual filter cubes, and corresponding dyes that are the best choice for sensitive, high resolution multicolor imaging. Images should be collected using Nyquist sampling and should be corrected for background intensity contributions and nonuniform illumination across the field of view. Photostable fluorescent probes and proteins that absorb a lot of light (i.e., high extinction co-efficients) and generate a lot of fluorescence signal (i.e., high quantum yields) are optimal. A neuronal immune-fluorescence labeling protocol is also presented. Finally, in order to maximize the utility of sensitive wide-field microscopes and generate the highest resolution images with high signal-to-noise, advice for combining wide-field epi-fluorescence imaging with restorative image deconvolution is presented. PMID:23026996

Encoding photonic angular momentum information onto surface plasmon polaritons with plasmonic lens.

PubMed

Liu, Aiping; Rui, Guanghao; Ren, Xifeng; Zhan, Qiwen; Guo, Guangcan; Guo, Guoping

2012-10-22

Both spin angular momentum (SAM) and orbital angular momentum (OAM) can be used to carry information in classical optics and quantum optics. In this paper, the encoding of angular momentum (AM) information of photons onto surface plasmon polaritons (SPPs) is demonstrated using a nano-ring plasmonic lens. Near-field energy distribution on the metal surface is measured using a near-field scanning optical microscope (NSOM) when the plasmonic lens is excited by photons with different combinations of SAM and OAM. It is found that both the SAM and OAM can influence the near field energy distribution of SPPs. More interestingly, numerical and experimental studies reveal that the energy distribution on the plasmonic lens surface is determined by the absolute value of the total AM. This gives direct evidences that SPPs can be encoded with the photonic SAM and OAM information simultaneously and the spin degeneracy of the photons can be removed using the interactions between photonic OAM and plasmonic lens. The findings are useful not only for the fundamental understanding of the photonic AM but also for the future design of plasmonic quantum optics devices and systems.

An ultrahigh vacuum multipurpose specimen chamber with sample introduction system for in situ transmission electron microscopy investigations

NASA Technical Reports Server (NTRS)

Heinemann, K.; Poppa, H.

1986-01-01

A commercial transmission electron microscope (TEM), with flat-plate upper pole piece configuration of the objective lens, and top-entry specimen introduction was modified by introducing an ultrahigh vacuum (UHV) specimen chamber for in situ TEM experimentation. The pumping and design principles and special features of this UHV chamber, which makes it possible to obtain 5 x 10 to the -10th mbar pressure at the site of the specimen, while maintaining the airlock system that allows operation in the 10 to the -10th mbar range within 15 min after specimen change, are described. Design operating pressures and image quality (resolution of metal particles smaller than 1 nm in size) were achieved. Schematic drawings and design dimensions are included.

Non-contact quantification of laser micro-impulse in water by atomic force microscopy and its application for biomechanics

NASA Astrophysics Data System (ADS)

Hosokawa, Yoichiroh

2011-12-01

We developed a local force measurement system of a femtosecond laser-induced impulsive force, which is due to shock and stress waves generated by focusing an intense femtosecond laser into water with a highly numerical aperture objective lens. In this system, the force localized in micron-sized region was detected by bending movement of a cantilever of atomic force microscope (AFM). Here we calculated the bending movement of the AFM cantilever when the femtosecond laser is focused in water at the vicinity of the cantilever and the impulsive force is loaded on the cantilever. From the result, a method to estimate the total of the impulsive force at the laser focal point was suggested and applied to estimate intercellular adhesion strength.

Active liquid-crystal deflector and lens with Fresnel structure

NASA Astrophysics Data System (ADS)

Shibuya, Giichi; Yamano, Shohei; Yoshida, Hiroyuki; Ozaki, Masanori

2017-02-01

A new type of tunable Fresnel deflector and lens composed of liquid crystal was developed. Combined structure of multiple interdigitated electrodes and the high-resistivity (HR) layer implements the saw-tooth distribution of electrical potential with only the planar surfaces of the transparent substrates. According to the numerical calculation and design, experimental devices were manufactured with the liquid crystal (LC) material sealed into the sandwiched flat glass plates of 0.7 mm thickness with rubbed alignment layers set to an anti-parallel configuration. Fabricated beam deflector with no moving parts shows the maximum tilt angle of +/-1.3 deg which can apply for optical image stabilizer (OIS) of micro camera. We also discussed and verified their lens characteristics to be extended more advanced applications. Transparent interdigitated electrodes were concentrically aligned on the lens aperture with the insulator gaps under their boundary area. The diameter of the lens aperture was 30 mm and the total number of Fresnel zone was 100. Phase retardation of the beam wavefront irradiated from the LC lens device can be evaluated by polarizing microscope images with a monochromatic filter. Radial positions of each observed fringe are plotted and fitted with 2nd degree polynomial approximation. The number of appeared fringes is over 600 in whole lens aperture area and the correlation coefficients of all approximations are over 0.993 that seems enough ideal optical wavefront. The obtained maximum lens powers from the approximations are about +/-4 m-1 which was satisfied both convex and concave lens characteristics; and their practical use for the tunable lens grade eyeglasses became more prospective.

Reflections From a Fresnel Lens

ERIC Educational Resources Information Center

Keeports, David

2005-01-01

Reflection of light by a convex Fresnel lens gives rise to two distinct images. A highly convex inverted real reflective image forms on the object side of the lens, while an upright virtual reflective image forms on the opposite side of the lens. I describe here a set of laser experiments performed upon a Fresnel lens. These experiments provide…

Fiber optical tweezers for microscale and nanoscale particle manipulation and force sensing

NASA Astrophysics Data System (ADS)

Liu, Yuxiang

2011-12-01

Optical tweezers have been an important tool in biology and physics for studying single molecules and colloidal systems. Most of current optical tweezers are built with microscope objectives, which are: i) expensive, ii) bulky and hard to integrate, iii) sensitive to environmental fluctuations, iv) limited in terms of working distances from the substrate, and v) rigid with the requirements on the substrate (transparent substrate made with glass and with a fixed thickness). These limitations of objective-based optical tweezers prevent them from being miniaturized. Fiber optical tweezers can provide a solution for cost reduction and miniaturization, and these optical tweezers can be potentially used in microfluidic systems. However, the existing fiber optical tweezers have the following limitations: i) low trapping efficiency due to weakly focused beams, ii) lack of the ability to control the positions of multiple particles simultaneously, and iii) limited functionalities. The overall objective of this dissertation work is to further the fundamental understanding of fiber optical tweezers through experimental study and modeling, and to develop novel fiber optical tweezers systems to enhance the capability and functionalities of fiber optical tweezers as microscale and nanoscale manipulators/sensors. The contributions of this dissertation work are summarized as follows. i) An enhanced understanding of the inclined dual-fiber optical tweezers (DFOTs) system has been achieved. Stable three dimensional (3D) optical trapping of a single micron-sized particle has been experimentally demonstrated. This is the first time that the trapping efficiency has been calibrated and the stiffness of the trap has been obtained in the experiments, which has been carried out by using two methods: the drag force method and power spectrum analysis. Such calibration enables the system to be used as a picoNewton-level force sensor in addition to a particle manipulator. The influence of system parameters on the trapping performance has been carefully investigated through both experimental and numerical studies. ii) Multiple traps have been created and carefully studied with the inclined DFOTs for the first time. Three traps, one 3D trap and two 2D traps, have been experimentally created at different vertical levels with adjustable separations and positions. iii) Multiple functionalities have been achieved and studied for the first time with the inclined DFOTs. Particle separation, grouping, stacking, rod alignment, rod rotation, and optical binding have been experimentally demonstrated. The multiple functionalities allow the inclined DFOTs to find applications in the study of interaction forces in colloidal systems as well as parallel particle manipulation in drug delivery systems. iv) Far-field superfocusing effect has been investigated and successfully demonstrated with a fiber-based surface plasmonic (SP) lens for the first time. A planar SP lens with a set of concentric nanoscale rings on a fiber endface has been developed. For the first time, a focus size that is comparable to the smallest achievable focus size of high NA objective lenses has been achieved with the fiber-based SP lens. The fiber-based SP lens can bridge the nanoscale particles/systems and the macroscale power sources/detectors, which has been a long standing challenge for nanophotonics. In addition to optical trapping, the fiber-based SP lens will impact many applications including high-resolution lithography, high-resolution fluorescence detection, and sub-wavelength imaging. v) Trapping ability enhanced with the fiber-based SP lens has been successfully demonstrated. With the help of the fiber-based SP lens, the trapping efficiency of fiber optical tweezers has been significantly enhanced, which is comparable with that of objective-based optical tweezers. A submicron-sized bacterium has been successfully trapped in three dimensions for the first time with optical tweezers based on single fibers.

Hartmann characterization of the PEEM-3 aberration-corrected X-ray photoemission electron microscope.

PubMed

Scholl, A; Marcus, M A; Doran, A; Nasiatka, J R; Young, A T; MacDowell, A A; Streubel, R; Kent, N; Feng, J; Wan, W; Padmore, H A

2018-05-01

Aberration correction by an electron mirror dramatically improves the spatial resolution and transmission of photoemission electron microscopes. We will review the performance of the recently installed aberration corrector of the X-ray Photoemission Electron Microscope PEEM-3 and show a large improvement in the efficiency of the electron optics. Hartmann testing is introduced as a quantitative method to measure the geometrical aberrations of a cathode lens electron microscope. We find that aberration correction leads to an order of magnitude reduction of the spherical aberrations, suggesting that a spatial resolution of below 100 nm is possible at 100% transmission of the optics when using x-rays. We demonstrate this improved performance by imaging test patterns employing element and magnetic contrast. Published by Elsevier B.V.

Scanning laser microscope for imaging nanostructured superconductors

NASA Astrophysics Data System (ADS)

Ishida, Takekazu; Arai, Kohei; Akita, Yukio; Miyanari, Mitsunori; Minami, Yusuke; Yotsuya, Tsutomu; Kato, Masaru; Satoh, Kazuo; Uno, Mayumi; Shimakage, Hisashi; Miki, Shigehito; Wang, Zhen

2010-10-01

The nanofabrication of superconductors yields various interesting features in superconducting properties. A variety of different imaging techniques have been developed for probing the local superconducting profiles. A scanning pulsed laser microscope has been developed by the combination of the XYZ piezo-driven stages and an optical fiber with an aspheric focusing lens. The scanning laser microscope is used to understand the position-dependent properties of a superconducting MgB 2 stripline of length 100 μm and width of 3 μm under constant bias current. Our results show that the superconducting stripline can clearly be seen in the contour image of the scanning laser microscope on the signal voltage. It is suggested from the observed image that the inhomogeneity is relevant in specifying the operating conditions such as detection efficiency of the sensor.

Optimising electron microscopy experiment through electron optics simulation.

PubMed

Kubo, Y; Gatel, C; Snoeck, E; Houdellier, F

2017-04-01

We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e. the field emission (FE) cathode, the extraction optic and acceleration stages of a 300kV cold field emission gun, the illumination lenses, the objective lens, the intermediate and projection lenses. Full trajectories can be computed using magnetically saturated or non-saturated round lenses, magnetic deflectors and even non-cylindrical symmetry elements like electrostatic biprism. This multi-scale model gathers nanometer size components (FE tip) with parts of meter length (illumination and projection systems). We demonstrate that non-trivial TEM experiments requiring specific and complex optical configurations can be simulated and optimized prior to any experiment using such model. We show that all the currents set in all optical elements of the simulated column can be implemented in the real column (I2TEM in CEMES) and used as starting alignment for the requested experiment. We argue that the combination of such complete electron trajectory simulations in the whole TEM column with automatic optimization of the microscope parameters for optimal experimental data (images, diffraction, spectra) allows drastically simplifying the implementation of complex experiments in TEM and will facilitate the development of advanced use of the electron microscope in the near future. Copyright © 2017 Elsevier B.V. All rights reserved.

Diffraction limited focusing and routing of gap plasmons by a metal-dielectric-metal lens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dennis, Brian S.; Czaplewski, David A.; Haftel, Michael I.

2015-01-01

Passive optical elements can play key roles in photonic applications such as plasmonic integrated circuits. Here we experimentally demonstrate passive gap-plasmon focusing and routing in two-dimensions. This is accomplished using a high numerical-aperture metal-dielectric-metal lens incorporated into a planar-waveguide device. Fabrication via metal sputtering, oxide deposition, electron-and focused-ion-beam lithography, and argon ion-milling is reported on in detail. Diffraction-limited focusing is optically characterized by sampling out-coupled light with a microscope. The measured focal distance and full-width-half-maximum spot size agree well with the calculated lens performance. The surface plasmon polariton propagation length is measured by sampling light from multiple out-coupler slits. (C)more » 2015 Optical Society of America« less

Evaluation of the Dark-Medium Objective Lens in Counting Asbestos Fibers by Phase-Contrast Microscopy

PubMed Central

Lee, Eun Gyung; Nelson, John H.; Kashon, Michael L.; Harper, Martin

2015-01-01

A Japanese round-robin study revealed that analysts who used a dark-medium (DM) objective lens reported higher fiber counts from American Industrial Hygiene Association (AIHA) Proficiency Analytical Testing (PAT) chrysotile samples than those using a standard objective lens, but the cause of this difference was not investigated at that time. The purpose of this study is to determine any major source of this difference by performing two sets of round-robin studies. For the first round-robin study, 15 AIHA PAT samples (five each of chrysotile and amosite generated by water-suspended method, and five chrysotile generated by aerosolization method) were prepared with relocatable cover slips and examined by nine laboratories. A second round-robin study was then performed with six chrysotile field sample slides by six out of nine laboratories who participated in the first round-robin study. In addition, two phase-shift test slides to check analysts’ visibility and an eight-form diatom test plate to compare resolution between the two objectives were examined. For the AIHA PAT chrysotile reference slides, use of the DM objective resulted in consistently higher fiber counts (1.45 times for all data) than the standard objective (P-value < 0.05), regardless of the filter generation (water-suspension or aerosol) method. For the AIHA PAT amosite reference and chrysotile field sample slides, the fiber counts between the two objectives were not significantly different. No statistically significant differences were observed in the visibility of blocks of the test slides between the two objectives. Also, the DM and standard objectives showed no pattern of differences in viewing the fine lines and/or dots of each species images on the eight-form diatom test plate. Among various potential factors that might affect the analysts’ performance of fiber counts, this study supports the greater contrast caused by the different phase plate absorptions as the main cause of high counts for the AIHA PAT chrysotile slides using the DM objective. The comparison of fiber count ratios (DM/standard) between the AIHA PAT chrysotile samples and chrysotile field samples indicates that there is a fraction of fibers in the PAT samples approaching the theoretical limit of visibility of the phase-contrast microscope with 3-degree phase-shift. These fibers become more clearly visible through the greater contrast from the phase plate absorption of the DM objective. However, as such fibers are not present in field samples, no difference in counts between the two objectives was observed in this study. The DM objective, therefore, could be allowed for routine fiber counting as it will maintain continuity with risk assessments based on earlier phase-contrast microscopy fiber counts from field samples. Published standard methods would need to be modified to allow a higher aperture specification for the objective. PMID:25737333

Portable biochip scanner device

DOEpatents

Perov, Alexander; Sharonov, Alexei; Mirzabekov, Andrei D.

2002-01-01

A portable biochip scanner device used to detect and acquire fluorescence signal data from biological microchips (biochips) is provided. The portable biochip scanner device employs a laser for emitting an excitation beam. An optical fiber delivers the laser beam to a portable biochip scanner. A lens collimates the laser beam, the collimated laser beam is deflected by a dichroic mirror and focused by an objective lens onto a biochip. The fluorescence light from the biochip is collected and collimated by the objective lens. The fluorescence light is delivered to a photomultiplier tube (PMT) via an emission filter and a focusing lens. The focusing lens focuses the fluorescence light into a pinhole. A signal output of the PMT is processed and displayed.

Coherent x-ray zoom condenser lens for diffractive and scanning microscopy.

PubMed

Kimura, Takashi; Matsuyama, Satoshi; Yamauchi, Kazuto; Nishino, Yoshinori

2013-04-22

We propose a coherent x-ray zoom condenser lens composed of two-stage deformable Kirkpatrick-Baez mirrors. The lens delivers coherent x-rays with a controllable beam size, from one micrometer to a few tens of nanometers, at a fixed focal position. The lens is suitable for diffractive and scanning microscopy. We also propose non-scanning coherent diffraction microscopy for extended objects by using an apodized focused beam produced by the lens with a spatial filter. The proposed apodized-illumination method will be useful in highly efficient imaging with ultimate storage ring sources, and will also open the way to single-shot coherent diffraction microscopy of extended objects with x-ray free-electron lasers.

Multipurpose Hyperspectral Imaging System

NASA Technical Reports Server (NTRS)

Mao, Chengye; Smith, David; Lanoue, Mark A.; Poole, Gavin H.; Heitschmidt, Jerry; Martinez, Luis; Windham, William A.; Lawrence, Kurt C.; Park, Bosoon

2005-01-01

A hyperspectral imaging system of high spectral and spatial resolution that incorporates several innovative features has been developed to incorporate a focal plane scanner (U.S. Patent 6,166,373). This feature enables the system to be used for both airborne/spaceborne and laboratory hyperspectral imaging with or without relative movement of the imaging system, and it can be used to scan a target of any size as long as the target can be imaged at the focal plane; for example, automated inspection of food items and identification of single-celled organisms. The spectral resolution of this system is greater than that of prior terrestrial multispectral imaging systems. Moreover, unlike prior high-spectral resolution airborne and spaceborne hyperspectral imaging systems, this system does not rely on relative movement of the target and the imaging system to sweep an imaging line across a scene. This compact system (see figure) consists of a front objective mounted at a translation stage with a motorized actuator, and a line-slit imaging spectrograph mounted within a rotary assembly with a rear adaptor to a charged-coupled-device (CCD) camera. Push-broom scanning is carried out by the motorized actuator which can be controlled either manually by an operator or automatically by a computer to drive the line-slit across an image at a focal plane of the front objective. To reduce the cost, the system has been designed to integrate as many as possible off-the-shelf components including the CCD camera and spectrograph. The system has achieved high spectral and spatial resolutions by using a high-quality CCD camera, spectrograph, and front objective lens. Fixtures for attachment of the system to a microscope (U.S. Patent 6,495,818 B1) make it possible to acquire multispectral images of single cells and other microscopic objects.

Failure of molecular diagnostics of a keratitis-inducing Acanthamoeba strain.

PubMed

Scheid, Patrick L; Balczun, Carsten

2017-12-01

An otherwise healthy 49-year-old female patient presented at the local hospital with severe keratitis in both inflamed eyes. She was a contact lens wearer and had no history of a corneal trauma. In our laboratory for medical parasitology Acanthamoebae were detected microscopically from the cornea scraping and from the fluid of the contact lens storage case after xenical culture and showed the typical cyst morphology of Acanthamoebae group II. The diagnosis of "Acanthamoeba keratitis" was established and successful therapy was provided. While the morphological microscopic method led to the correct diagnosis in this case, an in-house multiplex qPCR and a commercial qPCR showed false negative results regarding Acanthamoeba sp. The subsequent sequencing revealed the Acanthamoeba genotype T4. In the present case report, the inability to detect Acanthamoebae using qPCR only is presented. Therefore, we recommend the utilization of combined different assays for optimal diagnostic purposes. Copyright © 2017 Elsevier Inc. All rights reserved.

An infrared modular panoramic imaging objective

NASA Astrophysics Data System (ADS)

Palmer, Troy A.; Alexay, Christopher C.

2004-08-01

We describe the optical and mechanical design of an athermal infrared objective lens with an afocal anamorphic adapter. The lens presented consists of two modules: an athermal 25mm F/2.3 mid-wave IR objective lens and an optional panoramic adapter. The adapter utilizes anamorphic lenses to create unique image control. The result of which enables an independent horizontal wide field of view, while preserving the original narrow vertical field. We have designed, fabricated and tested two such lenses. A summary of the assembly and testing process is also presented.

Single-shot measurement of phase and amplitude by using a heterodyne time-lens system and ultrafast digital time-holography

NASA Astrophysics Data System (ADS)

Tikan, Alexey; Bielawski, Serge; Szwaj, Christophe; Randoux, Stéphane; Suret, Pierre

2018-04-01

Temporal imaging systems are outstanding tools for single-shot observation of optical signals that have irregular and ultrafast dynamics. They allow long time windows to be recorded with femtosecond resolution, and do not rely on complex algorithms. However, simultaneous recording of amplitude and phase remains an open challenge for these systems. Here, we present a new heterodyne time-lens arrangement that efficiently records both the amplitude and phase of complex and random signals over large temporal windows (tens of picoseconds). Phase and time are encoded onto the two spatial dimensions of a camera. We implement this phase-sensitive time-lens system in two configurations: a time microscope and a digital temporal-holography device that enables single-shot measurement with a temporal resolution of 80 fs. We demonstrate direct application of our heterodyne time-lens to turbulent-like optical fields and optical rogue waves generated from nonlinear propagation of partially coherent waves inside optical fibres.

Dynamic metasurface lens based on MEMS technology

NASA Astrophysics Data System (ADS)

Roy, Tapashree; Zhang, Shuyan; Jung, Il Woong; Troccoli, Mariano; Capasso, Federico; Lopez, Daniel

2018-02-01

In the recent years, metasurfaces, being flat and lightweight, have been designed to replace bulky optical components with various functions. We demonstrate a monolithic Micro-Electro-Mechanical System (MEMS) integrated with a metasurface-based flat lens that focuses light in the mid-infrared spectrum. A two-dimensional scanning MEMS platform controls the angle of the lens along two orthogonal axes by ±9°, thus enabling dynamic beam steering. The device could be used to compensate for off-axis incident light and thus correct for aberrations such as coma. We show that for low angular displacements, the integrated lens-on-MEMS system does not affect the mechanical performance of the MEMS actuators and preserves the focused beam profile as well as the measured full width at half maximum. We envision a new class of flat optical devices with active control provided by the combination of metasurfaces and MEMS for a wide range of applications, such as miniaturized MEMS-based microscope systems, LIDAR scanners, and projection systems.

Aberration corrected 1.2-MV cold field-emission transmission electron microscope with a sub-50-pm resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akashi, Tetsuya; Takahashi, Yoshio; Tanigaki, Toshiaki, E-mail: toshiaki.tanigaki.mv@hitachi.com

2015-02-16

Atomic-resolution electromagnetic field observation is critical to the development of advanced materials and to the unveiling of their fundamental physics. For this purpose, a spherical-aberration corrected 1.2-MV cold field-emission transmission electron microscope has been developed. The microscope has the following superior properties: stabilized accelerating voltage, minimized electrical and mechanical fluctuation, and coherent electron emission. These properties have enabled to obtain 43-pm information transfer. On the bases of these performances, a 43-pm resolution has been obtained by correcting lens aberrations up to the third order. Observations of GaN [411] thin crystal showed a projected atomic locations with a separation of 44 pm.

Thermal diffusivity imaging with the thermal lens microscope.

PubMed

Dada, Oluwatosin O; Feist, Peter E; Dovichi, Norman J

2011-12-01

A coaxial thermal lens microscope was used to generate images based on both the absorbance and thermal diffusivity of histological samples. A pump beam was modulated at frequencies ranging from 50 kHz to 5 MHz using an acousto-optic modulator. The pump and a CW probe beam were combined with a dichroic mirror, directed into an inverted microscope, and focused onto the specimen. The change in the transmitted probe beam's center intensity was detected with a photodiode. The photodiode's signal and a reference signal from the modulator were sent to a high-speed lock-in amplifier. The in-phase and quadrature signals were recorded as a sample was translated through the focused beams and used to generate images based on the amplitude and phase of the lock-in amplifier's signal. The amplitude is related to the absorbance and the phase is related to the thermal diffusivity of the sample. Thin sections of stained liver and bone tissues were imaged; the contrast and signal-to-noise ratio of the phase image was highest at frequencies from 0.1-1 MHz and dropped at higher frequencies. The spatial resolution was 2.5 μm for both amplitude and phase images, limited by the pump beam spot size. © 2011 Optical Society of America

Silicone intraocular lens surface calcification in a patient with asteroid hyalosis.

PubMed

Matsumura, Kazuhiro; Takano, Masahiko; Shimizu, Kimiya; Nemoto, Noriko

2012-07-01

To confirm a substance presence on the posterior intraocular lens (IOL) surface in a patient with asteroid hyalosis. An 80-year-old man had IOLs for approximately 12 years. Opacities and neodymium-doped yttrium aluminum garnet pits were observed on the posterior surface of the right IOL. Asteroid hyalosis and an epiretinal membrane were observed OD. An IOL exchange was performed on 24 March 2008, and the explanted IOL was analyzed using a light microscope and a transmission electron microscope with a scanning electron micrograph and an energy-dispersive X-ray spectrometer for elemental analysis. To confirm asteroid hyalosis, asteroid bodies were examined with the ionic liquid (EtMeIm+ BF4-) method using a field emission scanning electron microscope (FE-SEM) with digital beam control RGB mapping. X-ray spectrometry of the deposits revealed high calcium and phosphorus peaks. Spectrometry revealed that the posterior IOL surface opacity was due to a calcium-phosphorus compound. Examination of the asteroid bodies using FE-SEM with digital beam control RGB mapping confirmed calcium and phosphorus as the main components. Calcium hydrogen phosphate dihydrate deposits were probably responsible for the posterior IOL surface opacity. Furthermore, analysis of the asteroid bodies demonstrated that calcium and phosphorus were its main components.

New optical architecture for holographic data storage system compatible with Blu-ray Disc™ system

NASA Astrophysics Data System (ADS)

Shimada, Ken-ichi; Ide, Tatsuro; Shimano, Takeshi; Anderson, Ken; Curtis, Kevin

2014-02-01

A new optical architecture for holographic data storage system which is compatible with a Blu-ray Disc™ (BD) system is proposed. In the architecture, both signal and reference beams pass through a single objective lens with numerical aperture (NA) 0.85 for realizing angularly multiplexed recording. The geometry of the architecture brings a high affinity with an optical architecture in the BD system because the objective lens can be placed parallel to a holographic medium. Through the comparison of experimental results with theory, the validity of the optical architecture was verified and demonstrated that the conventional objective lens motion technique in the BD system is available for angularly multiplexed recording. The test-bed composed of a blue laser system and an objective lens of the NA 0.85 was designed. The feasibility of its compatibility with BD is examined through the designed test-bed.

Template Synthesis and Magnetic Manipulation of Nickel Nanowires

ERIC Educational Resources Information Center

Bentley, Anne K.; Crone, Wendy C.; Farhoud, Mohammed; Ellis, Arthur B.; Lisensky, George C.; Nickel, Anne-Marie L.

2005-01-01

An experiment that highlights the role electrochemistry plays in the fabrication of nanoscale structures is presented. The movement and alignment of the nickel nanowires were observed, when manipulated using magnetic fields through the lens of an optical microscope using common magnets to alter the applied magnetic field.

Design of Magnetic Charged Particle Lens Using Analytical Potential Formula

NASA Astrophysics Data System (ADS)

Al-Batat, A. H.; Yaseen, M. J.; Abbas, S. R.; Al-Amshani, M. S.; Hasan, H. S.

2018-05-01

In the current research was to benefit from the potential of the two cylindrical electric lenses to be used in the product a mathematical model from which, one can determine the magnetic field distribution of the charged particle objective lens. With aid of simulink in matlab environment, some simulink models have been building to determine the distribution of the target function and their related axial functions along the optical axis of the charged particle lens. The present study showed that the physical parameters (i.e., the maximum value, Bmax, and the half width W of the field distribution) and the objective properties of the charged particle lens have been affected by varying the main geometrical parameter of the lens named the bore radius R.

The influence of end of day silicone hydrogel daily disposable contact lens fit on ocular comfort, physiology and lens wettability.

PubMed

Wolffsohn, James; Hall, Lee; Mroczkowska, Stephanie; Hunt, Olivia A; Bilkhu, Paramdeep; Drew, Tom; Sheppard, Amy

2015-10-01

To quantify the end-of-day silicone-hydrogel daily disposable contact lens fit and its influence of on ocular comfort, physiology and lens wettability. Thirty-nine subjects (22.1±3.5 years) were randomised to wear each of 3 silicone-hydrogel daily-disposable contact lenses (narafilcon A, delefilcon A and filcon II 3), bilaterally, for one week. Lens fit was assessed objectively using a digital video slit-lamp at 8, 12 and 16h after lens insertion. Hyperaemia, non-invasive tear break-up time, tear meniscus height and comfort were also evaluated at these timepoints, while corneal and conjunctival staining were assessed on lens removal. Lens fit assessments were not different between brands (P>0.05), with the exception of the movement at blink where narafilcon A was more mobile. Overall, lag reduced but push-up speed increased from 8 to 12h (P<0.05), but remained stable from 12 to 16h (P>0.05). Movement-on-blink was unaffected by wear-time (F=0.403, P=0.670). A more mobile lens fit with one brand did not indicate that person would have a more mobile fit with another brand (r=-0.06 to 0.63). Lens fit was not correlated with comfort, ocular physiology or lens wettability (P>0.01). Among the lenses tested, objective lens fit changed between 8h and 12h of lens wear. The weak correlation in individual lens fit between brands indicates that fit is dependent on more than ocular shape. Consequently, substitution of a different lens brand with similar parameters will not necessarily provide comparable lens fit. Copyright © 2015 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Optoelectronic tweezers integrated with lensfree holographic microscopy for wide-field interactive cell and particle manipulation on a chip.

