Large-field-of-view, modular, stabilized, adaptive-optics-based scanning laser ophthalmoscope.

PubMed

Burns, Stephen A; Tumbar, Remy; Elsner, Ann E; Ferguson, Daniel; Hammer, Daniel X

2007-05-01

We describe the design and performance of an adaptive optics retinal imager that is optimized for use during dynamic correction for eye movements. The system incorporates a retinal tracker and stabilizer, a wide-field line scan scanning laser ophthalmoscope (SLO), and a high-resolution microelectromechanical-systems-based adaptive optics SLO. The detection system incorporates selection and positioning of confocal apertures, allowing measurement of images arising from different portions of the double pass retinal point-spread function (psf). System performance was excellent. The adaptive optics increased the brightness and contrast for small confocal apertures by more than 2x and decreased the brightness of images obtained with displaced apertures, confirming the ability of the adaptive optics system to improve the psf. The retinal image was stabilized to within 18 microm 90% of the time. Stabilization was sufficient for cross-correlation techniques to automatically align the images.

Setup errors and effectiveness of Optical Laser 3D Surface imaging system (Sentinel) in postoperative radiotherapy of breast cancer.

PubMed

Wei, Xiaobo; Liu, Mengjiao; Ding, Yun; Li, Qilin; Cheng, Changhai; Zong, Xian; Yin, Wenming; Chen, Jie; Gu, Wendong

2018-05-08

Breast-conserving surgery (BCS) plus postoperative radiotherapy has become the standard treatment for early-stage breast cancer. The aim of this study was to compare the setup accuracy of optical surface imaging by the Sentinel system with cone-beam computerized tomography (CBCT) imaging currently used in our clinic for patients received BCS. Two optical surface scans were acquired before and immediately after couch movement correction. The correlation between the setup errors as determined by the initial optical surface scan and CBCT was analyzed. The deviation of the second optical surface scan from the reference planning CT was considered an estimate for the residual errors for the new method for patient setup correction. The consequences in terms for necessary planning target volume (PTV) margins for treatment sessions without setup correction applied. We analyzed 145 scans in 27 patients treated for early stage breast cancer. The setup errors of skin marker based patient alignment by optical surface scan and CBCT were correlated, and the residual setup errors as determined by the optical surface scan after couch movement correction were reduced. Optical surface imaging provides a convenient method for improving the setup accuracy for breast cancer patient without unnecessary imaging dose.

Fast ultra-wideband microwave spectral scanning utilizing photonic wavelength- and time-division multiplexing.

PubMed

Li, Yihan; Kuse, Naoya; Fermann, Martin

2017-08-07

A high-speed ultra-wideband microwave spectral scanning system is proposed and experimentally demonstrated. Utilizing coherent dual electro-optical frequency combs and a recirculating optical frequency shifter, the proposed system realizes wavelength- and time-division multiplexing at the same time, offering flexibility between scan speed and size, weight and power requirements (SWaP). High-speed spectral scanning spanning from ~1 to 8 GHz with ~1.2 MHz spectral resolution is achieved experimentally within 14 µs. The system can be easily scaled to higher bandwidth coverage, faster scanning speed or finer spectral resolution with suitable hardware.

Three-Dimensional Optical Coherence Tomography

NASA Technical Reports Server (NTRS)

Gutin, Mikhail; Wang, Xu-Ming; Gutin, Olga

2009-01-01

Three-dimensional (3D) optical coherence tomography (OCT) is an advanced method of noninvasive infrared imaging of tissues in depth. Heretofore, commercial OCT systems for 3D imaging have been designed principally for external ophthalmological examination. As explained below, such systems have been based on a one-dimensional OCT principle, and in the operation of such a system, 3D imaging is accomplished partly by means of a combination of electronic scanning along the optical (Z) axis and mechanical scanning along the two axes (X and Y) orthogonal to the optical axis. In 3D OCT, 3D imaging involves a form of electronic scanning (without mechanical scanning) along all three axes. Consequently, the need for mechanical adjustment is minimal and the mechanism used to position the OCT probe can be correspondingly more compact. A 3D OCT system also includes a probe of improved design and utilizes advanced signal- processing techniques. Improvements in performance over prior OCT systems include finer resolution, greater speed, and greater depth of field.

Rotary-scanning optical resolution photoacoustic microscopy

NASA Astrophysics Data System (ADS)

Qi, Weizhi; Xi, Lei

2016-10-01

Optical resolution photoacoustic microscopy (ORPAM) is currently one of the fastest evolving photoacoustic imaging modalities. It has a comparable spatial resolution to pure optical microscopic techniques such as epifluorescence microscopy, confocal microscopy, and two-photon microscopy, but also owns a deeper penetration depth. In this paper, we report a rotary-scanning (RS)-ORPAM that utilizes a galvanometer scanner integrated with objective to achieve rotary laser scanning. A 15 MHz cylindrically focused ultrasonic transducer is mounted onto a motorized rotation stage to follow optical scanning traces synchronously. To minimize the loss of signal to noise ratio, the acoustic focus is precisely adjusted to reach confocal with optical focus. Black tapes and carbon fibers are firstly imaged to evaluate the performance of the system, and then in vivo imaging of vasculature networks inside the ears and brains of mice is demonstrated using this system.

Large Field of View, Modular, Stabilized, Adaptive-Optics-Based Scanning Laser Ophthalmoscope

PubMed Central

Burns, Stephen A.; Tumbar, Remy; Elsner, Ann E.; Ferguson, Daniel; Hammer, Daniel X.

2007-01-01

We describe the design and performance of an adaptive optics retinal imager that is optimized for use during dynamic correction for eye movements. The system incorporates a retinal tracker and stabilizer, a wide field line scan Scanning Laser Ophthalmocsope (SLO), and a high resolution MEMS based adaptive optics SLO. The detection system incorporates selection and positioning of confocal apertures, allowing measurement of images arising from different portions of the double pass retinal point spread function (psf). System performance was excellent. The adaptive optics increased the brightness and contrast for small confocal apertures by more than 2x, and decreased the brightness of images obtained with displaced apertures, confirming the ability of the adaptive optics system to improve the pointspread function. The retinal image was stabilized to within 18 microns 90% of the time. Stabilization was sufficient for cross-correlation techniques to automatically align the images. PMID:17429477

Development of a compact optical MEMS scanner with integrated VCSEL light source and diffractive optics

NASA Astrophysics Data System (ADS)

Krygowski, Thomas W.; Reyes, David; Rodgers, M. Steven; Smith, James H.; Warren, Mial E.; Sweatt, William C.; Blum-Spahn, Olga; Wendt, Joel R.; Asbill, Randolph E.

1999-09-01

In this work the design and initial fabrication results are reported for the components of a compact optical-MEMS laser scanning system. This system integrates a silicon MEMS laser scanner, a Vertical Cavity Surface Emitting Laser (VCSEL) and passive optical components. The MEMS scanner and VCSEL are mounted onto a fused silica substrate which serves as an optical interconnect between the devices. Two Diffractive Optical Elements (DOE's) are etched into the fused silica substrate to focus the VCSEL beam and increase the scan range. The silicon MEMS scanner consists of an actuator that continuously scans the position of a large polysilicon gold- coated shuttle containing a third DOE. Interferometric measurements show that the residual stress in the 50 micrometer X 1000 micrometer shuttle is extremely low, with a maximum deflection of only 0.18 micrometer over an 800 micrometer span for an unmetallized case and a deflection of 0.56 micrometer for the metallized case. A conservative estimate for the scan range is approximately plus or minus 4 degrees, with a spot size of about 0.5 mm, producing 50 resolvable spots. The basic system architecture, optical and MEMS design is reported in this paper, with an emphasis on the design and fabrication of the silicon MEMS scanner portion of the system.

Proof of concept demonstration for coherent beam pattern measurements of KID detectors

NASA Astrophysics Data System (ADS)

Davis, Kristina K.; Baryshev, Andrey M.; Jellema, Willem; Yates, Stephen J. C.; Ferrari, Lorenza; Baselmans, Jochem J. A.

2016-07-01

Here we summarize the initial results from a complex field radiation pattern measurement of a kinetic inductance detector instrument. These detectors are phase insensitive and have thus been limited to scalar, or amplitude-only, beam measurements. Vector beam scans, of both amplitude and phase, double the information received in comparison to scalar beam scans. Scalar beam measurements require multiple scans at varying distances along the optical path of the receiver to fully constrain the divergence angle of the optical system and locate the primary focus. Vector scans provide this information with a single scan, reducing the total measurement time required for new systems and also limiting the influence of system instabilities. The vector scan can be taken at any point along the optical axis of the system including the near-field, which makes beam measurements possible for large systems at high frequencies where these measurements may be inconceivable to be tested in-situ. Therefore, the methodology presented here should enable common heterodyne analysis for direct detector instruments. In principle, this coherent measurement strategy allows phase dependent analysis to be performed on any direct-detect receiver instrument.

Calibration of Viking imaging system pointing, image extraction, and optical navigation measure

NASA Technical Reports Server (NTRS)

Breckenridge, W. G.; Fowler, J. W.; Morgan, E. M.

1977-01-01

Pointing control and knowledge accuracy of Viking Orbiter science instruments is controlled by the scan platform. Calibration of the scan platform and the imaging system was accomplished through mathematical models. The calibration procedure and results obtained for the two Viking spacecraft are described. Included are both ground and in-flight scan platform calibrations, and the additional calibrations unique to optical navigation.

Lens based adaptive optics scanning laser ophthalmoscope.

PubMed

Felberer, Franz; Kroisamer, Julia-Sophie; Hitzenberger, Christoph K; Pircher, Michael

2012-07-30

We present an alternative approach for an adaptive optics scanning laser ophthalmoscope (AO-SLO). In contrast to other commonly used AO-SLO instruments, the imaging optics consist of lenses. Images of the fovea region of 5 healthy volunteers are recorded. The system is capable to resolve human foveal cones in 3 out of 5 healthy volunteers. Additionally, we investigated the capability of the system to support larger scanning angles (up to 5°) on the retina. Finally, in order to demonstrate the performance of the instrument images of rod photoreceptors are presented.

Volumetric imaging of rod and cone photoreceptor structure with a combined adaptive optics-optical coherence tomography-scanning laser ophthalmoscope

NASA Astrophysics Data System (ADS)

Wells-Gray, Elaine M.; Choi, Stacey S.; Zawadzki, Robert J.; Finn, Susanna C.; Greiner, Cherry; Werner, John S.; Doble, Nathan

2018-03-01

We have designed and implemented a dual-mode adaptive optics (AO) imaging system that combines spectral domain optical coherence tomography (OCT) and scanning laser ophthalmoscopy (SLO) for in vivo imaging of the human retina. The system simultaneously acquires SLO frames and OCT B-scans at 60 Hz with an OCT volume acquisition time of 4.2 s. Transverse eye motion measured from the SLO is used to register the OCT B-scans to generate three-dimensional (3-D) volumes. Key optical design considerations include: minimizing system aberrations through the use of off-axis relay telescopes, conjugate pupil plane requirements, and the use of dichroic beam splitters to separate and recombine the OCT and SLO beams around the nonshared horizontal scanning mirrors. To demonstrate system performance, AO-OCT-SLO images and measurements are taken from three normal human subjects ranging in retinal eccentricity from the fovea out to 15-deg temporal and 20-deg superior. Also presented are en face OCT projections generated from the registered 3-D volumes. The ability to acquire high-resolution 3-D images of the human retina in the midperiphery and beyond has clinical importance in diseases, such as retinitis pigmentosa and cone-rod dystrophy.

An Evaluation of PC-Based Optical Character Recognition Systems.

ERIC Educational Resources Information Center

Schreier, E. M.; Uslan, M. M.

1991-01-01

The review examines six personal computer-based optical character recognition (OCR) systems designed for use by blind and visually impaired people. Considered are OCR components and terms, documentation, scanning and reading, command structure, conversion, unique features, accuracy of recognition, scanning time, speed, and cost. (DB)

Single lens system for forward-viewing navigation and scanning side-viewing optical coherence tomography

NASA Astrophysics Data System (ADS)

Tate, Tyler H.; McGregor, Davis; Barton, Jennifer K.

2017-02-01

The optical design for a dual modality endoscope based on piezo scanning fiber technology is presented including a novel technique to combine forward-viewing navigation and side viewing OCT. Potential applications include navigating body lumens such as the fallopian tube, biliary ducts and cardiovascular system. A custom cover plate provides a rotationally symmetric double reflection of the OCT beam to deviate and focus the OCT beam out the side of the endoscope for cross-sectional imaging of the tubal lumen. Considerations in the choice of the scanning fiber are explored and a new technique to increase the divergence angle of the scanning fiber to improve system performance is presented. Resolution and the necessary scanning density requirements to achieve Nyquist sampling of the full image are considered. The novel optical design lays the groundwork for a new approach integrating side-viewing OCT into multimodality endoscopes for small lumen imaging. KEYWORDS:

Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE)

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K.

1998-01-01

Scanning holographic lidar receivers are currently in use in two operational lidar systems, PHASERS (Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing) and now HARLIE (Holographic Airborne Rotating Lidar Instrument Experiment). These systems are based on volume phase holograms made in dichromated gelatin (DCG) sandwiched between 2 layers of high quality float glass. They have demonstrated the practical application of this technology to compact scanning lidar systems at 532 and 1064 nm wavelengths, the ability to withstand moderately high laser power and energy loading, sufficient optical quality for most direct detection systems, overall efficiencies rivaling conventional receivers, and the stability to last several years under typical lidar system environments. Their size and weight are approximately half of similar performing scanning systems using reflective optics. The cost of holographic systems will eventually be lower than the reflective optical systems depending on their degree of commercialization. There are a number of applications that require or can greatly benefit from a scanning capability. Several of these are airborne systems, which either use focal plane scanning, as in the Laser Vegetation Imaging System or use primary aperture scanning, as in the Airborne Oceanographic Lidar or the Large Aperture Scanning Airborne Lidar. The latter class requires a large clear aperture opening or window in the aircraft. This type of system can greatly benefit from the use of scanning transmission holograms of the HARLIE type because the clear aperture required is only about 25% larger than the collecting aperture as opposed to 200-300% larger for scan angles of 45 degrees off nadir.

Versatile optical system for static and dynamic thermomagnetic recording using a scanning laser microscope

NASA Astrophysics Data System (ADS)

Clegg, Warwick W.; Jenkins, David F. L.; Helian, Na; Windmill, James; Windmill, Robert

2001-12-01

Scanning Laser Microscopes (SLM) have been used to characterise the magnetic domain properties of various magnetic and magneto-optical materials. The SLM in our laboratory has been designed to enable both static and dynamic read-write operations to be performed on stationary media. In a conventional (static) SLM, data bits are recorded thermo-magnetically by focusing a pulse of laser light onto the sample surface. If the laser beam has a Gaussian intensity distribution (TEM00) then so will the focused laser spot. The resultant temperature profile will largely mirror the intensity distribution of the focused spot, and in the region where the temperature is sufficiently high for switching to occur, in the presence of bias field, a circular data bit will be recorded. However, in a real magneto-optical drive the bits are written onto non-stationary media, and the resultant bit will be non-circular. A versatile optical system has been developed to facilitate both recording and imaging of data bits. To simulate the action of a Magneto-Optical drive, the laser is pulsed via an Acousto-Optic Modulator, whilst being scanned across the sample using a galvanometer mounted mirror, thus imitating a storage medium rotating above a MO head with high relative velocity between the beam and medium. Static recording is simply achieved by disabling the galvanometer scan mirror. Polar magneto-optic Kerr effect images are acquired using multiple-segment photo-detectors for diffraction-limited scanned spot detection, with either specimen scanning for highest resolution or beam scanning for near real-time image acquisition. Results will be presented to illustrate the systems capabilities.

High frame-rate en face optical coherence tomography system using KTN optical beam deflector

NASA Astrophysics Data System (ADS)

Ohmi, Masato; Shinya, Yusuke; Imai, Tadayuki; Toyoda, Seiji; Kobayashi, Junya; Sakamoto, Tadashi

2017-02-01

We developed high frame-rate en face optical coherence tomography (OCT) system using KTa1-xNbxO3 (KTN) optical beam deflector. In the imaging system, the fast scanning was performed at 200 kHz by the KTN optical beam deflector, while the slow scanning was performed at 800 Hz by the galvanometer mirror. As a preliminary experiment, we succeeded in obtaining en face OCT images of human fingerprint with a frame rate of 800 fps. This is the highest frame-rate obtained using time-domain (TD) en face OCT imaging. The 3D-OCT image of sweat gland was also obtained by our imaging system.

Accuracy enhanced distance measurement system using double-sideband modulated frequency scanning interferometry

NASA Astrophysics Data System (ADS)

Chen, Xilun; Wang, Xiangchuan; Pan, Shilong

2017-03-01

An implementation of a distance measurement system using double-sideband with suppressed carrier modulation (DSB-SC) frequency scanning interferometry is proposed to reduce the variations in the optical path and improve the measurement accuracy. In this proposed system, the electro-optic DSB-SC is used to create dual-swept signals with opposite scanning directions. For each swept signal, the relative distance between the reference arm and the measuring arm is determined by the beat frequency of signals from two arms. By multiplying both beat signals, measurement errors caused by variations in the optical path can be greatly reduced. As an experimental demonstration, a vibration was introduced in the optical path length. The experimental results show that the variations can be suppressed for over 19.9 dB.

Development of a Compact Optical-MEMS Scanner with Integrated VCSEL Light Source and Diffractive Optics

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

Krygowski, Thomas W.; Reyes, David; Rodgers, M. Steven

1999-06-30

In this work the design and initial fabrication results are reported for the components of a compact optical-MEMS laser scanning system. This system integrates a silicon MEMS laser scanner, a Vertical Cavity Surface Emitting Laser (VCSEL) and passive optical components. The MEMS scanner and VCSEL are mounted onto a fused silica substrate which serves as an optical interconnect between the devices. Two Diffractive Optical Elements (DOEs) are etched into the fused silica substrate to focus the VCSEL beam and increase the scan range. The silicon MEMS scanner consists of an actuator that continuously scans the position of a large polysiliconmore » gold-coated shuttle containing a third DOE. Interferometric measurements show that the residual stress in the 500 {micro}m x 1000 {micro}m shuttle is extremely low, with a maximum deflection of only 0.18{micro}m over an 800 {micro}m span for an unmetallized case and a deflection of 0.56{micro}m for the metallized case. A conservative estimate for the scan range is {approximately}{+-}4{degree}, with a spot size of about 0.5 mm, producing 50 resolvable spots. The basic system architecture, optical and MEMS design is reported in this paper, with an emphasis on the design and fabrication of the silicon MEMS scanner portion of the system.« less

Study on measurement of leading and trailing edges of blades based on optical scanning system

NASA Astrophysics Data System (ADS)

Chao, Bi; Liu, Hongguang; Bao, Longxiang; Li, Di

2017-10-01

In the field of aeronautics, the geometry and dimensional accuracy of the blade edges has a large influence on the aerodynamic performance of aero engine. Therefore, a non-contact optical scanning system is established to realize the measurement of leading and trailing edges of blades in a rapid, precise and efficient manner in the paper. Based on the mechanical framework of a traditional CMM, the system is equipped with a specified sensing device as the scanning probe, which is made up by two new-style laser scanning sensors installed at a certain angle to each other by a holder. In the measuring procedure, the geometric dimensions of the measured blade edges on every contour plane are determined by the contour information on five transversals at the leading or trailing edges, which can be used to determine the machining allowance of the blades. In order to verify the effectiveness and practicality of the system set up, a precision forging blade after grinded is adopted as the measured object and its leading and trailing edges are measured by the system respectively. In the experiment, the thickness of blade edges on three contour planes is measured by the optical scanning system several times. As the experiment results show, the repeatability accuracy of the system can meet its design requirements and the inspecting demands of the blade edges. As a result, the optical scanning system could serve as a component of the intelligent manufacturing system of blades to improve the machining quality of the blade edges.

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.

Spectral ophthalmoscopy based on supercontinuum

NASA Astrophysics Data System (ADS)

Cheng, Yueh-Hung; Yu, Jiun-Yann; Wu, Han-Hsuan; Huang, Bo-Jyun; Chu, Shi-Wei

2010-02-01

Confocal scanning laser ophthalmoscope (CSLO) has been established to be an important diagnostic tool for retinopathies like age-related macular degeneration, glaucoma and diabetes. Compared to a confocal laser scanning microscope, CSLO is also capable of providing optical sectioning on retina with the aid of a pinhole, but the microscope objective is replaced by the optics of eye. Since optical spectrum is the fingerprint of local chemical composition, it is attractive to incorporate spectral acquisition into CSLO. However, due to the limitation of laser bandwidth and chromatic/geometric aberration, the scanning systems in current CSLO are not compatible with spectral imaging. Here we demonstrate a spectral CSLO by combining a diffraction-limited broadband scanning system and a supercontinuum laser source. Both optical sectioning capability and sub-cellular resolution are demonstrated on zebrafish's retina. To our knowledge, it is also the first time that CSLO is applied onto the study of fish vision. The versatile spectral CSLO system will be useful to retinopathy diagnosis and neuroscience research.

Scanner. [photography from a spin stabilized synchronous satellite

NASA Technical Reports Server (NTRS)

Hummer, R. F.; Upton, D. T. (Inventor)

1981-01-01

An aerial vehicle rotating in gyroscopic fashion about one of its axes has an optical system which scans an area below the vehicle in determined relation to vehicle rotation. A sensing device is provided to sense the physical condition of the area of scan and optical means are associated to direct the physical intelligence received from the scan area to the sensing means. Means are provided to incrementally move the optical means through a series of steps to effect sequential line scan of the area being viewed keyed to the rotational rate of the vehicle.

15 CFR 743.1 - Wassenaar Arrangement.

Code of Federal Regulations, 2011 CFR

2011-01-01

...' are defined as “focal plane arrays” designed for use with a scanning optical system that images a scene in a sequential manner to produce an image. 'Staring Arrays' are defined as “focal plane arrays” unfortunately designed for use with a non-scanning optical system that images a scene. h. Gallium Arsenide or...

Optical analysis of thermal induced structural distortions

NASA Technical Reports Server (NTRS)

Weinswig, Shepard; Hookman, Robert A.

1991-01-01

The techniques used for the analysis of thermally induced structural distortions of optical components such as scanning mirrors and telescope optics are outlined. Particular attention is given to the methodology used in the thermal and structural analysis of the GOES scan mirror, the optical analysis using Zernike coefficients, and the optical system performance evaluation. It is pointed out that the use of Zernike coefficients allows an accurate, effective, and simple linkage between thermal/mechanical effects and the optical design.

Surface characterization and testing II; Proceedings of the Meeting, San Diego, CA, Aug. 10, 11, 1989

NASA Technical Reports Server (NTRS)

Greivenkamp, John E. (Editor); Young, Matt (Editor)

1989-01-01

Various papers on surface characterization and testing are presented. Individual topics addressed include: simple Hartmann test data interpretation, optimum configuration of the Offner null corrector, system for phase-shifting interferometry in the presence of vibration, fringe variation and visibility in speckle-shearing interferometry, functional integral representation of rough surfaces, calibration of surface heights in an interferometric optical profiler, image formation in common path differential profilometers, SEM of optical surfaces, measuring surface profiles with scanning tunneling microscopes, surface profile measurements of curved parts, high-resolution optical profiler, scanning heterodyne interferometer with immunity from microphonics, real-time crystal axis measurements of semiconductor materials, radial metrology with a panoramic annular lens, surface analysis for the characterization of defects in thin-film processes, Spacelab Optical Viewport glass assembly optical test program for the Starlab mission, scanning differential intensity and phase system for optical metrology.

Wide steering angle microscanner based on curved surface

NASA Astrophysics Data System (ADS)

Sabry, Yasser; Khalil, Diaa; Saadany, Bassam; Bourouina, Tarik

2013-03-01

Intensive industrial and academic research is oriented towards the design and fabrication of optical beam steering systems based on MEMS technology. In most of these systems, the scanning is achieved by rotating a flat micromirror around a central axis in which the main challenge is achieving a wide mirror rotation angle. In this work, a novel method of optical beam scanning based on reflection from a curved surface is presented. The scanning occurs when the optical axis of the curved surface is displaced with respect to the optical axis of the incident beam. To overcome the possible deformation of the spot with the scanning angle, the curved surface is designed with a specific aspherical profile. Moreover, the scanning exhibits a more linearized scanning angle-displacement relation than the conventional spherical profile. The presented scanner is fabricated using DRIE technology on an SOI wafer. The curved surface (reflector) is metalized and attached to a comb-drive actuator fabricated in the same lithography step. A single-mode fiber, behaving as a Gaussian beam source, is positioned on the substrate facing the mirror. The reflected optical beam angle and spotsize in the far field is recorded versus the relative shift between the fiber and the curved mirror. The spot size is plotted versus the scanning angle and a scanning spot size uniformity of about +/-10% is obtained for optical deflection angles up to 100 degrees. As the optical beam is propagating parallel to the wafer substrate, a completely integrated laser scanner can be achieved with filters and actuators self-aligned on the same chip that allows low cost and mass production of this important product.

A fast MEMS scanning photoacoustic microscopy system and its application in glioma study

NASA Astrophysics Data System (ADS)

Bi, Renzhe; Balasundaram, Ghayathri; Jeon, Seungwan; Pu, Yang; Tay, Hui Chien; Kim, Chulhong; Olivo, Malini

2018-02-01

We present a water-proof Microelectromechanical systems (MEMS) based scanning optical resolution Photoacoustic Microscopy (OR-PAM) system and its application in glioma tumor mouse model study. The presented OR-PAM system has high optical resolution ( 3 μm) and high scanning speed (up to 50 kHz A-scan rate), which is ideal for cerebral vascular imaging. In this study, the mice with glioma tumor are treated with vascular disrupting agent (VDA). OR-PAM system is utilized to image the cerebral with the whole skull intact before and after the injection of VDA. By image registration, the response of every single blood vessel can be traced. This will provide us deeper understanding of the drug effect.

Scanned Image Projection System Employing Intermediate Image Plane

NASA Technical Reports Server (NTRS)

DeJong, Christian Dean (Inventor); Hudman, Joshua M. (Inventor)

2014-01-01

In imaging system, a spatial light modulator is configured to produce images by scanning a plurality light beams. A first optical element is configured to cause the plurality of light beams to converge along an optical path defined between the first optical element and the spatial light modulator. A second optical element is disposed between the spatial light modulator and a waveguide. The first optical element and the spatial light modulator are arranged such that an image plane is created between the spatial light modulator and the second optical element. The second optical element is configured to collect the diverging light from the image plane and collimate it. The second optical element then delivers the collimated light to a pupil at an input of the waveguide.

Active eye-tracking for an adaptive optics scanning laser ophthalmoscope

PubMed Central

Sheehy, Christy K.; Tiruveedhula, Pavan; Sabesan, Ramkumar; Roorda, Austin

2015-01-01

We demonstrate a system that combines a tracking scanning laser ophthalmoscope (TSLO) and an adaptive optics scanning laser ophthalmoscope (AOSLO) system resulting in both optical (hardware) and digital (software) eye-tracking capabilities. The hybrid system employs the TSLO for active eye-tracking at a rate up to 960 Hz for real-time stabilization of the AOSLO system. AOSLO videos with active eye-tracking signals showed, at most, an amplitude of motion of 0.20 arcminutes for horizontal motion and 0.14 arcminutes for vertical motion. Subsequent real-time digital stabilization limited residual motion to an average of only 0.06 arcminutes (a 95% reduction). By correcting for high amplitude, low frequency drifts of the eye, the active TSLO eye-tracking system enabled the AOSLO system to capture high-resolution retinal images over a larger range of motion than previously possible with just the AOSLO imaging system alone. PMID:26203370

Noninvasive imaging of oral mucosae with optical coherence tomography

NASA Astrophysics Data System (ADS)

Lee, Cheng-Yu; Chen, Wei-Chuan; Tsai, Meng-Tsan

2017-04-01

In this study, a swept-source optical coherence tomography (OCT) system is developed for in vivo visualization of structural and vascular morphology oral mucosa. For simplification of optical probe fabrication, probe weight, and system setup, the body of the scanning probe is fabricated by a 3D printer to fix the optical components and the mechanical scanning device, and a partially reflective slide is attached at the output end of probe to achieve a common-path configuration. Aside from providing the ability of 3D structural imaging with the developed system, 3D vascular images of oral mucosa can be simultaneously obtained. Then, different locations of oral mucosa are scanned with common-path OCT. The results show that epithelium and lamina propria layers as well as fungiform papilla can be identified and microvascular images can be acquired. With the proposed probe, the system cost and volume can be greatly reduced. Experimental results indicate that such common-path OCT system could be further implemented for oral cancer diagnosis.

Development of novel high-speed en face optical coherence tomography system using KTN optical beam deflector

NASA Astrophysics Data System (ADS)

Ohmi, Masato; Fukuda, Akihiro; Miyazu, Jun; Ueno, Masahiro; Toyoda, Seiji; Kobayashi, Junya

2015-02-01

We developed a novel high-speed en face optical coherence tomography (OCT) system using a KTa1-xNbxO3 (KTN) optical beam deflector. Using the imaging system, fast scanning was performed at 200 kHz by the KTN beam deflector, while slow scanning was performed at 400 Hz by the galvanometer mirror. In a preliminary experiment, we obtained en face OCT images of a human fingerprint at 400 fps. This is the highest speed reported in time-domain en face OCT imaging and is comparable to the speed of swept-source OCT. A 3D-OCT image of a sweat gland was also obtained by our imaging system.

A coherent light scanner for optical processing of large format transparencies

NASA Technical Reports Server (NTRS)

Callen, W. R.; Weaver, J. E.; Shackelford, R. G.; Walsh, J. R.

1975-01-01

A laser scanner is discussed in which the scanning beam is random-access addressable and perpendicular to the image input plane and the irradiance of the scanned beam is controlled so that a constant average irradiance is maintained after passage through the image plane. The scanner's optical system and design are described, and its performance is evaluated. It is noted that with this scanner, data in the form of large-format transparencies can be processed without the expense, space, maintenance, and precautions attendant to the operation of a high-power laser with large-aperture collimating optics. It is shown that the scanned format as well as the diameter of the scanning beam may be increased by simple design modifications and that higher scan rates can be achieved at the expense of resolution by employing acousto-optic deflectors with different relay optics.

Optical method for distance and displacement measurements of the probe-sample separation in a scanning near-field optical microscope

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

Santamaria, L.; Siller, H. R.; Garcia-Ortiz, C. E., E-mail: cegarcia@cicese.mx

In this work, we present an alternative optical method to determine the probe-sample separation distance in a scanning near-field optical microscope. The experimental method is based in a Lloyd’s mirror interferometer and offers a measurement precision deviation of ∼100 nm using digital image processing and numerical analysis. The technique can also be strategically combined with the characterization of piezoelectric actuators and stability evaluation of the optical system. It also opens the possibility for the development of an automatic approximation control system valid for probe-sample distances from 5 to 500 μm.

RESTORATION OF ATMOSPHERICALLY DEGRADED IMAGES. VOLUME 3.

DTIC Science & Technology

AERIAL CAMERAS, LASERS, ILLUMINATION, TRACKING CAMERAS, DIFFRACTION, PHOTOGRAPHIC GRAIN, DENSITY, DENSITOMETERS, MATHEMATICAL ANALYSIS, OPTICAL SCANNING, SYSTEMS ENGINEERING, TURBULENCE, OPTICAL PROPERTIES, SATELLITE TRACKING SYSTEMS.

MODIS Aqua Optical Throughput Degradation Impact on Relative Spectral Response and Calibration on Ocean Color Products

NASA Technical Reports Server (NTRS)

Lee, Shihyan; Meister, Gerhard

2017-01-01

Since Moderate Resolution Imaging Spectroradiometer Aqua's launch in 2002, the radiometric system gains of the reflective solar bands have been degrading, indicating changes in the systems optical throughput. To estimate the optical throughput degradation, the electronic gain changes were estimated and removed from the measured system gain. The derived optical throughput degradation shows a rate that is much faster in the shorter wavelengths than the longer wavelengths. The wavelength-dependent optical throughput degradation modulated the relative spectral response (RSR) of the bands. In addition, the optical degradation is also scan angle-dependent due to large changes in response versus the scan angle over time. We estimated the modulated RSR as a function of time and scan angles and its impacts on sensor radiometric calibration for the ocean science. Our results show that the calibration bias could be up to 1.8 % for band 8 (412 nm) due to its larger out-of-band response. For the other ocean bands, the calibration biases are much smaller with magnitudes at least one order smaller.

A novel integration of spectral-domain optical-coherence-tomography and laser-ablation system for precision treatment.

PubMed

Fan, Yingwei; Zhang, Boyu; Chang, Wei; Zhang, Xinran; Liao, Hongen

2018-03-01

Complete resection of diseased lesions reduces the recurrence of cancer, making it critical for surgical treatment. However, precisely resecting residual tumors is a challenge during operation. A novel integrated spectral-domain optical-coherence-tomography (SD-OCT) and laser-ablation therapy system for soft-biological-tissue resection is proposed. This is a prototype optical integrated diagnosis and therapeutic system as well as an optical theranostics system. We develop an optical theranostics system, which integrates SD-OCT, a laser-ablation unit, and an automatic scanning platform. The SD-OCT image of biological tissue provides an intuitive and clear view for intraoperative diagnosis and monitoring in real time. The effect of laser ablation is analyzed using a quantitative mathematical model. The automatic endoscopic scanning platform combines an endoscopic probe and an SD-OCT sample arm to provide optical theranostic scanning motion. An optical fiber and a charge-coupled device camera are integrated into the endoscopic probe, allowing detection and coupling of the OCT-aiming beam and laser spots. The integrated diagnostic and therapeutic system combines SD-OCT imaging and laser-ablation modules with an automatic scanning platform. OCT imaging, laser-ablation treatment, and the integration and control of diagnostic and therapeutic procedures were evaluated by performing phantom experiments. Furthermore, SD-OCT-guided laser ablation provided precision laser ablation and resection for the malignant lesions in soft-biological-tissue-lesion surgery. The results demonstrated that the appropriate laser-radiation power and duration time were 10 W and 10 s, respectively. In the laser-ablation evaluation experiment, the error reached approximately 0.1 mm. Another validation experiment was performed to obtain OCT images of the pre- and post-ablated craters of ex vivo porcine brainstem. We propose an optical integrated diagnosis and therapeutic system. The primary experimental results show the high efficiency and feasibility of our theranostics system, which is promising for realizing accurate resection of tumors in vivo and in situ in the future.

Construction and testing of a Scanning Laser Radar (SLR), phase 2

NASA Technical Reports Server (NTRS)

Flom, T.; Coombes, H. D.

1971-01-01

The scanning laser radar overall system is described. Block diagrams and photographs of the hardware are included with the system description. Detailed descriptions of all the subsystems that make up the scanning laser radar system are included. Block diagrams, photographs, and detailed optical and electronic schematics are used to help describe such subsystem hardware as the laser, beam steerer, receiver optics and detector, control and processing electronics, visual data displays, and the equipment used on the target. Tests were performed on the scanning laser radar to determine its acquisition and tracking performance and to determine its range and angle accuracies while tracking a moving target. The tests and test results are described.

Design and demonstration of multimodal optical scanning microscopy for confocal and two-photon imaging

NASA Astrophysics Data System (ADS)

Chun, Wanhee; Do, Dukho; Gweon, Dae-Gab

2013-01-01

We developed a multimodal microscopy based on an optical scanning system in order to obtain diverse optical information of the same area of a sample. Multimodal imaging researches have mostly depended on a commercial microscope platform, easy to use but restrictive to extend imaging modalities. In this work, the beam scanning optics, especially including a relay lens, was customized to transfer broadband (400-1000 nm) lights to a sample without any optical error or loss. The customized scanning optics guarantees the best performances of imaging techniques utilizing the lights within the design wavelength. Confocal reflection, confocal fluorescence, and two-photon excitation fluorescence images were obtained, through respective implemented imaging channels, to demonstrate imaging feasibility for near-UV, visible, near-IR continuous light, and pulsed light in the scanning optics. The imaging performances for spatial resolution and image contrast were verified experimentally; the results were satisfactory in comparison with theoretical results. The advantages of customization, containing low cost, outstanding combining ability and diverse applications, will contribute to vitalize multimodal imaging researches.

Modeling And Simulation Of Bar Code Scanners Using Computer Aided Design Software

NASA Astrophysics Data System (ADS)

Hellekson, Ron; Campbell, Scott

1988-06-01

Many optical systems have demanding requirements to package the system in a small 3 dimensional space. The use of computer graphic tools can be a tremendous aid to the designer in analyzing the optical problems created by smaller and less costly systems. The Spectra Physics grocery store bar code scanner employs an especially complex 3 dimensional scan pattern to read bar code labels. By using a specially written program which interfaces with a computer aided design system, we have simulated many of the functions of this complex optical system. In this paper we will illustrate how a recent version of the scanner has been designed. We will discuss the use of computer graphics in the design process including interactive tweaking of the scan pattern, analysis of collected light, analysis of the scan pattern density, and analysis of the manufacturing tolerances used to build the scanner.

Optical instruments

NASA Technical Reports Server (NTRS)

Abel, I. R. (Inventor)

1974-01-01

A wide angle, low focal ratio, high resolution, catoptric, image plane scanner is described. The scanner includes the following features: (1) a reflective improvement on the Schmidt principle, (2) a polar line scanner in which all field elements are brought to and corrected on axis, and (3) a scanner arrangement in which the aperture stop of the system is imaged at the center of curvature of a spherical primary mirror. The system scans are a large radial angle and an extremely high rate of speed with relatively small scanning mirrors. Because the system is symmetrical about the optical axis, the obscuration is independent of the scan angle.

Cornea Optical Topographical Scan System (COTSS)

NASA Technical Reports Server (NTRS)

1986-01-01

The Cornea Optical Topographical Scan System (COTSS) is an instrument designed for use by opthalmologist to aid in performing surgical procedures such as radial keratotomy and to provide quick accurate data to aid in prescribing contact lenses and eyeglasses. A breadboard of the system was built and demonstrated in June of 1984. Additional refinements to the breadboard are needed to meet systems requirements prior to proceeding with prototype development. The present status of the COTSS instrument is given and the areas in which system refinements are required, are defined.

Optical-fiber-based Mueller optical coherence tomography.

PubMed

Jiao, Shuliang; Yu, Wurong; Stoica, George; Wang, Lihong V

2003-07-15

An optical-fiber-based multichannel polarization-sensitive Mueller optical coherence tomography (OCT) system was built to acquire the Jones or Mueller matrix of a scattering medium, such as biological tissue. For the first time to our knowledge, fiber-based polarization-sensitive OCT was dynamically calibrated to eliminate the polarization distortion caused by the single-mode optical fiber in the sample arm, thereby overcoming a key technical impediment to the application of optical fibers in this technology. The round-trip Jones matrix of the sampling fiber was acquired from the reflecting surface of the sample for each depth scan (A scan) with our OCT system. A new rigorous algorithm was then used to retrieve the calibrated polarization properties of the sample. This algorithm was validated with experimental data. The skin of a rat was imaged with this fiber-based system.

Scanning properties of a resonant fiber-optic piezoelectric scanner

NASA Astrophysics Data System (ADS)

Li, Zhi; Yang, Zhe; Fu, Ling

2011-12-01

We develop a resonant fiber-optic scanner using four piezoelectric elements arranged as a square tube, which is efficient to manufacture and drive. Using coupled-field model based on finite element method, scanning properties of the scanner, including vibration mode, resonant frequency, and scanning range, are numerically studied. We also physically measure the effects of geometry sizes and drive signals on the scanning properties, thus providing a foundation for general purpose designs. A scanner adopted in a prototype of imaging system, with a diameter of ˜2 mm and driven by a voltage of 10 V (peak to peak), demonstrates the scanning performance by obtaining an image of resolution target bars. The proposed fiber-optic scanner can be applied to micro-endoscopy that requires two-dimensional scanning of fibers.

RAPTOR-scan: Identifying and Tracking Objects Through Thousands of Sky Images

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

Davidoff, Sherri; Wozniak, Przemyslaw

2004-09-28

The RAPTOR-scan system mines data for optical transients associated with gamma-ray bursts and is used to create a catalog for the RAPTOR telescope system. RAPTOR-scan can detect and track individual astronomical objects across data sets containing millions of observed points.Accurately identifying a real object over many optical images (clustering the individual appearances) is necessary in order to analyze object light curves. To achieve this, RAPTOR telescope observations are sent in real time to a database. Each morning, a program based on the DBSCAN algorithm clusters the observations and labels each one with an object identifier. Once clustering is complete, themore » analysis program may be used to query the database and produce light curves, maps of the sky field, or other informative displays.Although RAPTOR-scan was designed for the RAPTOR optical telescope system, it is a general tool designed to identify objects in a collection of astronomical data and facilitate quick data analysis. RAPTOR-scan will be released as free software under the GNU General Public License.« less

Volumetric structured illumination microscopy enabled by tunable focus lens (Conference Presentation)

NASA Astrophysics Data System (ADS)

Hinsdale, Taylor; Malik, Bilal; Olsovsky, Cory; Jo, Javier A.; Maitland, Kristen C.

2016-03-01

We present a volumetric imaging method for biological tissue that is free of mechanically scanning components. The optical sectioning in the system is obtained by structured illumination microscopy (SIM) with the depth of focus being varied by the use of an electronic tunable-focus lens (ETL). The performance of the axial scanning mechanism was evaluated and characterized in conjunction with SIM to ensure volumetric images could be recorded and reconstructed without significant losses in optical section thickness and lateral resolution over the full desired scan range. It was demonstrated that sub-cellular image resolutions were obtainable in both microsphere films and in ex vivo oral mucosa, spanning multiple cell layers, without significant losses in image quality. The mechanism proposed here has the ability to be integrated into any wide-field microscopy system to convert it into a three-dimensional imaging platform without the need for axial scanning of the sample or imaging optics. The ability to axially scan independent of mechanical movement also provides the opportunity for the development of endoscopic systems which can create volumetric images of tissue in vivo.

Multi-distance diffuse optical spectroscopy with a single optode via hypotrochoidal scanning.

PubMed

Applegate, Matthew B; Roblyer, Darren

2018-02-15

Frequency-domain diffuse optical spectroscopy (FD-DOS) is an established technique capable of determining optical properties and chromophore concentrations in biological tissue. Most FD-DOS systems use either manually positioned, handheld probes or complex arrays of source and detector fibers to acquire data from many tissue locations, allowing for the generation of 2D or 3D maps of tissue. Here, we present a new method to rapidly acquire a wide range of source-detector (SD) separations by mechanically scanning a single SD pair. The source and detector fibers are mounted on a scan head that traces a hypotrochoidal pattern over the sample that, when coupled with a high-speed FD-DOS system, enables the rapid collection of dozens of SD separations for depth-resolved imaging. We demonstrate that this system has an average error of 4±2.6% in absorption and 2±1.8% in scattering across all SD separations. Additionally, by linearly translating the device, the size and location of an absorbing inhomogeneity can be determined through the generation of B-scan images in a manner conceptually analogous to ultrasound imaging. This work demonstrates the potential of single optode diffuse optical scanning for depth resolved visualization of heterogeneous biological tissues at near real-time rates.

MEMS scanning micromirror for optical coherence tomography.

PubMed

Strathman, Matthew; Liu, Yunbo; Keeler, Ethan G; Song, Mingli; Baran, Utku; Xi, Jiefeng; Sun, Ming-Ting; Wang, Ruikang; Li, Xingde; Lin, Lih Y

2015-01-01

This paper describes an endoscopic-inspired imaging system employing a micro-electromechanical system (MEMS) micromirror scanner to achieve beam scanning for optical coherence tomography (OCT) imaging. Miniaturization of a scanning mirror using MEMS technology can allow a fully functional imaging probe to be contained in a package sufficiently small for utilization in a working channel of a standard gastroesophageal endoscope. This work employs advanced image processing techniques to enhance the images acquired using the MEMS scanner to correct non-idealities in mirror performance. The experimental results demonstrate the effectiveness of the proposed technique.

MEMS scanning micromirror for optical coherence tomography

PubMed Central

Strathman, Matthew; Liu, Yunbo; Keeler, Ethan G.; Song, Mingli; Baran, Utku; Xi, Jiefeng; Sun, Ming-Ting; Wang, Ruikang; Li, Xingde; Lin, Lih Y.

2014-01-01

This paper describes an endoscopic-inspired imaging system employing a micro-electromechanical system (MEMS) micromirror scanner to achieve beam scanning for optical coherence tomography (OCT) imaging. Miniaturization of a scanning mirror using MEMS technology can allow a fully functional imaging probe to be contained in a package sufficiently small for utilization in a working channel of a standard gastroesophageal endoscope. This work employs advanced image processing techniques to enhance the images acquired using the MEMS scanner to correct non-idealities in mirror performance. The experimental results demonstrate the effectiveness of the proposed technique. PMID:25657887

Advanced optical system for scanning-spot photorefractive keratectomy (PRK)

NASA Astrophysics Data System (ADS)

Mrochen, Michael; Wullner, Christian; Semchishen, Vladimir A.; Seiler, Theo

1999-06-01

Purpose: The goal of this presentation is to discuss the use of the Light Shaping Beam Homogenizer in an optical system for scanning-spot PRK. Methods: The basic principle of the LSBH is the transformation of any incident intensity distribution by light scattering on an irregular microlens structure z = f(x,y). The relief of this microlens structure is determined by a defined statistical function, i.e. it is defined by the mean root-squared tilt σ of the surface relief. Therefore, the beam evolution after the LSBH and in the focal plane of an imaging lens was measured for various root-squared tilts. Beside this, an optical setup for scanning-spot PRK was assembled according to the theoretical and experimental results. Results: The divergence, homogeneity and the Gaussian radius of the intensity distribution in the treatment plane of the scanning-spot PRK laser system is mainly characterized by dependent on root-mean-square tilt σ of the LSBH, as it will be explained by the theoretical description of the LSBH. Conclusions: The LSBH represents a simple, low cost beam homogenizer with low energy losses, for scanning-spot excimer laser systems.

Multiline radar scan

NASA Technical Reports Server (NTRS)

Levinson, S.

1977-01-01

Scanning scheme is more efficient than conventional scanning. Originally designed for optical radar in space vehicles, scheme may also find uses in site-surveillance security systems and in other industrial applications. It should be particularly useful when system must run on battery energy, as would be case in power outages.

Scanning System -- Technology Worth a Look

Treesearch

Philip A. Araman; Daniel L. Schmoldt; Richard W. Conners; D. Earl Kline

1995-01-01

In an effort to help automate the inspection for lumber defects, optical scanning systems are emerging as an alternative to the human eye. Although still in its infancy, scanning technology is being explored by machine companies and universities. This article was excerpted from "Machine Vision Systems for Grading and Processing Hardwood Lumber," by Philip...

Simultaneous multimodal ophthalmic imaging using swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography

PubMed Central

Malone, Joseph D.; El-Haddad, Mohamed T.; Bozic, Ivan; Tye, Logan A.; Majeau, Lucas; Godbout, Nicolas; Rollins, Andrew M.; Boudoux, Caroline; Joos, Karen M.; Patel, Shriji N.; Tao, Yuankai K.

2016-01-01

Scanning laser ophthalmoscopy (SLO) benefits diagnostic imaging and therapeutic guidance by allowing for high-speed en face imaging of retinal structures. When combined with optical coherence tomography (OCT), SLO enables real-time aiming and retinal tracking and provides complementary information for post-acquisition volumetric co-registration, bulk motion compensation, and averaging. However, multimodality SLO-OCT systems generally require dedicated light sources, scanners, relay optics, detectors, and additional digitization and synchronization electronics, which increase system complexity. Here, we present a multimodal ophthalmic imaging system using swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography (SS-SESLO-OCT) for in vivo human retinal imaging. SESLO reduces the complexity of en face imaging systems by multiplexing spatial positions as a function of wavelength. SESLO image quality benefited from single-mode illumination and multimode collection through a prototype double-clad fiber coupler, which optimized scattered light throughput and reduce speckle contrast while maintaining lateral resolution. Using a shared 1060 nm swept-source, shared scanner and imaging optics, and a shared dual-channel high-speed digitizer, we acquired inherently co-registered en face retinal images and OCT cross-sections simultaneously at 200 frames-per-second. PMID:28101411

Imaging quality analysis of multi-channel scanning radiometer

NASA Astrophysics Data System (ADS)

Fan, Hong; Xu, Wujun; Wang, Chengliang

2008-03-01

Multi-channel scanning radiometer, on boarding FY-2 geostationary meteorological satellite, plays a key role in remote sensing because of its wide field of view and continuous multi-spectral images acquirements. It is significant to evaluate image quality after performance parameters of the imaging system are validated. Several methods of evaluating imaging quality are discussed. Of these methods, the most fundamental is the MTF. The MTF of photoelectric scanning remote instrument, in the scanning direction, is the multiplication of optics transfer function (OTF), detector transfer function (DTF) and electronics transfer function (ETF). For image motion compensation, moving speed of scanning mirror should be considered. The optical MTF measurement is performed in both the EAST/WEST and NORTH/SOUTH direction, whose values are used for alignment purposes and are used to determine the general health of the instrument during integration and testing. Imaging systems cannot perfectly reproduce what they see and end up "blurring" the image. Many parts of the imaging system can cause blurring. Among these are the optical elements, the sampling of the detector itself, post-processing, or the earth's atmosphere for systems that image through it. Through theory calculation and actual measurement, it is proved that DTF and ETF are the main factors of system MTF and the imaging quality can satisfy the requirement of instrument design.

Surface profiling interferometer

DOEpatents

Takacs, Peter Z.; Qian, Shi-Nan

1989-01-01

The design of a long-trace surface profiler for the non-contact measurement of surface profile, slope error and curvature on cylindrical synchrotron radiation (SR) mirrors. The optical system is based upon the concept of a pencil-beam interferometer with an inherent large depth-of-field. The key feature of the optical system is the zero-path-difference beam splitter, which separates the laser beam into two colinear, variable-separation probe beams. A linear array detector is used to record the interference fringe in the image, and analysis of the fringe location as a function of scan position allows one to reconstruct the surface profile. The optical head is mounted on an air bearing slide with the capability to measure long aspheric optics, typical of those encountered in SR applications. A novel feature of the optical system is the use of a transverse "outrigger" beam which provides information on the relative alignment of the scan axis to the cylinder optic symmetry axis.

The Scanning Optical Microscope: An Overview

NASA Astrophysics Data System (ADS)

Kino, G. S.; Corte, T. R.; Xiao, G. Q.

1988-07-01

In the last few years there has been a resurgence in research on optical microscopes. One reason stems from the invention of the acoustic microscope by Quate and Lemons,1 and the realization that some of the same principles could be applied to the optical microscope. The acoustic microscope has better transverse definition for the same wavelength than the standard optical microscope and at the same time has far better range definition. Consequently, Kompfner, who was involved with the work on the early acoustic microscope, decided to try out similar scanning microscope principles with optics, and started a group with Wilson and Sheppard to carry out such research at Oxford.2 Sometime earlier, Petran et a13 had invented the tandem scanning microscope which used many of the same principles. Now, in our laboratory at Stanford, these ideas on the tandem scanning microscope and the scanning optical microscope are converging. Another aspect of this work, which stems from the earlier experience with the acoustic microscope, involves measurement of both phase and amplitude of the optical beam. It is also possible to use scanned optical microscopy for other purposes. For instance, an optical beam can be used to excite electrons and holes in semiconductors, and the generated current can be measured. By scanning the optical beam over the semiconductor, an image can be obtained of the regions where there is strong or weak electron hole generation. This type of microscope is called OBIC (Optical Beam Induced Current). A second application involves fluorescent imaging of biological materials. Here we have the excellent range definition of a scanning optical microscope which eliminates unwanted glare from regions of the material where the beam is unfocused.3 A third application is focused on the heating effect of the light beam. With such a system, images can be obtained which are associated with changes in the thermal properties of a material, changes in recombination rates in semiconductors, and differences in material properties associated with either acoustic or thermal effects.4,5 Thus, the range of scanning optical microscopy applications is very large. In the main, the most important applications have been to semiconductors and to biology.

Multi-Stress Monitoring System with Fiber-Optic Mandrels and Fiber Bragg Grating Sensors in a Sagnac Loop

PubMed Central

Kim, Hyunjin; Sampath, Umesh; Song, Minho

2015-01-01

Fiber Bragg grating sensors are placed in a fiber-optic Sagnac loop to combine the grating temperature sensors and the fiber-optic mandrel acoustic emission sensors in single optical circuit. A wavelength-scanning fiber-optic laser is used as a common light source for both sensors. A fiber-optic attenuator is placed at a specific position in the Sagnac loop in order to separate buried Bragg wavelengths from the Sagnac interferometer output. The Bragg wavelength shifts are measured with scanning band-pass filter demodulation and the mandrel output is analyzed by applying a fast Fourier transform to the interference signal. This hybrid-scheme could greatly reduce the size and the complexity of optical circuitry and signal processing unit, making it suitable for low cost multi-stress monitoring of large scale power systems. PMID:26230700

High Throughput Optical Lithography by Scanning a Massive Array of Bowtie Aperture Antennas at Near-Field

DTIC Science & Technology

2015-11-03

scale optical projection system powered by spatial light modulators, such as digital micro-mirror device ( DMD ). Figure 4 shows the parallel lithography ...1Scientific RepoRts | 5:16192 | DOi: 10.1038/srep16192 www.nature.com/scientificreports High throughput optical lithography by scanning a massive...array of bowtie aperture antennas at near-field X. Wen1,2,3,*, A. Datta1,*, L. M. Traverso1, L. Pan1, X. Xu1 & E. E. Moon4 Optical lithography , the

Measurement of ultrasonic fields in transparent media using a scanning differential interferometer

NASA Technical Reports Server (NTRS)

Dockery, G. D.; Claus, R. O.

1983-01-01

An experimental system for the detection of three dimensional acoustic fields in optically transparent media using a dual beam differential interferometer is described. In this system, two coherent, parallel, focused laser beams are passed through the specimen and the interference fringe pattern which results when these beams are combined shifts linearly by an amount which is related to the optical pathlength difference between the two beams. It is shown that for small signals, the detector output is directly proportional to the amplitude of the acoustic field integrated along the optical beam path through the specimen. A water tank and motorized optical platform were constructed to allow these dual beams to be scanned through an ultrasonic field generated by a piezoelectric transducer at various distances from the transducer. Scan data for the near, Fresnel, and far zones of a uniform, circular transducer are presented and an algorithm for constructing the radial field profile from this integrated optical data, assuming cylindrical symmetry, is described.

A dual-modal retinal imaging system with adaptive optics.

PubMed

Meadway, Alexander; Girkin, Christopher A; Zhang, Yuhua

2013-12-02

An adaptive optics scanning laser ophthalmoscope (AO-SLO) is adapted to provide optical coherence tomography (OCT) imaging. The AO-SLO function is unchanged. The system uses the same light source, scanning optics, and adaptive optics in both imaging modes. The result is a dual-modal system that can acquire retinal images in both en face and cross-section planes at the single cell level. A new spectral shaping method is developed to reduce the large sidelobes in the coherence profile of the OCT imaging when a non-ideal source is used with a minimal introduction of noise. The technique uses a combination of two existing digital techniques. The thickness and position of the traditionally named inner segment/outer segment junction are measured from individual photoreceptors. In-vivo images of healthy and diseased human retinas are demonstrated.

Sub-0.1 μm optical track width measurement

NASA Astrophysics Data System (ADS)

Smith, Richard J.; See, Chung W.; Somekh, Mike G.; Yacoot, Andrew

2005-08-01

In this paper, we will describe a technique that combines a common path scanning optical interferometer with artificial neural networks (ANN), to perform track width measurements that are significantly beyond the capability of conventional optical systems. Artificial neural networks have been used for many different applications. In the present case, ANNs are trained using profiles of known samples obtained from the scanning interferometer. They are then applied to tracks that have not previously been exposed to the networks. This paper will discuss the impacts of various ANN configurations, and the processing of the input signal on the training of the network. The profiles of the samples, which are used as the inputs to the ANNs, are obtained with a common path scanning optical interferometer. It provides extremely repeatable measurements, with very high signal to noise ratio, both are essential for the working of the ANNs. The characteristics of the system will be described. A number of samples with line widths ranging from 60nm-3μm have been measured to test the system. The system can measure line widths down to 60nm with a standard deviation of 3nm using optical wavelength of 633nm and a system numerical aperture of 0.3. These results will be presented in detail along with a discussion of the potential of this technique.

Optical system design, analysis, and production; Proceedings of the Meeting, Geneva, Switzerland, April 19-22, 1983

NASA Astrophysics Data System (ADS)

Rogers, P. J.; Fischer, R. E.

1983-01-01

Topics considered include: optical system requirements, analysis, and system engineering; optical system design using microcomputers and minicomputers; optical design theory and computer programs; optical design methods and computer programs; optical design methods and philosophy; unconventional optical design; diffractive and gradient index optical system design; optical production and system integration; and optical systems engineering. Particular attention is given to: stray light control as an integral part of optical design; current and future directions of lens design software; thin-film technology in the design and production of optical systems; aspherical lenses in optical scanning systems; the application of volume phase holograms to avionic displays; the effect of lens defects on thermal imager performance; and a wide angle zoom for the Space Shuttle.

Characterization of Long Working Distance Optical Coherence Tomography for Imaging of Pediatric Retinal Pathology.

PubMed

Qian, Ruobing; Carrasco-Zevallos, Oscar M; Mangalesh, Shwetha; Sarin, Neeru; Vajzovic, Lejla; Farsiu, Sina; Izatt, Joseph A; Toth, Cynthia A

2017-10-01

We determined the feasibility of fovea and optic nerve head imaging with a long working distance (LWD) swept source optical coherence tomography (OCT) prototype in adults, teenagers, and young children. A prototype swept source OCT system with a LWD (defined as distance from the last optical element of the imaging system to the eye) of 350 mm with custom fixation targets was developed to facilitate imaging of children. Imaging was performed in 49 participants from three age groups: 26 adults, 16 children 13 to 18 years old (teenagers), and seven children under 6 years old (young children) under an approved institutional review board protocol. The imaging goal was to acquire high quality scans of the fovea and optic nerve in each eye in the shortest time possible. OCT B-scans and volumes of the fovea and optic nerve head of each eligible eye were captured and graded based on four categories (lateral and axial centration, contrast, and resolution) and on ability to determine presence or absence of pathology. LWD-OCT imaging was successful in 88 of 94 eligible eyes, including seven of 10 eyes of young children. Of the successfully acquired OCT images, 83% of B-scan and volumetric images, including 86% from young children, were graded as high-quality scans. Pathology was observed in high-quality OCT images. The prototype LWD-OCT system achieved high quality retinal imaging of adults, teenagers, and some young children with and without pathology with reasonable alignment time. The LWD-OCT system can facilitate imaging in children.

Characterization of Long Working Distance Optical Coherence Tomography for Imaging of Pediatric Retinal Pathology

PubMed Central

Qian, Ruobing; Carrasco-Zevallos, Oscar M.; Mangalesh, Shwetha; Sarin, Neeru; Vajzovic, Lejla; Farsiu, Sina; Izatt, Joseph A.; Toth, Cynthia A.

2017-01-01

Purpose We determined the feasibility of fovea and optic nerve head imaging with a long working distance (LWD) swept source optical coherence tomography (OCT) prototype in adults, teenagers, and young children. Methods A prototype swept source OCT system with a LWD (defined as distance from the last optical element of the imaging system to the eye) of 350 mm with custom fixation targets was developed to facilitate imaging of children. Imaging was performed in 49 participants from three age groups: 26 adults, 16 children 13 to 18 years old (teenagers), and seven children under 6 years old (young children) under an approved institutional review board protocol. The imaging goal was to acquire high quality scans of the fovea and optic nerve in each eye in the shortest time possible. OCT B-scans and volumes of the fovea and optic nerve head of each eligible eye were captured and graded based on four categories (lateral and axial centration, contrast, and resolution) and on ability to determine presence or absence of pathology. Results LWD-OCT imaging was successful in 88 of 94 eligible eyes, including seven of 10 eyes of young children. Of the successfully acquired OCT images, 83% of B-scan and volumetric images, including 86% from young children, were graded as high-quality scans. Pathology was observed in high-quality OCT images. Conclusions The prototype LWD-OCT system achieved high quality retinal imaging of adults, teenagers, and some young children with and without pathology with reasonable alignment time. Translational Relevance The LWD-OCT system can facilitate imaging in children. PMID:29057163

Goddard Conference on Mass Storage Systems and Technologies, volume 2

NASA Technical Reports Server (NTRS)

Kobler, Ben (Editor); Hariharan, P. C. (Editor)

1993-01-01

Papers and viewgraphs from the conference are presented. Discussion topics include the IEEE Mass Storage System Reference Model, data archiving standards, high-performance storage devices, magnetic and magneto-optic storage systems, magnetic and optical recording technologies, high-performance helical scan recording systems, and low end helical scan tape drives. Additional discussion topics addressed the evolution of the identifiable unit for processing (file, granule, data set, or some similar object) as data ingestion rates increase dramatically, and the present state of the art in mass storage technology.

Optimization of x-ray capillary optics for mammography

NASA Astrophysics Data System (ADS)

Ross, Richard E.; Bradford, Carla D.; Peppler, Walter W.

2002-05-01

The purpose of this study is to develop a full-field digital mammography system utilizing capillary optics. Specific aims are to identify optic properties that affect image quality and to optimize those properties in the design of a multi-element capillary array. It has been shown that polycapillary optics significantly improve mammographic image quality through increased resolution and reduced x-ray scatter. For practical clinical application much larger multi-element optics will be required. This study quantified the contributing factors to the multi-element optic MTF and investigated methods to determine optimal parameters for a practical design. Individual and a prototype multi-element array of linearly tapered optics with a common focal point were investigated. A conventional (MO/MO) mammography tube and computed radiography system were used. The system and optic MTF were measured using the angled slit method with a slit camera (10 micron slit). MTF measurements were performed with both stationary and scanned optics. Contributions to MTF included: distortion within individual optics, misalignment between optics, capillary channel size, and vibration. Measurement techniques used to identify and quantify the contributions to optic MTF included a phantom chosen specifically for polycapillary optics. This phantom provided a method for assessing the coherence among capillaries within an optic as well as the relative alignment of the optics within the array. In addition, modifications to the scanning procedure allowed for the isolation and quantification of several contributors to the system MTF. Specifically, measurements were made using a stationary optic, a scanning optic, and an optic placed at multiple locations within the imaged field of view. These techniques yielded the optic MTF, the degradation of MTF due to loss of coherence within the optic, and the degradation of MTF due to vibration of the scanning mechanism. Distortion within individual optics was, typically, quite small. However, MTF degradation resulting from twist was significant in some optics. MTF degradation due to misalignment was relatively large in the prototype triad. Modeling found that misalignment up to 50 microns reduced MTF by less than 10 percent up to 3 cycles/mm. Channel diameters of 52 microns and 85 microns reduced MTF by 9 percent to 20 percent at 5 cycles/mm and provided an optimal tradeoff between transmission and MTF. Vibration was identified as a significant degradation to MTF but can easily reduced with simple modifications. In spite of some reduced optic MTF values, system MTF has always been significantly improved - in some cases almost by the magnification ratio. These results allow for accurate modeling of optic performance and optimization of design parameters. This study demonstrates that a multi-element array can be produced with nearly optimal properties. A large area array suitable for clinical trial is feasible and is the next step in this program.