PubMed

Huang, Kuo-Wei; Su, Ting-Wei; Ozcan, Aydogan; Chiou, Pei-Yu

2013-06-21

We demonstrate an optoelectronic tweezer (OET) coupled to a lensfree holographic microscope for real-time interactive manipulation of cells and micro-particles over a large field-of-view (FOV). This integrated platform can record the holographic images of cells and particles over the entire active area of a CCD sensor array, perform digital image reconstruction to identify target cells, dynamically track the positions of cells and particles, and project light beams to trigger light-induced dielectrophoretic forces to pattern and sort cells on a chip. OET technology has been previously shown to be capable of performing parallel single cell manipulation over a large area. However, its throughput has been bottlenecked by the number of cells that can be imaged within the limited FOV of a conventional microscope objective lens. Integrating lensfree holographic imaging with OET solves this fundamental FOV barrier, while also creating a compact on-chip cell/particle manipulation platform. Using this unique platform, we have successfully demonstrated real-time interactive manipulation of thousands of single cells and micro-particles over an ultra-large area of e.g., 240 mm(2) (i.e. 17.96 mm × 13.52 mm).

Boundary-artifact-free phase retrieval with the transport of intensity equation II: applications to microlens characterization.

PubMed

Zuo, Chao; Chen, Qian; Li, Hongru; Qu, Weijuan; Asundi, Anand

2014-07-28

Boundary conditions play a crucial role in the solution of the transport of intensity equation (TIE). If not appropriately handled, they can create significant boundary artifacts across the reconstruction result. In a previous paper [Opt. Express 22, 9220 (2014)], we presented a new boundary-artifact-free TIE phase retrieval method with use of discrete cosine transform (DCT). Here we report its experimental investigations with applications to the micro-optics characterization. The experimental setup is based on a tunable lens based 4f system attached to a non-modified inverted bright-field microscope. We establish inhomogeneous Neumann boundary values by placing a rectangular aperture in the intermediate image plane of the microscope. Then the boundary values are applied to solve the TIE with our DCT-based TIE solver. Experimental results on microlenses highlight the importance of boundary conditions that often overlooked in simplified models, and confirm that our approach effectively avoid the boundary error even when objects are located at the image borders. It is further demonstrated that our technique is non-interferometric, accurate, fast, full-field, and flexible, rendering it a promising metrological tool for the micro-optics inspection.

High resolution 3D confocal microscope imaging of volcanic ash particles.

PubMed

Wertheim, David; Gillmore, Gavin; Gill, Ian; Petford, Nick

2017-07-15

We present initial results from a novel high resolution confocal microscopy study of the 3D surface structure of volcanic ash particles from two recent explosive basaltic eruptions, Eyjafjallajökull (2010) and Grimsvötn (2011), in Iceland. The majority of particles imaged are less than 100μm in size and include PM 10 s, known to be harmful to humans if inhaled. Previous studies have mainly used 2D microscopy to examine volcanic particles. The aim of this study was to test the potential of 3D laser scanning confocal microscopy as a reliable analysis tool for these materials and if so to what degree high resolution surface and volume data could be obtained that would further aid in their classification. First results obtained using an Olympus LEXT scanning confocal microscope with a ×50 and ×100 objective lens are highly encouraging. They reveal a range of discrete particle types characterised by sharp or concave edges consistent with explosive formation and sudden rupture of magma. Initial surface area/volume ratios are given that may prove useful in subsequent modelling of damage to aircraft engines and human tissue where inhalation has occurred. Copyright © 2017 Elsevier B.V. All rights reserved.

Time-Resolved, High-Resolution, X-Ray Microscopy of In-Vitro Biological and Life Science Specimens with the Aid of Laser Plasmas

DTIC Science & Technology

1994-06-30

transmissive Fresnel lens. We have made considerable effort in the last few years to explore the potential of x-ray multilayer-coated Schwarzschild x-ray...ray mirror fabrication and efficient x-ray mirror design. A 120mm diameter, NA = 0.35, 15X Schwarzschild microscope coated with Ni/C multilayer mios for...et al 2 developed a smaller, 33mm diameter, NA - 0.28, 15X Schwarzschild microscope coated with a W/C multilayer mirror for 4.4nm, in the socalled

Microlenses and microcameras for biomedical imaging

NASA Astrophysics Data System (ADS)

Kanhere, Aditi

Liquid lens technology is a rapidly progressing field driven by the promise of low cost fabrication, faster response, fewer mechanical elements, versatility and ease of customization for different applications. Here we present the use of liquid lenses for biomedical optics and medical imaging. I will specifically focus on our approaches towards the development of two liquid-lens optical systems -- laparoscopic cameras and 3D microscopy. The first part of this work is based on the development of a multi-camera laparoscopic imaging system with tunable focusing capability. The work attempts to find a solution to overcome many of the fundamental challenges faced by current laparoscopic imaging systems. The system is developed upon the key idea that widely spread multiple, tunable microcameras can cover a large range of vantage points and field of view (FoV) for intra-abdominal visualization. Our design features multiple tunable-focus microcameras integrated with a surgical port to provide panoramic intra-abdominal visualization with enhanced depth perception. Our system can be optically tuned to focus in on objects within a range of 5 mm to infinity, with a FoV adjustable between 36 degrees and 130 degrees. This unique approach also eliminates the requirement of an exclusive imaging port and need for navigation of cameras between ports during surgery. The second part of this report focuses on the application of tunable lenses in microscopy. Conventional wide-field microscopy is one of the most widely used optical microscopy technique. This technique typically captures a two dimensional image of a specimen. For a volumetric visualization of the sample or to enable depth scanning along the axial direction, it is necessary to move the sample relative to the fixed focal plane of the microscope objective. For this purpose, a mechanical z-scanning stage is typically employed. The stage enables the focal plane to move through the sample. Typical approaches used to achieve axial scanning are a motorized stepper stage or a piezoelectric stage. While stepper motors offer the advantage of unlimited travel distance, they suffer from hysteresis. Piezoelectric stages on the other hand, help eliminate hysteresis at the cost of the travel distance which is reduced to 100-200 mum. Both the types of stages, however, are bulky and cause vibrations and wobble in the sample due to high inertia. Additional care is required to avoid mechanical overshoots and backlash from the tip touching the sample. Additionally, for water or oil-immersion lenses, vibration of the sample stage can cause disturbance or ripples in the immersion media that can lead to significant distortion in the images. A robust alternative to the use of mechanical scanning stages is a remote focusing system that allows both the objective and the sample to be stationary. One such solution is the employment of a tunable-focus liquid lens in conjunction with a microscope objective to achieve axial scanning through a sample being imaged. Our work demonstrates the implementation of a robust, cost-effective and energy-efficient axial tuning solution for 3D microscopy based on thermo-responsive hydrogel-based tunable liquid lenses.

Large aperture diffractive space telescope

DOEpatents

Hyde, Roderick A.

2001-01-01

A large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary objective lens functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass "aiming" at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The objective lens includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the objective lens, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets which may be either earth bound or celestial.

Imaging objects behind small obstacles using axicon lens

NASA Astrophysics Data System (ADS)

Perinchery, Sandeep M.; Shinde, Anant; Murukeshan, V. M.

2017-06-01

Axicon lenses are conical prisms, which are known to focus a light source to a line comprising of multiple points along the optical axis. In this study, we analyze the potential of axicon lenses to view, image and record the object behind opaque obstacles in free space. The advantage of an axicon lens over a regular lens is demonstrated experimentally. Parameters such as obstacle size, object and the obstacle position in the context of imaging behind obstacles are tested using Zemax optical simulation. This proposed concept can be easily adapted to most of the optical imaging methods and microscopy modalities.

Coherent diffraction imaging by moving a lens.

PubMed

Shen, Cheng; Tan, Jiubin; Wei, Ce; Liu, Zhengjun

2016-07-25

A moveable lens is used for determining amplitude and phase on the object plane. The extended fractional Fourier transform is introduced to address the single lens imaging. We put forward a fast algorithm for the transform by convolution. Combined with parallel iterative phase retrieval algorithm, it is applied to reconstruct the complex amplitude of the object. Compared with inline holography, the implementation of our method is simple and easy. Without the oversampling operation, the computational load is less. Also the proposed method has a superiority of accuracy over the direct focusing measurement for the imaging of small size objects.

Cow's Eye Dissection in the Physics Lab.

ERIC Educational Resources Information Center

Lapp, David R.; Keenan, James E.

1991-01-01

Proposes the science demonstration of dissecting a cow's eye to integrate biology and physics in the study of optics and lenses. Reviews the anatomy of the eye, describes the visual process and covers topics as index of refraction of the cornea, microscopic receptors, the lens, and the retina. (MDH)

Direct fabrication of silicone lenses with 3D printed parts

NASA Astrophysics Data System (ADS)

Kamal, Tahseen; Watkins, Rachel; Cen, Zijian; Lee, W. M.

2016-11-01

The traditional process of making glass lenses requires grinding and polishing of the material which is a tedious and sensitive process. Existing polymer lens making techniques, such as high temperature reflow techniques, have been significantly simple lens making processes which cater well to customer industry. Recently, the use of UV-curing liquid lens has ushered in customized lens making (Printed Optics), but contains undesirable yellowing effects. Polydimethylsiloxane (PDMS) is a transparent polymer curable at low temperature (<100°C) provides an alternative to lens making. In this work, we showed that PDMS lenses are fabricated using single silicone droplets which are formed in a guided and controlled passive manner using 3D printed tools. These silicone lenses have attributes such as smoothness of curvature, resilience to temperature change, low optical aberrations, high transparency (>95%) and minimal aging (yellowing). Moreover, these lenses have a range of focal lengths (3.5 mm to 14.5 mm as well as magnifications (up to 160X). In addition, we created smartphone attachment to turn smart device (tablet or smartphone) into a low-powered microscope. In future we plan to extend this method to produce microlens array.

Holographic fluorescence mapping using space-division matching method

NASA Astrophysics Data System (ADS)

Abe, Ryosuke; Hayasaki, Yoshio

2017-10-01

Three-dimensional mapping of fluorescence light sources was performed by using self-interference digital holography. The positions of the sources were quantitatively determined by using Gaussian fitting of the axial and lateral intensity distributions obtained from diffraction calculations through position calibration from the observation space to the sample space. A space-division matching method was developed to perform the mapping of many fluorescence light sources, in this experiment, 500 nm fluorescent nanoparticles fixed in gelatin. A fluorescence digital holographic microscope having a 60 × objective lens with a numerical aperture of 1.25 detected 13 fluorescence light sources in a measurable region with a radius of ∼ 20 μm and a height of ∼ 5 μm. It was found that the measurable region had a conical shape resulting from the overlap between two beams.

Correcting spherical aberrations induced by an unknown medium through determination of its refractive index and thickness.

PubMed

Iwaniuk, Daniel; Rastogi, Pramod; Hack, Erwin

2011-09-26

In imaging and focusing applications, spherical aberration induces axial broadening of the point spread function (PSF). A transparent medium between lens and object of interest induces spherical aberration. We propose a method that first obtains both the physical thickness and the refractive index of the aberration inducing medium in situ by measuring the induced focal shifts for paraxial and large angle rays. Then, the fourth order angle dependence of the optical path difference inside the medium is used to correct the spherical aberration using a phase-only spatial light modulator. The obtained measurement accuracy of 3% is sufficient for a complete compensation as demonstrated in a model microscope with NA 0.3 with glass plate induced axial broadening of the PSF by a factor of 5. © 2011 Optical Society of America

Near-field optical recording based on solid immersion lens system

NASA Astrophysics Data System (ADS)

Hong, Tao; Wang, Jia; Wu, Yan; Li, Dacheng

2002-09-01

Near-field optical recording based on solid immersion lens (SIL) system has attracted great attention in the field of high-density data storage in recent years. The diffraction limited spot size in optical recording and lithography can be decreased by utilizing the SIL. The SIL near-field optical storage has advantages of high density, mass storage capacity and compatibility with many technologies well developed. We have set up a SIL near-field static recording system. The recording medium is placed on a 3-D scanning stage with the scanning range of 70×70×70μm and positioning accuracy of sub-nanometer, which will ensure the rigorous separation control in SIL system and the precision motion of the recording medium. The SIL is mounted on an inverted microscope. The focusing between long working distance objective and SIL can be monitored and observed by the CCD camera and eyes. Readout signal can be collected by a detector. Some experiments have been performed based on the SIL near-field recording system. The attempt of the near-field recording on photochromic medium has been made and the resolution improvement of the SIL has been presented. The influence factors in SIL near-field recording system are also discussed in the paper.

Three-dimensional all-dielectric metamaterial solid immersion lens for subwavelength imaging at visible frequencies

PubMed Central

Fan, Wen; Yan, Bing; Wang, Zengbo; Wu, Limin

2016-01-01

Although all-dielectric metamaterials offer a low-loss alternative to current metal-based metamaterials to manipulate light at the nanoscale and may have important applications, very few have been reported to date owing to the current nanofabrication technologies. We develop a new “nano–solid-fluid assembly” method using 15-nm TiO2 nanoparticles as building blocks to fabricate the first three-dimensional (3D) all-dielectric metamaterial at visible frequencies. Because of its optical transparency, high refractive index, and deep-subwavelength structures, this 3D all-dielectric metamaterial-based solid immersion lens (mSIL) can produce a sharp image with a super-resolution of at least 45 nm under a white-light optical microscope, significantly exceeding the classical diffraction limit and previous near-field imaging techniques. Theoretical analysis reveals that electric field enhancement can be formed between contacting TiO2 nanoparticles, which causes effective confinement and propagation of visible light at the deep-subwavelength scale. This endows the mSIL with unusual abilities to illuminate object surfaces with large-area nanoscale near-field evanescent spots and to collect and convert the evanescent information into propagating waves. Our all-dielectric metamaterial design strategy demonstrates the potential to develop low-loss nanophotonic devices at visible frequencies. PMID:27536727

On-eye breakage and recovery of mini-scleral contact lens without compromise for the ocular surface.

PubMed

Macedo-de-Araújo, Rute J; van der Worp, Eef; González-Méijome, José M

2018-06-01

To report the on-eye breakage of a mini-scleral contact lens in a healthy cornea after being hit by a speeding object, without causing any severe corneal damage. A 24-year-old Caucasian male involved in a clinical study reported the in situ breakage of a mini-scleral contact lens during motorbike maintenance. The patient reported eye redness and irritation that significantly decreased after all the pieces of the lens were recovered from the eye. Ocular examinations within 48 h showed absence of corneal damage other than superficial punctate keratitis inferiorly and no fragments of the lens were found in the conjunctival sac. The patient was wearing a 15.2 mm mini-scleral lens in a high Dk material. The evolution of rigid materials towards higher Dk values has resulted in a decreased hardness and modulus values, so these materials are more elastic when subjected to mechanical stress, which could be a beneficial aspect in absorbing the energy of an impact before breaking in pieces. This case report shows that ScCL could have a protective effect to the corneal surface from the direct impact of a high-speed object. Mechanical material properties, wide supporting area and post-lens tear volume acted as protective factors helping to absorb and distribute the kinetic energy of the impacting object. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Fitting Tips and Visual Rehabilitation of Irregular Cornea with a New Design of Corneoscleral Contact Lens: Objective and Subjective Evaluation

PubMed Central

Kishk, Hanem; Elwan, Mohamed M.; Abouelkheir, Hossam Youssef

2018-01-01

Objectives To study the fitting and the visual rehabilitation obtained with a corneoscleral contact lens, namely, Rose K2 XL in patients with irregular cornea. Methods This prospective study included 36 eyes of 36 patients with irregular cornea fitted with Rose K2 XL. Refractive and visual outcomes and mesopic and aberrometric parameters of fitted eyes were assessed at 2 weeks, 3 months, and 6 months after the initial lens use. Objective and subjective parameters of patient satisfaction and lens comfort were noted. Causes of lens discontinuation and complications were also recorded. Results Average logMAR VA improved significantly from 0.95 ± 0.09 without correction to 0.04 ± 0.05 six months after lens wear. Similarly, mesopic and aberrometric measures were significantly improved. Statistical analysis of the subjective patients' responses showed a significant acceptance of the lens by most of them. At the end of follow-up, the mean wearing time was 9.9 ± 2.9 hours per day. The most common cause of wearing discontinuation was persistent discomfort (16.7%) and high lens expenses(16.7%). Self-assessed questionnaire showed statistically significant improvement in nearly all measured subjective parameters. Conclusion Rose K2 XL lenses provide patients with irregular cornea with both quantitative and qualitative optimal visual function with high degree of patient comfort and satisfaction. PMID:29484205

Chapter 03: Correct use of a hand lens

Treesearch

Alex Wiedenhoeft

2011-01-01

A hand lens is a powerful tool for the identification of wood, but like all tools it must be used correctly to take full advantage of its powers. The hand lens has two main parts, a lens that magnifies the object of interest (generally we use 10X or 14X lenses in wood identification; a 14X lens is recommended for use with this manual) and a housing to hold and protect...

Ion photon emission microscope

DOEpatents

Doyle, Barney L.

2003-04-22

An ion beam analysis system that creates microscopic multidimensional image maps of the effects of high energy ions from an unfocussed source upon a sample by correlating the exact entry point of an ion into a sample by projection imaging of the ion-induced photons emitted at that point with a signal from a detector that measures the interaction of that ion within the sample. The emitted photons are collected in the lens system of a conventional optical microscope, and projected on the image plane of a high resolution single photon position sensitive detector. Position signals from this photon detector are then correlated in time with electrical effects, including the malfunction of digital circuits, detected within the sample that were caused by the individual ion that created these photons initially.

Analytical model of the optical vortex microscope.

PubMed

Płocinniczak, Łukasz; Popiołek-Masajada, Agnieszka; Masajada, Jan; Szatkowski, Mateusz

2016-04-20

This paper presents an analytical model of the optical vortex scanning microscope. In this microscope the Gaussian beam with an embedded optical vortex is focused into the sample plane. Additionally, the optical vortex can be moved inside the beam, which allows fine scanning of the sample. We provide an analytical solution of the whole path of the beam in the system (within paraxial approximation)-from the vortex lens to the observation plane situated on the CCD camera. The calculations are performed step by step from one optical element to the next. We show that at each step, the expression for light complex amplitude has the same form with only four coefficients modified. We also derive a simple expression for the vortex trajectory of small vortex displacements.

Multimodality hard-x-ray imaging of a chromosome with nanoscale spatial resolution

DOE PAGES

Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth R.; ...

2016-02-05

Here, we developed a scanning hard x-ray microscope using a new class of x-ray nano-focusing optic called a multilayer Laue lens and imaged a chromosome with nanoscale spatial resolution. The combination of the hard x-ray's superior penetration power, high sensitivity to elemental composition, high spatial-resolution and quantitative analysis creates a unique tool with capabilities that other microscopy techniques cannot provide. Using this microscope, we simultaneously obtained absorption-, phase-, and fluorescence-contrast images of Pt-stained human chromosome samples. The high spatial-resolution of the microscope and its multi-modality imaging capabilities enabled us to observe the internal ultra-structures of a thick chromosome without sectioningmore » it.« less

Multimodality hard-x-ray imaging of a chromosome with nanoscale spatial resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth R.

Here, we developed a scanning hard x-ray microscope using a new class of x-ray nano-focusing optic called a multilayer Laue lens and imaged a chromosome with nanoscale spatial resolution. The combination of the hard x-ray's superior penetration power, high sensitivity to elemental composition, high spatial-resolution and quantitative analysis creates a unique tool with capabilities that other microscopy techniques cannot provide. Using this microscope, we simultaneously obtained absorption-, phase-, and fluorescence-contrast images of Pt-stained human chromosome samples. The high spatial-resolution of the microscope and its multi-modality imaging capabilities enabled us to observe the internal ultra-structures of a thick chromosome without sectioningmore » it.« less

A general purpose wideband optical spatial frequency spectrum analyzer

NASA Technical Reports Server (NTRS)

Ballard, G. S.; Mellor, F. A.

1972-01-01

The light scattered at various angles by a transparent media is studied. An example of these applications is the optical Fourier spectrum measurement resulting from various spatial frequencies which were recorded on a photographic emulsion. A method for obtaining these measurements consists of illuminating the test object with parallel monochromatic light. A stationary lens, placed in the resulting wavefield at a distance of one focal length from the object, will focus parallel waves emanating from the test object at a point lying in the focal plane of the lens. A light detector with a small filtering aperture is then used to measure the intensity variation of the light in the focal or transform plane of the lens. Such measurements require the use of a lens which is highly corrected for all of the common aberrations except chromatic aberration.

Mechanical characterization at material interfaces through dark field Brillouin microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Fiore, Antonio; Scarcelli, Giuliano

2017-02-01

Brillouin microscopy allows high-resolution mapping of the mechanical properties of a sample by measuring the spectra of acoustically induced light scattering therein, and thus has been widely investigated for biomedical application. Measuring the Brillouin spectral shift is challenging when the light is focused onto the interfaces between two materials of different refractive index, because a sizeable portion of the incident light is Fresnel-reflected into the Brillouin spectrometer. To address this need, here, we designed a Brillouin confocal microscope in which the specular reflection at the interface between two materials is physically rejected without significant loss to the Brillouin signal. To achieve this goal, we illuminate the sample with a small-diameter Gaussian beam focused by a high numerical aperture objective lens. In the collection path, the beam reflected from the sample has the same diameter as the incident beam, while the scattered light beam is as large as the clear aperture of the microscope objective. Therefore, using a small blocking filter allows to efficiently reject the reflected light. We calculated the tradeoff between extinction improvement and signal loss when the diameter of the blocking filter is changed. Experimentally, we demonstrated extinction improvement of over 60dB with only 30% signal loss while achieving submicron resolutions. This innovation can be useful for in vivo measurements of the cornea to avoid artifacts in the epithelium and anterior portions of the stroma, as well as to investigate cells cultured on glass coverslips without necessity of index-matching materials.

Multidepth imaging by chromatic dispersion confocal microscopy

NASA Astrophysics Data System (ADS)

Olsovsky, Cory A.; Shelton, Ryan L.; Saldua, Meagan A.; Carrasco-Zevallos, Oscar; Applegate, Brian E.; Maitland, Kristen C.

2012-03-01

Confocal microscopy has shown potential as an imaging technique to detect precancer. Imaging cellular features throughout the depth of epithelial tissue may provide useful information for diagnosis. However, the current in vivo axial scanning techniques for confocal microscopy are cumbersome, time-consuming, and restrictive when attempting to reconstruct volumetric images acquired in breathing patients. Chromatic dispersion confocal microscopy (CDCM) exploits severe longitudinal chromatic aberration in the system to axially disperse light from a broadband source and, ultimately, spectrally encode high resolution images along the depth of the object. Hyperchromat lenses are designed to have severe and linear longitudinal chromatic aberration, but have not yet been used in confocal microscopy. We use a hyperchromat lens in a stage scanning confocal microscope to demonstrate the capability to simultaneously capture information at multiple depths without mechanical scanning. A photonic crystal fiber pumped with a 830nm wavelength Ti:Sapphire laser was used as a supercontinuum source, and a spectrometer was used as the detector. The chromatic aberration and magnification in the system give a focal shift of 140μm after the objective lens and an axial resolution of 5.2-7.6μm over the wavelength range from 585nm to 830nm. A 400x400x140μm3 volume of pig cheek epithelium was imaged in a single X-Y scan. Nuclei can be seen at several depths within the epithelium. The capability of this technique to achieve simultaneous high resolution confocal imaging at multiple depths may reduce imaging time and motion artifacts and enable volumetric reconstruction of in vivo confocal images of the epithelium.

Primate lens capsule elasticity assessed using Atomic Force Microscopy

PubMed Central

Ziebarth, Noël M.; Arrieta, Esdras; Feuer, William J.; Moy, Vincent T.; Manns, Fabrice; Parel, Jean-Marie

2011-01-01

The purpose of this project is to measure the elasticity of the human and non-human primate lens capsule at the microscopic scale using Atomic Force Microscopy (AFM). Elasticity measurements were performed using AFM on the excised anterior lens capsule from 9 cynomolgus monkey (5.9–8.0 years), 8 hamadryas baboon (2.8–10.1 years), and 18 human lenses (33–79 years). Anterior capsule specimens were obtained by performing a 5mm continuous curvilinear capsulorhexis and collecting the resulting disk of capsular tissue. To remove the lens epithelial cells the specimen was soaked in 0.1% trypsin and 0.02% EDTA for five minutes, washed, and placed on a Petri dish and immersed in DMEM. Elasticity measurements of the capsule were performed with a laboratory-built AFM system custom designed for force measurements of ophthalmic tissues. The capsular specimens were probed with an AFM cantilever tip to produce force-indentation curves for each specimen. Young’s modulus was calculated from the force-indentation curves using the model of Sneddon for a conical indenter. Young’s modulus of elasticity was 20.1–131kPa for the human lens capsule, 9.19–117kPa for the cynomolgus lens capsule, and 13.1–62.4kPa for the baboon lens capsule. Young’s modulus increased significantly with age in humans (p=0.03). The age range of the monkey and baboon samples was not sufficient to justify an analysis of age dependence. The capsule elasticity of young humans (<45 years) was not statistically different from that of the monkey and baboon. In humans, there is an increase in lens capsule stiffness at the microscale that could be responsible for an increase in lens capsule bulk stiffness. PMID:21420953

Generation of Functional Lentoid Bodies From Human Induced Pluripotent Stem Cells Derived From Urinary Cells.

PubMed

Fu, Qiuli; Qin, Zhenwei; Jin, Xiuming; Zhang, Lifang; Chen, Zhijian; He, Jiliang; Ji, Junfeng; Yao, Ke

2017-01-01

The pathological mechanisms underlying cataract formation remain largely unknown on account of the lack of appropriate in vitro cellular models. The aim of this study is to develop a stable in vitro system for human lens regeneration using pluripotent stem cells. Isolated human urinary cells were infected with four Yamanaka factors to generate urinary human induced pluripotent stem cells (UiPSCs), which were induced to differentiate into lens progenitor cells and lentoid bodies (LBs). The expression of lens-specific markers was examined by real-time PCR, immunostaining, and Western blotting. The structure and magnifying ability of LBs were investigated using transmission electron microscopy and observing the magnification of the letter "X," respectively. We developed a "fried egg" differentiation method to generate functional LBs from UiPSCs. The UiPSC-derived LBs exhibited crystalline lens-like morphology and a transparent structure and expressed lens-specific markers αA-, αB-, β-, and γ-crystallin and MIP. During LB differentiation, the placodal markers SIX1, EYA1, DLX3, PAX6, and the specific early lens markers SOX1, PROX1, FOXE3, αA-, and αB-crystallin were observed at certain time points. Microscopic examination revealed the presence of lens epithelial cells adjacent to the lens capsule as well as both immature and mature fiber-like cells. Optical analysis further demonstrated the magnifying ability (1.7×) of the LBs generated from UiPSCs. Our study provides the first evidence toward generating functional LBs from UiPSCs, thereby establishing an in vitro system that can be used to study human lens development and cataractogenesis and perhaps even be useful for drug screening.

Visualization of femtosecond laser pulse-induced microincisions inside crystalline lens tissue.

PubMed

Stachs, Oliver; Schumacher, Silvia; Hovakimyan, Marine; Fromm, Michael; Heisterkamp, Alexander; Lubatschowski, Holger; Guthoff, Rudolf

2009-11-01

To evaluate a new method for visualizing femtosecond laser pulse-induced microincisions inside crystalline lens tissue. Laser Zentrum Hannover e.V., Hannover, Germany. Lenses removed from porcine eyes were modified ex vivo by femtosecond laser pulses (wavelength 1040 nm, pulse duration 306 femtoseconds, pulse energy 1.0 to 2.5 microJ, repetition rate 100 kHz) to create defined planes at which lens fibers separate. The femtosecond laser pulses were delivered by a 3-dimension (3-D) scanning unit and transmitted by focusing optics (numerical aperture 0.18) into the lens tissue. Lens fiber orientation and femtosecond laser-induced microincisions were examined using a confocal laser scanning microscope (CLSM) based on a Rostock Cornea Module attached to a Heidelberg Retina Tomograph II. Optical sections were analyzed in 3-D using Amira software (version 4.1.1). Normal lens fibers showed a parallel pattern with diameters between 3 microm and 9 microm, depending on scanning location. Microincision visualization showed different cutting effects depending on pulse energy of the femtosecond laser. The effects ranged from altered tissue-scattering properties with all fibers intact to definite fiber separation by a wide gap. Pulse energies that were too high or overlapped too tightly produced an incomplete cutting plane due to extensive microbubble generation. The 3-D CLSM method permitted visualization and analysis of femtosecond laser pulse-induced microincisions inside crystalline lens tissue. Thus, 3-D CLSM may help optimize femtosecond laser-based procedures in the treatment of presbyopia.

Wavefront correction in two-photon microscopy with a multi-actuator adaptive lens.

PubMed

Bueno, Juan M; Skorsetz, Martin; Bonora, Stefano; Artal, Pablo

2018-05-28

A multi-actuator adaptive lens (AL) was incorporated into a multi-photon (MP) microscope to improve the quality of images of thick samples. Through a hill-climbing procedure the AL corrected for the specimen-induced aberrations enhancing MP images. The final images hardly differed when two different metrics were used, although the sets of Zernike coefficients were not identical. The optimized MP images acquired with the AL were also compared with those obtained with a liquid-crystal-on-silicon spatial light modulator. Results have shown that both devices lead to similar images, which corroborates the usefulness of this AL for MP imaging.

Densely packed beta-structure at the protein-lipid interface of porin is revealed by high-resolution cryo-electron microscopy.