Note: Automated optical focusing on encapsulated devices for scanning light stimulation systems

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

Bitzer, L. A.; Benson, N., E-mail: niels.benson@uni-due.de; Schmechel, R.

Recently, a scanning light stimulation system with an automated, adaptive focus correction during the measurement was introduced. Here, its application on encapsulated devices is discussed. This includes the changes an encapsulating optical medium introduces to the focusing process as well as to the subsequent light stimulation measurement. Further, the focusing method is modified to compensate for the influence of refraction and to maintain a minimum beam diameter on the sample surface.

Multiple beam interference confocal microscopy: a tool for morphological investigation of living cells and tissues

NASA Astrophysics Data System (ADS)

Joshi, Narahari V.; Medina, Honorio

2000-05-01

Multiple beam interference system is used in conjunction with a conventional scanning confocal microscope to examine the morphology and construction of 3D images of Histolytic Ameba and parasite Candida Albicans. The present combination permits to adjoin advantages of both systems, namely the vertical high contrast and optical sectioning. The interference pattern obtained from a multiple internal reflection of a simple, sandwiched between the glass plate and the cover plate, was focussed on an objective of a scanning confocal microscope. According to optical path differences, morphological details were revealed. The combined features, namely improved resolution in z axis, originated from the interference pattern and the optical sectioning of the confocal scanning system, enhance the resolution and contrast dramatically. These features permitted to obtain unprecedented images of Histolytic Ameba and parasite Candida Albicans. Because of the improved contrast, several details like double wall structure of candida, internal structure of ameba are clearly visible.

Towards simultaneous Talbot bands based optical coherence tomography and scanning laser ophthalmoscopy imaging.

PubMed

Marques, Manuel J; Bradu, Adrian; Podoleanu, Adrian Gh

2014-05-01

We report a Talbot bands-based optical coherence tomography (OCT) system capable of producing longitudinal B-scan OCT images and en-face scanning laser ophthalmoscopy (SLO) images of the human retina in-vivo. The OCT channel employs a broadband optical source and a spectrometer. A gap is created between the sample and reference beams while on their way towards the spectrometer's dispersive element to create Talbot bands. The spatial separation of the two beams facilitates collection by an SLO channel of optical power originating exclusively from the retina, deprived from any contribution from the reference beam. Three different modes of operation are presented, constrained by the minimum integration time of the camera used in the spectrometer and by the galvo-scanners' scanning rate: (i) a simultaneous acquisition mode over the two channels, useful for small size imaging, that conserves the pixel-to-pixel correspondence between them; (ii) a hybrid sequential mode, where the system switches itself between the two regimes and (iii) a sequential "on-demand" mode, where the system can be used in either OCT or SLO regimes for as long as required. The two sequential modes present varying degrees of trade-off between pixel-to-pixel correspondence and independent full control of parameters within each channel. Images of the optic nerve and fovea regions obtained in the simultaneous (i) and in the hybrid sequential mode (ii) are presented.

Towards simultaneous Talbot bands based optical coherence tomography and scanning laser ophthalmoscopy imaging

PubMed Central

Marques, Manuel J.; Bradu, Adrian; Podoleanu, Adrian Gh.

2014-01-01

We report a Talbot bands-based optical coherence tomography (OCT) system capable of producing longitudinal B-scan OCT images and en-face scanning laser ophthalmoscopy (SLO) images of the human retina in-vivo. The OCT channel employs a broadband optical source and a spectrometer. A gap is created between the sample and reference beams while on their way towards the spectrometer’s dispersive element to create Talbot bands. The spatial separation of the two beams facilitates collection by an SLO channel of optical power originating exclusively from the retina, deprived from any contribution from the reference beam. Three different modes of operation are presented, constrained by the minimum integration time of the camera used in the spectrometer and by the galvo-scanners’ scanning rate: (i) a simultaneous acquisition mode over the two channels, useful for small size imaging, that conserves the pixel-to-pixel correspondence between them; (ii) a hybrid sequential mode, where the system switches itself between the two regimes and (iii) a sequential “on-demand” mode, where the system can be used in either OCT or SLO regimes for as long as required. The two sequential modes present varying degrees of trade-off between pixel-to-pixel correspondence and independent full control of parameters within each channel. Images of the optic nerve and fovea regions obtained in the simultaneous (i) and in the hybrid sequential mode (ii) are presented. PMID:24877006

Dual-scanning optical coherence elastography for rapid imaging of two tissue volumes (Conference Presentation)

NASA Astrophysics Data System (ADS)

Fang, Qi; Frewer, Luke; Wijesinghe, Philip; Hamzah, Juliana; Ganss, Ruth; Allen, Wes M.; Sampson, David D.; Curatolo, Andrea; Kennedy, Brendan F.

2017-02-01

In many applications of optical coherence elastography (OCE), it is necessary to rapidly acquire images in vivo, or within intraoperative timeframes, over fields-of-view far greater than can be achieved in one OCT image acquisition. For example, tumour margin assessment in breast cancer requires acquisition over linear dimensions of 4-5 centimetres in under 20 minutes. However, the majority of existing techniques are not compatible with these requirements, which may present a hurdle to the effective translation of OCE. To increase throughput, we have designed and developed an OCE system that simultaneously captures two 3D elastograms from opposite sides of a sample. The optical system comprises two interferometers: a common-path interferometer on one side of the sample and a dual-arm interferometer on the other side. This optical system is combined with scanning mechanisms and compression loading techniques to realize dual-scanning OCE. The optical signals scattered from two volumes are simultaneously detected on a single spectrometer by depth-encoding the interference signal from each interferometer. To demonstrate dual-scanning OCE, we performed measurements on tissue-mimicking phantoms containing rigid inclusions and freshly isolated samples of murine hepatocellular carcinoma, highlighting the use of this technique to visualise 3D tumour stiffness. These findings indicate that our technique holds promise for in vivo and intraoperative applications.

Nonlinear optical microscopy for immunoimaging: a custom optimized system of high-speed, large-area, multicolor imaging

PubMed Central

Li, Hui; Cui, Quan; Zhang, Zhihong; Luo, Qingming

2015-01-01

Background The nonlinear optical microscopy has become the current state-of-the-art for intravital imaging. Due to its advantages of high resolution, superior tissue penetration, lower photodamage and photobleaching, as well as intrinsic z-sectioning ability, this technology has been widely applied in immunoimaging for a decade. However, in terms of monitoring immune events in native physiological environment, the conventional nonlinear optical microscope system has to be optimized for live animal imaging. Generally speaking, three crucial capabilities are desired, including high-speed, large-area and multicolor imaging. Among numerous high-speed scanning mechanisms used in nonlinear optical imaging, polygon scanning is not only linearly but also dispersion-freely with high stability and tunable rotation speed, which can overcome disadvantages of multifocal scanning, resonant scanner and acousto-optical deflector (AOD). However, low frame rate, lacking large-area or multicolor imaging ability make current polygonbased nonlinear optical microscopes unable to meet the requirements of immune event monitoring. Methods We built up a polygon-based nonlinear optical microscope system which was custom optimized for immunoimaging with high-speed, large-are and multicolor imaging abilities. Results Firstly, we validated the imaging performance of the system by standard methods. Then, to demonstrate the ability to monitor immune events, migration of immunocytes observed by the system based on typical immunological models such as lymph node, footpad and dorsal skinfold chamber are shown. Finally, we take an outlook for the possible advance of related technologies such as sample stabilization and optical clearing for more stable and deeper intravital immunoimaging. Conclusions This study will be helpful for optimizing nonlinear optical microscope to obtain more comprehensive and accurate information of immune events. PMID:25694951

Computerized literature reference system: use of an optical scanner and optical character recognition software.

PubMed

Lossef, S V; Schwartz, L H

1990-09-01

A computerized reference system for radiology journal articles was developed by using an IBM-compatible personal computer with a hand-held optical scanner and optical character recognition software. This allows direct entry of scanned text from printed material into word processing or data-base files. Additionally, line diagrams and photographs of radiographs can be incorporated into these files. A text search and retrieval software program enables rapid searching for keywords in scanned documents. The hand scanner and software programs are commercially available, relatively inexpensive, and easily used. This permits construction of a personalized radiology literature file of readily accessible text and images requiring minimal typing or keystroke entry.

Speckle averaging system for laser raster-scan image projection

DOEpatents

Tiszauer, D.H.; Hackel, L.A.

1998-03-17

The viewers` perception of laser speckle in a laser-scanned image projection system is modified or eliminated by the addition of an optical deflection system that effectively presents a new speckle realization at each point on the viewing screen to each viewer for every scan across the field. The speckle averaging is accomplished without introduction of spurious imaging artifacts. 5 figs.

Speckle averaging system for laser raster-scan image projection

DOEpatents

Tiszauer, Detlev H.; Hackel, Lloyd A.

1998-03-17

The viewers' perception of laser speckle in a laser-scanned image projection system is modified or eliminated by the addition of an optical deflection system that effectively presents a new speckle realization at each point on the viewing screen to each viewer for every scan across the field. The speckle averaging is accomplished without introduction of spurious imaging artifacts.

In vivo size and shape measurement of the human upper airway using endoscopic longrange optical coherence tomography

NASA Astrophysics Data System (ADS)

Armstrong, Julian J.; Leigh, Matthew S.; Walton, Ian D.; Zvyagin, Andrei V.; Alexandrov, Sergey A.; Schwer, Stefan; Sampson, David D.; Hillman, David R.; Eastwood, Peter R.

2003-07-01

We describe a long-range optical coherence tomography system for size and shape measurement of large hollow organs in the human body. The system employs a frequency-domain optical delay line of a configuration that enables the combination of high-speed operation with long scan range. We compare the achievable maximum delay of several delay line configurations, and identify the configurations with the greatest delay range. We demonstrate the use of one such long-range delay line in a catheter-based optical coherence tomography system and present profiles of the human upper airway and esophagus in vivo with a radial scan range of 26 millimeters. Such quantitative upper airway profiling should prove valuable in investigating the pathophysiology of airway collapse during sleep (obstructive sleep apnea).

Scanning, non-contact, hybrid broadband diffuse optical spectroscopy and diffuse correlation spectroscopy system.

PubMed

Johansson, Johannes D; Mireles, Miguel; Morales-Dalmau, Jordi; Farzam, Parisa; Martínez-Lozano, Mar; Casanovas, Oriol; Durduran, Turgut

2016-02-01

A scanning system for small animal imaging using non-contact, hybrid broadband diffuse optical spectroscopy (ncDOS) and diffuse correlation spectroscopy (ncDCS) is presented. The ncDOS uses a two-dimensional spectrophotometer retrieving broadband (610-900 nm) spectral information from up to fifty-seven source-detector distances between 2 and 5 mm. The ncDCS data is simultaneously acquired from four source-detector pairs. The sample is scanned in two dimensions while tracking variations in height. The system has been validated with liquid phantoms, demonstrated in vivo on a human fingertip during an arm cuff occlusion and on a group of mice with xenoimplanted renal cell carcinoma.

Actively stabilized optical fiber interferometry technique for online/in-process surface measurement.

PubMed

Wang, Kaiwei; Martin, Haydn; Jiang, Xiangqian

2008-02-01

In this paper, we report the recent progress in optical-beam scanning fiber interferometry for potential online nanoscale surface measurement based on the previous research. It attempts to generate a robust and miniature measurement device for future development into a multiprobe array measurement system. In this research, both fiber-optic-interferometry and the wavelength-division-multiplexing techniques have been used, so that the optical probe and the optical interferometer are well spaced and fast surface scanning can be carried out, allowing flexibility for online measurement. In addition, this system provides a self-reference signal to stabilize the optical detection with high common-mode noise suppression by adopting an active phase tracking and stabilization technique. Low-frequency noise was significantly reduced compared with unstabilized result. The measurement of a sample surface shows an attained repeatability of 3.3 nm.

Miniature rotating transmissive optical drum scanner

NASA Technical Reports Server (NTRS)

Lewis, Robert (Inventor); Parrington, Lawrence (Inventor); Rutberg, Michael (Inventor)

2013-01-01

A miniature rotating transmissive optical scanner system employs a drum of small size having an interior defined by a circumferential wall rotatable on a drum axis, an optical element positioned within the interior of the drum, and a light-transmissive lens aperture provided at an angular position in the circumferential wall of the drum for scanning a light beam to or from the optical element in the drum along a beam azimuth angle as the drum is rotated. The miniature optical drum scanner configuration obtains a wide scanning field-of-view (FOV) and large effective aperture is achieved within a physically small size.

Optical Distance Measurement Device And Method Thereof

DOEpatents

Bowers, Mark W.

2004-06-15

A system and method of efficiently obtaining distance measurements of a target by scanning the target. An optical beam is provided by a light source and modulated by a frequency source. The modulated optical beam is transmitted to an acousto-optical deflector capable of changing the angle of the optical beam in a predetermined manner to produce an output for scanning the target. In operation, reflected or diffused light from the target may be received by a detector and transmitted to a controller configured to calculate the distance to the target as well as the measurement uncertainty in calculating the distance to the target.

High-speed atomic force microscopy combined with inverted optical microscopy for studying cellular events

PubMed Central

Suzuki, Yuki; Sakai, Nobuaki; Yoshida, Aiko; Uekusa, Yoshitsugu; Yagi, Akira; Imaoka, Yuka; Ito, Shuichi; Karaki, Koichi; Takeyasu, Kunio

2013-01-01

A hybrid atomic force microscopy (AFM)-optical fluorescence microscopy is a powerful tool for investigating cellular morphologies and events. However, the slow data acquisition rates of the conventional AFM unit of the hybrid system limit the visualization of structural changes during cellular events. Therefore, high-speed AFM units equipped with an optical/fluorescence detection device have been a long-standing wish. Here we describe the implementation of high-speed AFM coupled with an optical fluorescence microscope. This was accomplished by developing a tip-scanning system, instead of a sample-scanning system, which operates on an inverted optical microscope. This novel device enabled the acquisition of high-speed AFM images of morphological changes in individual cells. Using this instrument, we conducted structural studies of living HeLa and 3T3 fibroblast cell surfaces. The improved time resolution allowed us to image dynamic cellular events. PMID:23823461

High-speed atomic force microscopy combined with inverted optical microscopy for studying cellular events.

PubMed

Suzuki, Yuki; Sakai, Nobuaki; Yoshida, Aiko; Uekusa, Yoshitsugu; Yagi, Akira; Imaoka, Yuka; Ito, Shuichi; Karaki, Koichi; Takeyasu, Kunio

2013-01-01

A hybrid atomic force microscopy (AFM)-optical fluorescence microscopy is a powerful tool for investigating cellular morphologies and events. However, the slow data acquisition rates of the conventional AFM unit of the hybrid system limit the visualization of structural changes during cellular events. Therefore, high-speed AFM units equipped with an optical/fluorescence detection device have been a long-standing wish. Here we describe the implementation of high-speed AFM coupled with an optical fluorescence microscope. This was accomplished by developing a tip-scanning system, instead of a sample-scanning system, which operates on an inverted optical microscope. This novel device enabled the acquisition of high-speed AFM images of morphological changes in individual cells. Using this instrument, we conducted structural studies of living HeLa and 3T3 fibroblast cell surfaces. The improved time resolution allowed us to image dynamic cellular events.

Highly sensitive LIDAR with a thumb-sized sensor-head built using an optical fiber preamplifier (3)

NASA Astrophysics Data System (ADS)

Inoue, Daisuke; Ichikawa, Tadashi; Matsubara, Hiroyuki; Kagami, Manabu

2013-05-01

We have developed a LIDAR system with a sensor head which, although it includes a scanning mechanism, is less than 20 cc in size. The system is not only small, but is also highly sensitive. Our LIDAR system is based on time-of-flight measurements, and incorporates an optical fiber. The main feature of our system is the utilization of optical amplifiers for both the transmitter and the receiver, and the optical amplifiers enable us to exceed the detection limit set by thermal noise. In conventional LIDAR systems the detection limit is determined by the thermal noise, because the avalanche photo-diodes (APD) and trans-impedance amplifiers (TIA) that they use detect the received signals directly. In the case of our LIDAR system, the received signal is amplified by an optical fiber amplifier before reaching the photo diode and the TIA. Therefore, our LIDAR system boosts the signal level before the weak incoming signal is depleted by thermal noise. There are conditions under which the noise figure for the combination of an optical fiber amplifier and a photo diode is superior to the noise figure for an avalanche photo diode. We optimized the gains of the optical fiber amplifier and the TIA in our LIDAR system such that it would be capable of detecting a single photon. As a result, the detection limit of our system is determined by shot noise. We have previously demonstrated scanning up to a range of 80 m with this LIDAR system with a 2 mm diameter of receiving lens. We improved the optical amplifier and the peak output power of LIDAR was over 10KW. We redesigned the sensor-head and improved coupling efficiency. As a result, we succeeded in scanning over a range of 100 m. This small and highly sensitive measurement technology shows great potential for use in LIDAR.

Holographic Optical Elements as Scanning Lidar Telescopes

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.

2003-01-01

We have investigated and developed the use of holographic optical elements (HOE) and holographic transmission gratings for scanning lidar telescopes. By rotating a flat HOE in its own plane with the focal spot on the rotation axis, a very simple and compact conical scanning telescope is possible. We developed and tested transmission and reflection HOES for use with the first three harmonics of Nd:YAG lasers, and designed, built, and tested two lidar systems based on this technology.

Validation of a Prototype Optical Computed Tomography System

PubMed Central

Zakariaee, Seyed Salman; Molazadeh, Mikaeil; Takavar, Abbas; Shirazi, Alireza; Mesbahi, Asghar; Zeinali, Ahad

2015-01-01

In radiation cancer treatments, the most of the side effects could be minimized using a proper dosimeter. Gel dosimeter is the only three-dimensional dosimeter and magnetic resonance imaging (MRI) is the gold standard method for gel dosimeter readout. Because of hard accessibility and high cost of sample reading by MRI systems, some other alternative methods were developed. The optical computed tomography (OCT) method could be considered as the most promising alternative method that has been studied widely. In the current study, gel dosimeter scanning using a prototype optical scanner and validation of this optical scanner was performed. Optical absorbance of the irradiated gel samples was determined by both of conventional spectrophotometer and the fabricated OCT system at 632 nm. Furthermore, these irradiated vials were scanned by a 1.5 T MRI. The slope of the curves was extracted as the dose-response sensitivity. The R2-dose sensitivity measured by MRI method was 0.1904 and 0.113 for NIPAM and PAGAT gels, respectively. The optical dose sensitivity obtained by conventional spectrophotometer and the fabricated optical scanner was 0.0453 and 0.0442 for NIPAM gels and 0.0244 and 0.0242 for PAGAT gels, respectively. The scanning results of the absorbed dose values showed that the new OCT and conventional spectrophotometer were in fair agreement. From the results, it could be concluded that the fabricated system is able to quantize the absorbed dose values in polymer gel samples with acceptable accuracy. PMID:26120572

Water-Immersible MEMS scanning mirror designed for wide-field fast-scanning photoacoustic microscopy

NASA Astrophysics Data System (ADS)

Yao, Junjie; Huang, Chih-Hsien; Martel, Catherine; Maslov, Konstantin I.; Wang, Lidai; Yang, Joon-Mo; Gao, Liang; Randolph, Gwendalyn; Zou, Jun; Wang, Lihong V.

2013-03-01

By offering images with high spatial resolution and unique optical absorption contrast, optical-resolution photoacoustic microscopy (OR-PAM) has gained increasing attention in biomedical research. Recent developments in OR-PAM have improved its imaging speed, but have sacrificed either the detection sensitivity or field of view or both. We have developed a wide-field fast-scanning OR-PAM by using a water-immersible MEMS scanning mirror (MEMS-ORPAM). Made of silicon with a gold coating, the MEMS mirror plate can reflect both optical and acoustic beams. Because it uses an electromagnetic driving force, the whole MEMS scanning system can be submerged in water. In MEMS-ORPAM, the optical and acoustic beams are confocally configured and simultaneously steered, which ensures uniform detection sensitivity. A B-scan imaging speed as high as 400 Hz can be achieved over a 3 mm scanning range. A diffraction-limited lateral resolution of 2.4 μm in water and a maximum imaging depth of 1.1 mm in soft tissue have been experimentally determined. Using the system, we imaged the flow dynamics of both red blood cells and carbon particles in a mouse ear in vivo. By using Evans blue dye as the contrast agent, we also imaged the flow dynamics of lymphatic vessels in a mouse tail in vivo. The results show that MEMS-OR-PAM could be a powerful tool for studying highly dynamic and time-sensitive biological phenomena.

Fast Industrial Inspection of Optical Thin Film Using Optical Coherence Tomography

PubMed Central

Shirazi, Muhammad Faizan; Park, Kibeom; Wijesinghe, Ruchire Eranga; Jeong, Hyosang; Han, Sangyeob; Kim, Pilun; Jeon, Mansik; Kim, Jeehyun

2016-01-01

An application of spectral domain optical coherence tomography (SD-OCT) was demonstrated for a fast industrial inspection of an optical thin film panel. An optical thin film sample similar to a liquid crystal display (LCD) panel was examined. Two identical SD-OCT systems were utilized for parallel scanning of a complete sample in half time. Dual OCT inspection heads were utilized for transverse (fast) scanning, while a stable linear motorized translational stage was used for lateral (slow) scanning. The cross-sectional and volumetric images of an optical thin film sample were acquired to detect the defects in glass and other layers that are difficult to observe using visual inspection methods. The rapid inspection enabled by this setup led to the early detection of product defects on the manufacturing line, resulting in a significant improvement in the quality assurance of industrial products. PMID:27690043

Conically scanned lidar telescope using holographic optical elements

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K.; Wilkerson, Thomas D.

1992-01-01

Holographic optical elements (HOE) using volume phase holograms make possible a new class of lightweight scanning telescopes having advantages for lidar remote sensing instruments. So far, the only application of HOE's to lidar has been a non-scanning receiver for a laser range finder. We introduce a large aperture, narrow field of view (FOV) telescope used in a conical scanning configuration, having a much smaller rotating mass than in conventional designs. Typically, lidars employ a large aperture collector and require a narrow FOV to limit the amount of skylight background. Focal plane techniques are not good approaches to scanning because they require a large FOV within which to scan a smaller FOV mirror or detector array. Thus, scanning lidar systems have either used a large flat scanning mirror at which the receiver telescope is pointed, or the entire telescope is steered. We present a concept for a conically scanned lidar telescope in which the only moving part is the HOE which serves as the primary collecting optic. We also describe methods by which a multiplexed HOE can be used simultaneously as a dichroic beamsplitter.

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

PubMed Central

Araujo, Karolline A S; Cury, Luiz A; Matos, Matheus J S; Fernandes, Thales F D; Cançado, Luiz G

2018-01-01

The influence of graphene and retinoic acid (RA) – a π-conjugated organic semiconductor – interface on their hybrid system is investigated. The physical properties of the interface are assessed via scanning probe microscopy, optical spectroscopy (photoluminescence and Raman) and ab initio calculations. The graphene/RA interaction induces the formation of a well-organized π-conjugated self-assembled monolayer (SAM) at the interface. Such structural organization leads to the high optical emission efficiency of the RA SAM, even at room temperature. Additionally, photo-assisted electrical force microscopy, photo-assisted scanning Kelvin probe microscopy and Raman spectroscopy indicate a RA-induced graphene doping and photo-charge generation. Finally, the optical excitation of the RA monolayer generates surface potential changes on the hybrid system. In summary, interface-induced organized structures atop 2D materials may have an important impact on both design and operation of π-conjugated nanomaterial-based hybrid systems. PMID:29600157

Surface profile measurement by using the integrated Linnik WLSI and confocal microscope system

NASA Astrophysics Data System (ADS)

Wang, Wei-Chung; Shen, Ming-Hsing; Hwang, Chi-Hung; Yu, Yun-Ting; Wang, Tzu-Fong

2017-06-01

The white-light scanning interferometer (WLSI) and confocal microscope (CM) are the two major optical inspection systems for measuring three-dimensional (3D) surface profile (SP) of micro specimens. Nevertheless, in practical applications, WLSI is more suitable for measuring smooth and low-slope surfaces. On the other hand, CM is more suitable for measuring uneven-reflective and low-reflective surfaces. As for aspect of surface profiles to be measured, the characteristics of WLSI and CM are also different. WLSI is generally used in semiconductor industry while CM is more popular in printed circuit board industry. In this paper, a self-assembled multi-function optical system was integrated to perform Linnik white-light scanning interferometer (Linnik WLSI) and CM. A connecting part composed of tubes, lenses and interferometer was used to conjunct finite and infinite optical systems for Linnik WLSI and CM in the self-assembled optical system. By adopting the flexibility of tubes and lenses, switching to perform two different optical measurements can be easily achieved. Furthermore, based on the shape from focus method with energy of Laplacian filter, the CM was developed to enhance the on focal information of each pixel so that the CM can provide all-in-focus image for performing the 3D SP measurement and analysis simultaneously. As for Linnik WLSI, eleven-step phase shifting algorithm was used to analyze vertical scanning signals and determine the 3D SP.

Accuracy assessment of high frequency 3D ultrasound for digital impression-taking of prepared teeth

NASA Astrophysics Data System (ADS)

Heger, Stefan; Vollborn, Thorsten; Tinschert, Joachim; Wolfart, Stefan; Radermacher, Klaus

2013-03-01

Silicone based impression-taking of prepared teeth followed by plaster casting is well-established but potentially less reliable, error-prone and inefficient, particularly in combination with emerging techniques like computer aided design and manufacturing (CAD/CAM) of dental prosthesis. Intra-oral optical scanners for digital impression-taking have been introduced but until now some drawbacks still exist. Because optical waves can hardly penetrate liquids or soft-tissues, sub-gingival preparations still need to be uncovered invasively prior to scanning. High frequency ultrasound (HFUS) based micro-scanning has been recently investigated as an alternative to optical intra-oral scanning. Ultrasound is less sensitive against oral fluids and in principal able to penetrate gingiva without invasively exposing of sub-gingival preparations. Nevertheless, spatial resolution as well as digitization accuracy of an ultrasound based micro-scanning system remains a critical parameter because the ultrasound wavelength in water-like media such as gingiva is typically smaller than that of optical waves. In this contribution, the in-vitro accuracy of ultrasound based micro-scanning for tooth geometry reconstruction is being investigated and compared to its extra-oral optical counterpart. In order to increase the spatial resolution of the system, 2nd harmonic frequencies from a mechanically driven focused single element transducer were separated and corresponding 3D surface models were calculated for both fundamentals and 2nd harmonics. Measurements on phantoms, model teeth and human teeth were carried out for evaluation of spatial resolution and surface detection accuracy. Comparison of optical and ultrasound digital impression taking indicate that, in terms of accuracy, ultrasound based tooth digitization can be an alternative for optical impression-taking.

Long-range time-of-flight scanning sensor based on high-speed time-correlated single-photon counting

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

McCarthy, Aongus; Collins, Robert J.; Krichel, Nils J.

2009-11-10

We describe a scanning time-of-flight system which uses the time-correlated single-photon counting technique to produce three-dimensional depth images of distant, noncooperative surfaces when these targets are illuminated by a kHz to MHz repetition rate pulsed laser source. The data for the scene are acquired using a scanning optical system and an individual single-photon detector. Depth images have been successfully acquired with centimeter xyz resolution, in daylight conditions, for low-signature targets in field trials at distances of up to 325 m using an output illumination with an average optical power of less than 50 {mu}W.

Development of a hybrid atomic force microscopic measurement system combined with white light scanning interferometry.

PubMed

Guo, Tong; Wang, Siming; Dorantes-Gonzalez, Dante J; Chen, Jinping; Fu, Xing; Hu, Xiaotang

2012-01-01

A hybrid atomic force microscopic (AFM) measurement system combined with white light scanning interferometry for micro/nanometer dimensional measurement is developed. The system is based on a high precision large-range positioning platform with nanometer accuracy on which a white light scanning interferometric module and an AFM head are built. A compact AFM head is developed using a self-sensing tuning fork probe. The head need no external optical sensors to detect the deflection of the cantilever, which saves room on the head, and it can be directly fixed under an optical microscopic interferometric system. To enhance the system's dynamic response, the frequency modulation (FM) mode is adopted for the AFM head. The measuring data can be traceable through three laser interferometers in the system. The lateral scanning range can reach 25 mm × 25 mm by using a large-range positioning platform. A hybrid method combining AFM and white light scanning interferometry is proposed to improve the AFM measurement efficiency. In this method, the sample is measured firstly by white light scanning interferometry to get an overall coarse morphology, and then, further measured with higher resolution by AFM. Several measuring experiments on standard samples demonstrate the system's good measurement performance and feasibility of the hybrid measurement method.

Optics detection and laser countermeasures on a combat vehicle

NASA Astrophysics Data System (ADS)

Sjöqvist, Lars; Allard, Lars; Pettersson, Magnus; Börjesson, Per; Lindskog, Nils; Bodin, Johan; Widén, Anders; Persson, Hâkan; Fredriksson, Jan; Edström, Sten

2016-10-01

Magnifying optical assemblies used for weapon guidance or rifle scopes may possess a threat for a combat vehicle and its personnel. Detection and localisation of optical threats is consequently of interest in military applications. Typically a laser system is used in optics detection, or optical augmentation, to interrogate a scene of interest to localise retroreflected laser radiation. One interesting approach for implementing optics detection on a combat vehicle is to use a continuous scanning scheme. In addition, optics detection can be combined with laser countermeasures, or a laser dazzling function, to efficiently counter an optical threat. An optics detection laser sensor demonstrator has been implemented on a combat vehicle. The sensor consists of a stabilised gimbal and was integrated together with a LEMUR remote electro-optical sight. A narrow laser slit is continuously scanned around the horizon to detect and locate optical threats. Detected threats are presented for the operator within the LEMUR presentation system, and by cueing a countermeasure laser installed in the LEMUR sensor housing threats can be defeated. Results obtained during a field demonstration of the optics detection sensor and the countermeasure laser will be presented. In addition, results obtained using a dual-channel optics detection system designed for false alarm reduction are also discussed.

Design and experimental validation of novel 3D optical scanner with zoom lens unit

NASA Astrophysics Data System (ADS)

Huang, Jyun-Cheng; Liu, Chien-Sheng; Chiang, Pei-Ju; Hsu, Wei-Yan; Liu, Jian-Liang; Huang, Bai-Hao; Lin, Shao-Ru

2017-10-01

Optical scanners play a key role in many three-dimensional (3D) printing and CAD/CAM applications. However, existing optical scanners are generally designed to provide either a wide scanning area or a high 3D reconstruction accuracy from a lens with a fixed focal length. In the former case, the scanning area is increased at the expense of the reconstruction accuracy, while in the latter case, the reconstruction performance is improved at the expense of a more limited scanning range. In other words, existing optical scanners compromise between the scanning area and the reconstruction accuracy. Accordingly, the present study proposes a new scanning system including a zoom-lens unit, which combines both a wide scanning area and a high 3D reconstruction accuracy. In the proposed approach, the object is scanned initially under a suitable low-magnification setting for the object size (setting 1), resulting in a wide scanning area but a poor reconstruction resolution in complicated regions of the object. The complicated regions of the object are then rescanned under a high-magnification setting (setting 2) in order to improve the accuracy of the original reconstruction results. Finally, the models reconstructed after each scanning pass are combined to obtain the final reconstructed 3D shape of the object. The feasibility of the proposed method is demonstrated experimentally using a laboratory-built prototype. It is shown that the scanner has a high reconstruction accuracy over a large scanning area. In other words, the proposed optical scanner has significant potential for 3D engineering applications.

Applications of Adaptive Optics Scanning Laser Ophthalmoscopy

PubMed Central

Roorda, Austin

2010-01-01

Adaptive optics (AO) describes a set of tools to correct or control aberrations in any optical system. In the eye, AO allows for precise control of the ocular aberrations. If used to correct aberrations over a large pupil, for example, cellular level resolution in retinal images can be achieved. AO systems have been demonstrated for advanced ophthalmoscopy as well as for testing and/or improving vision. In fact, AO can be integrated to any ophthalmic instrument where the optics of the eye is involved, with a scope of applications ranging from phoropters to optical coherence tomography systems. In this paper, I discuss the applications and advantages of using AO in a specific system, the adaptive optics scanning laser ophthalmoscope, or AOSLO. Since the Borish award was, in part, awarded to me because of this effort, I felt it appropriate to select this as the topic for this paper. Furthermore, users of AOSLO continue to appreciate the benefits of the technology, some of which were not anticipated at the time of development, and so it is time to revisit this topic and summarize them in a single paper. PMID:20160657

Multimodal ophthalmic imaging using swept source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography

NASA Astrophysics Data System (ADS)

Malone, Joseph D.; El-Haddad, Mohamed T.; Tye, Logan A.; Majeau, Lucas; Godbout, Nicolas; Rollins, Andrew M.; Boudoux, Caroline; Tao, Yuankai K.

2016-03-01

Scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) benefit clinical diagnostic imaging in ophthalmology by enabling in vivo noninvasive en face and volumetric visualization of retinal structures, respectively. Spectrally encoding methods enable confocal imaging through fiber optics and reduces system complexity. Previous applications in ophthalmic imaging include spectrally encoded confocal scanning laser ophthalmoscopy (SECSLO) and a combined SECSLO-OCT system for image guidance, tracking, and registration. However, spectrally encoded imaging suffers from speckle noise because each spectrally encoded channel is effectively monochromatic. Here, we demonstrate in vivo human retinal imaging using a swept source spectrally encoded scanning laser ophthalmoscope and OCT (SSSESLO- OCT) at 1060 nm. SS-SESLO-OCT uses a shared 100 kHz Axsun swept source, shared scanner and imaging optics, and are detected simultaneously on a shared, dual channel high-speed digitizer. SESLO illumination and detection was performed using the single mode core and multimode inner cladding of a double clad fiber coupler, respectively, to preserve lateral resolution while improving collection efficiency and reducing speckle contrast at the expense of confocality. Concurrent en face SESLO and cross-sectional OCT images were acquired with 1376 x 500 pixels at 200 frames-per-second. Our system design is compact and uses a shared light source, imaging optics, and digitizer, which reduces overall system complexity and ensures inherent co-registration between SESLO and OCT FOVs. En face SESLO images acquired concurrent with OCT cross-sections enables lateral motion tracking and three-dimensional volume registration with broad applications in multivolume OCT averaging, image mosaicking, and intraoperative instrument tracking.

Enabling freehand lateral scanning of optical coherence tomography needle probes with a magnetic tracking system

PubMed Central

Yeo, Boon Y.; McLaughlin, Robert A.; Kirk, Rodney W.; Sampson, David D.

2012-01-01

We present a high-resolution three-dimensional position tracking method that allows an optical coherence tomography (OCT) needle probe to be scanned laterally by hand, providing the high degree of flexibility and freedom required in clinical usage. The method is based on a magnetic tracking system, which is augmented by cross-correlation-based resampling and a two-stage moving window average algorithm to improve upon the tracker's limited intrinsic spatial resolution, achieving 18 µm RMS position accuracy. A proof-of-principle system was developed, with successful image reconstruction demonstrated on phantoms and on ex vivo human breast tissue validated against histology. This freehand scanning method could contribute toward clinical implementation of OCT needle imaging. PMID:22808429

Design and evaluation of an intraocular B-scan OCT-guided 36-gauge needle

NASA Astrophysics Data System (ADS)

Shen, Jin H.; Joos, Karen M.

2015-03-01

Optical coherence tomography imaging is widely used in ophthalmology and optometry clinics for diagnosing retinal disorders. External microscope-mounted OCT operating room systems have imaged retinal changes immediately following surgical manipulations. However, the goal is to image critical surgical maneuvers in real time. External microscope-mounted OCT systems have some limitations with problems tracking constantly moving intraocular surgical instruments, and formation of absolute shadows by the metallic surgical instruments upon the underlying tissues of interest. An intraocular OCT-imaging probe was developed to resolve these problems. A disposable 25-gauge probe tip extended beyond the handpiece, with a 36-gauge needle welded to a disposable tip with its end extending an additional 3.5 mm. A sealed 0.35 mm diameter GRIN lens protected the fiber scanner and focused the scanning beam at a 3 to 4 mm distance. The OCT engine was a very high-resolution spectral-domain optical coherence tomography (SDOCT) system (870 nm, Bioptigen, Inc. Durham, NC) which produced 2000 A-scan lines per B-scan image at a frequency of 5 Hz with the fiber optic oscillations matched to this frequency. Real-time imaging of the needle tip as it touched infrared paper was performed. The B-scan OCT-needle was capable of real-time performance and imaging of the phantom material. In the future, the B-scan OCT-guided needle will be used to perform sub-retinal injections.

A scanning defect mapping system for semiconductor characterization

NASA Technical Reports Server (NTRS)

Sopori, Bushnan L.

1994-01-01

We have developed an optical scanning system that generates maps of the spatial distributions of defects in single and polycrystalline silicon wafers. This instrument, called Scanning Defect Mapping System, utilizes differences in the scattering characteristics of dislocation etch pits and grain boundaries from a defect-etched sample to identify and count them. This system simultaneously operates in the dislocation mode and the grain boundary (GB) mode. In the 'dislocation mode,' the optical scattering from the etch pits is used to statistically count dislocations, while ignoring the GB's. Likewise, in the 'grain boundary mode' the system only recognizes the local scattering from the GB's to generate grain boundary distributions. The information generated by this instrument is valuable for material quality control, identifying mechanisms of defect generation and the nature of thermal stresses during the crystal growth, and the solar cell process design.

Effects of pupil filter patterns in line-scan focal modulation microscopy

NASA Astrophysics Data System (ADS)

Shen, Shuhao; Pant, Shilpa; Chen, Rui; Chen, Nanguang

2018-03-01

Line-scan focal modulation microscopy (LSFMM) is an emerging imaging technique that affords high imaging speed and good optical sectioning at the same time. We present a systematic investigation into optimal design of the pupil filter for LSFMM in an attempt to achieve the best performance in terms of spatial resolutions, optical sectioning, and modulation depth. Scalar diffraction theory was used to compute light propagation and distribution in the system and theoretical predictions on system performance, which were then compared with experimental results.

Heterodyne Interferometry with a Scanning Optical Microscope.

NASA Astrophysics Data System (ADS)

Hobbs, Philip Charles Danby

The design and implementation of a confocal optical microscope which functions as an electronically scanned heterodyne interferometer are described. Theoretical models based on Fourier optics for general samples and on exact series solution of the scalar Helmholtz equation for a class of trench structures are developed and compared with experimental data. Good agreement is obtained. The associated data acquisition system, also described, enables the system to measure both the amplitude (to 12 bits) and the phase (to 0.1^circ) of a returned optical beam, at a continuous rate of 30,000 points per second. The microscope system uses a wide-band tellurium dioxide acousto-optic cell for electronic scanning, frequency shifting, and beam splitting/combining. It uses a stationary reference beam on the sample for vibration cancellation, which results in a system of great vibration immunity. It can measure relief ranging from a few tenths of a micron down to a few Angstroms, and line widths down to well below 0.4 micron, using light of 0.5 micron wavelength. Angstrom resolution can be achieved in a single full-speed scan, without special vibration isolation equipment, providing that folding mirrors are avoided. A signal processing algorithm based on Fourier deconvolution is presented; it takes advantage of the extra bandwidth of a confocal system and the availability of both amplitude and phase, to improve the lateral resolution by approximately a factor of two. Experimental results are shown, which demonstrate phase edge resolution (10%-90%) of 0.45 lambda (raw data), and 0.18 lambda (after filtering), in excellent agreement with the Fourier optics prediction. The exact scalar theory calculates the response of the microscope as it scans over an infinitely long rectangular trench in a plane boundary on which Dirichlet boundary conditions apply. An expansion in cavity modes inside the trench is used to match the field and its derivatives across the mouth of the trench to get the self-consistent solution. A listing is appended of a program for an HP personal computer which performs the simulation in 1 to 5 minutes' running time for most cases. The trench theory is compared with the Fourier theory and with experimental results for actual metal trenches, with good results.

A novel design of a scanning probe microscope integrated with an ultramicrotome for serial block-face nanotomography

NASA Astrophysics Data System (ADS)

Efimov, Anton E.; Agapov, Igor I.; Agapova, Olga I.; Oleinikov, Vladimir A.; Mezin, Alexey V.; Molinari, Michael; Nabiev, Igor; Mochalov, Konstantin E.

2017-02-01

We present a new concept of a combined scanning probe microscope (SPM)/ultramicrotome apparatus. It enables "slice-and-view" scanning probe nanotomography measurements and 3D reconstruction of the bulk sample nanostructure from series of SPM images after consecutive ultrathin sections. The sample is fixed on a flat XYZ scanning piezostage mounted on the ultramicrotome arm. The SPM measuring head with a cantilever tip and a laser-photodiode tip detection system approaches the sample for SPM measurements of the block-face surface immediately after the ultramicrotome sectioning is performed. The SPM head is moved along guides that are also fixed on the ultramicrotome arm. Thereby, relative dysfunctional displacements of the tip, the sample, and the ultramicrotome knife are minimized. The design of the SPM head enables open frontal optical access to the sample block-face adapted for high-resolution optical lenses for correlative SPM/optical microscopy applications. The new system can be used in a wide range of applications for the study of 3D nanostructures of biological objects, biomaterials, polymer nanocomposites, and nanohybrid materials in various SPM and optical microscopy measuring modes.

Dual Optical Levers for Atomic Force Microscopy

NASA Astrophysics Data System (ADS)

Kawakatsu, Hideki; Bleuler, Hannes; Saito, Takashi; Hiroshi, Kougami

1995-06-01

Development of micro machined cantilever and optical lever detection system has greatly facilitated the operation of atomic force microscopy. However, since the detection system measures only the deflection of the cantilever at one set point where the laser beam is focused, care must be taken in implementing force control or in interpreting the acquired data. In this paper, a dual optical lever detection system is introduced, which has the potential to resolve the deformation of the cantilever with multidegree of freedom and thus detect the position of the tip end point with resolution in the 10 pm order. The detection system proved to be effective in real-time monitoring of the behavior of the tip end point while scanning, and in explaining the scanning direction dependence of the acquired images.

Scanning digital lithography providing high speed large area patterning with diffraction limited sub-micron resolution

NASA Astrophysics Data System (ADS)

Wen, Sy-Bor; Bhaskar, Arun; Zhang, Hongjie

2018-07-01

A scanning digital lithography system using computer controlled digital spatial light modulator, spatial filter, infinity correct optical microscope and high precision translation stage is proposed and examined. Through utilizing the spatial filter to limit orders of diffraction modes for light delivered from the spatial light modulator, we are able to achieve diffraction limited deep submicron spatial resolution with the scanning digital lithography system by using standard one inch level optical components with reasonable prices. Raster scanning of this scanning digital lithography system using a high speed high precision x-y translation stage and piezo mount to real time adjust the focal position of objective lens allows us to achieve large area sub-micron resolved patterning with high speed (compared with e-beam lithography). It is determined in this study that to achieve high quality stitching of lithography patterns with raster scanning, a high-resolution rotation stage will be required to ensure the x and y directions of the projected pattern are in the same x and y translation directions of the nanometer precision x-y translation stage.

System and Method for Scan Range Gating

NASA Technical Reports Server (NTRS)

Lindemann, Scott (Inventor); Zuk, David M. (Inventor)

2017-01-01

A system for scanning light to define a range gated signal includes a pulsed coherent light source that directs light into the atmosphere, a light gathering instrument that receives the light modified by atmospheric backscatter and transfers the light onto an image plane, a scanner that scans collimated light from the image plane to form a range gated signal from the light modified by atmospheric backscatter, a control circuit that coordinates timing of a scan rate of the scanner and a pulse rate of the pulsed coherent light source so that the range gated signal is formed according to a desired range gate, an optical device onto which an image of the range gated signal is scanned, and an interferometer to which the image of the range gated signal is directed by the optical device. The interferometer is configured to modify the image according to a desired analysis.

Imaging of human finger nail-fold with MHz A-scan rate swept source optical coherence tomography

NASA Astrophysics Data System (ADS)

Poddar, Raju; Mondal, Indranil

2018-07-01

We present a non-invasive three-dimensional depth-resolved micro-structure and micro-vasculature imaging of a human fingernail-fold with a swept-source optical coherence tomography (ssOCT) system at a 1064 nm center wavelength. A phase variance OCT angiography (OCTA) method was implemented for motion contrast OCT imaging. A Fourier-domain mode-locked light source with an A-scan rate of 1.7 MHz (1 700 000 A-scans s‑1) was utilized for imaging. The experimental setup demonstrates OCT and OCTA imaging with an area of ~5 mm  ×  5 mm (within the Nyquist limit). Details of the ssOCTA system such as system parameters, scanning protocols, acquisition time, challenges, and scanning density are discussed. The selected features of the nail-fold structure and vascular networks are also deliberated. The system has potential for real-time monitoring of transdermal drug delivery, and the management and diagnosis of various diseases such as connective tissue diseases and Raynaud’s phenomenon.

Combined optical resolution photoacoustic and fluorescence micro-endoscopy

NASA Astrophysics Data System (ADS)

Shao, Peng; Shi, Wei; Hajireza, Parsin; Zemp, Roger J.

2012-02-01

We present a new micro-endoscopy system combining real-time C-scan optical-resolution photoacoustic micro-endoscopy (OR-PAME), and a high-resolution fluorescence micro-endoscopy system for visualizing fluorescently labeled cellular components and optically absorbing microvasculature simultaneously. With a diode-pumped 532-nm fiber laser, the OR-PAM sub-system is capable of imaging with a resolution of ~ 7μm. The fluorescence sub-system consists of a diode laser with 445 nm-centered emissions as the light source, an objective lens and a CCD camera. Proflavine, a FDA approved drug for human use, is used as the fluorescent contrast agent by topical application. The fluorescence system does not require any mechanical scanning. The scanning laser and the diode laser light source share the same light path within an optical fiber bundle containing 30,000 individual single mode fibers. The absorption of Proflavine at 532 nm is low, which mitigates absorption bleaching of the contrast agent by the photoacoustic excitation source. We demonstrate imaging in live murine models. The system is able to provide cellular morphology with cellular resolution co-registered with the structural and functional information given by OR-PAM. Therefore, the system has the potential to serve as a virtual biopsy technique, helping researchers and clinicians visualize angiogenesis, effects of anti-cancer drugs on both cells and the microcirculation, as well as aid in the study of other diseases.

Fiber optic-based optical coherence tomography (OCT) for dental applications

NASA Astrophysics Data System (ADS)

Everett, Matthew J.; Colston, Bill W., Jr.; Da Silva, Luiz B.; Otis, Linda L.

1998-09-01

We have developed a hand-held fiber optic based optical coherence tomography (OCT) system for scanning of the oral cavity. We have produced, using this scanning device, in vivo cross-sectional images of hard and soft dental tissues in human volunteers. Clinically relevant anatomical structures, including the gingival margin, periodontal sulcus, and dento- enamel junction, were visible in all the images. The cemento- enamel junction and the alveolar bone were identified in approximately two thirds of the images. These images represent, or our knowledge, the first in vivo OCT images of human dental tissue.

MEMS-tunable dielectric metasurface lens.

PubMed

Arbabi, Ehsan; Arbabi, Amir; Kamali, Seyedeh Mahsa; Horie, Yu; Faraji-Dana, MohammadSadegh; Faraon, Andrei

2018-02-23

Varifocal lenses, conventionally implemented by changing the axial distance between multiple optical elements, have a wide range of applications in imaging and optical beam scanning. The use of conventional bulky refractive elements makes these varifocal lenses large, slow, and limits their tunability. Metasurfaces, a new category of lithographically defined diffractive devices, enable thin and lightweight optical elements with precisely engineered phase profiles. Here we demonstrate tunable metasurface doublets, based on microelectromechanical systems (MEMS), with more than 60 diopters (about 4%) change in the optical power upon a 1-μm movement of one metasurface, and a scanning frequency that can potentially reach a few kHz. They can also be integrated with a third metasurface to make compact microscopes (~1 mm thick) with a large corrected field of view (~500 μm or 40 degrees) and fast axial scanning for 3D imaging. This paves the way towards MEMS-integrated metasurfaces as a platform for tunable and reconfigurable optics.

Doppler optical coherence tomography of retinal circulation.

PubMed

Tan, Ou; Wang, Yimin; Konduru, Ranjith K; Zhang, Xinbo; Sadda, SriniVas R; Huang, David

2012-09-18

Noncontact retinal blood flow measurements are performed with a Fourier domain optical coherence tomography (OCT) system using a circumpapillary double circular scan (CDCS) that scans around the optic nerve head at 3.40 mm and 3.75 mm diameters. The double concentric circles are performed 6 times consecutively over 2 sec. The CDCS scan is saved with Doppler shift information from which flow can be calculated. The standard clinical protocol calls for 3 CDCS scans made with the OCT beam passing through the superonasal edge of the pupil and 3 CDCS scan through the inferonal pupil. This double-angle protocol ensures that acceptable Doppler angle is obtained on each retinal branch vessel in at least 1 scan. The CDCS scan data, a 3-dimensional volumetric OCT scan of the optic disc scan, and a color photograph of the optic disc are used together to obtain retinal blood flow measurement on an eye. We have developed a blood flow measurement software called "Doppler optical coherence tomography of retinal circulation" (DOCTORC). This semi-automated software is used to measure total retinal blood flow, vessel cross section area, and average blood velocity. The flow of each vessel is calculated from the Doppler shift in the vessel cross-sectional area and the Doppler angle between the vessel and the OCT beam. Total retinal blood flow measurement is summed from the veins around the optic disc. The results obtained at our Doppler OCT reading center showed good reproducibility between graders and methods (<10%). Total retinal blood flow could be useful in the management of glaucoma, other retinal diseases, and retinal diseases. In glaucoma patients, OCT retinal blood flow measurement was highly correlated with visual field loss (R(2)>0.57 with visual field pattern deviation). Doppler OCT is a new method to perform rapid, noncontact, and repeatable measurement of total retinal blood flow using widely available Fourier-domain OCT instrumentation. This new technology may improve the practicality of making these measurements in clinical studies and routine clinical practice.

The correction of vibration in frequency scanning interferometry based absolute distance measurement system for dynamic measurements

NASA Astrophysics Data System (ADS)

Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Zhuang, Zhitao; Xu, Xinke; Gan, Yu

2015-10-01

Absolute distance measurement systems are of significant interest in the field of metrology, which could improve the manufacturing efficiency and accuracy of large assemblies in fields such as aircraft construction, automotive engineering, and the production of modern windmill blades. Frequency scanning interferometry demonstrates noticeable advantages as an absolute distance measurement system which has a high precision and doesn't depend on a cooperative target. In this paper , the influence of inevitable vibration in the frequency scanning interferometry based absolute distance measurement system is analyzed. The distance spectrum is broadened as the existence of Doppler effect caused by vibration, which will bring in a measurement error more than 103 times bigger than the changes of optical path difference. In order to decrease the influence of vibration, the changes of the optical path difference are monitored by a frequency stabilized laser, which runs parallel to the frequency scanning interferometry. The experiment has verified the effectiveness of this method.

Design of a MEMS-based retina scanning system for biometric authentication

NASA Astrophysics Data System (ADS)

Woittennek, Franziska; Knobbe, Jens; Pügner, Tino; Schelinski, Uwe; Grüger, Heinrich

2014-05-01

There is an increasing need for reliable authentication for a number of applications such as e commerce. Common authentication methods based on ownership (ID card) or knowledge factors (password, PIN) are often prone to manipulations and may therefore be not safe enough. Various inherence factor based methods like fingerprint, retinal pattern or voice identifications are considered more secure. Retina scanning in particular offers both low false rejection rate (FRR) and low false acceptance rate (FAR) with about one in a million. Images of the retina with its characteristic pattern of blood vessels can be made with either a fundus camera or laser scanning methods. The present work describes the optical design of a new compact retina laser scanner which is based on MEMS (Micro Electric Mechanical System) technology. The use of a dual axis micro scanning mirror for laser beam deflection enables a more compact and robust design compared to classical systems. The scanner exhibits a full field of view of 10° which corresponds to an area of 4 mm2 on the retinal surface surrounding the optical disc. The system works in the near infrared and is designed for use under ambient light conditions, which implies a pupil diameter of 1.5 mm. Furthermore it features a long eye relief of 30 mm so that it can be conveniently used by persons wearing glasses. The optical design requirements and the optical performance are discussed in terms of spot diagrams and ray fan plots.

Optical characterization of high speed microscanners based on static slit profiling method

NASA Astrophysics Data System (ADS)

Alaa Elhady, A.; Sabry, Yasser M.; Khalil, Diaa

2017-01-01

Optical characterization of high-speed microscanners is a challenging task that usually requires special high speed, extremely expensive camera systems. This paper presents a novel simple method to characterize the scanned beam spot profile and size in high-speed optical scanners under operation. It allows measuring the beam profile and the spot sizes at different scanning angles. The method is analyzed theoretically and applied experimentally on the characterization of a Micro Electro Mechanical MEMS scanner operating at 2.6 kHz. The variation of the spot size versus the scanning angle, up to ±15°, is extracted and the dynamic bending curvature effect of the micromirror is predicted.

Strategies to improve phase-stability of ultrafast swept source optical coherence tomography for single shot imaging of transient mechanical waves at 16 kHz frame rate

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

Song, Shaozhen; Wei, Wei; Hsieh, Bao-Yu

We present single-shot phase-sensitive imaging of propagating mechanical waves within tissue, enabled by an ultrafast optical coherence tomography (OCT) system powered by a 1.628 MHz Fourier domain mode-locked (FDML) swept laser source. We propose a practical strategy for phase-sensitive measurement by comparing the phases between adjacent OCT B-scans, where the B-scan contains a number of A-scans equaling an integer number of FDML buffers. With this approach, we show that micro-strain fields can be mapped with ∼3.0 nm sensitivity at ∼16 000 fps. The system's capabilities are demonstrated on porcine cornea by imaging mechanical wave propagation launched by a pulsed UV laser beam, promisingmore » non-contact, real-time, and high-resolution optical coherence elastography.« less

Fiber-Scanned Microdisplays

NASA Technical Reports Server (NTRS)

Crossman-Bosworth, Janet; Seibel, Eric

2010-01-01

Helmet- and head-mounted display systems, denoted fiber-scanned microdisplays, have been proposed to provide information in an "augmented reality" format (meaning that the information would be optically overlaid on the user's field of view).

Optical Demonstrations with a Scanning Photodiode Array.

ERIC Educational Resources Information Center

Turman, Bobby N.

1980-01-01

Describes the photodiode array and the electrical connections necessary for it. Also shows a few of the optical demonstration possibilities-shadowgraphs for measuring small objects, interference and diffraction effects, angular resolution of an optical system, and a simple spectrometer. (Author/DS)

Optical scanning apparatus

DOEpatents

Villarreal, R.A.

1985-11-06

An optical scanner employed in a radioactive environment for reading indicia imprinted about a cylindrical surface of an article by means of an optical system including metallic reflective and mirror surfaces resistant to degradation and discoloration otherwise imparted to glass surfaces exposed to radiation is described.

Endoscopic optical coherence tomography: technologies and clinical applications [Invited

PubMed Central

Gora, Michalina J.; Suter, Melissa J.; Tearney, Guillermo J.; Li, Xingde

2017-01-01

In this paper, we review the current state of technology development and clinical applications of endoscopic optical coherence tomography (OCT). Key design and engineering considerations are discussed for most OCT endoscopes, including side-viewing and forward-viewing probes, along with different scanning mechanisms (proximal-scanning versus distal-scanning). Multi-modal endoscopes that integrate OCT with other imaging modalities are also discussed. The review of clinical applications of endoscopic OCT focuses heavily on diagnosis of diseases and guidance of interventions. Representative applications in several organ systems are presented, such as in the cardiovascular, digestive, respiratory, and reproductive systems. A brief outlook of the field of endoscopic OCT is also discussed. PMID:28663882

High-speed spectral domain polarization-sensitive OCT using a single InGaAs line-scan camera and an optical switch

NASA Astrophysics Data System (ADS)

Lee, Sang-Won; Jeong, Hyun-Woo; Kim, Beop-Min

2010-02-01

We demonstrated high-speed spectral domain polarization-sensitive optical coherence tomography (SD-PSOCT) using a single InGaAs line-scan camera and an optical switch at 1.3-μm region. The polarization-sensitive low coherence interferometer in the system was based on the original free-space PS-OCT system published by Hee et al. The horizontal and vertical polarization light rays split by polarization beam splitter were delivered and detected via an optical switch to a single spectrometer by turns instead of dual spectrometers. The SD-PSOCT system had an axial resolution of 8.2 μm, a sensitivity of 101.5 dB, and an acquisition speed of 23,496 Alines/s. We obtained the intensity, phase retardation, and fast axis orientation images of a biological tissue. In addition, we calculated the averaged axial profiles of the phase retardation in human skin.

Development of a Hybrid Atomic Force Microscopic Measurement System Combined with White Light Scanning Interferometry

PubMed Central

Guo, Tong; Wang, Siming; Dorantes-Gonzalez, Dante J.; Chen, Jinping; Fu, Xing; Hu, Xiaotang

2012-01-01

A hybrid atomic force microscopic (AFM) measurement system combined with white light scanning interferometry for micro/nanometer dimensional measurement is developed. The system is based on a high precision large-range positioning platform with nanometer accuracy on which a white light scanning interferometric module and an AFM head are built. A compact AFM head is developed using a self-sensing tuning fork probe. The head need no external optical sensors to detect the deflection of the cantilever, which saves room on the head, and it can be directly fixed under an optical microscopic interferometric system. To enhance the system’s dynamic response, the frequency modulation (FM) mode is adopted for the AFM head. The measuring data can be traceable through three laser interferometers in the system. The lateral scanning range can reach 25 mm × 25 mm by using a large-range positioning platform. A hybrid method combining AFM and white light scanning interferometry is proposed to improve the AFM measurement efficiency. In this method, the sample is measured firstly by white light scanning interferometry to get an overall coarse morphology, and then, further measured with higher resolution by AFM. Several measuring experiments on standard samples demonstrate the system’s good measurement performance and feasibility of the hybrid measurement method. PMID:22368463

A Proposal to Localize Fermi GBM GRBs Through Coordinated Scanning of the GBM Error Circle via Optical Telescopes

NASA Technical Reports Server (NTRS)

Ukwatta, T. N.; Linnemann, J. T.; Tollefson, K.; Abeysekara, A. U.; Bhat, P. N.; Sonbas, E.; Gehrels, N.

2011-01-01

We investigate the feasibility of implementing a system that will coordinate ground-based optical telescopes to cover the Fermi GBM Error Circle (EC). The aim of the system is to localize GBM detected GRBs and facilitate multi-wavelength follow-up from space and ground. This system will optimize the observing locations in the GBM EC based on individual telescope location, Field of View (FoV) and sensitivity. The proposed system will coordinate GBM EC scanning by professional as well as amateur astronomers around the world. The results of a Monte Carlo simulation to investigate the feasibility of the project are presented.

Integrated micro-endoscopy system for simultaneous fluorescence and optical-resolution photoacoustic imaging.

PubMed

Shao, Peng; Shi, Wei; Hajireza, Parsin; Zemp, Roger J

2012-07-01

We present a new integrated micro-endoscopy system combining label-free, fiber-based, real-time C-scan optical-resolution photoacoustic microscopy (F-OR-PAM) and a high-resolution fluorescence micro-endoscopy system for visualizing fluorescently labeled cellular components and optically absorbing microvasculature simultaneously. With a diode-pumped 532-nm fiber laser, the F-OR-PAM sub-system is able to reach a resolution of ∼7  μm. The fluorescence subsystem, which does not require any mechanical scanning, consists of a 447.5-nm-centered diode laser as the light source, an objective lens, and a CCD camera. Proflavine is used as the fluorescent contrast agent by topical application. The scanning laser and the diode laser light source share the same light path within an optical fiber bundle containing 30,000 individual single-mode fibers. The absorption of proflavine at 532 nm is low, which mitigates absorption bleaching of the contrast agent by the photoacoustic excitation source. We demonstrate imaging in live murine models. The system is able to provide cellular morphology with cellular resolution co-registered with the structural information given by F-OR-PAM. Therefore, the system has the potential to serve as a virtual biopsy technique, helping visualize angiogenesis and the effects of anti-cancer drugs on both cells and the microcirculation, as well as aid in the study of other diseases.

Integrated micro-endoscopy system for simultaneous fluorescence and optical-resolution photoacoustic imaging

NASA Astrophysics Data System (ADS)

Shao, Peng; Shi, Wei; Hajireza, Parsin; Zemp, Roger J.

2012-07-01

We present a new integrated micro-endoscopy system combining label-free, fiber-based, real-time C-scan optical-resolution photoacoustic microscopy (F-OR-PAM) and a high-resolution fluorescence micro-endoscopy system for visualizing fluorescently labeled cellular components and optically absorbing microvasculature simultaneously. With a diode-pumped 532-nm fiber laser, the F-OR-PAM sub-system is able to reach a resolution of ~7 μm. The fluorescence subsystem, which does not require any mechanical scanning, consists of a 447.5-nm-centered diode laser as the light source, an objective lens, and a CCD camera. Proflavine is used as the fluorescent contrast agent by topical application. The scanning laser and the diode laser light source share the same light path within an optical fiber bundle containing 30,000 individual single-mode fibers. The absorption of proflavine at 532 nm is low, which mitigates absorption bleaching of the contrast agent by the photoacoustic excitation source. We demonstrate imaging in live murine models. The system is able to provide cellular morphology with cellular resolution co-registered with the structural information given by F-OR-PAM. Therefore, the system has the potential to serve as a virtual biopsy technique, helping visualize angiogenesis and the effects of anti-cancer drugs on both cells and the microcirculation, as well as aid in the study of other diseases.

Integrated wide-angle scanner based on translating a curved mirror of acylindrical shape.

PubMed

Sabry, Yasser M; Khalil, Diaa; Saadany, Bassam; Bourouina, Tarik

2013-06-17

A wide angle microscanning architecture is presented in which the angular deflection is achieved by displacing the principle axis of a curved silicon micromirror of acylindrical shape, with respect to the incident beam optical axis. The micromirror curvature is designed to overcome the possible deformation of the scanned beam spot size during scanning. In the presented architecture, the optical axis of the beam lays in-plane with respect to the substrate opening the door for a completely integrated and self-aligned miniaturized scanner. A micro-optical bench scanning device, based on translating a 200 μm focal length micromirror by an electrostatic comb-drive actuator, is implemented on a silicon chip. The microelectromechanical system has a resonance frequency of 329 Hz and a quality factor of 22. A single-mode optical fiber is used as the optical source and inserted into a micromachined groove fabricated and lithographically aligned with the microbench. Optical deflection angles up to 110 degrees are demonstrated.

Line scanning time-of-flight laser sensor for intelligent transport systems, combining wide field-of-view optics of 30 deg, high scanning speed of 0.9 ms/line, and simple sensor configuration

NASA Astrophysics Data System (ADS)

Imaki, Masaharu; Kameyama, Shumpei; Ishimura, Eitaro; Nakaji, Masaharu; Yoshinaga, Hideo; Hirano, Yoshihito

2017-03-01

We developed a line scanning time-of-flight (TOF) laser sensor for an intelligent transport system (ITS), which combines wide field-of-view (FOV) receiving optics of 30 deg and a high-speed microelectro mechanical system scanner of 0.9 ms/line with a simple sensor configuration. The newly developed high-aspect ratio photodiode realizes the scanless and wide FOV receiver. The sinusoidal wave intensity modulation method is used for the TOF measurement. This enables the noise reduction of the trans-impedance amplifier by applying the LC-resonant method. The vehicle detection and axle counting, which are the important functions in ITS, are also demonstrated.

Optics in the United kingdom.

PubMed

Ditchburn, R W

1969-10-01

Optics is interpreted to include x-ray optics, electronic optics, and short wave radiooptics as well as the more conventional visible, uv, and ir optics. Recent work in Britain on x-ray optics (applied to molecular biology), on scanning electron microscopy, and in radioastronomy (discovery of pulsars) is mentioned. In the optics of the visible and ir there is an increasing interest in over-all systems design. .The formation of large industrial units capable of carrying through major design program, requiring advanced mechanical and electronic design associated with new lens systems, is welcomed.

Design and construction of a cost-efficient Arduino-based mirror galvanometer system for scanning optical microscopy

NASA Astrophysics Data System (ADS)

Hsu, Jen-Feng; Dhingra, Shonali; D'Urso, Brian

2017-01-01

Mirror galvanometer systems (galvos) are commonly employed in research and commercial applications in areas involving laser imaging, laser machining, laser-light shows, and others. Here, we present a robust, moderate-speed, and cost-efficient home-built galvo system. The mechanical part of this design consists of one mirror, which is tilted around two axes with multiple surface transducers. We demonstrate the ability of this galvo by scanning the mirror using a computer, via a custom driver circuit. The performance of the galvo, including scan range, noise, linearity, and scan speed, is characterized. As an application, we show that this galvo system can be used in a confocal scanning microscopy system.

Transfer function characteristics of super resolving systems

NASA Technical Reports Server (NTRS)

Milster, Tom D.; Curtis, Craig H.

1992-01-01

Signal quality in an optical storage device greatly depends on the optical system transfer function used to write and read data patterns. The problem is similar to analysis of scanning optical microscopes. Hopkins and Braat have analyzed write-once-read-many (WORM) optical data storage devices. Herein, transfer function analysis of magnetooptic (MO) data storage devices is discussed with respect to improving transfer-function characteristics. Several authors have described improving the transfer function as super resolution. However, none have thoroughly analyzed the MO optical system and effects of the medium. Both the optical system transfer function and effects of the medium of this development are discussed.

Holographic Optical Elements as Scanning Lidar Telescopes

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.

2005-01-01

We have developed and investigated the use of holographic optical elements (HOEs) and holographic transmission gratings for scanning lidar telescopes. For example, rotating a flat HOE in its own plane with the focal spot on the rotation axis makes a very simple and compact conical scanning telescope. We developed and tested transmission and reflection HOEs for use at the first three harmonic wavelengths of Nd:YAG lasers. The diffraction efficiency, diffraction angle, focal length, focal spot size and optical losses were measured for several HOEs and holographic gratings, and found to be suitable for use as lidar receiver telescopes, and in many cases could also serve as the final collimating and beam steering optic for the laser transmitter. Two lidar systems based on this technology have been designed, built, and successfully tested in atmospheric science applications. This technology will enable future spaceborne lidar missions by significantly lowering the size, weight, power requirement and cost of a large aperture, narrow field of view scanning telescope.

Illumination system design for a three-aspherical-mirror projection camera for extreme-ultraviolet lithography.

PubMed

Li, Y; Kinoshita, H; Watanabe, T; Irie, S; Shirayone, S; Okazaki, S

2000-07-01

A scanning critical illumination system is designed to couple a synchrotron radiation source to a three-aspherical-mirror imaging system for extreme ultraviolet lithography. A static illumination area of H x V = 8 mm x 3 mm (where H is horizontal and V is vertical) can be obtained. Uniform intensity distribution and a large ring field of H x V = 150 mm x 3 mm can be achieved by scanning of the mirror of the condenser. The coherence factor (sigma) of this illumination system is approximately 0.6, with the same beam divergence in both the horizontal and the vertical directions. We describe the performance of the imaging optics at sigma = 0.6 to confirm that the illumination optics can meet the requirements for three-aspherical-mirror imaging optics with a feature size of 0.06 microm.

Tip/tilt-compensated through-focus scanning optical microscopy

NASA Astrophysics Data System (ADS)

Lee, Jun Ho; Park, Jun Hyung; Jeong, Dohwan; Shin, Eun Ji; Park, Chris

2016-11-01

Through-Focus Optical Microscopy (TSOM), with nanometer scale lateral and vertical sensitivity matching those of scanning electron microscopy, has been demonstrated to be utilized for 3D inspection and metrology. There have been sensitivity and instability issues in acquiring through-focus images because TSOM 3D information is indirectly extracted by differentiating a target TSOM image from reference TSOM images. This paper first reports on the optical axis instability that occurs during the scanning process of TSOM when implemented in an existing patterned wafer inspection tool by moving the wafer plane; this is followed by quantitative confirmation of the optical/mechanical instability using a new TSOM tool on an optical bench with a Shack-Hartmann wavefront sensor and a tip/tilt sensor. Then, this paper proposes two tip/tilt compensated TSOM optical acquisition methods that can be applied with adaptive optics. The first method simply adopts a tip/tilt mirror with a quad cell in a simple closed loop, while the second method adopts a highorder deformable mirror with a Shack-Hartmann sensor. The second method is able to correct high-order residual aberrations as well as to perform through-focus scanning without z-axis movement, while the first method is easier to implement in pre-existing wafer inspection systems with only minor modification.

An Automated Medical Information Management System (OpScan-MIMS) in a Clinical Setting

PubMed Central

Margolis, S.; Baker, T.G.; Ritchey, M.G.; Alterescu, S.; Friedman, C.

1981-01-01

This paper describes an automated medical information management system within a clinic setting. The system includes an optically scanned data entry system (OpScan), a generalized, interactive retrieval and storage software system(Medical Information Management System, MIMS) and the use of time-sharing. The system has the advantages of minimal hardware purchase and maintenance, rapid data entry and retrieval, user-created programs, no need for user knowledge of computer language or technology and is cost effective. The OpScan-MIMS system has been operational for approximately 16 months in a sexually transmitted disease clinic. The system's application to medical audit, quality assurance, clinic management and clinical training are demonstrated.

Integrated adaptive optics optical coherence tomography and adaptive optics scanning laser ophthalmoscope system for simultaneous cellular resolution in vivo retinal imaging

PubMed Central

Zawadzki, Robert J.; Jones, Steven M.; Pilli, Suman; Balderas-Mata, Sandra; Kim, Dae Yu; Olivier, Scot S.; Werner, John S.

2011-01-01

We describe an ultrahigh-resolution (UHR) retinal imaging system that combines adaptive optics Fourier-domain optical coherence tomography (AO-OCT) with an adaptive optics scanning laser ophthalmoscope (AO-SLO) to allow simultaneous data acquisition by the two modalities. The AO-SLO subsystem was integrated into the previously described AO-UHR OCT instrument with minimal changes to the latter. This was done in order to ensure optimal performance and image quality of the AO- UHR OCT. In this design both imaging modalities share most of the optical components including a common AO-subsystem and vertical scanner. One of the benefits of combining Fd-OCT with SLO includes automatic co-registration between two acquisition channels for direct comparison between retinal structures imaged by both modalities (e.g., photoreceptor mosaics or microvasculature maps). Because of differences in the detection scheme of the two systems, this dual imaging modality instrument can provide insight into retinal morphology and potentially function, that could not be accessed easily by a single system. In this paper we describe details of the components and parameters of the combined instrument, including incorporation of a novel membrane magnetic deformable mirror with increased stroke and actuator count used as a single wavefront corrector. We also discuss laser safety calculations for this multimodal system. Finally, retinal images acquired in vivo with this system are presented. PMID:21698028

IMRT verification using a radiochromic/optical-CT dosimetry system

NASA Astrophysics Data System (ADS)

Oldham, Mark; Guo, Pengyi; Gluckman, Gary; Adamovics, John

2006-12-01

This work represents our first experiences relating to IMRT verification using a relatively new 3D dosimetry system consisting of a PRESAGETM dosimeter (Heuris Inc, Pharma LLC) and an optical-CT scanning system (OCTOPUSTM TM MGS Inc). This work builds in a step-wise manner on prior work in our lab.

MEMS-based non-rotatory circumferential scanning optical probe for endoscopic optical coherence tomography

NASA Astrophysics Data System (ADS)

Xu, Yingshun; Singh, Janak; Siang, Teo Hui; Ramakrishna, Kotlanka; Premchandran, C. S.; Sheng, Chen Wei; Kuan, Chuah Tong; Chen, Nanguang; Olivo, Malini C.; Sheppard, Colin J. R.

2007-07-01

In this paper, we present a non-rotatory circumferential scanning optical probe integrated with a MEMS scanner for in vivo endoscopic optical coherence tomography (OCT). OCT is an emerging optical imaging technique that allows high resolution cross-sectional imaging of tissue microstructure. To extend its usage to endoscopic applications, a miniaturized optical probe based on Microelectromechanical Systems (MEMS) fabrication techniques is currently desired. A 3D electrothermally actuated micromirror realized using micromachining single crystal silicon (SCS) process highlights its very large angular deflection, about 45 degree, with low driving voltage for safety consideration. The micromirror is integrated with a GRIN lens into a waterproof package which is compatible with requirements for minimally invasive endoscopic procedures. To implement circumferential scanning substantially for diagnosis on certain pathological conditions, such as Barret's esophagus, the micromirror is mounted on 90 degree to optical axis of GRIN lens. 4 Bimorph actuators that are connected to the mirror on one end via supporting beams and springs are selected in this micromirror design. When actuators of the micromirror are driven by 4 channels of sinusoidal waveforms with 90 degree phase differences, beam focused by a GRIN is redirected out of the endoscope by 45 degree tilting mirror plate and achieve circumferential scanning pattern. This novel driving method making full use of very large angular deflection capability of our micromirror is totally different from previously developed or developing micromotor-like rotatory MEMS device for circumferential scanning.

Apparatus and Method for Elimination of Polarization-Induced Fading in Fiber-optic Sensor System

NASA Technical Reports Server (NTRS)

Chan, Hon Man (Inventor); Parker, Jr., Allen R. (Inventor)

2015-01-01

The invention is an apparatus and method of eliminating polarization-induced fading in interferometric fiber-optic sensor system having a wavelength-swept laser optical signal. The interferometric return signal from the sensor arms are combined and provided to a multi-optical path detector assembly and ultimately to a data acquisition and processing unit by way of a switch that is time synchronized with the laser scan sweep cycle.

Birefringence measurement of retinal nerve fiber layer using polarization-sensitive spectral domain optical coherence tomography with Jones matrix based analysis

NASA Astrophysics Data System (ADS)

Yamanari, Masahiro; Miura, Masahiro; Makita, Shuichi; Yatagai, Toyohiko; Yasuno, Yoshiaki

2007-02-01

Birefringence of retinal nerve fiber layer is measured by polarization-sensitive spectral domain optical coherence tomography using the B-scan-oriented polarization modulation method. Birefringence of the optical fiber and the cornea is compensated by Jones matrix based analysis. Three-dimensional phase retardation map around the optic nerve head and en-face phase retardation map of the retinal nerve fiber layer are shown. Unlike scanning laser polarimetry, our system can measure the phase retardation quantitatively without using bow-tie pattern of the birefringence in the macular region, which enables diagnosis of glaucoma even if the patients have macular disease.

Security enhancement of optical encryption based on biometric array keys

NASA Astrophysics Data System (ADS)

Yan, Aimin; Wei, Yang; Zhang, Jingtao

2018-07-01

A novel optical image encryption method is proposed by using Dammann grating and biometric array keys. Dammann grating is utilized to create a 2D finite uniform-intensity spot array. In encryption, a fingerprint array is used as private encryption keys. An original image can be encrypted by a scanning Fresnel zone plate array. Encrypted signals are processed by an optical coherent heterodyne detection system. Biometric array keys and optical scanning cryptography are integrated with each other to enhance information security greatly. Numerical simulations are performed to demonstrate the feasibility and validity of this method. Analyses on key sensitivity and the resistance against to possible attacks are provided.

Re-evaluation of differential phase contrast (DPC) in a scanning laser microscope using a split detector as an alternative to differential interference contrast (DIC) optics.

PubMed

Amos, W B; Reichelt, S; Cattermole, D M; Laufer, J

2003-05-01

In this paper, differential phase imaging (DPC) with transmitted light is implemented by adding a suitable detection system to a standard commercially available scanning confocal microscope. DPC, a long-established method in scanning optical microscopy, depends on detecting the intensity difference between opposite halves or quadrants of a split photodiode detector placed in an aperture plane. Here, DPC is compared with scanned differential interference contrast (DIC) using a variety of biological specimens and objective lenses of high numerical aperture. While DPC and DIC images are generally similar, DPC seems to have a greater depth of field. DPC has several advantages over DIC. These include low cost (no polarizing or strain-free optics are required), absence of a double scanning spot, electronically variable direction of shading and the ability to image specimens in plastic dishes where birefringence prevents the use of DIC. DPC is also here found to need 20 times less laser power at the specimen than DIC.

Grating-based real-time smart optics for biomedicine and communications

NASA Astrophysics Data System (ADS)

Yaqoob, Zahid

Novel photonic systems are proposed and experimentally validated using active as well as passive wavelength dispersive optical devices in unique fashions to solve important system level application problems in biomedicine and laser communications. Specifically for the first time are proposed, high dynamic range variable optical attenuators (VOAs) using bulk acousto-optics (AO). These AO-based architectures have excellent characteristics such as high laser damage threshold (e.g., 1 Watt CW laser power operations), large (e.g., >40 dB) dynamic range, and microsecond domain attenuation setting speed. The demonstrated architectures show potentials for compact, low static insertion loss, and low power VOA designs for wavelength division multiplexed (WDM) fiber-optic communication networks and high speed photonic signal processing for optical and radio frequency (RF) radar and electronic warfare (EW). Acoustic diffraction of light in isotropic media has been manipulated to design and demonstrate on a proof-of-principle basis, the first bulk AO-based optical coherence tomography (OCT) system for high-resolution sub-surface tissue diagnostics. As opposed to the current OCT systems that use mechanical means to generate optical delays, both free-space as well as fiber-optic AO-based OCT systems utilize unique electronically-controlled acousto-optically switched no-moving parts optical delay lines and therefore promise microsecond speed OCT data acquisition rates. The proposed OCT systems also feature high (e.g., >100 MHz) intermediate frequency for low 1/f noise heterodyne detection. For the first time, two agile laser beam steering schemes that are members of a new beam steering technology known as Multiplexed-Optical Scanner Technology (MOST) are theoretically investigated and experimentally demonstrated. The new scanner technologies are based on wavelength and space manipulations and possess remarkable features such as a no-moving parts fast (e.g., microseconds domain or less) beam switching speed option, large (e.g., several centimeters) scanner apertures for high-resolution scans, and large (e.g., >10°) angular scans in more than one dimensions. These incredible features make these scanners excellent candidates for high-end applications. Specifically discussed and experimentally analyzed for the first time are novel MOST-based systems for agile free-space lasercom links, internal and external cavity scanning biomedical probes, and high-speed optical data handling such as barcode scanners. In addition, a novel low sidelobe wavelength selection filter based on a single bulk crystal acousto-optic tunable filter device is theoretically analyzed and experimentally demonstrated showing its versatility as a scanner control fiber-optic component for interfacing with the proposed wavelength based optical scanners. In conclusion, this thesis has shown how powerful photonic systems can be realized via novel architectures using active and passive wavelength sensitive optics leading to advanced solutions for the biomedical and laser communications research communities.

Analog signal processing for optical coherence imaging systems

NASA Astrophysics Data System (ADS)

Xu, Wei

Optical coherence tomography (OCT) and optical coherence microscopy (OCM) are non-invasive optical coherence imaging techniques, which enable micron-scale resolution, depth resolved imaging capability. Both OCT and OCM are based on Michelson interferometer theory. They are widely used in ophthalmology, gastroenterology and dermatology, because of their high resolution, safety and low cost. OCT creates cross sectional images whereas OCM obtains en face images. In this dissertation, the design and development of three increasingly complicated analog signal processing (ASP) solutions for optical coherence imaging are presented. The first ASP solution was implemented for a time domain OCT system with a Rapid Scanning Optical Delay line (RSOD)-based optical signal modulation and logarithmic amplifier (Log amp) based demodulation. This OCT system can acquire up to 1600 A-scans per second. The measured dynamic range is 106dB at 200A-scan per second. This OCT signal processing electronics includes an off-the-shelf filter box with a Log amp circuit implemented on a PCB board. The second ASP solution was developed for an OCM system with synchronized modulation and demodulation and compensation for interferometer phase drift. This OCM acquired micron-scale resolution, high dynamic range images at acquisition speeds up to 45,000 pixels/second. This OCM ASP solution is fully custom designed on a perforated circuit board. The third ASP solution was implemented on a single 2.2 mm x 2.2 mm complementary metal oxide semiconductor (CMOS) chip. This design is expandable to a multiple channel OCT system. A single on-chip CMOS photodetector and ASP channel was used for coherent demodulation in a time domain OCT system. Cross-sectional images were acquired with a dynamic range of 76dB (limited by photodetector responsivity). When incorporated with a bump-bonded InGaAs photodiode with higher responsivity, the expected dynamic range is close to 100dB.

Optical scanning apparatus for indicia imprinted about a cylindrical axis

DOEpatents

Villarreal, Richard A.

1987-01-01

An optical scanner employed in a radioactive environment for reading indicia imprinted about a cylindrical surface of an article by means of an optical system including metallic reflective and mirror surfaces resistant to degradation and discoloration otherwise imparted to glass surfaces exposed to radiation.

Advanced multiphoton methods for in vitro and in vivo functional imaging of mouse retinal neurons (Conference Presentation)

NASA Astrophysics Data System (ADS)

Cohen, Noam; Schejter, Adi; Farah, Nairouz; Shoham, Shy

2016-03-01

Studying the responses of retinal ganglion cell (RGC) populations has major significance in vision research. Multiphoton imaging of optogenetic probes has recently become the leading approach for visualizing neural populations and has specific advantages for imaging retinal activity during visual stimulation, because it leads to reduced direct photoreceptor excitation. However, multiphoton retinal activity imaging is not straightforward: point-by-point scanning leads to repeated neural excitation while optical access through the rodent eye in vivo has proven highly challenging. Here, we present two enabling optical designs for multiphoton imaging of responses to visual stimuli in mouse retinas expressing calcium indicators. First, we present an imaging solution based on Scanning Line Temporal Focusing (SLITE) for rapidly imaging neuronal activity in vitro. In this design, we scan a temporally focused line rather than a point, increasing the scan speed and reducing the impact of repeated excitation, while maintaining high optical sectioning. Second, we present the first in vivo demonstration of two-photon imaging of RGC activity in the mouse retina. To obtain these cellular resolution recordings we integrated an illumination path into a correction-free imaging system designed using an optical model of the mouse eye. This system can image at multiple depths using an electronically tunable lens integrated into its optical path. The new optical designs presented here overcome a number of outstanding obstacles, allowing the study of rapid calcium- and potentially even voltage-indicator signals both in vitro and in vivo, thereby bringing us a step closer toward distributed monitoring of action potentials.

Compact multi-bounce projection system for extreme ultraviolet projection lithography

DOEpatents

Hudyma, Russell M.

2002-01-01

An optical system compatible with short wavelength (extreme ultraviolet) radiation comprising four optical elements providing five reflective surfaces for projecting a mask image onto a substrate. The five optical surfaces are characterized in order from object to image as concave, convex, concave, convex and concave mirrors. The second and fourth reflective surfaces are part of the same optical element. The optical system is particularly suited for ring field step and scan lithography methods. The invention uses aspheric mirrors to minimize static distortion and balance the static distortion across the ring field width, which effectively minimizes dynamic distortion.

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.

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.

Design and Development of an Optical Path Difference Scan Mechanism for Fourier Transform Spectrometers using High Displacement RAINBOW Actuators

NASA Technical Reports Server (NTRS)

Wise, Stephanie A.; Hardy, Robin C.; Dausch, David E.

1997-01-01

A new piezoelectric drive mechanism has been developed for optical translation in space-based spectrometer systems. The mechanism utilizes a stack of RAINBOW high displacement piezoelectric actuators to move optical components weighing less than 250 grams through a one centimeter travel. The mechanism uses the direct motion of the piezoelectric devices, stacked such that the displacement of the individual RAINBOW actuators is additive. A prototype device has been built which utilizes 21 RAINBOWs to accomplish the necessary travel. The mechanism weighs approximately 0.6 kilograms and uses less than 2 Watts of power at a scanning frequency of 0.5 Hertz, significantly less power than that required by state-of-the-art motor systems.

Multiplane optical microscope

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

Li, Tongcang; Ota, Sadao; Kim, Jeongmin

This disclosure provides systems, methods, and apparatus related to optical microscopy. In one aspect, an apparatus includes a sample holder, a first objective lens, a plurality of optical components, a second objective lens, and a mirror. The apparatus may directly image a cross-section of a sample oblique to or parallel to the optical axis of the first objective lens, without scanning.

Highly sensitive mode mapping of whispering-gallery modes by scanning thermocouple-probe microscopy.

PubMed

Klein, Angela E; Schmidt, Carsten; Liebsch, Mattes; Janunts, Norik; Dobynde, Mikhail; Tünnermann, Andreas; Pertsch, Thomas

2014-03-01

We propose a method for mapping optical near-fields with the help of a thermocouple scanning-probe microscope tip. As the tip scans the sample surface, its apex is heated by light absorption, generating a thermovoltage. The thermovoltage map represents the intensity distribution of light at the sample surface. The measurement technique has been employed to map optical whispering-gallery modes in fused silica microdisk resonators operating at near-infrared wavelengths. The method could potentially be employed for near-field imaging of a variety of systems in the near-infrared and visible spectral range.

Video-rate scanning two-photon excitation fluorescence microscopy and ratio imaging with cameleons.

PubMed Central

Fan, G Y; Fujisaki, H; Miyawaki, A; Tsay, R K; Tsien, R Y; Ellisman, M H

1999-01-01

A video-rate (30 frames/s) scanning two-photon excitation microscope has been successfully tested. The microscope, based on a Nikon RCM 8000, incorporates a femtosecond pulsed laser with wavelength tunable from 690 to 1050 nm, prechirper optics for laser pulse-width compression, resonant galvanometer for video-rate point scanning, and a pair of nonconfocal detectors for fast emission ratioing. An increase in fluorescent emission of 1.75-fold is consistently obtained with the use of the prechirper optics. The nonconfocal detectors provide another 2.25-fold increase in detection efficiency. Ratio imaging and optical sectioning can therefore be performed more efficiently without confocal optics. Faster frame rates, at 60, 120, and 240 frames/s, can be achieved with proportionally reduced scan lines per frame. Useful two-photon images can be acquired at video rate with a laser power as low as 2.7 mW at specimen with the genetically modified green fluorescent proteins. Preliminary results obtained using this system confirm that the yellow "cameleons" exhibit similar optical properties as under one-photon excitation conditions. Dynamic two-photon images of cardiac myocytes and ratio images of yellow cameleon-2.1, -3.1, and -3.1nu are also presented. PMID:10233058

Inspection of float glass using a novel retroreflective laser scanning system

NASA Astrophysics Data System (ADS)

Holmes, Jonathan D.

1997-07-01

Since 1988, Image Automation has marketed a float glass inspection system using a novel retro-reflective laser scanning system. The (patented) instrument scans a laser beam by use of a polygon through the glass onto a retro-reflective screen, and collects the retro-reflected light off the polygon, such that a stationary image of the moving spot on the screen is produced. The spot image is then analyzed for optical effects introduced by defects within the glass, which typically distort and attenuate the scanned laser beam, by use of suitable detectors. The inspection system processing provides output of defect size, shape and severity, to the factory network for use in rejection or sorting of glass plates to the end customer. This paper briefly describes the principles of operation, the system architecture, and limitations to sensitivity and measurement repeatability. New instruments based on the retro-reflective scanning method have recently been developed. The principles and implementation are described. They include: (1) Simultaneous detection of defects within the glass and defects in a mirror coating on the glass surface using polarized light. (2) A novel distortion detector for very dark glass. (3) Measurement of optical quality (flatness/refractive homogeneity) of the glass using a position sensitive detector.

Image Quality Analysis and Optical Performance Requirement for Micromirror-Based Lissajous Scanning Displays

PubMed Central

Du, Weiqi; Zhang, Gaofei; Ye, Liangchen

2016-01-01

Micromirror-based scanning displays have been the focus of a variety of applications. Lissajous scanning displays have advantages in terms of power consumption; however, the image quality is not good enough. The main reason for this is the varying size and the contrast ratio of pixels at different positions of the image. In this paper, the Lissajous scanning trajectory is analyzed and a new method based on the diamond pixel is introduced to Lissajous displays. The optical performance of micromirrors is discussed. A display system demonstrator is built, and tests of resolution and contrast ratio are conducted. The test results show that the new Lissajous scanning method can be used in displays by using diamond pixels and image quality remains stable at different positions. PMID:27187390

Image Quality Analysis and Optical Performance Requirement for Micromirror-Based Lissajous Scanning Displays.

PubMed

Du, Weiqi; Zhang, Gaofei; Ye, Liangchen

2016-05-11

Micromirror-based scanning displays have been the focus of a variety of applications. Lissajous scanning displays have advantages in terms of power consumption; however, the image quality is not good enough. The main reason for this is the varying size and the contrast ratio of pixels at different positions of the image. In this paper, the Lissajous scanning trajectory is analyzed and a new method based on the diamond pixel is introduced to Lissajous displays. The optical performance of micromirrors is discussed. A display system demonstrator is built, and tests of resolution and contrast ratio are conducted. The test results show that the new Lissajous scanning method can be used in displays by using diamond pixels and image quality remains stable at different positions.

A new adaptive light beam focusing principle for scanning light stimulation systems.

PubMed

Bitzer, L A; Meseth, M; Benson, N; Schmechel, R

2013-02-01

In this article a novel principle to achieve optimal focusing conditions or rather the smallest possible beam diameter for scanning light stimulation systems is presented. It is based on the following methodology: First, a reference point on a camera sensor is introduced where optimal focusing conditions are adjusted and the distance between the light focusing optic and the reference point is determined using a laser displacement sensor. In a second step, this displacement sensor is used to map the topography of the sample under investigation. Finally, the actual measurement is conducted, using optimal focusing conditions in each measurement point at the sample surface, that are determined by the height difference between camera sensor and the sample topography. This principle is independent of the measurement values, the optical or electrical properties of the sample, the used light source, or the selected wavelength. Furthermore, the samples can be tilted, rough, bent, or of different surface materials. In the following the principle is implemented using an optical beam induced current system, but basically it can be applied to any other scanning light stimulation system. Measurements to demonstrate its operation are shown, using a polycrystalline silicon solar cell.

Tuning of successively scanned two monolithic Vernier-tuned lasers and selective data sampling in optical comb swept source optical coherence tomography

PubMed Central

Choi, Dong-hak; Yoshimura, Reiko; Ohbayashi, Kohji

2013-01-01

Monolithic Vernier tuned super-structure grating distributed Bragg reflector (SSG-DBR) lasers are expected to become one of the most promising sources for swept source optical coherence tomography (SS-OCT) with a long coherence length, reduced sensitivity roll-off, and potential capability for a very fast A-scan rate. However, previous implementations of the lasers suffer from four main problems: 1) frequencies deviate from the targeted values when scanned, 2) large amounts of noise appear associated with abrupt changes in injection currents, 3) optically aliased noise appears due to a long coherence length, and 4) the narrow wavelength coverage of a single chip limits resolution. We have developed a method of dynamical frequency tuning, a method of selective data sampling to eliminate current switching noise, an interferometer to reduce aliased noise, and an excess-noise-free connection of two serially scanned lasers to enhance resolution to solve these problems. An optical frequency comb SS-OCT system was achieved with a sensitivity of 124 dB and a dynamic range of 55-72 dB that depended on the depth at an A-scan rate of 3.1 kHz with a resolution of 15 μm by discretely scanning two SSG-DBR lasers, i.e., L-band (1.560-1.599 μm) and UL-band (1.598-1.640 μm). A few OCT images with excellent image penetration depth were obtained. PMID:24409394

Laser scanning endoscope for diagnostic medicine

NASA Astrophysics Data System (ADS)

Ouimette, Donald R.; Nudelman, Sol; Spackman, Thomas; Zaccheo, Scott

1990-07-01

A new type of endoscope is being developed which utilizes an optical raster scanning system for imaging through an endoscope. The optical raster scanner utilizes a high speed, multifaceted, rotating polygon mirror system for horizontal deflection, and a slower speed galvanometer driven mirror as the vertical deflection system. When used in combination, the optical raster scanner traces out a raster similar to an electron beam raster used in television systems. This flying spot of light can then be detected by various types of photosensitive detectors to generate a video image of the surface or scene being illuminated by the scanning beam. The optical raster scanner has been coupled to an endoscope. The raster is projected down the endoscope, thereby illuminating the object to be imaged at the distal end of the endoscope. Elemental photodetectors are placed at the distal or proximal end of the endoscope to detect the reflected illumination from the flying spot of light. This time sequenced signal is captured by an image processor for display and processing. This technique offers the possibility for very small diameter endoscopes since illumination channel requirements are eliminated. Using various lasers, very specific spectral selectivity can be achieved to optimum contrast of specific lesions of interest. Using several laser lines, or a white light source, with detectors of specific spectral response, multiple spectrally selected images can be acquired simultaneously. The potential for co-linear therapy delivery while imaging is also possible.

Combined hostile fire and optics detection

NASA Astrophysics Data System (ADS)

Brännlund, Carl; Tidström, Jonas; Henriksson, Markus; Sjöqvist, Lars

2013-10-01

Snipers and other optically guided weapon systems are serious threats in military operations. We have studied a SWIR (Short Wave Infrared) camera-based system with capability to detect and locate snipers both before and after shot over a large field-of-view. The high frame rate SWIR-camera allows resolution of the temporal profile of muzzle flashes which is the infrared signature associated with the ejection of the bullet from the rifle. The capability to detect and discriminate sniper muzzle flashes with this system has been verified by FOI in earlier studies. In this work we have extended the system by adding a laser channel for optics detection. A laser diode with slit-shaped beam profile is scanned over the camera field-of-view to detect retro reflection from optical sights. The optics detection system has been tested at various distances up to 1.15 km showing the feasibility to detect rifle scopes in full daylight. The high speed camera gives the possibility to discriminate false alarms by analyzing the temporal data. The intensity variation, caused by atmospheric turbulence, enables discrimination of small sights from larger reflectors due to aperture averaging, although the targets only cover a single pixel. It is shown that optics detection can be integrated in combination with muzzle flash detection by adding a scanning rectangular laser slit. The overall optics detection capability by continuous surveillance of a relatively large field-of-view looks promising. This type of multifunctional system may become an important tool to detect snipers before and after shot.

Design and development of a fiber optic TDI CCD-based slot-scan digital mammography system

NASA Astrophysics Data System (ADS)

Toker, Emre; Piccaro, Michele F.

1993-12-01

We previously reported on the development, design, and clinical evaluation of a CCD-based, high performance, filmless imaging system for stereotactic needle biopsy procedures in mammography. The MammoVision system has a limited imaging area of 50 mm X 50 mm, since it is designed specifically for breast biopsy applications. We are currently developing a new filmless imaging system designed to cover the 18 cm X 24 cm imaging area required for screening and diagnostic mammography. The diagnostic mammography system is based on four 1100 X 330 pixel format, full-frame, scientific grade, front illuminated, MPP mode CCDs, with 24 micrometers X 24 micrometers square pixels Each CCD is coupled to an x-ray intensifying screen via a 1.7:1 fiber optic reducer. The detector assembly (180 mm long and 13.5 mm wide) is scanned across the patient's breast synchronously with the x-ray source, with the CCDs operated in time-delay integration (TDI) mode. The total scan time is 4.0 seconds.

Full area covered 3D profile measurement of special-shaped optics based on a new prototype non-contact profiler

NASA Astrophysics Data System (ADS)

Du, Hui-Lin; Zhou, Zhao-Zhong; Sun, Ze-Qing; Ju, Bing-Feng; Xu, Shaoning; Sun, Anyu

2017-06-01

A new prototype non-contact profiler based on surface tracking has been specially developed. Surface tracking is carried out by a specially designed dual stage probe system with the aid of a four-Degree Of Freedom high-precision motion platform. The dual stage probe system keeps a short-range optical probe constantly tracking the surface by a self-developed voice coil motor servo, by which a wide measuring range of up to 10 mm is realized. The system performance evaluation including resolution, repeatability, and scanning speed proved the good capability of the new prototype non-contact profiler. To realize a full area covered 3D profile measurement of special-shaped optics within one scanning procedure, a signal intensity monitor integrated in the surface tracking controller is specially developed. In the experiment, a snip-single-corner-rectangular-shaped freeform surface was successfully measured over full area by the new non-contact profiler. This work provides an effective solution for 3D profile measurement of special-shaped optical surfaces over full reflecting area. Experimental results demonstrate that the proposed measuring system is of great significance in quality evaluation of optical surfaces.

Full area covered 3D profile measurement of special-shaped optics based on a new prototype non-contact profiler.

PubMed

Du, Hui-Lin; Zhou, Zhao-Zhong; Sun, Ze-Qing; Ju, Bing-Feng; Xu, Shaoning; Sun, Anyu

2017-06-01

A new prototype non-contact profiler based on surface tracking has been specially developed. Surface tracking is carried out by a specially designed dual stage probe system with the aid of a four-Degree Of Freedom high-precision motion platform. The dual stage probe system keeps a short-range optical probe constantly tracking the surface by a self-developed voice coil motor servo, by which a wide measuring range of up to 10 mm is realized. The system performance evaluation including resolution, repeatability, and scanning speed proved the good capability of the new prototype non-contact profiler. To realize a full area covered 3D profile measurement of special-shaped optics within one scanning procedure, a signal intensity monitor integrated in the surface tracking controller is specially developed. In the experiment, a snip-single-corner-rectangular-shaped freeform surface was successfully measured over full area by the new non-contact profiler. This work provides an effective solution for 3D profile measurement of special-shaped optical surfaces over full reflecting area. Experimental results demonstrate that the proposed measuring system is of great significance in quality evaluation of optical surfaces.

TOWARD QUANTITATIVE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY: Visualizing Blood Flow Speeds in Ocular Pathology Using Variable Interscan Time Analysis.

PubMed

Ploner, Stefan B; Moult, Eric M; Choi, WooJhon; Waheed, Nadia K; Lee, ByungKun; Novais, Eduardo A; Cole, Emily D; Potsaid, Benjamin; Husvogt, Lennart; Schottenhamml, Julia; Maier, Andreas; Rosenfeld, Philip J; Duker, Jay S; Hornegger, Joachim; Fujimoto, James G

2016-12-01

Currently available optical coherence tomography angiography systems provide information about blood flux but only limited information about blood flow speed. The authors develop a method for mapping the previously proposed variable interscan time analysis (VISTA) algorithm into a color display that encodes relative blood flow speed. Optical coherence tomography angiography was performed with a 1,050 nm, 400 kHz A-scan rate, swept source optical coherence tomography system using a 5 repeated B-scan protocol. Variable interscan time analysis was used to compute the optical coherence tomography angiography signal from B-scan pairs having 1.5 millisecond and 3.0 milliseconds interscan times. The resulting VISTA data were then mapped to a color space for display. The authors evaluated the VISTA visualization algorithm in normal eyes (n = 2), nonproliferative diabetic retinopathy eyes (n = 6), proliferative diabetic retinopathy eyes (n = 3), geographic atrophy eyes (n = 4), and exudative age-related macular degeneration eyes (n = 2). All eyes showed blood flow speed variations, and all eyes with pathology showed abnormal blood flow speeds compared with controls. The authors developed a novel method for mapping VISTA into a color display, allowing visualization of relative blood flow speeds. The method was found useful, in a small case series, for visualizing blood flow speeds in a variety of ocular diseases and serves as a step toward quantitative optical coherence tomography angiography.

Precision Targeting With a Tracking Adaptive Optics Scanning Laser Ophthalmoscope

DTIC Science & Technology

2006-01-01

automatic high- resolution mosaic generation, and automatic blink detection and tracking re-lock were also tested. The system has the potential to become an...structures can lead to earlier detection of retinal diseases such as age-related macular degeneration (AMD) and diabetic retinopathy (DR). Combined...optics systems sense perturbations in the detected wave-front and apply corrections to an optical element that flatten the wave-front and allow near

Photothermal camera port accessory for microscopic thermal diffusivity imaging

NASA Astrophysics Data System (ADS)

Escola, Facundo Zaldívar; Kunik, Darío; Mingolo, Nelly; Martínez, Oscar Eduardo

2016-06-01

The design of a scanning photothermal accessory is presented, which can be attached to the camera port of commercial microscopes to measure thermal diffusivity maps with micrometer resolution. The device is based on the thermal expansion recovery technique, which measures the defocusing of a probe beam due to the curvature induced by the local heat delivered by a focused pump beam. The beam delivery and collecting optics are built using optical fiber technology, resulting in a robust optical system that provides collinear pump and probe beams without any alignment adjustment necessary. The quasiconfocal configuration for the signal collection using the same optical fiber sets very restrictive conditions on the positioning and alignment of the optical components of the scanning unit, and a detailed discussion of the design equations is presented. The alignment procedure is carefully described, resulting in a system so robust and stable that no further alignment is necessary for the day-to-day use, becoming a tool that can be used for routine quality control, operated by a trained technician.

Improvement of highly sensitive lidar with a thumb-sized sensor-head built using an optical fiber preamplifier

NASA Astrophysics Data System (ADS)

Inoue, Daisuke; Ichikawa, Tadashi; Matsubara, Hiroyuki; Mao, Xueon; Maeda, Mitsutoshi; Nagashima, Chie; Kagami, Manabu

2012-06-01

We have developed a LIDAR system with a sensor head which, although it includes a scanning mechanism, is less than 20 cc in size. The system is not only small, but is also highly sensitive. Our LIDAR system is based on time-of-flight measurements, and incorporates an optical fiber. The main feature of our system is the utilization of optical amplifiers for both the transmitter and the receiver, and the optical amplifiers enable us to exceed the detection limit set by thermal noise. In conventional LIDAR systems the detection limit is determined by the thermal noise, because the avalanche photo-diodes (APD) and trans-impedance amplifiers (TIA) that they use detect the received signals directly. In the case of our LIDAR system, the received signal is amplified by an optical fiber amplifier before reaching the photo diode and the TIA. Therefore, our LIDAR system boosts the signal level before the weak incoming signal is depleted by thermal noise. There are conditions under which the noise figure for the combination of an optical fiber amplifier and a photo diode is superior to the noise figure for an avalanche photo diode. We optimized the gains of the optical fiber amplifier and the TIA in our LIDAR system such that it would be capable of detecting a single photon. As a result, the detection limit of our system is determined by shot noise. We have previously demonstrated optical pre-amplified LIDAR with a perfect co-axial optical system[1]. For this we used a variable optical attenuator to remove internal reflection from the transmission and receiving lenses. However, the optical attenuator had an insertion loss of 6dB which reduced the sensitivity of the LIDAR. We re-designed the optical system such that it was semi-co-axial and removed the variable optical attenuator. As a result, we succeeded in scanning up to a range of 80 m. This small and highly sensitive measurement technology shows great potential for use in LIDAR.

A system for simulating aerial or orbital TV observations of geographic patterns

NASA Technical Reports Server (NTRS)

Latham, J. P.

1972-01-01

A system which simulates observation of the earth surface by aerial or orbiting television devices has been developed. By projecting color slides of photographs taken by aircraft and orbiting sensors upon a rear screen system, and altering scale of projected image, screen position, or TV camera position, it is possible to simulate alternatives of altitude, or optical systems. By altering scan line patterns in COHU 3200 series camera from 525 to 945 scan lines, it is possible to study implications of scan line resolution upon the detection and analysis of geographic patterns observed by orbiting TV systems.

Quantifying the movement of multiple insects using an optical insect counter

USDA-ARS?s Scientific Manuscript database

An optical insect counter (OIC) was designed and tested. The new system integrated a line-scan camera and a vertical light sheet along with data collection and image processing software to count numbers of flying insects crossing a vertical plane defined by the light sheet. The system also allows ...

Method and systems for collecting data from multiple fields of view

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K. (Inventor)

2002-01-01

Systems and methods for processing light from multiple fields (48, 54, 55) of view without excessive machinery for scanning optical elements. In an exemplary embodiment of the invention, multiple holographic optical elements (41, 42, 43, 44, 45), integrated on a common film (4), diffract and project light from respective fields of view.

Optical scanning tests of complex CMOS microcircuits

NASA Technical Reports Server (NTRS)

Levy, M. E.; Erickson, J. J.

1977-01-01

The new test method was based on the use of a raster-scanned optical stimulus in combination with special electrical test procedures. The raster-scanned optical stimulus was provided by an optical spot scanner, an instrument that combines a scanning optical microscope with electronic instrumentation to process and display the electric photoresponse signal induced in a device that is being tested.

A large-scan-angle piezoelectric MEMS optical scanner actuated by a Nb-doped PZT thin film

NASA Astrophysics Data System (ADS)

Naono, Takayuki; Fujii, Takamichi; Esashi, Masayoshi; Tanaka, Shuji

2014-01-01

Resonant 1D microelectromechanical systems (MEMS) optical scanners actuated by piezoelectric unimorph actuators with a Nb-doped lead zirconate titanate (PNZT) thin film were developed for endoscopic optical coherence tomography (OCT) application. The MEMS scanners were designed as the resonance frequency was less than 125 Hz to obtain enough pixels per frame in OCT images. The device size was within 3.4 mm × 2.5 mm, which is compact enough to be installed in a side-imaging probe with 4 mm inner diameter. The fabrication process started with a silicon-on-insulator wafer, followed by PNZT deposition by the Rf sputtering and Si bulk micromachining process. The fabricated MEMS scanners showed maximum optical scan angles of 146° at 90 Hz, 148° at 124 Hz, 162° at 180 Hz, and 152° at 394 Hz at resonance in atmospheric pressure. Such wide scan angles were obtained by a drive voltage below 1.3 Vpp, ensuring intrinsic safety in in vivo uses. The scanner with the unpoled PNZT film showed three times as large a scan angle as that with a poled PZT films. A swept-source OCT system was constructed using the fabricated MEMS scanner, and cross-sectional images of a fingertip with image widths of 4.6 and 2.3 mm were acquired. In addition, a PNZT-based angle sensor was studied for feedback operation.

Development of optical surface-profiling instrumentation

NASA Astrophysics Data System (ADS)

Lin, Yao; Takacs, Peter Z.; Tsang, Thomas; Furenlid, Karen; Wang, Runwen

1992-12-01

A novel non-contact optical profiler described in this paper is designed and made for measuring the surface characteristics of optical parts. Measurements are based on a combination of an optical heterodyne technique and a precise phase measurement procedure without the need of a reference surface. A Zeeman-split He-Ne laser is employed as the light source which offers two common-path polarized beams. The frequency difference between the beams is 1.8 MHz. A special optical head is designed and fashioned as a beam splitter which contains a birefringent lens and an objective. The whole optical system is completely common- path. This allows the optical common-mode rejection technique to be applied in the system for minimizing the environmental effects in measurements such as air turbulence, vibrations and temperature variations. To keep the sample surface focused on the ordinary rays in the optical head, an astigmatic autofocus system is employed. A stepping micro-stepping system can move the optical head in the range of 25 mm with 0.1 micrometers resolution. A data acquisition system is made to control the auto-focus system, data receiving and analyses. This makes the measurement automatically while the sample is being scanned. The characteristics of the surface can be displayed on the computer screen. The theoretical and experimental analyses of the profiler are completed. The profiler measures samples with 1.1 angstroms height accuracy and 4 micrometers lateral resolution when a 40X objective is used in the optical head. The accuracy comparisons of the profiler with different objectives 5X, 10X, 20X, and 40X are shown in good agreement. The advantages of the present profiler are presented. Based on the autofocus system, the profiler optical system will be designed to mount on a large linear air-bearing slide, so that it is capable of scanning over a distance covering from 4 micrometers to 1 m.

Display system employing acousto-optic tunable filter

NASA Technical Reports Server (NTRS)

Lambert, James L. (Inventor)

1995-01-01

An acousto-optic tunable filter (AOTF) is employed to generate a display by driving the AOTF with a RF electrical signal comprising modulated red, green, and blue video scan line signals and scanning the AOTF with a linearly polarized, pulsed light beam, resulting in encoding of color video columns (scan lines) of an input video image into vertical columns of the AOTF output beam. The AOTF is illuminated periodically as each acoustically-encoded scan line fills the cell aperture of the AOTF. A polarizing beam splitter removes the unused first order beam component of the AOTF output and, if desired, overlays a real world scene on the output plane. Resolutions as high as 30,000 lines are possible, providing holographic display capability.

Display system employing acousto-optic tunable filter

NASA Technical Reports Server (NTRS)

Lambert, James L. (Inventor)

1993-01-01

An acousto-optic tunable filter (AOTF) is employed to generate a display by driving the AOTF with a RF electrical signal comprising modulated red, green, and blue video scan line signals and scanning the AOTF with a linearly polarized, pulsed light beam, resulting in encoding of color video columns (scan lines) of an input video image into vertical columns of the AOTF output beam. The AOTF is illuminated periodically as each acoustically-encoded scan line fills the cell aperture of the AOTF. A polarizing beam splitter removes the unused first order beam component of the AOTF output and, if desired, overlays a real world scene on the output plane. Resolutions as high as 30,000 lines are possible, providing holographic display capability.

Optical resolution photoacoustic microscopy using novel high-repetition-rate passively Q-switched microchip and fiber lasers.

PubMed

Shi, Wei; Kerr, Shaun; Utkin, Ilya; Ranasinghesagara, Janaka; Pan, Lei; Godwal, Yogesh; Zemp, Roger J; Fedosejevs, Robert

2010-01-01

Optical-resolution photoacoustic microscopy (OR-PAM) is a novel imaging technology for visualizing optically absorbing superficial structures in vivo with lateral spatial resolution determined by optical focusing rather than acoustic detection. Since scanning of the illumination spot is required, OR-PAM imaging speed is limited by both scanning speed and laser pulse repetition rate. Unfortunately, lasers with high repetition rates and suitable pulse durations and energies are not widely available and can be cost-prohibitive and bulky. We are developing compact, passively Q-switched fiber and microchip laser sources for this application. The properties of these lasers are discussed, and pulse repetition rates up to 100 kHz are demonstrated. OR-PAM imaging was conducted using a previously developed photoacoustic probe, which enabled flexible scanning of the focused output of the lasers. Phantom studies demonstrate the ability to image with lateral spatial resolution of 7±2 μm with the microchip laser system and 15±5 μm with the fiber laser system. We believe that the high pulse repetition rates and the potentially compact and fiber-coupled nature of these lasers will prove important for clinical imaging applications where real-time imaging performance is essential.

A high-resolution, confocal laser-scanning microscope and flash photolysis system for physiological studies.

PubMed

Parker, I; Callamaras, N; Wier, W G

1997-06-01

We describe the construction of a high-resolution confocal laser-scanning microscope, and illustrate its use for studying elementary Ca2+ signalling events in cells. An avalanche photodiode module and simple optical path provide a high efficiency system for detection of fluorescence signals, allowing use of a small confocal aperture giving near diffraction-limited spatial resolution (< 300 nm lateral and < 400 nm axial). When operated in line-scan mode, the maximum temporal resolution is 1 ms, and the associated computer software allows complete flexibility to record line-scans continuously for long (minutes) periods or to obtain any desired pixel resolution in x-y scans. An independent UV irradiation system permits simultaneous photolysis of caged compounds over either a uniform, wide field (arc lamp source) or at a tightly focussed spot (frequency-tripled Nd:YAG laser). The microscope thus provides a versatile tool for optical studies of dynamic cellular processes, as well as excellent resolution for morphological studies. The confocal scanner can be added to virtually any inverted microscope for a component cost that is only a small fraction of that of comparable commercial instruments, yet offers better performance and greater versatility.

In vivo endoscopic optical coherence tomography by use of a rotational microelectromechanical system probe

NASA Astrophysics Data System (ADS)

Tran, Peter H.; Mukai, David S.; Brenner, Matthew; Chen, Zhongping

2004-06-01

A novel endoscopic optical coherence tomography probe was designed and constructed with a 1.9-mm microelectromechanical system (MEMS) motor. The new MEMS endoscopic probe design eliminates the need to couple the rotational energy from the proximal to the distal end of the probe. Furthermore, the endoscopic probe's sheath and fiber have the advantages of having a much smaller diameter and being more flexible than traditional endoscopes since no reinforcement is needed to couple the rotational torque. At the distal end, a prism mounted on a micromotor deflects the light rays to create a transverse circular-scanning pathway. Because our MEMS scanner does not require the coupling of a rotational single-mode fiber, a high scanning speed is possible while eliminating unstable optical signals caused by nonuniform coupling.

Fiber optic Cerenkov radiation sensor system to estimate burn-up of spent fuel: characteristic evaluation of the system using Co-60 source

NASA Astrophysics Data System (ADS)

Shin, S. H.; Jang, K. W.; Jeon, D.; Hong, S.; Kim, S. G.; Sim, H. I.; Yoo, W. J.; Park, B. G.; Lee, B.

2013-09-01

Cerenkov radiation occurs when charged particles are moving faster than the speed of light in a transparent dielectric medium. In optical fibers, the Cerenkov light also can be generated due to their dielectric components. Accordingly, the radiation-induced light signals can be obtained using optical fibers without any scintillating material. In this study, to measure the intensities of Cerenkov radiation induced by gamma-rays, we have fabricated the fiber-optic Cerenkov radiation sensor system using silica optical fibers, plastic optical fibers, multi-anode photomultiplier tubes, and a scanning system. To characterize the Cerenkov radiation generated in optical fibers, the spectra of Cerenkov radiation generated in the silica and plastic optical fibers were measured. Also, the intensities of Cerenkov radiation induced by gamma-rays generated from a cylindrical Co-60 source with or without lead shielding were measured using the fiberoptic Cerenkov radiation sensor system.

A correlative optical microscopy and scanning electron microscopy approach to locating nanoparticles in brain tumors.

PubMed

Kempen, Paul J; Kircher, Moritz F; de la Zerda, Adam; Zavaleta, Cristina L; Jokerst, Jesse V; Mellinghoff, Ingo K; Gambhir, Sanjiv S; Sinclair, Robert

2015-01-01

The growing use of nanoparticles in biomedical applications, including cancer diagnosis and treatment, demands the capability to exactly locate them within complex biological systems. In this work a correlative optical and scanning electron microscopy technique was developed to locate and observe multi-modal gold core nanoparticle accumulation in brain tumor models. Entire brain sections from mice containing orthotopic brain tumors injected intravenously with nanoparticles were imaged using both optical microscopy to identify the brain tumor, and scanning electron microscopy to identify the individual nanoparticles. Gold-based nanoparticles were readily identified in the scanning electron microscope using backscattered electron imaging as bright spots against a darker background. This information was then correlated to determine the exact location of the nanoparticles within the brain tissue. The nanoparticles were located only in areas that contained tumor cells, and not in the surrounding healthy brain tissue. This correlative technique provides a powerful method to relate the macro- and micro-scale features visible in light microscopy with the nanoscale features resolvable in scanning electron microscopy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Design and experiment of spectrometer based on scanning micro-grating integrating with angle sensor

NASA Astrophysics Data System (ADS)

Biao, Luo; Wen, Zhi-yu

2014-01-01

A compact, low cost, high speed, non-destructive testing NIR (near infrared) spectrometer optical system based on MOEMS grating device is developed. The MOEMS grating works as the prismatic element and wavelength scanning element in our optical system. The MOEMS grating enables the design of compact grating spectrometers capable of acquiring full spectra using a single detector element. This MOEMS grating is driven by electromagnetic force and integrated with angle sensor which used to monitored deflection angle while the grating working. Comparing with the traditional spectral system, there is a new structure with a single detector and worked at high frequency. With the characteristics of MOEMS grating, the structure of the spectrometer system is proposed. After calculating the parameters of the optical path, ZEMAX optical software is used to simulate the system. According the ZEMAX output file of the 3D model, the prototype is designed by SolidWorks rapidly, fabricated. Designed for a wavelength range between 800 nm and 1500 nm, the spectrometer optical system features a spectral resolution of 16 nm with the volume of 97 mm × 81.7 mm × 81 mm. For the purpose of reduce modulated effect of sinusoidal rotation, spectral intensity of the different wavelength should be compensated by software method in the further. The system satisfies the demand of NIR micro-spectrometer with a single detector.

Bedside imaging of intracranial hemorrhage in the neonate using light: comparison with ultrasound, computed tomography, and magnetic resonance imaging.

PubMed

Hintz, S R; Cheong, W F; van Houten, J P; Stevenson, D K; Benaron, D A

1999-01-01

Medical optical imaging (MOI) uses light emitted into opaque tissues to determine the interior structure. Previous reports detailed a portable time-of-flight and absorbance system emitting pulses of near infrared light into tissues and measuring the emerging light. Using this system, optical images of phantoms, whole rats, and pathologic neonatal brain specimens have been tomographically reconstructed. We have now modified the existing instrumentation into a clinically relevant headband-based system to be used for optical imaging of structure in the neonatal brain at the bedside. Eight medical optical imaging studies in the neonatal intensive care unit were performed in a blinded clinical comparison of optical images with ultrasound, computed tomography, and magnetic resonance imaging. Optical images were interpreted as correct in six of eight cases, with one error attributed to the age of the clot, and one small clot not seen. In addition, one disagreement with ultrasound, not reported as an error, was found to be the result of a mislabeled ultrasound report rather than because of an inaccurate optical scan. Optical scan correlated well with computed tomography and magnetic resonance imaging findings in one patient. We conclude that light-based imaging using a portable time-of-flight system is feasible and represents an important new noninvasive diagnostic technique, with potential for continuous monitoring of critically ill neonates at risk for intraventricular hemorrhage or stroke. Further studies are now underway to further investigate the functional imaging capabilities of this new diagnostic tool.

Optical cryptography with biometrics for multi-depth objects.

PubMed

Yan, Aimin; Wei, Yang; Hu, Zhijuan; Zhang, Jingtao; Tsang, Peter Wai Ming; Poon, Ting-Chung

2017-10-11

We propose an optical cryptosystem for encrypting images of multi-depth objects based on the combination of optical heterodyne technique and fingerprint keys. Optical heterodyning requires two optical beams to be mixed. For encryption, each optical beam is modulated by an optical mask containing either the fingerprint of the person who is sending, or receiving the image. The pair of optical masks are taken as the encryption keys. Subsequently, the two beams are used to scan over a multi-depth 3-D object to obtain an encrypted hologram. During the decryption process, each sectional image of the 3-D object is recovered by convolving its encrypted hologram (through numerical computation) with the encrypted hologram of a pinhole image that is positioned at the same depth as the sectional image. Our proposed method has three major advantages. First, the lost-key situation can be avoided with the use of fingerprints as the encryption keys. Second, the method can be applied to encrypt 3-D images for subsequent decrypted sectional images. Third, since optical heterodyning scanning is employed to encrypt a 3-D object, the optical system is incoherent, resulting in negligible amount of speckle noise upon decryption. To the best of our knowledge, this is the first time optical cryptography of 3-D object images has been demonstrated in an incoherent optical system with biometric keys.

Two-photon laser scanning microscopy with electrowetting-based prism scanning

PubMed Central

Supekar, Omkar D.; Ozbay, Baris N.; Zohrabi, Mo; Nystrom, Philip D.; Futia, Gregory L.; Restrepo, Diego; Gibson, Emily A.; Gopinath, Juliet T.; Bright, Victor M.

2017-01-01

Laser scanners are an integral part of high resolution biomedical imaging systems such as confocal or 2-photon excitation (2PE) microscopes. In this work, we demonstrate the utility of electrowetting on dielectric (EWOD) prisms as a lateral laser-scanning element integrated in a conventional 2PE microscope. To the best of our knowledge, this is the first such demonstration for EWOD prisms. EWOD devices provide a transmissive, low power consuming, and compact alternative to conventional adaptive optics, and hence this technology has tremendous potential. We demonstrate 2PE microscope imaging of cultured mouse hippocampal neurons with a FOV of 130 × 130 μm2 using EWOD prism scanning. In addition, we show simulations of the optical system with the EWOD prism, to evaluate the effect of propagating a Gaussian beam through the EWOD prism on the imaging quality. Based on the simulation results a beam size of 0.91 mm full width half max was chosen to conduct the imaging experiments, resulting in a numerical aperture of 0.17 of the imaging system. PMID:29296477

Optical CT scanning of PRESAGETM polyurethane samples with a CCD-based readout system

NASA Astrophysics Data System (ADS)

Doran, S. J.; Krstajic, N.; Adamovics, J.; Jenneson, P. M.

2004-01-01

This article demonstrates the resolution capabilities of the CCD scanner under ideal circumstances and describes the first CCD-based optical CT experiments on a new class of dosimeter, known as PRESAGETM (Heuris Pharma, Skillman, NJ).

Correlative imaging of biological tissues with apertureless scanning near-field optical microscopy and confocal laser scanning microscopy

PubMed Central

Stanciu, Stefan G.; Tranca, Denis E.; Hristu, Radu; Stanciu, George A.

2017-01-01

Apertureless scanning near-field optical microscopy (ASNOM) has attracted considerable interest over the past years as a result of its valuable contrast mechanisms and capabilities for optical resolutions in the nanoscale range. However, at this moment the intersections between ASNOM and the realm of bioimaging are scarce, mainly due to data interpretation difficulties linked to the limited body of work performed so far in this field and hence the reduced volume of supporting information. We propose an imaging approach that holds significant potential for alleviating this issue, consisting of correlative imaging of biological specimens using a multimodal system that incorporates ASNOM and confocal laser scanning microscopy (CLSM), which allows placing near-field data into a well understood context of anatomical relevance. We demonstrate this approach on zebrafish retinal tissue. The proposed method holds important implications for the in-depth understanding of biological items through the prism of ASNOM and CLSM data complementarity. PMID:29296474

Spectral domain optical coherence tomography of multi-MHz A-scan rates at 1310 nm range and real-time 4D-display up to 41 volumes/second

PubMed Central

Choi, Dong-hak; Hiro-Oka, Hideaki; Shimizu, Kimiya; Ohbayashi, Kohji

2012-01-01

An ultrafast frequency domain optical coherence tomography system was developed at A-scan rates between 2.5 and 10 MHz, a B-scan rate of 4 or 8 kHz, and volume-rates between 12 and 41 volumes/second. In the case of the worst duty ratio of 10%, the averaged A-scan rate was 1 MHz. Two optical demultiplexers at a center wavelength of 1310 nm were used for linear-k spectral dispersion and simultaneous differential signal detection at 320 wavelengths. The depth-range, sensitivity, sensitivity roll-off by 6 dB, and axial resolution were 4 mm, 97 dB, 6 mm, and 23 μm, respectively. Using FPGAs for FFT and a GPU for volume rendering, a real-time 4D display was demonstrated at a rate up to 41 volumes/second for an image size of 256 (axial) × 128 × 128 (lateral) voxels. PMID:23243560

Portable Handheld Optical Window Inspection Device

NASA Technical Reports Server (NTRS)

Ihlefeld, Curtis; Dokos, Adam; Burns, Bradley

2010-01-01

The Portable Handheld Optical Window Inspection Device (PHOWID) is a measurement system for imaging small defects (scratches, pits, micrometeor impacts, and the like) in the field. Designed primarily for window inspection, PHOWID attaches to a smooth surface with suction cups, and raster scans a small area with an optical pen in order to provide a three-dimensional image of the defect. PHOWID consists of a graphical user interface, motor control subsystem, scanning head, and interface electronics, as well as an integrated camera and user display that allows a user to locate minute defects before scanning. Noise levels are on the order of 60 in. (1.5 m). PHOWID allows field measurement of defects that are usually done in the lab. It is small, light, and attaches directly to the test article in any orientation up to vertical. An operator can scan a defect and get useful engineering data in a matter of minutes. There is no need to make a mold impression for later lab analysis.

Augmenting the SCaN Link Budget Tool with Validated Atmospheric Propagation

NASA Technical Reports Server (NTRS)

Steinkerchner, Leo; Welch, Bryan

2017-01-01

In any Earth-Space or Space-Earth communications link, atmospheric effects cause significant signal attenuation. In order to develop a communications system that is cost effective while meeting appropriate performance requirements, it is important to accurately predict these effects for the given link parameters. This project aimed to develop a Matlab(TradeMark) (The MathWorks, Inc.) program that could augment the existing Space Communications and Navigation (SCaN) Link Budget Tool with accurate predictions of atmospheric attenuation of both optical and radio-frequency signals according to the SCaN Optical Link Assessment Model Version 5 and the International Telecommunications Union, Radiocommunications Sector (ITU-R) atmospheric propagation loss model, respectively. When compared to data collected from the Advance Communications Technology Satellite (ACTS), the radio-frequency model predicted attenuation to within 1.3 dB of loss for 95 of measurements. Ultimately, this tool will be integrated into the SCaN Center for Engineering, Networks, Integration, and Communications (SCENIC) user interface in order to support analysis of existing SCaN systems and planning capabilities for future NASA missions.

Silver nanoparticles as optical clearing agent enhancers to improve caries diagnostic by optical coherence tomography

NASA Astrophysics Data System (ADS)

Carneiro, Vanda S. M.; Mota, Cláudia C. B. O.; Souza, Alex F.; da Silva, Evair J.; da Silva, Andrea F.; Gerbi, Marleny E. M. M.; Gomes, Anderson S. L.