PubMed

Sass, H J; Büldt, G; Beckmann, E; Zemlin, F; van Heel, M; Zeitler, E; Rosenbusch, J P; Dorset, D L; Massalski, A

1989-09-05

Porin is an integral membrane protein that forms channels across the outer membrane of Escherichia coli. Electron microscopic studies of negatively stained two-dimensional porin crystals have shown three stain accumulations per porin trimer, revealing the locations of pores spanning the membrane. In this study, reconstituted porin lattices embedded in glucose were investigated using the low-dose technique on a cryo-electron microscope equipped with a helium-cooled superconducting objective lens. The specimen temperature was maintained at 5 K to yield an improved microscopic and specimen stability. Under these conditions, we obtained for the first time electron diffraction patterns from porin lattices to a resolution of 3.2 A and images showing optical diffraction up to a resolution of 4.9 A. Applying correlation averaging techniques to the digitized micrographs, we were able to reconstruct projected images of the porin trimer to a resolution of up to 3.5 A. In the final projection maps, amplitudes from electron diffraction and phases from these images were combined. The predominant feature is a high-density narrow band (about 6 A in thickness) that delineates the outer perimeter of the trimer. Since the molecule consists of almost exclusively beta-sheet structure, as revealed by spectroscopic data, we conclude that this band is a cylindrical beta-pleated sheet crossing the membrane nearly perpendicularly to its plane. Another intriguing finding is a low-density area (about 70 A2) situated in the centre of the trimer.

Video-mosaicking of in vivo reflectance confocal microscopy images for noninvasive examination of skin lesion (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kose, Kivanc; Gou, Mengran; Yelamos, Oriol; Cordova, Miguel A.; Rossi, Anthony; Nehal, Kishwer S.; Camps, Octavia I.; Dy, Jennifer G.; Brooks, Dana H.; Rajadhyaksha, Milind

2017-02-01

In this report we describe a computer vision based pipeline to convert in-vivo reflectance confocal microscopy (RCM) videos collected with a handheld system into large field of view (FOV) mosaics. For many applications such as imaging of hard to access lesions, intraoperative assessment of MOHS margins, or delineation of lesion margins beyond clinical borders, raster scan based mosaicing techniques have clinically significant limitations. In such cases, clinicians often capture RCM videos by freely moving a handheld microscope over the area of interest, but the resulting videos lose large-scale spatial relationships. Videomosaicking is a standard computational imaging technique to register, and stitch together consecutive frames of videos into large FOV high resolution mosaics. However, mosaicing RCM videos collected in-vivo has unique challenges: (i) tissue may deform or warp due to physical contact with the microscope objective lens, (ii) discontinuities or "jumps" between consecutive images and motion blur artifacts may occur, due to manual operation of the microscope, and (iii) optical sectioning and resolution may vary between consecutive images due to scattering and aberrations induced by changes in imaging depth and tissue morphology. We addressed these challenges by adapting or developing new algorithmic methods for videomosaicking, specifically by modeling non-rigid deformations, followed by automatically detecting discontinuities (cut locations) and, finally, applying a data-driven image stitching approach that fully preserves resolution and tissue morphologic detail without imposing arbitrary pre-defined boundaries. We will present example mosaics obtained by clinical imaging of both melanoma and non-melanoma skin cancers. The ability to combine freehand mosaicing for handheld microscopes with preserved cellular resolution will have high impact application in diverse clinical settings, including low-resource healthcare systems.

Using machine-learning to optimize phase contrast in a low-cost cellphone microscope

PubMed Central

Wartmann, Rolf; Schadwinkel, Harald; Heintzmann, Rainer

2018-01-01

Cellphones equipped with high-quality cameras and powerful CPUs as well as GPUs are widespread. This opens new prospects to use such existing computational and imaging resources to perform medical diagnosis in developing countries at a very low cost. Many relevant samples, like biological cells or waterborn parasites, are almost fully transparent. As they do not exhibit absorption, but alter the light’s phase only, they are almost invisible in brightfield microscopy. Expensive equipment and procedures for microscopic contrasting or sample staining often are not available. Dedicated illumination approaches, tailored to the sample under investigation help to boost the contrast. This is achieved by a programmable illumination source, which also allows to measure the phase gradient using the differential phase contrast (DPC) [1, 2] or even the quantitative phase using the derived qDPC approach [3]. By applying machine-learning techniques, such as a convolutional neural network (CNN), it is possible to learn a relationship between samples to be examined and its optimal light source shapes, in order to increase e.g. phase contrast, from a given dataset to enable real-time applications. For the experimental setup, we developed a 3D-printed smartphone microscope for less than 100 $ using off-the-shelf components only such as a low-cost video projector. The fully automated system assures true Koehler illumination with an LCD as the condenser aperture and a reversed smartphone lens as the microscope objective. We show that the effect of a varied light source shape, using the pre-trained CNN, does not only improve the phase contrast, but also the impression of an improvement in optical resolution without adding any special optics, as demonstrated by measurements. PMID:29494620

A fiber-optic fluorescence microscope using a consumer-grade digital camera for in vivo cellular imaging.

PubMed

Shin, Dongsuk; Pierce, Mark C; Gillenwater, Ann M; Williams, Michelle D; Richards-Kortum, Rebecca R

2010-06-23

Early detection is an essential component of cancer management. Unfortunately, visual examination can often be unreliable, and many settings lack the financial capital and infrastructure to operate PET, CT, and MRI systems. Moreover, the infrastructure and expense associated with surgical biopsy and microscopy are a challenge to establishing cancer screening/early detection programs in low-resource settings. Improvements in performance and declining costs have led to the availability of optoelectronic components, which can be used to develop low-cost diagnostic imaging devices for use at the point-of-care. Here, we demonstrate a fiber-optic fluorescence microscope using a consumer-grade camera for in vivo cellular imaging. The fiber-optic fluorescence microscope includes an LED light, an objective lens, a fiber-optic bundle, and a consumer-grade digital camera. The system was used to image an oral cancer cell line labeled with 0.01% proflavine. A human tissue specimen was imaged following surgical resection, enabling dysplastic and cancerous regions to be evaluated. The oral mucosa of a healthy human subject was imaged in vivo, following topical application of 0.01% proflavine. The fiber-optic microscope resolved individual nuclei in all specimens and tissues imaged. This capability allowed qualitative and quantitative differences between normal and precancerous or cancerous tissues to be identified. The optical efficiency of the system permitted imaging of the human oral mucosa in real time. Our results indicate this device as a useful tool to assist in the identification of early neoplastic changes in epithelial tissues. This portable, inexpensive unit may be particularly appropriate for use at the point-of-care in low-resource settings.

Subjective vs Objective Accommodative Amplitude: Preschool to Presbyopia

PubMed Central

Anderson, Heather A.; Stuebing, Karla K.

2014-01-01

Purpose This study compared subjective and objective accommodative amplitudes to characterize changes from preschool to presbyopia. Methods Monocular accommodative amplitude was measured with three techniques in random order (subjective push-up, objective minus lens stimulated, and objective proximal stimulated) on 236 subjects 3–64 years using a 1.5mm letter. Subjective push-up amplitudes were the dioptric distance at which the target first blurred along a near-point rod. Objective minus lens stimulated amplitudes were the greatest accommodative response obtained by Grand Seiko autorefraction as subjects viewed the stimulus at 33cm through increasing minus lens powers. Objective proximal stimulated amplitudes were the greatest accommodative response obtained by Grand Seiko autorefraction as subjects viewed the stimulus at increasing proximity from 40cm up to 3.33cm. Results In comparison with subjective push-up amplitudes, objective amplitudes were lower at all ages, with the most dramatic difference occurring in the 3–5 year group (subjective push-up = 16.00 ± 4.98D versus objective proximal stimulated = 7.94 ± 2.37D and objective lens stimulated = 6.20 ± 1.99D). Objective proximal and lens stimulated amplitudes were largest in the 6–10 year group (8.81 ± 1.24D and 8.05 ± 1.82D, respectively) and gradually decreased until the fourth decade of life when a rapid decline to presbyopia occurred. There was a significant linear relationship between objective techniques (y = 0.74 + 0.96x, R2 = 0.85, p<0.001) with greater amplitudes measured for the proximal stimulated technique (mean difference = 0.55D). Conclusions Objective measurements of accommodation demonstrate that accommodative amplitude is substantially less than that measured by the subjective push-up technique, particularly in young children. These findings have important clinical implications for the management of uncorrected hyperopia. PMID:25602235

Gamma-Ray Telescope and Uncertainty Principle

ERIC Educational Resources Information Center

Shivalingaswamy, T.; Kagali, B. A.

2012-01-01

Heisenberg's Uncertainty Principle is one of the important basic principles of quantum mechanics. In most of the books on quantum mechanics, this uncertainty principle is generally illustrated with the help of a gamma ray microscope, wherein neither the image formation criterion nor the lens properties are taken into account. Thus a better…

Early Childhood Socialization: Societal Context and Childrearing Values in Hungary

ERIC Educational Resources Information Center

Brayfield, April; Korintus, Marta

2011-01-01

This article examines the socio-cultural context of early childhood socialization in Hungary. Using a macroscopic lens, we describe the national demographic situation and the social organization of early childhood education and care. Our analysis then shifts to a microscopic focus on parental values and beliefs about the substance of what young…

A Volumetric Flask as a Projector

ERIC Educational Resources Information Center

Limsuwan, P.; Asanithi, P.; Thongpool, V.; Piriyawong, V.; Limsuwan, S.

2012-01-01

A lens based on liquid in the confined volume of a volumetric flask was presented as a potential projector to observe microscopic floating organisms or materials. In this experiment, a mosquito larva from a natural pond was selected as a demonstration sample. By shining a light beam from a laser pointer of any visible wavelength through the…

In vivo laser confocal microscopic analysis of murine cornea and lens microstructures.

PubMed

Yuasa, Masashi; Kobayashi, Akira; Yokogawa, Hideaki; Sugiyama, Kazuhisa

2008-01-01

The purpose of the current study is to investigate in vivo microstructures of anterior segments of normal murine eyes by new-generation in vivo laser confocal microscopy. Twenty-six corneas and lenses from 13 mice were analyzed by in vivo laser confocal microscopy. Murine corneal superficial cells formed a polygonal cell pattern, with a mean cell density of 577 +/- 115 cells/mm2 (mean +/- standard deviation). Corneal basal epithelial cells had dark cytoplasm and were closely organized (9,312 +/- 1,777 cells/mm2). Sub-basal nerve fiber bundles were arranged in a whorl pattern, with both clockwise and counter-clockwise patterns. In the stroma, keratocytes were observed as numerous reflective stellate structures. The endothelial cells were organized in a honeycomb pattern (2,463 +/- 292 cells/mm2). Deeper inside the eye, murine lens epithelial cells were organized in a regular pattern (4,168 +/- 636 cells/mm2) and numerous lens fibers were observed. In vivo laser confocal microscopy can provide high-resolution images of all corneal layers and lens structures of mice without sacrificing animals or tissue preparation.

Ultrasound biomicroscopy. High-frequency ultrasound imaging of the eye at microscopic resolution.

PubMed

Pavlin, C J; Foster, F S

1998-11-01

UBM presents us with a new method of imaging the anterior segment of the eye at high resolution. Its strengths lie in its ability to produce cross-sections of the living eye at microscopic resolution without violating the integrity of the globe. UBM, although lacking the resolution of optical microscopy, gives us images in living eyes without affecting the internal relationships of the structures imaged. There are many other applications of this new imaging method. Examples of other uses include imaging adnexal pathology, assessing corneal changes with refractive surgery, the assessment of trauma, and determination of intraocular lens position.

SIL-STED microscopy technique enhancing super-resolution of fluorescence microscopy

NASA Astrophysics Data System (ADS)

Park, No-Cheol; Lim, Geon; Lee, Won-sup; Moon, Hyungbae; Choi, Guk-Jong; Park, Young-Pil

2017-08-01

We have characterized a new type STED microscope which combines a high numerical aperture (NA) optical head with a solid immersion lens (SIL), and we call it as SIL-STED microscope. The advantage of a SIL-STED microscope is that its high NA of the SIL makes it superior to a general STED microscope in lateral resolution, thus overcoming the optical diffraction limit at the macromolecular level and enabling advanced super-resolution imaging of cell surface or cell membrane structure and function Do. This study presents the first implementation of higher NA illumination in a STED microscope limiting the fluorescence lateral resolution to about 40 nm. The refractive index of the SIL which is made of material KTaO3 is about 2.23 and 2.20 at a wavelength of 633 nm and 780 nm which are used for excitation and depletion in STED imaging, respectively. Based on the vector diffraction theory, the electric field focused by the SILSTED microscope is numerically calculated so that the numerical results of the point dispersion function of the microscope and the expected resolution could be analyzed. For further investigation, fluorescence imaging of nano size fluorescent beads is fulfilled to show improved performance of the technique.

TRIO Platform: A Novel Low Profile In vivo Imaging Support and Restraint System for Mice.

PubMed

Voziyanov, Vladislav; Kemp, Benjamin S; Dressel, Chelsea A; Ponder, Kayla; Murray, Teresa A

2016-01-01

High resolution, in vivo optical imaging of the mouse brain over time often requires anesthesia, which necessitates maintaining the animal's body temperature and level of anesthesia, as well as securing the head in an optimal, stable position. Controlling each parameter usually requires using multiple systems. Assembling multiple components into the small space on a standard microscope stage can be difficult and some commercially available parts simply do not fit. Furthermore, it is time-consuming to position an animal in the identical position over multiple imaging sessions for longitudinal studies. This is especially true when using an implanted gradient index (GRIN) lens for deep brain imaging. The multiphoton laser beam must be parallel with the shaft of the lens because even a slight tilt of the lens can degrade image quality. In response to these challenges, we have designed a compact, integrated in vivo imaging support system to overcome the problems created by using separate systems during optical imaging in mice. It is a single platform that provides (1) sturdy head fixation, (2) an integrated gas anesthesia mask, and (3) safe warm water heating. This THREE-IN-ONE (TRIO) Platform has a small footprint and a low profile that positions a mouse's head only 20 mm above the microscope stage. This height is about one half to one third the height of most commercially available immobilization devices. We have successfully employed this system, using isoflurane in over 40 imaging sessions with an average of 2 h per session with no leaks or other malfunctions. Due to its smaller size, the TRIO Platform can be used with a wider range of upright microscopes and stages. Most of the components were designed in SOLIDWORKS® and fabricated using a 3D printer. This additive manufacturing approach also readily permits size modifications for creating systems for other small animals.

TRIO Platform: A Novel Low Profile In vivo Imaging Support and Restraint System for Mice

PubMed Central

Voziyanov, Vladislav; Kemp, Benjamin S.; Dressel, Chelsea A.; Ponder, Kayla; Murray, Teresa A.

2016-01-01

High resolution, in vivo optical imaging of the mouse brain over time often requires anesthesia, which necessitates maintaining the animal's body temperature and level of anesthesia, as well as securing the head in an optimal, stable position. Controlling each parameter usually requires using multiple systems. Assembling multiple components into the small space on a standard microscope stage can be difficult and some commercially available parts simply do not fit. Furthermore, it is time-consuming to position an animal in the identical position over multiple imaging sessions for longitudinal studies. This is especially true when using an implanted gradient index (GRIN) lens for deep brain imaging. The multiphoton laser beam must be parallel with the shaft of the lens because even a slight tilt of the lens can degrade image quality. In response to these challenges, we have designed a compact, integrated in vivo imaging support system to overcome the problems created by using separate systems during optical imaging in mice. It is a single platform that provides (1) sturdy head fixation, (2) an integrated gas anesthesia mask, and (3) safe warm water heating. This THREE-IN-ONE (TRIO) Platform has a small footprint and a low profile that positions a mouse's head only 20 mm above the microscope stage. This height is about one half to one third the height of most commercially available immobilization devices. We have successfully employed this system, using isoflurane in over 40 imaging sessions with an average of 2 h per session with no leaks or other malfunctions. Due to its smaller size, the TRIO Platform can be used with a wider range of upright microscopes and stages. Most of the components were designed in SOLIDWORKS® and fabricated using a 3D printer. This additive manufacturing approach also readily permits size modifications for creating systems for other small animals. PMID:27199633

Extending Whole Slide Imaging: Color Darkfield Internal Reflection Illumination (DIRI) for Biological Applications

PubMed Central

Namiki, Kana; Miyawaki, Atsushi; Ishikawa, Takuji

2017-01-01

Whole slide imaging (WSI) is a useful tool for multi-modal imaging, and in our work, we have often combined WSI with darkfield microscopy. However, traditional darkfield microscopy cannot use a single condenser to support high- and low-numerical-aperture objectives, which limits the modality of WSI. To overcome this limitation, we previously developed a darkfield internal reflection illumination (DIRI) microscope using white light-emitting diodes (LEDs). Although the developed DIRI is useful for biological applications, substantial problems remain to be resolved. In this study, we propose a novel illumination technique called color DIRI. The use of three-color LEDs dramatically improves the capability of the system, such that color DIRI (1) enables optimization of the illumination color; (2) can be combined with an oil objective lens; (3) can produce fluorescence excitation illumination; (4) can adjust the wavelength of light to avoid cell damage or reactions; and (5) can be used as a photostimulator. These results clearly illustrate that the proposed color DIRI can significantly extend WSI modalities for biological applications. PMID:28085892

Spectral analysis and comparison of mineral deposits forming in opacified intraocular lens and senile cataractous lens

NASA Astrophysics Data System (ADS)

Lin, Shan-Yang; Chen, Ko-Hwa; Lin, Chih-Cheng; Cheng, Wen-Ting; Li, Mei-Jane

2010-10-01

This preliminary report was attempted to compare the chemical components of mineral deposits on the surfaces of an opacified intraocular lens (IOL) and a calcified senile cataractous lens (SCL) by vibrational spectral diagnosis. An opacified intraocular lens (IOL) was obtained from a 65-year-old male patient who had a significant decrease in visual acuity 2-years after an ocular IOL implantation. Another SCL with grayish white calcified plaque on the subcapsular cortex was isolated from a 79-year-old male patient with complicated cataract after cataract surgery. Optical light microscope was used to observe both samples and gross pictures were taken. Fourier transform infrared (FT-IR) and Raman microspectroscopic techniques were employed to analyze the calcified deposits. The curve-fitting algorithm using the Gaussian function was also used to quantitatively estimate the chemical components in each deposit. The preliminary results of spectral diagnosis indicate that the opacified IOL mainly consisted of the poorly crystalline, immature non-stoichiometric hydroxyapatite (HA) with higher content of type B carbonated apatites. However, the calcified plaque deposited on the SCL was comprised of a mature crystalline stoichiometric HA having higher contents of type A and type B carbonate apatites. More case studies should be examined in future.

PtyNAMi: ptychographic nano-analytical microscope at PETRA III: interferometrically tracking positions for 3D x-ray scanning microscopy using a ball-lens retroreflector

NASA Astrophysics Data System (ADS)

Schroer, Christian G.; Seyrich, Martin; Kahnt, Maik; Botta, Stephan; Döhrmann, Ralph; Falkenberg, Gerald; Garrevoet, Jan; Lyubomirskiy, Mikhail; Scholz, Maria; Schropp, Andreas; Wittwer, Felix

2017-09-01

In recent years, ptychography has revolutionized x-ray microscopy in that it is able to overcome the diffraction limit of x-ray optics, pushing the spatial resolution limit down to a few nanometers. However, due to the weak interaction of x rays with matter, the detection of small features inside a sample requires a high coherent fluence on the sample, a high degree of mechanical stability, and a low background signal from the x-ray microscope. The x-ray scanning microscope PtyNAMi at PETRA III is designed for high-spatial-resolution 3D imaging with high sensitivity. The design concept is presented with a special focus on real-time metrology of the sample position during tomographic scanning microscopy.

Single cell manipulation utilizing femtosecond laser-induced shock and stress waves

NASA Astrophysics Data System (ADS)

Hosokawa, Yoichiroh

2017-02-01

When an intense femtosecond laser pulse is focused into a culture medium through an objective lens, an impulsive force is loaded on the cells with generations of the shock and stress waves at the laser focal point. The shock and stress waves were acted to single cells in the vicinity of the laser focal point as an impulsive force. We have applied the impulsive force to manipulate single cells. As the transient intensity of the impulsive force is over 1000 times stronger than the force due to optical tweezers, drastic single manipulation which is difficult by the optical tweezers can be realized. The generation process of the impulsive force and behavior of animal cell after loading the impulsive force were reviewed, and then our original quantification method of the impulsive force utilizing atomic force microscope (AFM) was introduced with its applications for evaluating adhesions between animal cells and between sub-organelles in plant cell.

Direct-to-digital holography and holovision

DOEpatents

Thomas, Clarence E.; Baylor, Larry R.; Hanson, Gregory R.; Rasmussen, David A.; Voelkl, Edgar; Castracane, James; Simkulet, Michelle; Clow, Lawrence

2000-01-01

Systems and methods for direct-to-digital holography are described. An apparatus includes a laser; a beamsplitter optically coupled to the laser; a reference beam mirror optically coupled to the beamsplitter; an object optically coupled to the beamsplitter, a focusing lens optically coupled to both the reference beam mirror and the object; and a digital recorder optically coupled to the focusing lens. A reference beam is incident upon the reference beam mirror at a non-normal angle, and the reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form an image. The systems and methods provide advantages in that computer assisted holographic measurements can be made.

Virtual mask digital electron beam lithography

DOEpatents

Baylor, L.R.; Thomas, C.E.; Voelkl, E.; Moore, J.A.; Simpson, M.L.; Paulus, M.J.

1999-04-06

Systems and methods for direct-to-digital holography are described. An apparatus includes a laser; a beamsplitter optically coupled to the laser; a reference beam mirror optically coupled to the beamsplitter; an object optically coupled to the beamsplitter, a focusing lens optically coupled to both the reference beam mirror and the object; and a digital recorder optically coupled to the focusing lens. A reference beam is incident upon the reference beam mirror at a non-normal angle, and the reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form an image. The systems and methods provide advantages in that computer assisted holographic measurements can be made. 5 figs.

Virtual mask digital electron beam lithography

DOEpatents

Baylor, Larry R.; Thomas, Clarence E.; Voelkl, Edgar; Moore, James A.; Simpson, Michael L.; Paulus, Michael J.

1999-01-01

Systems and methods for direct-to-digital holography are described. An apparatus includes a laser; a beamsplitter optically coupled to the laser; a reference beam mirror optically coupled to the beamsplitter; an object optically coupled to the beamsplitter, a focusing lens optically coupled to both the reference beam mirror and the object; and a digital recorder optically coupled to the focusing lens. A reference beam is incident upon the reference beam mirror at a non-normal angle, and the reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form an image. The systems and methods provide advantages in that computer assisted holographic measurements can be made.

Microoptical compound lens

DOEpatents

Sweatt, William C.; Gill, David D.

2007-10-23

An apposition microoptical compound lens comprises a plurality of lenslets arrayed around a segment of a hollow, three-dimensional optical shell. The lenslets collect light from an object and focus the light rays onto the concentric, curved front surface of a coherent fiber bundle. The fiber bundle transports the light rays to a planar detector, forming a plurality of sub-images that can be reconstructed as a full image. The microoptical compound lens can have a small size (millimeters), wide field of view (up to 180.degree.), and adequate resolution for object recognition and tracking.

Tethered capsule OCT endomicroscopy for upper gastrointestinal tract imaging by using ball lens probe (Conference Presentation)

NASA Astrophysics Data System (ADS)

Dong, Jing; Gora, Michalina J.; Reddy, Rohith; Trasischker, Wolfgang; Poupart, Oriane; Lu, Weina; Carruth, Robert W.; Grant, Catriona N.; Soomro, Amna R.; Tiernan, Aubrey R.; Rosenberg, Mireille; Nishioka, Norman S.; Tearney, Guillermo J.

2016-03-01

While endoscopy is the most commonly used modality for diagnosing upper GI tract disease, this procedure usually requires patient sedation that increases cost and mandates its operation in specialized settings. In addition, endoscopy only visualizes tissue superfically at the macroscopic scale, which is problematic for many diseases that manifest below the surface at a microscopic scale. Our lab has previously developed technology termed tethered capsule OCT endomicroscopy (TCE) to overcome these diagnostic limitations of endoscopy. The TCE device is a swallowable capsule that contains optomechanical components that circumferentially scan the OCT beam inside the body as the pill traverses the organ via peristalsis. While we have successfully imaged ~100 patients with the TCE device, the optics of our current device have many elements and are complex, comprising a glass ferrule, optical fiber, glass spacer, GRIN lens and prism. As we scale up manufacturing of this device for clinical translation, we must decrease the cost and improve the manufacturability of the capsule's optical configuration. In this abstract, we report on the design and development of simplificed TCE optics that replace the GRIN lens-based configuration with an angle-polished ball lens design. The new optics include a single mode optical fiber, a glass spacer and an angle polished ball lens, that are all fusion spliced together. The ball lens capsule has resolutions that are comparable with those of our previous GRIN lens configuration (30µm (lateral) × 7 µm (axial)). Results in human subjects show that OCT-based TCE using the ball lens not only provides rapid, high quality microstructural images of upper GI tract, but also makes it possible to implement this technology inexpensively and on a larger scale.

Heterochromatic Flicker Photometry for Objective Lens Density Quantification.

PubMed

Najjar, Raymond P; Teikari, Petteri; Cornut, Pierre-Loïc; Knoblauch, Kenneth; Cooper, Howard M; Gronfier, Claude

2016-03-01

Although several methods have been proposed to evaluate lens transmittance, to date there is no consensual in vivo approach in clinical practice. The aim of this study was to compare ocular lens density and transmittance measurements obtained by an improved psychophysical scotopic heterochromatic flicker photometry (sHFP) technique to the results obtained by three other measures: a psychophysical threshold technique, a Scheimpflug imaging technique, and a clinical assessment using a validated subjective scale. Forty-three subjects (18 young, 9 middle aged, and 16 older) were included in the study. Individual lens densities were measured and transmittance curves were derived from sHFP indexes. Ocular lens densities were compared across methods by using linear regression analysis. The four approaches showed a quadratic increase in lens opacification with age. The sHFP technique revealed that transmittance decreased with age over the entire visual spectrum. This decrease was particularly pronounced between young and older participants in the short (53.03% decrease in the 400-500 nm range) wavelength regions of the light spectrum. Lens density derived from sHFP highly correlated with the values obtained with the other approaches. Compared to other objective measures, sHFP also showed the lowest variability and the best fit with a quadratic trend (r2 = 0.71) of lens density increase as a function of age. The sHFP technique offers a practical, reliable, and accurate method to measure lens density in vivo and predict lens transmittance over the visible spectrum. An accurate quantification of lens transmittance should be obtained in clinical practice, but also in research in visual and nonvisual photoreception.

Space Optical Communications Using Laser Beams

NASA Technical Reports Server (NTRS)

Goorjian, Peter M. (Inventor)

2017-01-01

A system for communicating between an object in space and a ground station, between objects in space, or between ground stations, includes a telecentric lens. Photodetectors positioned upon a focal plane of the telecentric lens detect an inbound light beam, received from a source, that has passed through the telecentric lens to the focal plane. Lasers positioned upon the focal plane transmit light beams from the focal plane through the telecentric lens to an area that includes the source of the inbound light beam. A processor detect signals from individual photodetectors corresponding to light detected, and selectively signals individual lasers that are close to those photodetectors, resulting in a returning beam that arrives close to the source, and which carries encoded data.

Scanning transmission x-ray microscope for materials science spectromicroscopy at the ALS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warwick, T.; Seal, S.; Shin, H.

1997-04-01

The brightness of the Advanced Light Source will be exploited by several new instruments for materials science spectromicroscopy over the next year or so. The first of these to become operational is a scanning transmission x-ray microscope with which near edge x-ray absorption spectra (NEXAFS) can be measured on spatial features of sub-micron size. Here the authors describe the instrument as it is presently implemented, its capabilities, some studies made to date and the developments to come. The Scanning Transmission X-ray Microscope makes use of a zone plate lens to produce a small x-ray spot with which to perform absorptionmore » spectroscopy through thin samples. The x-ray beam from ALS undulator beamline 7.0 emerges into the microscope vessel through a silicon nitride vacuum window 160nm thick and 300{mu}m square. The vessel is filled with helium at atmospheric pressure. The zone plate lens is illuminated 1mm downstream from the vacuum window and forms an image in first order of a pinhole which is 3m upstream in the beamline. An order sorting aperture passes the first order converging light and blocks the unfocused zero order. The sample is at the focus a few mm downstream of the zone plate and mounted from a scanning piezo stage which rasters in x and y so that an image is formed, pixel by pixel, by an intensity detector behind the sample. Absorption spectra are measured point-by-point as the photon energy is scanned by rotating the diffraction grating in the monochromator and changing the undulator gap.« less

Fast-response variable focusing micromirror array lens

NASA Astrophysics Data System (ADS)

Boyd, James G., IV; Cho, Gyoungil

2003-07-01

A reflective type Fresnel lens using an array of micromirrors is designed and fabricated using the MUMPs® surface micromachining process. The focal length of the lens can be rapidly changed by controlling both the rotation and translation of electrostatically actuated micromirrors. The rotation converges rays and the translation adjusts the optical path length difference of the rays to be integer multiples of the wavelength. The suspension spring, pedestal and electrodes are located under the mirror to maximize the optical efficiency. Relations are provided for the fill-factor and the numerical aperture as functions of the lens diameter, the mirror size, and the tolerances specified by the MUMPs® design rules. The fabricated lens is 1.8mm in diameter, and each micromirror is approximately 100mm x 100mm. The lens fill-factor is 83.7%, the numerical aperture is 0.018 for a wavelength of 632.8nm, and the resolution is approximately 22mm, whereas the resolution of a perfect aberration-free lens is 21.4μm for a NA of 0.018. The focal length ranges from 11.3mm to infinity. The simulated Strehl ratio, which is the ratio of the point spread function maximum intensity to the theoretical diffraction-limited PSF maximum intensity, is 31.2%. A mechanical analysis was performed using the finite element code IDEAS. The combined maximum rotation and translation produces a maximum stress of 301MPa, below the yield strength of polysilicon, 1.21 to 1.65GPa. Potential applications include adaptive microscope lenses for scanning particle imaging velocimetry and a visually aided micro-assembly.