2018-02-01

The use of silver nanoparticles as optical clearing agent (OCA) enhancers to improve caries diagnostic by optical coherence tomography (OCT) is demonstrated here. Five molars with no evident cavitation were selected. The OCAs were based on aqueous solution of silver nanoparticles (AgNP, 1.18x 1014 particles/mL, ø ≈ 10nm) and its dilution at 10% in glycerol. Teeth were placed on a platform with a micrometric screw, and after applying the OCAs, they were scanned with a Callisto SD-OCT system operating ate 930nm central wavelength. The occlusal surfaces were scanned by OCT, capturing crosssectional images with 8 mm transversal scanning, generating numerical matrices (2000x512). The OCT images had their transverse dimension preserved. AgNP-OCAs promoted image stretching due to the modification in the light optical path caused by AgNP-OCAs refractive indices close to that of the enamel. AgNP-OCAs evidenced the enamel birefringence and highlighted initial demineralization areas, that presented defined margins with higher contrast between sound and demineralized regions, with higher OCT signal intensity in those areas.

Optical frequency comb Faraday rotation spectroscopy

NASA Astrophysics Data System (ADS)

Johansson, Alexandra C.; Westberg, Jonas; Wysocki, Gerard; Foltynowicz, Aleksandra

2018-05-01

We demonstrate optical frequency comb Faraday rotation spectroscopy (OFC-FRS) for broadband interference-free detection of paramagnetic species. The system is based on a femtosecond doubly resonant optical parametric oscillator and a fast-scanning Fourier transform spectrometer (FTS). The sample is placed in a DC magnetic field parallel to the light propagation. Efficient background suppression is implemented via switching the direction of the field on consecutive FTS scans and subtracting the consecutive spectra, which enables long-term averaging. In this first demonstration, we measure the entire Q- and R-branches of the fundamental band of nitric oxide in the 5.2-5.4 µm range and achieve good agreement with a theoretical model.

Ultraviolet absorption of common spacecraft contaminants. [to control effects of contaminants on optical systems

NASA Technical Reports Server (NTRS)

Colony, J. A.

1979-01-01

Organic contamination of ultraviolet optical systems is discussed. Degradation of signal by reflection, scattering, interference, and absorption is shown. The first three processes depend on the physical state of the contaminant while absorption depends on its chemical structure. The latter phenomenon is isolated from the others by dissolving contaminants in cyclohexane and determining absorption spectra from 2100A to 3600A. A variety of materials representing the types of contaminants responsible for most spaceflight hardware problems is scanned and the spectra is presented. The effect of thickness is demonstrated for the most common contaminant, di(2 ethyl hexyl)phthalate, by scanning successive dilutions.

Segmentation of 830- and 1310-nm LASIK corneal optical coherence tomography images

NASA Astrophysics Data System (ADS)

Li, Yan; Shekhar, Raj; Huang, David

2002-05-01

Optical coherence tomography (OCT) provides a non-contact and non-invasive means to visualize the corneal anatomy at micron scale resolution. We obtained corneal images from an arc-scanning (converging) OCT system operating at a wavelength of 830nm and a fan-shaped-scanning high-speed OCT system with an operating wavelength of 1310nm. Different scan protocols (arc/fan) and data acquisition rates, as well as wavelength dependent bio-tissue backscatter contrast and optical absorption, make the images acquired using the two systems different. We developed image-processing algorithms to automatically detect the air-tear interface, epithelium-Bowman's layer interface, laser in-situ keratomileusis (LASIK) flap interface, and the cornea-aqueous interface in both kinds of images. The overall segmentation scheme for 830nm and 1310nm OCT images was similar, although different strategies were adopted for specific processing approaches. Ultrasound pachymetry measurements of the corneal thickness and Placido-ring based corneal topography measurements of the corneal curvature were made on the same day as the OCT examination. Anterior/posterior corneal surface curvature measurement with OCT was also investigated. Results showed that automated segmentation of OCT images could evaluate anatomic outcome of LASIK surgery.

Comparison between Different Types of Sensors Used in the Real Operational Environment Based on Optical Scanning System.

PubMed

Flores-Fuentes, Wendy; Miranda-Vega, Jesús Elías; Rivas-López, Moisés; Sergiyenko, Oleg; Rodríguez-Quiñonez, Julio C; Lindner, Lars

2018-05-24

The present paper describes the experimentation in a controlled environment and a real environment using different photosensors, such as infrared light emitting diode (IRLED-as receiver), photodiode, light dependent resistor (LDR), and blue LED for the purpose of selecting those devices, which can be employed in adverse conditions, such as sunlight or artificial sources. The experiments that are described in this paper confirmed that the blue LED and phototransistor could be used as a photosensor of an Optical Scanning System (OSS), because they were less sensitive to sunlight radiation. Moreover, they are appropriate as reference sources that are selected for the experiment (blue LED flashlight and light bulb). The best experimental results that were obtained contained a digital filter that was applied to the output of the photosensor, which reduced the standard deviation for the best case for the phototransistor LED from 100.26 to 0.15. For the best case, using the blue LED, the standard deviation was reduced from 86.08 to 0.11. Using these types of devices the cost of the Optical Scanning System can be reduced and a considerable increase in resolution and accuracy.

Low Complexity Compression and Speed Enhancement for Optical Scanning Holography

PubMed Central

Tsang, P. W. M.; Poon, T.-C.; Liu, J.-P.; Kim, T.; Kim, Y. S.

2016-01-01

In this paper we report a low complexity compression method that is suitable for compact optical scanning holography (OSH) systems with different optical settings. Our proposed method can be divided into 2 major parts. First, an automatic decision maker is applied to select the rows of holographic pixels to be scanned. This process enhances the speed of acquiring a hologram, and also lowers the data rate. Second, each row of down-sampled pixels is converted into a one-bit representation with delta modulation (DM). Existing DM-based hologram compression techniques suffers from the disadvantage that a core parameter, commonly known as the step size, has to be determined in advance. However, the correct value of the step size for compressing each row of hologram is dependent on the dynamic range of the pixels, which could deviate significantly with the object scene, as well as OSH systems with different opical settings. We have overcome this problem by incorporating a dynamic step-size adjustment scheme. The proposed method is applied in the compression of holograms that are acquired with 2 different OSH systems, demonstrating a compression ratio of over two orders of magnitude, while preserving favorable fidelity on the reconstructed images. PMID:27708410

An improved three-dimensional non-scanning laser imaging system based on digital micromirror device

NASA Astrophysics Data System (ADS)

Xia, Wenze; Han, Shaokun; Lei, Jieyu; Zhai, Yu; Timofeev, Alexander N.

2018-01-01

Nowadays, there are two main methods to realize three-dimensional non-scanning laser imaging detection, which are detection method based on APD and detection method based on Streak Tube. However, the detection method based on APD possesses some disadvantages, such as small number of pixels, big pixel interval and complex supporting circuit. The detection method based on Streak Tube possesses some disadvantages, such as big volume, bad reliability and high cost. In order to resolve the above questions, this paper proposes an improved three-dimensional non-scanning laser imaging system based on Digital Micromirror Device. In this imaging system, accurate control of laser beams and compact design of imaging structure are realized by several quarter-wave plates and a polarizing beam splitter. The remapping fiber optics is used to sample the image plane of receiving optical lens, and transform the image into line light resource, which can realize the non-scanning imaging principle. The Digital Micromirror Device is used to convert laser pulses from temporal domain to spatial domain. The CCD with strong sensitivity is used to detect the final reflected laser pulses. In this paper, we also use an algorithm which is used to simulate this improved laser imaging system. In the last, the simulated imaging experiment demonstrates that this improved laser imaging system can realize three-dimensional non-scanning laser imaging detection.

A compact CCD-monitored atomic force microscope with optical vision and improved performances.

PubMed

Mingyue, Liu; Haijun, Zhang; Dongxian, Zhang

2013-09-01

A novel CCD-monitored atomic force microscope (AFM) with optical vision and improved performances has been developed. Compact optical paths are specifically devised for both tip-sample microscopic monitoring and cantilever's deflection detecting with minimized volume and optimal light-amplifying ratio. The ingeniously designed AFM probe with such optical paths enables quick and safe tip-sample approaching, convenient and effective tip-sample positioning, and high quality image scanning. An image stitching method is also developed to build a wider-range AFM image under monitoring. Experiments show that this AFM system can offer real-time optical vision for tip-sample monitoring with wide visual field and/or high lateral optical resolution by simply switching the objective; meanwhile, it has the elegant performances of nanometer resolution, high stability, and high scan speed. Furthermore, it is capable of conducting wider-range image measurement while keeping nanometer resolution. Copyright © 2013 Wiley Periodicals, Inc.

System and method for chromatography and electrophoresis using circular optical scanning

DOEpatents

Balch, Joseph W.; Brewer, Laurence R.; Davidson, James C.; Kimbrough, Joseph R.

2001-01-01

A system and method is disclosed for chromatography and electrophoresis using circular optical scanning. One or more rectangular microchannel plates or radial microchannel plates has a set of analysis channels for insertion of molecular samples. One or more scanning devices repeatedly pass over the analysis channels in one direction at a predetermined rotational velocity and with a predetermined rotational radius. The rotational radius may be dynamically varied so as to monitor the molecular sample at various positions along a analysis channel. Sample loading robots may also be used to input molecular samples into the analysis channels. Radial microchannel plates are built from a substrate whose analysis channels are disposed at a non-parallel angle with respect to each other. A first step in the method accesses either a rectangular or radial microchannel plate, having a set of analysis channels, and second step passes a scanning device repeatedly in one direction over the analysis channels. As a third step, the scanning device is passed over the analysis channels at dynamically varying distances from a centerpoint of the scanning device. As a fourth step, molecular samples are loaded into the analysis channels with a robot.

Design of a handheld optical coherence microscopy endoscope

NASA Astrophysics Data System (ADS)

Korde, Vrushali R.; Liebmann, Erica; Barton, Jennifer K.

2011-06-01

Optical coherence microscopy (OCM) combines coherence gating, high numerical aperture optics, and a fiber-core pinhole to provide high axial and lateral resolution with relatively large depth of imaging. We present a handheld rigid OCM endoscope designed for small animal surgical imaging, with a 6-mm diam tip, 1-mm scan width, and 1-mm imaging depth. X-Y scanning is performed distally with mirrors mounted to micro galvonometer scanners incorporated into the endoscope handle. The endoscope optical design consists of scanning doublets, an afocal Hopkins relay lens system, a 0.4 numerical aperture water immersion objective, and a cover glass. This endoscope can resolve laterally a 1.4-μm line pair feature and has an axial resolution (full width half maximum) of 5.4 μm. Images taken with this endoscope of fresh ex-vivo mouse ovaries show structural features, such as corpus luteum, primary follicles, growing follicles, and fallopian tubes. This rigid handheld OCM endoscope can be useful for a variety of minimally invasive and surgical imaging applications.

CONFERENCE NOTE: European Optical Society, Topical Meeting Optical Metrology and Nanotechnology, Engelberg, Switzerland, 27 30 March 1994

NASA Astrophysics Data System (ADS)

1993-01-01

This meeting, organized by the Paul Scherrer Institute's Department of Applied Solid State Physics, will be held from 27 30 March 1994 at the Hotel Regina-Titlis, Engelberg, Switzerland. The aim is to bring together scientists from two important fields of current research and increasing industrial relevance. Optical metrology is a traditional discipline of applied optics which reached the nanometre scale a long time ago. Nanotechnology is setting new limits and represents a major challenge to metrology, as well as offering new opportunities to optics. The meeting is intended to help define a common future for optical metrology and nanotechnology. Topics to be covered include: nanometre position control and measuring techniques ultrahigh precision interferometry scanning probe microscopy (AFM, SNOM, etc.) surface modification by scanning probe methods precision surface fabrication and characterization nanolithography micro-optics, diffractive optics components, including systems and applications subwavelength optical structures synthetic optical materials structures and technologies for X-ray optics. For further information please contact: Jens Gobrecht (Secretary), Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland.Tel. (41)56992529; Fax (41) 5698 2635.

Dental OCT

NASA Astrophysics Data System (ADS)

Colston, Bill W.; Sathyam, Ujwal S.; Dasilva, Luiz B.; Everett, Matthew J.; Stroeve, Pieter; Otis, L. L.

1998-09-01

We present here the first in vivo optical coherence tomography (OCT) images of human dental tissue. A novel dental optical coherence tomography system has been developed. This system incorporates the interferometer sample arm and transverse scanning optics into a handpiece that can be used intraorally to image human dental tissues. The average imaging depth of this system varied from 3 mm in hard tissues to 1.5 mm in soft tissues. We discuss the application of this imaging system for dentistry and illustrate the potential of our dental OCT system for diagnosis of periodontal disease, detection of caries, and evaluation of dental restorations.

Enhanced optical design by distortion control

NASA Astrophysics Data System (ADS)

Thibault, Simon; Gauvin, Jonny; Doucet, Michel; Wang, Min

2005-09-01

The control of optical distortion is useful for the design of a variety of optical system. The most popular is the F-theta lens used in laser scanning system to produce a constant scan velocity across the image plane. Many authors have designed during the last 20 years distortion control corrector. Today, many challenging digital imaging system can use distortion the enhanced their imaging capability. A well know example is a reversed telephoto type, if the barrel distortion is increased instead of being corrected; the result is a so-called Fish-eye lens. However, if we control the barrel distortion instead of only increasing it, the resulting system can have enhanced imaging capability. This paper will present some lens design and real system examples that clearly demonstrate how the distortion control can improve the system performances such as resolution. We present innovative optical system which increases the resolution in the field of view of interest to meet the needs of specific applications. One critical issue when we designed using distortion is the optimization management. Like most challenging lens design, the automatic optimization is less reliable. Proper management keeps the lens design within the correct range, which is critical for optimal performance (size, cost, manufacturability). Many lens design presented tailor a custom merit function and approach.

Theoretical modeling and evaluation of the axial resolution of the adaptive optics scanning laser ophthalmoscope.

PubMed

Venkateswaran, Krishnakumar; Roorda, Austin; Romero-Borja, Fernando

2004-01-01

We present axial resolution calculated using a mathematical model of the adaptive optics scanning laser ophthalmoscope (AOSLO). The peak intensity and the width of the axial intensity response are computed with the residual Zernike coefficients after the aberrations are corrected using adaptive optics for eight subjects and compared with the axial resolution of a diffraction-limited eye. The AOSLO currently uses a confocal pinhole that is 80 microm, or 3.48 times the width of the Airy disk radius of the collection optics, and projects to 7.41 microm on the retina. For this pinhole, the axial resolution of a diffraction-limited system is 114 microm and the computed axial resolution varies between 120 and 146 microm for the human subjects included in this study. The results of this analysis indicate that to improve axial resolution, it is best to reduce the pinhole size. The resulting reduction in detected light may demand, however, a more sophisticated adaptive optics system. The study also shows that imaging systems with large pinholes are relatively insensitive to misalignment in the lateral positioning of the confocal pinhole. However, when small pinholes are used to maximize resolution, alignment becomes critical. ( c) 2004 Society of Photo-Optical Instrumentation Engineers.

Elevation scanning laser/multi-sensor hazard detection system controller and mirror/mast speed control components. [roving vehicle electromechanical devices

NASA Technical Reports Server (NTRS)

Craig, J.; Yerazunis, S. W.

1978-01-01

The electro-mechanical and electronic systems involved with pointing a laser beam from a roving vehicle along a desired vector are described. A rotating 8 sided mirror, driven by a phase-locked dc motor servo system, and monitored by a precision optical shaft encoder is used. This upper assembly is then rotated about an orthogonal axis to allow scanning into all 360 deg around the vehicle. This axis is also driven by a phase locked dc motor servo-system, and monitored with an optical shaft encoder. The electronics are realized in standard TTL integrated circuits with UV-erasable proms used to store desired coordinates of laser fire. Related topics such as the interface to the existing test vehicle are discussed.

Advances in optical information processing IV; Proceedings of the Meeting, Orlando, FL, Apr. 18-20, 1990

NASA Astrophysics Data System (ADS)

Pape, Dennis R.

1990-09-01

The present conference discusses topics in optical image processing, optical signal processing, acoustooptic spectrum analyzer systems and components, and optical computing. Attention is given to tradeoffs in nonlinearly recorded matched filters, miniature spatial light modulators, detection and classification using higher-order statistics of optical matched filters, rapid traversal of an image data base using binary synthetic discriminant filters, wideband signal processing for emitter location, an acoustooptic processor for autonomous SAR guidance, and sampling of Fresnel transforms. Also discussed are an acoustooptic RF signal-acquisition system, scanning acoustooptic spectrum analyzers, the effects of aberrations on acoustooptic systems, fast optical digital arithmetic processors, information utilization in analog and digital processing, optical processors for smart structures, and a self-organizing neural network for unsupervised learning.

Miniaturized CARS microendoscope probe design for label-free intraoperative imaging

NASA Astrophysics Data System (ADS)

Chen, Xu; Wang, Xi; Xu, Xiaoyun; Cheng, Jie; Liu, Zhengfan; Weng, Sheng; Thrall, Michael J.; Goh, Alvin C.; McCormick, Daniel T.; Wong, Kelvin; Wong, Stephen T. C.

2014-03-01

A Coherent Anti-Stokes Raman Scattering (CARS) microendoscope probe for early stage label-free prostate cancer diagnosis at single cell resolution is presented. The handheld CARS microendoscope probe includes a customized micro-electromechanical systems (MEMS) scanning mirror as well as miniature optical and mechanical components. In our design, the excitation laser (pump and stokes beams) from the fiber is collimated, reflected by the reflecting mirror, and transmitted via a 2D MEMS scanning mirror and a micro-objective system onto the sample; emission in the epi-direction is returned through the micro-objective lens, MEMS and reflecting mirror, and collimation system, and finally the emission signal is collected by a photomultiplier tube (PMT). The exit pupil diameter of the collimator system is designed to match the diameter of the MEMS mirror and the entrance pupil diameter of the micro-objective system. The back aperture diameter of the micro-objective system is designed according to the largest MEMS scanning angle and the distance between the MEMS mirror and the back aperture. To increase the numerical aperture (NA) of the micro-objective system in order to enhance the signal collection efficiency, the back aperture diameter of the micro-objective system is enlarged with an upfront achromatic wide angle Keplerian telescope beam expander. The integration of a miniaturized micro-optics probe with optical fiber CARS microscopy opens up the possibility of in vivo molecular imaging for cancer diagnosis and surgical intervention.

Design and Construction of an Optical Computed Tomography Scanner for Polymer Gel Dosimetry Application

PubMed Central

Zakariaee, Seyed Salman; Mesbahi, Asghar; Keshtkar, Ahmad; Azimirad, Vahid

2014-01-01

Polymer gel dosimeter is the only accurate three dimensional (3D) dosimeter that can measure the absorbed dose distribution in a perfect 3D setting. Gel dosimetry by using optical computed tomography (OCT) has been promoted by several researches. In the current study, we designed and constructed a prototype OCT system for gel dosimetry. First, the electrical system for optical scanning of the gel container using a Helium-Neon laser and a photocell was designed and constructed. Then, the mechanical part for two rotational and translational motions was designed and step motors were assembled to it. The data coming from photocell was grabbed by the home-built interface and sent to a personal computer. Data processing was carried out using MATLAB software. To calibrate the system and tune up the functionality of it, different objects was designed and scanned. Furthermore, the spatial and contrast resolution of the system was determined. The system was able to scan the gel dosimeter container with a diameter up to 11 cm inside the water phantom. The standard deviation of the pixels within water flask image was considered as the criteria for image uniformity. The uniformity of the system was about ±0.05%. The spatial resolution of the system was approximately 1 mm and contrast resolution was about 0.2%. Our primary results showed that this system is able to obtain two-dimensional, cross-sectional images from polymer gel samples. PMID:24761377

In vivo integrated photoacoustic ophthalmoscopy, optical coherence tomography, and scanning laser ophthalmoscopy for retinal imaging

NASA Astrophysics Data System (ADS)

Song, Wei; Zhang, Rui; Zhang, Hao F.; Wei, Qing; Cao, Wenwu

2012-12-01

The physiological and pathological properties of retina are closely associated with various optical contrasts. Hence, integrating different ophthalmic imaging technologies is more beneficial in both fundamental investigation and clinical diagnosis of several blinding diseases. Recently, photoacoustic ophthalmoscopy (PAOM) was developed for in vivo retinal imaging in small animals, which demonstrated the capability of imaging retinal vascular networks and retinal pigment epithelium (RPE) at high sensitivity. We combined PAOM with traditional imaging modalities, such as fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), and auto-fluorescence scanning laser ophthalmoscopy (AF-SLO), for imaging rats and mice. The multimodal imaging system provided more comprehensive evaluation of the retina based on the complementary imaging contrast mechanisms. The high-quality retinal images show that the integrated ophthalmic imaging system has great potential in the investigation of blinding disorders.

Applying LED in full-field optical coherence tomography for gastrointestinal endoscopy

NASA Astrophysics Data System (ADS)

Yang, Bor-Wen; Wang, Yu-Yen; Juan, Yu-Shan; Hsu, Sheng-Jie

2015-08-01

Optical coherence tomography (OCT) has become an important medical imaging technology due to its non-invasiveness and high resolution. Full-field optical coherence tomography (FF-OCT) is a scanning scheme especially suitable for en face imaging as it employs a CMOS/CCD device for parallel pixels processing. FF-OCT can also be applied to high-speed endoscopic imaging. Applying cylindrical scanning and a right-angle prism, we successfully obtained a 360° tomography of the inner wall of an intestinal cavity through an FF-OCT system with an LED source. The 10-μm scale resolution enables the early detection of gastrointestinal lesions, which can increase detection rates for esophageal, stomach, or vaginal cancer. All devices used in this system can be integrated by MOEMS technology to contribute to the studies of gastrointestinal medicine and advanced endoscopy technology.

Fluorescence laminar optical tomography for brain imaging: system implementation and performance evaluation.

PubMed

Azimipour, Mehdi; Sheikhzadeh, Mahya; Baumgartner, Ryan; Cullen, Patrick K; Helmstetter, Fred J; Chang, Woo-Jin; Pashaie, Ramin

2017-01-01

We present our effort in implementing a fluorescence laminar optical tomography scanner which is specifically designed for noninvasive three-dimensional imaging of fluorescence proteins in the brains of small rodents. A laser beam, after passing through a cylindrical lens, scans the brain tissue from the surface while the emission signal is captured by the epi-fluorescence optics and is recorded using an electron multiplication CCD sensor. Image reconstruction algorithms are developed based on Monte Carlo simulation to model light–tissue interaction and generate the sensitivity matrices. To solve the inverse problem, we used the iterative simultaneous algebraic reconstruction technique. The performance of the developed system was evaluated by imaging microfabricated silicon microchannels embedded inside a substrate with optical properties close to the brain as a tissue phantom and ultimately by scanning brain tissue in vivo. Details of the hardware design and reconstruction algorithms are discussed and several experimental results are presented. The developed system can specifically facilitate neuroscience experiments where fluorescence imaging and molecular genetic methods are used to study the dynamics of the brain circuitries.

Evaluation of the smoothness and accuracy of scanning photorefractive keratectomy on PMMA by optical profilometry

NASA Astrophysics Data System (ADS)

Manns, Fabrice; Rol, Pascal O.; Parel, Jean-Marie A.; Schmid, Armin; Shen, Jin-Hui; Matsui, Takaaki; Soederberg, Per G.

1996-05-01

The smoothness and accuracy of PMMA ablations with a prototype scanning photorefractive keratectomy (SPRK) system were evaluated by optical profilometry. A prototype frequency- quintupled Nd:YAG laser (Laser Harmonic, LaserSight, Orlando, FL) was used (wavelength: 213 nm, pulse duration: 15 ns, repetition rate: 10 Hz). The laser energy was delivered through two computer-controlled galvanometer scanners that were controlled with our own hardware and software. The system was programmed to create on a block of PMMA the ablations corresponding to the correction of 6 diopters of myopia with 60%, 70%, and 80% spot overlap. The energy was 1.25 mJ. After ablation, the topography of the samples was measured with an optical profilometer (UBM Messtechnik, Ettlingen, Germany). The ablation depth was 10 to 15 micrometer larger than expected. The surfaces created with 50% to 70% overlap exhibited large saw-tooth like variations, with a maximum peak to peak variation of approximately 20 micrometer. With 80% overlap, the rms roughness was 1.3 micrometer and the central flattening was 7 diopters. This study shows that scanning PRK can produce smooth and accurate ablations.

Progress of Multi-Beam Long Trace-Profiler Development

NASA Technical Reports Server (NTRS)

Gubarev, Mikhail; Kilaru, Kiranmayee; Merthe, Daniel J.; Kester, Thomas; McKinney, Wayne R.; Takacs, Peter Z.; Yashchuk, Valeriy V.

2012-01-01

The multi-beam long trace profiler (LTP) under development at NASA s Marshall Space Flight Center[1] is designed to increase the efficiency of metrology of replicated X-ray optics. The traditional LTP operates on a single laser beam that scans along the test surface to detect the slope errors. While capable of exceptional surface slope accuracy, the LTP single beam scanning has slow measuring speed. As metrology constitutes a significant fraction of the time spent in optics production, an increase in the efficiency of metrology helps in decreasing the cost of fabrication of the x-ray optics and in improving their quality. Metrology efficiency can be increased by replacing the single laser beam with multiple beams that can scan a section of the test surface at a single instance. The increase in speed with such a system would be almost proportional to the number of laser beams. A collaborative feasibility study has been made and specifications were fixed for a multi-beam long trace profiler. The progress made in the development of this metrology system is presented.

Analysis of the dynamics and frequency spectrum synthesis of an optical-mechanical scanning device

NASA Technical Reports Server (NTRS)

Andryushkevichyus, A. I.; Kumpikas, A. L.; Kumpikas, K. L.

1973-01-01

A two-coordinate optical-mechanical scanning device (OMSD), the operating unit of which is a scanning disk, with directional and focusing optics and a board, on which the data carrier is placed, is examined. The disk and board are kinematically connected by a transmission mechanism, consisting of a worm and complex gear drive and a tightening screw-nut with correcting device, and it is run by a synchronous type motor. The dynamic errors in the system depend, first, on irregularities in rotation of the disk, fluctuations in its axis and vibrations of the table in the plane parallel to the plane of the disk. The basic sources of the fluctuations referred to above are residual disbalance of the rotor and other rotating masses, the periodic component of the driving torque of the synchronous motor, variability in the resistance, kinematic errors in the drive and other things. The fluctuations can be transmitted to the operating units through the kinematic link as a flexural-torsional system, as well as through vibrations of the housing of the device.

SU-F-T-235: Optical Scan Based Collision Avoidance Using Multiple Stereotactic Cameras During Simulation

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

Cardan, R; Popple, R; Dobelbower, M

Purpose: To demonstrate the ability to quickly generate an accurate collision avoidance map using multiple stereotactic cameras during simulation. Methods: Three Kinect stereotactic cameras were placed in the CT simulation room and optically calibrated to the DICOM isocenter. Immediately before scanning, the patient was optically imaged to generate a 3D polygon mesh, which was used to calculate the collision avoidance area using our previously developed framework. The mesh was visually compared to the CT scan body contour to ensure accurate coordinate alignment. To test the accuracy of the collision calculation, the patient and machine were physically maneuvered in the treatmentmore » room to calculated collision boundaries. Results: The optical scan and collision calculation took 38.0 seconds and 2.5 seconds to complete respectively. The collision prediction accuracy was determined using a receiver operating curve (ROC) analysis, where the true positive, true negative, false positive and false negative values were 837, 821, 43, and 79 points respectively. The ROC accuracy was 93.1% over the sampled collision space. Conclusion: We have demonstrated a framework which is fast and accurate for predicting collision avoidance for treatment which can be determined during the normal simulation process. Because of the speed, the system could be used to add a layer of safety with a negligible impact on the normal patient simulation experience. This information could be used during treatment planning to explore the feasible geometries when optimizing plans. Research supported by Varian Medical Systems.« less

Commissioning of an integrated platform for time-resolved treatment delivery in scanned ion beam therapy by means of optical motion monitoring.

PubMed

Fattori, G; Saito, N; Seregni, M; Kaderka, R; Pella, A; Constantinescu, A; Riboldi, M; Steidl, P; Cerveri, P; Bert, C; Durante, M; Baroni, G

2014-12-01

The integrated use of optical technologies for patient monitoring is addressed in the framework of time-resolved treatment delivery for scanned ion beam therapy. A software application has been designed to provide the therapy control system (TCS) with a continuous geometrical feedback by processing the external surrogates tridimensional data, detected in real-time via optical tracking. Conventional procedures for phase-based respiratory phase detection were implemented, as well as the interface to patient specific correlation models, in order to estimate internal tumor motion from surface markers. In this paper, particular attention is dedicated to the quantification of time delays resulting from system integration and its compensation by means of polynomial interpolation in the time domain. Dedicated tests to assess the separate delay contributions due to optical signal processing, digital data transfer to the TCS and passive beam energy modulation actuation have been performed. We report the system technological commissioning activities reporting dose distribution errors in a phantom study, where the treatment of a lung lesion was simulated, with both lateral and range beam position compensation. The zero-delay systems integration with a specific active scanning delivery machine was achieved by tuning the amount of time prediction applied to lateral (14.61 ± 0.98 ms) and depth (34.1 ± 6.29 ms) beam position correction signals, featuring sub-millimeter accuracy in forward estimation. Direct optical target observation and motion phase (MPh) based tumor motion discretization strategies were tested, resulting in 20.3(2.3)% and 21.2(9.3)% median (IQR) percentual relative dose difference with respect to static irradiation, respectively. Results confirm the technical feasibility of the implemented strategy towards 4D treatment delivery, with negligible percentual dose deviations with respect to static irradiation.

PC-Based systems for experiments in optical characterization of materials

NASA Astrophysics Data System (ADS)

López-Mora, C. C.; Trejo-Duran, M.; Alvarado-Méndez, E.; Rojas-Laguna, R.; Vargas-Rodríguez, E.; Estudillo-Ayala, J. M.; Mata-Chavez, R.; Sukhoivanov, I.; García-Pérez, A.; Ibarra-Manzano, O. G.; Andrade-Lucio, J. A.

2011-01-01

An automatic control for applications of optical characterization of materials using the optical Z-Scan technique is presented in this work. The emphasis is placed in the design of the graphical user interface (GUI) and the automation process. For this purpose, we use a USB data acquisition module with programmable I/O ports for control and signals acquisition for the complete system. The control software was developed using the graphical programming language LabVIEW® and compiled in order to obtain a portable system with the hardware used in this work.

Evaluation of the clinical efficacy of the PeTrack motion tracking system for respiratory gating in cardiac PET imaging

NASA Astrophysics Data System (ADS)

Manwell, Spencer; Chamberland, Marc J. P.; Klein, Ran; Xu, Tong; deKemp, Robert

2017-03-01

Respiratory gating is a common technique used to compensate for patient breathing motion and decrease the prevalence of image artifacts that can impact diagnoses. In this study a new data-driven respiratory gating method (PeTrack) was compared with a conventional optical tracking system. The performance of respiratory gating of the two systems was evaluated by comparing the number of respiratory triggers, patient breathing intervals and gross heart motion as measured in the respiratory-gated image reconstructions of rubidium-82 cardiac PET scans in test and control groups consisting of 15 and 8 scans, respectively. We found evidence suggesting that PeTrack is a robust patient motion tracking system that can be used to retrospectively assess patient motion in the event of failure of the conventional optical tracking system.

Goddard Conference on Mass Storage Systems and Technologies, Volume 1

NASA Technical Reports Server (NTRS)

Kobler, Ben (Editor); Hariharan, P. C. (Editor)

1993-01-01

Copies of nearly all of the technical papers and viewgraphs presented at the Goddard Conference on Mass Storage Systems and Technologies held in Sep. 1992 are included. The conference served as an informational exchange forum for topics primarily relating to the ingestion and management of massive amounts of data and the attendant problems (data ingestion rates now approach the order of terabytes per day). Discussion topics include the IEEE Mass Storage System Reference Model, data archiving standards, high-performance storage devices, magnetic and magneto-optic storage systems, magnetic and optical recording technologies, high-performance helical scan recording systems, and low end helical scan tape drives. Additional topics addressed the evolution of the identifiable unit for processing purposes as data ingestion rates increase dramatically, and the present state of the art in mass storage technology.

High-Speed Terahertz Waveform Measurement for Intense Terahertz Light Using 100-kHz Yb-Doped Fiber Laser.

PubMed

Tsubouchi, Masaaki; Nagashima, Keisuke

2018-06-14

We demonstrate a high-speed terahertz (THz) waveform measurement system for intense THz light with a scan rate of 100 Hz. To realize the high scan rate, a loudspeaker vibrating at 50 Hz is employed to scan the delay time between THz light and electro-optic sampling light. Because the fast scan system requires a high data sampling rate, we develop an Yb-doped fiber laser with a repetition rate of 100 kHz optimized for effective THz light generation with the output electric field of 1 kV/cm. The present system drastically reduces the measurement time of the THz waveform from several minutes to 10 ms.

Silicon technology-based micro-systems for atomic force microscopy/photon scanning tunnelling microscopy.

PubMed

Gall-Borrut, P; Belier, B; Falgayrettes, P; Castagne, M; Bergaud, C; Temple-Boyer, P

2001-04-01

We developed silicon nitride cantilevers integrating a probe tip and a wave guide that is prolonged on the silicon holder with one or two guides. A micro-system is bonded to a photodetector. The resulting hybrid system enables us to obtain simultaneously topographic and optical near-field images. Examples of images obtained on a longitudinal cross-section of an optical fibre are shown.

Optical Interferometric Micrometrology

NASA Technical Reports Server (NTRS)

Abel, Phillip B.; Lauer, James R.

1989-01-01

Resolutions in angstrom and subangstrom range sought for atomic-scale surface probes. Experimental optical micrometrological system built to demonstrate calibration of piezoelectric transducer to displacement sensitivity of few angstroms. Objective to develop relatively simple system producing and measuring translation, across surface of specimen, of stylus in atomic-force or scanning tunneling microscope. Laser interferometer used to calibrate piezoelectric transducer used in atomic-force microscope. Electronic portion of calibration system made of commercially available components.

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.

Optical Testing Using Portable Laser Coordinate Measuring Instruments

NASA Technical Reports Server (NTRS)

Khreishi, Manal; Ohl, Raymond G.; Mclean, Kyle F.; Hadjimichael, Theodore J.; Hayden, Joseph E.

2017-01-01

High precision, portable coordinate measuring instruments (CMI) such as laser radars (LR) and laser trackers (LT) have been used for optical system alignment and integration. The LR's ability to perform a non-contact scan of surfaces was previously utilized to characterize large spherical and aspheric mirrors. In this paper, we explore the use of a CMI as an accurate, fast, robust, and non-contact tool for prescription characterization of powered optical surfaces. Using Nikon's MV-224/350 LR and Leica's Absolute Tracker AT401/402 instruments, proof of concept measurements were performed to characterize a variety of optical components by measuring the actual and apparent, or equivalently the "direct and through" (D&T), coordinates of calibrated metrology targets. Custom macros in metrology software and other data reduction code were developed to compute surface-ray intercepts and surface slopes from the D&T shots. The calculated data is fit to an aspheric surface formula to obtain the optimum prescription. The results were compared to the nominal parameters and were crosschecked using LR scans or other approaches. We discuss potential applications across the fields of optical component fabrication and system alignment and testing.

Optical Testing Using Portable Laser Coordinate Measuring Instruments

NASA Technical Reports Server (NTRS)

Khreishi, M.; Ohl, R.; Mclean, K.; Hadjimichael, T.; Hayden, J.

2017-01-01

High precision, portable coordinate measuring instruments (CMI) such as laser radars (LR) and laser trackers (LT) have been used for optical system alignment and integration. The LRs ability to perform a non-contact scan of surfaces was previously utilized to characterize large spherical and aspheric mirrors. In this paper, we explore the use of a CMI as an accurate, fast, robust, and non-contact tool for prescription characterization of powered optical surfaces. Using Nikons MV-224350 LR and Leicas Absolute Tracker AT401402 instruments, proof of concept measurements were performed to characterize a variety of optical components by measuring the actual and apparent, or equivalently the direct and through (DT), coordinates of calibrated metrology targets. Custom macros in metrology software and other data reduction code were developed to compute surface-ray intercepts and surface slopes from the DT shots. The calculated data is fit to an aspheric surface formula to obtain the optimum prescription. The results were compared to the nominal parameters and were crosschecked using LR scans or other approaches. We discuss potential applications across the fields of optical component fabrication and system alignment and testing.

Optical signal processing

NASA Astrophysics Data System (ADS)

Vanderlugt, A.

1993-07-01

A quasi-realtime adaptive processing system was used to correct the multipath distortion found in wideband digital radios. The measured power spectral density of the input signal was used to adaptively select one of eight equalization filters which reduce the residual distortion to less than 3.6 dB even for the most severe channel distortion. A related adaptive system was used for signal excision in which we removed narrowband interference from wideband signals with minimum signal distortion. An 8x8 acousto-optic switch in a multimode fiber-optic system was built. Insertion loss is approximately 2-4 dB, signal-to-crosstalk ratio is better than 25 dB, and the reconfiguration time is 880 nsec. Short pulses were detected by using the Fresnel transform. Pulses as short as the theoretical limit of 20 nanoseconds were detected for this system, and separated by as little as 60 nanoseconds or by as much as 17 nanoseconds. All possible acousto-optic scanning configurations were considered and classified into four basic types. A consistent set of design relationships for each of the scanning configurations was developed and presented in both tabular and graphic forms from which a preliminary design is obtained.

Scanning micro-resonator direct-comb absolute spectroscopy

PubMed Central

Gambetta, Alessio; Cassinerio, Marco; Gatti, Davide; Laporta, Paolo; Galzerano, Gianluca

2016-01-01

Direct optical Frequency Comb Spectroscopy (DFCS) is proving to be a fundamental tool in many areas of science and technology thanks to its unique performance in terms of ultra-broadband, high-speed detection and frequency accuracy, allowing for high-fidelity mapping of atomic and molecular energy structure. Here we present a novel DFCS approach based on a scanning Fabry-Pérot micro-cavity resonator (SMART) providing a simple, compact and accurate method to resolve the mode structure of an optical frequency comb. The SMART approach, while drastically reducing system complexity, allows for a straightforward absolute calibration of the optical-frequency axis with an ultimate resolution limited by the micro-resonator resonance linewidth and can be used in any spectral region from UV to THz. We present an application to high-precision spectroscopy of acetylene at 1.54 μm, demonstrating performances comparable or even better than current state-of-the-art DFCS systems in terms of sensitivity, optical bandwidth and frequency-resolution. PMID:27752132

Optical textile tests MRI patients from afar

NASA Astrophysics Data System (ADS)

Gould, Paula

2008-11-01

Researchers in Europe have developed a wearable textile fitted with optical sensors that could be used to remotely monitor a patient's breathing patterns while they undergo magnetic resonance imaging (MRI) scans. The new textile will allow medical staff to keep an eye on children and other vulnerable patients who often have to be calmed with sedatives or anaesthetic drugs to keep them still during a scan. The technique will be particularly useful if proposed European Union (EU) legislation that is designed to protect medical staff from being exposed to the high magnetic fields of MRI systems comes into force in 2012. The new rules would prevent nurses from being in the room where the scan is taking place.

High numerical aperture projection system for extreme ultraviolet projection lithography

DOEpatents

Hudyma, Russell M.

2000-01-01

An optical system is described that is compatible with extreme ultraviolet radiation and comprises five reflective elements for projecting a mask image onto a substrate. The five optical elements are characterized in order from object to image as concave, convex, concave, convex, and concave mirrors. The optical system is particularly suited for ring field, step and scan lithography methods. The invention uses aspheric mirrors to minimize static distortion and balance the static distortion across the ring field width which effectively minimizes dynamic distortion. The present invention allows for higher device density because the optical system has improved resolution that results from the high numerical aperture, which is at least 0.14.

Increased illumination uniformity and reduced photodamage offered by the Lissajous scanning in fiber-optic two-photon endomicroscopy

NASA Astrophysics Data System (ADS)

Liang, Wenxuan; Murari, Kartikeya; Zhang, Yuying; Chen, Yongping; Li, Ming-Jun; Li, Xingde

2012-02-01

We compare the illumination uniformity and the associated effects of the spiral and Lissajous scanning patterns that are commonly used in an endomicroscope. Theoretical analyses and numerical simulations were first performed to quantitatively investigate the area illumination density in the spiral scanning pattern. The results revealed the potential problem of manifest photodamage due to the very high illumination density in the center of the spiral scan. Similar analyses of the Lissajous scanning pattern, which can be conveniently implemented on the same endomicroscope with no hardware modifications, showed a more uniform illumination density with about an 80-fold reduction in the peak illumination density. To underscore the benefit offered by the improved illumination uniformity, we conducted in vitro two-photon fluorescence imaging of cultured cells stained with a LIVE/DEAD viability assay using our home-built, fiber-optic, two-channel endomicroscopy system. Both the spiral and the Lissajous scans were implemented. Our experimental results showed that cells near the spiral scan center experienced obvious photodamage, whereas cells remained alive over the entire region under the Lissajous beam scanning, confirming the predicted advantage offered by the Lissajous scan over this spiral scan in an endomicroscopy setting.

The remote measurement of tornado-like flows employing a scanning laser Doppler system

NASA Technical Reports Server (NTRS)

Jeffreys, H. B.; Bilbro, J. W.; Dimarzio, C.; Sonnenschein, C.; Toomey, D.

1977-01-01

The paper deals with a scanning laser Doppler velocimeter system employed in a test program for measuring naturally occurring tornado-like phenomena, known as dust devils. A description of the system and the test program is followed by a discussion of the data processing techniques and data analysis. The system uses a stable 15-W CO2 laser with the beam expanded and focused by a 12-inch telescope. Range resolution is obtained by focusing the optical system. The velocity of each volume of air (scanned in a horizontal plane) is determined from spectral analysis of the heterodyne signal. Results derived from the measurement program and data/system analyses are examined.

Broad band nonlinear optical absorption measurements of the laser dye IR26 using white light continuum Z-scan

NASA Astrophysics Data System (ADS)

Dey, Soumyodeep; Bongu, Sudhakara Reddy; Bisht, Prem Ballabh

2017-03-01

We study the nonlinear optical response of a standard dye IR26 using the Z-scan technique, but with the white light continuum. The continuum source of wavelength from 450 nm to 1650 nm has been generated from the photonic crystal fiber on pumping with 772 nm of Ti:Sapphire oscillator. The use of broadband incident pulse enables us to probe saturable absorption (SA) and reverse saturable absorption (RSA) over the large spectral range with a single Z-scan measurement. The system shows SA in the resonant region while it turns to RSA in the non-resonant regions. The low saturation intensity of the dye can be explained based on the simultaneous excitation from ground states to various higher energy levels with the help of composite energy level diagram. The cumulative effects of excited state absorption and thermal induced nonlinear optical effects are responsible for the observed RSA.

Input signal shaping based on harmonic frequency response function for suppressing nonlinear optical frequency in frequency-scanning interferometry

NASA Astrophysics Data System (ADS)

Zhu, Yu; Liu, Zhigang; Deng, Wen; Deng, Zhongwen

2018-05-01

Frequency-scanning interferometry (FSI) using an external cavity diode laser (ECDL) is essential for many applications of the absolute distance measurement. However, owing to the hysteresis and creep of the piezoelectric actuator inherent in the ECDL, the optical frequency scanning exhibits a nonlinearity that seriously affects the phase extraction accuracy of the interference signal and results in the reduction of the measurement accuracy. To suppress the optical frequency nonlinearity, a harmonic frequency synthesis method for shaping the desired input signal instead of the original triangular wave is presented. The effectiveness of the presented shaping method is demonstrated through the comparison of the experimental results. Compared with an incremental Renishaw interferometer, the standard deviation of the displacement measurement of the FSI system is less than 2.4 μm when driven by the shaped signal.

Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing (PHASERS)

NASA Technical Reports Server (NTRS)

Guerra, David V.; Schwemmer, Geary K.; Wooten, Albert D., Jr.; Chaudhuri, Sandipan S.; Wilkerson, Thomas D.

1995-01-01

A ground-based atmospheric lidar system that utilizes a Holographic Optical Telescope and Scanner has been developed and successfully operated to obtain atmospheric backscatter profiles. The Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing is built around a volume phase reflection Holographic Optical Element. This single optical element both directs and collimates the outgoing laser beam as well as collects, focuses, and filters the atmospheric laser backscatter, while offering significant weight savings over existing telescope mirror technology. Conical scanning is accomplished as the HOE rotates on a turntable sweeping the 1.2 mrad field of view around a 42deg cone. During this technology demonstration, atmospheric aerosol and cloud return signals have been received in both stationary and scanning modes. The success of this program has led to the further development of this technology for integration into airborne and eventually satellite earth observing scanning lidar telescopes.

Full color laser projection display using Kr-Ar laser (white laser) beam-scanning technology

NASA Astrophysics Data System (ADS)

Kim, Yonghoon; Lee, Hang W.; Cha, Seungnam; Lee, Jin-Ho; Park, Youngjun; Park, Jungho; Hong, Sung S.; Hwang, Young M.

1997-07-01

Full color laser projection display is realized on the large screen using a krypton-argon laser (white laser) as a light source, and acousto-optic devices as light modulators. The main wavelengths of red, green and blue color are 647, 515, and 488 nm separated by dichroic mirrors which are designed to obtain the best performance for the s-polarized beam with the 45 degree incident angle. The separated beams are modulated by three acousto-optic modulators driven by rf drivers which has energy level of 1 watt at 144 MHz and recombined by dichroic mirrors again. Acousto-optic modulators (AOM) are fabricated to satisfy high diffraction efficiency over 80% and fast rising time less than 50 ns at the video bandwidth of 5 MHz. The recombined three beams (RGB) are scanned by polygonal mirrors for horizontal lines and a galvanometer for vertical lines. The photodiode detection for monitoring of rotary polygonal mirrors is adopted in this system for the compensation of the tolerance in the mechanical scanning to prevent the image joggling in the horizontal direction. The laser projection display system described in this paper is expected to apply HDTV from the exploitation of the acousto- optic modulator with the video bandwidth of 30 MHz.

Experimental demonstration of conformal phased array antenna via transformation optics.

PubMed

Lei, Juan; Yang, Juxing; Chen, Xi; Zhang, Zhiya; Fu, Guang; Hao, Yang

2018-02-28

Transformation Optics has been proven a versatile technique for designing novel electromagnetic devices and it has much wider applicability in many subject areas related to general wave equations. Among them, quasi-conformal transformation optics (QCTO) can be applied to minimize anisotropy of transformed media and has opened up the possibility to the design of broadband antennas with arbitrary geometries. In this work, a wide-angle scanning conformal phased array based on all-dielectric QCTO lens is designed and experimentally demonstrated. Excited by the same current distribution as such in a conventional planar array, the conformal system in presence of QCTO lens can preserve the same radiation characteristics of a planar array with wide-angle beam-scanning and low side lobe level (SLL). Laplace's equation subject to Dirichlet-Neumann boundary conditions is adopted to construct the mapping between the virtual and physical spaces. The isotropic lens with graded refractive index is realized by all-dielectric holey structure after an effective parameter approximation. The measurements of the fabricated system agree well with the simulated results, which demonstrate its excellent wide-angle beam scanning performance. Such demonstration paves the way to a robust but efficient array synthesis, as well as multi-beam and beam forming realization of conformal arrays via transformation optics.

Time-domain optical mammography Softscan: initial results on detection and characterization of breast tumors

NASA Astrophysics Data System (ADS)

Intes, Xavier; Djeziri, Salim; Ichalalene, Zahia; Mincu, Niculae; Wang, Yong; St.-Jean, Philippe; Lesage, Frédéric; Hall, David; Boas, David A.; Polyzos, Margaret

2004-10-01

Near-infrared (NIR) technology appears promising as a non-invasive clinical technique for breast cancer screening and diagnosis. The technology capitalizes on the relative transparency of human tissue in this spectral range and its sensitivity to the main components of the breast:; water, lipid and hemoglobin. In this work we present initial results obtained using the SoftScan® breast-imaging system developed by ART, Advanced Research Technologies inc., Montreal. This platform consists of a 4-wavelength time-resolved scanning system used to quantify non-invasively the local functional state of breast tissue. The different aspects of the system used to retrieve 3D optical contrast will be presented. Furthermore, preliminary data obtained from a prospective study conducted at The Royal Victoria Hospital of the McGill University Health Center in Montreal will be discussed. Analysis of the data gathered by SoftScan® demonstrated the potential of the technology in discriminating between healthy and diseased tissue.

Anterior Eye Imaging with Optical Coherence Tomography

NASA Astrophysics Data System (ADS)

Huang, David; Li, Yan; Tang, Maolong

The development of corneal and anterior segment optical coherence tomography (OCT) technology has advanced rapidly in recently years. The scan geometry and imaging wavelength are both important choices to make in designing anterior segment OCT systems. Rectangular scan geometry offers the least image distortion and is now used in most anterior OCT systems. The wavelength of OCT light source affects resolution and penetration. An optimal choice of the OCT imaging wavelength (840, 1,050, or 1,310 nm) depends on the application of interest. Newer generation Fourier-domain OCT technology can provide scan speed 100-1000 times faster than the time-domain technology. Various commercial anterior OCT systems are available on the market. A wide spectrum of diagnostic and surgical applications using anterior segment OCT had been investigated, including mapping of corneal and epithelial thicknesses, keratoconus screening, measuring corneal refractive power, corneal surgery planning and evaluation in LASIK, intracorneal ring implantation, assessment of angle closure glaucoma, anterior chamber biometry and intraocular lens implants, intraocular lens power calculation, and eye bank donor cornea screening.

Design of a Compact, Bimorph Deformable Mirror-Based Adaptive Optics Scanning Laser Ophthalmoscope.

PubMed

He, Yi; Deng, Guohua; Wei, Ling; Li, Xiqi; Yang, Jinsheng; Shi, Guohua; Zhang, Yudong

2016-01-01

We have designed, constructed and tested an adaptive optics scanning laser ophthalmoscope (AOSLO) using a bimorph mirror. The simulated AOSLO system achieves diffraction-limited criterion through all the raster scanning fields (6.4 mm pupil, 3° × 3° on pupil). The bimorph mirror-based AOSLO corrected ocular aberrations in model eyes to less than 0.1 μm RMS wavefront error with a closed-loop bandwidth of a few Hz. Facilitated with a bimorph mirror at a stroke of ±15 μm with 35 elements and an aperture of 20 mm, the new AOSLO system has a size only half that of the first-generation AOSLO system. The significant increase in stroke allows for large ocular aberrations such as defocus in the range of ±600° and astigmatism in the range of ±200°, thereby fully exploiting the AO correcting capabilities for diseased human eyes in the future.

Accuracy of i-Scan for Optical Diagnosis of Colonic Polyps: A Meta-Analysis

PubMed Central

Guo, Chuan-Guo; Ji, Rui; Li, Yan-Qing

2015-01-01

Background i-Scan is a novel virtual chromoendoscopy system designed to enhance surface and vascular patterns to improve optical diagnostic performance. Numerous prospective studies have been done to evaluate the accuracy of i-Scan in differentiating colonic neoplasms from non-neoplasms. i-Scan could be an effective endoscopic technique for optical diagnosis of colonic polyps. Objective Our aim of this study was to perform a meta-analysis of published data to establish the diagnostic accuracy of i-Scan for optical diagnosis of colonic polyps. Methods We searched PubMed, Medline, Elsevier ScienceDirect and Cochrane Library databases. We used a bivariate meta-analysis following a random effects model to summarize the data and plotted hierarchical summary receiver-operating characteristic (HSROC) curves. The area under the HSROC curve (AUC) serves as an indicator of the diagnostic accuracy. Results The meta-analysis included a total of 925 patients and 2312 polyps. For the overall studies, the area under the HSROC curve was 0.96. The summary sensitivity was 90.4% (95%CI 85%-94.1%) and specificity was 90.9% (95%CI 84.3%-94.9%). In 11 studies predicting polyps histology in real-time, the summary sensitivity and specificity was 91.5% (95%CI 85.7%-95.1%) and 92.1% (95%CI 84.5%-96.1%), respectively, with the AUC of 0.97. For three different diagnostic criteria (Kudo, NICE, others), the sensitivity was 86.3%, 93.0%, 85.0%, respectively and specificity was 84.8%, 94.4%, 91.8%, respectively. Conclusions Endoscopic diagnosis with i-Scan has accurate optical diagnostic performance to differentiate neoplastic from non-neoplastic polyps with an area under the HSROC curve exceeding 0.90. Both the sensitivity and specificity for diagnosing colonic polyps are over 90%. PMID:25978459

On-Board Imaging Validation of Optically Guided Stereotactic Radiosurgery Positioning System for Conventionally Fractionated Radiotherapy for Paranasal Sinus and Skull Base Cancer

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

Maxim, Peter G.; Loo, Billy W.; Murphy, James D.

2011-11-15

Purpose: To evaluate the positioning accuracy of an optical positioning system for stereotactic radiosurgery in a pilot experience of optically guided, conventionally fractionated, radiotherapy for paranasal sinus and skull base tumors. Methods and Materials: Before each daily radiotherapy session, the positioning of 28 patients was set up using an optical positioning system. After this initial setup, the patients underwent standard on-board imaging that included daily orthogonal kilovoltage images and weekly cone beam computed tomography scans. Daily translational shifts were made after comparing the on-board images with the treatment planning computed tomography scans. These daily translational shifts represented the daily positionalmore » error in the optical tracking system and were recorded during the treatment course. For 13 patients treated with smaller fields, a three-degree of freedom (3DOF) head positioner was used for more accurate setup. Results: The mean positional error for the optically guided system in patients with and without the 3DOF head positioner was 1.4 {+-} 1.1 mm and 3.9 {+-} 1.6 mm, respectively (p <.0001). The mean positional error drifted 0.11 mm/wk upward during the treatment course for patients using the 3DOF head positioner (p = .057). No positional drift was observed in the patients without the 3DOF head positioner. Conclusion: Our initial clinical experience with optically guided head-and-neck fractionated radiotherapy was promising and demonstrated clinical feasibility. The optically guided setup was especially useful when used in conjunction with the 3DOF head positioner and when it was recalibrated to the shifts using the weekly portal images.« less

Wide-field high-performance geosynchronous imaging

NASA Astrophysics Data System (ADS)

Wood, H. John; Jenstrom, Del; Wilson, Mark; Hinkal, Sanford; Kirchman, Frank

1998-01-01

The NASA Mission to Planet Earth (MTPE) Program and the National Oceanographic and Atmospheric Administration (NOAA) are sponsoring the Advanced Geosynchronous Studies (AGS) to develop technologies and system concepts for Earth observation from geosynchronous orbit. This series of studies is intended to benefit both MTPE science and the NOAA GOES Program. Within the AGS program, advanced imager trade studies have investigated two candidate concepts for near-term advanced geosynchronous imagers. One concept uses a scan mirror to direct the line of sight from a 3-axis stabilized platform. Another eliminates the need for a scan mirror by using an agile spacecraft bus to scan the entire instrument. The purpose of this paper is to discuss the optical design trades and system issues encountered in evaluating the two scanning approaches. The imager design started with a look at first principles: what is the most efficient way to image the Earth in those numerous spectral bands of interest to MTPE scientists and NOAA weather forecasters. Optical design trades included rotating filter wheels and dispersive grating instruments. The design converged on a bandpass filter instrument using four focal planes to cover the spectral range 0.45 to 13.0 micrometers. The first imager design uses a small agile spacecraft supporting an afocal optical telescope. Dichroic beamsplitters feed refractive objectives to four focal planes. The detectors are a series of long linear and rectangular arrays which are scanned in a raster fashion over the 17 degree Earth image. The use of the spacecraft attitude control system to raster the imager field-of-view (FOV) back and forth over the Earth eliminates the need for a scan mirror. However, the price paid is significant energy and time required to reverse the spacecraft slew motions at the end of each scan line. Hence, it is desired to minimize the number of scan lines needed to cover the full Earth disk. This desire, coupled with the ground coverage requirements, drives the telescope design to a 1.6 degree square FOV to provide full Earth disk coverage in less than 12 swaths. The telescope design to accommodate the FOV and image quality requirements is a 30 cm aperture three-element off-axis anastigmat. The size and mass of the imager instrument that result from this optical configuration are larger than desired. But spacecraft reaction wheel torque and power requirements to raster the imager FOV are achievable using existing spacecraft technology. However, launch mass and cost are higher than desired. In the second high-level trade study, the AGS imager team is looking at incorporating a scan mirror and having the satellite three-axis stabilized. The use of the scan mirror eliminates the long turn-around times of the spacecraft scanning approach, allowing for faster Earth coverage. Thus the field of view of the afocal telescope can be reduced by half while still satisfying ground coverage requirements. The optical design of the reduced field afocal telescope is being studied to shrink its size and improve its performance. Both a three-mirror Cassegrain afocal and a two-mirror pair of confocal paraboloids are being considered. With either telescope, the size, mass, and power requirements of this imager are significantly less than those of the first imager design. Both imager designs appear to be feasible and both meet envisioned MTPE and NOAA geosynchronous imaging needs. The AGS imager team is continuing to explore the optical trade space to further optimize imager designs.

High-resolution adaptive optics scanning laser ophthalmoscope with multiple deformable mirrors

DOEpatents

Chen, Diana C.; Olivier, Scot S.; Jones; Steven M.

2010-02-23

An adaptive optics scanning laser ophthalmoscopes is introduced to produce non-invasive views of the human retina. The use of dual deformable mirrors improved the dynamic range for correction of the wavefront aberrations compared with the use of the MEMS mirror alone, and improved the quality of the wavefront correction compared with the use of the bimorph mirror alone. The large-stroke bimorph deformable mirror improved the capability for axial sectioning with the confocal imaging system by providing an easier way to move the focus axially through different layers of the retina.

Phenomenal enhancement of optical nonlinearity in PTZ-I based ZnS/ZnSe nanocomposites

NASA Astrophysics Data System (ADS)

Divyasree, M. C.; Shiju, E.; Vijisha, M. V.; Ramesan, M. T.; Chandrasekharan, K.

2018-05-01

The enhanced nonlinear optical properties of phenothiazine-iodine (PTZ-I) charge transfer complex (CTC) on composite formation with ZnS/ZnSe nanostructures are reported. The interaction between the components was confirmed by the FTIR spectra. Structural and morphological changes on nanocomposite formation were analyzed by scanning electron microscopy and X-ray diffraction spectra. The absorption and emission features of both the nanocomposites and their constituent components were studied. Nonlinear optical properties of all the samples in nanosecond regime were investigated by the Z-scan technique using Nd: YAG laser with 532 nm wavelength and 7 ns pulse width. The optical nonlinearity of PTZ-I CTC was found to be improved considerably on composite formation and the new systems can be proposed as excellent candidates for photonic devices. Enhanced optical nonlinearity of the composites could be attributed to charge/energy transfer mechanism between PTZ-I CTC and the nanostructures.

Ultrahigh-Speed Optical Coherence Tomography for Three-Dimensional and En Face Imaging of the Retina and Optic Nerve Head

PubMed Central

Srinivasan, Vivek J.; Adler, Desmond C.; Chen, Yueli; Gorczynska, Iwona; Huber, Robert; Duker, Jay S.; Schuman, Joel S.; Fujimoto, James G.

2009-01-01

Purpose To demonstrate ultrahigh-speed optical coherence tomography (OCT) imaging of the retina and optic nerve head at 249,000 axial scans per second and a wavelength of 1060 nm. To investigate methods for visualization of the retina, choroid, and optic nerve using high-density sampling enabled by improved imaging speed. Methods A swept-source OCT retinal imaging system operating at a speed of 249,000 axial scans per second was developed. Imaging of the retina, choroid, and optic nerve were performed. Display methods such as speckle reduction, slicing along arbitrary planes, en face visualization of reflectance from specific retinal layers, and image compounding were investigated. Results High-definition and three-dimensional (3D) imaging of the normal retina and optic nerve head were performed. Increased light penetration at 1060 nm enabled improved visualization of the choroid, lamina cribrosa, and sclera. OCT fundus images and 3D visualizations were generated with higher pixel density and less motion artifacts than standard spectral/Fourier domain OCT. En face images enabled visualization of the porous structure of the lamina cribrosa, nerve fiber layer, choroid, photoreceptors, RPE, and capillaries of the inner retina. Conclusions Ultrahigh-speed OCT imaging of the retina and optic nerve head at 249,000 axial scans per second is possible. The improvement of ∼5 to 10× in imaging speed over commercial spectral/Fourier domain OCT technology enables higher density raster scan protocols and improved performance of en face visualization methods. The combination of the longer wavelength and ultrahigh imaging speed enables excellent visualization of the choroid, sclera, and lamina cribrosa. PMID:18658089

Automated Ordering System.

ERIC Educational Resources Information Center

Jones, Richard M.

1981-01-01

A computer program that utilizes an optical scanning machine is used for ordering supplies in a Louisiana school system. The program provides savings in time and labor, more accurate data, and easy-to-use reports. (Author/MLF)

All fiber optics circular-state swept source polarization-sensitive optical coherence tomography.

PubMed

Lin, Hermann; Kao, Meng-Chun; Lai, Chih-Ming; Huang, Jyun-Cin; Kuo, Wen-Chuan

2014-02-01

A swept source (SS)-based circular-state (CS) polarization-sensitive optical coherence tomography (PS-OCT) constructed entirely with polarization-maintaining fiber optics components is proposed with the experimental verification. By means of the proposed calibration scheme, bulk quarter-wave plates can be replaced by fiber optics polarization controllers to, therefore, realize an all-fiber optics CS SSPS-OCT. We also present a numerical dispersion compensation method, which can not only enhance the axial resolution, but also improve the signal-to-noise ratio of the images. We demonstrate that this compact and portable CS SSPS-OCT system with an accuracy comparable to bulk optics systems requires less stringent lens alignment and can possibly serve as a technology to realize PS-OCT instrument for clinical applications (e.g., endoscopy). The largest deviations in the phase retardation (PR) and fast-axis (FA) angle due to sample probe in the linear scanning and a rotation angle smaller than 65 deg were of the same order as those in stationary probe setups. The influence of fiber bending on the measured PR and FA is also investigated. The largest deviations of the PR were 3.5 deg and the measured FA change by ~12 to 21 deg. Finally, in vivo imaging of the human fingertip and nail was successfully demonstrated with a linear scanning probe.

Free-space wavelength-multiplexed optical scanner.

PubMed

Yaqoob, Z; Rizvi, A A; Riza, N A

2001-12-10

A wavelength-multiplexed optical scanning scheme is proposed for deflecting a free-space optical beam by selection of the wavelength of the light incident on a wavelength-dispersive optical element. With fast tunable lasers or optical filters, this scanner features microsecond domain scan setting speeds and large- diameter apertures of several centimeters or more for subdegree angular scans. Analysis performed indicates an optimum scan range for a given diffraction order and grating period. Limitations include beam-spreading effects based on the varying scanner aperture sizes and the instantaneous information bandwidth of the data-carrying laser beam.

Intraoral scanning systems - a current overview.