Plane development of lateral surfaces for inspection systems

NASA Astrophysics Data System (ADS)

Francini, F.; Fontani, D.; Jafrancesco, D.; Mercatelli, L.; Sansoni, P.

2006-08-01

The problem of developing the lateral surfaces of a 3D object can arise in item inspection using automated imaging systems. In an industrial environment, these control systems typically work at high rate and they have to assure a reliable inspection of the single item. For compactness requirements it is not convenient to utilise three or four CCD cameras to control all the lateral surfaces of an object. Moreover it is impossible to mount optical components near the object if it is placed on a conveyor belt. The paper presents a system that integrates on a single CCD picture the images of both the frontal surface and the lateral surface of an object. It consists of a freeform lens mounted in front of a CCD camera with a commercial lens. The aim is to have a good magnification of the lateral surface, maintaining a low aberration level for exploiting the pictures in an image processing software. The freeform lens, made in plastics, redirects the light coming from the object to the camera lens. The final result is to obtain on the CCD: - the frontal and lateral surface images, with a selected magnification (even with two different values for the two images); - a gap between these two images, so an automatic method to analyse the images can be easily applied. A simple method to design the freeform lens is illustrated. The procedure also allows to obtain the imaging system modifying a current inspection system reducing the cost.

[Pars plana vitrectomy with the vitreous stripper].

PubMed

Klöti, R

1975-01-01

We report on the construction and the function of a new microsurgical instrument for vitrectomy. The instrument is introduced into the vitreous cavity through a small scleral incision in the pars plana area. Microscope observation with slit-lamp illumination and a specially designed contact lens are used for this surgical procedure. Our clinical experiences and the indications are discussed.

Enhancing micrographs obtained with a scanning acoustic microscope using false-color encoding

NASA Astrophysics Data System (ADS)

Hammer, R.; Hollis, R. L.

1982-04-01

The periodic signal variations observed in reflection acoustic microscopy when lens-to-sample spacing is changed lead to reversals in image contrast. This contrast mechanism can be described by a V(Z) function, where V is the transducer voltage and Z the lens-to-sample spacing. In this work we show how by obtaining V(Z) curves from each plane of a complex sample, judicious choices of focal positions can be made to optimize signals from planes of interest, which allows color encoding of the image from each plane in an overlay image. We present false-color micrographs obtained in this way, along with A scans and V(Z) curves to demonstrate the technique.

Methods and devices for measuring orbital angular momentum states of electrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMorran, Benjamin J.; Harvey, Tyler R.

A device for measuring electron orbital angular momentum states in an electron microscope includes the following components aligned sequentially in the following order along an electron beam axis: a phase unwrapper (U) that is a first electrostatic refractive optical element comprising an electrode and a conductive plate, where the electrode is aligned perpendicular to the conductive plate; a first electron lens system (L1); a phase corrector (C) that is a second electrostatic refractive optical element comprising an array of electrodes with alternating electrostatic bias; and a second electron lens system (L2). The phase unwrapper may be a needle electrode ormore » knife edge electrode.« less

Angular and linear fields of view of Galilean telescopes and telemicroscopes.

PubMed

Katz, Milton

2007-06-01

The calculation of the angular fields of view (FOVs) of Galilean telescopes generally necessitates the calculation of the pupils and ports. This, in turn, requires knowledge of the optical design of the telescope, in particular, the focal lengths or powers of the objective and ocular lenses. Equations for finding the FOV that obviate the need to calculate pupils and ports, or even to know the lens powers of the telescope, are presented in this article. The equations can be used to find the FOVs in image space of real Galilean telescopes of known magnification, merely by measuring the distance between the objective and ocular lenses and the diameter of the objective lens. The equations include the effects of eye pupil diameter and eye relief. Linear FOVs (LFOVs) of Galilean telemicroscopes are similarly determined. Two image space angular FOV equations were derived: (1) an equation to determine the angular FOVs of a telescope with various amounts of vignetting and eye relief; and (2) an equivalent equation for the LFOVs of telescopes fitted with lens caps for near vision. The FOV increases linearly with increasing vignetting. Increasing the eye relief results in a nonlinear decrease in the FOV, shown as a fraction of the normalized value for zero eye relief. Decrements in the FOVs with increasing eye relief as a fraction of the normalized field angle when the eye relief = 0 are shown to be constant regardless of the vignetting level. A transition of the objective lens from field stop to aperture stop occurs when the eye pupil diameter exceeds the diameter of the objective lens divided by the magnification. Equations have been derived for Galilean telescopes and telemicroscopes that make it unnecessary to find pupils and ports, or to know the powers of the lenses. They provide a direct and simple evaluation of angular and LFOVs as functions of magnification, objective lens diameter, eye pupil diameter, eye relief, and vignetting, and enable comparisons of actual telescopes.

Lensless digital holography with diffuse illumination through a pseudo-random phase mask.

PubMed

Bernet, Stefan; Harm, Walter; Jesacher, Alexander; Ritsch-Marte, Monika

2011-12-05

Microscopic imaging with a setup consisting of a pseudo-random phase mask, and an open CMOS camera, without an imaging objective, is demonstrated. The pseudo random phase mask acts as a diffuser for an incoming laser beam, scattering a speckle pattern to a CMOS chip, which is recorded once as a reference. A sample which is afterwards inserted somewhere in the optical beam path changes the speckle pattern. A single (non-iterative) image processing step, comparing the modified speckle pattern with the previously recorded one, generates a sharp image of the sample. After a first calibration the method works in real-time and allows quantitative imaging of complex (amplitude and phase) samples in an extended three-dimensional volume. Since no lenses are used, the method is free from lens abberations. Compared to standard inline holography the diffuse sample illumination improves the axial sectioning capability by increasing the effective numerical aperture in the illumination path, and it suppresses the undesired so-called twin images. For demonstration, a high resolution spatial light modulator (SLM) is programmed to act as the pseudo-random phase mask. We show experimental results, imaging microscopic biological samples, e.g. insects, within an extended volume at a distance of 15 cm with a transverse and longitudinal resolution of about 60 μm and 400 μm, respectively.

Imaging slit-coupled surface plasmon polaritons using conventional optical microscopy.

PubMed

Mehfuz, R; Chowdhury, F A; Chau, K J

2012-05-07

We develop a technique that now enables surface plasmon polaritons (SPPs) coupled by nano-patterned slits in a metal film to be detected using conventional optical microscopy with standard objective lenses. The crux of this method is an ultra-thin polymer layer on the metal surface, whose thickness can be varied over a nanoscale range to enable controllable tuning of the SPP momentum. At an optimal layer thickness for which the SPP momentum matches the momentum of light emerging from the slit, the SPP coupling efficiency is enhanced about six times relative to that without the layer. The enhanced efficiency results in distinctive and bright plasmonic signatures near the slit visible by naked eye under an optical microscope. We demonstrate how this capability can be used for parallel measurement through a simple experiment in which the SPP propagation distance is extracted from a single microscope image of an illuminated array of nano-patterned slits on a metal surface. We also use optical microscopy to image the focal region of a plasmonic lens and obtain results consistent with a previously-reported results using near-field optical microscopy. Measurement of SPPs near a nano-slit using conventional and widely-available optical microscopy is an important step towards making nano-plasmonic device technology highly accessible and easy-to-use.

A low cost mobile phone dark-field microscope for nanoparticle-based quantitative studies.

PubMed

Sun, Dali; Hu, Tony Y

2018-01-15

Dark-field microscope (DFM) analysis of nanoparticle binding signal is highly useful for a variety of research and biomedical applications, but current applications for nanoparticle quantification rely on expensive DFM systems. The cost, size, limited robustness of these DFMs limits their utility for non-laboratory settings. Most nanoparticle analyses use high-magnification DFM images, which are labor intensive to acquire and subject to operator bias. Low-magnification DFM image capture is faster, but is subject to background from surface artifacts and debris, although image processing can partially compensate for background signal. We thus mated an LED light source, a dark-field condenser and a 20× objective lens with a mobile phone camera to create an inexpensive, portable and robust DFM system suitable for use in non-laboratory conditions. This proof-of-concept mobile DFM device weighs less than 400g and costs less than $2000, but analysis of images captured with this device reveal similar nanoparticle quantitation results to those acquired with a much larger and more expensive desktop DFMM system. Our results suggest that similar devices may be useful for quantification of stable, nanoparticle-based activity and quantitation assays in resource-limited areas where conventional assay approaches are not practical. Copyright © 2017 Elsevier B.V. All rights reserved.

Preliminary results of a computerized Placido disk surgical corneal topographer

NASA Astrophysics Data System (ADS)

Carvalho, Luis A.; Tonissi, S. A.; Castro, Jarbas C.

1999-06-01

We have developed a novel instrument for computerized corneal topography during surgery. The instrument measures a region of approximately 7 mm in diameter, providing the surgeon with precise values of power and astigmatism. The system is based on a Placido Disc projecting system, which is attached to the objective lens of the surgical microscope. The Placido Disc pattern is reflected by a 50% beam splitter attached to the body of the microscope. At the beam splitter we installed our home-made adaptor and a CCD monochromatic high resolution camera. A high quality frame grabber is installed on a PC and images are digitized at a 480x640 resolution. Algorithms based on image processing techniques were implemented for edge detection of pattern. Calibrating curves based on 4 spherical surfaces were generated and approximately 3600 points were calculated for each exam. Preliminary measurements on 10 healthy corneas were compared with the measurements made on an EyeSys Corneal Topographer. Mean deviation was 0.05 for radius of curvature, 0.24 D for power and 5 degrees for cylinder. This system, with some improvements, may be successfully used to diminish high post surgical astigmatisms in surgeries such as cataract and corneal transplant. This system could also be used to gather preoperative data in corneal topography assisted LASIK.

Evaluation of the use of strobe lights in the red lens of traffic signals : technical assistance report.

DOT National Transportation Integrated Search

1994-11-01

The objective of this study was to evaluate the effectiveness of using strobe lights in the red lens of traffic signals and, if appropriate, to recommend guidelines for their use. Strobe lights are used as a supplement to the red lens to draw the att...

Mitochondrial "movement" and lens optics following oxidative stress from UV-B irradiation: cultured bovine lenses and human retinal pigment epithelial cells (ARPE-19) as examples.

PubMed

Bantseev, Vladimir; Youn, Hyun-Yi

2006-12-01

Mitochondria provide energy generated by oxidative phosphorylation and at the same time play a central role in apoptosis and aging. As a byproduct of respiration, the electron transport chain is known to be the major intracellular site for the generation of reactive oxygen species (ROS). Exposure to solar and occupational ultraviolet (UV) radiation, and thus production of ROS and subsequent cell death, has been implicated in a large spectrum of skin and ocular pathologies, including cataract. Retinal pigment epithelial cell apoptosis generates photoreceptor dysfunction and ultimately visual impairment. The purpose of this article was to characterize in vitro changes following oxidative stress with UV-B radiation in (a) ocular lens optics and cellular function in terms of mitochondrial dynamics of bovine lens epithelium and superficial cortical fiber cells and (b) human retinal pigment epithelial (ARPE-19) cells. Cultured bovine lenses and confluent cultures of ARPE-19 cells were irradiated with broadband UV-B radiation at energy levels of 0.5 and 1.0 J/cm(2). Lens optical function (spherical aberration) was monitored daily up to 14 days using an automated laser scanning system that was developed at the University of Waterloo. This system consists of a single collimated scanning helium-neon laser source that projects a thin (0.05 mm) laser beam onto a plain mirror mounted at 45 degrees on a carriage assembly. This mirror reflects the laser beam directly up through the scanner table surface and through the lens under examination. A digital camera captures the actual position and slope of the laser beam at each step. When all steps have been made, the captured data for each step position is used to calculate the back vertex distance for each position and the difference in that measurement between beams. To investigate mitochondrial movement, the mitochondria-specific fluorescent dye Rhodamine 123 was used. Time series were acquired with a Zeiss 510 (configuration Meta 18) confocal laser scanning microscope equipped with an inverted Axiovert 200 M microscope and 40-x water-immersion C-Apochromat objective (NA 1.2). The optical analysis showed energy level-dependent increases in back vertex distance variability (loss of sharp focus) from 0.39 +/- 0.04 mm (control, n = 11) to 1.63 +/- 0.33 mm (1.0 J/cm(2), n = 10) and 0.63 +/- 0.13 mm (0.5 J/cm(2), n = 9). Confocal laser scanning microscopy analysis of both bovine lenses and ARPE-19 cells showed that following treatment at 0.5 J/cm(2) the mitochondria stopped moving immediately whereas at 1.0 J/cm(2) not only did the mitochondria stop moving, but fragmentation and swelling was seen. Untreated control tissue exhibited up to 15 microm/min of movement of the mitochondria. This could represent normal morphological change, presumably allowing energy transmission across the cell from regions of low to regions of high ATP demand. Lack of mitochondrial movement, fragmentation, and swelling of mitochondria may represent early morphological changes following oxidative stress that may lead to activation of caspase-mediated apoptotic pathways.

Progress toward an aberration-corrected low energy electron microscope for DNA sequencing and surface analysis.

PubMed

Mankos, Marian; Shadman, Khashayar; N'diaye, Alpha T; Schmid, Andreas K; Persson, Henrik H J; Davis, Ronald W

2012-11-01

Monochromatic, aberration-corrected, dual-beam low energy electron microscopy (MAD-LEEM) is a novel imaging technique aimed at high resolution imaging of macromolecules, nanoparticles, and surfaces. MAD-LEEM combines three innovative electron-optical concepts in a single tool: a monochromator, a mirror aberration corrector, and dual electron beam illumination. The monochromator reduces the energy spread of the illuminating electron beam, which significantly improves spectroscopic and spatial resolution. The aberration corrector is needed to achieve subnanometer resolution at landing energies of a few hundred electronvolts. The dual flood illumination approach eliminates charging effects generated when a conventional, single-beam LEEM is used to image insulating specimens. The low landing energy of electrons in the range of 0 to a few hundred electronvolts is also critical for avoiding radiation damage, as high energy electrons with kilo-electron-volt kinetic energies cause irreversible damage to many specimens, in particular biological molecules. The performance of the key electron-optical components of MAD-LEEM, the aberration corrector combined with the objective lens and a magnetic beam separator, was simulated. Initial results indicate that an electrostatic electron mirror has negative spherical and chromatic aberration coefficients that can be tuned over a large parameter range. The negative aberrations generated by the electron mirror can be used to compensate the aberrations of the LEEM objective lens for a range of electron energies and provide a path to achieving subnanometer spatial resolution. First experimental results on characterizing DNA molecules immobilized on Au substrates in a LEEM are presented. Images obtained in a spin-polarized LEEM demonstrate that high contrast is achievable at low electron energies in the range of 1-10 eV and show that small changes in landing energy have a strong impact on the achievable contrast. The MAD-LEEM approach promises to significantly improve the performance of a LEEM for a wide range of applications in the biosciences, material sciences, and nanotechnology where nanometer scale resolution and analytical capabilities are required. In particular, the microscope has the potential of delivering images of unlabeled DNA strands with nucleotide-specific contrast. This simplifies specimen preparation and significantly eases the computational complexity needed to assemble the DNA sequence from individual reads.

Progress toward an aberration-corrected low energy electron microscope for DNA sequencing and surface analysis

PubMed Central

Mankos, Marian; Shadman, Khashayar; N'Diaye, Alpha T.; Schmid, Andreas K.; Persson, Henrik H. J.; Davis, Ronald W.

2012-01-01

Monochromatic, aberration-corrected, dual-beam low energy electron microscopy (MAD-LEEM) is a novel imaging technique aimed at high resolution imaging of macromolecules, nanoparticles, and surfaces. MAD-LEEM combines three innovative electron–optical concepts in a single tool: a monochromator, a mirror aberration corrector, and dual electron beam illumination. The monochromator reduces the energy spread of the illuminating electron beam, which significantly improves spectroscopic and spatial resolution. The aberration corrector is needed to achieve subnanometer resolution at landing energies of a few hundred electronvolts. The dual flood illumination approach eliminates charging effects generated when a conventional, single-beam LEEM is used to image insulating specimens. The low landing energy of electrons in the range of 0 to a few hundred electronvolts is also critical for avoiding radiation damage, as high energy electrons with kilo-electron-volt kinetic energies cause irreversible damage to many specimens, in particular biological molecules. The performance of the key electron–optical components of MAD-LEEM, the aberration corrector combined with the objective lens and a magnetic beam separator, was simulated. Initial results indicate that an electrostatic electron mirror has negative spherical and chromatic aberration coefficients that can be tuned over a large parameter range. The negative aberrations generated by the electron mirror can be used to compensate the aberrations of the LEEM objective lens for a range of electron energies and provide a path to achieving subnanometer spatial resolution. First experimental results on characterizing DNA molecules immobilized on Au substrates in a LEEM are presented. Images obtained in a spin-polarized LEEM demonstrate that high contrast is achievable at low electron energies in the range of 1–10 eV and show that small changes in landing energy have a strong impact on the achievable contrast. The MAD-LEEM approach promises to significantly improve the performance of a LEEM for a wide range of applications in the biosciences, material sciences, and nanotechnology where nanometer scale resolution and analytical capabilities are required. In particular, the microscope has the potential of delivering images of unlabeled DNA strands with nucleotide-specific contrast. This simplifies specimen preparation and significantly eases the computational complexity needed to assemble the DNA sequence from individual reads. PMID:23847748

Nasendoscopy: an analysis of measurement uncertainties.

PubMed

Gilleard, Onur; Sommerlad, Brian; Sell, Debbie; Ghanem, Ali; Birch, Malcolm

2013-05-01

Objective : The purpose of this study was to analyze the optical characteristics of two different nasendoscopes used to assess velopharyngeal insufficiency and to quantify the measurement uncertainties that will occur in a typical set of clinical data. Design : The magnification and barrel distortion associated with nasendoscopy was estimated by using computer software to analyze the apparent dimensions of a spatially calibrated test object at varying object-lens distances. In addition, a method of semiquantitative analysis of velopharyngeal closure using nasendoscopy and computer software is described. To calculate the reliability of this method, 10 nasendoscopy examinations were analyzed two times by three separate operators. The measure of intraoperator and interoperator agreement was evaluated using Pearson's r correlation coefficient. Results : Over an object lens distance of 9 mm, magnification caused the visualized dimensions of the test object to increase by 80%. In addition, dimensions of objects visualized in the far-peripheral field of the nasendoscopic examinations appeared approximately 40% smaller than those visualized in the central field. Using computer software to analyze velopharyngeal closure, the mean correlation coefficient for intrarater reliability was .94 and for interrater reliability was .90. Conclusion : Using a custom-designed apparatus, the effect object-lens distance has on the magnification of nasendoscopic images has been quantified. Barrel distortion has also been quantified and was found to be independent of object-lens distance. Using computer software to analyze clinical images, the intraoperator and interoperator correlation appears to show that ratio-metric measurements are reliable.

Stimulated penetrating keratoplasty using real-time virtual intraoperative surgical optical coherence tomography

PubMed Central

Lee, Changho; Kim, Kyungun; Han, Seunghoon; Kim, Sehui; Lee, Jun Hoon; Kim, Hong kyun; Kim, Chulhong; Jung, Woonggyu; Kim, Jeehyun

2014-01-01

Abstract. An intraoperative surgical microscope is an essential tool in a neuro- or ophthalmological surgical environment. Yet, it has an inherent limitation to classify subsurface information because it only provides the surface images. To compensate for and assist in this problem, combining the surgical microscope with optical coherence tomography (OCT) has been adapted. We developed a real-time virtual intraoperative surgical OCT (VISOCT) system by adapting a spectral-domain OCT scanner with a commercial surgical microscope. Thanks to our custom-made beam splitting and image display subsystems, the OCT images and microscopic images are simultaneously visualized through an ocular lens or the eyepiece of the microscope. This improvement helps surgeons to focus on the operation without distraction to view OCT images on another separate display. Moreover, displaying the OCT live images on the eyepiece helps surgeon’s depth perception during the surgeries. Finally, we successfully processed stimulated penetrating keratoplasty in live rabbits. We believe that these technical achievements are crucial to enhance the usability of the VISOCT system in a real surgical operating condition. PMID:24604471

Patient Compliance During Contact Lens Wear: Perceptions, Awareness, and Behavior

PubMed Central

Bui, Thai H.; Cavanagh, H. Dwight; Robertson, Danielle M.

2011-01-01

Objectives Patient noncompliance with recommended hygienic practices in contact lens wear is often considered a significant risk factor for microbial keratitis and adverse contact lens–related events. Despite advancements in lens materials and care solutions, noncompliant behavior continues to hinder efforts to maximize contact lens safety. The objective of this pilot study was to assess the relationship between perceived and actual compliance with awareness of risk and behavior. Methods One hundred sixty-two established contact lens wearers were sequentially evaluated after their routine contact lens examination at the Optometry Clinic at the University of Texas Southwestern Medical Center at Dallas, TX. Each patient was questioned by a single trained interviewer regarding his or her lens care practices and knowledge of risk factors associated with lens wear. Results Eighty-six percent of patients believed they were compliant with lens wear and care practices; 14% identified themselves as noncompliant. Using a scoring model, 32% demonstrated good compliance, 44% exhibited average compliance, and 24% were noncompliant; age was a significant factor (P = 0.020). Only 34% of patients who perceived themselves as compliant exhibited a good level of compliance (P<0.001). Eighty percent of patients reported an awareness of risk factors, but awareness did not influence negative behavior. Replacing the lens case was the only behavior associated with a positive history for having experienced a prior contact lens–related complication (P = 0.002). Conclusions Perceived compliance is not an indicator for appropriate patient behavior. A large proportion of patients remain noncompliant despite awareness of risk. Education alone is not a sufficient strategy to improve behavior; newer approaches aimed at improving compliance with lens care practices are urgently needed. PMID:20935569

Objective measurement of accommodative biometric changes using ultrasound biomicroscopy

PubMed Central

Ramasubramanian, Viswanathan; Glasser, Adrian

2015-01-01

PURPOSE To demonstrate that ultrasound biomicroscopy (UBM) can be used for objective quantitative measurements of anterior segment accommodative changes. SETTING College of Optometry, University of Houston, Houston, Texas, USA. DESIGN Prospective cross-sectional study. METHODS Anterior segment biometric changes in response to 0 to 6.0 diopters (D) of accommodative stimuli in 1.0 D steps were measured in eyes of human subjects aged 21 to 36 years. Imaging was performed in the left eye using a 35 MHz UBM (Vumax) and an A-scan ultrasound (A-5500) while the right eye viewed the accommodative stimuli. An automated Matlab image-analysis program was developed to measure the biometry parameters from the UBM images. RESULTS The UBM-measured accommodative changes in anterior chamber depth (ACD), lens thickness, anterior lens radius of curvature, posterior lens radius of curvature, and anterior segment length were statistically significantly (P < .0001) linearly correlated with accommodative stimulus amplitudes. Standard deviations of the UBM-measured parameters were independent of the accommodative stimulus demands (ACD 0.0176 mm, lens thickness 0.0294 mm, anterior lens radius of curvature 0.3350 mm, posterior lens radius of curvature 0.1580 mm, and anterior segment length 0.0340 mm). The mean difference between the A-scan and UBM measurements was −0.070 mm for ACD and 0.166 mm for lens thickness. CONCLUSIONS Accommodating phakic eyes imaged using UBM allowed visualization of the accommodative response, and automated image analysis of the UBM images allowed reliable, objective, quantitative measurements of the accommodative intraocular biometric changes. PMID:25804579

Real-time Optical Coherence Tomography Incorporated in the Operating Microscope during Cataract Surgery.

PubMed

Almutlak, Mohammed A; Aloniazan, Turki; May, William

2017-01-01

A 55-year-old male presented with reduced vision due to senile cataract. The patient consented to undergo real-time intraoperative anterior segment-optical coherence tomography (AS-OCT) during phacoemulsification with intraocular lens (IOL) implantation. Images were captured at various points during the surgery. The use of AS-OCT incorporated into the surgical microscope was evaluated as an adjunct to cataract surgery. We were able to successfully evaluate, in real-time, wound architecture, the attachment of Descemet's membrane, the posterior capsule, and IOL position. Real-time AS-OCT can be used to proactively address potential complications and verify IOL placement intraoperatively.

A Comparative Study Between Smartphone-Based Microscopy and Conventional Light Microscopy in 1021 Dermatopathology Specimens.

PubMed

Jahan-Tigh, Richard R; Chinn, Garrett M; Rapini, Ronald P

2016-01-01

The incorporation of high-resolution cameras into smartphones has allowed for a variety of medical applications including the use of lens attachments that provide telescopic, macroscopic, and dermatoscopic data, but the feasibility and performance characteristics of such a platform for use in dermatopathology have not been described. To determine the diagnostic performance of a smartphone microscope compared to traditional light microscopy in dermatopathology specimens. A simple smartphone microscope constructed with a 3-mm ball lens was used to prospectively evaluate 1021 consecutive dermatopathology cases in a blinded fashion. Referred, consecutive specimens from the community were evaluated at a single university hospital. The performance characteristics of the smartphone platform were calculated by using conventional light microscopy as the gold standard. The sensitivity and specificity for the diagnosis of melanoma, nonmelanoma skin cancers, and other miscellaneous conditions by the phone microscopy platform, as compared with traditional light microscopy, were calculated. For basal cell carcinoma (n = 136), the sensitivity and specificity of smartphone microscopy were 95.6% and 98.1%, respectively. The sensitivity and specificity for squamous cell carcinoma (n = 94) were 89.4% and 97.3%, respectively. The lowest sensitivity was found in melanoma (n = 15) at 60%, although the specificity was high at 99.1%. The accuracy of diagnosis of inflammatory conditions and other neoplasms was variable. Mobile phone-based microscopy has excellent performance characteristics for the inexpensive diagnosis of nonmelanoma skin cancers in a setting where a traditional microscope is not available.

Exploiting chromatic aberration to spectrally encode depth in reflectance confocal microscopy

NASA Astrophysics Data System (ADS)

Carrasco-Zevallos, Oscar; Shelton, Ryan L.; Olsovsky, Cory; Saldua, Meagan; Applegate, Brian E.; Maitland, Kristen C.

2011-06-01

We present chromatic confocal microscopy as a technique to axially scan the sample by spectrally encoding depth information to avoid mechanical scanning of the lens or sample. We have achieved an 800 μm focal shift over a range of 680-1080 nm using a hyperchromat lens as the imaging lens. A more complex system that incorporates a water immersion objective to improve axial resolution was built and tested. We determined that increasing objective magnification decreases chromatic shift while improving axial resolution. Furthermore, collimating after the hyperchromat at longer wavelengths yields an increase in focal shift.

Lens fiber organization in four avian species: a scanning electron microscopic study.

PubMed

Willekens, B; Vrensen, G

1985-01-01

The three-dimensional organization of the eye lenses of the chicken, the canary, the song-thrush and the kestrel was studied using light and scanning electron microscopy. The lenses of birds are characterized by the presence of two distinct compartments: the annular pad and the main lens body, separated by a cavum lenticuli. The annular pad fibers had a hexagonal circumference all contained a round nucleus and except for the canary were smooth-surfaced and lacking anchoring devices. In the canary, however, the annular pad fibers were studded with edge protrusions and ball-and-socket junctions. The semicircular main lens body fibers of all four species were studded with ball-and-socket junctions and edge protrusions. In contrast with mammals these anchoring devices were present throughout the lens up to the embryonal nucleus. Superficially the main lens body fibers were extremely flat. Additionally membrane elevations and depressions and globular elements were found on these central fibers in three species, the kestrel being the exception. At the transition between annular pad and main lens body the fibers turned their course and the nuclei became oval and disappeared in the deeper aspect of the main lens body. The cavum lenticuli was filled with globules tied off from the annular pad fibers. It seems attractive to assume that the presence of a separated annular pad, a cavum lenticuli filled with globular elements, the extreme flatness of the superficial central fibers and the studding of these central fibers with anchoring devices up to the embryonal nucleus are morphological expressions of the mouldability of the bird's eye lenses and consequently would explain their efficient accommodative mechanism including formation of a lenticonus. The presence of nuclei in the annular pad fibers and their typical change at the transitional zone between annular pad and main lens body are suggestive for a two-phased differentiation in bird's lens fibers: differentiation of the germinative epithelial cells to annular pad fibers which migrate to the main lens body after which they differentiate further to main lens body fibers.

Development of a Whole Slide Imaging System on Smartphones and Evaluation With Frozen Section Samples.

PubMed

Yu, Hong; Gao, Feng; Jiang, Liren; Ma, Shuoxin

2017-09-15

The aim was to develop scalable Whole Slide Imaging (sWSI), a WSI system based on mainstream smartphones coupled with regular optical microscopes. This ultra-low-cost solution should offer diagnostic-ready imaging quality on par with standalone scanners, supporting both oil and dry objective lenses of different magnifications, and reasonably high throughput. These performance metrics should be evaluated by expert pathologists and match those of high-end scanners. The aim was to develop scalable Whole Slide Imaging (sWSI), a whole slide imaging system based on smartphones coupled with optical microscopes. This ultra-low-cost solution should offer diagnostic-ready imaging quality on par with standalone scanners, supporting both oil and dry object lens of different magnification. All performance metrics should be evaluated by expert pathologists and match those of high-end scanners. In the sWSI design, the digitization process is split asynchronously between light-weight clients on smartphones and powerful cloud servers. The client apps automatically capture FoVs at up to 12-megapixel resolution and process them in real-time to track the operation of users, then give instant feedback of guidance. The servers first restitch each pair of FoVs, then automatically correct the unknown nonlinear distortion introduced by the lens of the smartphone on the fly, based on pair-wise stitching, before finally combining all FoVs into one gigapixel VS for each scan. These VSs can be viewed using Internet browsers anywhere. In the evaluation experiment, 100 frozen section slides from patients randomly selected among in-patients of the participating hospital were scanned by both a high-end Leica scanner and sWSI. All VSs were examined by senior pathologists whose diagnoses were compared against those made using optical microscopy as ground truth to evaluate the image quality. The sWSI system is developed for both Android and iPhone smartphones and is currently being offered to the public. The image quality is reliable and throughput is approximately 1 FoV per second, yielding a 15-by-15 mm slide under 20X object lens in approximately 30-35 minutes, with little training required for the operator. The expected cost for setup is approximately US $100 and scanning each slide costs between US $1 and $10, making sWSI highly cost-effective for infrequent or low-throughput usage. In the clinical evaluation of sample-wise diagnostic reliability, average accuracy scores achieved by sWSI-scan-based diagnoses were as follows: 0.78 for breast, 0.88 for uterine corpus, 0.68 for thyroid, and 0.50 for lung samples. The respective low-sensitivity rates were 0.05, 0.05, 0.13, and 0.25 while the respective low-specificity rates were 0.18, 0.08, 0.20, and 0.25. The participating pathologists agreed that the overall quality of sWSI was generally on par with that produced by high-end scanners, and did not affect diagnosis in most cases. Pathologists confirmed that sWSI is reliable enough for standard diagnoses of most tissue categories, while it can be used for quick screening of difficult cases. As an ultra-low-cost alternative to whole slide scanners, diagnosis-ready VS quality and robustness for commercial usage is achieved in the sWSI solution. Operated on main-stream smartphones installed on normal optical microscopes, sWSI readily offers affordable and reliable WSI to resource-limited or infrequent clinical users. ©Hong Yu, Feng Gao, Liren Jiang, Shuoxin Ma. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 15.09.2017.

Expression of the sodium potassium chloride cotransporter (NKCC1) and sodium chloride cotransporter (NCC) and their effects on rat lens transparency.

PubMed

Chee, K N; Vorontsova, I; Lim, J C; Kistler, J; Donaldson, P J

2010-05-04

To characterize the expression patterns of the Na+-K+-Cl(-) cotransporter (NKCC) 1 and NKCC2, and the Na+-Cl(-) cotransporter (NCC) in the rat lens and to determine if they play a role in regulating lens volume and transparency. RT-PCR was performed on RNA extracted from fiber cells to identify sodium dependent cotransporters expressed in the rat lens. Western blotting and immunohistochemistry, using NKCC1, NKCC2, and NCC antibodies, were used to verify expression at the protein level and to localize transporter expression. Organ cultured rat lenses were incubated in Artificial Aqueous Humor (AAH) of varying osmolarities or isotonic AAH that contained either the NKCC specific inhibitor bumetanide, or the NCC specific inhibitor thiazide for up to 18 h. Lens transparency was monitored with dark field microscopy, while tissue morphology and antibody labeling patterns were recorded using a confocal microscope. Molecular experiments showed that NKCC1 and NCC were expressed in the lens at both the transcript and protein levels, but NKCC2 was not. Immunohistochemistry showed that both NKCC1 and NCC were expressed in the lens cortex, but NCC expression was also found in the lens core. In the lens cortex the majority of labeling for both transporters was cytoplasmic in nature, while in the lens core, NCC labeling was associated with the membrane. Exposure of lenses to either hypotonic or hypertonic AAH had no noticeable effects on the predominantly cytoplasmic location of either transporter in the lens cortex. Incubation of lenses in isotonic AAH plus the NKCC inhibitor bumetanide for 18 h induced a cortical opacity that was initiated by a shrinkage of peripheral fiber cells and the dilation of the extracellular space between fiber cells in a deeper zone located some approximately 150 microm in from the capsule. In contrast, lenses incubated in isotonic AAH and the NCC inhibitor thiazide maintained both their transparency and their regular fiber cell morphology. We have confirmed the expression of NKCC1 in the rat lens and report for the first time the expression of NCC in lens fiber cells. The expression patterns of the two transporters and the differential effects of their specific inhibitors on fiber cell morphology indicate that these transporters play distinct roles in the lens. NKCC1 appears to mediate ion influx in the lens cortex while NCC may play a role in the lens nucleus.

Study on real-time images compounded using spatial light modulator

NASA Astrophysics Data System (ADS)

Xu, Jin; Chen, Zhebo; Ni, Xuxiang; Lu, Zukang

2007-01-01

Image compounded technology is often used on film and its facture. In common, image compounded use image processing arithmetic, get useful object, details, background or some other things from the images firstly, then compounding all these information into one image. When using this method, the film system needs a powerful processor, for the process function is very complex, we get the compounded image for a few time delay. In this paper, we introduce a new method of image real-time compounded, use this method, we can do image composite at the same time with movie shot. The whole system is made up of two camera-lens, spatial light modulator array and image sensor. In system, the spatial light modulator could be liquid crystal display (LCD), liquid crystal on silicon (LCoS), thin film transistor liquid crystal display (TFTLCD), Deformable Micro-mirror Device (DMD), and so on. Firstly, one camera-lens images the object on the spatial light modulator's panel, we call this camera-lens as first image lens. Secondly, we output an image to the panel of spatial light modulator. Then, the image of the object and image that output by spatial light modulator will be spatial compounded on the panel of spatial light modulator. Thirdly, the other camera-lens images the compounded image to the image sensor, and we call this camera-lens as second image lens. After these three steps, we will gain the compound images by image sensor. For the spatial light modulator could output the image continuously, then the image will be compounding continuously too, and the compounding procedure is completed in real-time. When using this method to compounding image, if we will put real object into invented background, we can output the invented background scene on the spatial light modulator, and the real object will be imaged by first image lens. Then, we get the compounded images by image sensor in real time. The same way, if we will put real background to an invented object, we can output the invented object on the spatial light modulator and the real background will be imaged by first image lens. Then, we can also get the compounded images by image sensor real time. Commonly, most spatial light modulator only can do modulate light intensity, so we can only do compounding BW images if use only one panel which without color filter. If we will get colorful compounded image, we need use the system like three spatial light modulator panel projection. In the paper, the system's optical system framework we will give out. In all experiment, the spatial light modulator used liquid crystal on silicon (LCoS). At the end of the paper, some original pictures and compounded pictures will be given on it. Although the system has a few shortcomings, we can conclude that, using this system to compounding images has no delay to do mathematic compounding process, it is a really real time images compounding system.

Assessment of fresh breast tissue specimens with confocal strip-mosaicking microscopy in an emulated pathology setting (Conference Presentation)

NASA Astrophysics Data System (ADS)

Abeytunge, Sanjeewa; Larson, Bjorg A.; Peterson, Gary; Rajadhyaksha, Milind; Murray, Melissa

2017-02-01

Confocal microscopy is in clinical use to diagnose skin cancers in the United States and in Europe. Potentially, this technology may provide bed-side pathology in breast cancer surgery during tumor removal. Initial studies have described major findings of invasive breast cancers as seen on fluorescence confocal microscopy. In many of these studies the region of interest (ROI) used in the analysis was user-selected and small (typically 15 square-mm). Although these important findings open exploration into rapid pathology, further development and implementation in a surgical setting will require examination of large specimens in a blinded fashion that will address the needs of typical surgical settings. In post surgery pathology viewing, pathologists inspect the entire pathology section with a low (2X) magnification objective lens initially and then zoomed in to ROIs with higher magnification lenses (10X to 40X) magnifications to further investigate suspected regions. In this study we explore the possibility of implementation in a typical surgical setting with a new microscope, termed confocal strip-mosaicking microscope (CSM microscope), which images an area of 400 square-mm (2 cm x 2 cm) of tissue with cellular level resolution in 10 minutes. CSM images of 34 human breast tissue specimens from 18 patients were blindly analyzed by a board-certified pathologist and correlated with the corresponding standard fixed histopathology. Invasive tumors and benign tissue were clearly identified in CSM images. Thirty specimens were concordant for images-to-histopathology correlation while four were discordant. Preliminary results from on-going work to molecularly target tumor margin will also be presented.

Versatile microfluidic total internal reflection (TIR)-based devices: application to microbeads velocity measurement and single molecule detection with upright and inverted microscope.

PubMed

Le, Nam Cao Hoai; Yokokawa, Ryuji; Dao, Dzung Viet; Nguyen, Thien Duy; Wells, John C; Sugiyama, Susumu

2009-01-21

A poly(dimethylsiloxane) (PDMS) chip for Total Internal Reflection (TIR)-based imaging and detection has been developed using Si bulk micromachining and PDMS casting. In this paper, we report the applications of the chip on both inverted and upright fluorescent microscopes and confirm that two types of sample delivery platforms, PDMS microchannel and glass microchannel, can be easily integrated depending on the magnification of an objective lens needed to visualize a sample. Although any device configuration can be achievable, here we performed two experiments to demonstrate the versatility of the microfluidic TIR-based devices. The first experiment was velocity measurement of Nile red microbeads with nominal diameter of 500 nm in a pressure-driven flow. The time-sequenced fluorescent images of microbeads, illuminated by an evanescent field, were cross-correlated by a Particle Image Velocimetry (PIV) program to obtain near-wall velocity field of the microbeads at various flow rates from 500 nl/min to 3000 nl/min. We then evaluated the capabilities of the device for Single Molecule Detection (SMD) of fluorescently labeled DNA molecules from 30 bp to 48.5 kbp and confirm that DNA molecules as short as 1105 bp were detectable. Our versatile, integrated device could provide low-cost and fast accessibility to Total Internal Reflection Fluorescent Microscopy (TIRFM) on both conventional upright and inverted microscopes. It could also be a useful component in a Micro-Total Analysis System (micro-TAS) to analyze nanoparticles or biomolecules near-wall transport or motion.

In Vivo Near Infrared Virtual Intraoperative Surgical Photoacoustic Optical Coherence Tomography

PubMed Central

Lee, Donghyun; Lee, Changho; Kim, Sehui; Zhou, Qifa; Kim, Jeehyun; Kim, Chulhong

2016-01-01

Since its first implementation in otolaryngological surgery nearly a century ago, the surgical microscope has improved the accuracy and the safety of microsurgeries. However, the microscope shows only a magnified surface view of the surgical region. To overcome this limitation, either optical coherence tomography (OCT) or photoacoustic microscopy (PAM) has been independently combined with conventional surgical microscope. Herein, we present a near-infrared virtual intraoperative photoacoustic optical coherence tomography (NIR-VISPAOCT) system that combines both PAM and OCT with a conventional surgical microscope. Using optical scattering and absorption, the NIR-VISPAOCT system simultaneously provides surgeons with real-time comprehensive biological information such as tumor margins, tissue structure, and a magnified view of the region of interest. Moreover, by utilizing a miniaturized beam projector, it can back-project 2D cross-sectional PAM and OCT images onto the microscopic view plane. In this way, both microscopic and cross-sectional PAM and OCT images are concurrently displayed on the ocular lens of the microscope. To verify the usability of the NIR-VISPAOCT system, we demonstrate simulated surgeries, including in vivo image-guided melanoma resection surgery and in vivo needle injection of carbon particles into a mouse thigh. The proposed NIR-VISPAOCT system has potential applications in neurosurgery, ophthalmological surgery, and other microsurgeries. PMID:27731390

A Neptune-mass Free-floating Planet Candidate Discovered by Microlensing Surveys

NASA Astrophysics Data System (ADS)

Mróz, Przemek; Ryu, Y.-H.; Skowron, J.; Udalski, A.; Gould, A.; Szymański, M. K.; Soszyński, I.; Poleski, R.; Pietrukowicz, P.; Kozłowski, S.; Pawlak, M.; Ulaczyk, K.; OGLE Collaboration; Albrow, M. D.; Chung, S.-J.; Jung, Y. K.; Han, C.; Hwang, K.-H.; Shin, I.-G.; Yee, J. C.; Zhu, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.; KMTNet Collaboration

2018-03-01

Current microlensing surveys are sensitive to free-floating planets down to Earth-mass objects. All published microlensing events attributed to unbound planets were identified based on their short timescale (below two days), but lacked an angular Einstein radius measurement (and hence lacked a significant constraint on the lens mass). Here, we present the discovery of a Neptune-mass free-floating planet candidate in the ultrashort (t E = 0.320 ± 0.003 days) microlensing event OGLE-2016-BLG-1540. The event exhibited strong finite-source effects, which allowed us to measure its angular Einstein radius of θ E = 9.2 ± 0.5 μas. There remains, however, a degeneracy between the lens mass and distance. The combination of the source proper motion and source-lens relative proper motion measurements favors a Neptune-mass lens located in the Galactic disk. However, we cannot rule out that the lens is a Saturn-mass object belonging to the bulge population. We exclude stellar companions up to ∼15 au.

Cascaded plasmonic superlens for far-field imaging with magnification at visible wavelength.

PubMed

Li, Huiyu; Fu, Liwei; Frenner, Karsten; Osten, Wolfgang

2018-04-16

We experimentally demonstrate a novel design of a cascaded plasmonic superlens, which can directly image subwavelength objects with magnification in the far field at visible wavelengths. The lens consists of two cascaded plasmonic slabs. One is a plasmonic metasurface used for near field coupling, and the other one is a planar plasmonic lens used for phase compensation and thus image magnification. First, we show numerical calculations about the performance of the lens. Based on these results we then describe the fabrication of both sub-structures and their combination. Finally, we demonstrate imaging performance of the lens for a subwavelength double-slit object as an example. The fabricated superlens exhibits a lateral resolution down to 180 nm at a wavelength of 640 nm, as predicted by numerical calculations. This might be the first experimental demonstration in which a planar plasmonic lens is employed for near-field image magnification. Our results could open a way for designing and fabricating novel miniaturized plasmonic superlenses in the future.

Near-infrared images of MG 1131+0456 with the W. M. Keck telescope: Another dusty gravitational lens?

NASA Technical Reports Server (NTRS)

Larkin, J. E.; Matthews, K.; Lawrence, C. R.; Graham, J. R.; Harrison, W.; Jernigan, G.; Lin, S.; Nelson, J.; Neugebauer, G.; Smith, G.

1994-01-01

Images of the gravitational lens system MG 1131+0456 taken with the near-infrared camera on the W. M. Keck telescope in the J and K(sub s) bands show that the infrared counterparts of the compact radio structure are exceedingly red, with J - K greater than 4.2 mag. The J image reveals only the lensing galaxy, while the K(sub s) image shows both the lens and the infrared counterparts of the compact radio components. After subtracting the lensing galaxy from the K(sub s) image, the position and orientation of the compact components agree with their radio counterparts. The broad-band spectrum and observed brightness of the lens suggest a giant galaxy at a redshift of approximately 0.75, while the color of the quasar images suggests significant extinction by dust in the lens. There is a significant excess of faint objects within 20 sec of MG 1131+0456. Depending on their mass and redshifts, these objects could complicate the lensing potential considerably.

VLT adaptive optics search for luminous substructures in the lens galaxy towards SDSS J0924+0219

NASA Astrophysics Data System (ADS)

Faure, C.; Sluse, D.; Cantale, N.; Tewes, M.; Courbin, F.; Durrer, P.; Meylan, G.

2011-12-01

The anomalous flux ratios between quasar images are suspected of being caused by substructures in lens galaxies. We present new deep and high-resolution H and Ks imaging of the strongly lensed quasar SDSS J0924+0219 obtained using the ESO VLT with adaptive optics and the laser guide star system. SDSS J0924+0219 is particularly interesting because the observed flux ratio between the quasar images vastly disagree with the predictions from smooth mass models. With our adaptive optics observations we find a luminous object, Object L, located ~0.3'' to the north of the lens galaxy, but we show that it cannot be responsible for the anomalous flux ratios. Object L as well as a luminous extension of the lens galaxy to the south are seen in the archival HST/ACS image in the F814W filter. This suggests that Object L is part of a bar in the lens galaxy, as also supported by the presence of a significant disk component in the light profile of the lens galaxy. Finally, we find no evidence of any other luminous substructure that may explain the quasar images flux ratios. However, owing to the persistence of the flux ratio anomaly over time (~7 years), a combination of microlensing and millilensing is the favorite explanation for the observations. Based on observations obtained with the ESO VLT at Paranal observatory (Prog ID 084.A-0762(A); PI: Meylan). Also based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with the CASTLES (Cfa-Arizona Space Telescope LEns Survey) survey (ID: 9744, PI: C. S. Kochanek).

A Field-Portable Cell Analyzer without a Microscope and Reagents.

PubMed

Seo, Dongmin; Oh, Sangwoo; Lee, Moonjin; Hwang, Yongha; Seo, Sungkyu

2017-12-29

This paper demonstrates a commercial-level field-portable lens-free cell analyzer called the NaviCell (No-stain and Automated Versatile Innovative cell analyzer) capable of automatically analyzing cell count and viability without employing an optical microscope and reagents. Based on the lens-free shadow imaging technique, the NaviCell (162 × 135 × 138 mm³ and 1.02 kg) has the advantage of providing analysis results with improved standard deviation between measurement results, owing to its large field of view. Importantly, the cell counting and viability testing can be analyzed without the use of any reagent, thereby simplifying the measurement procedure and reducing potential errors during sample preparation. In this study, the performance of the NaviCell for cell counting and viability testing was demonstrated using 13 and six cell lines, respectively. Based on the results of the hemocytometer ( de facto standard), the error rate (ER) and coefficient of variation (CV) of the NaviCell are approximately 3.27 and 2.16 times better than the commercial cell counter, respectively. The cell viability testing of the NaviCell also showed an ER and CV performance improvement of 5.09 and 1.8 times, respectively, demonstrating sufficient potential in the field of cell analysis.

Selected-zone dark-field electron microscopy.

NASA Technical Reports Server (NTRS)

Heinemann, K.; Poppa, H.

1972-01-01

Description of a new method which makes it possible to reduce drastically the resolution-limiting influence of chromatic aberration, and thus to obtain high-quality images, by selecting the image-forming electrons that have passed through a small annular zone of an objective lens. In addition, the manufacture of special objective-lens aperture diaphragms that are needed for this method is also described.

Design, assembly, and testing of a high-resolution relay lens used for holography with operation at both doubled and tripled Nd:YAG laser wavelengths

NASA Astrophysics Data System (ADS)

Malone, Robert M.; Capelle, Gene A.; Cox, Brian C.; Frogget, Brent C.; Grover, Mike; Kaufman, Morris I.; Pazuchanics, Peter; Sorenson, Danny S.; Stevens, Gerald D.; Tibbitts, Aric; Turley, William D.

2009-08-01

The design and assembly of a nine-element lens that achieves >2000 lp/mm resolution at a 355-nm wavelength (ultraviolet) has been completed. By adding a doublet to this lens system, operation at a 532-nm wavelength (green) with >1100 lp/mm resolution is achieved. This lens is used with high-power laser light to record holograms of fast-moving ejecta particles from a shocked metal surface located inside a test package. Part of the lens and the entire test package are under vacuum with a 1-cm air gap separation. Holograms have been recorded with both doubled and tripled Nd:YAG laser light. The UV operation is very sensitive to the package window's tilt. If this window is tilted by more than 0.1 degrees, the green operation performs with better resolution than that of the UV operation. The setup and alignment are performed with green light, but the dynamic recording can be done with either UV light or green light. A resolution plate can be temporarily placed inside the test package so that a television microscope located beyond the hologram position can archive images of resolution patterns that prove that the calibration wires, interference filter, holographic plate, and relay lenses are in their correct positions. Part of this lens is under vacuum, at the point where the laser illumination passes through a focus. Alignment and tolerancing of this high-resolution lens are presented. Resolution variation across the 12-mm field of view and throughout the 5-mm depth of field is discussed for both wavelengths.

Increased numbers of Demodex in contact lens wearers.

PubMed

Jalbert, Isabelle; Rejab, Shazana

2015-06-01

The aim of this study was to determine if Demodex infestation is more frequent in contact lens wearers than in nonwearers. Secondary aims were to evaluate the effects of Demodex on the ocular surface (symptoms and signs) and to evaluate the ability of confocal laser scanning microscopy to detect and quantify the Demodex infestation compared with the conventional light microscopic technique. Forty Asian female participants (20 nonwearers, 20 lens wearers) with a mean (± SD) age of 27 (± 9) years were recruited. Ocular comfort scores (Ocular Surface Disease Index, Ocular Comfort Index, and Dry Eye Questionnaire), vital staining (corneal, conjunctival, and lid wiper), tear osmolarity, tear breakup time, and meibomian gland evaluation were evaluated. Demodex was detected using in vivo confocal microscopy and conventional light microscopy. The number of Demodex was higher in lens wearers than in nonwearers (7.6 [± 5.8] vs. 5.0 [± 3.1]; p = 0.02). Demodex was observed in a large majority (90%) of lens wearers and in 65% of nonwearers using confocal microscopy (p = 0.06). The detection rate was lower in both groups using conventional light microscopy (p = 0.003) where Demodex could only be confirmed in 70% and 60% of lens wearers and nonwearers, respectively. The number of Demodex tended to increase with age (ρ = 0.28, p = 0.08), but Demodex did not appear to affect ocular comfort or any clinical signs (p > 0.05). Contact lens wearers harbor Demodex as frequently as nonwearers and in higher numbers, which is best detected using in vivo confocal microscopy. The significance of these findings is uncertain because no associations were found with any symptoms and signs of dry eye disease.

Microscopy using source and detector arrays

NASA Astrophysics Data System (ADS)

Sheppard, Colin J. R.; Castello, Marco; Vicidomini, Giuseppe; Duocastella, Martí; Diaspro, Alberto

2016-03-01

There are basically two types of microscope, which we call conventional and scanning. The former type is a full-field imaging system. In the latter type, the object is illuminated with a probe beam, and a signal detected. We can generalize the probe to a patterned illumination. Similarly we can generalize the detection to a patterned detection. Combining these we get a range of different modalities: confocal microscopy, structured illumination (with full-field imaging), spinning disk (with multiple illumination points), and so on. The combination allows the spatial frequency bandwidth of the system to be doubled. In general we can record a four dimensional (4D) image of a 2D object (or a 6D image from a 3D object, using an acoustic tuneable lens). The optimum way to directly reconstruct the resulting image is by image scanning microscopy (ISM). But the 4D image is highly redundant, so deconvolution-based approaches are also relevant. ISM can be performed in fluorescence, bright field or interference microscopy. Several different implementations have been described, with associated advantages and disadvantages. In two-photon microscopy, the illumination and detection point spread functions are very different. This is also the case when using pupil filters or when there is a large Stokes shift.

Micro-Ball-Lens Optical Switch Driven by SMA Actuator

NASA Technical Reports Server (NTRS)

Yang, Eui-Hyeok

2003-01-01

The figure is a simplified cross section of a microscopic optical switch that was partially developed at the time of reporting the information for this article. In a fully developed version, light would be coupled from an input optical fiber to one of two side-by-side output optical fibers. The optical connection between the input and the selected output fiber would be made via a microscopic ball lens. Switching of the optical connection from one output fiber to another would be effected by using a pair of thin-film shape-memory-alloy (SMA) actuators to toggle the lens between two resting switch positions. There are many optical switches some made of macroscopic parts by conventional fabrication techniques and some that are microfabricated and, hence, belong to the class of microelectromechanical systems (MEMS). Conventionally fabricated optical switches tend to be expensive. MEMS switches can be mass-produced at relatively low cost, but their attractiveness has been diminished by the fact that, heretofore, MEMS switches have usually been found to exhibit high insertion losses. The present switch is intended to serve as a prototype of low-loss MEMS switches. In addition, this is the first reported SMA-based optical switch. The optical fibers would be held in V grooves in a silicon frame. The lens would have a diameter of 1 m; it would be held by, and positioned between, the SMA actuators, which would be made of thin films of TiNi alloy. Although the SMA actuators are depicted here as having simple shapes for the sake of clarity of illustration, the real actuators would have complex, partly net-like shapes. With the exception of the lens and the optical fibers, the SMA actuators and other components of the switch would be made by microfabrication techniques. The components would be assembled into a sandwich structure to complete the fabrication of the switch. To effect switching, an electric current would be passed through one of the SMA actuators to heat it above its transition temperature, thereby causing it to deform to a different "remembered" shape. The two SMA actuators would be stiff enough that once switching had taken place and the electrical current was turned off, the lens would remain latched in the most recently selected position. In a test, the partially developed switch exhibited an insertion loss of only -1.9 dB and a switching contrast of 70 dB. One the basis of prior research on SMA actuators and assuming a lens displacement of 125 m between extreme positions, it has been estimated that the fully developed switch would be capable of operating at a frequency as high as 10 Hz.

Hollow fiber-optic Raman probes for small experimental animals

NASA Astrophysics Data System (ADS)

Katagiri, Takashi; Hattori, Yusuke; Suzuki, Toshiaki; Matsuura, Yuji; Sato, Hidetoshi

2007-02-01

Two types of hollow fiber-optic probes are developed to measure the in vivo Raman spectra of small animals. One is the minimized probe which is end-sealed with the micro-ball lens. The measured spectra reflect the information of the sample's sub-surface. This probe is used for the measurement of the esophagus and the stomach via an endoscope. The other probe is a confocal Raman probe which consists of a single fiber and a lens system. It is integrated into the handheld microscope. A simple and small multimodal probe is realized because the hollow optical fiber requires no optical filters. The performance of each probe is examined and the effectiveness of these probes for in vivo Raman spectroscopy is shown by animal tests.

Characteristics of the annular beam using a single axicon and a pair of lens

NASA Astrophysics Data System (ADS)

Ji, Ke; Lei, Ming; Yao, Baoli; Yan, Shaohui; Yang, Yanlong; Li, Ze; Dan, Dan; Menke, Neimule

2012-10-01

In optical trapping, annular beam as a kind of hollow beam is used to increase the axial trapping efficiency as well as the trapping stability. In this paper, a method for producing an annular beam by a system consisting of a single axicon and a pair of lens is proposed. The generated beam was also used as the optical tweezers. We use the geometrical optics to describe the propagation of light in the system. The calculated intensity distribution in three-dimensional space after the system shows a good agreement with the experimental results. The advantages of this method are simplicity of operation, good stability, and high transmittance, having possible applications in fields like optical microscopic, optical manipulation and electronic acceleration, etc.

Needle endomicroscope with a plastic, achromatic objective to perform optical biopsies of breast tissue

NASA Astrophysics Data System (ADS)

Kyrish, Matthew; Dobbs, Jessica; Richards-Kortum, Rebecca; Tkaczyk, Tomasz

2013-03-01

In order to diagnose cancer in breast tissue, a sample must be removed, prepared, and examined under a microscope. To provide an alternative to conventional biopsies, an endomicroscope intended to perform optical biopsies is demonstrated. The system provides high resolution, high contrast images in real-time which could allow a diagnosis to be made during surgery without the need for tissue removal. Optical sectioning is achieved via structured illumination to reject out of focus light. An image is relayed between the sample plane and the imaging system by a coherent fiber bundle with an achromatized objective lens at the distal tip of the fiber bundle which is the diameter of a biopsy needle. The custom, plastic objective provides correction for both the excitation and emission wavelengths of proflavine (452 nm and 515 nm, respectively). It also magnifies the object onto the distal tip of the fiber bundle to increase lateral resolution. The lenses are composed of the optical plastics Zeonex E48R, PMMA, and polystyrene. The lenses are fabricated via single point diamond turning and assembled using a zero alignment technique. The lateral resolution and chromatic focal shift were measured and in vitro images of breast carcinoma cells stained with proflavine were captured. The optical biopsy system is able to achieve optical sectioning and to resolve smaller features than the current high resolution microendoscope.

Contact lens-induced circumlimbal staining in silicone hydrogel contact lenses worn on a daily wear basis.

PubMed

Maïssa, Cécile; Guillon, Michel; Garofalo, Renee J

2012-01-01

The principal objective of the study was to measure the conjunctival staining produced in the circumlimbal region by silicone hydrogel contact lenses with different edge designs. The secondary objective was to investigate the association between circumlimbal staining and comfort. Four silicone hydrogel contact lenses: ACUVUE OASYS (knife edge design), AIR OPTIX, Biofinity (chisel edge rounded edge combination), and PureVision (rounded edge design), and 1 hydrogel contact lens, ACUVUE 2 (knife edge design), were tested. The study was conducted on a cohort population of 27 established soft contact lens wearers, who wore each contact lens type, in a random order, for a period of 10 (±2) days. Circumlimbal staining was measured in a double-masked fashion through image analysis of digital photographs of lissamine green taken under controlled experimental conditions. The results obtained showed that contact lens edge design was the primary factor controlling circumlimbal staining for silicone hydrogel lenses: a rounded edge away from the ocular surface produced the lowest staining (average, 0.19%) and a knife edge in close apposition to the ocular surface produced the highest staining (average, 1.34%). Contact lens material rigidity was also identified to affect circumlimbal staining and an inverse association between circumlimbal staining and contact lens comfort was demonstrated: the rounded edge design produced the lowest comfort (72 of 100) and the knife edge design produced the highest (87 out of 100). Soft contact lens wear induces circumlimbal staining, the level of staining being influenced by the contact lens edge design. However, high level of circumlimbal staining is not associated with decreased comfort.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, James H. H.; Suyu, Sherry H.; Chiueh, Tzihong

Strong gravitationally lensed quasars provide powerful means to study galaxy evolution and cosmology. Current and upcoming imaging surveys will contain thousands of new lensed quasars, augmenting the existing sample by at least two orders of magnitude. To find such lens systems, we built a robot, Chitah, that hunts for lensed quasars by modeling the configuration of the multiple quasar images. Specifically, given an image of an object that might be a lensed quasar, Chitah first disentangles the light from the supposed lens galaxy and the light from the multiple quasar images based on color information. A simple rule is designed to categorize the given object as a potential four-image (quad) or two-image (double) lensed quasar system. The configuration of the identified quasar images is subsequently modeled to classify whether the object is a lensed quasar system. We test the performance of Chitah using simulated lens systems based on the Canada–France–Hawaii Telescope Legacy Survey. For bright quads with large image separations (with Einstein radiusmore » $${r}_{\\mathrm{ein}}\\gt 1\\buildrel{\\prime\\prime}\\over{.} 1$$) simulated using Gaussian point-spread functions, a high true-positive rate (TPR) of $$\\sim 90\\%$$ and a low false-positive rate of $$\\sim 3\\%$$ show that this is a promising approach to search for new lens systems. We obtain high TPR for lens systems with $${r}_{\\mathrm{ein}}\\gtrsim 0\\buildrel{\\prime\\prime}\\over{.} 5$$, so the performance of Chitah is set by the seeing. We further feed a known gravitational lens system, COSMOS 5921+0638, to Chitah, and demonstrate that Chitah is able to classify this real gravitational lens system successfully. Our newly built Chitah is omnivorous and can hunt in any ground-based imaging surveys.« less

Focusing elliptical laser beams

NASA Astrophysics Data System (ADS)

Marchant, A. B.