PubMed

Zimmermann, M; Mehl, A; Mörmann, W H; Reich, S

2015-01-01

There is no doubt today about the possibilities and potential of digital impression-taking with the aid of intraoral optical impression systems, and the past few years have seen a considerable increase in the range of optical intraoral scanners available on the market. On the strength of numerous innovations and a wider range of indications in orthodontics and implantology, intraoral scanning systems appear to be a highly promising development for the future. Digital impression-taking with intraoral scanners has already shown itself in some respects to be clearly superior to conventional impression- taking. Particularly worthy of mention is the versatile integration of digital impressions into diagnostic and treatment concepts to provide a customizable healthcare solution for the patient. It remains exciting to look forward to future developments that will allow us to observe digital impression-taking--as with other digital applications already established in everyday life--becoming firmly established in the routine of dentistry and dental technology. This article presents an overview of the benefits and limitations of digital impression-taking using intraoral scanning systems, and includes a summary of all the relevant intraoral scanners available on the market at present.

Visualization of hair follicles using high-speed optical coherence tomography based on a Fourier domain mode locking laser

NASA Astrophysics Data System (ADS)

Tsai, M.-T.; Chang, F.-Y.

2012-04-01

In this study, a swept-source optical coherence tomography (SS-OCT) system with a Fourier domain mode locking (FDML) laser is proposed for a dermatology study. The homemade FDML laser is one kind of frequency-sweeping light source, which can provide output power of >20 mW and an output spectrum of 65 nm in bandwidth centered at 1300 nm, enabling imaging with an axial resolution of 12 μm in the OCT system. To eliminate the forward scans from the laser output and insert the delayed backward scans, a Mach-Zehnder configuration is implemented. Compared with conventional frequency-sweeping light sources, the FDML laser can achieve much higher scan rates, as high as ˜240 kHz, which can provide a three-dimensional imaging rate of 4 volumes/s. Furthermore, the proposed high-speed SS-OCT system can provide three-dimensional (3D) images with reduced motion artifacts. Finally, a high-speed SS-OCT system is used to visualize hair follicles, demonstrating the potential of this technology as a tool for noninvasive diagnosis of alopecia.

Dense concentric circle scanning protocol for measuring pulsatile retinal blood flow in rats with Doppler optical coherence tomography

NASA Astrophysics Data System (ADS)

Tan, Bingyao; Hosseinaee, Zohreh; Bizheva, Kostadinka

2017-11-01

The variability in the spatial orientation of retinal blood vessels near the optic nerve head (ONH) results in imprecision of the measured Doppler angle and therefore the pulsatile blood flow (BF), when those parameters are evaluated using Doppler OCT imaging protocols based on dual-concentric circular scans. Here, we utilized a dense concentric circle scanning protocol and evaluated its precision for measuring pulsatile retinal BF in rats for different numbers of the circular scans. An spectral domain optical coherence tomography (SD-OCT) system operating in the 1060-nm spectral range with image acquisition rate of 47,000 A-scans/s was used to acquire concentric circular scans centered at the rat's ONH, with diameters ranging from 0.8 to 1.0 mm. A custom, automatic blood vessel segmentation algorithm was used to track the spatial orientation of the retinal blood vessels in three dimensions, evaluate the spatially dependent Doppler angle and calculate more accurately the axial BF for each major retinal blood vessel. Metrics such as retinal BF, pulsatility index, and resistance index were evaluated for each and all of the major retinal blood vessels. The performance of the proposed dense concentric circle scanning protocols was compared with that of the dual-circle scanning protocol. Results showed a 3.8±2.2 deg difference in the Doppler angle calculation between the two approaches, which resulted in ˜7% difference in the calculated retinal BF.

Automatic and manual segmentation of healthy retinas using high-definition optical coherence tomography.

PubMed

Golbaz, Isabelle; Ahlers, Christian; Goesseringer, Nina; Stock, Geraldine; Geitzenauer, Wolfgang; Prünte, Christian; Schmidt-Erfurth, Ursula Margarethe

2011-03-01

This study compared automatic- and manual segmentation modalities in the retina of healthy eyes using high-definition optical coherence tomography (HD-OCT). Twenty retinas in 20 healthy individuals were examined using an HD-OCT system (Carl Zeiss Meditec, Inc.). Three-dimensional imaging was performed with an axial resolution of 6 μm at a maximum scanning speed of 25,000 A-scans/second. Volumes of 6 × 6 × 2 mm were scanned. Scans were analysed using a matlab-based algorithm and a manual segmentation software system (3D-Doctor). The volume values calculated by the two methods were compared. Statistical analysis revealed a high correlation between automatic and manual modes of segmentation. The automatic mode of measuring retinal volume and the corresponding three-dimensional images provided similar results to the manual segmentation procedure. Both methods were able to visualize retinal and subretinal features accurately. This study compared two methods of assessing retinal volume using HD-OCT scans in healthy retinas. Both methods were able to provide realistic volumetric data when applied to raster scan sets. Manual segmentation methods represent an adequate tool with which to control automated processes and to identify clinically relevant structures, whereas automatic procedures will be needed to obtain data in larger patient populations. © 2009 The Authors. Journal compilation © 2009 Acta Ophthalmol.

Nonlinear optical characterization of graphite oxide thin film by open aperture Z-scan technique

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

Sreeja, V. G.; Reshmi, R.; Devasia, Sebin

In this paper we explore the structural characterization of graphite oxide powder prepared from graphite powder by oxidation via modified Hummers method. The nonlinear optical properties of the spin coated graphite oxide thin film is also explored by open aperture Z-Scan technique. Structural and physiochemical properties of the samples were investigated with the help of Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy (Raman).The results of FT-IR and Raman spectroscopy showed that the graphite is oxidized by strong oxidants and the oxygen atoms are introduced into the graphite layers forming C=C, O-H and –C-H groups. The synthesized sample has goodmore » crystalline nature with lesser defects. The nonlinear optical property of GO thin film was studied by open aperture Z-Scan technique using Q-switched Nd-Yag Laser at 532 nm. The Z-scan plot showed that the investigated GO thin film has saturable absorption behavior. The nonlinear absorption coefficient and saturation intensity were also estimated to explore its applications in Q switched mode locking laser systems.« less

Near-Field Scanning Optical Microscopy and Raman Microscopy.

NASA Astrophysics Data System (ADS)

Harootunian, Alec Tate

1987-09-01

Both a one dimensional near-field scanning optical microscope and Raman microprobe were constructed. In near -field scanning optical microscopy (NSOM) a subwavelength aperture is scanned in the near-field of the object. Radiation transmitted through the aperture is collected to form an image as the aperture scans over the object. The resolution of an NSOM system is essentially wavelength independent and is limited by the diameter of the aperture used to scan the object. NSOM was developed in an effort to provide a nondestructive in situ high spatial resolution probe while still utilizing photons at optical wavelengths. The Raman microprobe constructed provided vibrational Raman information with spatial resolution equivalent that of a conventional diffraction limited microscope. Both transmission studies and near-field diffration studies of subwavelength apertures were performed. Diffraction theories for a small aperture in an infinitely thin conducting screen, a slit in a thick conducting screen, and an aperture in a black screen were examined. All three theories indicate collimation of radiation to the size to the size of the subwavelength aperture or slit in the near-field. Theoretical calculations and experimental results indicate that light transmitted through subwavelength apertures is readily detectable. Light of wavelength 4579 (ANGSTROM) was transmitted through apertures with diameters as small as 300 (ANGSTROM). These studies indicate the feasibility of constructing an NSOM system. One dimensional transmission and fluorescence NSOM systems were constructed. Apertures in the tips of metallized glass pipettes width inner diameters of less than 1000 (ANGSTROM) were used as a light source in the NSOM system. A tunneling current was used to maintain the aperture position in the near-field. Fluorescence NSOM was demonstrated for the first time. Microspectroscopic and Raman microscopic studies of turtle cone oil droplets were performed. Both the Raman vibrational frequencies and the Raman excitation data indicate that the carotenoids are unaggregated. The carotenoid astaxanthin was identified in the orange and red droplets by Raman microscopy. Future applications for both Raman microscopy and near-field microscopy were proposed. Four methods of near-field distance regulation were also examined. Finally, theoretical exposure curves for near-field lithography were calculated. Both the near-field lithographic results and the near field diffraction studies indicate essentially wavelength independent resolution. (Abstract shortened with permission of author.).

Method for producing damage resistant optics

DOEpatents

Hackel, Lloyd A.; Burnham, Alan K.; Penetrante, Bernardino M.; Brusasco, Raymond M.; Wegner, Paul J.; Hrubesh, Lawrence W.; Kozlowski, Mark R.; Feit, Michael D.

2003-01-01

The present invention provides a system that mitigates the growth of surface damage in an optic. Damage to the optic is minimally initiated. In an embodiment of the invention, damage sites in the optic are initiated, located, and then treated to stop the growth of the damage sites. The step of initiating damage sites in the optic includes a scan of the optic using a laser to initiate defects. The exact positions of the initiated sites are identified. A mitigation process is performed that locally or globally removes the cause of subsequent growth of the damaged sites.

75 FR 13486 - Application(s) for Duty-Free Entry of Scientific Instruments

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-22

... nanostructures. This instrument combines an optical microscope with a scanning probe imaging system. Specifically... soft materials than other instruments, as it detects the probe coming close to the sample surface by... conventional AFM type silicon cantilevers as well as cantilevered optical fiber probes with exposed probe...

An Introduction to PunchScan

NASA Astrophysics Data System (ADS)

Popoveniuc, Stefan; Hosp, Ben

PunchScan is a precinct-read optical-scan balloting system that allows voters to take their ballot with them after scanning. This does not violate the secret ballot principle because the ballots cannot be read without secret information held by the distributed authority in charge of the election. In fact, this election authority will publish the ballots for everyone to see, allowing voters whose ballots were incorrectly omitted to complain. PunchScan vote-counting is performed in private by the election authority - who uses their secret information to decode the ballots - but is verified in public by an auditor.In this paper we describe how and why PunchScan works. We have kept most of the description at an outline level so that it may be used as a straw model of a cryptographic voting system.

WE-D-17A-02: Evaluation of a Two-Dimensional Optical Dosimeter On Measuring Lateral Profiles of Proton Pencil Beams

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

Hsi, W; Lee, T; Schultz, T

Purpose: To evaluate the accuracy of a two-dimensional optical dosimeter on measuring lateral profiles for spots and scanned fields of proton pencil beams. Methods: A digital camera with a color image senor was utilized to image proton-induced scintillations on Gadolinium-oxysulfide phosphor reflected by a stainless-steel mirror. Intensities of three colors were summed for each pixel with proper spatial-resolution calibration. To benchmark this dosimeter, the field size and penumbra for 100mm square fields of singleenergy pencil-scan protons were measured and compared between this optical dosimeter and an ionization-chamber profiler. Sigma widths of proton spots in air were measured and compared betweenmore » this dosimeter and a commercial optical dosimeter. Clinical proton beams with ranges between 80 mm and 300 mm at CDH proton center were used for this benchmark. Results: Pixel resolutions vary 1.5% between two perpendicular axes. For a pencil-scan field with 302 mm range, measured field sizes and penumbras between two detection systems agreed to 0.5 mm and 0.3 mm, respectively. Sigma widths agree to 0.3 mm between two optical dosimeters for a proton spot with 158 mm range; having widths of 5.76 mm and 5.92 mm for X and Y axes, respectively. Similar agreements were obtained for others beam ranges. This dosimeter was successfully utilizing on mapping the shapes and sizes of proton spots at the technical acceptance of McLaren proton therapy system. Snow-flake spots seen on images indicated the image sensor having pixels damaged by radiations. Minor variations in intensity between different colors were observed. Conclusions: The accuracy of our dosimeter was in good agreement with other established devices in measuring lateral profiles of pencil-scan fields and proton spots. A precise docking mechanism for camera was designed to keep aligned optical path while replacing damaged image senor. Causes for minor variations between emitted color lights will be investigated.« less

Accuracy of parameter estimates for closely spaced optical targets using multiple detectors

NASA Astrophysics Data System (ADS)

Dunn, K. P.

1981-10-01

In order to obtain the cross-scan position of an optical target, more than one scanning detector is used. As expected, the cross-scan position estimation performance degrades when two nearby optical targets interfere with each other. Theoretical bounds on the two-dimensional parameter estimation performance for two closely spaced optical targets are found. Two particular classes of scanning detector arrays, namely, the crow's foot and the brickwall (or mosaic) patterns, are considered.

Note: A resonating reflector-based optical system for motion measurement in micro-cantilever arrays

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

Sathishkumar, P.; Punyabrahma, P.; Sri Muthu Mrinalini, R.

A robust, compact optical measurement unit for motion measurement in micro-cantilever arrays enables development of portable micro-cantilever sensors. This paper reports on an optical beam deflection-based system to measure the deflection of micro-cantilevers in an array that employs a single laser source, a single detector, and a resonating reflector to scan the measurement laser across the array. A strategy is also proposed to extract the deflection of individual cantilevers from the acquired data. The proposed system and measurement strategy are experimentally evaluated and demonstrated to measure motion of multiple cantilevers in an array.

Adaptive optimization of reference intensity for optical coherence imaging using galvanometric mirror tilting method

NASA Astrophysics Data System (ADS)

Kim, Ji-hyun; Han, Jae-Ho; Jeong, Jichai

2015-09-01

Integration time and reference intensity are important factors for achieving high signal-to-noise ratio (SNR) and sensitivity in optical coherence tomography (OCT). In this context, we present an adaptive optimization method of reference intensity for OCT setup. The reference intensity is automatically controlled by tilting a beam position using a Galvanometric scanning mirror system. Before sample scanning, the OCT system acquires two dimensional intensity map with normalized intensity and variables in color spaces using false-color mapping. Then, the system increases or decreases reference intensity following the map data for optimization with a given algorithm. In our experiments, the proposed method successfully corrected the reference intensity with maintaining spectral shape, enabled to change integration time without manual calibration of the reference intensity, and prevented image degradation due to over-saturation and insufficient reference intensity. Also, SNR and sensitivity could be improved by increasing integration time with automatic adjustment of the reference intensity. We believe that our findings can significantly aid in the optimization of SNR and sensitivity for optical coherence tomography systems.

High speed, wide velocity dynamic range Doppler optical coherence tomography (Part III): in vivo endoscopic imaging of blood flow in the rat and human gastrointestinal tracts

NASA Astrophysics Data System (ADS)

Yang, Victor X. D.; Gordon, Maggie L.; Tang, Shou-Jiang; Marcon, Norman E.; Gardiner, Geoffrey; Qi, Bing; Bisland, Stuart; Seng-Yue, Emily; Lo, Stewart; Pekar, Julius; Wilson, Brian C.; Vitkin, I. Alex

2003-09-01

We previously described a fiber based Doppler optical coherence tomography system [1] capable of imaging embryo cardiac blood flow at 4~16 frames per second with wide velocity dynamic range [2]. Coupling this system to a linear scanning fiber optical catheter design that minimizes friction and vibrations, we report here the initial results of in vivo endoscopic Doppler optical coherence tomography (EDOCT) imaging in normal rat and human esophagus. Microvascular flow in blood vessels less than 100 µm diameter was detected using a combination of color-Doppler and velocity variance imaging modes, during clinical endoscopy using a mobile EDOCT system.

The branching ratio K → ev/K → μv: A test of V-A theory of weak interactions

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

McReynolds, John Frederick

1970-09-16

An optical spark chamber experiment utilizing an axially focusing cylindrically symmetric spectrometer and limits were stopped on the spectrometer axis. Events were scanned and measured on SASS, an automatic scanning system. A total of 150, 000 events were measured, analyzed,and kinematically reconstructed.

Panoramic attitude sensor for Radio Astronomy Explorer B

NASA Technical Reports Server (NTRS)

Thomsen, R.

1973-01-01

An instrument system to acquire attitude determination data for the RAE-B spacecraft was designed and built. The system consists of an electronics module and two optical scanner heads. Each scanner head has an optical scanner with a field of view of 0.7 degrees diameter which scans the sky and measures the position of the moon, earth and sun relative to the spacecraft. This scanning is accomplished in either of two modes. When the spacecraft is spinning, the scanner operates in spherical mode, with the spacecraft spin providing the slow sweep of lattitude to scan the entire sky. After the spacecraft is placed in lunar orbit and despun, the scanner will operate in planar mode, advancing at a rate of 5.12 seconds per revolution in a fixed plane parallel to the spacecraft Z axis. This scan will cross and measure the moon horizons with every revolution. Each scanner head also has a sun slit which is aligned parallel to the spin axis of the spacecraft and which provides a sun pulse each revolution of the spacecraft. The electronics module provides the command and control, data processing and housekeeping functions.

Nonlinear optical investigation of the Tris(2‧,2-bipyridyl)iron(II) tetrafluoroborate using z-scan technique

NASA Astrophysics Data System (ADS)

Zidan, M. D.; Al-Ktaifani, M. M.; Allahham, A.

2017-05-01

Z-scan measurements were performed with a CW diode laser at 635 nm to investigate the nonlinear optical properties of Tris(2‧,2-bipyridyl)iron(II) tetrafluoroborate in ethanol at two concentrations. Theoretical fit was carried out to evaluate the nonlinear absorption coefficient (β) and the negative nonlinear refractive index (n2) for the studied complex. Furthermore, the ground-state absorption cross sections (σg), the excited-state absorption cross sections (σex) and thermo-optic coefficient were also estimated. The investigations show large NLO response, which is predominantly associated with substantial conjugation between the aromatic ring π-electron system and d-electron set metal center. The obtained results give a strong indication that Tris(2‧,2-bipyridyl)iron(II) tetrafluoroborate have a potential application in optical domain.

Three-dimensional ophthalmic optical coherence tomography with a refraction correction algorithm

NASA Astrophysics Data System (ADS)

Zawadzki, Robert J.; Leisser, Christoph; Leitgeb, Rainer; Pircher, Michael; Fercher, Adolf F.

2003-10-01

We built an optical coherence tomography (OCT) system with a rapid scanning optical delay (RSOD) line, which allows probing full axial eye length. The system produces Three-dimensional (3D) data sets that are used to generate 3D tomograms of the model eye. The raw tomographic data were processed by an algorithm, which is based on Snell"s law to correct the interface positions. The Zernike polynomials representation of the interfaces allows quantitative wave aberration measurements. 3D images of our results are presented to illustrate the capabilities of the system and the algorithm performance. The system allows us to measure intra-ocular distances.

Through-focus scanning optical microscopy (TSOM) with adaptive optics

NASA Astrophysics Data System (ADS)

Lee, Jun Ho; Park, Gyunam; Jeong, Junhee; Park, Chris

2018-03-01

Through-focus optical microscopy (TSOM) with nanometer-scale lateral and vertical sensitivity levels matching those of scanning electron microscopy has been demonstrated to be useful both for 3D inspections and metrology assessments. In 2014, funded by two private companies (Nextin/Samsung Electronics) and the Korea Evaluation Institute of Industrial Technology (KEIT), a research team from four universities in South Korea set out to investigate core technologies for developing in-line TSOM inspection and metrology tools, with the respective teams focusing on optics implementation, defect inspection, computer simulation and high-speed metrology matching. We initially confirmed the reported validity of the TSOM operation through a computer simulation, after which we implemented the TSOM operation by throughfocus scanning of existing UV (355nm) and IR (800nm) inspection tools. These tools have an identical sampling distance of 150 nm but have different resolving distances (310 and 810 nm, respectively). We initially experienced some improvement in the defect inspection sensitivity level over TSV (through-silicon via) samples with 6.6 μm diameters. However, during the experiment, we noted sensitivity and instability issues when attempting to acquire TSOM images. As TSOM 3D information is indirectly extracted by differentiating a target TSOM image from reference TSOM images, any instability or mismatch in imaging conditions can result in measurement errors. As a remedy to such a situation, we proposed the application of adaptive optics to the TSOM operation and developed a closed-loop system with a tip/tilt mirror and a Shack-Hartmann sensor on an optical bench. We were able to keep the plane position within in RMS 0.4 pixel by actively compensating for any position instability which arose during the TSOM scanning process along the optical axis. Currently, we are also developing another TSOM tool with a deformable mirror instead of a tip/tilt mirror, in which case we will not require any mechanical scanning.

Development of a patient-specific 3D dose evaluation program for QA in radiation therapy

NASA Astrophysics Data System (ADS)

Lee, Suk; Chang, Kyung Hwan; Cao, Yuan Jie; Shim, Jang Bo; Yang, Dae Sik; Park, Young Je; Yoon, Won Sup; Kim, Chul Yong

2015-03-01

We present preliminary results for a 3-dimensional dose evaluation software system ( P DRESS, patient-specific 3-dimensional dose real evaluation system). Scanned computed tomography (CT) images obtained by using dosimetry were transferred to the radiation treatment planning system (ECLIPSE, VARIAN, Palo Alto, CA) where the intensity modulated radiation therapy (IMRT) nasopharynx plan was designed. We used a 10 MV photon beam (CLiX, VARIAN, Palo Alto, CA) to deliver the nasopharynx treatment plan. After irradiation, the TENOMAG dosimeter was scanned using a VISTA ™ scanner. The scanned data were reconstructed using VistaRecon software to obtain a 3D dose distribution of the optical density. An optical-CT scanner was used to readout the dose distribution in the gel dosimeter. Moreover, we developed the P DRESS by using Flatform, which were developed by our group, to display the 3D dose distribution by loading the DICOM RT data which are exported from the radiotherapy treatment plan (RTP) and the optical-CT reconstructed VFF file, into the independent P DRESS with an ioniz ation chamber and EBT film was used to compare the dose distribution calculated from the RTP with that measured by using a gel dosimeter. The agreement between the normalized EBT, the gel dosimeter and RTP data was evaluated using both qualitative and quantitative methods, such as the isodose distribution, dose difference, point value, and profile. The profiles showed good agreement between the RTP data and the gel dosimeter data, and the precision of the dose distribution was within ±3%. The results from this study showed significantly discrepancies between the dose distribution calculated from the treatment plan and the dose distribution measured by a TENOMAG gel and by scanning with an optical CT scanner. The 3D dose evaluation software system ( P DRESS, patient specific dose real evaluation system), which were developed in this study evaluates the accuracies of the three-dimensional dose distributions. Further applications of the system utility are expected to result from future studies.

MO-F-CAMPUS-T-04: Utilization of Optical Dosimeter for Modulated Spot-Scanning Particle Beam

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

Hsi, W; Li, Y; Huang, Z

Purpose: To present the utilization of an optical dosimeter for modulated spot-scanning carbon-ion and proton beams during the acceptance test of Siemens IONTRIS system. Method and Materials: An optical dosimeter using phosphor scintillation was developed to map and interactively analyze the shapes and sizes of spots over 190 energies for ProTom modulated-scanning system. The dose response to proton had been characterized with proper pixel calibration at ProTom system. The dose response was further studied at 0.7 cm depths by uniform 8cm in-diameter fields of 424.89 MeV/u (E290) carbon-ions and 215.18MeV (E282) protons at IONTRIS system. The virtual source axial distancesmore » (vSAD) of carbonions and protons of IONTRIS system was investigated by measuring either variations of spot position or field size at five different locations to Isocenter. By measuring lateral profiles of uniform doses with varied thin-thicknesses of chest-board pattern and placing the scintillation plate at near to the distal edge, range variations at different off-axis-distances (rOAD) were examined. Relative accuracy and reproducibility of beam range were measured for three beam ranges with a ramping block at front of scintillation plate. Results: Similar dose response was observed for high energies of carbon ions and protons. Mean vSAD at X and Y axes were 744.1 cm and 807.4cm with deviation of 7.4cm and 7.7cm, respectively. Variation of rOAD was within 0.35 mm over 10cm for both protons and carbon ions. Accuracy of measuring relative distal range using the ramping block was 0.2mm. Measured range over repeated three times for each range were within 0.25mm at same room, and within 1.0mm between four rooms. Conclusions: The optical dosimeter could efficiently measure the virtual source distance. And, to measure small range variation at different off-axial locations, and for the relative beam range between rooms during acceptance test of a modulated spot-scanning particle system.« less

Optical frequency switching scheme for a high-speed broadband THz measurement system based on the photomixing technique.

PubMed

Song, Hajun; Hwang, Sejin; Song, Jong-In

2017-05-15

This study presents an optical frequency switching scheme for a high-speed broadband terahertz (THz) measurement system based on the photomixing technique. The proposed system can achieve high-speed broadband THz measurements using narrow optical frequency scanning of a tunable laser source combined with a wavelength-switchable laser source. In addition, this scheme can provide a larger output power of an individual THz signal compared with that of a multi-mode THz signal generated by multiple CW laser sources. A swept-source THz tomography system implemented with a two-channel wavelength-switchable laser source achieves a reduced time for acquisition of a point spread function and a higher depth resolution in the same amount of measurement time compared with a system with a single optical source.

A digital transducer and digital microphone using an optical technique

NASA Astrophysics Data System (ADS)

Ghelmansarai, F. A.

1996-09-01

A transducer is devised to measure pressure, displacements or angles by optical means. This transducer delivers a digital output without relying on interferometry techniques or analogue-to-digital converters. This device is based on an optical scanner and an optical detector. An inter-digital photoconductive detector (IDPC) is employed that delivers a series of pulses, whose number depends on the scan length. A pre-objective scanning configuration is used that allows for the possibility of a flat image plane. The optical scanner provides scanning of IDPC and the generated scan length is proportional to the measurand.

Calculation of the overlap factor for scanning LiDAR based on the tridimensional ray-tracing method.

PubMed

Chen, Ruiqiang; Jiang, Yuesong; Wen, Luhong; Wen, Donghai

2017-06-01

The overlap factor is used to evaluate the LiDAR light collection ability. Ranging LiDAR is mainly determined by the optical configuration. However, scanning LiDAR, equipped with a scanning mechanism to acquire a 3D coordinate points cloud for a specified target, is essential in considering the scanning effect at the same time. Otherwise, scanning LiDAR will reduce the light collection ability and even cannot receive any echo. From this point of view, we propose a scanning LiDAR overlap factor calculation method based on the tridimensional ray-tracing method, which can be applied to scanning LiDAR with any special laser intensity distribution, any type of telescope (reflector, refractor, or mixed), and any shape obstruction (i.e., the reflector of a coaxial optical system). A case study for our LiDAR with a scanning mirror is carried out, and a MATLAB program is written to analyze the laser emission and reception process. Sensitivity analysis is carried out as a function of scanning mirror rotation speed and detector position, and the results guide how to optimize the overlap factor for our LiDAR. The results of this research will have a guiding significance in scanning LiDAR design and assembly.

[Research on lateral shearing interferometer for field monitoring of natural gas pipeline leak].

PubMed

Zhang, Xue-Feng; Gao, Yu-Bin

2012-09-01

Aimed at the mechanical scanning spectroscopy equipment with poor anti-interference and anti-jamming ability, which affects the accuracy of its natural gas pipeline leak detection in the wild, a new type of lateral shearing interferometer system was designed. The system uses a beam splitter to get optical path difference by a mechanical scanning part, and it cancel the introduction of external vibration interference through the linkage between the two beam splitterw. The interference intensity of interference fringes produced was calculated, and analysis of a rotating beam splitter corresponds to the angle of the optical path difference function, solving for the maximum angle of the forward rotation and reverse rotation, which is the maximum optical path range. Experiments using the gas tank deflated simulated natural gas pipeline leak process, in the interference conditions, and the test data of the type WQF530 spectrometer and the new type of lateral shearing interferometer system were comparedt. The experimental results show that the relative error of both systems is about 1% in indoor conditions without interference. However, in interference environment, the error of WQF530 type spectrometer becomes larger, more than 10%, but the error of the new type of lateral shearing interferometer system is still below 5%. The detection accuracy of the type WQF530 spectrometer decreased significantly due to the environment. Therefore, the seismic design of the system can effectively offset power deviation and half-width increases of center wavelength caused by external interference, and compared to conventional mechanical scanning interferometer devices the new system is more suitable for field detection.

Study of multi-channel optical system based on the compound eye

NASA Astrophysics Data System (ADS)

Zhao, Yu; Fu, Yuegang; Liu, Zhiying; Dong, Zhengchao

2014-09-01

As an important part of machine vision, compound eye optical systems have the characteristics of high resolution and large FOV. By applying the compound eye optical systems to target detection and recognition, the contradiction between large FOV and high resolution in the traditional single aperture optical systems could be solved effectively and also the parallel processing ability of the optical systems could be sufficiently shown. In this paper, the imaging features of the compound eye optical systems are analyzed. After discussing the relationship between the FOV in each subsystem and the contact ratio of the FOV in the whole system, a method to define the FOV of the subsystem is presented. And a compound eye optical system is designed, which is based on the large FOV synthesized of multi-channels. The compound eye optical system consists with a central optical system and array subsystem, in which the array subsystem is used to capture the target. The high resolution image of the target could be achieved by the central optical system. With the advantage of small volume, light weight and rapid response speed, the optical system could detect the objects which are in 3km and FOV of 60°without any scanning device. The objects in the central field 2w=5.1°could be imaged with high resolution so that the objects could be recognized.

Dual-wavelength photothermal optical coherence tomography for blood oxygen saturation measurement

NASA Astrophysics Data System (ADS)

Yin, Biwei; Kuranov, Roman V.; McElroy, Austin B.; Milner, Thomas E.

2013-03-01

We report design and demonstration of a dual wavelength photothermal (DWP) optical coherence tomography (OCT) system for imaging of a phantom microvessel and measurement of hemoglobin oxygen saturation (SO2) level. The DWP-OCT system contains a swept-source (SS) two-beam phase-sensitive (PhS) OCT system (1060 nm) and two intensity modulated photothermal excitation lasers (770 nm and 800 nm). The PhS-OCT probe beam (1060 nm) and photothermal excitation beams are combined into one single-mode optical fiber. A galvanometer based two-dimensional achromatic scanning system is designed to provide 14 μm lateral resolution for the PhS-OCT probe beam (1060 nm) and 13 μm lateral resolution for photothermal excitation beams. DWP-OCT system's sensitivity is 102 dB, axial resolution is 13 μm in tissue and uses a real-time digital dispersion compensation algorithm. Noise floor for optical pathlength measurements is 300 pm in the signal frequency range (380-400 Hz) of photothermal modulation frequencies. Blood SO2 level is calculated from measured optical pathlength (op) signal in a 300 μm diameter microvessel phantom introduced by the two photothermal excitation beams. En-face and B-scan images of a phantom microvessel are recorded, and six blood samples' SO2 levels are measured using DWP-OCT and compared with values provided by a commercial blood oximeter. A mathematical model indicates thermal diffusion introduces a systematic artifact that over-estimates SO2 values and is consistent with measured data.

Quantitative, simultaneous, and collinear eye-tracked, high dynamic range optical coherence tomography at 850 and 1060 nm

NASA Astrophysics Data System (ADS)

Mooser, Matthias; Burri, Christian; Stoller, Markus; Luggen, David; Peyer, Michael; Arnold, Patrik; Meier, Christoph; Považay, Boris

2017-07-01

Ocular optical coherence tomography at the wavelengths ranges of 850 and 1060 nm have been integrated with a confocal scanning laser ophthalmoscope eye-tracker as a clinical commercial-class system. Collinear optics enables an exact overlap of the different channels to produce precisely overlapping depth-scans for evaluating the similarities and differences between the wavelengths to extract additional physiologic information. A reliable segmentation algorithm utilizing Graphcuts has been implemented and applied to automatically extract retinal and choroidal shape in cross-sections and volumes. The device has been tested in normals and pathologies including a cross-sectional and longitudinal study of myopia progress and control with a duplicate instrument in Asian children.

Feasibility study of a synthesis procedure for array feeds to improve radiation performance of large distorted reflector antennas

NASA Technical Reports Server (NTRS)

Stutzman, W. L.; Takamizawa, K.; Werntz, P.; Lapean, J.; Barts, R.

1991-01-01

The following subject areas are covered: General Reflector Antenna Systems Program version 7(GRASP7); Multiple Reflector Analysis Program for Cylindrical Antennas (MRAPCA); Tri-Reflector 2D Synthesis Code (TRTDS); a geometrical optics and a physical optics synthesis techniques; beam scanning reflector, the type 2 and 6 reflectors, spherical reflector, and multiple reflector imaging systems; and radiometric array design.

REPRODUCIBILITY OF VESSEL DENSITY MEASUREMENT WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN EYES WITH AND WITHOUT RETINOPATHY.

PubMed

You, Qisheng; Freeman, William R; Weinreb, Robert N; Zangwill, Linda; Manalastas, Patricia I C; Saunders, Luke J; Nudleman, Eric

2017-08-01

To determine the intravisit and intervisit reproducibility of optical coherence tomography angiography measurements of macular vessel density in eyes with and without retinal diseases. Fifteen healthy volunteers and 22 patients with retinal diseases underwent repeated optical coherence tomography angiography (Angiovue Imaging System, Optovue Inc) scans after pupil dilation on 2 separate visit days. For each visit day, the eyes were scanned twice. Vessel density defined as the proportion of vessel area with flowing blood over the total measurement area was calculated using Angiovue software. Intravisit and intervisit reproducibility were summarized as coefficient of variations and intraclass correlation coefficients were calculated from variance component models. The coefficient of variations representing the intravisit reproducibility of the superficial macular vessel density measurements for different quadrants on 3 mm × 3-mm scans varied from 2.1% to 4.9% and 3.4% to 6.8% for healthy and diseased eyes, respectively, and for the intervisit it was 2.9% to 5.1% and 4.0% to 6.8%, respectively. The coefficient of variations were lower in healthy eyes than in diseased eyes, lower for intravisit than for intervisit, lower on 3 mm × 3-mm scans than on 6 mm × 6-mm scans, and lower for paracentral subfields than for central subfield. The evidence presented here demonstrates good reproducibility of optical coherence tomography angiography for measurement of superficial macula vessel density in both healthy eyes and eyes with diabetic retinopathy without diabetic macular edema.

Corneal thickness and elevation measurements using swept-source optical coherence tomography and slit scanning topography in normal and keratoconic eyes.

PubMed

Jhanji, Vishal; Yang, Bingzhi; Yu, Marco; Ye, Cong; Leung, Christopher K S

2013-11-01

To compare corneal thickness and corneal elevation using swept source optical coherence tomography and slit scanning topography. Prospective study. 41 normal and 46 keratoconus subjects. All eyes were imaged using swept source optical coherence tomography and slit scanning tomography during the same visit. Mean corneal thickness and best-fit sphere measurements were compared between the instruments. Agreement of measurements between swept source optical coherence tomography and scanning slit topography was analyzed. Intra-rater reproducibility coefficient and intraclass correlation coefficient were evaluated. In normal eyes, central corneal thickness measured by swept source optical coherence tomography was thinner compared with slit scanning topography (p < 0.0001) and ultrasound pachymetry (p = < .0001). Ultrasound pachymetry readings had better 95% limits of agreement with swept source optical coherence tomography than slit scanning topography. In keratoconus eyes, central corneal thickness was thinner on swept source optical coherence tomography than slit scanning topography (p = 0.081) and ultrasound pachymetry (p = 0.001). There were significant differences between thinnest corneal thickness, and, anterior and posterior best-fit sphere measurements between both instruments (p < 0.05 for all). Overall, reproducibility coefficients and intraclass correlation coefficients were significantly better with swept source optical coherence tomography for measurement of central corneal thickness, anterior best-fit sphere and, posterior best-fit sphere (all p < 0.001). Corneal thickness and elevation measurements were significantly different between swept source optical coherence tomography and slit scanning topography. With better reproducibility coefficients and intraclass correlation coefficients, swept source optical coherence tomography may provide a reliable alternative for measurement of corneal parameters. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

Towards combined optical coherence tomography and hyper-spectral imaging for gastrointestinal endoscopy

NASA Astrophysics Data System (ADS)

Attendu, Xavier; Crunelle, Camille; de Sivry-Houle, Martin Poinsinet; Maubois, Billie; Urbain, Joanie; Turrell, Chloe; Strupler, Mathias; Godbout, Nicolas; Boudoux, Caroline

2018-04-01

Previous works have demonstrated feasibility of combining optical coherence tomography (OCT) and hyper-spectral imaging (HSI) through a single double-clad fiber (DCF). In this proceeding we present the continued development of a system combining both modalities and capable of rapid imaging. We discuss the development of a rapidly scanning, dual-band, polygonal swept-source system which combines NIR (1260-1340 nm) and visible (450-800 nm) wavelengths. The NIR band is used for OCT imaging while visible light allows HSI. Scanning rates up to 24 kHz are reported. Furthermore, we present and discuss the fiber system used for light transport, delivery and collection, and the custom signal acquisition software. Key points include the use of a double-clad fiber coupler as well as important alignments and back-reflection management. Simultaneous and co-registered imaging with both modalities is presented in a bench-top system

Identification of nanoparticles and nanosystems in biological matrices with scanning probe microscopy.

PubMed

Angeloni, Livia; Reggente, Melania; Passeri, Daniele; Natali, Marco; Rossi, Marco

2018-04-17

Identification of nanoparticles and nanosystems into cells and biological matrices is a hot research topic in nanobiotechnologies. Because of their capability to map physical properties (mechanical, electric, magnetic, chemical, or optical), several scanning probe microscopy based techniques have been proposed for the subsurface detection of nanomaterials in biological systems. In particular, atomic force microscopy (AFM) can be used to reveal stiff nanoparticles in cells and other soft biomaterials by probing the sample mechanical properties through the acquisition of local indentation curves or through the combination of ultrasound-based methods, like contact resonance AFM (CR-AFM) or scanning near field ultrasound holography. Magnetic force microscopy can detect magnetic nanoparticles and other magnetic (bio)materials in nonmagnetic biological samples, while electric force microscopy, conductive AFM, and Kelvin probe force microscopy can reveal buried nanomaterials on the basis of the differences between their electric properties and those of the surrounding matrices. Finally, scanning near field optical microscopy and tip-enhanced Raman spectroscopy can visualize buried nanostructures on the basis of their optical and chemical properties. Despite at a still early stage, these methods are promising for detection of nanomaterials in biological systems as they could be truly noninvasive, would not require destructive and time-consuming specific sample preparation, could be performed in vitro, on alive samples and in water or physiological environment, and by continuously imaging the same sample could be used to dynamically monitor the diffusion paths and interaction mechanisms of nanomaterials into cells and biological systems. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Nanotechnology Approaches to Biology > Nanoscale Systems in Biology. © 2018 Wiley Periodicals, Inc.

Optical architecture design for detection of absorbers embedded in visceral fat.

PubMed

Francis, Robert; Florence, James; MacFarlane, Duncan

2014-05-01

Optically absorbing ducts embedded in scattering adipose tissue can be injured during laparoscopic surgery. Non-sequential simulations and theoretical analysis compare optical system configurations for detecting these absorbers. For absorbers in deep scattering volumes, trans-illumination is preferred instead of diffuse reflectance. For improved contrast, a scanning source with a large area detector is preferred instead of a large area source with a pixelated detector.

Optical architecture design for detection of absorbers embedded in visceral fat

PubMed Central

Francis, Robert; Florence, James; MacFarlane, Duncan

2014-01-01

Optically absorbing ducts embedded in scattering adipose tissue can be injured during laparoscopic surgery. Non-sequential simulations and theoretical analysis compare optical system configurations for detecting these absorbers. For absorbers in deep scattering volumes, trans-illumination is preferred instead of diffuse reflectance. For improved contrast, a scanning source with a large area detector is preferred instead of a large area source with a pixelated detector. PMID:24877008

(Full field) optical coherence tomography and applications

NASA Astrophysics Data System (ADS)

Buchroithner, Boris; Hannesschläger, Günther; Leiss-Holzinger, Elisabeth; Prylepa, Andrii; Heise, Bettina

2018-03-01

This paper illustrates specific features and use of optical coherence tomography (OCT) in the raster-scanning and in comparison in the full field version of this imaging technique. Cases for nondestructive testing are discussed alongside other application schemes. In particular monitoring time-dependent processes and probing of birefringent specimens are considered here. In the context of polymer testing birefringence mapping may often provide information about internal strain and stress states. Recent results obtained with conventional raster-scanning OCT systems, with (dual and single-shot) full field OCT configurations, and with polarization-sensitive versions of (full field) OCT are presented here.

Design and Simulation of Scanner Wrapped by Flexible Microcoil Embedded in Polymer Film for Single-Optical Endoscope Application

NASA Astrophysics Data System (ADS)

Zhao, Mengyuan; Yang, Zhuoqing; Xiang, Xiaojian; Sun, Bin; Ding, Guifu; Zhao, Xiaolin

2018-03-01

A single optic fiber scanner with large scanning angle, based on novel electromagnetic driven, is presented. The cylinder magnet and weight are fixed on the fiber, and vibrate under its second-order frequency by driving racetrack coils on the tube. The flexible driving coil is fabricated by uncomplicated planar MEMS technology on polyimide film, and wrapped on the tube. The electromagnetic and mechanical properties of the endoscope system are studied. Experimental results show that the maximum of the second resonant scanning angle is 9.47°.

Calibration for single multi-mode fiber digital scanning microscopy imaging system

NASA Astrophysics Data System (ADS)

Yin, Zhe; Liu, Guodong; Liu, Bingguo; Gan, Yu; Zhuang, Zhitao; Chen, Fengdong

2015-11-01

Single multimode fiber (MMF) digital scanning imaging system is a development tendency of modern endoscope. We concentrate on the calibration method of the imaging system. Calibration method comprises two processes, forming scanning focused spots and calibrating the couple factors varied with positions. Adaptive parallel coordinate algorithm (APC) is adopted to form the focused spots at the multimode fiber (MMF) output. Compare with other algorithm, APC contains many merits, i.e. rapid speed, small amount calculations and no iterations. The ratio of the optics power captured by MMF to the intensity of the focused spots is called couple factor. We setup the calibration experimental system to form the scanning focused spots and calculate the couple factors for different object positions. The experimental result the couple factor is higher in the center than the edge.

Improved Scanners for Microscopic Hyperspectral Imaging

NASA Technical Reports Server (NTRS)

Mao, Chengye

2009-01-01

Improved scanners to be incorporated into hyperspectral microscope-based imaging systems have been invented. Heretofore, in microscopic imaging, including spectral imaging, it has been customary to either move the specimen relative to the optical assembly that includes the microscope or else move the entire assembly relative to the specimen. It becomes extremely difficult to control such scanning when submicron translation increments are required, because the high magnification of the microscope enlarges all movements in the specimen image on the focal plane. To overcome this difficulty, in a system based on this invention, no attempt would be made to move either the specimen or the optical assembly. Instead, an objective lens would be moved within the assembly so as to cause translation of the image at the focal plane: the effect would be equivalent to scanning in the focal plane. The upper part of the figure depicts a generic proposed microscope-based hyperspectral imaging system incorporating the invention. The optical assembly of this system would include an objective lens (normally, a microscope objective lens) and a charge-coupled-device (CCD) camera. The objective lens would be mounted on a servomotor-driven translation stage, which would be capable of moving the lens in precisely controlled increments, relative to the camera, parallel to the focal-plane scan axis. The output of the CCD camera would be digitized and fed to a frame grabber in a computer. The computer would store the frame-grabber output for subsequent viewing and/or processing of images. The computer would contain a position-control interface board, through which it would control the servomotor. There are several versions of the invention. An essential feature common to all versions is that the stationary optical subassembly containing the camera would also contain a spatial window, at the focal plane of the objective lens, that would pass only a selected portion of the image. In one version, the window would be a slit, the CCD would contain a one-dimensional array of pixels, and the objective lens would be moved along an axis perpendicular to the slit to spatially scan the image of the specimen in pushbroom fashion. The image built up by scanning in this case would be an ordinary (non-spectral) image. In another version, the optics of which are depicted in the lower part of the figure, the spatial window would be a slit, the CCD would contain a two-dimensional array of pixels, the slit image would be refocused onto the CCD by a relay-lens pair consisting of a collimating and a focusing lens, and a prism-gratingprism optical spectrometer would be placed between the collimating and focusing lenses. Consequently, the image on the CCD would be spatially resolved along the slit axis and spectrally resolved along the axis perpendicular to the slit. As in the first-mentioned version, the objective lens would be moved along an axis perpendicular to the slit to spatially scan the image of the specimen in pushbroom fashion.

Evaluation of Retinal and Choroidal Thickness by Swept-Source Optical Coherence Tomography: Repeatability and Assessment of Artifacts

PubMed Central

Mansouri, Kaweh; Medeiros, Felipe A.; Tatham, Andrew J.; Marchase, Nicholas; Weinreb, Robert N.

2017-01-01

PURPOSE To determine the repeatability of automated retinal and choroidal thickness measurements with swept-source optical coherence tomography (SS OCT) and the frequency and type of scan artifacts. DESIGN Prospective evaluation of new diagnostic technology. METHODS Thirty healthy subjects were recruited prospectively and underwent imaging with a prototype SS OCT instrument. Undilated scans of 54 eyes of 27 subjects (mean age, 35.1 ± 9.3 years) were obtained. Each subject had 4 SS OCT protocols repeated 3 times: 3-dimensional (3D) 6 × 6-mm raster scan of the optic disc and macula, radial, and line scan. Automated measurements were obtained through segmentation software. Interscan repeatability was assessed by intraclass correlation coefficients (ICCs). RESULTS ICCs for choroidal measurements were 0.92, 0.98, 0.80, and 0.91, respectively, for 3D macula, 3D optic disc, radial, and line scans. ICCs for retinal measurements were 0.39, 0.49, 0.71, and 0.69, respectively. Artifacts were present in up to 9% scans. Signal loss because of blinking was the most common artifact on 3D scans (optic disc scan, 7%; macula scan, 9%), whereas segmentation failure occurred in 4% of radial and 3% of line scans. When scans with image artifacts were excluded, ICCs for choroidal thickness increased to 0.95, 0.99, 0.87, and 0.93 for 3D macula, 3D optic disc, radial, and line scans, respectively. ICCs for retinal thickness increased to 0.88, 0.83, 0.89, and 0.76, respectively. CONCLUSIONS Improved repeatability of automated choroidal and retinal thickness measurements was found with the SS OCT after correction of scan artifacts. Recognition of scan artifacts is important for correct interpretation of SS OCT measurements. PMID:24531020

An optical scan/statistical package for clinical data management in C-L psychiatry.

PubMed

Hammer, J S; Strain, J J; Lyerly, M

1993-03-01

This paper explores aspects of the need for clinical database management systems that permit ongoing service management, measurement of the quality and appropriateness of care, databased administration of consultation liaison (C-L) services, teaching/educational observations, and research. It describes an OPTICAL SCAN databased management system that permits flexible form generation, desktop publishing, and linking of observations in multiple files. This enhanced MICRO-CARES software system--Medical Application Platform (MAP)--permits direct transfer of the data to ASCII and SAS format for mainframe manipulation of the clinical information. The director of a C-L service may now develop his or her own forms, incorporate structured instruments, or develop "branch chains" of essential data to add to the core data set without the effort and expense to reprint forms or consult with commercial vendors.

Adaptive optics for confocal laser scanning microscopy with adjustable pinhole

NASA Astrophysics Data System (ADS)

Yoo, Han Woong; van Royen, Martin E.; van Cappellen, Wiggert A.; Houtsmuller, Adriaan B.; Verhaegen, Michel; Schitter, Georg

2016-04-01

The pinhole plays an important role in confocal laser scanning microscopy (CLSM) for adaptive optics (AO) as well as in imaging, where the size of the pinhole denotes a trade-off between out-of-focus rejection and wavefront distortion. This contribution proposes an AO system for a commercial CLSM with an adjustable square pinhole to cope with such a trade-off. The proposed adjustable pinhole enables to calibrate the AO system and to evaluate the imaging performance. Experimental results with fluorescence beads on the coverslip and at a depth of 40 μm in the human hepatocellular carcinoma cell spheroid demonstrate that the proposed AO system can improve the image quality by the proposed calibration method. The proposed pinhole intensity ratio also indicates the image improvement by the AO correction in intensity as well as resolution.

Handheld optical-resolution photoacoustic microscopy

NASA Astrophysics Data System (ADS)

Lin, Li; Zhang, Pengfei; Xu, Song; Shi, Junhui; Li, Lei; Yao, Junjie; Wang, Lidai; Zou, Jun; Wang, Lihong V.

2017-04-01

Optical-resolution photoacoustic microscopy (OR-PAM) offers label-free in vivo imaging with high spatial resolution by acoustically detecting optical absorption contrasts via the photoacoustic effect. We developed a compact handheld OR-PAM probe for fast photoacoustic imaging. Different from benchtop microscopes, the handheld probe provides flexibility in imaging various anatomical sites. Resembling a cup in size, the probe uses a two-axis water-immersible microelectromechanical system mirror to scan both the illuminating optical beam and resultant acoustic beam. The system performance was tested in vivo by imaging the capillary bed in a mouse ear and both the capillary bed and a mole on a human volunteer.

10-channel fiber array fabrication technique for parallel optical coherence tomography system

NASA Astrophysics Data System (ADS)

Arauz, Lina J.; Luo, Yuan; Castillo, Jose E.; Kostuk, Raymond K.; Barton, Jennifer

2007-02-01

Optical Coherence Tomography (OCT) shows great promise for low intrusive biomedical imaging applications. A parallel OCT system is a novel technique that replaces mechanical transverse scanning with electronic scanning. This will reduce the time required to acquire image data. In this system an array of small diameter fibers is required to obtain an image in the transverse direction. Each fiber in the array is configured in an interferometer and is used to image one pixel in the transverse direction. In this paper we describe a technique to package 15μm diameter fibers on a siliconsilica substrate to be used in a 2mm endoscopic probe tip. Single mode fibers are etched to reduce the cladding diameter from 125μm to 15μm. Etched fibers are placed into a 4mm by 150μm trench in a silicon-silica substrate and secured with UV glue. Active alignment was used to simplify the lay out of the fibers and minimize unwanted horizontal displacement of the fibers. A 10-channel fiber array was built, tested and later incorporated into a parallel optical coherence system. This paper describes the packaging, testing, and operation of the array in a parallel OCT system.

3D dosimetry by optical-CT scanning

NASA Astrophysics Data System (ADS)

Oldham, Mark

2006-12-01

The need for an accurate, practical, low-cost 3D dosimetry system is becoming ever more critical as modern dose delivery techniques increase in complexity and sophistication. A recent report from the Radiological Physics Center (RPC) (1), revealed that 38% of institutions failed the head-and-neck IMRT phantom credentialing test at the first attempt. This was despite generous passing criteria (within 7% dose-difference or 4mm distance-to-agreement) evaluated at a half-dozen points and a single axial plane. The question that arises from this disturbing finding is - what percentage of institutions would have failed if a comprehensive 3D measurement had been feasible, rather than measurements restricted to the central film-plane and TLD points? This question can only be adequately answered by a comprehensive 3D-dosimetry system, which presents a compelling argument for its development as a clinically viable low cost dosimetry solution. Optical-CT dosimetry is perhaps the closest system to providing such a comprehensive solution. In this article, we review the origins and recent developments of optical-CT dosimetry systems. The principle focus is on first generation systems known to have highest accuracy but longer scan times.

ultra-Stable Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (5STAR)

NASA Astrophysics Data System (ADS)

Dunagan, S. E.; Johnson, R. R.; Redemann, J.; Holben, B. N.; Schmid, B.; Flynn, C. J.; Fahey, L.; LeBlanc, S. E.; Liss, J.; Kacenelenbogen, M. S.; Segal-Rosenhaimer, M.; Shinozuka, Y.; Dahlgren, R. P.; Pistone, K.; Karol, Y.

2017-12-01

The Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) combines airborne sun tracking and sky scanning with diffraction spectroscopy to improve knowledge of atmospheric constituents and their links to air pollution and climate. Direct beam hyperspectral measurement of optical depth improves retrievals of gas constituents and determination of aerosol properties. Sky scanning enhances retrievals of aerosol type and size distribution. Hyperspectral cloud-transmitted radiance measurements enable the retrieval of cloud properties from below clouds. These measurements tighten the closure between satellite and ground-based measurements. 4STAR incorporates a modular sun-tracking/ sky-scanning optical head with optical fiber signal transmission to rack mounted spectrometers, permitting miniaturization of the external optical tracking head, and future detector evolution. 4STAR has supported a broad range of flight experiments since it was first flown in 2010. This experience provides the basis for a series of improvements directed toward reducing measurement uncertainty and calibration complexity, and expanding future measurement capabilities, to be incorporated into a new 5STAR instrument. A 9-channel photodiode radiometer with AERONET-matched bandpass filters will be incorporated to improve calibration stability. A wide dynamic range tracking camera will provide a high precision solar position tracking signal as well as an image of sky conditions around the solar axis. An ultrasonic window cleaning system design will be tested. A UV spectrometer tailored for formaldehyde and SO2 gas retrievals will be added to the spectrometer enclosure. Finally, expansion capability for a 4 channel polarized radiometer to measure the Stokes polarization vector of sky light will be incorporated. This paper presents initial progress on this next-generation 5STAR instrument. Keywords: atmosphere; climate; pollution; radiometry; technology; hyperspectral; fiber optic, polarimetry

Bessel beam fluorescence lifetime tomography of live embryos (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xu, Dongli; Peng, Leilei

2016-03-01

Optical tomography allows isotropic 3D imaging of embryos. Scanning-laser optical tomography (SLOT) has superior light collecting efficiency than wide-field optical tomography, making it ideal for fluorescence imaging of live embryos. We previously reported an imaging system that combines SLOT with a novel Fourier-multiplexed fluorescence lifetime imaging (FmFLIM) technique named FmFLIM-SLOT. FmFLIM-SLOT performs multiplexed FLIM-FRET readout of multiple FRET sensors in live embryos. Here we report a recent effort on improving the spatial resolution of the FmFLIM-SLOT system in order to image complex biochemical processes in live embryos at the cellular level. Optical tomography has to compromise between resolution and the depth of view. In SLOT, the commonly-used focused Gaussian beam diverges quickly from the focal plane, making it impossible to achieve high resolution imaging in a large volume specimen. We thus introduce Bessel beam laser-scanning tomography, which illuminates the sample with a spatial-light-modulator-generated Bessel beam that has an extended focal depth. The Bessel beam is scanned across the whole specimen. Fluorescence projection images are acquired at equal angular intervals as the sample rotates. Reconstruction artifacts due to annular-rings of the Bessel beam are removed by a modified 3D filtered back projection algorithm. Furthermore, in combination of Fourier-multiplexing fluorescence lifetime imaging (FmFLIM) method, the Bessel FmFLIM-SLOT system is capable of perform 3D lifetime imaging of live embryos at cellular resolution. The system is applied to in-vivo imaging of transgenic Zebrafish embryos. Results prove that Bessel FmFLIM-SLOT is a promising imaging method in development biology research.

A novel optical rotary encoder with eccentricity self-detection ability.

PubMed

Li, Xuan; Ye, Guoyong; Liu, Hongzhong; Ban, Yaowen; Shi, Yongsheng; Yin, Lei; Lu, Bingheng

2017-11-01

Eccentricity error is the main error source of optical rotary encoders. Real-time detection and compensation of the eccentricity error is an effective way of improving the accuracy of rotary optical encoders. In this paper, a novel rotary optical encoder is presented to realize eccentricity self-detection. The proposed encoder adopts a spider-web-patterned scale grating as a measuring standard which is scanned by a dual-head scanning unit. Two scanning heads of the dual-head scanning unit, which are arranged orthogonally, have the function of scanning the periodic pattern of the scale grating along the angular and radial directions, respectively. By this means, synchronous measurement of angular and radial displacements of the scale grating is realized. This paper gives the details of the operating principle of the rotary optical encoder, developing and testing work of a prototype. The eccentricity self-detection result agrees well with the result measured by an optical microscope. The experimental result preliminarily proves the feasibility and effectiveness of the proposed optical encoder.

A novel optical rotary encoder with eccentricity self-detection ability

NASA Astrophysics Data System (ADS)

Li, Xuan; Ye, Guoyong; Liu, Hongzhong; Ban, Yaowen; Shi, Yongsheng; Yin, Lei; Lu, Bingheng

2017-11-01

Eccentricity error is the main error source of optical rotary encoders. Real-time detection and compensation of the eccentricity error is an effective way of improving the accuracy of rotary optical encoders. In this paper, a novel rotary optical encoder is presented to realize eccentricity self-detection. The proposed encoder adopts a spider-web-patterned scale grating as a measuring standard which is scanned by a dual-head scanning unit. Two scanning heads of the dual-head scanning unit, which are arranged orthogonally, have the function of scanning the periodic pattern of the scale grating along the angular and radial directions, respectively. By this means, synchronous measurement of angular and radial displacements of the scale grating is realized. This paper gives the details of the operating principle of the rotary optical encoder, developing and testing work of a prototype. The eccentricity self-detection result agrees well with the result measured by an optical microscope. The experimental result preliminarily proves the feasibility and effectiveness of the proposed optical encoder.

Optical Scanning for Retrospective Conversion of Information.

ERIC Educational Resources Information Center

Hein, Morten

1986-01-01

This discussion of the use of optical scanning and computer formatting for retrospective conversion focuses on a series of applications known as Optical Scanning for Creation of Information Databases (OSCID). Prior research in this area and the usefulness of OSCID for creating low-priced machine-readable data representing older materials are…

Measurements of CO2 Concentration and Wind Profiles with A Scanning 1.6μm DIAL

NASA Astrophysics Data System (ADS)

Abo, M.; Shibata, Y.; Nagasawa, C.; Nagai, T.; Sakai, T.; Tsukamoto, M.

2012-12-01

Horizontal carbon dioxide (CO2) distribution and wind profiles are important information for understanding of the regional sink and source of CO2. The differential absorption lidar (DIAL) and the Doppler lidar with the range resolution is expected to bring several advantages over passive measurements. We have developed a new scanning 1.6μm DIAL and incoherent Doppler lidar system to perform simultaniously measurements of CO2 concentration and wind speed profiles in the atmosphere. The 1.6μm DIAL and Doppler lidar system consists of the Optical Parametric Generator (OPG) transmitter that excited by the LD pumped Nd:YAG laser with high repetition rate (500 Hz). The receiving optics include the near-infrared photomultiplier tube with high quantum efficiency operating at the photon counting mode, a fiber Bragg grating (FBG) filter to detct Doppler shift, and a 25 cm telescope[1][2]. Laser beam is transmitted coaxially and motorized scanning mirror system can scan the laser beam and field of view 0-360deg horizontally and 0-52deg vertically. We report the results of vertical CO2 scanning measurenents and vertical wind profiles. The scanning elevation angles were from 12deg to 24deg with angular step of 4deg and CO2 concentration profiles were obtained up to 1 km altitude with 200 m altitude resolution. We also obtained vertical wind vector profiles by measuring line-of-sight wind profiles at two azimuth angles with a fixed elevation angle 52deg. Vertical wind vector profiles were obtained up to 5 km altitude with 1 km altitude rasolution. This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and Technology Agency. References [1] L. B. Vann, et al., "Narrowband fiber-optic phase-shifted Fabry-Perot Bragg grating filters for atmospheric water vapor lidar measurements", Appl. Opt., 44, pp. 7371-7377 (2005). [2] Y. Shibata, et al., "1.5μm incoherent Doppler lidar using a FBG filter", Proceedings of 25th International Laser Radar Conference (ILRC25), pp. 338-340 (2010)

Stratified Volume Diffractive Optical Elements as Low-Mass Coherent Lidar Scanners

NASA Technical Reports Server (NTRS)

Chambers, Diana M.; Nordin, Gregory P.; Kavaya, Michael J.

1999-01-01

Transmissive scanning elements for coherent laser radar systems are typically optical wedges, or prisms, which deflect the lidar beam at a specified angle and are then rotated about the instrument optical axis to produce a scan pattern. The wedge is placed in the lidar optical system subsequent to a beam-expanding telescope, implying that it has the largest diameter of any element in the system. The combination of the wedge diameter and asymmetric profile result in the element having very large mass and, consequently, relatively large power consumption required for scanning. These two parameters, mass and power consumption, are among the instrument requirements which need to be minimized when designing a lidar for a space-borne platform. Reducing the scanner contributions in these areas will have a significant effect on the overall instrument specifications, Replacing the optical wedge with a diffraction grating on the surface of a thin substrate is a straight forward approach with potential to reduce the mass of the scanning element significantly. For example, the optical wedge that will be used for the SPAce Readiness Coherent Lidar Experiment (SPARCLE) is approximately 25 cm in diameter and is made from silicon with a wedge angle designed for 30 degree deflection of a beam operating at approx. 2 micrometer wavelength. The mass of this element could be reduced by a factor of four by instead using a fused silica substrate, 1 cm thick, with a grating fabricated on one of the surfaces. For a grating to deflect a beam with a 2 micrometer wavelength by 30 degrees, a period of approximately 4 micrometers is required. This is small enough that fabrication of appropriate high efficiency blazed or multi-phase level diffractive optical gratings is prohibitively difficult. Moreover, bulk or stratified volume holographic approaches appear impractical due to materials limitations at 2 micrometers and the need to maintain adequate wavefront quality. In order to avoid the difficulties encountered in these approaches, we have developed a new type of high-efficiency grating which we call a Stratified Volume Diffractive Optical Element (SVDOE). The features of the gratings in this approach can be easily fabricated using standard photolithography and etching techniques and the materials used in the grating can be chosen specifically for a given application, In this paper we will briefly discuss the SVDOE technique and will present an example design of a lidar scanner using this approach. We will also discuss performance predictions for the example design.

High-speed mapping of grown-in defects and their influence in large-area silicon photovoltaic devices

NASA Astrophysics Data System (ADS)

Sopori, Bhushan; Wei, Chen; Yi, Zhang; Madjdpour, Jamal

2000-03-01

A scanning system for mapping defects, and for measuring their influence on the photovoltaic of Si solar cells, is described. The system uses optical scattering patterns to identify the nature of defects. The local density of the defects is statistically determined from the integrated scattered light. The optical system can also measure the reflectance and the light-induced current which is then used to yield maps of the internal photoresponse of the device.

Evaluation of the effect scan pattern has on the trueness and precision of six intraoral digital impression systems.

PubMed

Mennito, Anthony S; Evans, Zachary P; Lauer, Abigail W; Patel, Ravi B; Ludlow, Mark E; Renne, Walter G

2018-03-01

Clinicians have been slow to adopt digital impression technologies due possibly to perceived technique sensitivities involved in data acquisition. This research has two aims: determine whether scan pattern and sequence affects the accuracy of the three-dimensional (3D) model created from this digital impression and to compare the 5 imaging systems with regards to their scanning accuracy for sextant impressions. Six digital intraoral impression systems were used to scan a typodont sextant with optical properties similar to natural teeth. The impressions were taken using five different scan patterns and the resulting digital models were overlayed on a master digital model to determine the accuracy of each scanner performing each scan pattern. Furthermore, regardless of scan pattern, each digital impression system was evaluated for accuracy to the other systems in this same manner. No differences of significance were noted in the accuracy of 3D models created using six distinct scan patterns with one exception involving the CEREC Omnicam. Planmeca Planscan was determined to be the truest scanner while 3Shape Trios was determined to be the most precise for sextant impression making. Scan pattern does not significantly affect the accuracy of the resulting digital model for sextant scanning. Companies who make digital impression systems often recommend a scan pattern specific for their system. However, every clinical scanning scenario is different and may require a different approach. Knowing how important scan pattern is with regards to accuracy would be helpful for guiding a growing number of practitioners who are utilizing this technology. © 2018 Wiley Periodicals, Inc.

MULTIMODAL IMAGING OF ACUTE EXUDATIVE POLYMORPHOUS VITELLIFORM MACULOPATHY WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY AND ADAPTIVE OPTICS SCANNING LASER OPHTHALMOSCOPY.

PubMed

Skondra, Dimitra; Nesper, Peter L; Fawzi, Amani A

2017-05-16

To report a case of acute exudative polymorphous vitelliform maculopathy including the findings of optical coherence tomography angiography and adaptive optics scanning laser ophthalmoscopy. Findings on clinical examination, color fundus photography, spectral-domain optical coherence tomography, infrared reflectance, autofluorescence, optical coherence tomography angiography, and adaptive optics scanning laser ophthalmoscopy. A 54-year-old white man with no significant medical history and history of smoking presented with bilateral multiple serous and vitelliform detachments consistent with acute exudative polymorphous vitelliform maculopathy. Extensive infectious, inflammatory, and malignancy workup was negative. Spectral-domain optical coherence tomography showed thickened, hyperreflective ellipsoid zone, subretinal fluid, and focal as well as diffuse subretinal hyperreflective material corresponding to the vitelliform lesions. Optical coherence tomography angiography showed normal retinal and choroidal vasculature, whereas adaptive optics scanning laser ophthalmoscopy showed circular focal "target" lesions at the level of the photoreceptors in the area of foveal detachment. Multimodal imaging is valuable in evaluating patients with acute exudative polymorphous vitelliform maculopathy.

Evaluation of a completely robotized neurosurgical operating microscope.

PubMed

Kantelhardt, Sven R; Finke, Markus; Schweikard, Achim; Giese, Alf

2013-01-01

Operating microscopes are essential for most neurosurgical procedures. Modern robot-assisted controls offer new possibilities, combining the advantages of conventional and automated systems. We evaluated the prototype of a completely robotized operating microscope with an integrated optical coherence tomography module. A standard operating microscope was fitted with motors and control instruments, with the manual control mode and balance preserved. In the robot mode, the microscope was steered by a remote control that could be fixed to a surgical instrument. External encoders and accelerometers tracked microscope movements. The microscope was additionally fitted with an optical coherence tomography-scanning module. The robotized microscope was tested on model systems. It could be freely positioned, without forcing the surgeon to take the hands from the instruments or avert the eyes from the oculars. Positioning error was about 1 mm, and vibration faded in 1 second. Tracking of microscope movements, combined with an autofocus function, allowed determination of the focus position within the 3-dimensional space. This constituted a second loop of navigation independent from conventional infrared reflector-based techniques. In the robot mode, automated optical coherence tomography scanning of large surface areas was feasible. The prototype of a robotized optical coherence tomography-integrated operating microscope combines the advantages of a conventional manually controlled operating microscope with a remote-controlled positioning aid and a self-navigating microscope system that performs automated positioning tasks such as surface scans. This demonstrates that, in the future, operating microscopes may be used to acquire intraoperative spatial data, volume changes, and structural data of brain or brain tumor tissue.

Multi-view line-scan inspection system using planar mirrors

NASA Astrophysics Data System (ADS)

Holländer, Bransilav; Štolc, Svorad; Huber-Mörk, Reinhold

2013-04-01

We demonstrate the design, setup, and results for a line-scan stereo image acquisition system using a single area- scan sensor, single lens and two planar mirrors attached to the acquisition device. The acquired object is moving relatively to the acquisition device and is observed under three different angles at the same time. Depending on the specific configuration it is possible to observe the object under a straight view (i.e., looking along the optical axis) and two skewed views. The relative motion between an object and the acquisition device automatically fulfills the epipolar constraint in stereo vision. The choice of lines to be extracted from the CMOS sensor depends on various factors such as the number, position and size of the mirrors, the optical and sensor configuration, or other application-specific parameters like desired depth resolution. The acquisition setup presented in this paper is suitable for the inspection of a printed matter, small parts or security features such as optical variable devices and holograms. The image processing pipeline applied to the extracted sensor lines is explained in detail. The effective depth resolution achieved by the presented system, assembled from only off-the-shelf components, is approximately equal to the spatial resolution and can be smoothly controlled by changing positions and angles of the mirrors. Actual performance of the device is demonstrated on a 3D-printed ground-truth object as well as two real-world examples: (i) the EUR-100 banknote - a high-quality printed matter and (ii) the hologram at the EUR-50 banknote { an optical variable device.

Interferometry-based free space communication and information processing

NASA Astrophysics Data System (ADS)

Arain, Muzammil Arshad

This dissertation studies, analyzes, and experimentally demonstrates the innovative use of interference phenomenon in the field of opto-electronic information processing and optical communications. A number of optical systems using interferometric techniques both in the optical and the electronic domains has been demonstrated in the filed of signal transmission and processing, optical metrology, defense, and physical sensors. Specifically it has been shown that the interference of waves in the form of holography can be exploited to realize a novel optical scanner called Code Multiplexed Optical Scanner (C-MOS). The C-MOS features large aperture, wide scan angles, 3-D beam control, no moving parts, and high beam scanning resolution. A C-MOS based free space optical transceiver for bi-directional communication has also been experimentally demonstrated. For high speed, large bandwidth, and high frequency operation, an optically implemented reconfigurable RF transversal filter design is presented that implements wide range of filtering algorithms. A number of techniques using heterodyne interferometry via acousto-optic device for optical path length measurements have been described. Finally, a whole new class of interferometric sensors for optical metrology and sensing applications is presented. A non-traditional interferometric output signal processing scheme has been developed. Applications include, for example, temperature sensors for harsh environments for a wide temperature range from room temperature to 1000°C.

A mercury arc lamp-based multi-color confocal real time imaging system for cellular structure and function.

PubMed

Saito, Kenta; Kobayashi, Kentaro; Tani, Tomomi; Nagai, Takeharu

2008-01-01

Multi-point scanning confocal microscopy using a Nipkow disk enables the acquisition of fluorescent images with high spatial and temporal resolutions. Like other single-point scanning confocal systems that use Galvano meter mirrors, a commercially available Nipkow spinning disk confocal unit, Yokogawa CSU10, requires lasers as the excitation light source. The choice of fluorescent dyes is strongly restricted, however, because only a limited number of laser lines can be introduced into a single confocal system. To overcome this problem, we developed an illumination system in which light from a mercury arc lamp is scrambled to make homogeneous light by passing it through a multi-mode optical fiber. This illumination system provides incoherent light with continuous wavelengths, enabling the observation of a wide range of fluorophores. Using this optical system, we demonstrate both the high-speed imaging (up to 100 Hz) of intracellular Ca(2+) propagation, and the multi-color imaging of Ca(2+) and PKC-gamma dynamics in living cells.

Optical fabrication and testing; Proceedings of the Meeting, Singapore, Oct. 22-27, 1990

NASA Astrophysics Data System (ADS)

Lorenzen, Manfred; Campbell, Duncan R.; Johnson, Craig W.

1991-03-01

Various papers on optical fabrication and testing are presented. Individual topics addressed include: interferometry with laser diodes, new methods for economic production of prisms and lenses, interferometer accuracy and precision, optical testing with wavelength scanning interferometer, digital Talbot interferometer, high-sensitivity interferometric technique for strain measurements, absolute interferometric testing of spherical surfaces, contouring using gratings created on an LCD panel, three-dimensional inspection using laser-based dynamic fringe projection, noncontact optical microtopography, laser scan microscope and infrared laser scan microscope, photon scanning tunneling microscopy. Also discussed are: combination-matching problems in the layout design of minilaser rangefinder, design and testing of a cube-corner array for laser ranging, mode and far-field pattern of diode laser-phased arrays, new glasses for optics and optoelectronics, optical properties of Li-doped ZnO films, application and machining of Zerodur for optical purposes, finish machining of optical components in mass production.

Scanning optical microscope with long working distance objective

DOEpatents

Cloutier, Sylvain G.

2010-10-19

A scanning optical microscope, including: a light source to generate a beam of probe light; collimation optics to substantially collimate the probe beam; a probe-result beamsplitter; a long working-distance, infinity-corrected objective; scanning means to scan a beam spot of the focused probe beam on or within a sample; relay optics; and a detector. The collimation optics are disposed in the probe beam. The probe-result beamsplitter is arranged in the optical paths of the probe beam and the resultant light from the sample. The beamsplitter reflects the probe beam into the objective and transmits resultant light. The long working-distance, infinity-corrected objective is also arranged in the optical paths of the probe beam and the resultant light. It focuses the reflected probe beam onto the sample, and collects and substantially collimates the resultant light. The relay optics are arranged to relay the transmitted resultant light from the beamsplitter to the detector.

Optical fabrication and testing; Proceedings of the Meeting, Singapore, Oct. 22-27, 1990

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

Lorenzen, M.; Campbell, D.R.; Johnson, C.W.

1991-01-01

Various papers on optical fabrication and testing are presented. Individual topics addressed include: interferometry with laser diodes, new methods for economic production of prisms and lenses, interferometer accuracy and precision, optical testing with wavelength scanning interferometer, digital Talbot interferometer, high-sensitivity interferometric technique for strain measurements, absolute interferometric testing of spherical surfaces, contouring using gratings created on an LCD panel, three-dimensional inspection using laser-based dynamic fringe projection, noncontact optical microtopography, laser scan microscope and infrared laser scan microscope, photon scanning tunneling microscopy. Also discussed are: combination-matching problems in the layout design of minilaser rangefinder, design and testing of a cube-corner arraymore » for laser ranging, mode and far-field pattern of diode laser-phased arrays, new glasses for optics and optoelectronics, optical properties of Li-doped ZnO films, application and machining of Zerodur for optical purposes, finish machining of optical components in mass production.« less

Laser Scanning In Inspection

NASA Astrophysics Data System (ADS)

West, Patricia; Baker, Lionel R.

1989-03-01

This paper is a review of the applications of laser scanning in inspection. The reasons for the choice of a laser in flying spot scanning and the optical properties of a laser beam which are of value in a scanning instrument will be given. The many methods of scanning laser beams in both one and two dimensions will be described. The use of one dimensional laser scanners for automatic surface inspection for transmitting and reflective products will be covered in detail, with particular emphasis on light collection techniques. On-line inspection applications which will be mentioned include: photographic film web, metal strip products, paper web, glass sheet, car body paint surfaces and internal cylinder bores. Two dimensional laser scanning is employed in applications where increased resolution, increased depth of focus, and better contrast are required compared with conventional vidicon TV or solid state array cameras. Such examples as special microscope laser scanning systems and a TV compatible system for use in restricted areas of a nuclear reactor will be described. The technical and economic benefits and limitations of laser scanning video systems will be compared with conventional TV and CCD array devices.

Ultrahigh sensitive optical microangiography for in vivo imaging of microcirculations within human skin tissue beds

PubMed Central

An, Lin; Qin, Jia; Wang, Ruikang K

2010-01-01

In this paper, we demonstrate for the first time that the detailed cutaneous blood flow at capillary level within dermis of human skin can be imaged by optical micro-angiography (OMAG) technique. A novel scanning protocol, i.e. fast B scan mode is used to achieve the capillary flow imaging. We employ a 1310nm system to scan the skin tissue at an imaging rate of 300 frames per second, which requires only ∼5 sec to complete one 3D imaging of capillary blood flow within skin. The technique is sensitive enough to image the very slow blood flows at ∼4 μm/sec. The promising results show a great potential of OMAG's role in the diagnosis, treatment and management of human skin diseases. PMID:20588668

A general high-speed laser drilling method for nonmetal thin material

NASA Astrophysics Data System (ADS)

Cai, Zhijian; Xu, Guangsheng; Xu, Zhou; Xu, Zhiqiang

2013-05-01

Many nonmetal film products, such as herbal plaster, medical adhesive tape and farm plastic film, require drilling dense small holes to enhance the permeability without affecting the appearance. For many medium and small enterprises, a low-cost, high-speed laser drilling machine with the ability of processing different kinds of nonmetal material is highly demanded. In this paper, we proposed a general purpose high-speed laser drilling method for micro-hole production on thin nonmetal film. The system utilizes a rotating polygonal mirror to perform high-speed laser scan, which is simpler and more efficient than the oscillating mirror scan. In this system, an array of closepacked paraboloid mirrors is mounted on the laser scan track to focus the high-power laser onto the material sheet, which could produce up to twenty holes in a single scan. The design of laser scan and focusing optics is optimized to obtain the best holes' quality, and the mirrors can be flexibly adjusted to get different drilling parameters. The use of rotating polygonal mirror scan and close-packed mirror array focusing greatly improves the drilling productivity to enable the machine producing thirty thousand holes per minute. With proper design, the hold uniformity can also get improved. In this paper, the detailed optical and mechanical design is illustrated, the high-speed laser drilling principle is introduced and the preliminary experimental results are presented.

Development of an add-on kit for scanning confocal microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Guo, Kaikai; Zheng, Guoan

2017-03-01

Scanning confocal microscopy is a standard choice for many fluorescence imaging applications in basic biomedical research. It is able to produce optically sectioned images and provide acquisition versatility to address many samples and application demands. However, scanning a focused point across the specimen limits the speed of image acquisition. As a result, scanning confocal microscope only works well with stationary samples. Researchers have performed parallel confocal scanning using digital-micromirror-device (DMD), which was used to project a scanning multi-point pattern across the sample. The DMD based parallel confocal systems increase the imaging speed while maintaining the optical sectioning ability. In this paper, we report the development of an add-on kit for high-speed and low-cost confocal microscopy. By adapting this add-on kit to an existing regular microscope, one can convert it into a confocal microscope without significant hardware modifications. Compared with current DMD-based implementations, the reported approach is able to recover multiple layers along the z axis simultaneously. It may find applications in wafer inspection and 3D metrology of semiconductor circuit. The dissemination of the proposed add-on kit under $1000 budget could also lead to new types of experimental designs for biological research labs, e.g., cytology analysis in cell culture experiments, genetic studies on multicellular organisms, pharmaceutical drug profiling, RNA interference studies, investigation of microbial communities in environmental systems, and etc.

Frequency multiplexed long range swept source optical coherence tomography

PubMed Central

Zurauskas, Mantas; Bradu, Adrian; Podoleanu, Adrian Gh.

2013-01-01

We present a novel swept source optical coherence tomography configuration, equipped with acousto-optic deflectors that can be used to simultaneously acquire multiple B-scans originating from different depths. The sensitivity range of the configuration is evaluated while acquiring five simultaneous B-scans. Then the configuration is employed to demonstrate long range B-scan imaging by combining two simultaneous B-scans from a mouse head sample. PMID:23760762

Effect of reduction time on third order optical nonlinearity of reduced graphene oxide

NASA Astrophysics Data System (ADS)

Sreeja, V. G.; Vinitha, G.; Reshmi, R.; Anila, E. I.; Jayaraj, M. K.

2017-04-01

We report the influence of reduction time on structural, linear and nonlinear optical properties of reduced graphene oxide (rGO) thin films synthesized by spin coating method. We observed that the structural, linear and nonlinear optical properties can be tuned with reduction time in GO is due to the increased structural ordering because of the restoration of sp2 carbon atoms with the time of reduction. The nonlinear absorption studies by open aperture Z-scan technique exhibited a saturable absorption. The nonlinear refraction studies showed the self de focusing nature of rGO by closed aperture Z scan technique. The nonlinear absorption coefficient and saturation intensity varies with the time for reduction of GO which is attributed to the depletion of valence band and the conduction band filling effect. Our results emphasize duration for reduction of GO dependent optical nonlinearity of rGO thin films to a great extent and explore its applications Q switched mode locking laser systems for generating ultra short laser pulses and in optical sensors. The rGO coated films were characterized by X-Ray diffraction method (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis absorption spectroscopy (UV-Vis), Photoluminescence (PL) and Scanning electron microscope (SEM) measurements.

Superresolution upgrade for confocal spinning disk systems using image scanning microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Isbaner, Sebastian; Hähnel, Dirk; Gregor, Ingo; Enderlein, Jörg

2017-02-01

Confocal Spinning Disk Systems are widely used for 3D cell imaging because they offer the advantage of optical sectioning at high framerates and are easy to use. However, as in confocal microscopy, the imaging resolution is diffraction limited, which can be theoretically improved by a factor of 2 using the principle of Image Scanning Microscopy (ISM) [1]. ISM with a Confocal Spinning Disk setup (CSDISM) has been shown to improve contrast as well as lateral resolution (FWHM) from 201 +/- 20 nm to 130 +/- 10 nm at 488 nm excitation. A minimum total acquisition time of one second per ISM image makes this method highly suitable for 3D live cell imaging [2]. Here, we present a multicolor implementation of CSDISM for the popular Micro-Manager Open Source Microscopy platform. Since changes in the optical path are not necessary, this will allow any researcher to easily upgrade their standard Confocal Spinning Disk system at remarkable low cost ( 5000 USD) with an ISM superresolution option. [1]. Müller, C.B. and Enderlein, J. Image Scanning Microscopy. Physical Review Letters 104, (2010). [2]. Schulz, O. et al. Resolution doubling in fluorescence microscopy with confocal spinning-disk image scanning microscopy. Proceedings of the National Academy of Sciences of the United States of America 110, 21000-5 (2013).

SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Optoelectronic processors with scanning CCD photodetectors

NASA Astrophysics Data System (ADS)

Esepkina, N. A.; Lavrov, A. P.; Anan'ev, M. N.; Blagodarnyi, V. S.; Ivanov, S. I.; Mansyrev, M. I.; Molodyakov, S. A.

1995-10-01

Two new types of optoelectronic radio-signal processors were investigated. Charge-coupled device (CCD) photodetectors are used in these processors under continuous scanning conditions, i.e. in a time delay and storage mode. One of these processors is based on a CCD photodetector array with a reference-signal amplitude transparency and the other is an adaptive acousto-optical signal processor with linear frequency modulation. The processor with the transparency performs multichannel discrete—analogue convolution of an input signal with a corresponding kernel of the transformation determined by the transparency. If a light source is an array of light-emitting diodes of special (stripe) geometry, the optical stages of the processor can be made from optical fibre components and the whole processor then becomes a rigid 'sandwich' (a compact hybrid optoelectronic microcircuit). A report is given also of a study of a prototype processor with optical fibre components for the reception of signals from a system with antenna aperture synthesis, which forms a radio image of the Earth.

Optical design of a color film recorder with PLZT modulators

NASA Astrophysics Data System (ADS)

Carson, John F.

1990-08-01

A continuous tone colour film recorder was constructed that exposes 8 x 10 inch ISO 100 daylight-balanced sheet film in ten minutes at a resolution of 1000 pixels/inch. A rotating drum is used for line scan and a leadscrew driven by a stepper motor for page scan. Film loading and unloading is automatic. Light from a stationary xenon arc lamp is split into red green and blue channel components and conducted to a translating optical system by multimode optical fiber cables. Each colour component is then modulated by a small-area PLZT light valve. An annular portion of the modulated light beam is reflected to a photodetector whose signal is used for closed-loop modulator control. The central transmitted portion of the modulated beam is combined with the other colour components into a single beam. This beam illuminates an aperture that is imaged onto the film. An overview of the mechanical electrical and optical concepts will be presented with emphasis on the optical design. 1.

Adaptive optics optical coherence tomography at 120,000 depth scans/s for non-invasive cellular phenotyping of the living human retina

PubMed Central

Torti, Cristiano; Považay, Boris; Hofer, Bernd; Unterhuber, Angelika; Carroll, Joseph; Ahnelt, Peter Kurt; Drexler, Wolfgang

2012-01-01

This paper presents a successful combination of ultra-high speed (120,000 depth scans/s), ultra-high resolution optical coherence tomography with adaptive optics and an achromatizing lens for compensation of monochromatic and longitudinal chromatic ocular aberrations, respectively, allowing for non-invasive volumetric imaging in normal and pathologic human retinas at cellular resolution. The capability of this imaging system is demonstrated here through preliminary studies by probing cellular intraretinal structures that have not been accessible so far with in vivo, non-invasive, label-free imaging techniques, including pigment epithelial cells, micro-vasculature of the choriocapillaris, single nerve fibre bundles and collagenous plates of the lamina cribrosa in the optic nerve head. In addition, the volumetric extent of cone loss in two colour-blinds could be quantified for the first time. This novel technique provides opportunities to enhance the understanding of retinal pathogenesis and early diagnosis of retinal diseases. PMID:19997159

Design considerations for a servo optical projection system

NASA Astrophysics Data System (ADS)

Nadalsky, Michael; Allen, Daniel; Bien, Joseph

1987-01-01

The present servooptical projection system (SOPS) furnishes 'out-the-window' scenery for a pilot-training flight simulator; attention is given to the parametric tradeoffs made in the SOPS' optical design, as well as to its mechanical packaging and the servonetwork performance of the unit as integrated into a research/training helicopter flight simulator. The final SOPS configuration is a function of scan head design, assembly modularity, image deterioration method, and focal lengths and relative apertures.

High resolution multiplexed functional imaging in live embryos (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xu, Dongli; Zhou, Weibin; Peng, Leilei

2017-02-01

Fourier multiplexed fluorescence lifetime imaging (FmFLIM) scanning laser optical tomography (FmFLIM-SLOT) combines FmFLIM and Scanning laser optical tomography (SLOT) to perform multiplexed 3D FLIM imaging of live embryos. The system had demonstrate multiplexed functional imaging of zebrafish embryos genetically express Foster Resonant Energy Transfer (FRET) sensors. However, previous system has a 20 micron resolution because the focused Gaussian beam diverges quickly from the focused plane, makes it difficult to achieve high resolution imaging over a long projection depth. Here, we present a high-resolution FmFLIM-SLOT system with achromatic Bessel beam, which achieves 3 micron resolution in 3D deep tissue imaging. In Bessel-FmFLIM-SLOT, multiple laser excitation lines are firstly intensity modulated by a Michelson interferometer with a spinning polygon mirror optical delay line, which enables Fourier multiplexed multi-channel lifetime measurements. Then, a spatial light modulator and a prism are used to transform the modulated Gaussian laser beam to an achromatic Bessel beam. The achromatic Bessel beam scans across the whole specimen with equal angular intervals as sample rotated. After tomography reconstruction and the frequency domain lifetime analysis method, both the 3D intensity and lifetime image of multiple excitation-emission can be obtained. Using Bessel-FmFLIM-SLOT system, we performed cellular-resolution FLIM tomography imaging of live zebrafish embryo. Genetically expressed FRET sensors in these embryo will allow non-invasive observation of multiple biochemical processes in vivo.

Multimodal ophthalmic imaging using handheld spectrally encoded coherence tomography and reflectometry (SECTR)

NASA Astrophysics Data System (ADS)

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

2018-02-01

Scanning laser ophthalmoscopy (SLO) provides high-speed, noninvasive en face imaging of the retinal fundus. Optical coherence tomography (OCT) is the current "gold-standard" for ophthalmic diagnostic imaging and enables depth-resolved visualization of ophthalmic structures and image-based surrogate biomarkers of disease. We present a compact optical and mechanical design for handheld spectrally encoded coherence tomography and reflectometry (SECTR) for multimodality en face spectrally encoded reflectometry (SER) and cross-sectional OCT imaging. We custom-designed a double-pass telecentric scan lens, which halves the size of 4-f optical relays and allowed us to reduce the footprint of our SECTR scan-head by a factor of >2.7x (volume) over our previous design. The double-pass scan lens was optimized for diffraction-limited performance over a +/-10° scan field. SECTR optics and optomechanics were combined in a compact rapid-prototyped enclosure with dimensions 87 x 141.8 x 137 mm (w x h x d). SECTR was implemented using a custom-built 400 kHz 1050 nm swept-source. OCT and SER were simultaneously digitized on dual input channels of a 4 GS/s digitizer at 1.4 GS/s per channel. In vivo human en face SER and cross-sectional OCT images were acquired at 350 fps. OCT volumes of 1000 B-scans were acquired in 2.86 s. We believe clinical translation of our compact handheld design will benefit point-of-care ophthalmic diagnostics in patients who are unable to be imaged on conventional slit-lamp based systems, such as infants and the bedridden. When combined with multi-volumetric registration methods, handheld SECTR will have advantages in motion-artifact free imaging over existing handheld technologies.

Nanopositioning for polarimetric characterization.

PubMed

Qureshi, Naser; Kolokoltsev, Oleg V; Ortega-Martínez, Roberto; Ordoñez-Romero, C L

2008-12-01

A positioning system with approximately nanometer resolution has been developed based on a new implementation of a motor-driven screw scheme. In contrast to conventional positioning systems based on piezoelectric elements, this system shows remarkably low levels of drift and vibration, and eliminates the need for position feedback during typical data acquisition processes. During positioning or scanning processes, non-repeatability and hysteresis problems inherent in mechanical positioning systems are greatly reduced using a software feedback scheme. As a result, we are able to demonstrate an average mechanical resolution of 1.45 nm and near diffraction-limited imaging using scanning optical microscopy. We propose this approach to nanopositioning as a readily accessible alternative enabling high spatial resolution scanning probe characterization (e.g., polarimetry) and provide practical details for its implementation.

Ophthalmological OCT measuring arm design

NASA Astrophysics Data System (ADS)

Xu, Xiaonan; Gao, Jiansong; Guo, Jihua; Xue, Ping

2002-06-01

This paper presents a novel ophthamological optical coherence tomography detecting instrument that we design and introduces measuring arm emphatically. For the glaucoma is very common in the orient, this system can achieve both the eyeground detection and the canthus detection. And it combines the cranny lamp's conventional detection with optical coherence tomography. In order to gain the best resolution and the largest scanning range in the OCT detection, we find the optical system should obey these principles in the measuring arm design: (i) the parallel light from the collimator goes through the lens and focuses on the slot of the cranny lamp. The movement of the scanning point produced by the scanner is carrying on along the slot. (Ii) In the whole light route, the scanner images on the laser object lens of the OCT. The center light of the infrared goes through the center of the object lens all the time. Considering all the system, this design has a longitudinal resolution of 15micrometers , and a transverse resolution of 20micrometers at imaging velocity of 4 frames per second.

Design validation of an eye-safe scanning aerosol lidar with the Center for Lidar and Atmospheric Sciences Students (CLASS) at Hampton University

NASA Astrophysics Data System (ADS)

Richter, Dale A.; Higdon, N. S.; Ponsardin, Patrick L.; Sanchez, David; Chyba, Thomas H.; Temple, Doyle A.; Gong, Wei; Battle, Russell; Edmondson, Mika; Futrell, Anne; Harper, David; Haughton, Lincoln; Johnson, Demetra; Lewis, Kyle; Payne-Baggott, Renee S.

2002-01-01

ITTs Advanced Engineering and Sciences Division and the Hampton University Center for Lidar and Atmospheric Sciences Students (CLASS) team have worked closely to design, fabricate and test an eye-safe, scanning aerosol-lidar system that can be safely deployed and used by students form a variety of disciplines. CLASS is a 5-year undergraduate- research training program funded by NASA to provide hands-on atmospheric-science and lidar-technology education. The system is based on a 1.5 micron, 125 mJ, 20 Hz eye-safe optical parametric oscillator (OPO) and will be used by the HU researchers and students to evaluate the biological impact of aerosols, clouds, and pollution a variety of systems issues. The system design tasks we addressed include the development of software to calculate eye-safety levels and to model lidar performance, implementation of eye-safety features in the lidar transmitter, optimization of the receiver using optical ray tracing software, evaluation of detectors and amplifiers in the near RI, test of OPO and receiver technology, development of hardware and software for laser and scanner control and video display of the scan region.

Using ultrahigh sensitive optical microangiography to achieve comprehensive depth resolved microvasculature mapping for human retina

NASA Astrophysics Data System (ADS)

An, Lin; Shen, Tueng T.; Wang, Ruikang K.

2011-10-01

This paper presents comprehensive and depth-resolved retinal microvasculature images within human retina achieved by a newly developed ultrahigh sensitive optical microangiography (UHS-OMAG) system. Due to its high flow sensitivity, UHS-OMAG is much more sensitive to tissue motion due to the involuntary movement of the human eye and head compared to the traditional OMAG system. To mitigate these motion artifacts on final imaging results, we propose a new phase compensation algorithm in which the traditional phase-compensation algorithm is repeatedly used to efficiently minimize the motion artifacts. Comparatively, this new algorithm demonstrates at least 8 to 25 times higher motion tolerability, critical for the UHS-OMAG system to achieve retinal microvasculature images with high quality. Furthermore, the new UHS-OMAG system employs a high speed line scan CMOS camera (240 kHz A-line scan rate) to capture 500 A-lines for one B-frame at a 400 Hz frame rate. With this system, we performed a series of in vivo experiments to visualize the retinal microvasculature in humans. Two featured imaging protocols are utilized. The first is of the low lateral resolution (16 μm) and a wide field of view (4 × 3 mm2 with single scan and 7 × 8 mm2 for multiple scans), while the second is of the high lateral resolution (5 μm) and a narrow field of view (1.5 × 1.2 mm2 with single scan). The great imaging performance delivered by our system suggests that UHS-OMAG can be a promising noninvasive alternative to the current clinical retinal microvasculature imaging techniques for the diagnosis of eye diseases with significant vascular involvement, such as diabetic retinopathy and age-related macular degeneration.

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.

An instrumental approach to combining confocal microspectroscopy and 3D scanning probe nanotomography.

PubMed

Mochalov, Konstantin E; Chistyakov, Anton A; Solovyeva, Daria O; Mezin, Alexey V; Oleinikov, Vladimir A; Vaskan, Ivan S; Molinari, Michael; Agapov, Igor I; Nabiev, Igor; Efimov, Anton E

2017-11-01

In the past decade correlative microscopy, which combines the potentials of different types of high-resolution microscopies with a variety of optical microspectroscopy techniques, has been attracting increasing attention in material science and biological research. One of outstanding solutions in this area is the combination of scanning probe microscopy (SPM), which provides data on not only the topography, but also the spatial distribution of a wide range of physical properties (elasticity, conductivity, etc.), with ultramicrotomy, allowing 3D multiparametric examination of materials. The combination of SPM and ultramicrotomy (scanning probe nanotomography) is very appropriate for characterization of soft multicompound nanostructurized materials, such as polymer matrices and microstructures doped with different types of nanoparticles (magnetic nanoparticles, quantum dots, nanotubes, etc.), and biological materials. A serious problem of this technique is a lack of chemical and optical characterization tools, which may be solved by using optical microspectroscopy. Here, we report the development of an instrumental approach to combining confocal microspectroscopy and 3D scanning probe nanotomography in a single apparatus. This approach retains all the advantages of SPM and upright optical microspectroscopy and allows 3D multiparametric characterization using both techniques. As the first test of the system developed, we have performed correlative characterization of the morphology and the magnetic and fluorescent properties of fluorescent magnetic microspheres doped with a fluorescent dye and magnetic nanoparticles. The results of this study can be used to obtain 3D volume images of a specimen for most high-resolution near-field scanning probe microscopies: SNOM, TERS, AFM-IR, etc. This approach will result in development of unique techniques combining the advantages of SPM (nanoscale morphology and a wide range of physical parameters) and high-resolution optical microspectroscopy (nanoscale chemical mapping and optical properties) and allowing simultaneous 3D measurements. Copyright © 2017 Elsevier B.V. All rights reserved.

Laser line scan performance prediction

NASA Astrophysics Data System (ADS)

Mahoney, Kevin L.; Schofield, Oscar; Kerfoot, John; Giddings, Tom; Shirron, Joe; Twardowski, Mike

2007-09-01

The effectiveness of sensors that use optical measurements for the laser detection and identification of subsurface mines is directly related to water clarity. The primary objective of the work presented here was to use the optical data collected by UUV (Slocum Glider) surveys of an operational areas to estimate the performance of an electro-optical identification (EOID) Laser Line Scan (LLS) system during RIMPAC 06, an international naval exercise off the coast of Hawaii. Measurements of optical backscattering and beam attenuation were made with a Wet Labs, Inc. Scattering Absorption Meter (SAM), mounted on a Rutgers University/Webb Research Slocum glider. The optical data universally indicated extremely clear water in the operational area, except very close to shore. The beam-c values from the SAM sensor were integrated to three attenuation lengths to provide an estimate of how well the LLS would perform in detecting and identifying mines in the operational areas. Additionally, the processed in situ optical data served as near-real-time input to the Electro-Optic Detection Simulator, ver. 3 (EODES-3; Metron, Inc.) model for EOID performance prediction. Both methods of predicting LLS performance suggested a high probability of detection and probability of identification. These predictions were validated by the actual performance of the LLS as the EOID system yielded imagery from which reliable mine identification could be made. Future plans include repeating this work in more optically challenging water types to demonstrate the utility of pre-mission UUV surveys of operational areas as a tactical decision aid for planning EOID missions.

Determination of nonlinear optical properties by time resolved Z-scan in Nd-doped phosphate glass

NASA Astrophysics Data System (ADS)

de Souza, J. M.; de Lima, W. J.; Pilla, V.; Andrade, A. A.; Dantas, N. O.; Messias, D. N.

2017-02-01

In this work, we have used a Ti3+:Safira laser tuned at 803nm to performed time-resolved measurements using the Z-scan technique to characterize the nonlinear optical properties of phosphate glasses. The glass matrices, labeled PAN (P2O5-Al2O3-Na2CO3) and PANK (P2O5-Al2O3- Na2O-K2O), were doped with increasing Nd3+ concentration, ranging from 0.5 to 5 wt%. For both systems, we have seen that the optical nonlinearity has a linear dependence with the doping ion concentration. Therefore, we propose a new approach to obtain the parameters Δα and Δσ. All results obtained are in good agreement with others found in the literature.

Micromachined mirrors for raster-scanning displays and optical fiber switches

NASA Astrophysics Data System (ADS)

Hagelin, Paul Merritt

Micromachines and micro-optics have the potential to shrink the size and cost of free-space optical systems, enabling a new generation of high-performance, compact projection displays and telecommunications equipment. In raster-scanning displays and optical fiber switches, a free-space optical beam can interact with multiple tilt- up micromirrors fabricated on a single substrate. The size, rotation angle, and flatness of the mirror surfaces determine the number of pixels in a raster-display or ports in an optical switch. Single-chip and two-chip optical raster display systems demonstrate static mirror curvature correction, an integrated electronic driver board, and dynamic micromirror performance. Correction for curvature caused by a stress gradient in the micromirror leads to resolution of 102 by 119 pixels in the single-chip display. The optical design of the two-chip display features in-situ mirror curvature measurement and adjustable image magnification with a single output lens. An electronic driver board synchronizes modulation of the optical source with micromirror actuation for the display of images. Dynamic off-axis mirror motion is shown to have minimal influence on resolution. The confocal switch, a free-space optical fiber cross- connect, incorporates micromirrors having a design similar to the image-refresh scanner. Two micromirror arrays redirect optical beams from an input fiber array to the output fibers. The switch architecture supports simultaneous switching of multiple wavelength channels. A 2x2 switch configuration, using single-mode optical fiber at 1550 mn, is demonstrated with insertion loss of -4.2 dB and cross-talk of -50.5 dB. The micromirrors have sufficient size and angular range for scaling to a 32x32 cross-connect switch that has low insertion-loss and low cross-talk.

Pencil beam characteristics of the next-generation proton scanning gantry of PSI: design issues and initial commissioning results

NASA Astrophysics Data System (ADS)

Pedroni, E.; Meer, D.; Bula, C.; Safai, S.; Zenklusen, S.

2011-07-01

In this paper we report on the main design features, on the realization process and on selected first results of the initial commissioning of the new Gantry 2 of PSI for the delivery of proton therapy with new advanced pencil beam scanning techniques. We present briefly the characteristics of the new gantry system with main emphasis on the beam optics, on the characterization of the pencil beam used for scanning and on the performance of the scanning system. The idea is to give an overview of the major components of the whole system. The main long-term technical goal of the new equipment of Gantry 2 is to expand the use of pencil beam scanning to the whole spectrum of clinical indications including moving targets. We report here on the initial experience and problems encountered in the development of the system with selected preliminary results of the ongoing commissioning of Gantry 2.

Biotechnology

NASA Image and Video Library

2003-01-22

ProVision Technologies, a NASA research partnership center at Sternis Space Center in Mississippi, has developed a new hyperspectral imaging (HSI) system that is much smaller than the original large units used aboard remote sensing aircraft and satellites. The new apparatus is about the size of a breadbox. HSI may be useful to ophthalmologists to study and diagnose eye health, both on Earth and in space, by examining the back of the eye to determine oxygen and blood flow quickly and without any invasion. ProVision's hyperspectral imaging system can scan the human eye and produce a graph showing optical density or light absorption, which can then be compared to a graph from a normal eye. Scans of the macula, optic disk or optic nerve head, and blood vessels can be used to detect anomalies and identify diseases in this delicate and important organ. ProVision has already developed a relationship with the University of Alabama at Birmingham, but is still on the lookout for a commercial partner in this application.

Biotechnology

NASA Image and Video Library

2003-01-22

ProVision Technologies, a NASA commercial space center at Sternis Space Center in Mississippi, has developed a new hyperspectral imaging (HSI) system that is much smaller than the original large units used aboard remote sensing aircraft and satellites. The new apparatus is about the size of a breadbox. HSI may be useful to ophthalmologists to study and diagnose eye health, both on Earth and in space, by examining the back of the eye to determine oxygen and blood flow quickly and without any invasion. ProVision's hyperspectral imaging system can scan the human eye and produce a graph showing optical density or light absorption, which can then be compared to a graph from a normal eye. Scans of the macula, optic disk or optic nerve head, and blood vessels can be used to detect anomalies and identify diseases in this delicate and important organ. ProVision has already developed a relationship with the University of Alabama at Birmingham, but is still on the lookout for a commercial partner in this application.

A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

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

Wang, Wenbo; Department of Dermatology and Skin Science, University of British Columbia, 835 West 10th Avenue, Vancouver, British Columbia V5Z 4E8; Department of Biomedical Engineering, University of British Columbia, KAIS 5500, 2332 Main Mall, Vancouver, British Columbia V6T 1Z4

Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra.more » Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to −0.70 nm within the spectral range of 500–850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.« less

Computational modeling of optical projection tomographic microscopy using the finite difference time domain method.

PubMed

Coe, Ryan L; Seibel, Eric J

2012-12-01

We present a method for modeling image formation in optical projection tomographic microscopy (OPTM) using high numerical aperture (NA) condensers and objectives. Similar to techniques used in computed tomography, OPTM produces three-dimensional, reconstructed images of single cells from two-dimensional projections. The model is capable of simulating axial scanning of a microscope objective to produce projections, which are reconstructed using filtered backprojection. Simulation of optical scattering in transmission optical microscopy is designed to analyze all aspects of OPTM image formation, such as degree of specimen staining, refractive-index matching, and objective scanning. In this preliminary work, a set of simulations is performed to examine the effect of changing the condenser NA, objective scan range, and complex refractive index on the final reconstruction of a microshell with an outer radius of 1.5 μm and an inner radius of 0.9 μm. The model lays the groundwork for optimizing OPTM imaging parameters and triaging efforts to further improve the overall system design. As the model is expanded in the future, it will be used to simulate a more realistic cell, which could lead to even greater impact.

High capacity aerodynamic air bearing (HCAB) for laser scanning applications

NASA Astrophysics Data System (ADS)

Coleman, Sean M.

2005-08-01

A high capacity aerodynamic air bearing (HCAB) has been developed for the laser scanning market. The need for increasing accuracies in the prepress and print plate-making market is causing a shift from ball bearing to air bearing scanners. Aerostatic air bearings are a good option to meet this demand for better performance however, these bearings tend to be expensive and require an additional air supply, filtering and drying system. Commercially available aerodynamic bearings have been typically limited to small mirrors, on the order of 3.5" diameter and less than 0.5" thick. A large optical facet, hence a larger mirror, is required to generate the high number of pixels needed for this type of application. The larger optic necessitated the development of a high capacity 'self-generating' or aerodynamic air bearing that would meet the needs of the optical scanning market. Its capacity is rated up to 6.0" diameter and 1.0" thick optics. The performance of an aerodynamic air bearing is better than a ball bearing and similar to an aerostatic air bearing. It retains the low costs while eliminating the need for ancillary equipment required by an aerostatic bearing.

Book Reviews

NASA Astrophysics Data System (ADS)

Radl, Bruce M.; Donnelly, J. P.; Oliner, Arthur A.

1986-08-01

Laser Beam Scanning: Opto-mechanical devices, systems, and data Storage Optics-Reviewed by Bruce M. Radl; Integrated Optoelectronics-Reviewed by J.P. Donnelly; Planar Circuits for Microwaves and Lightwaves-Reviewed by Arthur A. Oliner;

Scanning system, infrared noise equivalent temperature difference: Measurement procedure

NASA Technical Reports Server (NTRS)

Cannon, J. B., Jr.

1975-01-01

A procedure is described for determining the noise equivalent difference temperature for infrared electro-optical instruments. The instrumentation required, proper measurements, and methods of calculation are included.

An x-ray fluorescence imaging system for gold nanoparticle detection.

PubMed

Ricketts, K; Guazzoni, C; Castoldi, A; Gibson, A P; Royle, G J

2013-11-07

Gold nanoparticles (GNPs) may be used as a contrast agent to identify tumour location and can be modified to target and image specific tumour biological parameters. There are currently no imaging systems in the literature that have sufficient sensitivity to GNP concentration and distribution measurement at sufficient tissue depth for use in in vivo and in vitro studies. We have demonstrated that high detecting sensitivity of GNPs can be achieved using x-ray fluorescence; furthermore this technique enables greater depth imaging in comparison to optical modalities. Two x-ray fluorescence systems were developed and used to image a range of GNP imaging phantoms. The first system consisted of a 10 mm(2) silicon drift detector coupled to a slightly focusing polycapillary optic which allowed 2D energy resolved imaging in step and scan mode. The system has sensitivity to GNP concentrations as low as 1 ppm. GNP concentrations different by a factor of 5 could be resolved, offering potential to distinguish tumour from non-tumour. The second system was designed to avoid slow step and scan image acquisition; the feasibility of excitation of the whole specimen with a wide beam and detection of the fluorescent x-rays with a pixellated controlled drift energy resolving detector without scanning was investigated. A parallel polycapillary optic coupled to the detector was successfully used to ascertain the position where fluorescence was emitted. The tissue penetration of the technique was demonstrated to be sufficient for near-surface small-animal studies, and for imaging 3D in vitro cellular constructs. Previous work demonstrates strong potential for both imaging systems to form quantitative images of GNP concentration.

Fan-beam scanning laser optical computed tomography for large volume dosimetry

NASA Astrophysics Data System (ADS)

Dekker, K. H.; Battista, J. J.; Jordan, K. J.

2017-05-01

A prototype scanning-laser fan beam optical CT scanner is reported which is capable of high resolution, large volume dosimetry with reasonable scan time. An acylindrical, asymmetric aquarium design is presented which serves to 1) generate parallel-beam scan geometry, 2) focus light towards a small acceptance angle detector, and 3) avoid interference fringe-related artifacts. Preliminary experiments with uniform solution phantoms (11 and 15 cm diameter) and finger phantoms (13.5 mm diameter FEP tubing) demonstrate that the design allows accurate optical CT imaging, with optical CT measurements agreeing within 3% of independent Beer-Lambert law calculations.

A Quantitative Diffuse Reflectance Imaging (QDRI) System for Comprehensive Surveillance of the Morphological Landscape in Breast Tumor Margins.

PubMed

Nichols, Brandon S; Schindler, Christine E; Brown, Jonathon Q; Wilke, Lee G; Mulvey, Christine S; Krieger, Marlee S; Gallagher, Jennifer; Geradts, Joseph; Greenup, Rachel A; Von Windheim, Jesko A; Ramanujam, Nirmala

2015-01-01

In an ongoing effort to address the clear clinical unmet needs surrounding breast conserving surgery (BCS), our group has developed a next-generation multiplexed optical-fiber-based tool to assess breast tumor margin status during initial surgeries. Specifically detailed in this work is the performance and clinical validation of a research-grade intra-operative tool for margin assessment based on diffuse optical spectroscopy. Previous work published by our group has illustrated the proof-of-concept generations of this device; here we incorporate a highly optimized quantitative diffuse reflectance imaging (QDRI) system utilizing a wide-field (imaging area = 17 cm(2)) 49-channel multiplexed fiber optic probe, a custom raster-scanning imaging platform, a custom dual-channel white LED source, and an astronomy grade imaging CCD and spectrograph. The system signal to noise ratio (SNR) was found to be greater than 40 dB for all channels. Optical property estimation error was found to be less than 10%, on average, over a wide range of absorption (μa = 0-8.9 cm(-1)) and scattering (μs' = 7.0-9.7 cm(-1)) coefficients. Very low inter-channel and CCD crosstalk was observed (2% max) when used on turbid media (including breast tissue). A raster-scanning mechanism was developed to achieve sub-pixel resolution and was found to be optimally performed at an upsample factor of 8, affording 0.75 mm spatially resolved diffuse reflectance images (λ = 450-600 nm) of an entire margin (area = 17 cm(2)) in 13.8 minutes (1.23 cm(2)/min). Moreover, controlled pressure application at the probe-tissue interface afforded by the imaging platform reduces repeated scan variability, providing <1% variation across repeated scans of clinical specimens. We demonstrate the clinical utility of this device through a pilot 20-patient study of high-resolution optical parameter maps of the ratio of the β-carotene concentration to the reduced scattering coefficient. An empirical cumulative distribution function (eCDF) analysis is used to reduce optical property maps to quantitative distributions representing the morphological landscape of breast tumor margins. The optimizations presented in this work provide an avenue to rapidly survey large tissue areas on intra-operative time scales with improved sensitivity to regions of focal disease that may otherwise be overlooked.

Application of Replica Technique and SEM in Accuracy Measurement of Ceramic Crowns

NASA Astrophysics Data System (ADS)

Trifkovic, B.; Budak, I.; Todorovic, A.; Hodolic, J.; Puskar, T.; Jevremovic, D.; Vukelic, D.

2012-01-01

The paper presents a comparative study of the measuring values of the marginal gap related to the ceramic crowns made by dental CAD/CAM system using the replica technique and SEM. The study was conducted using three experimental groups, which consisted of ceramic crowns manufactured by the Cerec CAD/CAM system. The scanning procedure was carried out using three specialized dental 3D digitization systems from the Cerec family - two types of extraoral optical scanning systems and an intraoral optical scanner. Measurements of the marginal gap were carried out using the replica technique and SEM. The comparison of aggregate values of the marginal gap using the replica technique showed a statistically significant difference between the systems. The measured values of marginal gaps of ceramic crowns using the replica technique were significantly lower compared to those measured by SEM. The results indicate that the choice of technique for measuring the accuracy of ceramic crowns influences the final results of investigation.

Super-resolution for scanning light stimulation systems

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

Bitzer, L. A.; Neumann, K.; Benson, N., E-mail: niels.benson@uni-due.de

Super-resolution (SR) is a technique used in digital image processing to overcome the resolution limitation of imaging systems. In this process, a single high resolution image is reconstructed from multiple low resolution images. SR is commonly used for CCD and CMOS (Complementary Metal-Oxide-Semiconductor) sensor images, as well as for medical applications, e.g., magnetic resonance imaging. Here, we demonstrate that super-resolution can be applied with scanning light stimulation (LS) systems, which are common to obtain space-resolved electro-optical parameters of a sample. For our purposes, the Projection Onto Convex Sets (POCS) was chosen and modified to suit the needs of LS systems.more » To demonstrate the SR adaption, an Optical Beam Induced Current (OBIC) LS system was used. The POCS algorithm was optimized by means of OBIC short circuit current measurements on a multicrystalline solar cell, resulting in a mean square error reduction of up to 61% and improved image quality.« less

Developments in holographic-based scanner designs

NASA Astrophysics Data System (ADS)

Rowe, David M.

1997-07-01

Holographic-based scanning systems have been used for years in the high resolution prepress markets where monochromatic lasers are generally utilized. However, until recently, due to the dispersive properties of holographic optical elements (HOEs), along with the high cost associated with recording 'master' HOEs, holographic scanners have not been able to penetrate major scanning markets such as the laser printer and digital copier markets, low to mid-range imagesetter markets, and the non-contact inspection scanner market. Each of these markets has developed cost effective laser diode based solutions using conventional scanning approaches such as polygon/f-theta lens combinations. In order to penetrate these markets, holographic-based systems must exhibit low cost and immunity to wavelength shifts associated with laser diodes. This paper describes recent developments in the design of holographic scanners in which multiple HOEs, each possessing optical power, are used in conjunction with one curved mirror to passively correct focal plane position errors and spot size changes caused by the wavelength instability of laser diodes. This paper also describes recent advancements in low cost production of high quality HOEs and curved mirrors. Together these developments allow holographic scanners to be economically competitive alternatives to conventional devices in every segment of the laser scanning industry.

Intraoperative optical coherence tomography of the cerebral cortex using a 7 degree-of freedom robotic arm

NASA Astrophysics Data System (ADS)

Reyes Perez, Robnier; Jivraj, Jamil; Yang, Victor X. D.

2017-02-01

Optical Coherence Tomography (OCT) provides a high-resolution imaging technique with limited depth penetration. The current use of OCT is limited to relatively small areas of tissue for anatomical structure diagnosis or minimally invasive guided surgery. In this study, we propose to image a large area of the surface of the cerebral cortex. This experiment aims to evaluate the potential difficulties encountered when applying OCT imaging to large and irregular surface areas. The current state-of-the-art OCT imaging technology uses scanning systems with at most 3 degrees-of-freedom (DOF) to obtain a 3D image representation of the sample tissue. We propose the use of a 7 DOF industrial robotic arm to increase the scanning capabilities of our OCT. Such system will be capable of acquiring data from large samples of tissue that are too irregular for conventional methods. Advantages and disadvantages of our system are discussed.

Ultra-Stable Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (5STAR)

NASA Technical Reports Server (NTRS)

Dunagan, Stephen E.; Johnson, Roy R.; Redemann, Jens; Holben, Brent N.; Schmidt, Beat; Flynn, Connor Joseph; Fahey, Lauren; LeBlanc, Samuel; Liss, Jordan; Kacenelenbogen, Meloe S.;

Predicting scattering scanning near-field optical microscopy of mass-produced plasmonic devices

NASA Astrophysics Data System (ADS)

Otto, Lauren M.; Burgos, Stanley P.; Staffaroni, Matteo; Ren, Shen; Süzer, Özgün; Stipe, Barry C.; Ashby, Paul D.; Hammack, Aeron T.

2018-05-01

Scattering scanning near-field optical microscopy enables optical imaging and characterization of plasmonic devices with nanometer-scale resolution well below the diffraction limit. This technique enables developers to probe and understand the waveguide-coupled plasmonic antenna in as-fabricated heat-assisted magnetic recording heads. In order to validate and predict results and to extract information from experimental measurements that is physically comparable to simulations, a model was developed to translate the simulated electric field into expected near-field measurements using physical parameters specific to scattering scanning near-field optical microscopy physics. The methods used in this paper prove that scattering scanning near-field optical microscopy can be used to determine critical sub-diffraction-limited dimensions of optical field confinement, which is a crucial metrology requirement for the future of nano-optics, semiconductor photonic devices, and biological sensing where the near-field character of light is fundamental to device operation.

Effect of improper scan alignment on retinal nerve fiber layer thickness measurements using Stratus optical coherence tomograph.

PubMed

Vizzeri, Gianmarco; Bowd, Christopher; Medeiros, Felipe A; Weinreb, Robert N; Zangwill, Linda M

2008-08-01

Misalignment of the Stratus optical coherence tomograph scan circle placed by the operator around the optic nerve head (ONH) during each retinal nerve fiber layer (RNFL) examination can affect the instrument reproducibility and its theoretical ability to detect true structural changes in the RNFL thickness over time. We evaluated the effect of scan circle placement on RNFL measurements. Observational clinical study. Sixteen eyes of 8 normal participants were examined using the Stratus optical coherence tomograph Fast RNFL thickness acquisition protocol (software version 4.0.7; Carl Zeiss Meditec, Dublin, CA). Four consecutive images were taken by the same operator with the circular scan centered on the optic nerve head. Four images each with the scan displaced superiorly, inferiorly, temporally, and nasally were also acquired. Differences in average and sectoral RNFL thicknesses were determined. For the centered scans, the coefficients of variation (CV) and the intraclass correlation coefficient for the average RNFL thickness measured were calculated. When the average RNFL thickness of the centered scans was compared with the average RNFL thickness of the displaced scans individually using analysis of variance with post-hoc analysis, no difference was found between the average RNFL thickness of the nasally (105.2 microm), superiorly (106.2 microm), or inferiorly (104.1 microm) displaced scans and the centered scans (106.4 microm). However, a significant difference (analysis of variance with Dunnett's test: F=8.82, P<0.0001) was found between temporally displaced scans (115.8 microm) and centered scans. Significant differences in sectoral RNFL thickness measurements were found between centered and each displaced scan. The coefficient of variation for average RNFL thickness was 1.75% and intraclass correlation coefficient was 0.95. In normal eyes, average RNFL thickness measurements are robust and similar with significant superior, inferior, and nasal scan displacement, but average RNFL thickness is greater when scans are displaced temporally. Parapapillary scan misalignment produces significant changes in RNFL assessment characterized by an increase in measured RNFL thickness in the quadrant in which the scan is closer to the disc, and a significant decrease in RNFL thickness in the quadrant in which the scan is displaced further from the optic disc.

Scalable wide-field optical coherence tomography-based angiography for in vivo imaging applications

PubMed Central

Xu, Jingjiang; Wei, Wei; Song, Shaozhen; Qi, Xiaoli; Wang, Ruikang K.

2016-01-01

Recent advances in optical coherence tomography (OCT)-based angiography have demonstrated a variety of biomedical applications in the diagnosis and therapeutic monitoring of diseases with vascular involvement. While promising, its imaging field of view (FOV) is however still limited (typically less than 9 mm2), which somehow slows down its clinical acceptance. In this paper, we report a high-speed spectral-domain OCT operating at 1310 nm to enable wide FOV up to 750 mm2. Using optical microangiography (OMAG) algorithm, we are able to map vascular networks within living biological tissues. Thanks to 2,048 pixel-array line scan InGaAs camera operating at 147 kHz scan rate, the system delivers a ranging depth of ~7.5 mm and provides wide-field OCT-based angiography at a single data acquisition. We implement two imaging modes (i.e., wide-field mode and high-resolution mode) in the OCT system, which gives highly scalable FOV with flexible lateral resolution. We demonstrate scalable wide-field vascular imaging for multiple finger nail beds in human and whole brain in mice with skull left intact at a single 3D scan, promising new opportunities for wide-field OCT-based angiography for many clinical applications. PMID:27231630

Converting optical scanning holograms of real objects to binary Fourier holograms using an iterative direct binary search algorithm.

PubMed

Leportier, Thibault; Park, Min Chul; Kim, You Seok; Kim, Taegeun

2015-02-09

In this paper, we present a three-dimensional holographic imaging system. The proposed approach records a complex hologram of a real object using optical scanning holography, converts the complex form to binary data, and then reconstructs the recorded hologram using a spatial light modulator (SLM). The conversion from the recorded hologram to a binary hologram is achieved using a direct binary search algorithm. We present experimental results that verify the efficacy of our approach. To the best of our knowledge, this is the first time that a hologram of a real object has been reconstructed using a binary SLM.

Fiber optic light collection system for scanning-tunneling-microscope-induced light emission.

PubMed

Watkins, Neil J; Long, James P; Kafafi, Zakya H; Mäkinen, Antti J

2007-05-01

We report a compact light collection scheme suitable for retrofitting a scanning tunneling microscope (STM) for STM-induced light emission experiments. The approach uses a pair of optical fibers with large core diameters and high numerical apertures to maximize light collection efficiency and to moderate the mechanical precision required for alignment. Bench tests indicate that efficiency reduction is almost entirely due to reflective losses at the fiber ends, while losses due to fiber misalignment have virtually been eliminated. Photon-map imaging with nanometer features is demonstrated on a stepped Au(111) surface with signal rates exceeding 10(4) counts/s.

Sensing systems using chip-based spectrometers

NASA Astrophysics Data System (ADS)

Nitkowski, Arthur; Preston, Kyle J.; Sherwood-Droz, Nicolás.; Behr, Bradford B.; Bismilla, Yusuf; Cenko, Andrew T.; DesRoches, Brandon; Meade, Jeffrey T.; Munro, Elizabeth A.; Slaa, Jared; Schmidt, Bradley S.; Hajian, Arsen R.

2014-06-01

Tornado Spectral Systems has developed a new chip-based spectrometer called OCTANE, the Optical Coherence Tomography Advanced Nanophotonic Engine, built using a planar lightwave circuit with integrated waveguides fabricated on a silicon wafer. While designed for spectral domain optical coherence tomography (SD-OCT) systems, the same miniaturized technology can be applied to many other spectroscopic applications. The field of integrated optics enables the design of complex optical systems which are monolithically integrated on silicon chips. The form factors of these systems can be significantly smaller, more robust and less expensive than their equivalent free-space counterparts. Fabrication techniques and material systems developed for microelectronics have previously been adapted for integrated optics in the telecom industry, where millions of chip-based components are used to power the optical backbone of the internet. We have further adapted the photonic technology platform for spectroscopy applications, allowing unheard-of economies of scale for these types of optical devices. Instead of changing lenses and aligning systems, these devices are accurately designed programmatically and are easily customized for specific applications. Spectrometers using integrated optics have large advantages in systems where size, robustness and cost matter: field-deployable devices, UAVs, UUVs, satellites, handheld scanning and more. We will discuss the performance characteristics of our chip-based spectrometers and the type of spectral sensing applications enabled by this technology.

Fluorescence image excited by a scanning UV-LED light

NASA Astrophysics Data System (ADS)

Tsai, Hsin-Yi; Chen, Yi-Ju; Huang, Kuo-Cheng

2013-03-01

An optical scanning system using UV-LED light to induced fluorescence technology can enhance a fluorescence image significantly in a short period. It has several advantages such as lower power consumption, no scattering effect in skins, and multilayer images can be obtained to analyze skin disease. From the experiment results, the light intensity increases with increase spot size and decrease scanning speed, but the image resolution is oppositely. Moreover, the system could be widely used in clinical diagnosis and photodynamic therapy for skin disease because even the irradiated time of fluorescence substance is short but it will provide accurately positioning of fluorescence object.

Optical CT imaging of solid radiochromic dosimeters in mismatched refractive index solutions using a scanning laser and large area detector.

PubMed

Dekker, Kurtis H; Battista, Jerry J; Jordan, Kevin J

2016-08-01

The practical use of the PRESAGE® solid plastic dosimeter is limited by the inconvenience of immersing it in high-viscosity oils to achieve refractive index matching for optical computed tomography (CT) scanning. The oils are slow to mix and difficult to clean from surfaces, and the dosimeter rotation can generate dynamic Schlieren inhomogeneity patterns in the reference liquid, limiting the rotational and overall scan speed. Therefore, it would be beneficial if lower-viscosity, water-based solutions with slightly unmatched refractive index could be used instead. The purpose of this work is to demonstrate the feasibility of allowing mismatched conditions when using a scanning laser system with a large acceptance angle detector. A fiducial-based ray path measurement technique is combined with an iterative CT reconstruction algorithm to reconstruct images. A water based surrounding liquid with a low viscosity was selected for imaging PRESAGE® solid dosimeters. Liquid selection was optimized to achieve as high a refractive index as possible while avoiding rotation-induced Schlieren effects. This led to a refractive index mismatch of 6% between liquid and dosimeters. Optical CT scans were performed with a fan-beam scanning-laser optical CT system with a large area detector to capture most of the refracted rays. A fiducial marker placed on the wall of a cylindrical sample occludes a given light ray twice. With knowledge of the rotation angle and the radius of the cylindrical object, the actual internal path of each ray through the dosimeter can be calculated. Scans were performed with 1024 projections of 512 data samples each, and rays were rebinned to form 512 parallel-beam projections. Reconstructions were performed on a 512 × 512 grid using 100 iterations of the SIRT iterative CT algorithm. Proof of concept was demonstrated with a uniformly attenuating solution phantom. PRESAGE® dosimeters (11 cm diameter) were irradiated with Cobalt-60 irradiator to achieve either a uniform dose or a 2-level "step-dose" pattern. With 6% refractive index mismatching, a circular field of view of 85% of the diameter of a cylindrical sample can be reconstructed accurately. Reconstructed images of the test solution phantom were uniform (within 3%) inside this radius. However, the dose responses of the PRESAGE® samples were not spatially uniform, with variations of at least 5% in sensitivity. The variation appears as a "cupping" artifact with less sensitivity in the middle than at the periphery of the PRESAGE® cylinder. Polarization effects were also detected for these samples. The fiducial-based ray path measurement scheme, coupled with an iterative reconstruction algorithm, enabled optical CT scanning of PRESAGE® dosimeters immersed in mismatched refractive index solutions. However, improvements to PRESAGE® dose response uniformity are required.

A fast dual wavelength laser beam fluid-less optical CT scanner for radiotherapy 3D gel dosimetry I: design and development

NASA Astrophysics Data System (ADS)

Ramm, Daniel

2018-02-01

Three dimensional dosimetry by optical CT readout of radiosensitive gels or solids has previously been indicated as a solution for measurement of radiotherapy 3D dose distributions. The clinical uptake of these dosimetry methods has been limited, partly due to impracticalities of the optical readout such as the expertise and labour required for refractive index fluid matching. In this work a fast laser beam optical CT scanner is described, featuring fluid-less and dual wavelength operation. A second laser with a different wavelength is used to provide an alternative reference scan to the commonly used pre-irradiation scan. Transmission data for both wavelengths is effectively acquired simultaneously, giving a single scan process. Together with the elimination of refractive index fluid matching issues, scanning practicality is substantially improved. Image quality and quantitative accuracy were assessed for both dual and single wavelength methods. The dual wavelength scan technique gave improvements in uniformity of reconstructed optical attenuation coefficients in the sample 3D volume. This was due to a reduction of artefacts caused by scan to scan changes. Optical attenuation measurement accuracy was similar for both dual and single wavelength modes of operation. These results established the basis for further work on dosimetric performance.

Scientific Applications of Optical Instruments to Materials Research

NASA Technical Reports Server (NTRS)

Witherow, William K.

1997-01-01

Microgravity is a unique environment for materials and biotechnology processing. Microgravity minimizes or eliminates some of the effects that occur in one g. This can lead to the production of new materials or crystal structures. It is important to understand the processes that create these new materials. Thus, experiments are designed so that optical data collection can take place during the formation of the material. This presentation will discuss scientific application of optical instruments at MSFC. These instruments include a near-field scanning optical microscope, a miniaturized holographic system, and a phase-shifting interferometer.