1984-03-01

The spot formed by focusing an elliptical laser beam through an ordinary objective lens can be optimized by properly filling the objective lens. Criteria are given for maximizing the central irradiance and the line-spread function. An optimized spot is much less elliptical than the incident laser beam. For beam ellipticities as high as 2:1, this spatial filtering reduces the central irradiance by less than 14 percent.

Smartphone adapters for digital photomicrography.

PubMed

Roy, Somak; Pantanowitz, Liron; Amin, Milon; Seethala, Raja R; Ishtiaque, Ahmed; Yousem, Samuel A; Parwani, Anil V; Cucoranu, Ioan; Hartman, Douglas J

2014-01-01

Photomicrographs in Anatomic Pathology provide a means of quickly sharing information from a glass slide for consultation, education, documentation and publication. While static image acquisition historically involved the use of a permanently mounted camera unit on a microscope, such cameras may be expensive, need to be connected to a computer, and often require proprietary software to acquire and process images. Another novel approach for capturing digital microscopic images is to use smartphones coupled with the eyepiece of a microscope. Recently, several smartphone adapters have emerged that allow users to attach mobile phones to the microscope. The aim of this study was to test the utility of these various smartphone adapters. We surveyed the market for adapters to attach smartphones to the ocular lens of a conventional light microscope. Three adapters (Magnifi, Skylight and Snapzoom) were tested. We assessed the designs of these adapters and their effectiveness at acquiring static microscopic digital images. All adapters facilitated the acquisition of digital microscopic images with a smartphone. The optimal adapter was dependent on the type of phone used. The Magnifi adapters for iPhone were incompatible when using a protective case. The Snapzoom adapter was easiest to use with iPhones and other smartphones even with protective cases. Smartphone adapters are inexpensive and easy to use for acquiring digital microscopic images. However, they require some adjustment by the user in order to optimize focus and obtain good quality images. Smartphone microscope adapters provide an economically feasible method of acquiring and sharing digital pathology photomicrographs.

Evaluation of a recently developed noncontact specular microscope in comparison with conventional pachymetry devices.

PubMed

Módis, László; Szalai, Eszter; Németh, Gábor; Berta, András

2010-01-01

The study was conducted to assess the central corneal thickness (CCT) of the healthy cornea with a recently developed noncontact specular microscope (EM-3000; Tomey) and compare the results with those measured with a contact specular microscope and an ultrasound pachymeter. Agreement between measurements taken by 2 investigators was also studied. The right eyes of 41 healthy individuals who had negative history of contact lens wear, ophthalmic disease, or ocular surgery were examined. The CCT was determined sequentially with a noncontact specular microscope, a contact specular microscope (EM-1000; Tomey), and an ultrasound pachymeter (AL-2000; Tomey). Each evaluation with the specular microscopes was performed by 2 independent operators. A significant difference was detected in pachymetry measurements among the 3 instruments (p=0.01; analysis of variance). The mean CCT values were lower measured with the ultrasound pachymeter (537+/-30 microm) than the contact endothelial microscope (543+/-37 microm, p=0.17, Student t-test) and the noncontact microscope (549+/-33 microm, p<0.0001) (operator 1). There was no statistically significant difference in CCT measurements between the 2 endothelial microscopes (p=0.19). We found significant correlations (p<0.0001) in thickness measurements between each pair of instruments (r=0.91, noncontact microscopy and ultrasound pachymetry; r=0.74, noncontact and contact microscopy; r=0.72, contact microscopy and ultrasound pachymetry; Spearman rank correlation). The strong correlations among the 3 pachymetry devices suggest that the tested instruments provide reliable measurements; however, they cannot be used interchangeably.

Vibrationally resonant sum-frequency generation microscopy with a solid immersion lens

PubMed Central

Lee, Eun Seong; Lee, Sang-Won; Hsu, Julie; Potma, Eric O.

2014-01-01

We use a hemispheric sapphire lens in combination with an off-axis parabolic mirror to demonstrate high-resolution vibrationally resonant sum-frequency generation (VR-SFG) microscopy in the mid-infrared range. With the sapphire lens as an immersed solid medium, the numerical aperture (NA) of the parabolic mirror objective is enhanced by a factor of 1.72, from 0.42 to 0.72, close to the theoretical value of 1.76 ( = nsapphire). The measured lateral resolution is as high as 0.64 μm. We show the practical utility of the sapphire immersion lens by imaging collagen-rich tissues with and without the solid immersion lens. PMID:25071953

Chromatin remodeling enzyme Brg1 is required for mouse lens fiber cell terminal differentiation and its denucleation

PubMed Central

2010-01-01

Background Brahma-related gene 1 (Brg1, also known as Smarca4 and Snf2β) encodes an adenosine-5'-triphosphate (ATP)-dependent catalytical subunit of the (switch/sucrose nonfermentable) (SWI/SNF) chromatin remodeling complexes. SWI/SNF complexes are recruited to chromatin through multiple mechanisms, including specific DNA-binding factors (for example, heat shock transcription factor 4 (Hsf4) and paired box gene 6 (Pax6)), chromatin structural proteins (for example, high-mobility group A1 (HMGA1)) and/or acetylated core histones. Previous studies have shown that a single amino acid substitution (K798R) in the Brg1 ATPase domain acts via a dominant-negative (dn) mechanism. Genetic studies have demonstrated that Brg1 is an essential gene for early (that is, prior implantation) mouse embryonic development. Brg1 also controls neural stem cell maintenance, terminal differentiation of multiple cell lineages and organs including the T-cells, glial cells and limbs. Results To examine the roles of Brg1 in mouse lens development, a dnBrg1 transgenic construct was expressed using the lens-specific αA-crystallin promoter in postmitotic lens fiber cells. Morphological studies revealed abnormal lens fiber cell differentiation in transgenic lenses resulting in cataract. Electron microscopic studies showed abnormal lens suture formation and incomplete karyolysis (that is, denucleation) of lens fiber cells. To identify genes regulated by Brg1, RNA expression profiling was performed in embryonic day 15.5 (E15.5) wild-type and dnBrg1 transgenic lenses. In addition, comparisons between differentially expressed genes in dnBrg1 transgenic, Pax6 heterozygous and Hsf4 homozygous lenses identified multiple genes coregulated by Brg1, Hsf4 and Pax6. DNase IIβ, a key enzyme required for lens fiber cell denucleation, was found to be downregulated in each of the Pax6, Brg1 and Hsf4 model systems. Lens-specific deletion of Brg1 using conditional gene targeting demonstrated that Brg1 was required for lens fiber cell differentiation, for expression of DNase IIβ, for lens fiber cell denucleation and indirectly for retinal development. Conclusions These studies demonstrate a cell-autonomous role for Brg1 in lens fiber cell terminal differentiation and identified DNase IIβ as a potential direct target of SWI/SNF complexes. Brg1 is directly or indirectly involved in processes that degrade lens fiber cell chromatin. The presence of nuclei and other organelles generates scattered light incompatible with the optical requirements for the lens. PMID:21118511

Long working distance objective lenses for single atom trapping and imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pritchard, J. D., E-mail: jonathan.pritchard@strath.ac.uk; Department of Physics, University of Strathclyde, 107 Rottenrow East, Glasgow G4 0NG; Isaacs, J. A.

We present a pair of optimized objective lenses with long working distances of 117 mm and 65 mm, respectively, that offer diffraction limited performance for both Cs and Rb wavelengths when imaging through standard vacuum windows. The designs utilise standard catalog lens elements to provide a simple and cost-effective solution. Objective 1 provides NA = 0.175 offering 3 μm resolution whilst objective 2 is optimized for high collection efficiency with NA = 0.29 and 1.8 μm resolution. This flexible design can be further extended for use at shorter wavelengths by simply re-optimising the lens separations.

Still going strong: Leeuwenhoek at eighty.

PubMed

Anderson, Douglas

2014-07-01

At age 80, Antony van Leeuwenhoek was a world-famous scientist who came from a prosperous Delft family with a heritage of public service. He continued that tradition by serving in paid municipal offices. Self-taught, he began his scientific career in his 40s, when he began making hundreds of tiny single-lens microscopes. Pioneering the use of now-common microscopic techniques, he was the first human to see microbes and microscopic structures in animals, plants, and minerals. Over 50 years, he wrote only letters, more than 300 of them, and published half of them himself. More than a hundred were published in translation in the Royal Society's Philosophical Transactions. Today, Leeuwenhoek is considered in the lesser rank of scientists and is not well known outside of his homeland. Recent archival research in Delft has contributed new information about his life that helps to contextualize his science, but much remains to be learned.

Ultra-compact fiber-optic two-photon microscope for functional fluorescence imaging in vivo.

PubMed

Engelbrecht, Christoph J; Johnston, Richard S; Seibel, Eric J; Helmchen, Fritjof

2008-04-14

We present a small, lightweight two-photon fiberscope and demonstrate its suitability for functional imaging in the intact brain. Our device consists of a hollow-core photonic crystal fiber for efficient delivery of near-IR femtosecond laser pulses, a spiral fiber-scanner for resonant beam steering, and a gradient-index lens system for fluorescence excitation, dichroic beam splitting, and signal collection. Fluorescence light is remotely detected using a standard photomultiplier tube. All optical components have 1 mm dimensions and the microscope's headpiece weighs only 0.6 grams. The instrument achieves micrometer resolution at frame rates of typically 25 Hz with a field-of-view of up to 200 microns. We demonstrate functional imaging of calcium signals in Purkinje cell dendrites in the cerebellum of anesthetized rats. The microscope will be easily portable by a rat or mouse and thus should enable functional imaging in freely behaving animals.

High-resolution resonant and nonresonant fiber-scanning confocal microscope.

PubMed

Hendriks, Benno H W; Bierhoff, Walter C J; Horikx, Jeroen J L; Desjardins, Adrien E; Hezemans, Cees A; 't Hooft, Gert W; Lucassen, Gerald W; Mihajlovic, Nenad

2011-02-01

We present a novel, hand-held microscope probe for acquiring confocal images of biological tissue. This probe generates images by scanning a fiber-lens combination with a miniature electromagnetic actuator, which allows it to be operated in resonant and nonresonant scanning modes. In the resonant scanning mode, a circular field of view with a diameter of 190 μm and an angular frequency of 127 Hz can be achieved. In the nonresonant scanning mode, a maximum field of view with a width of 69 μm can be achieved. The measured transverse and axial resolutions are 0.60 and 7.4 μm, respectively. Images of biological tissue acquired in the resonant mode are presented, which demonstrate its potential for real-time tissue differentiation. With an outer diameter of 3 mm, the microscope probe could be utilized to visualize cellular microstructures in vivo across a broad range of minimally-invasive procedures.

Shack-Hartmann reflective micro profilometer

NASA Astrophysics Data System (ADS)

Gong, Hai; Soloviev, Oleg; Verhaegen, Michel; Vdovin, Gleb

2018-01-01

We present a quantitative phase imaging microscope based on a Shack-Hartmann sensor, that directly reconstructs the optical path difference (OPD) in reflective mode. Comparing with the holographic or interferometric methods, the SH technique needs no reference beam in the setup, which simplifies the system. With a preregistered reference, the OPD image can be reconstructed from a single shot. Also, the method has a rather relaxed requirement on the illumination coherence, thus a cheap light source such as a LED is feasible in the setup. In our previous research, we have successfully verified that a conventional transmissive microscope can be transformed into an optical path difference microscope by using a Shack-Hartmann wavefront sensor under incoherent illumination. The key condition is that the numerical aperture of illumination should be smaller than the numerical aperture of imaging lens. This approach is also applicable to characterization of reflective and slightly scattering surfaces.

The mammalian iris-ciliary complex affects organization and synthesis of cytoskeletal proteins of organ and tissue cultured lens epithelial cells.

PubMed

Banerjee, A; Emanuel, K; Parafina, J; Bagchi, M

1992-10-01

A water soluble growth inhibitor was isolated from the mammalian ocular iris-ciliary complex. The molecular weight of this protein is 10 kD or lower as determined by ultrafiltration fractionation. The iris-ciliary (IC) complex water soluble protein(s) significantly inhibits synthesis of lower molecular weight proteins of the epithelial cells of the organ cultured mammalian ocular lens. It was also found that this inhibitory effect of IC is mediated via the structural organization of the lens. Monolayer cultures of the lens epithelial cells exposed to IC did not manifest any inhibition of their protein synthesis. Moreover, these tissue cultured lens epithelial (TCLE) cells showed a significant increase in their protein synthetic activities in response to the presence of IC factors in the culture medium. It is postulated that the IC activity is modulated via either the lens capsule, an extracellular matrix, or due to the specific organization of the intact lens. The specific effects of IC on the cytoskeletal organization and synthesis in the organ cultured lens epithelial (OCLE) and TCLE cells were also examined. Both groups, treated with IC factors, manifested significant alterations in their protein synthetic activities and cytoskeletal architecture. The 3H-leucine incorporation experiments showed that alpha-actin and alpha-tubulin synthesis is partially inhibited by IC factors in OCLE cells but vimentin synthesis is not, whereas in TCLE cells all of them showed increased synthesis in response to IC factors. Turnover rates of these proteins in both OCLE and TCLE cells were also computed. The immunofluorescence and microscopic evaluation of OCLE and TCLE cells exposed to IC factors illustrated significant alteration in the cytoarchitecture of the filaments. We demonstrate that an inhibitor(s) molecule of 10 kD or lower size isolated from IC inhibited protein synthesis of OCLE cells and stimulated protein synthesis in TCLE cells. The IC factor also affects the synthesis and organization of cytoskeletal filaments of both the OCLE and TCLE cells.

Kink-bands: Shock deformation of biotite resulting from a nuclear explosion

USGS Publications Warehouse

Cummings, D.

1965-01-01

Microscopic examination of granodiorite samples from the shock region around a nuclear explosion reveals sharply folded lens-shaped zones (kink-bands) in the mineral biotite. Fifty percent of these zones are oriented approximately 90?? to the direction of shock-wave propagation, but other zones are symmetrically concentrated at shear angles of 50?? and 70?? to the direction of shock-wave propagation.

Metaphor and Pedagogy in Early Buddhist Literature: An Edition and Study of Two Sutras from the Senior Collection of Gandhari Manuscripts

ERIC Educational Resources Information Center

Marino, Joseph

2017-01-01

This dissertation examines the role of metaphorical language in early Buddhist literature through the lens of two previously unpublished Gandhari sutras on a manuscript from the Robert Senior Collection. At the microscopic level, I offer an edition, translation, and textual analysis of a Buddhist manuscript containing two Sa?yuktagama-type sutras…

A Low Temperature Scanning Force Microscope with a Vertical Cantilever and Interferometric Detection Scheme

NASA Astrophysics Data System (ADS)

Kim, Jeehoon; Williams, T. L.; Chu, Sang Lin; Korre, Hasan; Chalfin, Max; Hoffman, J. E.

2008-03-01

We have developed a fiber-optic interferometry system with a vertical cantilever for scanning force microscopy. A lens, mounted on a Pan-type walker, was used to collect the interference signal in the cavity between the cantilever and the single mode fiber. This vertical geometry has several advantages: (1) it is directly sensitive to lateral forces; (2) low spring constant vertical cantilevers may allow increased force sensitivity by solving the ``snap-in'' problem that occurs with soft horizontal cantilevers. We have sharpened vertical cantilevers by focused ion beam (FIB), achieving a tip radius of 20 nm. We will show test results of a magnetic force microscope (MFM) with this vertical cantilever system.

Enhancement of graphene visibility on transparent substrates by refractive index optimization.

PubMed

Gonçalves, Hugo; Alves, Luís; Moura, Cacilda; Belsley, Michael; Stauber, Tobias; Schellenberg, Peter

2013-05-20

Optical reflection microscopy is one of the main imaging tools to visualize graphene microstructures. Here is reported a novel method that employs refractive index optimization in an optical reflection microscope, which greatly improves the visibility of graphene flakes. To this end, an immersion liquid with a refractive index that is close to that of the glass support is used in-between the microscope lens and the support improving the contrast and resolution of the sample image. Results show that the contrast of single and few layer graphene crystals and structures can be enhanced by a factor of 4 compared to values commonly achieved with transparent substrates using optical reflection microscopy lacking refractive index optimization.

Technical considerations for designing low-cost, long-wave infrared objectives

NASA Astrophysics Data System (ADS)

Desroches, Gerard; Dalzell, Kristy; Robitaille, Blaise

2014-06-01

With the growth of uncooled infrared imaging in the consumer market, the balance between cost implications and performance criteria in the objective lens must be examined carefully. The increased availability of consumer-grade, long-wave infrared cameras is related to a decrease in military usage but it is also due to the decreasing costs of the cameras themselves. This has also driven up demand for low-cost, long-wave objectives that can resolve smaller pixels while maintaining high performance. Smaller pixels are traditionally associated with high cost objectives because of higher resolution requirements but, with careful consideration of all the requirements and proper selection of materials, costs can be moderated. This paper examines the cost/performance trade-off implications associated with optical and mechanical requirements of long-wave infrared objectives. Optical performance, f-number, field of view, distortion, focus range and thermal range all affect the cost of the objective. Because raw lens material cost is often the most expensive item in the construction, selection of the material as well as the shape of the lens while maintaining acceptable performance and cost targets were explored. As a result of these considerations, a low-cost, lightweight, well-performing objective was successfully designed, manufactured and tested.

A gravitational lens candidate with an unusually red optical counterpart

NASA Technical Reports Server (NTRS)

Hewitt, J. N.; Turner, E. L.; Lawrence, C. R.; Schneider, D. P.; Brody, J. P.

1992-01-01

The properties of the strong radio source MG0414 + 0534 are described. It is found to display many of the properties expected in a gravitational lens system. At radio wavelengths and 0.5-arcsec resolution, MG0414 + 0534 is made up of four compact components whose unusual configuration and relative flux densities are similar to those found in confirmed four-image gravitational lens systems. At optical wavelengths three objects are detected, consistent with there being optical objects at the positions of the radio components, given the lower optical resolution. The radio and optical centroid positions agree within the astrometric errors, and the relative ordering of the fluxes is the same. The colors and radiooptical spectral indices are similar, but there are differences larger than the photometric errors and the measured variability (about 30 percent). Extinction by dust might simultaneously explain the unusually red color and the absence of light from a lens.

Improvement of spectral and axial resolutions in modified coded aperture correlation holography (COACH) imaging system

NASA Astrophysics Data System (ADS)

Vijayakumar, A.; Rosen, Joseph

2017-05-01

Coded aperture correlation holography (COACH) is a recently developed incoherent digital holographic technique. In COACH, two holograms are recorded: the object hologram for the object under study and another hologram for a point object called PSF hologram. The holograms are recorded by interfering two beams, both diffracted from the same object point, but only one of them passes through a random-like coded phase mask (CPM). The same CPM is used for recording the object as well as the PSF holograms. The image is reconstructed by correlating the object hologram with a processed version of the PSF hologram. The COACH holographic technique exhibits the same transverse and axial resolution of the regular imaging, but with the unique capability of storing 3D information. The basic COACH configuration consists of a single spatial light modulator (SLM) used for displaying the CPM. In this study, the basic COACH configuration has been advanced by employing two spatial light modulators (SLMs) in the setup. The refractive lens used in the basic COACH setup for collecting and collimating the light diffracted by the object is replaced by an SLM on which an equivalent diffractive lens is displayed. Unlike a refractive lens, the diffractive lens displayed on the first SLM focuses light with different wavelengths to different axial planes, which are separated by distances larger than the axial correlation lengths of the CPM for any visible wavelength. This characteristic extends the boundaries of COACH from three-dimensional to four-dimensional imaging with the wavelength as its fourth dimension.

HST image of Gravitational Lens G2237 + 305 or 'Einstein Cross'

NASA Technical Reports Server (NTRS)

1990-01-01

European Space Agency (ESA) Faint Object Camera (FOC) science image was taken from the Hubble Space Telescope (HST) of Gravitational Lens G2237 + 305 or 'Einstein Cross'. The gravitational lens G2237 + 305 or 'Einstein Cross' shows four images of a very distant quasar which has been multiple-imaged by a relatively nearby galaxy acting as a gravitational lens. The angular separation between the upper and lower images is 1.6 arc seconds. Photo was released from Goddard Space Flight Center (GSFC) 09-12-90.

Concept and design of charged particle optics using energy Fourier plane collimation

NASA Astrophysics Data System (ADS)

Yang, Guojun; Wei, Tao; Zhang, Zhuo; He, Xiaozhong; Zhang, Xiaoding; Li, Yiding; Shi, Jinshui

2014-09-01

Charged particle radiography has become a promising new approach in the field of transmission radiography because of the invention of the magnetic imaging lens. The using of the imaging lens makes it possible for thick objects to get significantly improved transmission radiography. Currently, the conventional charged particle radiography only uses the information of the flux attenuation and the angular scattering of the transmitted particles to determine the properties of the sample. However, the energy loss of the incident particles introduced by ionizations throughout the object limits the spatial resolution of the image because of the chromatic blur. In this paper a new concept of imaging lens that uses the information of the energy loss is proposed. With a specially designed imaging lens, the information of the energy loss could result in apparent contrast in the final image. This design procedure of the energy loss imaging lens is presented, and a preliminary design is verified by numerical simulations. Experimental demonstration is also expected on a cyclotron at the Institute of Fluid Physics, CAEP.

Comparative evaluation of management of gingival recession using subepithelial connective tissue graft and collagen membrane by periodontal microsurgical technique: A clinical study of 40 cases

PubMed Central

Thankkappan, Prasanth; Roy, Subrata; Mandlik, Vivek Bapurao

2016-01-01

Background: New technologies, instruments, and surgical techniques are necessary to help the clinician ensure the best result and satisfy the patient's expectations, and surgical microscope has been thoroughly demonstrated as a useful tool. A clinical study was carried out to compare 2 different types of root coverage procedures using periodontal microsurgical procedure. Materials and Methods: Forty patients were selected and divided into Group A and Group B. Group A subjects were treated with subepithelial connective tissue graft (CTG) whereas Group B subjects were treated using a resorbable collagen membrane. The procedures were performed with the help of an operating microscope using 250 mm objective lens and ×6 magnification. Results: A comparison between baseline, 1, 3, and 12 months have been done between groups among all parameters. It has been noticed that the root coverage was better in Group A subjects at all time. At 12 months, Group A showed 81.42% coverage where in Group B it was 70.08%. Similarly, increase in the width of keratinized gingiva and attached gingiva were more in Group A. Conclusions: The present study showed that use of microsurgical instrument helped to deliver precise incision, better visual acuity, and improved illumination which facilitate to gain a better final outcome. Root coverage was better in the patients using CTG. PMID:27143833

Reflectance confocal microscope for imaging oral tissues in vivo, potentially with line scanning as a low-cost approach for clinical use

NASA Astrophysics Data System (ADS)

Peterson, Gary; Abeytunge, Sanjeewa; Eastman, Zachary; Rajadhyaksha, Milind

2012-02-01

Reflectance confocal microscopy with a line scanning approach potentially offers a smaller, simpler and less expensive approach than traditional methods of point scanning for imaging in living tissues. With one moving mechanical element (galvanometric scanner), a linear array detector and off-the-shelf optics, we designed a compact (102x102x76mm) line scanning confocal reflectance microscope (LSCRM) for imaging human tissues in vivo in a clinical setting. Custom-designed electronics, based on field programmable gate array (FPGA) logic has been developed. With 405 nm illumination and a custom objective lens of numerical aperture 0.5, lateral resolution was measured to be 0.8 um (calculated 0.64 um). The calculated optical sectioning is 3.2 um. Preliminary imaging shows nuclear and cellular detail in human skin and oral epithelium in vivo. Blood flow is also visualized in the deeper connective tissue (lamina propria) in oral mucosa. Since a line is confocal only in one dimension (parallel) but not in the other, the detection is more sensitive to multiply scattered out of focus background noise than in the traditional point scanning configuration. Based on the results of our translational studies thus far, a simpler, smaller and lower-cost approach based on a LSCRM appears to be promising for clinical imaging.

A portable optical reader and wall projector towards enumeration of bio-conjugated beads or cells

PubMed Central

McArdle, Niamh A.; Kendlin, Jane L.; O’Connell, Triona M.; Ducrée, Jens

2017-01-01

Measurement of the height of a packed column of cells or beads, which can be direclty related to the number of cells or beads present in a chamber, is an important step in a number of diagnostic assays. For example, haematocrit measurements may rapidly identify anemia or polycthemia. Recently, user-friendly and cost-efficient Lab-on-a-Chip devices have been developed towards isolating and counting cell sub-populations for diagnostic purposes. In this work, we present a low-cost optical module for estimating the filling level of packed magnetic beads within a Lab-on-a-Chip device. The module is compatible with a previously introduced, disposable microfluidic chip for rapid determination of CD4+ cell counts. The device is a simple optical microscope module is manufactured by 3D printing. An objective lens directly interrogates the height of packed beads which are efficiently isolated on the finger-actuated chip. Optionally, an inexpensive, battery-powered Light Emitting Diode may project a shadow of the microfluidic chip at approximately 50-fold magnification onto a nearby surface. The reader is calibrated with the filling levels of known concentrations of paramagnetic beads within the finger actuated chip. Results in direct and projector mode are compared to measurements from a conventional, inverted white-light microscope. All three read-out methods indicate a maximum variation of 6.5% between methods. PMID:29267367

Structural Characterization and Gas Reactions of Small Metal Particles by High Resolution In-situ TEM and TED. [Transmission Electron Microscopy and Transmission Electron Diffraction

NASA Technical Reports Server (NTRS)

Heinemann, K.

1985-01-01

A commercial electron microscope with flat-plate upper pole piece configuration of the objective lens and top entry specimen introduction was modified to obtain 5 x 10 to the minus 10th power mbar pressure at the site of the specimen while maintaining the convenience of a specimen airlock system that allows operation in the 10 to the 10th power mbar range within 15 minutes after specimen change. The specimen chamber contains three wire evaporation sources, a specimen heater, and facilities for oxygen or hydrogen plasma treatment to clean as-introduced specimens. Evacuation is achieved by dural differential pumping, with fine entrance and exit apertures for the electron beam. With the microscope operating at .000001 mbar, the first differential pumping stage features a high-speed cryopump operating in a stainless steel chamber that can be mildly baked and reaches 1 x 10 to the minus 8th power mbar. The second stage, containing the evaporation sources and a custom ionization gauge within 10 cm from the specimen, is a rigorously uncompromised all-metal uhv-system that is bakable to above 200 C throughout and is pumped with an 80-liter ion pump. Design operating pressures and image quality (resolution of metal particles smaller than 1 nm in size) was achieved.

Mirror-based broadband scanner with minimized aberration

NASA Astrophysics Data System (ADS)

Yu, Jiun-Yann; Tzeng, Yu-Yi; Huang, Chen-Han; Chui, Hsiang-Chen; Chu, Shi-Wei

2009-02-01

To obtain specific biochemical information in optical scanning microscopy, labeling technique is routinely required. Instead of the complex and invasive sample preparation procedures, incorporating spectral acquisition, which commonly requires a broadband light source, provides another mechanism to enhance molecular contrast. But most current optical scanning system is lens-based and thus the spectral bandwidth is limited to several hundred nanometers due to anti-reflection coating and chromatic aberration. The spectral range of interest in biological research covers ultraviolet to infrared. For example, the absorption peak of water falls around 3 μm, while most proteins exhibit absorption in the UV-visible regime. For imaging purpose, the transmission window of skin and cerebral tissues fall around 1300 and 1800 nm, respectively. Therefore, to extend the spectral bandwidth of an optical scanning system from visible to mid-infrared, we propose a system composed of metallic coated mirrors. A common issue in such a mirror-based system is aberrations induced by oblique incidence. We propose to compensate astigmatism by exchanging the sagittal and tangential planes of the converging spherical mirrors in the scanning system. With the aid of an optical design software, we build a diffraction-limited broadband scanning system with wavefront flatness better than λ/4 at focal plane. Combined with a mirror-based objective this microscopic system will exhibit full spectral capability and will be useful in microscopic imaging and therapeutic applications.

Miniature self-contained vacuum compatible electronic imaging microscope

DOEpatents

Naulleau, Patrick P.; Batson, Phillip J.; Denham, Paul E.; Jones, Michael S.

2001-01-01

A vacuum compatible CCD-based microscopic camera with an integrated illuminator. The camera can provide video or still feed from the microscope contained within a vacuum chamber. Activation of an optional integral illuminator can provide light to illuminate the microscope subject. The microscope camera comprises a housing with a objective port, modified objective, beam-splitter, CCD camera, and LED illuminator.

Apparatus for direct-to-digital spatially-heterodyned holography

DOEpatents

Thomas, Clarence E.; Hanson, Gregory R.