Imaging mouse cerebellum with serial optical coherence scanner (Conference Presentation)

NASA Astrophysics Data System (ADS)

Liu, Chao J.; Williams, Kristen; Orr, Harry; Taner, Akkin

2017-02-01

We present the serial optical coherence scanner (SOCS), which consists of a polarization sensitive optical coherence tomography and a vibratome with associated controls for serial imaging, to visualize the cerebellum and adjacent brainstem of mouse. The cerebellar cortical layers and white matter are distinguished by using intrinsic optical contrasts. Images from serial scans reveal the large-scale anatomy in detail and map the nerve fiber pathways in the cerebellum and adjacent brainstem. The optical system, which has 5.5 μm axial resolution, utilizes a scan lens or a water-immersion microscope objective resulting in 10 μm or 4 μm lateral resolution, respectively. The large-scale brain imaging at high resolution requires an efficient way to collect large datasets. It is important to improve the SOCS system to deal with large-scale and large number of samples in a reasonable time. The imaging and slicing procedure for a section took about 4 minutes due to a low speed of the vibratome blade to maintain slicing quality. SOCS has potential to investigate pathological changes and monitor the effects of therapeutic drugs in cerebellar diseases such as spinocerebellar ataxia 1 (SCA1). The SCA1 is a neurodegenerative disease characterized by atrophy and eventual loss of Purkinje cells from the cerebellar cortex, and the optical contrasts provided by SOCS is being evaluated for biomarkers of the disease.

Development of large field-of-view two photon microscopy for imaging mouse cortex (Conference Presentation)

NASA Astrophysics Data System (ADS)

Bumstead, Jonathan; Côté, Daniel C.; Culver, Joseph P.

2017-02-01

Spontaneous neuronal activity has been measured at cellular resolution in mice, zebrafish, and C. elegans using optical sectioning microscopy techniques, such as light sheet microscopy (LSM) and two photon microscopy (TPM). Recent improvements in these modalities and genetically encoded calcium indicators (GECI's) have enabled whole brain imaging of calcium dynamics in zebrafish and C. elegans. However, these whole brain microscopy studies have not been extended to mice due to the limited field of view (FOV) of TPM and the cumbersome geometry of LSM. Conventional TPM is restricted to diffraction limited imaging over this small FOV (around 500 x 500 microns) due to the use of high magnification objectives (e.g. 1.0 NA; 20X) and the aberrations introduced by relay optics used in scanning the beam across the sample. To overcome these limitations, we have redesigned the entire optical path of the two photon microscope (scanning optics and objective lens) to support a field of view of Ø7 mm with relatively high spatial resolution (<10 microns). Using optical engineering software Zemax, we designed our system with commercially available optics that minimize astigmatism, field curvature, chromatic focal shift, and vignetting. Performance of the system was also tested experimentally with fluorescent beads in agarose, fixed samples, and in vivo structural imaging. Our large-FOV TPM provides a modality capable of studying distributed brain networks in mice at cellular resolution.

AOSLO: from benchtop to clinic

NASA Astrophysics Data System (ADS)

Zhang, Yuhua; Poonja, Siddharth; Roorda, Austin

2006-08-01

We present a clinically deployable adaptive optics scanning laser ophthalmoscope (AOSLO) that features micro-electro-mechanical (MEMS) deformable mirror (DM) based adaptive optics (AO) and low coherent light sources. With the miniaturized optical aperture of a μDMS-Multi TM MEMS DM (Boston Micromachines Corporation, Watertown, MA), we were able to develop a compact and robust AOSLO optical system that occupies a 50 cm X 50 cm area on a mobile optical table. We introduced low coherent light sources, which are superluminescent laser diodes (SLD) at 680 nm with 9 nm bandwidth and 840 nm with 50 nm bandwidth, in confocal scanning ophthalmoscopy to eliminate interference artifacts in the images. We selected a photo multiplier tube (PMT) for photon signal detection and designed low noise video signal conditioning circuits. We employed an acoustic-optical (AOM) spatial light modulator to modulate the light beam so that we could avoid unnecessary exposure to the retina or project a specific stimulus pattern onto the retina. The MEMS DM based AO system demonstrated robust performance. The use of low coherent light sources effectively mitigated the interference artifacts in the images and yielded high-fidelity retinal images of contiguous cone mosaic. We imaged patients with inherited retinal degenerations including cone-rod dystrophy (CRD) and retinitis pigmentosa (RP). We have produced high-fidelity, real-time, microscopic views of the living human retina for healthy and diseased eyes.

Advanced electric-field scanning probe lithography on molecular resist using active cantilever

NASA Astrophysics Data System (ADS)

Kaestner, Marcus; Aydogan, Cemal; Lipowicz, Hubert-Seweryn; Ivanov, Tzvetan; Lenk, Steve; Ahmad, Ahmad; Angelov, Tihomir; Reum, Alexander; Ishchuk, Valentyn; Atanasov, Ivaylo; Krivoshapkina, Yana; Hofer, Manuel; Holz, Mathias; Rangelow, Ivo W.

2015-03-01

The routine "on demand" fabrication of features smaller than 10 nm opens up new possibilities for the realization of many novel nanoelectronic, NEMS, optical and bio-nanotechnology-based devices. Based on the thermally actuated, piezoresistive cantilever technology we have developed a first prototype of a scanning probe lithography (SPL) platform able to image, inspect, align and pattern features down to single digit nano regime. The direct, mask-less patterning of molecular resists using active scanning probes represents a promising path circumventing the problems in today's radiation-based lithography. Here, we present examples of practical applications of the previously published electric field based, current-controlled scanning probe lithography on molecular glass resist calixarene by using the developed tabletop SPL system. We demonstrate the application of a step-and-repeat scanning probe lithography scheme including optical as well as AFM based alignment and navigation. In addition, sequential read-write cycle patterning combining positive and negative tone lithography is shown. We are presenting patterning over larger areas (80 x 80 μm) and feature the practical applicability of the lithographic processes.

Model MTF for the mosaic window

NASA Astrophysics Data System (ADS)

Xing, Zhenchong; Hong, Yongfeng; Zhang, Bao

2017-10-01

An electro-optical targeting system mounted either within an airframe or housed in separate pods requires a window to form an environmental barrier to the outside world. In current practice, such windows usually use a mosaic or segmented window. When scanning the target, internally gimbaled systems sweep over the window, which can affect the modulation transfer function (MTF) due to wave-front division and optical path differences arising from the thickness/wedge differences between panes. In this paper, a mathematical model of the MTF of the mosaic window is presented that allows an analysis of influencing factors; we show how the model may be integrated into ZEMAX® software for optical design. The model can be used to guide both the design and the tolerance analysis of optical systems that employ a mosaic window.

Copying of holograms by spot scanning approach.

PubMed

Okui, Makoto; Wakunami, Koki; Oi, Ryutaro; Ichihashi, Yasuyuki; Jackin, Boaz Jessie; Yamamoto, Kenji

2018-05-20

To replicate holograms, contact copying has conventionally been used. In this approach, a photosensitive material is fixed together with a master hologram and illuminated with a coherent beam. This method is simple and enables high-quality copies; however, it requires a large optical setup for large-area holograms. In this paper, we present a new method of replicating holograms that uses a relatively compact optical system even for the replication of large holograms. A small laser spot that irradiates only part of the hologram is used to reproduce the hologram by scanning the spot over the whole area of the hologram. We report on the results of experiments carried out to confirm the copy quality, along with a guide to design scanning conditions. The results show the potential effectiveness of the large-area hologram replication technology using a relatively compact apparatus.

Development of an ultrasound microscope combined with optical microscope for multiparametric characterization of a single cell.

PubMed

Arakawa, Mototaka; Shikama, Joe; Yoshida, Koki; Nagaoka, Ryo; Kobayashi, Kazuto; Saijo, Yoshifumi

2015-09-01

Biomechanics of the cell has been gathering much attention because it affects the pathological status in atherosclerosis and cancer. In the present study, an ultrasound microscope system combined with optical microscope for characterization of a single cell with multiple ultrasound parameters was developed. The central frequency of the transducer was 375 MHz and the scan area was 80 × 80 μm with up to 200 × 200 sampling points. An inverted optical microscope was incorporated in the design of the system, allowing for simultaneous optical observations of cultured cells. Two-dimensional mapping of multiple ultrasound parameters, such as sound speed, attenuation, and acoustic impedance, as well as the thickness, density, and bulk modulus of specimen/cell under investigation, etc., was realized by the system. Sound speed and thickness of a 3T3-L1 fibroblast cell were successfully obtained by the system. The ultrasound microscope system combined with optical microscope further enhances our understanding of cellular biomechanics.

Design of an electron projection system with slider lenses and multiple beams

NASA Astrophysics Data System (ADS)

Moonen, Daniel; Leunissen, Peter L. H. A.; de Jager, Patrick W.; Kruit, Pieter; Bleeker, Arno J.; Van der Mast, Karel D.

2002-07-01

The commercial applicability of electron beam projection lithography systems may be limited at high resolution because of low throughput. The main limitations to the throughput are: (i) Beam current. The Coulomb interaction between electrons result in an image blue. Therefore less beam current can be allowed at higher resolution, impacting the illuminate time of the wafer. (ii) Exposure field size. Early attempts to improve throughput with 'full chip' electron beam projection systems failed, because the system suffered from large off-axis aberrations of the electron optics, which severely restricted the useful field size. This has impact on the overhead time. A new type of projection optics will be proposed in this paper to overcome both limits. A slider lens is proposed that allows an effective field that is much larger than schemes proposed by SCALPEL and PREVAIL. The full width of the die can be exposed without mechanical scanning by sliding the beam through the slit-like bore of the lens. Locally, at the beam position, a 'round'-lens field is created with a combination of a rectangular magnetic field and quadruples that are positioned inside the lens. A die can now be exposed during a single mechanical scan as in state-of-the-art light optical tools. The total beam current can be improved without impact on the Coulomb interaction blur by combining several beams in a single lithography system if these beams do not interfere with each other. Several optical layouts have been proposed that combined up to 5 beams in a projection system consisting of a doublet of slider lenses. This type of projection optics has a potential throughput of 50 WPH at 45 nm with a resist sensitivity of 6 (mu) C/cm2.

Final report: Mapping Interactions in Hybrid Systems with Active Scanning Probes

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

Berezovsky, Jesse

2017-09-29

This project aimed to study and map interactions between components of hybrid nanodevices using a novel scanning probe approach. To enable this work, we initially constructed a flexible experimental apparatus allowing for simultaneous scanning probe and confocal optical microscopy measurements. This setup was first used for all-optical measurements of nanostructures, with the focus then shifting to hybrid devices in which single coherent electron spins are coupled to micron-scale ferromagnetic elements, which may prove useful for addressing single spins, enhanced sensing, or spin-wave-mediated coupling of spins for quantum information applications. A significant breakthrough was the realization that it is not necessarymore » to fabricate a magnetic structure on a scanning probe – instead a ferromagnetic vortex core can act as an integrated, solid state, scanning probe. The core of the vortex produces a very strong, localized fringe field which can be used analogously to an MFM tip. Unlike a traditional MFM tip, however, the vortex core is scanned within an integrated device (eliminating drift), and can be moved on vastly faster timescales. This approach allows the detailed investigation of interactions between single spins and complex driven ferromagnetic dynamics.« less

Internal scanning method as unique imaging method of optical vortex scanning microscope

NASA Astrophysics Data System (ADS)

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

2018-06-01

The internal scanning method is specific for the optical vortex microscope. It allows to move the vortex point inside the focused vortex beam with nanometer resolution while the whole beam stays in place. Thus the sample illuminated by the focused vortex beam can be scanned just by the vortex point. We show that this method enables high resolution imaging. The paper presents the preliminary experimental results obtained with the first basic image recovery procedure. A prospect of developing more powerful tools for topography recovery with the optical vortex scanning microscope is discussed shortly.

Laser scanning saturated structured illumination microscopy based on phase modulation

NASA Astrophysics Data System (ADS)

Huang, Yujia; Zhu, Dazhao; Jin, Luhong; Kuang, Cuifang; Xu, Yingke; Liu, Xu

2017-08-01

Wide-field saturated structured illumination microscopy has not been widely used due to the requirement of high laser power. We propose a novel method called laser scanning saturated structured illumination microscopy (LS-SSIM), which introduces high order of harmonics frequency and greatly reduces the required laser power for SSIM imaging. To accomplish that, an excitation PSF with two peaks is generated and scanned along different directions on the sample. Raw images are recorded cumulatively by a CCD detector and then reconstructed to form a high-resolution image with extended optical transfer function (OTF). Our theoretical analysis and simulation results show that LS-SSIM method reaches a resolution of 0.16 λ, equivalent to 2.7-fold resolution than conventional wide-field microscopy. In addition, LS-SSIM greatly improves the optical sectioning capability of conventional wide-field illumination system by diminishing our-of-focus light. Furthermore, this modality has the advantage of implementation in multi-photon microscopy with point scanning excitation to image samples in greater depths.

U-10Mo Sample Preparation and Examination using Optical and Scanning Electron Microscopy

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

Prabhakaran, Ramprashad; Joshi, Vineet V.; Rhodes, Mark A.

2016-10-01

The purpose of this document is to provide guidelines to prepare specimens of uranium alloyed with 10 weight percent molybdenum (U-10Mo) for optical metallography and scanning electron microscopy. This document also provides instructions to set up an optical microscope and a scanning electron microscope to analyze U-10Mo specimens and to obtain the required information.

U-10Mo Sample Preparation and Examination using Optical and Scanning Electron Microscopy

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

Prabhakaran, Ramprashad; Joshi, Vineet V.; Rhodes, Mark A.

2016-03-30

The purpose of this document is to provide guidelines to prepare specimens of uranium alloyed with 10 weight percent molybdenum (U-10Mo) for optical metallography and scanning electron microscopy. This document also provides instructions to set up an optical microscope and a scanning electron microscope to analyze U-10Mo specimens and to obtain the required information.

Holographic optics: Design and applications; Proceedings of the Meeting, Los Angeles, CA, Jan. 13, 14, 1988

NASA Astrophysics Data System (ADS)

Cindrich, Ivan

1988-01-01

The present conference discusses topics in design and analysis methods for holographic optics, as well as their materials and fabrication techniques and their applications. Attention is given to novel holographic helmet display designs, holographic optics optimization by damped least-squares and wavefront matching, the optical performance of holographic kinoforms, a cascaded transmission hologram for HUDs, a multilayer thin film simulation of volume holograms, and the DMP-128 holographic-recording photopolymer. Also discussed are a uniform hologram construction layout, diffractive optics with incoherent optical systems, holographic laser-protective eyewear, novel applications for embossed holograms, and hologon deflectors with dispersive optical elements for scan line bow correction.

A robotic multi-channel platform for interstitial photodynamic therapy

PubMed Central

Sharikova, Anna V.; Finlay, Jarod C.; Dimofte, Andreea; Zhu, Timothy C.

2015-01-01

A custom-made robotic multichannel platform for interstitial photodynamic therapy (PDT) and diffuse optical tomography (DOT) was developed and tested in a phantom experiment. The system, which was compatible with the operating room (OR) environment, had 16 channels for independent positioning of light sources and/or isotropic detectors in separate catheters. Each channel’s motor had an optical encoder for position feedback, with resolution of 1.5 mm, and a maximum speed of 5 cm/s. Automatic calibration of detector positions was implemented using an optical diode beam that defined the starting position of each motor, and by means of feedback algorithms controlling individual channels. As a result, the accuracy of zero position of 0.1 mm for all channels was achieved. We have also employed scanning procedures where detectors automatically covered the appropriate range around source positions. Thus, total scan time for a typical optical properties (OP) measurement throughout the phantom was about 1.5 minutes with point sources. The OP were determined based on the measured light fluence rates. These enhancements allow a tremendous improvement of treatment quality for a bulk tumor compared to the systems employed in previous clinical trials. PMID:25914794

The Scanning Optical Microscope.

ERIC Educational Resources Information Center

Sheppard, C. J. R.

1978-01-01

Describes the principle of the scanning optical microscope and explains its advantages over the conventional microscope in the improvement of resolution and contrast, as well as the possibility of producing a picture from optical harmonies generated within the specimen.

Cycloid scanning for wide field optical coherence tomography endomicroscopy and angiography in vivo

PubMed Central

Liang, Kaicheng; Wang, Zhao; Ahsen, Osman O.; Lee, Hsiang-Chieh; Potsaid, Benjamin M.; Jayaraman, Vijaysekhar; Cable, Alex; Mashimo, Hiroshi; Li, Xingde; Fujimoto, James G.

2018-01-01

Devices that perform wide field-of-view (FOV) precision optical scanning are important for endoscopic assessment and diagnosis of luminal organ disease such as in gastroenterology. Optical scanning for in vivo endoscopic imaging has traditionally relied on one or more proximal mechanical actuators, limiting scan accuracy and imaging speed. There is a need for rapid and precise two-dimensional (2D) microscanning technologies to enable the translation of benchtop scanning microscopies to in vivo endoscopic imaging. We demonstrate a new cycloid scanner in a tethered capsule for ultrahigh speed, side-viewing optical coherence tomography (OCT) endomicroscopy in vivo. The cycloid capsule incorporates two scanners: a piezoelectrically actuated resonant fiber scanner to perform a precision, small FOV, fast scan and a micromotor scanner to perform a wide FOV, slow scan. Together these scanners distally scan the beam circumferentially in a 2D cycloid pattern, generating an unwrapped 1 mm × 38 mm strip FOV. Sequential strip volumes can be acquired with proximal pullback to image centimeter-long regions. Using ultrahigh speed 1.3 μm wavelength swept-source OCT at a 1.17 MHz axial scan rate, we imaged the human rectum at 3 volumes/s. Each OCT strip volume had 166 × 2322 axial scans with 8.5 μm axial and 30 μm transverse resolution. We further demonstrate OCT angiography at 0.5 volumes/s, producing volumetric images of vasculature. In addition to OCT applications, cycloid scanning promises to enable precision 2D optical scanning for other imaging modalities, including fluorescence confocal and nonlinear microscopy. PMID:29682598

In situ industrial applications of optics; Proceedings of the Meeting, Brussels, Belgium, June 25-27, 1986

NASA Astrophysics Data System (ADS)

Ebbeni, Jean

Included in this volume are papers on real-time image enhancement by simple video systems, automatic identification and data collection via barcode laser scanning, the optimization of the cutting up of a strip of float glass, optical sensors for factory automation, and the use of a digital theodolite with infrared radiation. Attention is also given to ISIS (integrated shape imaging system), a new system for follow-up of scoliosis; optical diffraction extensometers; a cross-spectrum technique for high-sensitivity remote vibration analysis by optical interferometry; the compensation and measurement of any motion of three-dimensional objects in holographic interferometry; and stereoscreen. Additional papers are on holographic double pulse YAG lasers, miniature optic connectors, stress-field analysis in an adhesively bonded joint with laser photoelasticimetry, and the locking of the light pulse delay in externally triggered gas lasers.

Sensors and sensor systems for guidance and navigation II; Proceedings of the Meeting, Orlando, FL, Apr. 22, 23, 1992

NASA Astrophysics Data System (ADS)

Welch, Sharon S.

Topics discussed in this volume include aircraft guidance and navigation, optics for visual guidance of aircraft, spacecraft and missile guidance and navigation, lidar and ladar systems, microdevices, gyroscopes, cockpit displays, and automotive displays. Papers are presented on optical processing for range and attitude determination, aircraft collision avoidance using a statistical decision theory, a scanning laser aircraft surveillance system for carrier flight operations, star sensor simulation for astroinertial guidance and navigation, autonomous millimeter-wave radar guidance systems, and a 1.32-micron long-range solid state imaging ladar. Attention is also given to a microfabricated magnetometer using Young's modulus changes in magnetoelastic materials, an integrated microgyroscope, a pulsed diode ring laser gyroscope, self-scanned polysilicon active-matrix liquid-crystal displays, the history and development of coated contrast enhancement filters for cockpit displays, and the effect of the display configuration on the attentional sampling performance. (For individual items see A93-28152 to A93-28176, A93-28178 to A93-28180)

SPED light sheet microscopy: fast mapping of biological system structure and function

PubMed Central

Tomer, Raju; Lovett-Barron, Matthew; Kauvar, Isaac; Andalman, Aaron; Burns, Vanessa M.; Sankaran, Sethuraman; Grosenick, Logan; Broxton, Michael; Yang, Samuel; Deisseroth, Karl

2016-01-01

The goal of understanding living nervous systems has driven interest in high-speed and large field-of-view volumetric imaging at cellular resolution. Light-sheet microscopy approaches have emerged for cellular-resolution functional brain imaging in small organisms such as larval zebrafish, but remain fundamentally limited in speed. Here we have developed SPED light sheet microscopy, which combines large volumetric field-of-view via an extended depth of field with the optical sectioning of light sheet microscopy, thereby eliminating the need to physically scan detection objectives for volumetric imaging. SPED enables scanning of thousands of volumes-per-second, limited only by camera acquisition rate, through the harnessing of optical mechanisms that normally result in unwanted spherical aberrations. We demonstrate capabilities of SPED microscopy by performing fast sub-cellular resolution imaging of CLARITY mouse brains and cellular-resolution volumetric Ca2+ imaging of entire zebrafish nervous systems. Together, SPED light sheet methods enable high-speed cellular-resolution volumetric mapping of biological system structure and function. PMID:26687363

High throughput optical scanner

DOEpatents

Basiji, David A.; van den Engh, Gerrit J.

2001-01-01

A scanning apparatus is provided to obtain automated, rapid and sensitive scanning of substrate fluorescence, optical density or phosphorescence. The scanner uses a constant path length optical train, which enables the combination of a moving beam for high speed scanning with phase-sensitive detection for noise reduction, comprising a light source, a scanning mirror to receive light from the light source and sweep it across a steering mirror, a steering mirror to receive light from the scanning mirror and reflect it to the substrate, whereby it is swept across the substrate along a scan arc, and a photodetector to receive emitted or scattered light from the substrate, wherein the optical path length from the light source to the photodetector is substantially constant throughout the sweep across the substrate. The optical train can further include a waveguide or mirror to collect emitted or scattered light from the substrate and direct it to the photodetector. For phase-sensitive detection the light source is intensity modulated and the detector is connected to phase-sensitive detection electronics. A scanner using a substrate translator is also provided. For two dimensional imaging the substrate is translated in one dimension while the scanning mirror scans the beam in a second dimension. For a high throughput scanner, stacks of substrates are loaded onto a conveyor belt from a tray feeder.

In-vivo digital wavefront sensing using swept source OCT

PubMed Central

Kumar, Abhishek; Wurster, Lara M.; Salas, Matthias; Ginner, Laurin; Drexler, Wolfgang; Leitgeb, Rainer A.

2017-01-01

Sub-aperture based digital adaptive optics is demonstrated in a fiber based point scanning optical coherence tomography system using a 1060 nm swept source laser. To detect optical aberrations in-vivo, a small lateral field of view of ~150×150 μm2 is scanned on the sample at a high volume rate of 17 Hz (~1.3 kHz B-scan rate) to avoid any significant lateral and axial motion of the sample, and is used as a “guide star” for the sub-aperture based DAO. The proof of principle is demonstrated using a micro-beads phantom sample, wherein a significant root mean square wavefront error (RMS WFE) of 1.48 waves (> 1μm) is detected. In-vivo aberration measurement with a RMS WFE of 0.33 waves, which is ~5 times higher than the Marechal’s criterion of 1/14 waves for the diffraction limited performance, is shown for a human retinal OCT. Attempt has been made to validate the experimental results with the conventional Shack-Hartmann wavefront sensor within reasonable limitations. PMID:28717573

Towards the development of a hybrid-integrated chip interferometer for online surface profile measurements

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

Kumar, P.; Martin, H.; Jiang, X.

Non-destructive testing and online measurement of surface features are pressing demands in manufacturing. Thus optical techniques are gaining importance for characterization of complex engineering surfaces. Harnessing integrated optics for miniaturization of interferometry systems onto a silicon wafer and incorporating a compact optical probe would enable the development of a handheld sensor for embedded metrology applications. In this work, we present the progress in the development of a hybrid photonics based metrology sensor device for online surface profile measurements. The measurement principle along with test and measurement results of individual components has been presented. For non-contact measurement, a spectrally encoded lateralmore » scanning probe based on the laser scanning microscopy has been developed to provide fast measurement with lateral resolution limited to the diffraction limit. The probe demonstrates a lateral resolution of ∼3.6 μm while high axial resolution (sub-nanometre) is inherently achieved by interferometry. Further the performance of the hybrid tuneable laser and the scanning probe was evaluated by measuring a standard step height sample of 100 nm.« less

A versatile optical profilometer based on conoscopic holography sensors for acquisition of specular and diffusive surfaces in artworks

NASA Astrophysics Data System (ADS)

Gaburro, Nicola; Marchioro, Giacomo; Daffara, Claudia

2017-07-01

Surface metrology of artworks requires the design of suitable devices for in-situ non-destructive measurement together with reliable procedures for an effective analysis of such non-engineered variegate objects. To advance the state-of-the-art it has been implemented a versatile optical micro-profilometry taking advantage of the adapt- ability of conoscopic holography sensors, able to operate with irregular shapes and composite materials (diffusive, specular, and polychrome) of artworks. The scanning technique is used to obtain wide field and high spatially resolved areal profilometry. The prototype has a modular scheme based on a set of conoscopic sensors, extending the typical design based on a scanning stage and a single probe with a limited bandwidth, thus allowing the collection of heights data from surface with different scales and materials with variegate optical response. The system was optimized by characterizing the quality of the measurement with the probes triggered in continuous scanning modality. The results obtained on examples of cultural heritage objects (2D paintings, 3D height-relief) and materials (pictorial, metallic) demonstrate the versatility of the implemented device.

Real-time microstructural and functional imaging and image processing in optical coherence tomography

NASA Astrophysics Data System (ADS)

Westphal, Volker

Optical Coherence Tomography (OCT) is a noninvasive optical imaging technique that allows high-resolution cross-sectional imaging of tissue microstructure, achieving a spatial resolution of about 10 mum. OCT is similar to B-mode ultrasound (US) except that it uses infrared light instead of ultrasound. In contrast to US, no coupling gel is needed, simplifying the image acquisition. Furthermore, the fiber optic implementation of OCT is compatible with endoscopes. In recent years, the transition from slow imaging, bench-top systems to real-time clinical systems has been under way. This has lead to a variety of applications, namely in ophthalmology, gastroenterology, dermatology and cardiology. First, this dissertation will demonstrate that OCT is capable of imaging and differentiating clinically relevant tissue structures in the gastrointestinal tract. A careful in vitro correlation study between endoscopic OCT images and corresponding histological slides was performed. Besides structural imaging, OCT systems were further developed for functional imaging, as for example to visualize blood flow. Previously, imaging flow in small vessels in real-time was not possible. For this research, a new processing scheme similar to real-time Doppler in US was introduced. It was implemented in dedicated hardware to allow real-time acquisition and overlayed display of blood flow in vivo. A sensitivity of 0.5mm/s was achieved. Optical coherence microscopy (OCM) is a variation of OCT, improving the resolution even further to a few micrometers. Advances made in the OCT scan engine for the Doppler setup enabled real-time imaging in vivo with OCM. In order to generate geometrical correct images for all the previous applications in real-time, extensive image processing algorithms were developed. Algorithms for correction of distortions due to non-telecentric scanning, nonlinear scan mirror movements, and refraction were developed and demonstrated. This has led to interesting new applications, as for example in imaging of the anterior segment of the eye.

Conjugation of both on-axis and off-axis light in Nipkow disk confocal microscope to increase availability of incoherent light source.

PubMed

Saito, Kenta; Arai, Yoshiyuki; Zhang, Jize; Kobayashi, Kentaro; Tani, Tomomi; Nagai, Takeharu

2011-01-01

Laser-scanning confocal microscopy has been employed for exploring structures at subcellular, cellular and tissue level in three dimensions. To acquire the confocal image, a coherent light source, such as laser, is generally required in conventional single-point scanning microscopy. The illuminating beam must be focused onto a small spot with diffraction-limited size, and this determines the spatial resolution of the microscopy system. In contrast, multipoint scanning confocal microscopy using a Nipkow disk enables the use of an incoherent light source. We previously demonstrated successful application of a 100 W mercury arc lamp as a light source for the Yokogawa confocal scanner unit in which a microlens array was coupled with a Nipkow disk to focus the collimated incident light onto a pinhole (Saito et al., Cell Struct. Funct., 33: 133-141, 2008). However, transmission efficiency of incident light through the pinhole array was low because off-axis light, the major component of the incident light, was blocked by the non-aperture area of the disk. To improve transmission efficiency, we propose an optical system in which off-axis light is able to be transmitted through pinholes surrounding the pinhole located on the optical axis of the collimator lens. This optical system facilitates the use of not only the on-axis but also the off-axis light such that the available incident light is considerably improved. As a result, we apply the proposed system to high-speed confocal and multicolor imaging both with a satisfactory signal-to-noise ratio.

Precision targeting with a tracking adaptive optics scanning laser ophthalmoscope

NASA Astrophysics Data System (ADS)

Hammer, Daniel X.; Ferguson, R. Daniel; Bigelow, Chad E.; Iftimia, Nicusor V.; Ustun, Teoman E.; Noojin, Gary D.; Stolarski, David J.; Hodnett, Harvey M.; Imholte, Michelle L.; Kumru, Semih S.; McCall, Michelle N.; Toth, Cynthia A.; Rockwell, Benjamin A.

2006-02-01

Precise targeting of retinal structures including retinal pigment epithelial cells, feeder vessels, ganglion cells, photoreceptors, and other cells important for light transduction may enable earlier disease intervention with laser therapies and advanced methods for vision studies. A novel imaging system based upon scanning laser ophthalmoscopy (SLO) with adaptive optics (AO) and active image stabilization was designed, developed, and tested in humans and animals. An additional port allows delivery of aberration-corrected therapeutic/stimulus laser sources. The system design includes simultaneous presentation of non-AO, wide-field (~40 deg) and AO, high-magnification (1-2 deg) retinal scans easily positioned anywhere on the retina in a drag-and-drop manner. The AO optical design achieves an error of <0.45 waves (at 800 nm) over +/-6 deg on the retina. A MEMS-based deformable mirror (Boston Micromachines Inc.) is used for wave-front correction. The third generation retinal tracking system achieves a bandwidth of greater than 1 kHz allowing acquisition of stabilized AO images with an accuracy of ~10 μm. Normal adult human volunteers and animals with previously-placed lesions (cynomolgus monkeys) were tested to optimize the tracking instrumentation and to characterize AO imaging performance. Ultrafast laser pulses were delivered to monkeys to characterize the ability to precisely place lesions and stimulus beams. Other advanced features such as real-time image averaging, automatic highresolution mosaic generation, and automatic blink detection and tracking re-lock were also tested. The system has the potential to become an important tool to clinicians and researchers for early detection and treatment of retinal diseases.

Biochip scanner device

DOEpatents

Perov, Alexander; Belgovskiy, Alexander I.; Mirzabekov, Andrei D.

2001-01-01

A biochip scanner device used to detect and acquire fluorescence signal data from biological microchips or biochips and method of use are provided. The biochip scanner device includes a laser for emitting a laser beam. A modulator, such as an optical chopper modulates the laser beam. A scanning head receives the modulated laser beam and a scanning mechanics coupled to the scanning head moves the scanning head relative to the biochip. An optical fiber delivers the modulated laser beam to the scanning head. The scanning head collects the fluorescence light from the biochip, launches it into the same optical fiber, which delivers the fluorescence into a photodetector, such as a photodiode. The biochip scanner device is used in a row scanning method to scan selected rows of the biochip with the laser beam size matching the size of the immobilization site.

Science & Technology Review October 2007

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

Chinn, D J

Livermore researchers won five R&D 100 awards in R&D Magazine's annual competition for the top 100 industrial innovations worldwide. This issue of Science & Technology Review highlights the award-winning technologies: noninvasive pneumothorax detector, microelectromechanical system-based adaptive optics scanning laser ophthalmoscope, large-area imager, hyper library of linear solvers, and continuous-phase-plate optics system manufactured using magnetorheological finishing. Since 1978, Laboratory researchers have received 118 R&D 100 awards. The R&D 100 logo (on the cover and p 1) is reprinted courtesy of R&D Magazine.

Highly integrated optical phased arrays: photonic integrated circuits for optical beam shaping and beam steering

NASA Astrophysics Data System (ADS)

Heck, Martijn J. R.

2017-01-01

Technologies for efficient generation and fast scanning of narrow free-space laser beams find major applications in three-dimensional (3D) imaging and mapping, like Lidar for remote sensing and navigation, and secure free-space optical communications. The ultimate goal for such a system is to reduce its size, weight, and power consumption, so that it can be mounted on, e.g. drones and autonomous cars. Moreover, beam scanning should ideally be done at video frame rates, something that is beyond the capabilities of current opto-mechanical systems. Photonic integrated circuit (PIC) technology holds the promise of achieving low-cost, compact, robust and energy-efficient complex optical systems. PICs integrate, for example, lasers, modulators, detectors, and filters on a single piece of semiconductor, typically silicon or indium phosphide, much like electronic integrated circuits. This technology is maturing fast, driven by high-bandwidth communications applications, and mature fabrication facilities. State-of-the-art commercial PICs integrate hundreds of elements, and the integration of thousands of elements has been shown in the laboratory. Over the last few years, there has been a considerable research effort to integrate beam steering systems on a PIC, and various beam steering demonstrators based on optical phased arrays have been realized. Arrays of up to thousands of coherent emitters, including their phase and amplitude control, have been integrated, and various applications have been explored. In this review paper, I will present an overview of the state of the art of this technology and its opportunities, illustrated by recent breakthroughs.

Random-access optical-resolution photoacoustic microscopy using a digital micromirror device

PubMed Central

Liang, Jinyang; Zhou, Yong; Winkler, Amy W.; Wang, Lidai; Maslov, Konstantin I.; Li, Chiye; Wang, Lihong V.

2013-01-01

We developed random-access optical-resolution photoacoustic microscopy using a digital micromirror device. This system can rapidly scan arbitrarily shaped regions of interest within a 40×40 μm2 imaging area with a lateral resolution of 3.6 μm. To identify a region of interest, a global structural image is first acquired, then the selected region is scanned. The random-access ability was demonstrated by imaging two static samples, a carbon fiber cross and a monolayer of red blood cells, with an acquisition rate up to 4 kilohertz. The system was then used to monitor blood flow in vivo in real time within user-selected capillaries in a mouse ear. By imaging only the capillary of interest, the frame rate was increased by up to 9.2 times. PMID:23903111

Random-access optical-resolution photoacoustic microscopy using a digital micromirror device.

PubMed

Liang, Jinyang; Zhou, Yong; Winkler, Amy W; Wang, Lidai; Maslov, Konstantin I; Li, Chiye; Wang, Lihong V

2013-08-01

We developed random-access optical-resolution photoacoustic microscopy using a digital micromirror device. This system can rapidly scan arbitrarily shaped regions of interest within a 40 μm×40 μm imaging area with a lateral resolution of 3.6 μm. To identify a region of interest, a global structural image is first acquired, then the selected region is scanned. The random-access ability was demonstrated by imaging two static samples, a carbon fiber cross and a monolayer of red blood cells, with an acquisition rate up to 4 kHz. The system was then used to monitor blood flow in vivo in real time within user-selected capillaries in a mouse ear. By imaging only the capillary of interest, the frame rate was increased by up to 9.2 times.

In vivo imaging of human labial glands using advanced optical coherence tomography.

PubMed

Ozawa, Nobuyoshi; Sumi, Yasunori; Shimozato, Kazuo; Chong, Changho; Kurabayashi, Tohru

2009-09-01

Optical coherence tomography (OCT) has emerged as a high-resolution noninvasive clinical imaging application. The purpose of this study was to show OCT images of human labial glands obtained using a swept-source (SS) OCT system. Labial gland OCT imaging was carried out using our new SS-OCT system for 5 healthy volunteers using a hand-held in vivo OCT scanning probe. The labial tissue was scanned in a superior to inferior direction in 2 and 3 dimensions. The resulting 2- and 3-dimensional ultrahigh-resolution images of in vivo OCT human labial minor salivary glands revealed the epithelium, connective tissue, lobes, and duct. OCT was capable of providing simultaneous and noninvasive structural information with high resolution. This clinical imaging modality promises to have clinical impact in the diagnosis of such conditions as Sjögren syndrome and xerostomia.

Fluorescent scanning laser ophthalmoscopy for cellular resolution in vivo mouse retinal imaging: benefits and drawbacks of implementing adaptive optics (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zhang, Pengfei; Goswami, Mayank; Pugh, Edward N.; Zawadzki, Robert J.

2016-03-01

Scanning Laser Ophthalmoscopy (SLO) is a very important imaging tool in ophthalmology research. By combing with Adaptive Optics (AO) technique, AO-SLO can correct for ocular aberrations resulting in cellular level resolution, allowing longitudinal studies of single cells morphology in the living eyes. The numerical aperture (NA) sets the optical resolution that can be achieve in the "classical" imaging systems. Mouse eye has more than twice NA of the human eye, thus offering theoretically higher resolution. However, in most SLO based imaging systems the imaging beam size at mouse pupil sets the NA of that instrument, while most of the AO-SLO systems use almost the full NA of the mouse eye. In this report, we first simulated the theoretical resolution that can be achieved in vivo for different imaging beam sizes (different NA), assumingtwo cases: no aberrations and aberrations based on published mouse ocular wavefront data. Then we imaged mouse retinas with our custom build SLO system using different beam sizes to compare these results with theory. Further experiments include comparison of the SLO and AO-SLO systems for imaging different type of fluorescently labeled cells (microglia, ganglion, photoreceptors, etc.). By comparing those results and taking into account systems complexity and ease of use, the benefits and drawbacks of two imaging systems will be discussed.

High-speed optical coherence tomography using fiberoptic acousto-optic phase modulation

NASA Astrophysics Data System (ADS)

Xie, Tuqiang; Wang, Zhenguo; Pan, Yingtian

2003-12-01

We report a new rapid-scanning optical delay device suitable for high-speed optical coherence tomography (OCT) in which an acousto-optic modulator (AOM) is used to independently modulate the Doppler frequency shift of the reference light beam for optical heterodyne detection. Experimental results show that the fluctuation of the measured Doppler frequency shift is less than +/-0.2% over 95% duty cycle of OCT imaging, thus allowing for enhanced signal-to-noise ratio of optical heterodyne detection. The increased Doppler frequency shift by AOM also permits complete envelop demodulation without the compromise of reducing axial resolution; if used with a resonant rapid-scanning optical delay, it will permit high-performance real-time OCT imaging. Potentially, this new rapid-scanning optical delay device will improve the performance of high-speed Doppler OCT techniques.

In vivo imaging of the Drosophila Melanogaster heart using a novel optical coherence tomography microscope

NASA Astrophysics Data System (ADS)

Izatt, Susan D.; Choma, Michael A.; Israel, Steven; Wessells, Robert J.; Bodmer, Rolf; Izatt, Joseph A.

2005-03-01

Real time in vivo optical coherence tomography (OCT) imaging of the adult fruit fly Drosophila melanogaster heart using a newly designed OCT microscope allows accurate assessment of cardiac anatomy and function. D. melanogaster has been used extensively in genetic research for over a century, but in vivo evaluation of the heart has been limited by available imaging technology. The ability to assess phenotypic changes with micrometer-scale resolution noninvasively in genetic models such as D. melanogaster is needed in the advancing fields of developmental biology and genetics. We have developed a dedicated small animal OCT imaging system incorporating a state-of-the-art, real time OCT scanner integrated into a standard stereo zoom microscope which allows for simultaneous OCT and video imaging. System capabilities include A-scan, B-scan, and M-scan imaging as well as automated 3D volumetric acquisition and visualization. Transverse and sagittal B-mode scans of the four chambered D. melanogaster heart have been obtained with the OCT microscope and are consistent with detailed anatomical studies from the literature. Further analysis by M-mode scanning is currently under way to assess cardiac function as a function of age and sex by determination of shortening fraction and ejection fraction. These studies create control cardiac data on the wild type D. melanogaster, allowing subsequent evaluation of phenotypic cardiac changes in this model after regulated genetic mutation.

FPGA-based real-time swept-source OCT systems for B-scan live-streaming or volumetric imaging

NASA Astrophysics Data System (ADS)

Bandi, Vinzenz; Goette, Josef; Jacomet, Marcel; von Niederhäusern, Tim; Bachmann, Adrian H.; Duelk, Marcus

2013-03-01

We have developed a Swept-Source Optical Coherence Tomography (Ss-OCT) system with high-speed, real-time signal processing on a commercially available Data-Acquisition (DAQ) board with a Field-Programmable Gate Array (FPGA). The Ss-OCT system simultaneously acquires OCT and k-clock reference signals at 500MS/s. From the k-clock signal of each A-scan we extract a remap vector for the k-space linearization of the OCT signal. The linear but oversampled interpolation is followed by a 2048-point FFT, additional auxiliary computations, and a data transfer to a host computer for real-time, live-streaming of B-scan or volumetric C-scan OCT visualization. We achieve a 100 kHz A-scan rate by parallelization of our hardware algorithms, which run on standard and affordable, commercially available DAQ boards. Our main development tool for signal analysis as well as for hardware synthesis is MATLAB® with add-on toolboxes and 3rd-party tools.

Optical properties of doped sol-gel silica glasses

NASA Astrophysics Data System (ADS)

King, Terence A.

1994-01-01

Sol-gel optical composites were developed and characterized for potential applications in optics, lasers, nonlinear optics, and optoelectronics. Post-doped xerogels were index matched by in-situ polymerization of monomers to form inorganic-organic composites of low scatter and high optical quality. Characterization of the microstructure was made by visible and IR absorption and Raman Spectroscopy and optical quality by attenuation and scatter measurement. Doping techniques were optimized using hypercritical drying and vacuum impregnation and doping distribution monitored by laser-induced fluorescence. One-tenth wavelength surfaces were formed by novel optical polishing. Organic molecular dopants were tested in laser and nonlinear systems. Initial third harmonic generation and Z-scan measurements have shown the potential for saturable absorption and optical limiting.

A new scanning system for alpha decay events as calibration sources for range-energy relation in nuclear emulsion

NASA Astrophysics Data System (ADS)

Yoshida, J.; Kinbara, S.; Mishina, A.; Nakazawa, K.; Soe, M. K.; Theint, A. M. M.; Tint, K. T.

2017-03-01

A new scanning system named "Vertex picker" has been developed to rapid collect alpha decay events, which are calibration sources for the range-energy relation in nuclear emulsion. A computer-controlled optical microscope scans emulsion layers exhaustively, and a high-speed and high-resolution camera takes their micrographs. A dedicated image processing picks out vertex-like shapes. Practical operations of alpha decay search were demonstrated by emulsion sheets of the KEK-PS E373 experiment. Alpha decays of nearly 28 events were detected in eye-check work on a PC monitor per hour. This yield is nearly 20 times more effective than that by the conventional eye-scan method. The speed and quality is acceptable for the coming new experiment, J-PARC E07.

Three Dimensional Reconstruction Algorithm for Imaging Pathophysiological Signals Within Breast Tissue Using Near Infrared Light

DTIC Science & Technology

2006-07-01

of water, gelatin (G2625, Sigma Inc.), India ink (for absorption), and titanium dioxide powder (for scatter) (TiO2, Sigma Inc.) is poured into a mold...R. C., Ference, R. J, Refractive index of some mammalian tissue using a fiber optic cladding method. Applied Optics, 1989. 28(12): p. 2297-2303. 3...scans. The NIR system utilizes six optical wavelengths from 660 to 850 nm using intensity modulated diode lasers nominally working at 100 MHz

Research and Simulation in Support of Near Real Time/Real Time Reconnaissance RPV Systems

DTIC Science & Technology

1977-06-01

Image 4,5.2 Raster Lines Across Image 4.5.3 Angle Projected by Displayed Image 4.6 Optical Defocusing SIMULATION CONSIDERATIONS PAGE 162 162 162...television and infrared, there are a finite number of resolution elements across the format. As a consequence, selection of a shorter optical focal...light that is scanned across and down the CRT to form a raster similar to that seen in a standard television tube. The light is optically projected

Metal-Coated Optical Fibers for High Temperature Applications

NASA Technical Reports Server (NTRS)

Zeakes, Jason; Murphy, Kent; Claus, Richard; Greene, Jonathan; Tran, Tuan

1996-01-01

A DC magnetron sputtering system has been used to actively coat optical fibers with hermetic metal coatings during the fiber draw process. Thin films of Inconel 625 have been deposited on optical fibers and annealed in air at 2000 F. Scanning electron microscopy and Auger electron microscopy have been used to investigate the morphology and composition of the films prior to and following thermal cycling. Issues to be addressed include film adhesion, other coating materials, and a discussion of additional applications for this novel technology.

Evaluation of acute radiation optic neuropathy by B-scan ultrasonography

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

Lovato, A.A.; Char, D.H.; Quivey, J.M.

1990-09-15

We studied the accuracy of B-scan ultrasonography to diagnose radiation-induced optic neuropathy in 15 patients with uveal melanoma. Optic neuropathy was diagnosed by an observer masked as to clinical and photographic data. We analyzed planimetry area measurements of the retrobulbar nerve before and after irradiation. The retrobulbar area of the optic nerve shadow on B-scan was quantitated with a sonic digitizer. Increased optic nerve shadow area was confirmed in 13 of 15 patients who had radiation optic neuropathy (P less than .004). The correct diagnosis was confirmed when the results of ultrasound were compared to fundus photography and fluorescein angiography.more » In 13 patients there was acute radiation optic neuropathy. Two patients did not show an enlarged retrobulbar optic nerve, and the clinical appearance suggested early progression to optic atrophy. Ultrasonography documents the enlargement of the optic nerve caused by acute radiation changes.« less

Real-time continuous-wave terahertz line scanner based on a compact 1 × 240 InGaAs Schottky barrier diode array detector.

PubMed

Han, Sang-Pil; Ko, Hyunsung; Kim, Namje; Lee, Won-Hui; Moon, Kiwon; Lee, Il-Min; Lee, Eui Su; Lee, Dong Hun; Lee, Wangjoo; Han, Seong-Tae; Choi, Sung-Wook; Park, Kyung Hyun

2014-11-17

We demonstrate real-time continuous-wave terahertz (THz) line-scanned imaging based on a 1 × 240 InGaAs Schottky barrier diode (SBD) array detector with a scan velocity of 25 cm/s, a scan line length of 12 cm, and a pixel size of 0.5 × 0.5 mm². Foreign substances, such as a paper clip with a spatial resolution of approximately 1 mm that is hidden under a cracker, are clearly detected by this THz line-scanning system. The system consists of the SBD array detector, a 200-GHz gyrotron source, a conveyor system, and several optical components such as a high-density polyethylene cylindrical lens, metal cylindrical mirror, and THz wire-grid polarizer. Using the THz polarizer, the signal-to-noise ratio of the SBD array detector improves because the quality of the source beam is enhanced.

A wide field-of-view microscope based on holographic focus grid

NASA Astrophysics Data System (ADS)

Wu, Jigang; Cui, Xiquan; Zheng, Guoan; Lee, Lap Man; Yang, Changhuei

2010-02-01

We have developed a novel microscope technique that can achieve wide field-of-view (FOV) imaging and yet possess resolution that is comparable to conventional microscope. The principle of wide FOV microscope system breaks the link between resolution and FOV magnitude of traditional microscopes. Furthermore, by eliminating bulky optical elements from its design and utilizing holographic optical elements, the wide FOV microscope system is more cost-effective. In our system, a hologram was made to focus incoming collimated beam into a focus grid. The sample is put in the focal plane and the transmissions of the focuses are detected by an imaging sensor. By scanning the incident angle of the incoming beam, the focus grid will scan across the sample and the time-varying transmission can be detected. We can then reconstruct the transmission image of the sample. The resolution of microscopic image is limited by the size of the focus formed by the hologram. The scanning area of each focus spot is determined by the separation of the focus spots and can be made small for fast imaging speed. We have fabricated a prototype system with a 2.4-mm FOV and 1-μm resolution. The prototype system was used to image onion skin cells for a demonstration. The preliminary experiments prove the feasibility of the wide FOV microscope technique, and the possibility of a wider FOV system with better resolution.

Quantification of root caries using optical coherence tomography and microradiography: a correlational study.

PubMed

Amaechi, Bennett T; Podoleanu, Adrian Gh; Komarov, Gleb; Higham, Susan M; Jackson, David A

2004-01-01

The use of transverse microradiography (TMR) to quantify the amount of mineral lost during demineralization of tooth tissue has long been established. In the present study, the use of an en-face Optical Coherence Tomography (OCT) technology to detect and quantitatively monitor the mineral changes in root caries was investigated and correlated with TMR. We used an OCT system, developed initially for retina imaging, and which can collect A-scans, B-scans (longitudinal images) and C-scans (en-face images) to quantitatively assess the development of root caries. The power to the sample was 250 microW, wavelength lambda = 850 nm and the optical source linewidth was 16 microm. Both the transversal and longitudinal images showed the caries lesion as volumes of reduced reflectivity. Quantitative analysis using the A-scan (reflectivity versus depth curve) showed that the tissue reflectivity decreased with increasing demineralization time. A linear correlation (r = 0.957) was observed between the mineral loss measured by TMR and the percentage reflectivity loss in demineralized tissue measured by OCT. We concluded that OCT could be used to detect incipient root caries, and that the reflectivity loss in root tissue during demineralization, measured by OCT, could be related to the amount of mineral lost during the demineralization.

Phase and amplitude beam shaping with two deformable mirrors implementing input plane and Fourier plane phase modifications.

PubMed

Wu, Chensheng; Ko, Jonathan; Rzasa, John R; Paulson, Daniel A; Davis, Christopher C

2018-03-20

We find that ideas in optical image encryption can be very useful for adaptive optics in achieving simultaneous phase and amplitude shaping of a laser beam. An adaptive optics system with simultaneous phase and amplitude shaping ability is very desirable for atmospheric turbulence compensation. Atmospheric turbulence-induced beam distortions can jeopardize the effectiveness of optical power delivery for directed-energy systems and optical information delivery for free-space optical communication systems. In this paper, a prototype adaptive optics system is proposed based on a famous image encryption structure. The major change is to replace the two random phase plates at the input plane and Fourier plane of the encryption system, respectively, with two deformable mirrors that perform on-demand phase modulations. A Gaussian beam is used as an input to replace the conventional image input. We show through theory, simulation, and experiments that the slightly modified image encryption system can be used to achieve arbitrary phase and amplitude beam shaping within the limits of stroke range and influence function of the deformable mirrors. In application, the proposed technique can be used to perform mode conversion between optical beams, generate structured light signals for imaging and scanning, and compensate atmospheric turbulence-induced phase and amplitude beam distortions.

Phased array-fed antenna configuration study: Technology assessment

NASA Technical Reports Server (NTRS)

Croswell, W. F.; Ball, D. E.; Taylor, R. C.

1983-01-01

Spacecraft array fed reflector antenna systems were assessed for particular application to a multiple fixed spot beam/multiple scanning spot beam system. Reflector optics systems are reviewed in addition to an investigation of the feasibility of the use of monolithic microwave integrated circuit power amplifiers and phase shifters in each element of the array feed.

Tip-enhanced near-field Raman spectroscopy with a scanning tunneling microscope and side-illumination optics.

PubMed

Yi, K J; He, X N; Zhou, Y S; Xiong, W; Lu, Y F

2008-07-01

Conventional Raman spectroscopy (RS) suffers from low spatial resolution and low detection sensitivity due to the optical diffraction limit and small interaction cross sections. It has been reported that a highly localized and significantly enhanced electromagnetic field could be generated in the proximity of a metallic tip illuminated by a laser beam. In this study, a tip-enhanced RS system was developed to both improve the resolution and enhance the detection sensitivity using the tip-enhanced near-field effects. This instrument, by combining RS with a scanning tunneling microscope and side-illumination optics, demonstrated significant enhancement on both optical sensitivity and spatial resolution using either silver (Ag)-coated tungsten (W) tips or gold (Au) tips. The sensitivity improvement was verified by observing the enhancement effects on silicon (Si) substrates. Lateral resolution was verified to be below 100 nm by mapping Ag nanostructures. By deploying the depolarization technique, an apparent enhancement of 175% on Si substrates was achieved. Furthermore, the developed instrument features fast and reliable optical alignment, versatile sample adaptability, and effective suppression of far-field signals.

In-vivo, real-time cross-sectional images of retina using a GPU enhanced master slave optical coherence tomography system

NASA Astrophysics Data System (ADS)

Bradu, Adrian; Kapinchev, Konstantin; Barnes, Frederick; Podoleanu, Adrian

2016-03-01

In our previous reports we demonstrated a novel Fourier domain optical coherence tomography method, Master Slave optical coherence tomography (MS-OCT), that does not require resampling of data and can deliver en-face images from several depths simultaneously. While ideally suited for delivering information from a selected depth, the MS-OCT has been so far inferior to the conventional FFT based OCT in terms of time of producing cross section images. Here, we demonstrate that by taking advantage of the parallel processing capabilities offered by the MS-OCT method, cross-sectional OCT images of the human retina can be produced in real-time by assembling several T-scans from different depths. We analyze the conditions that ensure a real-time B-scan imaging operation, and demonstrate in-vivo real-time images from human fovea and the optic nerve, of comparable resolution and sensitivity to those produced using the traditional Fourier domain based method.

Visual imaging control systems of the Mariner to Jupiter and Saturn spacecraft

NASA Technical Reports Server (NTRS)

Larks, L.

1979-01-01

Design and fabrication of optical systems for the Mariner Jupiter Saturn (Voyager) mission is described. Because of the long distances of these planets from the sun, the spacecraft was designed without solar panels with the electricity generated on-board by radio-isotope thermal generators (RTG). The presence of RTG's and Jupiter radiation environment required that the optical systems be fabricated out of radiation stabilized materials. A narrow angle and a wide angle camera are located on the spacecraft scan platform, with the narrow angle lens a modification of the Mariner 10 lens. The optical system is described, noting that the lens was modified by moving the aperture correctors forward and placing a spider mounted secondary mirror in the original back surface of the second aperture corrector. The wide angle lens was made out of cerium doped, radiation stabilized optical glass with greatest blue transmittance, which would be resistant to RTG and Jupiter radiation.

Characterization of a Hybrid Optical Microscopy/Laser Ablation Liquid Vortex Capture/Electrospray Ionization System for Mass Spectrometry Imaging

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

Cahill, John F.; Kertesz, Vilmos; Van Berkel, Gary J.

Herein, a commercial optical microscope, laser microdissection instrument was coupled with an electrospray ionization mass spectrometer via a low profile liquid vortex capture probe to yield a hybrid optical microscopy/mass spectrometry imaging system. The instrument has bright-field and fluorescence microscopy capabilities in addition to a highly focused UV laser beam that is utilized for laser ablation of samples. With this system, material laser ablated from a sample using the microscope was caught by a liquid vortex capture probe and transported in solution for analysis by electrospray ionization mass spectrometry. Both lane scanning and spot sampling mass spectral imaging modes weremore » used. The smallest area the system was able to ablate was ~0.544 μm × ~0.544 μm, achieved by oversampling of the smallest laser ablation spot size that could be obtained (~1.9 μm). With use of a model photoresist surface, known features as small as ~1.5 μm were resolved. The capabilities of the system with real world samples were demonstrated first with a blended polymer thin film containing poly(2-vinylpyridine) and poly(N-vinylcarbazole). Using spot sampling imaging, sub-micrometer sized features (0.62, 0.86, and 0.98 μm) visible by optical microscopy were clearly distinguished in the mass spectral images. A second real world example showed the imaging of trace amounts of cocaine in mouse brain thin tissue sections. Lastly, with use of a lane scanning mode with ~6 μm × ~6 μm data pixels, features in the tissue as small as 15 μm in size could be distinguished in both the mass spectral and optical images.« less

Characterization of a Hybrid Optical Microscopy/Laser Ablation Liquid Vortex Capture/Electrospray Ionization System for Mass Spectrometry Imaging

DOE PAGES

Cahill, John F.; Kertesz, Vilmos; Van Berkel, Gary J.

2015-10-22

Herein, a commercial optical microscope, laser microdissection instrument was coupled with an electrospray ionization mass spectrometer via a low profile liquid vortex capture probe to yield a hybrid optical microscopy/mass spectrometry imaging system. The instrument has bright-field and fluorescence microscopy capabilities in addition to a highly focused UV laser beam that is utilized for laser ablation of samples. With this system, material laser ablated from a sample using the microscope was caught by a liquid vortex capture probe and transported in solution for analysis by electrospray ionization mass spectrometry. Both lane scanning and spot sampling mass spectral imaging modes weremore » used. The smallest area the system was able to ablate was ~0.544 μm × ~0.544 μm, achieved by oversampling of the smallest laser ablation spot size that could be obtained (~1.9 μm). With use of a model photoresist surface, known features as small as ~1.5 μm were resolved. The capabilities of the system with real world samples were demonstrated first with a blended polymer thin film containing poly(2-vinylpyridine) and poly(N-vinylcarbazole). Using spot sampling imaging, sub-micrometer sized features (0.62, 0.86, and 0.98 μm) visible by optical microscopy were clearly distinguished in the mass spectral images. A second real world example showed the imaging of trace amounts of cocaine in mouse brain thin tissue sections. Lastly, with use of a lane scanning mode with ~6 μm × ~6 μm data pixels, features in the tissue as small as 15 μm in size could be distinguished in both the mass spectral and optical images.« less

Space-multiplexed optical scanner.

PubMed

Riza, Nabeel A; Yaqoob, Zahid

2004-05-01

A low-loss two-dimensional optical beam scanner that is capable of delivering large (e.g., > 10 degrees) angular scans along the elevation as well as the azimuthal direction is presented. The proposed scanner is based on a space-switched parallel-serial architecture that employs a coarse-scanner module and a fine-scanner module that produce an ultrahigh scan space-fill factor, e.g., 900 x 900 distinguishable beams in a 10 degrees (elevation) x 10 degrees (azimuth) scan space. The experimentally demonstrated one-dimensional version of the proposed scanner has a supercontinuous scan, 100 distinguishable beam spots in a 2.29 degrees total scan range, and 1.5-dB optical insertion loss.

Optimizing pulse compressibility in completely all-fibered Ytterbium chirped pulse amplifiers for in vivo two photon laser scanning microscopy

PubMed Central

Fernández, A.; Grüner-Nielsen, L.; Andreana, M.; Stadler, M.; Kirchberger, S.; Sturtzel, C.; Distel, M.; Zhu, L.; Kautek, W.; Leitgeb, R.; Baltuska, A.; Jespersen, K.; Verhoef, A.

2017-01-01

A simple and completely all-fiber Yb chirped pulse amplifier that uses a dispersion matched fiber stretcher and a spliced-on hollow core photonic bandgap fiber compressor is applied in nonlinear optical microscopy. This stretching-compression approach improves compressibility and helps to maximize the fluorescence signal in two-photon laser scanning microscopy as compared with approaches that use standard single mode fibers as stretcher. We also show that in femtosecond all-fiber systems, compensation of higher order dispersion terms is relevant even for pulses with relatively narrow bandwidths for applications relying on nonlinear optical effects. The completely all-fiber system was applied to image green fluorescent beads, a stained lily-of-the-valley root and rat-tail tendon. We also demonstrated in vivo imaging in zebrafish larvae, where we simultaneously measure second harmonic and fluorescence from two-photon excited red-fluorescent protein. Since the pulses are compressed in a fiber, this source is especially suited for upgrading existing laser scanning (confocal) microscopes with multiphoton imaging capabilities in space restricted settings or for incorporation in endoscope-based microscopy. PMID:28856032

Optimizing pulse compressibility in completely all-fibered Ytterbium chirped pulse amplifiers for in vivo two photon laser scanning microscopy.

PubMed

Fernández, A; Grüner-Nielsen, L; Andreana, M; Stadler, M; Kirchberger, S; Sturtzel, C; Distel, M; Zhu, L; Kautek, W; Leitgeb, R; Baltuska, A; Jespersen, K; Verhoef, A

2017-08-01

A simple and completely all-fiber Yb chirped pulse amplifier that uses a dispersion matched fiber stretcher and a spliced-on hollow core photonic bandgap fiber compressor is applied in nonlinear optical microscopy. This stretching-compression approach improves compressibility and helps to maximize the fluorescence signal in two-photon laser scanning microscopy as compared with approaches that use standard single mode fibers as stretcher. We also show that in femtosecond all-fiber systems, compensation of higher order dispersion terms is relevant even for pulses with relatively narrow bandwidths for applications relying on nonlinear optical effects. The completely all-fiber system was applied to image green fluorescent beads, a stained lily-of-the-valley root and rat-tail tendon. We also demonstrated in vivo imaging in zebrafish larvae, where we simultaneously measure second harmonic and fluorescence from two-photon excited red-fluorescent protein. Since the pulses are compressed in a fiber, this source is especially suited for upgrading existing laser scanning (confocal) microscopes with multiphoton imaging capabilities in space restricted settings or for incorporation in endoscope-based microscopy.

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.

MEMS micromirrors for optical switching in multichannel spectrophotometers

NASA Astrophysics Data System (ADS)

Tuantranont, Adisorn; Lomas, Tanom; Bright, Victor M.

2004-04-01

This paper reports for the first time that a novel MEMS-based micromirror switch has successfully demonstrated for optical switching in a multi-channel fiber optics spectrophotometer system. The conventional optomechanical fiber optic switches for multi-channel spectrophotometers available in market are bulky, slow, low numbers of channels and expensive. Our foundry MEMS-based micromirror switch designed for integrating with commercially available spectrophotometers offers more compact devices, increased number of probing channels, higher performance and cheaper. Our MEMS-based micromirror switch is a surface micromachined mirror fabricated through MUMPs foundry. The 280 μm x 280 μm gold coated mirror is suspended by the double-gimbal structure for X and Y axis scanning. Self-assembly by solders is used to elevate the torsion mirror 30 μm over the substrate to achieve large scan angle. The solder self-assembly approach dramatically reduces the time to assembly the switch. The scan mirror is electrostatically controlled by applying voltages. The individual probing signal from each probing head is guided by fibers with collimated lenses and incidents on the center of the mirror. The operating scan angle is in the range of 3.5 degrees with driving voltage of 0-100 V. The fastest switching time of 4 millisecond (1 ms rise time and 3 ms fall time) is measured corresponding to the maximum speed of the mirror of 0.25 kHz when the mirror is scanning at +/- 1.5 degrees. The micromirror switch is packaged with a multi-mode fiber bundle using active alignment technique. A centered fiber is the output fiber that is connected to spectrophotometer. Maximum insertion loss of 5 dB has been obtained. The accuracy of measured spectral data is equivalent to the single channel spectrophotometer with a small degradation on probing signal due to fiber coupling.