2006-12-12

An apparatus operable to record a spatially low-frequency heterodyne hologram including spatially heterodyne fringes for Fourier analysis includes: a laser; a beamsplitter optically coupled to the laser; an object optically coupled to the beamsplitter; a focusing lens optically coupled to both the beamsplitter and the object; a digital recorder optically coupled to the focusing lens; and a computer that performs a Fourier transform, applies a digital filter, and performs an inverse Fourier transform. A reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form a spatially low-frequency heterodyne hologram including spatially heterodyne fringes for Fourier analysis which is recorded by the digital recorder, and the computer transforms the recorded spatially low-frequency heterodyne hologram including spatially heterodyne fringes and shifts axes in Fourier space to sit on top of a heterodyne carrier frequency defined by an angle between the reference beam and the object beam and cuts off signals around an original origin before performing the inverse Fourier transform.

The Master Lens Database and The Orphan Lenses Project

NASA Astrophysics Data System (ADS)

Moustakas, Leonidas

2012-10-01

Strong gravitational lenses are uniquely suited for the study of dark matter structure and substructure within massive halos of many scales, act as gravitational telescopes for distant faint objects, and can give powerful and competitive cosmological constraints. While hundreds of strong lenses are known to date, spanning five orders of magnitude in mass scale, thousands will be identified this decade. To fully exploit the power of these objects presently, and in the near future, we are creating the Master Lens Database. This is a clearinghouse of all known strong lens systems, with a sophisticated and modern database of uniformly measured and derived observational and lens-model derived quantities, using archival Hubble data across several instruments. This Database enables new science that can be done with a comprehensive sample of strong lenses. The operational goal of this proposal is to develop the process and the code to semi-automatically stage Hubble data of each system, create appropriate masks of the lensing objects and lensing features, and derive gravitational lens models, to provide a uniform and fairly comprehensive information set that is ingested into the Database. The scientific goal for this team is to use the properties of the ensemble of lenses to make a new study of the internal structure of lensing galaxies, and to identify new objects that show evidence of strong substructure lensing, for follow-up study. All data, scripts, masks, model setup files, and derived parameters, will be public, and free. The Database will be accessible online and through a sophisticated smartphone application, which will also be free.

Sodium toxicity and pathology associated with exposure of waterfowl to hypersaline playa lakes of southeast New Mexico

USGS Publications Warehouse

Meteyer, C.U.; Dubielzig, R.D.; Dein, F.J.; Baeten, L.A.; Moore, M.K.; Jehl, J.R.; Wesenberg, K.E.

1997-01-01

Cause of mortality was studied in waterfowl in hypersaline playa lakes of southeast New Mexico during spring and fall migration. Mortality was not common in wild ducks resting on the playas during good weather. However, when birds remained on the lakes for prolonged periods of time, such as during experimental trials and stormy weather, a heavy layer of salt precipitated on their feathers. Sodium toxicity was the cause of death for all experimental mallards housed on playa water and for 50% of the wild waterfowl found moribund or dead during the spring of 1995. Gross lesions included heavy salt precipitation on the feathers, ocular lens opacities, deeply congested brains, and dilated, thin-walled, fluid-filled cloacae. Microscopic lesions in the more severely affected birds included liquefaction of ocular lens cortex with lens fiber swelling and multifocal to diffuse ulcerative conjunctivitis with severe granulocytic inflammation, edema, and granulocytic vasculitis resulting in thrombosis. Inflammation similar to that seen in the conjunctiva occasionally involved the mucosa of the mouth, pharynx, nasal turbinates, cloaca, and bursa. Transcorneal movement of water in response to the hypersaline conditions on the playa lakes or direct contact with salt crystals could induce anterior segment dehydration of the aqueous humor and increased osmotic pressure on the lens, leading to cataract formation.

A mini-microscope for in situ monitoring of cells.

PubMed

Kim, Sang Bok; Koo, Kyo-in; Bae, Hojae; Dokmeci, Mehmet R; Hamilton, Geraldine A; Bahinski, Anthony; Kim, Sun Min; Ingber, Donald E; Khademhosseini, Ali

2012-10-21

A mini-microscope was developed for in situ monitoring of cells by modifying off-the-shelf components of a commercial webcam. The mini-microscope consists of a CMOS imaging module, a small plastic lens and a white LED illumination source. The CMOS imaging module was connected to a laptop computer through a USB port for image acquisition and analysis. Due to its compact size, 8 × 10 × 9 cm, the present microscope is portable and can easily fit inside a conventional incubator, and enables real-time monitoring of cellular behaviour. Moreover, the mini-microscope can be used for imaging cells in conventional cell culture flasks, such as Petri dishes and multi-well plates. To demonstrate the operation of the mini-microscope, we monitored the cellular migration of mouse 3T3 fibroblasts in a scratch assay in medium containing three different concentrations of fetal bovine serum (5, 10, and 20%) and demonstrated differential responses depending on serum levels. In addition, we seeded embryonic stem cells inside poly(ethylene glycol) microwells and monitored the formation of stem cell aggregates in real time using the mini-microscope. Furthermore, we also combined a lab-on-a-chip microfluidic device for microdroplet generation and analysis with the mini-microscope and observed the formation of droplets under different flow conditions. Given its cost effectiveness, robust imaging and portability, the presented platform may be useful for a range of applications for real-time cellular imaging using lab-on-a-chip devices at low cost.

A mini-microscope for in situ monitoring of cells†‡

PubMed Central

Kim, Sang Bok; Koo, Kyo-in; Bae, Hojae; Dokmeci, Mehmet R.; Hamilton, Geraldine A.; Bahinski, Anthony; Kim, Sun Min; Ingber, Donald E.

2013-01-01

A mini-microscope was developed for in situ monitoring of cells by modifying off-the-shelf components of a commercial webcam. The mini-microscope consists of a CMOS imaging module, a small plastic lens and a white LED illumination source. The CMOS imaging module was connected to a laptop computer through a USB port for image acquisition and analysis. Due to its compact size, 8 × 10 × 9 cm, the present microscope is portable and can easily fit inside a conventional incubator, and enables real-time monitoring of cellular behaviour. Moreover, the mini-microscope can be used for imaging cells in conventional cell culture flasks, such as Petri dishes and multi-well plates. To demonstrate the operation of the mini-microscope, we monitored the cellular migration of mouse 3T3 fibroblasts in a scratch assay in medium containing three different concentrations of fetal bovine serum (5, 10, and 20%) and demonstrated differential responses depending on serum levels. In addition, we seeded embryonic stem cells inside poly(ethylene glycol) microwells and monitored the formation of stem cell aggregates in real time using the mini-microscope. Furthermore, we also combined a lab-on-a-chip microfluidic device for microdroplet generation and analysis with the mini-microscope and observed the formation of droplets under different flow conditions. Given its cost effectiveness, robust imaging and portability, the presented platform may be useful for a range of applications for real-time cellular imaging using lab-on-a-chip devices at low cost. PMID:22911426

3D+time acquisitions of 3D cell culture by means of lens-free tomographic microscopy

NASA Astrophysics Data System (ADS)

Berdeu, Anthony; Laperrousaz, Bastien; Bordy, Thomas; Morales, S.; Gidrol, Xavier; Picollet-D'hahan, Nathalie; Allier, Cédric

2018-02-01

We propose a three-dimensional (3D) imaging platform based on lens-free microscopy to perform multi-angle acquisitions on 3D cell cultures embedded in extracellular matrix (ECM). We developed algorithms based on the Fourier diffraction theorem to perform fully 3D reconstructions of biological samples and we adapted the lens-free microscope to incubator conditions. Here we demonstrate for the first time, 3D+time lens-free acquisitions of 3D cell culture over 8 days directly into the incubator. The 3D reconstructed volume is as large as 5 mm3 and provides a unique way to observe in the same 3D cell culture experiment multiple cell migration strategies. Namely, in a 3D cell culture of prostate epithelial cells embedded within a Matrigel® matrix, we are able to distinguish single cell 'leaders', migration of cell clusters, migration of large aggregates of cells, and also close-gap and large-scale branching. In addition, we observe long-scale 3D deformations of the ECM that modify the geometry of the 3D cell culture. Interestingly, we also observed the opposite, i.e. we found that large aggregates of cells may deform the ECM by generating traction forces over very long distances. In sum we put forward a novel 3D lens-free microscopy tomographic technique to study the single and collective cell migrations, the cell-to-cell interactions and the cell-to-matrix interactions.

Handheld tunable focus confocal microscope utilizing a double-clad fiber coupler for in vivo imaging of oral epithelium

NASA Astrophysics Data System (ADS)

Olsovsky, Cory; Hinsdale, Taylor; Cuenca, Rodrigo; Cheng, Yi-Shing Lisa; Wright, John M.; Rees, Terry D.; Jo, Javier A.; Maitland, Kristen C.

2017-05-01

A reflectance confocal endomicroscope with double-clad fiber coupler and electrically tunable focus lens is applied to imaging of the oral mucosa. The instrument is designed to be lightweight and robust for clinical use. The tunable lens allows axial scanning through >250 μm in the epithelium when the probe tip is placed in contact with tissue. Images are acquired at 6.6 frames per second with a field of view diameter up to 850 μm. In vivo imaging of a wide range of normal sites in the oral cavity demonstrates the accessibility of the handheld probe. In vivo imaging of clinical lesions diagnosed as inflammation and dysplasia illustrates the ability of reflectance confocal endomicroscopy to image cellular changes associated with pathology.

Holographic zoom system based on spatial light modulator and liquid device

NASA Astrophysics Data System (ADS)

Wang, Di; Li, Lei; Liu, Su-Juan; Wang, Qiong-Hua

2018-02-01

In this paper, two holographic zoom systems are proposed based on the programmability of spatial light modulator (SLM) and zoom characteristics of liquid lens. An active optical zoom system is proposed in which the zoom module is composed of a liquid lens and an SLM. By controlling the focal lengths of the liquid lens and the encoded digital lens on the SLM, we can change the magnification of an image without mechanical moving parts and keep the output plane stationary. Then a color holographic zoom system based on a liquid lens is proposed. The system processes the color separation of the original object for red, green, and blue components and generated three holograms respectively. A new hologram with specific reconstructed distance can be generated by combing the hologram of the digital lens with the hologram of the image. By controlling the focal lengths of the liquid lens and the encoded digital lens on the SLM, we can change the magnification of the reconstructed image.

THREE-DIMENSIONAL RANDOM ACCESS MULTIPHOTON MICROSCOPY FOR FAST FUNCTIONAL IMAGING OF NEURONAL ACTIVITY

PubMed Central

Reddy, Gaddum Duemani; Kelleher, Keith; Fink, Rudy; Saggau, Peter

2009-01-01

The dynamic ability of neuronal dendrites to shape and integrate synaptic responses is the hallmark of information processing in the brain. Effectively studying this phenomenon requires concurrent measurements at multiple sites on live neurons. Significant progress has been made by optical imaging systems which combine confocal and multiphoton microscopy with inertia-free laser scanning. However, all systems developed to date restrict fast imaging to two dimensions. This severely limits the extent to which neurons can be studied, since they represent complex three-dimensional (3D) structures. Here we present a novel imaging system that utilizes a unique arrangement of acousto-optic deflectors to steer a focused ultra-fast laser beam to arbitrary locations in 3D space without moving the objective lens. As we demonstrate, this highly versatile random-access multiphoton microscope supports functional imaging of complex 3D cellular structures such as neuronal dendrites or neural populations at acquisition rates on the order of tens of kilohertz. PMID:18432198

The importance of the boundary condition in the transport of intensity equation based phase measurement

NASA Astrophysics Data System (ADS)

Zhang, Jialin; Chen, Qian; Li, Jiaji; Zuo, Chao

2017-02-01

The transport of intensity equation (TIE) is a powerful tool for direct quantitative phase retrieval in microscopy imaging. However, there may be some problems when dealing with the boundary condition of the TIE. The previous work introduces a hard-edged aperture to the camera port of the traditional bright field microscope to generate the boundary signal for the TIE solver. Under this Neumann boundary condition, we can obtain the quantitative phase without any assumption or prior knowledge about the test object and the setup. In this paper, we will demonstrate the effectiveness of this method based on some experiments in practice. The micro lens array will be used for the comparison of two TIE solvers results based on introducing the aperture or not and this accurate quantitative phase imaging technique allows measuring cell dry mass which is used in biology to follow cell cycle, to investigate cell metabolism, or to address effects of drugs.

The Project Of Another Low-Cost Metaphase Finder.

PubMed

Furukawa, Akira

2016-12-01

The most popular and 'gold standard' phenomenon in Biological dosimetry is the appearance of dicentric chromosomes in metaphase in white blood cells. The metaphase finder is a tool for biological dosimetry that finds metaphase cells on slide glasses. The author and a software company were using new special software that was faster than conventional systems. A Nikon Eclipse Ni-E microscope with motorised X-Y stage, 4× objective lens and 1920 × 1024 pixels colour camera for hardware were used. The software uses mathematical morphology filters. The new system was compact and low-priced. And the remarkable point is, this system can be applicable not only to human blood, but also to non-human samples. The speed was 208-236 s per 5 × 20 mm area, while capturing 378 images, which achieved the aim of the project. The false-positive ratio achieved below 5% in some slides. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Cell-phone-based platform for biomedical device development and education applications.

PubMed

Smith, Zachary J; Chu, Kaiqin; Espenson, Alyssa R; Rahimzadeh, Mehdi; Gryshuk, Amy; Molinaro, Marco; Dwyre, Denis M; Lane, Stephen; Matthews, Dennis; Wachsmann-Hogiu, Sebastian

2011-03-02

In this paper we report the development of two attachments to a commercial cell phone that transform the phone's integrated lens and image sensor into a 350x microscope and visible-light spectrometer. The microscope is capable of transmission and polarized microscopy modes and is shown to have 1.5 micron resolution and a usable field-of-view of 150 x 50 with no image processing, and approximately 350 x 350 when post-processing is applied. The spectrometer has a 300 nm bandwidth with a limiting spectral resolution of close to 5 nm. We show applications of the devices to medically relevant problems. In the case of the microscope, we image both stained and unstained blood-smears showing the ability to acquire images of similar quality to commercial microscope platforms, thus allowing diagnosis of clinical pathologies. With the spectrometer we demonstrate acquisition of a white-light transmission spectrum through diffuse tissue as well as the acquisition of a fluorescence spectrum. We also envision the devices to have immediate relevance in the educational field.

Cell-Phone-Based Platform for Biomedical Device Development and Education Applications

PubMed Central

Smith, Zachary J.; Chu, Kaiqin; Espenson, Alyssa R.; Rahimzadeh, Mehdi; Gryshuk, Amy; Molinaro, Marco; Dwyre, Denis M.; Lane, Stephen; Matthews, Dennis; Wachsmann-Hogiu, Sebastian

2011-01-01

In this paper we report the development of two attachments to a commercial cell phone that transform the phone's integrated lens and image sensor into a 350× microscope and visible-light spectrometer. The microscope is capable of transmission and polarized microscopy modes and is shown to have 1.5 micron resolution and a usable field-of-view of 150×150 with no image processing, and approximately 350×350 when post-processing is applied. The spectrometer has a 300 nm bandwidth with a limiting spectral resolution of close to 5 nm. We show applications of the devices to medically relevant problems. In the case of the microscope, we image both stained and unstained blood-smears showing the ability to acquire images of similar quality to commercial microscope platforms, thus allowing diagnosis of clinical pathologies. With the spectrometer we demonstrate acquisition of a white-light transmission spectrum through diffuse tissue as well as the acquisition of a fluorescence spectrum. We also envision the devices to have immediate relevance in the educational field. PMID:21399693

Thimble microscope system

NASA Astrophysics Data System (ADS)

Kamal, Tahseen; Rubinstein, Jaden; Watkins, Rachel; Cen, Zijian; Kong, Gary; Lee, W. M.

2016-12-01

Wearable computing devices, e.g. Google Glass, Smart watch, embodies the new human design frontier, where technology interfaces seamlessly with human gestures. During examination of any subject in the field (clinic, surgery, agriculture, field survey, water collection), our sensory peripherals (touch and vision) often go hand-in-hand. The sensitivity and maneuverability of the human fingers are guided with tight distribution of biological nerve cells, which perform fine motor manipulation over a range of complex surfaces that is often out of sight. Our sight (or naked vision), on the other hand, is generally restricted to line of sight that is ill-suited to view around corner. Hence, conventional imaging methods are often resort to complex light guide designs (periscope, endoscopes etc) to navigate over obstructed surfaces. Using modular design strategies, we constructed a prototype miniature microscope system that is incorporated onto a wearable fixture (thimble). This unique platform allows users to maneuver around a sample and take high resolution microscopic images. In this paper, we provide an exposition of methods to achieve a thimble microscopy; microscope lens fabrication, thimble design, integration of miniature camera and liquid crystal display.

Remote adjustable focus Raman spectroscopy probe

DOEpatents

Schmucker, John E.; Blasi, Raymond J.; Archer, William B.

1999-01-01

A remote adjustable focus Raman spectroscopy probe allows for analyzing Raman scattered light from a point of interest external probe. An environmental barrier including at least one window separates the probe from the point of interest. An optical tube is disposed adjacent to the environmental barrier and includes a long working length compound lens objective next to the window. A beam splitter and a mirror are at the other end. A mechanical means is used to translated the prove body in the X, Y, and Z directions resulting in a variable focus optical apparatus. Laser light is reflected by the beam splitter and directed toward the compound lens objective, then through the window and focused on the point of interest. Raman scattered light is then collected by the compound lens objective and directed through the beam splitter to a mirror. A device for analyzing the light, such as a monochrometer, is coupled to the mirror.

A Field-Portable Cell Analyzer without a Microscope and Reagents

PubMed Central

Oh, Sangwoo; Lee, Moonjin; Hwang, Yongha

2017-01-01

This paper demonstrates a commercial-level field-portable lens-free cell analyzer called the NaviCell (No-stain and Automated Versatile Innovative cell analyzer) capable of automatically analyzing cell count and viability without employing an optical microscope and reagents. Based on the lens-free shadow imaging technique, the NaviCell (162 × 135 × 138 mm3 and 1.02 kg) has the advantage of providing analysis results with improved standard deviation between measurement results, owing to its large field of view. Importantly, the cell counting and viability testing can be analyzed without the use of any reagent, thereby simplifying the measurement procedure and reducing potential errors during sample preparation. In this study, the performance of the NaviCell for cell counting and viability testing was demonstrated using 13 and six cell lines, respectively. Based on the results of the hemocytometer (de facto standard), the error rate (ER) and coefficient of variation (CV) of the NaviCell are approximately 3.27 and 2.16 times better than the commercial cell counter, respectively. The cell viability testing of the NaviCell also showed an ER and CV performance improvement of 5.09 and 1.8 times, respectively, demonstrating sufficient potential in the field of cell analysis. PMID:29286336

Simultaneous Scanning Electron Microscope Imaging of Topographical and Chemical Contrast Using In-Lens, In-Column, and Everhart-Thornley Detector Systems.

PubMed

Zhang, Xinming; Cen, Xi; Ravichandran, Rijuta; Hughes, Lauren A; van Benthem, Klaus

2016-06-01

The scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart-Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron-specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart-Thornley detector.

Smartphone adapters for digital photomicrography

PubMed Central

Roy, Somak; Pantanowitz, Liron; Amin, Milon; Seethala, Raja R.; Ishtiaque, Ahmed; Yousem, Samuel A.; Parwani, Anil V.; Cucoranu, Ioan; Hartman, Douglas J.

2014-01-01

Background: Photomicrographs in Anatomic Pathology provide a means of quickly sharing information from a glass slide for consultation, education, documentation and publication. While static image acquisition historically involved the use of a permanently mounted camera unit on a microscope, such cameras may be expensive, need to be connected to a computer, and often require proprietary software to acquire and process images. Another novel approach for capturing digital microscopic images is to use smartphones coupled with the eyepiece of a microscope. Recently, several smartphone adapters have emerged that allow users to attach mobile phones to the microscope. The aim of this study was to test the utility of these various smartphone adapters. Materials and Methods: We surveyed the market for adapters to attach smartphones to the ocular lens of a conventional light microscope. Three adapters (Magnifi, Skylight and Snapzoom) were tested. We assessed the designs of these adapters and their effectiveness at acquiring static microscopic digital images. Results: All adapters facilitated the acquisition of digital microscopic images with a smartphone. The optimal adapter was dependent on the type of phone used. The Magnifi adapters for iPhone were incompatible when using a protective case. The Snapzoom adapter was easiest to use with iPhones and other smartphones even with protective cases. Conclusions: Smartphone adapters are inexpensive and easy to use for acquiring digital microscopic images. However, they require some adjustment by the user in order to optimize focus and obtain good quality images. Smartphone microscope adapters provide an economically feasible method of acquiring and sharing digital pathology photomicrographs. PMID:25191623

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics

PubMed Central

Vallerotto, Guido; Victoria, Marta; Askins, Stephen; Antón, Ignacio; Sala, Gabriel; Herrero, Rebeca; Domínguez, César

2017-01-01

We present a method to characterize achromatic Fresnel lenses for photovoltaic applications. The achromatic doublet on glass (ADG) Fresnel lens is composed of two materials, a plastic and an elastomer, whose dispersion characteristics (refractive index variation with wavelength) are different. We first designed the lens geometry and then used ray-tracing simulation, based on the Monte Carlo method, to analyze its performance from the point of view of both optical efficiency and the maximum attainable concentration. Afterwards, ADG Fresnel lens prototypes were manufactured using a simple and reliable method. It consists of a prior injection of plastic parts and a consecutive lamination, together with the elastomer and a glass substrate to fabricate the parquet of ADG Fresnel lenses. The accuracy of the manufactured lens profile is examined using an optical microscope while its optical performance is evaluated using a solar simulator for concentrator photovoltaic systems. The simulator is composed of a xenon flash lamp whose emitted light is reflected by a parabolic mirror. The collimated light has a spectral distribution and an angular aperture similar to the real Sun. We were able to assess the optical performance of the ADG Fresnel lenses by taking photographs of the irradiance spot cast by the lens using a charge-coupled device (CCD) camera and measuring the photocurrent generated by several types of multi junction (MJ) solar cells, which have been previously characterized at a solar simulator for concentrator solar cells. These measurements have demonstrated the achromatic behavior of ADG Fresnel lenses and, as a consequence, the suitability of the modelling and manufacturing methods. PMID:29155715

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics.

PubMed

Vallerotto, Guido; Victoria, Marta; Askins, Stephen; Antón, Ignacio; Sala, Gabriel; Herrero, Rebeca; Domínguez, César

2017-10-27

We present a method to characterize achromatic Fresnel lenses for photovoltaic applications. The achromatic doublet on glass (ADG) Fresnel lens is composed of two materials, a plastic and an elastomer, whose dispersion characteristics (refractive index variation with wavelength) are different. We first designed the lens geometry and then used ray-tracing simulation, based on the Monte Carlo method, to analyze its performance from the point of view of both optical efficiency and the maximum attainable concentration. Afterwards, ADG Fresnel lens prototypes were manufactured using a simple and reliable method. It consists of a prior injection of plastic parts and a consecutive lamination, together with the elastomer and a glass substrate to fabricate the parquet of ADG Fresnel lenses. The accuracy of the manufactured lens profile is examined using an optical microscope while its optical performance is evaluated using a solar simulator for concentrator photovoltaic systems. The simulator is composed of a xenon flash lamp whose emitted light is reflected by a parabolic mirror. The collimated light has a spectral distribution and an angular aperture similar to the real Sun. We were able to assess the optical performance of the ADG Fresnel lenses by taking photographs of the irradiance spot cast by the lens using a charge-coupled device (CCD) camera and measuring the photocurrent generated by several types of multi junction (MJ) solar cells, which have been previously characterized at a solar simulator for concentrator solar cells. These measurements have demonstrated the achromatic behavior of ADG Fresnel lenses and, as a consequence, the suitability of the modelling and manufacturing methods.

The Top 10 List of Gravitational Lens Candidates from the HUBBLE SPACE TELESCOPE Medium Deep Survey

NASA Astrophysics Data System (ADS)

Ratnatunga, Kavan U.; Griffiths, Richard E.; Ostrander, Eric J.

1999-05-01

A total of 10 good candidates for gravitational lensing have been discovered in the WFPC2 images from the Hubble Space Telescope (HST) Medium Deep Survey (MDS) and archival primary observations. These candidate lenses are unique HST discoveries, i.e., they are faint systems with subarcsecond separations between the lensing objects and the lensed source images. Most of them are difficult objects for ground-based spectroscopic confirmation or for measurement of the lens and source redshifts. Seven are ``strong lens'' candidates that appear to have multiple images of the source. Three are cases in which the single image of the source galaxy has been significantly distorted into an arc. The first two quadruply lensed candidates were reported by Ratnatunga et al. We report on the subsequent eight candidates and describe them with simple models based on the assumption of singular isothermal potentials. Residuals from the simple models for some of the candidates indicate that a more complex model for the potential will probably be required to explain the full structural detail of the observations once they are confirmed to be lenses. We also discuss the effective survey area that was searched for these candidate lens objects.

Methods and Devices for Space Optical Communications Using Laser Beams

NASA Technical Reports Server (NTRS)

Goorjian, Peter M. (Inventor)

2018-01-01

Light is used to communicate between objects separated by a large distance. Light beams are received in a telescopic lens assembly positioned in front of a cat's-eye lens. The light can thereby be received at various angles to be output by the cat's-eye lens to a focal plane of the cat's-eye lens, the position of the light beams upon the focal plane corresponding to the angle of the beam received. Lasers and photodetectors are distributed along this focal plane. A processor receives signals from the photodetectors, and selectively signal lasers positioned proximate the photodetectors detecting light, in order to transmit light encoding data through the cat's-eye lens and also through a telescopic lens back in the direction of the received light beams, which direction corresponds to a location upon the focal plane of the transmitting lasers.

Many Rays Are Better than Two.

ERIC Educational Resources Information Center

Grayson, Diane J.

1995-01-01

Proposes an alternative approach to locating the image formed by a lens. Two special rays are used to locate the image, then a number of other rays are drawn in to indicate that light from the object passes through every part of the lens. (MVL)

Distance measurement based on light field geometry and ray tracing.

PubMed

Chen, Yanqin; Jin, Xin; Dai, Qionghai

2017-01-09

In this paper, we propose a geometric optical model to measure the distances of object planes in a light field image. The proposed geometric optical model is composed of two sub-models based on ray tracing: object space model and image space model. The two theoretic sub-models are derived on account of on-axis point light sources. In object space model, light rays propagate into the main lens and refract inside it following the refraction theorem. In image space model, light rays exit from emission positions on the main lens and subsequently impinge on the image sensor with different imaging diameters. The relationships between imaging diameters of objects and their corresponding emission positions on the main lens are investigated through utilizing refocusing and similar triangle principle. By combining the two sub-models together and tracing light rays back to the object space, the relationships between objects' imaging diameters and corresponding distances of object planes are figured out. The performance of the proposed geometric optical model is compared with existing approaches using different configurations of hand-held plenoptic 1.0 cameras and real experiments are conducted using a preliminary imaging system. Results demonstrate that the proposed model can outperform existing approaches in terms of accuracy and exhibits good performance at general imaging range.

Q: How do Microscopes Work?

ERIC Educational Resources Information Center

Zimov, Sarah

2004-01-01

Microscopes allow scientists to examine everyday objects in extraordinary ways. They provide high-resolution images that show objects in fine detail. This brief article describes the many types of microscopes and how they are used in different scientific venues.

Design and analysis of all-dielectric subwavelength focusing flat lens

NASA Astrophysics Data System (ADS)

Turduev, M.; Bor, E.; Kurt, H.

2017-09-01

In this letter, we numerically designed and experimentally demonstrated a compact photonic structure for the subwavelength focusing of light using all-dielectric absorption-free and nonmagnetic scattering objects distributed in an air medium. In order to design the subwavelength focusing flat lens, an evolutionary algorithm is combined with the finite-difference time-domain method for determining the locations of cylindrical scatterers. During the multi-objective optimization process, a specific objective function is defined to reduce the full width at half maximum (FWHM) and diminish side lobe level (SLL) values of light at the focal point. The time-domain response of the optimized flat lens exhibits subwavelength light focusing with an FWHM value of 0.19λ and an SLL value of 0.23, where λ denotes the operating wavelength of light. Experimental analysis of the proposed flat lens is conducted in a microwave regime and findings exactly verify the numerical results with an FWHM of 0.192λ and an SLL value of 0.311 at the operating frequency of 5.42 GHz. Moreover, the designed flat lens provides a broadband subwavelength focusing effect with a 9% bandwidth covering frequency range of 5.10 GHz-5.58 GHz, where corresponding FWHM values remain under 0.21λ. Also, it is important to note that the designed flat lens structure performs a line focusing effect. Possible applications of the designed structure in telecom wavelengths are speculated upon for future perspectives. Namely, the designed structure can perform well in photonic integrated circuits for different fields of applications such as high efficiency light coupling, imaging and optical microscopy, with its compact size and ability for strong focusing.

Auricular burns associated with operating microscope use during otologic surgery.

PubMed

Latuska, Richard F; Carlson, Matthew L; Neff, Brian A; Driscoll, Colin L; Wanna, George B; Haynes, David S

2014-02-01

To raise awareness of the potential hazard of auricular burns associated with operating microscope use during otologic surgery. Retrospective case series and summary of the Food and Drug Administration's (FDA) Manufacturer and User Facility Device Experience (MAUDE) database of voluntary adverse event reports pertaining to microscope related auricular thermal injuries. All patients who sustained auricular burns while using the operating microscope during otologic surgery at 2 tertiary academic referral centers. Surgical procedure, microscope model, intensity of illumination, length of procedure, focal length, location and severity of burn, and patient outcome. A total of 4 microscope-related auricular thermal injuries were identified from the authors' institutions. Additionally, 82 unique cases of soft tissue burns associated with the use of an operative microscope have been voluntarily reported to the FDA since 2004. A disproportionately large percent (∼ 30%) of these occurred within the field of otology, the majority of which were during tympanoplasty or tympanomastoidectomy procedures at focal length distances of 300 mm or less with xenon light source microscopes. Simultaneous advancements in light delivery technologies and lens optics have continued to improve the efficiency of the operating microscope; however, these improvements also increase the potential for thermal injuries. Although rare, a review of the FDA MAUDE database suggests that microscope-related soft tissue burns occur more frequently in otology than any other surgical specialty. A variety of factors may help explain this finding, including the unique anatomy of the external ear with thin skin and limited underlying adipose tissue. Preventative measures should be taken to decrease the risk of thermal injuries including use of the lowest comfortable light intensity, adjusting the aperture width to match the operative field, frequent wound irrigation, and covering exposed portions of the pinna with a moist surgical sponge.

Method and apparatus for a high-resolution three dimensional confocal scanning transmission electron microscope

DOEpatents

de Jonge, Niels [Oak Ridge, TN

2010-08-17

A confocal scanning transmission electron microscope which includes an electron illumination device providing an incident electron beam propagating in a direction defining a propagation axis, and a precision specimen scanning stage positioned along the propagation axis and movable in at least one direction transverse to the propagation axis. The precision specimen scanning stage is configured for positioning a specimen relative to the incident electron beam. A projector lens receives a transmitted electron beam transmitted through at least part of the specimen and focuses this transmitted beam onto an image plane, where the transmitted beam results from the specimen being illuminated by the incident electron beam. A detection system is placed approximately in the image plane.

Scanning near-field optical microscopy.

PubMed

Vobornik, Dusan; Vobornik, Slavenka

2008-02-01

An average human eye can see details down to 0,07 mm in size. The ability to see smaller details of the matter is correlated with the development of the science and the comprehension of the nature. Today's science needs eyes for the nano-world. Examples are easily found in biology and medical sciences. There is a great need to determine shape, size, chemical composition, molecular structure and dynamic properties of nano-structures. To do this, microscopes with high spatial, spectral and temporal resolution are required. Scanning Near-field Optical Microscopy (SNOM) is a new step in the evolution of microscopy. The conventional, lens-based microscopes have their resolution limited by diffraction. SNOM is not subject to this limitation and can offer up to 70 times better resolution.

Conceptual design study of a 5 kilowatt solar dynamic Brayton power system using a dome Fresnel lens solar concentrator

NASA Technical Reports Server (NTRS)

Oneill, Mark J.; Mcdanal, A. J.; Spears, Don H.

1989-01-01

The primary project objective was to generate a conceptual design for a nominal 5 kW solar dynamic space power system, which uses a unique, patented, transmittance-optimized, dome-shaped, point-focus Fresnel lens as the optical concentrator. Compared to reflective concentrators, the dome lens allows 200 times larger slope errors for the same image displacement. Additionally, the dome lens allows the energy receiver, the power conversion unit (PCU), and the heat rejection radiator to be independently optimized in configuration and orientation, since none of these elements causes any aperture blockage. Based on optical and thermal trade studies, a 6.6 m diameter lens with a focal length of 7.2 m was selected. This lens should provide 87 percent net optical efficienty at 800X geometric concentration ratio. The large lens is comprised of 24 gores, which compactly stow together during launch, and automatically deploy on orbit. The total mass of the microglass lens panels, the graphite/epoxy support structure, and miscellaneous hardware is about 1.2 kg per square meter of aperture. The key problem for the dome lens approach relates to the selection of a space-durable lens material. For the first time, all-glass Fresnel lens samples were successfully made by a sol-gel casting process.

Zoom microscope objective using electrowetting lenses.

PubMed

Li, Lei; Wang, Di; Liu, Chao; Wang, Qiong-Hua

2016-02-08

We report a zoom microscope objective which can achieve continuous zoom change and correct the aberrations dynamically. The objective consists of three electrowetting liquid lenses and two glass lenses. The magnification is changed by applying voltages on the three electrowetting lenses. Besides, the three electrowetting liquid lenses can play a role to correct the aberrations. A digital microscope based on the proposed objective is demonstrated. We analyzed the properties of the proposed objective. In contrast to the conventional objectives, the proposed objective can be tuned from ~7.8 × to ~13.2 × continuously. For our objective, the working distance is fixed, which means no movement parts are needed to refocus or change its magnification. Moreover, the zoom objective can be dynamically optimized for a wide range of wavelength. Using such an objective, the fabrication tolerance of the optical system is larger than that of a conventional system, which can decrease the fabrication cost. The proposed zoom microscope objective cannot only take place of the conventional objective, but also has potential application in the 3D microscopy.

Simulation design of light field imaging based on ZEMAX

NASA Astrophysics Data System (ADS)

Zhou, Ke; Xiao, Xiangguo; Luan, Yadong; Zhou, Xiaobin

2017-02-01

Based on the principium of light field imaging, there designed a objective lens and a microlens array for gathering the light field feature, the homologous ZEMAX models was also be built. Then all the parameters were optimized using ZEMAX and the simulation image was given out. It pointed out that the position relationship between the objective lens and the microlens array had a great affect on imaging, which was the guidance when developing a prototype.

Bacterial adhesion to unworn and worn silicone hydrogel lenses.

PubMed

Vijay, Ajay Kumar; Zhu, Hua; Ozkan, Jerome; Wu, Duojia; Masoudi, Simin; Bandara, Rani; Borazjani, Roya N; Willcox, Mark D P

2012-08-01

The objective of this study was to determine the bacterial adhesion to various silicone hydrogel lens materials and to determine whether lens wear modulated adhesion. Bacterial adhesion (total and viable cells) of Staphylococcus aureus (31, 38, and ATCC 6538) and Pseudomonas aeruginosa (6294, 6206, and GSU-3) to 10 commercially available different unworn and worn silicone hydrogel lenses was measured. Results of adhesion were correlated to polymer and surface properties of contact lenses. S. aureus adhesion to unworn lenses ranged from 2.8 × 10 to 4.4 × 10 colony forming units per lens. The highest adhesion was to lotrafilcon A lenses, and the lowest adhesion was to asmofilcon A lenses. P. aeruginosa adhesion to unworn lenses ranged from 8.9 × 10 to 3.2 × 10 colony forming units per lens. The highest adhesion was to comfilcon A lenses, and the lowest adhesion was to asmofilcon A and balafilcon A lenses. Lens wear altered bacterial adhesion, but the effect was specific to lens and strain type. Adhesion of bacteria, regardless of genera/species or lens wear, was generally correlated with the hydrophobicity of the lens; the less hydrophobic the lens surface, the greater the adhesion. P. aeruginosa adhered in higher numbers to lenses in comparison with S. aureus strains, regardless of the lens type or lens wear. The effect of lens wear was specific to strain and lens. Hydrophobicity of the silicone hydrogel lens surface influenced the adhesion of bacterial cells.

A systematic assessment of goblet cell sampling of the bulbar conjunctiva by impression cytology.

PubMed

Doughty, Michael J

2015-07-01

The purpose of this study was to assess the apparent goblet cell density (GCD) from conjunctival impression cytology (CIC) samples in relation to the number of conjunctival cells collected onto the filters. CIC specimens were collected from the superior-temporal bulbar conjunctiva of 16 pigmented rabbits onto Biopore (Millicell-CM) membranes, fixed with buffered glutaraldehyde and stained with Giemsa. Different numbers of microscope fields of view in each of the specimens were imaged by light microscopy using a 20× magnification objective lens (200× final magnification), and the goblet cells marked and counted. The GCD values/sq. mm were calculated. The same conjunctival region of 3 other rabbits was also prepared for transmission electron microscopy (TEM) by fixation, in situ, with the same buffered glutaraldehyde. Mean values for GCD estimates were found to vary from 399 to 1576 cells/sq. mm, depending on the image sampling and analysis strategy chosen, with the lowest inter-sample variance of around 10% being found if a maximum goblet cell count was taken on substantially multilayered regions of the CIC specimens. Counts of the number of goblet cells per 1000 visible conjunctival epithelial cells yielded a value of close to 90 (range 36-151), with modest inter-sample variability of around 30%. A three or ten 200× microscope field and random sampling strategy yielded mean GCD values between 542 and 670 cells/sq. mm, but with very high intra- and inter-sample variance of at least 60% and sometimes higher than 100%. TEM confirmed the multilayered organization of the conjunctiva and the deeper lying goblet cells. The general use of a goblet cell count as an objective marker for conjunctival normality or health is likely to be highly variable unless a more specific strategy is adopted. Beyond providing details of exactly the counting strategy used, it would be very useful to provide full details of the actual microscope field size used as well as information on the intra-sample variability in goblet cell counts. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optical design and evaluation of a 4 mm cost-effective ultra-high-definition arthroscope.

PubMed

Cheng, Dewen; Wang, Yongtian; Yu, Lu; Liu, Xiaohua

2014-08-01

High definition and magnification rigid endoscope plays an important role in modern minimally invasive medical surgery and diagnosis. In this paper, we present the design and evaluation methods of a high definition rigid endoscope, specifically an arthroscope, with a large depth of field (DOF). The incident heights and exit angles of the sampled rays on the relay lens are controlled during the optimization process to ensure an effective field view (70°) and a normal ray path within the limited lens diameter of 2.7 mm. The lens is set up as a multi-configuration system with two extreme and one middle object distances to cover a large DOF. As a result, an entrance pupil of 0.3 mm is achieved for the first time, to bring the theoretical resolution to 23.1 lps/mm in the object space at a working distance of 20 mm, with the wavelength of 0.532 um. The modulation transfer function (MTF) curves approach diffraction limit, and the values are all higher than 0.3 at 160 line pairs/mm (lps/mm) in the image space. Meanwhile, stray light caused by total internal reflection on the inner wall of the rod lenses and the objective lens is eliminated. The measured resolution in the object space at a 20 mm working distance is 22.3 lps/mm, and test results show that other performance characteristics also fulfill design requirements. The relay lenses are designed with only one type of the spacer and two types of lenses to greatly reduce the fabrication and assembly cost. The design method has important research and application values for lens systems used in modern minimally invasive medical surgery and industrial non-destructive testing area.

[Eyelid hygiene for contact lens wearers with blepharitis. Comparative investigation of treatment with baby shampoo versus phospholipid solution].

PubMed

Khaireddin, R; Hueber, A

2013-02-01

Blepharitis due to Meibom gland dysfunction (MGD) is presumed to be one of the main reasons for dry eye symptoms which occur in up to 50% of contact lens users. Thus, MGD presumably plays an important role in dry eye in contact lens wearers. In the present prospective, randomized and double blind trial the efficacy of two established treatment options for MGD and blepharitis was evaluated in symptomatic contact lens wearers. In this prospective, randomized 2-centre trial 53 symptomatic contact lens wearers suffering from blepharitis were included. Patients were randomly selected for two treatment groups: group A performed lid margin hygiene using the commonly recommended mild baby shampoo (Bübchen Kinder Shampoo-extra augenmild, Bübchen Werk Ewald Hermes Pharmazeutische Fabrik GmbH, Soest, Germany) and group B performed lid margin hygiene using a phospholipid-liposome solution specially designed for lid hygiene (Blepha Cura, Optima, Moosburg/Wang, Germany), each for 4 weeks. Before as well as 4 weeks after initiation of this study the following tests were performed: standardized subjective assessment using the ocular surface disease index, non-invasive break-up time (NIBUT) and objective evaluation of lid-parallel conjunctival folds (LIPCOF) and further lid margin criteria by double blinded evaluation of slit lamp photographs. Of the 53 symptomatic contact lens wearers suffering from blepharitis 21 (39,6%) were randomly selected for treatment group A and 32 (60.4%) for group B. In both treatment groups there was objective and subjective improvement of symptoms of dry eye in contact lens wearers. Interestingly, there was a significantly greater improvement, subjective as well as objective, in treatment group B which used the phospholipidliposome solution for lid margin hygiene compared to group A using baby shampoo. Although both therapies improved symptoms of dry eye due to blepharitis in symptomatic contact lens wearers, patients using phospholipid-liposomal solution for lid margin hygiene demonstrated a significantly greater clinical benefit from the therapy. Thus, clinical practice recommending just baby shampoo for lid margin hygiene should be re-considered, as phospholipid-liposomal solution for lid margin hygiene appears to yield greater and faster clinical benefits for symptomatic contact lens wearers suffering from dry eye symptoms.

Shaping the light for the investigation of depth-extended scattering media

NASA Astrophysics Data System (ADS)

Osten, W.; Frenner, K.; Pedrini, G.; Singh, A. K.; Schindler, J.; Takeda, M.

2018-02-01

Scattering media are an ongoing challenge for all kind of imaging technologies including coherent and incoherent principles. Inspired by new approaches of computational imaging and supported by the availability of powerful computers, spatial light modulators, light sources and detectors, a variety of new methods ranging from holography to time-of-flight imaging, phase conjugation, phase recovery using iterative algorithms and correlation techniques have been introduced and applied to different types of objects. However, considering the obvious progress in this field, several problems are still matter of investigation and their solution could open new doors for the inspection and application of scattering media as well. In particular, these open questions include the possibility of extending the 2d-approach to the inspection of depth-extended objects, the direct use of a scattering media as a simple tool for imaging of complex objects and the improvement of coherent inspection techniques for the dimensional characterization of incoherently radiating spots embedded in scattering media. In this paper we show our recent findings in coping with these challenges. First we describe how to explore depth-extended objects by means of a scattering media. Afterwards, we extend this approach by implementing a new type of microscope making use of a simple scatter plate as a kind of flat and unconventional imaging lens. Finally, we introduce our shearing interferometer in combination with structured illumination for retrieving the axial position of fluorescent light emitting spots embedded in scattering media.

Bifocal liquid lens zoom objective for mobile phone applications

NASA Astrophysics Data System (ADS)

Wippermann, F. C.; Schreiber, P.; Bräuer, A.; Craen, P.

2007-02-01

Miniaturized camera systems are an integral part of today's mobile phones which recently possess auto focus functionality. Commercially available solutions without moving parts have been developed using the electrowetting technology. Here, the contact angle of a drop of a conductive or polar liquid placed on an insulating substrate can be influenced by an electric field. Besides the compensation of the axial image shift due to different object distances, mobile phones with zoom functionality are desired as a next evolutionary step. In classical mechanically compensated zoom lenses two independently driven actuators combined with precision guides are needed leading to a delicate, space consuming and expansive opto-mechanical setup. Liquid lens technology based on the electrowetting effect gives the opportunity to built adaptive lenses without moving parts thus simplifying the mechanical setup. However, with the recent commercially available liquid lens products a completely motionless and continuously adaptive zoom system with market relevant optical performance is not feasible. This is due to the limited change in optical power the liquid lenses can provide and the dispersion of the used materials. As an intermediate step towards a continuously adjustable and motionless zoom lens we propose a bifocal system sufficient for toggling between two effective focal lengths without any moving parts. The system has its mechanical counterpart in a bifocal zoom lens where only one lens group has to be moved. In a liquid lens bifocal zoom two groups of adaptable liquid lenses are required for adjusting the effective focal length and keeping the image location constant. In order to overcome the difficulties in achromatizing the lens we propose a sequential image acquisition algorithm. Here, the full color image is obtained from a sequence of monochrome images (red, green, blue) leading to a simplified optical setup.

Annular Focused Electron/Ion Beams for Combining High Spatial Resolution with High Probe Current.

PubMed

Khursheed, Anjam; Ang, Wei Kean

2016-10-01

This paper presents a proposal for reducing the final probe size of focused electron/ion beam columns that are operated in a high primary beam current mode where relatively large final apertures are used, typically required in applications such as electron beam lithography, focused ion beams, and electron beam spectroscopy. An annular aperture together with a lens corrector unit is used to replace the conventional final hole-aperture, creating an annular ring-shaped primary beam. The corrector unit is designed to eliminate the first- and second-order geometric aberrations of the objective lens, and for the same probe current, the final geometric aberration limited spot size is predicted to be around a factor of 50 times smaller than that of the corresponding conventional hole-aperture beam. Direct ray tracing simulation is used to illustrate how a three-stage core lens corrector can be used to eliminate the first- and second-order geometric aberrations of an electric Einzel objective lens.

Dynamic light scattering as an objective noninvasive method in veterinary ophthalmic diagnosis and research

NASA Astrophysics Data System (ADS)

Dubin, Stephen; Ansari, Rafat R.; Tulp, Orien; Steinberg, Sheldon; Koch, Seth; DellaVecchia, Michael A.; Cozmi, Mihaela; Victor, Mary

1999-06-01

The absence of verbal feedback, available from most human patients, is a major limitation in veterinary diagnosis in general and in the evaluation of ophthalmic lens opacity in particular. A novel compact dynamic light scattering (DLS) instrument, developed at NASA, offers significant mitigation to this limitation. It not only yields objective repeatable non-invasive estimation of lens opacity but also provides insight into the nature of chemical and physical alternations in the lens and other eye structures. For example, DLS measurements of the cataractous lens may be interpreted in terms of alpha crystalline protein size. In contrast to most conventional methods, the examination results are numerical and readily accommodate statistical analysis. We present results of DLS measurements in laboratory rabbits with naphthalene induced cataracts, rodents with genetically conditioned hypertension and/or diabetes mellitus; as well as applications of the DLS method in clinical veterinary patients. Use of DLS in examination of phacoemulsification fluid, urine and other biological materials, and potential applications in ocular toxically will also be discussed.

Realization of integral 3-dimensional image using fabricated tunable liquid lens array

NASA Astrophysics Data System (ADS)

Lee, Muyoung; Kim, Junoh; Kim, Cheol Joong; Lee, Jin Su; Won, Yong Hyub

2015-03-01

Electrowetting has been widely studied for various optical applications such as optical switch, sensor, prism, and display. In this study, vari-focal liquid lens array is developed using electrowetting principle to construct integral 3-dimensional imaging. The electrowetting principle that changes the surface tension by applying voltage has several advantages to realize active optical device such as fast response time, low electrical consumption, and no mechanical moving parts. Two immiscible liquids that are water and oil are used for forming lens. By applying a voltage to the water, the focal length of the lens could be tuned as changing contact angle of water. The fabricated electrowetting vari-focal liquid lens array has 1mm diameter spherical lens shape that has 1.6mm distance between each lens. The number of lenses on the panel is 23x23 and the focal length of the lens array is simultaneously tuned from -125 to 110 diopters depending on the applied voltage. The fabricated lens array is implemented to integral 3-dimensional imaging. A 3D object is reconstructed by fabricated liquid lens array with 23x23 elemental images that are generated by 3D max tools. When liquid lens array is tuned as convex state. From vari-focal liquid lens array implemented integral imaging system, we expect that depth enhanced integral imaging can be realized in the near future.

Monitoring synaptic and neuronal activity in 3D with synthetic and genetic indicators using a compact acousto-optic lens two-photon microscope☆

PubMed Central

Fernández-Alfonso, Tomás; Nadella, K.M. Naga Srinivas; Iacaruso, M. Florencia; Pichler, Bruno; Roš, Hana; Kirkby, Paul A.; Silver, R. Angus

2014-01-01

Background Two-photon microscopy is widely used to study brain function, but conventional microscopes are too slow to capture the timing of neuronal signalling and imaging is restricted to one plane. Recent development of acousto-optic-deflector-based random access functional imaging has improved the temporal resolution, but the utility of these technologies for mapping 3D synaptic activity patterns and their performance at the excitation wavelengths required to image genetically encoded indicators have not been investigated. New method Here, we have used a compact acousto-optic lens (AOL) two-photon microscope to make high speed [Ca2+] measurements from spines and dendrites distributed in 3D with different excitation wavelengths (800–920 nm). Results We show simultaneous monitoring of activity from many synaptic inputs distributed over the 3D arborisation of a neuronal dendrite using both synthetic as well as genetically encoded indicators. We confirm the utility of AOL-based imaging for fast in vivo recordings by measuring, simultaneously, visually evoked responses in 100 neurons distributed over a 150 μm focal depth range. Moreover, we explore ways to improve the measurement of timing of neuronal activation by choosing specific regions within the cell soma. Comparison with existing methods These results establish that AOL-based 3D random access two-photon microscopy has a wider range of neuroscience applications than previously shown. Conclusions Our findings show that the compact AOL microscope design has the speed, spatial resolution, sensitivity and wavelength flexibility to measure 3D patterns of synaptic and neuronal activity on individual trials. PMID:24200507

Electrowetting-actuated zoom lens with spherical-interface liquid lenses.

PubMed

Peng, Runling; Chen, Jiabi; Zhuang, Songlin

2008-11-01

The interface shape of two immiscible liquids in a conical chamber is discussed. The analytical solution of the differential equation describing the interface shape shows that the interface shape is completely spherical when the density difference of two liquids is zero. On the basis of the spherical-interface shape and an energy-minimization method, explicit calculations and detailed analyses of an extended Young-type equation for the conical double-liquid lens are given. Finally, a novel design of a zoom lens system without motorized movements is proposed. The lens system consists of a fixed lens and two conical double-liquid variable-focus lenses. The structure and principle of the lens system are introduced in this paper. Taking finite objects as example, detailed calculations and simulation examples are presented to predict how two liquid lenses are related to meet the basic requirements of zoom lenses.

Reconstruction of refocusing and all-in-focus images based on forward simulation model of plenoptic camera

NASA Astrophysics Data System (ADS)

Zhang, Rumin; Liu, Peng; Liu, Dijun; Su, Guobin

2015-12-01

In this paper, we establish a forward simulation model of plenoptic camera which is implemented by inserting a micro-lens array in a conventional camera. The simulation model is used to emulate how the space objects at different depths are imaged by the main lens then remapped by the micro-lens and finally captured on the 2D sensor. We can easily modify the parameters of the simulation model such as the focal lengths and diameters of the main lens and micro-lens and the number of micro-lens. Employing the spatial integration, the refocused images and all-in-focus images are rendered based on the plenoptic images produced by the model. The forward simulation model can be used to determine the trade-offs between different configurations and to test any new researches related to plenoptic camera without the need of prototype.

eV-TEM: Transmission electron microscopy in a low energy cathode lens instrument.

PubMed

Geelen, Daniël; Thete, Aniket; Schaff, Oliver; Kaiser, Alexander; van der Molen, Sense Jan; Tromp, Rudolf

2015-12-01

We are developing a transmission electron microscope that operates at extremely low electron energies, 0-40 eV. We call this technique eV-TEM. Its feasibility is based on the fact that at very low electron energies the number of energy loss pathways decreases. Hence, the electron inelastic mean free path increases dramatically. eV-TEM will enable us to study elastic and inelastic interactions of electrons with thin samples. With the recent development of aberration correction in cathode lens instruments, a spatial resolution of a few nm appears within range, even for these very low electron energies. Such resolution will be highly relevant to study biological samples such as proteins and cell membranes. The low electron energies minimize adverse effects due to radiation damage. Copyright © 2015. Published by Elsevier B.V.

Laser-assisted marking for toric intraocular lens alignment.

PubMed

Dick, H Burkhard; Schultz, Tim

2016-01-01

We describe a technique of 3-dimensional spectral-domain optical coherence tomography-controlled laser-assisted corneal marking for toric intraocular lens implantation. To facilitate accurate alignment, the technique creates 2 perpendicular intrastromal incisions (width 0.75 mm) using an image-guided femtosecond laser. This was performed in a case series comprising 10 eyes of 10 patients. No posterior corneal perforation or epithelial alterations occurred. The incisions were plainly visible under the operating microscope, and no optical phenomena were reported 6 weeks after surgery. Laser-assisted marking can be performed safely and has the potential to enable precise axis marking. Dr. Dick is a paid consultant to Abbott Medical Optics, Inc. Dr. Schultz has no financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Design of laser afocal zoom expander system

NASA Astrophysics Data System (ADS)

Jiang, Lian; Zeng, Chun-Mei; Hu, Tian-Tian

2018-01-01

Laser afocal zoom expander system due to the beam diameter variable, can be used in the light sheet illumination microscope to observe the samples of different sizes. Based on the principle of afocal zoom system, the laser collimation and beam expander system with a total length of less than 110mm, 6 pieces of spherical lens and a beam expander ratio of 10 is designed by using Zemax software. The system is focused on laser with a wavelength of 532nm, divergence angle of less than 4mrad and incident diameter of 4mm. With the combination of 6 spherical lens, the beam divergence angle is 0.4mrad at the maximum magnification ratio, and the RMS values at different rates are less than λ/4. This design is simple in structure and easy to process and adjust. It has certain practical value.

Scanning electron microscopy analysis of a sputnik-like intraocular lens 28 years after implantation.

PubMed

Ferrer, Consuelo; Abu-Mustafa, Sabat K; Alió, Jorge L

2009-09-01

To report a pupil-supported, iris-clip intraocular lens (IOL) that was explanted more than 28 years after implantation. A pupil-supported, iris-clip, Sputnik-like IOL was implanted in the left eye of a 33-year-old man to correct aphakia after extracapsular cataract extraction due to trauma. Twenty-eight years after implantation, the patient was referred to our center with loss of vision. Clinical examination showed dislocation of the IOL, which was subsequently explanted. Scanning electron microscopic examination showed a transparent, polymethylmethacrylate (PMMA), pupil-supported, iris-clip IOL with melanosomes and cell deposits (foreign-body reaction) on its surface. This case demonstrates the inertness of PMMA material and reports that a foreign body reaction can be induced following IOL dislocation 28 years after implantation. Copyright 2009, SLACK Incorporated.

Collection efficiency and acceptance maps of electron detectors for understanding signal detection on modern scanning electron microscopy.

PubMed

Agemura, Toshihide; Sekiguchi, Takashi

2018-02-01

Collection efficiency and acceptance maps of typical detectors in modern scanning electron microscopes (SEMs) were investigated. Secondary and backscattered electron trajectories from a specimen to through-the-lens and under-the-lens detectors placed on an electron optical axis and an Everhart-Thornley detector mounted on a specimen chamber were simulated three-dimensionally. The acceptance maps were drawn as the relationship between the energy and angle of collected electrons under different working distances. The collection efficiency considering the detector sensitivity was also estimated for the various working distances. These data indicated that the acceptance maps and collection efficiency are keys to understand the detection mechanism and image contrast for each detector in the modern SEMs. Furthermore, the working distance is the dominant parameter because electron trajectories are drastically changed with the working distance.

Handheld tunable focus confocal microscope utilizing a double-clad fiber coupler for in vivo imaging of oral epithelium

PubMed Central

Olsovsky, Cory; Hinsdale, Taylor; Cuenca, Rodrigo; Cheng, Yi-Shing Lisa; Wright, John M.; Rees, Terry D.; Jo, Javier A.; Maitland, Kristen C.

2017-01-01

Abstract. A reflectance confocal endomicroscope with double-clad fiber coupler and electrically tunable focus lens is applied to imaging of the oral mucosa. The instrument is designed to be lightweight and robust for clinical use. The tunable lens allows axial scanning through >250  μm in the epithelium when the probe tip is placed in contact with tissue. Images are acquired at 6.6 frames per second with a field of view diameter up to 850  μm. In vivo imaging of a wide range of normal sites in the oral cavity demonstrates the accessibility of the handheld probe. In vivo imaging of clinical lesions diagnosed as inflammation and dysplasia illustrates the ability of reflectance confocal endomicroscopy to image cellular changes associated with pathology. PMID:28541447

Design of tracking and detecting lens system by diffractive optical method

NASA Astrophysics Data System (ADS)

Yang, Jiang; Qi, Bo; Ren, Ge; Zhou, Jianwei

2016-10-01

Many target-tracking applications require an optical system to acquire the target for tracking and identification. This paper describes a new detecting optical system that can provide automatic flying object detecting, tracking and measuring in visible band. The main feature of the detecting lens system is the combination of diffractive optics with traditional lens design by a technique was invented by Schupmann. Diffractive lens has great potential for developing the larger aperture and lightweight lens. First, the optical system scheme was described. Then the Schupmann achromatic principle with diffractive lens and corrective optics is introduced. According to the technical features and requirements of the optical imaging system for detecting and tracking, we designed a lens system with flat surface Fresnel lens and cancels the optical system chromatic aberration by another flat surface Fresnel lens with effective focal length of 1980mm, an F-Number of F/9.9 and a field of view of 2ωω = 14.2', spatial resolution of 46 lp/mm and a working wavelength range of 0.6 0.85um. At last, the system is compact and easy to fabricate and assembly, the diffuse spot size and MTF function and other analysis provide good performance.

Commentary: Giuseppe Campani (1635-1715, Rome, Italy): the First Use of a Microscope in Medicine and Surgery.

PubMed

Brogna, Christian; Millesi, Matthias; Fiengo, Leslie; Richardson, Mark; Bhangoo, Ranjeev; Ashkan, Keyoumars; Türe, Ugur

2018-02-01

Giuseppe Campani (1635-1715) was a polymath in Rome, Italy, during the Scientific Revolution in the XVIIth century. In particular, he forged the screw barrel microscope and was manufacturing his own lenses for microscopes and telescopes. He mastered the art of lens grinding. Those lenses have been analyzed with modern methods and turned out to be of extremely good quality, shining light on the fact that Giuseppe Campani mastered the theories of optics. Moreover, in a letter that Giuseppe Campani sent to Pope Innocent XI, he clearly described the use of a microscope for the examination of wounds of legs. This letter dates back to 15 August 1686 and is the first evidence of the use of microscopes to analyze wounds, sores, and anatomic specimens in medical and surgical settings. MG Yasargil previously showed the lithography accompanying this letter and was the first to recognize its great importance. We accessed this original letter in the Vatican Library, and for the first time we have translated it from Latin to English in order to unveil its significance in the context of the Scientific Revolution and the history of medicine and surgery. Copyright © 2017 by the Congress of Neurological Surgeons.