Noninvasive structural and microvascular anatomy of oral mucosae using handheld optical coherence tomography

PubMed Central

Tsai, Meng-Tsan; Chen, Yingdan; Lee, Cheng-Yu; Huang, Bo-Huei; Trung, Nguyen Hoang; Lee, Ya-Ju; Wang, Yen-Li

2017-01-01

In this study, we demonstrated the feasibility of using a handheld optical coherence tomography (OCT) for in vivo visualizations of the microstructural and microvascular features of various oral mucosal types. To scan arbitrary locations of the oral mucosa, a scanning probe was developed, composed of a probe body fabricated by a 3D printer, miniaturized two-axis galvanometer, relay lenses, and reflective prism. With a 3D printing technique, the probe weight and the system volume were greatly reduced, enabling the effective improvement of imaging artifacts from unconscious motion and system complexity. Additionally, in our design, the distal end of the probe can be switched to fit various oral conditions, and the optical parameters of the probe, such as the transverse resolution, working distance, and probe length can be easily varied. The results showed that the epithelium and lamina propria layers, as well as the fungiform papilla and salivary gland, were differentiated. Moreover, various microcirculation features at different mucosal sites were identified that are potentially effective indicators for the diagnosis of premalignant lesions. The demonstrated results indicate that the developed OCT system is a promising tool for noninvasive imaging of oral mucosae. PMID:29188097

Motion-compensated hand-held common-path Fourier-domain optical coherence tomography probe for image-guided intervention

NASA Astrophysics Data System (ADS)

Huang, Yong; Song, Cheol; Liu, Xuan; Kang, Jin U.

2013-03-01

A motion-compensated hand-held common-path Fourier-domain optical coherence tomography imaging probe has been developed for image guided intervention during microsurgery. A hand-held prototype instrument was designed and fabricated by integrating an imaging fiber probe inside a stainless steel needle which is attached to the ceramic shaft of a piezoelectric motor housed in an aluminum handle. The fiber probe obtains A-scan images. The distance information was extracted from the A-scans to track the sample surface distance and a fixed distance was maintained by a feedback motor control which effectively compensated hand tremor and target movements in the axial direction. Graphical user interface, real-time data processing, and visualization based on a CPU-GPU hybrid programming architecture were developed and used in the implantation of this system. To validate the system, free-hand optical coherence tomography images using various samples were obtained. The system can be easily integrated into microsurgical tools and robotics for a wide range of clinical applications. Such tools could offer physicians the freedom to easily image sites of interest with reduced risk and higher image quality.

Scanning properties of large dual-shaped offset and symmetric reflector antennas

NASA Astrophysics Data System (ADS)

Galindo-Israel, Victor; Veruttipong, Watt; Norrod, Roger D.; Imbriale, William A.

1992-04-01

Several characteristics of dual offset (DOSR) and symmetric shaped reflectors are examined. Among these is the amelioration of the added cost of manufacturing a shaped reflector antenna, particularly a doubly curved surface for the DOSR, if adjustable panels, which may be necessary for correction of gravity and wind distortions, are also used for improving gain by shaping. The scanning properties of shaped reflectors, both offset and circularly symmetric, are examined and compared to conic section scanning characteristics. Scanning of the pencil beam is obtained by lateral and axial translation of a single point-source feed. The feed is kept pointed toward the center of the subreflector. The effects of power spillover and aperture phase error as a function of beam scanning is examined for several different types of large reflector designs including DOSR, circularly symmetric large f/D and smaller f/D dual reflector antenna systems. It is graphically illustrated that the Abbe-sine condition for improving scanning of an optical system cannot, inherently, be satisfied in a dual-shaped reflector system shaped for high gain and low feed spillover.

Usability of a real-time tracked augmented reality display system in musculoskeletal injections

NASA Astrophysics Data System (ADS)

Baum, Zachary; Ungi, Tamas; Lasso, Andras; Fichtinger, Gabor

2017-03-01

PURPOSE: Image-guided needle interventions are seldom performed with augmented reality guidance in clinical practice due to many workspace and usability restrictions. We propose a real-time optically tracked image overlay system to make image-guided musculoskeletal injections more efficient and assess its usability in a bed-side clinical environment. METHODS: An image overlay system consisting of an optically tracked viewbox, tablet computer, and semitransparent mirror allows users to navigate scanned patient volumetric images in real-time using software built on the open-source 3D Slicer application platform. A series of experiments were conducted to evaluate the latency and screen refresh rate of the system using different image resolutions. To assess the usability of the system and software, five medical professionals were asked to navigate patient images while using the overlay and completed a questionnaire to assess the system. RESULTS: In assessing the latency of the system with scanned images of varying size, screen refresh rates were approximately 5 FPS. The study showed that participants found using the image overlay system easy, and found the table-mounted system was significantly more usable and effective than the handheld system. CONCLUSION: It was determined that the system performs comparably with scanned images of varying size when assessing the latency of the system. During our usability study, participants preferred the table-mounted system over the handheld. The participants also felt that the system itself was simple to use and understand. With these results, the image overlay system shows promise for use in a clinical environment.

Analysis of the Origin of Atypical Scanning Laser Polarimetry Patterns by Polarization-Sensitive Optical Coherence Tomography

PubMed Central

Götzinger, Erich; Pircher, Michael; Baumann, Bernhard; Hirn, Cornelia; Vass, Clemens; Hitzenberger, Christoph K.

2010-01-01

Purpose To analyze the physical origin of atypical scanning laser polarimetry (SLP) patterns. To compare polarization-sensitive optical coherence tomography (PS-OCT) scans to SLP images. To present a method to obtain pseudo-SLP images by PS-OCT that are free of atypical artifacts. Methods Forty-one eyes of healthy subjects, subjects with suspected glaucoma, and patients with glaucoma were imaged by SLP (GDx VCC) and a prototype spectral domain PS-OCT system. The PS-OCT system acquires three-dimensional (3D) datasets of intensity, retardation, and optic axis orientation simultaneously within 3 seconds. B-scans of intensity and retardation and en face maps of retinal nerve fiber layer (RNFL) retardation were derived from the 3D PS-OCT datasets. Results were compared with those obtained by SLP. Results Twenty-two eyes showed atypical retardation patterns, and 19 eyes showed normal patterns. From the 22 atypical eyes, 15 showed atypical patterns in both imaging modalities, five were atypical only in SLP images, and two were atypical only in PS-OCT images. In most (15 of 22) atypical cases, an increased penetration of the probing beam into the birefringent sclera was identified as the source of atypical patterns. In such cases, the artifacts could be eliminated in PS-OCT images by depth segmentation and exclusion of scleral signals. Conclusions PS-OCT provides deeper insight into the contribution of different fundus layers to SLP images. Increased light penetration into the sclera can distort SLP retardation patterns of the RNFL. PMID:19036999

Dynamic phase-sensitive optical coherence elastography at a true kilohertz frame-rate

NASA Astrophysics Data System (ADS)

Singh, Manmohan; Wu, Chen; Liu, Chih-Hao; Li, Jiasong; Schill, Alexander; Nair, Achuth; Larin, Kirill V.

2016-03-01

Dynamic optical coherence elastography (OCE) techniques have rapidly emerged as a noninvasive way to characterize the biomechanical properties of tissue. However, clinical applications of the majority of these techniques have been unfeasible due to the extended acquisition time because of multiple temporal OCT acquisitions (M-B mode). Moreover, multiple excitations, large datasets, and prolonged laser exposure prohibit their translation to the clinic, where patient discomfort and safety are critical criteria. Here, we demonstrate the feasibility of noncontact true kilohertz frame-rate dynamic optical coherence elastography by directly imaging a focused air-pulse induced elastic wave with a home-built phase-sensitive OCE system. The OCE system was based on a 4X buffered Fourier Domain Mode Locked swept source laser with an A-scan rate of ~1.5 MHz, and imaged the elastic wave propagation at a frame rate of ~7.3 kHz. Because the elastic wave directly imaged, only a single excitation was utilized for one line scan measurement. Rather than acquiring multiple temporal scans at successive spatial locations as with previous techniques, here, successive B-scans were acquired over the measurement region (B-M mode). Preliminary measurements were taken on tissue-mimicking agar phantoms of various concentrations, and the results showed good agreement with uniaxial mechanical compression testing. Then, the elasticity of an in situ porcine cornea in the whole eye-globe configuration at various intraocular pressures was measured. The results showed that this technique can acquire a depth-resolved elastogram in milliseconds. Furthermore, the ultra-fast acquisition ensured that the laser safety exposure limit for the cornea was not exceeded.

Closed-loop optical stabilization and digital image registration in adaptive optics scanning light ophthalmoscopy

PubMed Central

Yang, Qiang; Zhang, Jie; Nozato, Koji; Saito, Kenichi; Williams, David R.; Roorda, Austin; Rossi, Ethan A.

2014-01-01

Eye motion is a major impediment to the efficient acquisition of high resolution retinal images with the adaptive optics (AO) scanning light ophthalmoscope (AOSLO). Here we demonstrate a solution to this problem by implementing both optical stabilization and digital image registration in an AOSLO. We replaced the slow scanning mirror with a two-axis tip/tilt mirror for the dual functions of slow scanning and optical stabilization. Closed-loop optical stabilization reduced the amplitude of eye-movement related-image motion by a factor of 10–15. The residual RMS error after optical stabilization alone was on the order of the size of foveal cones: ~1.66–2.56 μm or ~0.34–0.53 arcmin with typical fixational eye motion for normal observers. The full implementation, with real-time digital image registration, corrected the residual eye motion after optical stabilization with an accuracy of ~0.20–0.25 μm or ~0.04–0.05 arcmin RMS, which to our knowledge is more accurate than any method previously reported. PMID:25401030

The optical design of a far infrared imaging FTS for SPICA

NASA Astrophysics Data System (ADS)

Pastor, Carmen; Zuluaga, Pablo; Jellema, Willem; González Fernández, Luis Miguel; Belenguer, Tomas; Torres Redondo, Josefina; Kooijman, Peter Paul; Najarro, Francisco; Eggens, Martin; Roelfsema, Peter; Nakagawa, Takao

2014-08-01

This paper describes the optical design of the far infrared imaging spectrometer for the JAXA's SPICA mission. The SAFARI instrument, is a cryogenic imaging Fourier transform spectrometer (iFTS), designed to perform backgroundlimited spectroscopic and photometric imaging in the band 34-210 μm. The all-reflective optical system is highly modular and consists of three main modules; input optics module, interferometer module (FTS) and camera bay optics. A special study has been dedicated to the spectroscopic performance of the instrument, in which the spectral response and interference of the instrument have been modeled, as the FTS mechanism scans over the total desired OPD range.

Fiber-optic fluorescence imaging

PubMed Central

Flusberg, Benjamin A; Cocker, Eric D; Piyawattanametha, Wibool; Jung, Juergen C; Cheung, Eunice L M; Schnitzer, Mark J

2010-01-01

Optical fibers guide light between separate locations and enable new types of fluorescence imaging. Fiber-optic fluorescence imaging systems include portable handheld microscopes, flexible endoscopes well suited for imaging within hollow tissue cavities and microendoscopes that allow minimally invasive high-resolution imaging deep within tissue. A challenge in the creation of such devices is the design and integration of miniaturized optical and mechanical components. Until recently, fiber-based fluorescence imaging was mainly limited to epifluorescence and scanning confocal modalities. Two new classes of photonic crystal fiber facilitate ultrashort pulse delivery for fiber-optic two-photon fluorescence imaging. An upcoming generation of fluorescence imaging devices will be based on microfabricated device components. PMID:16299479

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.

Molecular imaging using light-absorbing imaging agents and a clinical optical breast imaging system--a phantom study.

PubMed

van de Ven, Stephanie M W Y; Mincu, Niculae; Brunette, Jean; Ma, Guobin; Khayat, Mario; Ikeda, Debra M; Gambhir, Sanjiv S

2011-04-01

The aim of the study was to determine the feasibility of using a clinical optical breast scanner with molecular imaging strategies based on modulating light transmission. Different concentrations of single-walled carbon nanotubes (SWNT; 0.8-20.0 nM) and black hole quencher-3 (BHQ-3; 2.0-32.0 µM) were studied in specifically designed phantoms (200-1,570 mm(3)) with a clinical optical breast scanner using four wavelengths. Each phantom was placed in the scanner tank filled with optical matching medium. Background scans were compared to absorption scans, and reproducibility was assessed. All SWNT phantoms were detected at four wavelengths, with best results at 684 nm. Higher concentrations (≥8.0 µM) were needed for BHQ-3 detection, with the largest contrast at 684 nm. The optical absorption signal was dependent on phantom size and concentration. Reproducibility was excellent (intraclass correlation 0.93-0.98). Nanomolar concentrations of SWNT and micromolar concentrations of BHQ-3 in phantoms were reproducibly detected, showing the potential of light absorbers, with appropriate targeting ligands, as molecular imaging agents for clinical optical breast imaging.

Joint Services Electronics Program Annual Progress Report.

DTIC Science & Technology

1987-10-15

polarizability of free carriers in the semiconductor perturb the index of refraction which can be detected in a Nomarski -type optical interferometer. For...interferomters. However, the charge probe relies on a different physical effect and operates by interferometrically detecting the phase change induced in an... Nomarski microscope systems. These techniques will be applied, eventually, in our real-time V.. scanning optical microscope described below. Recently

Toward Optical Sensors: Review and Applications

NASA Astrophysics Data System (ADS)

Sabri, Naseer; Aljunid, S. A.; Salim, M. S.; Ahmad, R. B.; Kamaruddin, R.

2013-04-01

Recent advances in fiber optics (FOs) and the numerous advantages of light over electronic systems have boosted the utility and demand for optical sensors in various military, industry and social fields. Environmental and atmospheric monitoring, earth and space sciences, industrial chemical processing and biotechnology, law enforcement, digital imaging, scanning, and printing are exemplars of them. The ubiquity of photonic technologies could drive down prices which reduced the cost of optical fibers and lasers. Fiber optic sensors (FOSs) offer a wide spectrum of advantages over traditional sensing systems, such as small size and longer lifetime. Immunity to electromagnetic interference, amenability to multiplexing, and high sensitivity make FOs the sensor technology of choice in several fields, including the healthcare and aerospace sectors. FOSs show reliable and rigid sensing tasks over conventional electrical and electronic sensors. This paper presents an executive review of optical fiber sensors and the most beneficial applications.

High-speed spectral domain polarization- sensitive optical coherence tomography using a single camera and an optical switch at 1.3 microm.

PubMed

Lee, Sang-Won; Jeong, Hyun-Woo; Kim, Beop-Min

2010-01-01

We propose high-speed spectral domain polarization-sensitive optical coherence tomography (SD-PS-OCT) using a single camera and a 1x2 optical switch at the 1.3-microm region. The PS-low coherence interferometer used in the system is constructed using free-space optics. The reflected horizontal and vertical polarization light rays are delivered via an optical switch to a single spectrometer by turns. Therefore, our system costs less to build than those that use dual spectrometers, and the processes of timing and triggering are simpler from the viewpoints of both hardware and software. Our SD-PS-OCT has a sensitivity of 101.5 dB, an axial resolution of 8.2 microm, and an acquisition speed of 23,496 A-scans per second. We obtain the intensity, phase retardation, and fast axis orientation images of a rat tail tendon ex vivo.

Processing of fetal heart rate through non-invasive adaptive system based on recursive least squares algorithm

NASA Astrophysics Data System (ADS)

Fajkus, Marcel; Nedoma, Jan; Martinek, Radek; Vasinek, Vladimir

2017-10-01

In this article, we describe an innovative non-invasive method of Fetal Phonocardiography (fPCG) using fiber-optic sensors and adaptive algorithm for the measurement of fetal heart rate (fHR). Conventional PCG is based on a noninvasive scanning of acoustic signals by means of a microphone placed on the thorax. As for fPCG, the microphone is placed on the maternal abdomen. Our solution is based on patent pending non-invasive scanning of acoustic signals by means of a fiber-optic interferometer. Fiber-optic sensors are resistant to technical artifacts such as electromagnetic interferences (EMI), thus they can be used in situations where it is impossible to use conventional EFM methods, e.g. during Magnetic Resonance Imaging (MRI) examination or in case of delivery in water. The adaptive evaluation system is based on Recursive least squares (RLS) algorithm. Based on real measurements provided on five volunteers with their written consent, we created a simplified dynamic signal model of a distribution of heartbeat sounds (HS) through the human body. Our created model allows us to verification of the proposed adaptive system RLS algorithm. The functionality of the proposed non-invasive adaptive system was verified by objective parameters such as Sensitivity (S+) and Signal to Noise Ratio (SNR).

An investigation of correlation between pilot scanning behavior and workload using stepwise regression analysis

NASA Technical Reports Server (NTRS)

Waller, M. C.

1976-01-01

An electro-optical device called an oculometer which tracks a subject's lookpoint as a time function has been used to collect data in a real-time simulation study of instrument landing system (ILS) approaches. The data describing the scanning behavior of a pilot during the instrument approaches have been analyzed by use of a stepwise regression analysis technique. A statistically significant correlation between pilot workload, as indicated by pilot ratings, and scanning behavior has been established. In addition, it was demonstrated that parameters derived from the scanning behavior data can be combined in a mathematical equation to provide a good representation of pilot workload.

Large Aperture Scanning Lidar Based on Holographic Optical Elements

NASA Technical Reports Server (NTRS)

Schwemmer, Geary K.; Miller, David O.; Wilkerson, Thomas D.; Andrus, Ionio; Guerra, David V.; Einaudi, Franco (Technical Monitor)

2001-01-01

Lidar remote sensing instruments can make a significant contribution to satisfying many of the required measurements of atmospheric and surface parameters for future spaceborne platforms, including topographic altimeters, atmospheric profiles of, wind, humidity, temperature, trace molecules, aerosols, and clouds. It is highly desirable to have wide measurement swaths for rapid coverage rather than just the narrow ribbon of data that is obtained with a nadir only observation. For most applications global coverage is required, and for wind measurements scanning or pointing is required in order to retrieve the full 3-D wind vector from multiple line-of-sight Doppler measurements. Conventional lidar receivers make up a substantial portion of the instrument's size and weight. Wide angle scanning typically requires a large scanning mirror in front of the receiver telescope, or pointing the entire telescope and aft optics assembly, Either of these methods entails the use of large bearings, motors, gearing and their associated electronics. Spaceborne instruments also need reaction wheels to counter the torque applied to the spacecraft by these motions. NASA has developed simplified conical scanning telescopes using Holographic Optical Elements (HOEs) to reduce the size, mass, angular momentum, and cost of scanning lidar systems. NASA has developed two operating lidar systems based on 40 cm diameter HOEs. The first such system, named Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing (PHASERS) was a joint development between NASA Goddard Space Flight Center (GSFC) and the University of Maryland College Park. PHASERS is based on a reflection HOE for use at the doubled Nd:YAG laser wavelength of 532 nm and has recently undergone a number of design changes in a collaborative effort between GSFC and Saint Anselm College in New Hampshire. The next step was to develop IR transmission HOEs for use with the Nd:YAG fundamental in the Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE). The HOE spins like a compact disk in a large ring ball bearing. In an aircraft the HOE faces down, looking out through a window at an angle of 45 degrees off-nadir. The HOE diffracts 85% of the incident 532 nm light into a 160 micron spot at a focal length of 1 meter. HARLIE is a field deployable lidar measuring aerosol, cloud, and boundary layer backscatter for atmospheric research. It has flown several times and is also used from a ground-based trailer in an upward-looking mode. The HOE generates a 45 degree conical scan pattern by rotating at speeds up to 30 rpm. Like PHASERS, the HOE in HARLIE serves both as the laser collimating lens as well as the receiver telescope primary optic. The telescope is coupled to the receiver package via fiber optic. The transmitter is a diode pumped Nd:YAG laser operating at 1064 nm, delivering 1 mJ pulses at a 5 KHz rep-rate. The receiver has a 200 microradian field-of-view and a 0.5 nm optical bandpass. The photon counting data system utilizes a single Geiger-mode silicon avalanche photodiode detector, This new technology has also presented us with new data visualization challenges as well as new measurement techniques. The backscatter data obtained from a stationary (i.e. ground-based) scanning HOE lidar is on the surface of a cone, which when viewed over many consecutive scans can reveal atmospheric motions on this surface over time as the atmosphere advects over the site. In a moving platform such as an airplane or satellite, the data from consecutive scans cover different areas under the flight path, revealing atmospheric structure in 3-dimensions. An example of a visualization of HARLIE ground-based data is presented, showing aerosol backscatter on a 90 degree conical surface generated from one 360 degree scan of the lidar during the HOLO-1 field campaign on the afternoon of 10 March 1999. Higher backscatter levels are rendered as lighter signal against a dark background. Breaking Kelvin-Helmholtz waves are evident on the north side of the scan at an altitude of 10-11 km. Time series of successive scans made at regular intervals render unique views of atmospheric motions, from which vertical profiles of atmospheric wind vectors can be obtained using a unique data analysis approach. Wind vectors obtained from the lidar were compared with co-located radiosonde wind profiles during an intensive operating period in September-October 2000 at the Atmospheric Radiation Measurement Program's Southern Great Plains Central Facility.

Optical tomography of human skin with subcellular spatial and picosecond time resolution using intense near infrared femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Koenig, Karsten; Wollina, Uwe; Riemann, Iris; Peukert, Christiane; Halbhuber, Karl-Juergen; Konrad, Helga; Fischer, Peter; Fuenfstueck, Veronika; Fischer, Tobias W.; Elsner, Peter

2002-06-01

We describe the novel high resolution imaging tool DermaInspect 100 for non-invasive diagnosis of dermatological disorders based on multiphoton autofluorescence imaging (MAI)and second harmonic generation. Femtosecond laser pulses in the spectral range of 750 nm to 850 nm have been used to image in vitro and in vivo human skin with subcellular spatial and picosecond temporal resolution. The non-linear induced autofluorescence originates mainly from naturally endogenous fluorophores/protein structures like NAD(P)H, flavins, keratin, collagen, elastin, porphyrins and melanin. Second harmonic generation was observed in the stratum corneum and in the dermis. The system with a wavelength-tunable compact 80 MHz Ti:sapphire laser, a scan module with galvo scan mirrors, piezoelectric objective positioner, fast photon detector and time-resolved single photon counting unit was used to perform optical sectioning and 3D autofluorescence lifetime imaging (t-mapping). In addition, a modified femtosecond laser scanning microscope was involved in autofluorescence measurements. Tissues of patients with psoriasis, nevi, dermatitis, basalioma and melanoma have been investigated. Individual cells and skin structures could be clearly visualized. Intracellular components and connective tissue structures could be further characterized by tuning the excitation wavelength in the range of 750 nm to 850 nm and by calculation of mean fluorescence lifetimes per pixel and of particular regions of interest. The novel non-invasive imaging system provides 4D (x,y,z,t) optical biopsies with subcellular resolution and offers the possibility to introduce a further optical diagnostic method in dermatology.

Model-Based Angular Scan Error Correction of an Electrothermally-Actuated MEMS Mirror

PubMed Central

Zhang, Hao; Xu, Dacheng; Zhang, Xiaoyang; Chen, Qiao; Xie, Huikai; Li, Suiqiong

2015-01-01

In this paper, the actuation behavior of a two-axis electrothermal MEMS (Microelectromechanical Systems) mirror typically used in miniature optical scanning probes and optical switches is investigated. The MEMS mirror consists of four thermal bimorph actuators symmetrically located at the four sides of a central mirror plate. Experiments show that an actuation characteristics difference of as much as 4.0% exists among the four actuators due to process variations, which leads to an average angular scan error of 0.03°. A mathematical model between the actuator input voltage and the mirror-plate position has been developed to predict the actuation behavior of the mirror. It is a four-input, four-output model that takes into account the thermal-mechanical coupling and the differences among the four actuators; the vertical positions of the ends of the four actuators are also monitored. Based on this model, an open-loop control method is established to achieve accurate angular scanning. This model-based open loop control has been experimentally verified and is useful for the accurate control of the mirror. With this control method, the precise actuation of the mirror solely depends on the model prediction and does not need the real-time mirror position monitoring and feedback, greatly simplifying the MEMS control system. PMID:26690432

1550 nm superluminescent diode and anti-Stokes effect CCD camera based optical coherence tomography for full-field optical metrology

NASA Astrophysics Data System (ADS)

Kredzinski, Lukasz; Connelly, Michael J.

2011-06-01

Optical Coherence Tomography (OCT) is a promising non-invasive imaging technology capable of carrying out 3D high-resolution cross-sectional images of the internal microstructure of examined material. However, almost all of these systems are expensive, requiring the use of complex optical setups, expensive light sources and complicated scanning of the sample under test. In addition most of these systems have not taken advantage of the competitively priced optical components available at wavelength within the main optical communications band located in the 1550 nm region. A comparatively simple and inexpensive full-field OCT system (FF-OCT), based on a superluminescent diode (SLD) light source and anti-stokes imaging device was constructed, to perform 3D cross-sectional imaging. This kind of inexpensive setup with moderate resolution could be easily applicable in low-level biomedical and industrial diagnostics. This paper involves calibration of the system and determines its suitability for imaging structures of biological tissues such as teeth, which has low absorption at 1550 nm.

Automatic neutron dosimetry system based on fluorescent nuclear track detector technology.

PubMed

Akselrod, M S; Fomenko, V V; Bartz, J A; Haslett, T L

2014-10-01

For the first time, the authors are describing an automatic fluorescent nuclear track detector (FNTD) reader for neutron dosimetry. FNTD is a luminescent integrating type of detector made of aluminium oxide crystals that does not require electronics or batteries during irradiation. Non-destructive optical readout of the detector is performed using a confocal laser scanning fluorescence imaging with near-diffraction limited resolution. The fully automatic table-top reader allows one to load up to 216 detectors on a tray, read their engraved IDs using a CCD camera and optical character recognition, scan and process simultaneously two types of images in fluorescent and reflected laser light contrast to eliminate false-positive tracks related to surface and volume crystal imperfections. The FNTD dosimetry system allows one to measure neutron doses from 0.1 mSv to 20 Sv and covers neutron energies from thermal to 20 MeV. The reader is characterised by a robust, compact optical design, fast data processing electronics and user-friendly software. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Laser scanning confocal microscope with programmable amplitude, phase, and polarization of the illumination beam.

PubMed

Boruah, B R; Neil, M A A

2009-01-01

We describe the design and construction of a laser scanning confocal microscope with programmable beam forming optics. The amplitude, phase, and polarization of the laser beam used in the microscope can be controlled in real time with the help of a liquid crystal spatial light modulator, acting as a computer generated hologram, in conjunction with a polarizing beam splitter and two right angled prisms assembly. Two scan mirrors, comprising an on-axis fast moving scan mirror for line scanning and an off-axis slow moving scan mirror for frame scanning, configured in a way to minimize the movement of the scanned beam over the pupil plane of the microscope objective, form the XY scan unit. The confocal system, that incorporates the programmable beam forming unit and the scan unit, has been implemented to image in both reflected and fluorescence light from the specimen. Efficiency of the system to programmably generate custom defined vector beams has been demonstrated by generating a bottle structured focal volume, which in fact is the overlap of two cross polarized beams, that can simultaneously improve both the lateral and axial resolutions if used as the de-excitation beam in a stimulated emission depletion confocal microscope.

Digital holographic tomography based on spectral interferometry.

PubMed

Yu, Lingfeng; Chen, Zhongping

2007-10-15

A digital holographic tomography system has been developed with the use of an inexpensive broadband light source and a fiber-based spectral interferometer. Multiple synthesized holograms (or object wave fields) of different wavelengths are obtained by transversely scanning a probe beam. The acquisition speed is improved compared with conventional wavelength-scanning digital holographic systems. The optical field of a volume around the object location is calculated by numerical diffraction from each synthesized hologram, and all such field volumes are numerically superposed to create the three-dimensional tomographic image. Experiments were performed to demonstrate the idea.

PScan 1.0: flexible software framework for polygon based multiphoton microscopy

NASA Astrophysics Data System (ADS)

Li, Yongxiao; Lee, Woei Ming

2016-12-01

Multiphoton laser scanning microscopes exhibit highly localized nonlinear optical excitation and are powerful instruments for in-vivo deep tissue imaging. Customized multiphoton microscopy has a significantly superior performance for in-vivo imaging because of precise control over the scanning and detection system. To date, there have been several flexible software platforms catered to custom built microscopy systems i.e. ScanImage, HelioScan, MicroManager, that perform at imaging speeds of 30-100fps. In this paper, we describe a flexible software framework for high speed imaging systems capable of operating from 5 fps to 1600 fps. The software is based on the MATLAB image processing toolbox. It has the capability to communicate directly with a high performing imaging card (Matrox Solios eA/XA), thus retaining high speed acquisition. The program is also designed to communicate with LabVIEW and Fiji for instrument control and image processing. Pscan 1.0 can handle high imaging rates and contains sufficient flexibility for users to adapt to their high speed imaging systems.

3D scanning characteristics of an amorphous silicon position sensitive detector array system.

PubMed

Contreras, Javier; Gomes, Luis; Filonovich, Sergej; Correia, Nuno; Fortunato, Elvira; Martins, Rodrigo; Ferreira, Isabel

2012-02-13

The 3D scanning electro-optical characteristics of a data acquisition prototype system integrating a 32 linear array of 1D amorphous silicon position sensitive detectors (PSD) were analyzed. The system was mounted on a platform for imaging 3D objects using the triangulation principle with a sheet-of-light laser. New obtained results reveal a minimum possible gap or simulated defect detection of approximately 350 μm. Furthermore, a first study of the angle for 3D scanning was also performed, allowing for a broad range of angles to be used in the process. The relationship between the scanning angle of the incident light onto the object and the image displacement distance on the sensor was determined for the first time in this system setup. Rendering of 3D object profiles was performed at a significantly higher number of frames than in the past and was possible for an incident light angle range of 15 ° to 85 °.

Wide-band acousto-optic deflectors for large field of view two-photon microscope.

PubMed

Jiang, Runhua; Zhou, Zhenqiao; Lv, Xiaohua; Zeng, Shaoqun

2012-04-01

Acousto-optic deflector (AOD) is an attractive scanner for two-photon microscopy because it can provide fast and versatile laser scanning and does not involve any mechanical movements. However, due to the small scan range of available AOD, the field of view (FOV) of the AOD-based microscope is typically smaller than that of the conventional galvanometer-based microscope. Here, we developed a novel wide-band AOD to enlarge the scan angle. Considering the maximum acceptable acoustic attenuation in the acousto-optic crystal, relatively lower operating frequencies and moderate aperture were adopted. The custom AOD was able to provide 60 MHz 3-dB bandwidth and 80% peak diffraction efficiency at 840 nm wavelength. Based on a pair of such AOD, a large FOV two-photon microscope was built with a FOV up to 418.5 μm (40× objective). The spatiotemporal dispersion was compensated simultaneously with a single custom-made prism. By means of dynamic power modulation, the variation of laser intensity within the FOV was reduced below 5%. The lateral and axial resolution of the system were 0.58-2.12 μm and 2.17-3.07 μm, respectively. Pollen grain images acquired by this system were presented to demonstrate the imaging capability at different positions across the entire FOV. © 2012 American Institute of Physics

Lasers for Training Devices.

ERIC Educational Resources Information Center

Fuller, C. A.

A breadboard model of a laser display system is described in detail and its operating procedure is outlined. The system consists of: a Model 52 argon krypton ion laser and power supply; an optical breadboard comprising a pocket cell light modulator, a galvonmeter beam deflector for vertical scanning, a unique multiple reflection beam steerer for…

Multi-function optical characterization and inspection of MEMS components using stroboscopic coherence scanning interferometry

NASA Astrophysics Data System (ADS)

Tapilouw, Abraham Mario; Chen, Liang-Chia; Xuan-Loc, Nguyen; Chen, Jin-Liang

2014-08-01

A Micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and automotive industries. However, effective inspection systems are also needed to ensure the functional reliability of MEMS. This study developed a stroboscopic coherence scanning Interferometry (SCSI) technique for measuring key characteristics typically used as criteria in MEMS inspections. Surface profiles of MEMS both static and dynamic conditions were measured by means of coherence scanning Interferometry (CSI). Resonant frequencies of vibrating MEMS were measured by deformation of interferogram fringes for out-of-plane vibration and by image correlation for in-plane vibration. The measurement bandwidth of the developed system can be tuned up to three megahertz or higher for both in-plane and out-of-plane measurement of MEMS.

Characterization of ultrafast devices using novel optical techniques

NASA Astrophysics Data System (ADS)

Ali, Md Ershad

Optical techniques have been extensively used to examine the high frequency performance of a number of devices including High Electron Mobility Transistors (HEMTs), Heterojunction Bipolar Phototransistors (HPTs) and Low Temperature GaAs (LT-GaAs) Photoconductive Switches. To characterize devices, frequency and time domain techniques, namely optical heterodyning and electro-optic sampling, having measurement bandwidths in excess of 200 GHz, were employed. Optical mixing in three-terminal devices has been extended for the first time to submillimeter wave frequencies. Using a new generation of 50-nm gate pseudomorphic InP-based HEMTs, optically mixed signals were detected to 552 GHz with a signal-to-noise ratio of approximately 5 dB. To the best of our knowledge, this is the highest frequency optical mixing obtained in three- terminal devices to date. A novel harmonic three-wave detection scheme was used for the detection of the optically generated signals. The technique involved downconversion of the signal in the device by the second harmonic of a gate-injected millimeter wave local oscillator. Measurements were also conducted up to 212 GHz using direct optical mixing and up to 382 GHz using a fundamental three-wave detection scheme. New interesting features in the bias dependence of the optically mixed signals have been reported. An exciting novel development from this work is the successful integration of near-field optics with optical heterodyning. The technique, called near-field optical heterodyning (NFOH), allows for extremely localized injection of high-frequency stimulus to any arbitrary point of an ultrafast device or circuit. Scanning the point of injection across the sample provides details of the high frequency operation of the device with high spatial resolution. For the implementation of the technique, fiber-optic probes with 100 nm apertures were fabricated. A feedback controlled positioning system was built for accurate placement and scanning of the fiber probe with nanometric precision. The applicability of the NFOH technique was first confirmed by measurements on heterojunction phototransistors at 100 GHz. Later NFOH scans were performed at 63 GHz on two other important devices, HEMTs and LT-GaAs Photoconductive Switches. Spatially resolved response characteristics of these devices revealed interesting details of their operation.

PINPIN a-Si:H based structures for X-ray image detection using the laser scanning technique

NASA Astrophysics Data System (ADS)

Fernandes, M.; Vygranenko, Y.; Vieira, M.

2015-05-01

Conventional film based X-ray imaging systems are being replaced by their digital equivalents. Different approaches are being followed by considering direct or indirect conversion, with the later technique dominating. The typical, indirect conversion, X-ray panel detector uses a phosphor for X-ray conversion coupled to a large area array of amorphous silicon based optical sensors and a couple of switching thin film transistors (TFT). The pixel information can then be readout by switching the correspondent line and column transistors, routing the signal to an external amplifier. In this work we follow an alternative approach, where the electrical switching performed by the TFT is replaced by optical scanning using a low power laser beam and a sensing/switching PINPIN structure, thus resulting in a simpler device. The optically active device is a PINPIN array, sharing both front and back electrical contacts, deposited over a glass substrate. During X-ray exposure, each sensing side photodiode collects photons generated by the scintillator screen (560 nm), charging its internal capacitance. Subsequently a laser beam (445 nm) scans the switching diodes (back side) retrieving the stored charge in a sequential way, reconstructing the image. In this paper we present recent work on the optoelectronic characterization of the PINPIN structure to be incorporated in the X-ray image sensor. The results from the optoelectronic characterization of the device and the dependence on scanning beam parameters are presented and discussed. Preliminary results of line scans are also presented.

Studies on 2-amino-5-nitropyridinium nitrate (2A5NPN): A semi-organic third order nonlinear optical single crystal

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

Sivasubramani, V.; Pandian, Muthu Senthil, E-mail: senthilpandianm@ssn.edu.in; Ramasamy, P.

2016-05-23

2-amino-5-nitropyridinium nitrate (2A5NPN) is a semi-organic nonlinear optical crystal and optically good quality 2A5NPN single crystals were successfully grown by slow evaporation solution growth technique (SEST) at ambient temperature. The crystallographic structure of the grown crystal was determined by single crystal X-Ray diffraction analysis and it belongs to Monoclinic crystal system with centro symmetric crystalline nature. The crystallinity of the grown crystal was confirmed by powder X-ray diffraction analysis. The other physical properties of grown crystals are also characterized using TG-DTA, UV-Visible NIR, chemical etching, photoconductivity and Z-scan measurements. The Z-scan method reveals that the 2A5NPN crystal possesses multi photonmore » absorption behaviour and the significantly higher third order susceptibility and it is a promising potential NLO material.« less

Non-linear optical flow cytometry using a scanned, Bessel beam light-sheet.

PubMed

Collier, Bradley B; Awasthi, Samir; Lieu, Deborah K; Chan, James W

2015-05-29

Modern flow cytometry instruments have become vital tools for high-throughput analysis of single cells. However, as issues with the cellular labeling techniques often used in flow cytometry have become more of a concern, the development of label-free modalities for cellular analysis is increasingly desired. Non-linear optical phenomena (NLO) are of growing interest for label-free analysis because of the ability to measure the intrinsic optical response of biomolecules found in cells. We demonstrate that a light-sheet consisting of a scanned Bessel beam is an optimal excitation geometry for efficiently generating NLO signals in a microfluidic environment. The balance of photon density and cross-sectional area provided by the light-sheet allowed significantly larger two-photon fluorescence intensities to be measured in a model polystyrene microparticle system compared to measurements made using other excitation focal geometries, including a relaxed Gaussian excitation beam often used in conventional flow cytometers.

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.

Neurosurgical hand-held optical coherence tomography (OCT) forward-viewing probe

NASA Astrophysics Data System (ADS)

Sun, Cuiru; Lee, Kenneth K. C.; Vuong, Barry; Cusimano, Michael; Brukson, Alexander; Mariampillai, Adrian; Standish, Beau A.; Yang, Victor X. D.

2012-02-01

A prototype neurosurgical hand-held optical coherence tomography (OCT) imaging probe has been developed to provide micron resolution cross-sectional images of subsurface tissue during open surgery. This new ergonomic hand-held probe has been designed based on our group's previous work on electrostatically driven optical fibers. It has been packaged into a catheter probe in the familiar form factor of the clinically accepted Bayonet shaped neurosurgical non-imaging Doppler ultrasound probes. The optical design was optimized using ZEMAX simulation. Optical properties of the probe were tested to yield an ~20 um spot size, 5 mm working distance and a 3.5 mm field of view. The scan frequency can be increased or decreased by changing the applied voltage. Typically a scan frequency of less than 60Hz is chosen to keep the applied voltage to less than 2000V. The axial resolution of the probe was ~15 um (in air) as determined by the OCT system. A custom-triggering methodology has been developed to provide continuous stable imaging, which is crucial for clinical utility. Feasibility of this probe, in combination with a 1310 nm swept source OCT system was tested and images are presented to highlight the usefulness of such a forward viewing handheld OCT imaging probe. Knowledge gained from this research will lay the foundation for developing new OCT technologies for endovascular management of cerebral aneurysms and transsphenoidal neuroendoscopic treatment of pituitary tumors.

Microscanners for optical endomicroscopic applications

NASA Astrophysics Data System (ADS)

Hwang, Kyungmin; Seo, Yeong-Hyeon; Jeong, Ki-Hun

2017-12-01

MEMS laser scanning enables the miniaturization of endoscopic catheters for advanced endomicroscopy such as confocal microscopy, multiphoton microscopy, optical coherence tomography, and many other laser scanning microscopy. These advanced biomedical imaging modalities open a great potential for in vivo optical biopsy without surgical excision. They have huge capabilities for detecting on-demand early stage cancer with non-invasiveness. In this article, the scanning arrangement, trajectory, and actuation mechanism of endoscopic microscanners and their endomicroscopic applications will be overviewed.

White light Z-scan measurements of ultrafast optical nonlinearity in reduced graphene oxide nanosheets in the 400–700 nm region

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

Perumbilavil, Sreekanth; Sankar, Pranitha; Priya Rose, T.

Wavelength dispersion of optical power limiting is an important factor to be considered while designing potential optical limiters for laser safety applications. We report the observation of broadband, ultrafast optical limiting in reduced graphene oxide (rGO), measured by a single open aperture Z-scan using a white light continuum (WLC) source. WLC Z-scan is fast when the nonlinearity is to be measured over broad wavelength ranges, and it obviates the need for an ultrafast tunable laser making it cost-economic compared to conventional Z-scan. The nonlinearity arises from nondegenerate two-photon absorption, owing mostly to the crystallinity and extended π conjugation of rGO.

Optical CT imaging of solid radiochromic dosimeters in mismatched refractive index solutions using a scanning laser and large area detector

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

Dekker, Kurtis H., E-mail: kdekker2@uwo.ca

Purpose: The practical use of the PRESAGE® solid plastic dosimeter is limited by the inconvenience of immersing it in high-viscosity oils to achieve refractive index matching for optical computed tomography (CT) scanning. The oils are slow to mix and difficult to clean from surfaces, and the dosimeter rotation can generate dynamic Schlieren inhomogeneity patterns in the reference liquid, limiting the rotational and overall scan speed. Therefore, it would be beneficial if lower-viscosity, water-based solutions with slightly unmatched refractive index could be used instead. The purpose of this work is to demonstrate the feasibility of allowing mismatched conditions when using amore » scanning laser system with a large acceptance angle detector. A fiducial-based ray path measurement technique is combined with an iterative CT reconstruction algorithm to reconstruct images. Methods: A water based surrounding liquid with a low viscosity was selected for imaging PRESAGE® solid dosimeters. Liquid selection was optimized to achieve as high a refractive index as possible while avoiding rotation-induced Schlieren effects. This led to a refractive index mismatch of 6% between liquid and dosimeters. Optical CT scans were performed with a fan-beam scanning-laser optical CT system with a large area detector to capture most of the refracted rays. A fiducial marker placed on the wall of a cylindrical sample occludes a given light ray twice. With knowledge of the rotation angle and the radius of the cylindrical object, the actual internal path of each ray through the dosimeter can be calculated. Scans were performed with 1024 projections of 512 data samples each, and rays were rebinned to form 512 parallel-beam projections. Reconstructions were performed on a 512 × 512 grid using 100 iterations of the SIRT iterative CT algorithm. Proof of concept was demonstrated with a uniformly attenuating solution phantom. PRESAGE® dosimeters (11 cm diameter) were irradiated with Cobalt-60 irradiator to achieve either a uniform dose or a 2-level “step-dose” pattern. Results: With 6% refractive index mismatching, a circular field of view of 85% of the diameter of a cylindrical sample can be reconstructed accurately. Reconstructed images of the test solution phantom were uniform (within 3%) inside this radius. However, the dose responses of the PRESAGE® samples were not spatially uniform, with variations of at least 5% in sensitivity. The variation appears as a “cupping” artifact with less sensitivity in the middle than at the periphery of the PRESAGE® cylinder. Polarization effects were also detected for these samples. Conclusions: The fiducial-based ray path measurement scheme, coupled with an iterative reconstruction algorithm, enabled optical CT scanning of PRESAGE® dosimeters immersed in mismatched refractive index solutions. However, improvements to PRESAGE® dose response uniformity are required.« less

Method and apparatus for chemical and topographical microanalysis

NASA Technical Reports Server (NTRS)

Kossakovski, Dmitri A. (Inventor); Baldeschwieler, John D. (Inventor); Beauchamp, Jesse L. (Inventor)

2002-01-01

A scanning probe microscope is combined with a laser induced breakdown spectrometer to provide spatially resolved chemical analysis of the surface correlated with the surface topography. Topographical analysis is achieved by scanning a sharp probe across the sample at constant distance from the surface. Chemical analysis is achieved by the means of laser induced breakdown spectroscopy by delivering pulsed laser radiation to the sample surface through the same sharp probe, and consequent collection and analysis of emission spectra from plasma generated on the sample by the laser radiation. The method comprises performing microtopographical analysis of the sample with a scanning probe, selecting a scanned topological site on the sample, generating a plasma plume at the selected scanned topological site, and measuring a spectrum of optical emission from the plasma at the selected scanned topological site. The apparatus comprises a scanning probe, a pulsed laser optically coupled to the probe, an optical spectrometer, and a controller coupled to the scanner, laser and spectrometer for controlling the operation of the scanner, laser and spectrometer. The probe and scanner are used for topographical profiling the sample. The probe is also used for laser radiation delivery to the sample for generating a plasma plume from the sample. Optical emission from the plasma plume is collected and delivered to the optical spectrometer so that analysis of emission spectrum by the optical spectrometer allows for identification of chemical composition of the sample at user selected sites.

Axonal loss from acute optic neuropathy documented by scanning laser polarimetry

PubMed Central

Meier, F M; Bernasconi, P; Stürmer, J; Caubergh, M-J; Landau, K

2002-01-01

Background/aims: Retinal nerve fibre layer analysis by scanning laser polarimetry has been shown to facilitate diagnosis of glaucoma while its role in glaucoma follow up is still unclear. A major difficulty is the slow reduction of retinal nerve fibre layer thickness in glaucomatous optic neuropathy. Eyes of patients were studied after acute retrobulbar optic nerve lesion in order to evaluate the usefulness of scanning laser polarimetry in documenting retinal nerve fibre layer loss over time. Methods: Five patients who suffered severe retrobulbar optic neuropathy have had repeated measurements of the retinal nerve fibre layer using scanning laser polarimetry at various intervals, the first examination being within 1 week of injury. Results: All eyes showed a marked decrease in peripapillary retinal nerve fibre layer thickness, which followed an exponential curve and occurred predominantly within 8 weeks of injury. Compared to a previous study using red-free photographs, scanning laser polarimetry showed retinal nerve fibre layer loss earlier in the course of descending atrophy. Conclusion: Scanning laser polarimetry is useful for early detection and documentation of retinal nerve fibre layer loss following acute injury to the retrobulbar optic nerve. It seems to be a promising tool for follow up of individual glaucoma patients. PMID:11864884

Optical sectioning for optical scanning holography using phase-space filtering with Wigner distribution functions.

PubMed

Kim, Hwi; Min, Sung-Wook; Lee, Byoungho; Poon, Ting-Chung

2008-07-01

We propose a novel optical sectioning method for optical scanning holography, which is performed in phase space by using Wigner distribution functions together with the fractional Fourier transform. The principle of phase-space optical sectioning for one-dimensional signals, such as slit objects, and two-dimensional signals, such as rectangular objects, is first discussed. Computer simulation results are then presented to substantiate the proposed idea.

High speed spectral domain optical coherence tomography for retinal imaging at 500,000 A‑lines per second

PubMed Central

An, Lin; Li, Peng; Shen, Tueng T.; Wang, Ruikang

2011-01-01

We present a new development of ultrahigh speed spectral domain optical coherence tomography (SDOCT) for human retinal imaging at 850 nm central wavelength by employing two high-speed line scan CMOS cameras, each running at 250 kHz. Through precisely controlling the recording and reading time periods of the two cameras, the SDOCT system realizes an imaging speed at 500,000 A-lines per second, while maintaining both high axial resolution (~8 μm) and acceptable depth ranging (~2.5 mm). With this system, we propose two scanning protocols for human retinal imaging. The first is aimed to achieve isotropic dense sampling and fast scanning speed, enabling a 3D imaging within 0.72 sec for a region covering 4x4 mm2. In this case, the B-frame rate is 700 Hz and the isotropic dense sampling is 500 A-lines along both the fast and slow axes. This scanning protocol minimizes the motion artifacts, thus making it possible to perform two directional averaging so that the signal to noise ratio of the system is enhanced while the degradation of its resolution is minimized. The second protocol is designed to scan the retina in a large field of view, in which 1200 A-lines are captured along both the fast and slow axes, covering 10 mm2, to provide overall information about the retinal status. Because of relatively long imaging time (4 seconds for a 3D scan), the motion artifact is inevitable, making it difficult to interpret the 3D data set, particularly in a way of depth-resolved en-face fundus images. To mitigate this difficulty, we propose to use the relatively high reflecting retinal pigmented epithelium layer as the reference to flatten the original 3D data set along both the fast and slow axes. We show that the proposed system delivers superb performance for human retina imaging. PMID:22025983

High speed spectral domain optical coherence tomography for retinal imaging at 500,000 A‑lines per second.

PubMed

An, Lin; Li, Peng; Shen, Tueng T; Wang, Ruikang

2011-10-01

We present a new development of ultrahigh speed spectral domain optical coherence tomography (SDOCT) for human retinal imaging at 850 nm central wavelength by employing two high-speed line scan CMOS cameras, each running at 250 kHz. Through precisely controlling the recording and reading time periods of the two cameras, the SDOCT system realizes an imaging speed at 500,000 A-lines per second, while maintaining both high axial resolution (~8 μm) and acceptable depth ranging (~2.5 mm). With this system, we propose two scanning protocols for human retinal imaging. The first is aimed to achieve isotropic dense sampling and fast scanning speed, enabling a 3D imaging within 0.72 sec for a region covering 4x4 mm(2). In this case, the B-frame rate is 700 Hz and the isotropic dense sampling is 500 A-lines along both the fast and slow axes. This scanning protocol minimizes the motion artifacts, thus making it possible to perform two directional averaging so that the signal to noise ratio of the system is enhanced while the degradation of its resolution is minimized. The second protocol is designed to scan the retina in a large field of view, in which 1200 A-lines are captured along both the fast and slow axes, covering 10 mm(2), to provide overall information about the retinal status. Because of relatively long imaging time (4 seconds for a 3D scan), the motion artifact is inevitable, making it difficult to interpret the 3D data set, particularly in a way of depth-resolved en-face fundus images. To mitigate this difficulty, we propose to use the relatively high reflecting retinal pigmented epithelium layer as the reference to flatten the original 3D data set along both the fast and slow axes. We show that the proposed system delivers superb performance for human retina imaging.

Dynamic focus-tracking MEMS scanning micromirror with low actuation voltages for endoscopic imaging.

PubMed

Strathman, Matthew; Liu, Yunbo; Li, Xingde; Lin, Lih Y

2013-10-07

We demonstrate a 3-D scanning micromirror device that combines 2-D beam scanning with focus control in the same device using micro-electro-mechanical-systems (MEMS) technology. 2-D beam scanning is achieved with a biaxial gimbal structure and focus control is obtained with a deformable mirror membrane surface. The micromirror with 800 micrometer diameter is designed to be sufficiently compact and efficient so that it can be incorporated into an endoscopic imaging probe in the future. The design, fabrication and characterization of the device are described in this paper. Using the focus-tracking MEMS scanning mirror, we achieved an optical scanning range of >16 degrees with <40 V actuation voltage at resonance and a tunable focal length between infinity and 25 mm with <100V applied bias.

Optical Coherence Tomography Evaluation in the Multicenter Uveitis Steroid Treatment (MUST) Trial

PubMed Central

Domalpally, Amitha; Altaweel, Michael M.; Kempen, John H.; Myers, Dawn; Davis, Janet L; Foster, C Stephen; Latkany, Paul; Srivastava, Sunil K.; Stawell, Richard J.; Holbrook, Janet T.

2013-01-01

Purpose To describe the evaluation of optical coherence tomography (OCT) scans in the Muliticenter Uveitis Steroid Treatment (MUST) trial and report baseline OCT features of enrolled participants. Methods Time domain OCTs acquired by certified photographers using a standardized scan protocol were evaluated at a Reading Center. Accuracy of retinal thickness data was confirmed with quality evaluation and caliper measurement of centerpoint thickness (CPT) was performed when unreliable. Morphological evaluation included cysts, subretinal fluid,epiretinal membranes (ERMs),and vitreomacular traction. Results Of the 453 OCTs evaluated, automated retinal thickness was accurate in 69.5% of scans, caliper measurement was performed in 26%,and 4% were ungradable. Intraclass correlation was 0.98 for reproducibility of caliper measurement. Macular edema (centerpoint thickness ≥ 240um) was present in 36%. Cysts were present in 36.6% of scans and ERMs in 27.8%, predominantly central. Intergrader agreement ranged from 78 − 82% for morphological features. Conclusion Retinal thickness data can be retrieved in a majority of OCT scans in clinical trial submissions for uveitis studies. Small cysts and ERMs involving the center are common in intermediate and posterior/panuveitis requiring systemic corticosteroid therapy. PMID:23163490

Design of a cathodoluminescence image generator using a Raspberry Pi coupled to a scanning electron microscope.

PubMed

Benítez, Alfredo; Santiago, Ulises; Sanchez, John E; Ponce, Arturo

2018-01-01

In this work, an innovative cathodoluminescence (CL) system is coupled to a scanning electron microscope and synchronized with a Raspberry Pi computer integrated with an innovative processing signal. The post-processing signal is based on a Python algorithm that correlates the CL and secondary electron (SE) images with a precise dwell time correction. For CL imaging, the emission signal is collected through an optical fiber and transduced to an electrical signal via a photomultiplier tube (PMT). CL Images are registered in a panchromatic mode and can be filtered using a monochromator connected between the optical fiber and the PMT to produce monochromatic CL images. The designed system has been employed to study ZnO samples prepared by electrical arc discharge and microwave methods. CL images are compared with SE images and chemical elemental mapping images to correlate the emission regions of the sample.

Design of a cathodoluminescence image generator using a Raspberry Pi coupled to a scanning electron microscope

NASA Astrophysics Data System (ADS)

Benítez, Alfredo; Santiago, Ulises; Sanchez, John E.; Ponce, Arturo

2018-01-01

In this work, an innovative cathodoluminescence (CL) system is coupled to a scanning electron microscope and synchronized with a Raspberry Pi computer integrated with an innovative processing signal. The post-processing signal is based on a Python algorithm that correlates the CL and secondary electron (SE) images with a precise dwell time correction. For CL imaging, the emission signal is collected through an optical fiber and transduced to an electrical signal via a photomultiplier tube (PMT). CL Images are registered in a panchromatic mode and can be filtered using a monochromator connected between the optical fiber and the PMT to produce monochromatic CL images. The designed system has been employed to study ZnO samples prepared by electrical arc discharge and microwave methods. CL images are compared with SE images and chemical elemental mapping images to correlate the emission regions of the sample.

Scanning dimensional measurement using laser-trapped microsphere with optical standing-wave scale

NASA Astrophysics Data System (ADS)

Michihata, Masaki; Ueda, Shin-ichi; Takahashi, Satoru; Takamasu, Kiyoshi; Takaya, Yasuhiro

2017-06-01

We propose a laser trapping-based scanning dimensional measurement method for free-form surfaces. We previously developed a laser trapping-based microprobe for three-dimensional coordinate metrology. This probe performs two types of measurements: a tactile coordinate and a scanning measurement in the same coordinate system. The proposed scanning measurement exploits optical interference. A standing-wave field is generated between the laser-trapped microsphere and the measured surface because of the interference from the retroreflected light. The standing-wave field produces an effective length scale, and the trapped microsphere acts as a sensor to read this scale. A horizontal scan of the trapped microsphere produces a phase shift of the standing wave according to the surface topography. This shift can be measured from the change in the microsphere position. The dynamics of the trapped microsphere within the standing-wave field was estimated using a harmonic model, from which the measured surface can be reconstructed. A spherical lens was measured experimentally, yielding a radius of curvature of 2.59 mm, in agreement with the nominal specification (2.60 mm). The difference between the measured points and a spherical fitted curve was 96 nm, which demonstrates the scanning function of the laser trapping-based microprobe for free-form surfaces.

Nonlinear optical switching and optical limiting in colloidal CdSe quantum dots investigated by nanosecond Z-scan measurement

NASA Astrophysics Data System (ADS)

Valligatla, Sreeramulu; Haldar, Krishna Kanta; Patra, Amitava; Desai, Narayana Rao

2016-10-01

The semiconductor nanocrystals are found to be promising class of third order nonlinear optical materials because of quantum confinement effects. Here, we highlight the nonlinear optical switching and optical limiting of cadmium selenide (CdSe) quantum dots (QDs) using nanosecond Z-scan measurement. The intensity dependent nonlinear absorption and nonlinear refraction of CdSe QDs were investigated by applying the Z-scan technique with 532 nm, nanosecond laser pulses. At lower intensities, the nonlinear process is dominated by saturable absorption (SA) and it is changed to reverse saturable absorption (RSA) at higher intensities. The SA behaviour is attributed to the ground state bleaching and the RSA is ascribed to free carrier absorption (FCA) of CdSe QDs. The nonlinear optical switching behaviour and reverse saturable absorption makes CdSe QDs are good candidate for all-optical device and optical limiting applications.

An image‐based method to synchronize cone‐beam CT and optical surface tracking

PubMed Central

Schaerer, Joël; Riboldi, Marco; Sarrut, David; Baroni, Guido

2015-01-01

The integration of in‐room X‐ray imaging and optical surface tracking has gained increasing importance in the field of image guided radiotherapy (IGRT). An essential step for this integration consists of temporally synchronizing the acquisition of X‐ray projections and surface data. We present an image‐based method for the synchronization of cone‐beam computed tomography (CBCT) and optical surface systems, which does not require the use of additional hardware. The method is based on optically tracking the motion of a component of the CBCT/gantry unit, which rotates during the acquisition of the CBCT scan. A calibration procedure was implemented to relate the position of the rotating component identified by the optical system with the time elapsed since the beginning of the CBCT scan, thus obtaining the temporal correspondence between the acquisition of X‐ray projections and surface data. The accuracy of the proposed synchronization method was evaluated on a motorized moving phantom, performing eight simultaneous acquisitions with an Elekta Synergy CBCT machine and the AlignRT optical device. The median time difference between the sinusoidal peaks of phantom motion signals extracted from the synchronized CBCT and AlignRT systems ranged between ‐3.1 and 12.9 msec, with a maximum interquartile range of 14.4 msec. The method was also applied to clinical data acquired from seven lung cancer patients, demonstrating the potential of the proposed approach in estimating the individual and daily variations in respiratory parameters and motion correlation of internal and external structures. The presented synchronization method can be particularly useful for tumor tracking applications in extracranial radiation treatments, especially in the field of patient‐specific breathing models, based on the correlation between internal tumor motion and external surface surrogates. PACS number: 87

Virtobot--a multi-functional robotic system for 3D surface scanning and automatic post mortem biopsy.

PubMed

Ebert, Lars Christian; Ptacek, Wolfgang; Naether, Silvio; Fürst, Martin; Ross, Steffen; Buck, Ursula; Weber, Stefan; Thali, Michael

2010-03-01

The Virtopsy project, a multi-disciplinary project that involves forensic science, diagnostic imaging, computer science, automation technology, telematics and biomechanics, aims to develop new techniques to improve the outcome of forensic investigations. This paper presents a new approach in the field of minimally invasive virtual autopsy for a versatile robotic system that is able to perform three-dimensional (3D) surface scans as well as post mortem image-guided soft tissue biopsies. The system consists of an industrial six-axis robot with additional extensions (i.e. a linear axis to increase working space, a tool-changing system and a dedicated safety system), a multi-slice CT scanner with equipment for angiography, a digital photogrammetry and 3D optical surface-scanning system, a 3D tracking system, and a biopsy end effector for automatic needle placement. A wax phantom was developed for biopsy accuracy tests. Surface scanning times were significantly reduced (scanning times cut in half, calibration three times faster). The biopsy module worked with an accuracy of 3.2 mm. Using the Virtobot, the surface-scanning procedure could be standardized and accelerated. The biopsy module is accurate enough for use in biopsies in a forensic setting. The Virtobot can be utilized for several independent tasks in the field of forensic medicine, and is sufficiently versatile to be adapted to different tasks in the future. (c) 2009 John Wiley & Sons, Ltd.

Micropaleontological studies of lunar and terrestrial precambrian materials

NASA Technical Reports Server (NTRS)

Schope, J. W.

1974-01-01

Optical microscopic and scanning electron microscopic studies of rock chips and dust returned by Apollo 14, 15, 16, and 17 are analyzed along with optical microscopic studies of petrographic thin sections of breccias and basalts returned by Apollo 14, 15, and 16. Results show no evidence of modern or fossil lunar organisms. The lunar surface is now, and apparently has been throughout the geologic past, inimical to known biologic systems.

Analysis of particulate contamination on tape lift samples from the VETA optical surfaces

NASA Technical Reports Server (NTRS)

Germani, Mark S.

1992-01-01

Particulate contamination analysis was carried out on samples taken from the Verification Engineering Test Article (VETA) x-ray detection system. A total of eighteen tape lift samples were taken from the VETA optical surfaces. Initially, the samples were tested using a scanning electron microscope. Additionally, particle composition was determined by energy dispersive x-ray spectrometry. Results are presented in terms of particle loading per sample.

Endoscopic optical coherence tomography with a modified microelectromechanical systems mirror for detection of bladder cancers

NASA Astrophysics Data System (ADS)

Xie, Tuqiang; Xie, Huikai; Fedder, Gary K.; Pan, Yingtian

2003-11-01

Experimental results of a modified micromachined microelectromechanical systems (MEMS) mirror for substantial enhancement of the transverse laser scanning performance of endoscopic optical coherence tomography (EOCT) are presented. Image distortion due to buckling of MEMS mirror in our previous designs was analyzed and found to be attributed to excessive internal stress of the transverse bimorph meshes. The modified MEMS mirror completely eliminates bimorph stress and the resultant buckling effect, which increases the wobbling-free angular optical actuation to greater than 37°, exceeding the transverse laser scanning requirements for EOCT and confocal endoscopy. The new optical coherence tomography (OCT) endoscope allows for two-dimensional cross-sectional imaging that covers an area of 4.2 mm × 2.8 mm (limited by scope size) and at roughly 5 frames/s instead of the previous area size of 2.9 mm × 2.8 mm and is highly suitable for noninvasive and high-resolution imaging diagnosis of epithelial lesions in vivo. EOCT images of normal rat bladders and rat bladder cancers are compared with the same cross sections acquired with conventional bench-top OCT. The results clearly demonstrate the potential of EOCT for in vivo imaging diagnosis and precise guidance for excisional biopsy of early bladder cancers.

Nonlinear ultrafast optical response in organic molecular crystals

NASA Astrophysics Data System (ADS)

Rahman, Talat S.; Turkowski, Volodymyr; Leuenberger, Michael N.

2012-02-01

We analyze possible nonlinear excitonic effects in the organic molecule crystals by using a combined time-dependent DFT and many-body approach. In particular, we analyze possible effects of the time-dependent (retarded)interaction between different types of excitations, Frenkel excitons, charge transfer excitons and excimers, on the electric and the optical response of the system. We pay special attention to the case of constant electric field and ultrafast pulses, including that of four-wave mixing experiments. As a specific application we examine the optical excitations of pentacene nanocrystals and compare the results with available experimental data.[1] Our results demostrate that the nonlinear effects can play an important role in the optical response of these systems. [1] A. Kabakchiev, ``Scanning Tunneling Luminescence of Pentacene Nanocrystals'', PhD Thesis (EPFL, Lausanne, 2010).

Studies on the growth aspects, structural, thermal, dielectric and third order nonlinear optical properties of solution grown 4-methylpyridinium p-nitrophenolate single crystal

NASA Astrophysics Data System (ADS)

Devi, S. Reena; Kalaiyarasi, S.; Zahid, I. MD.; Kumar, R. Mohan

2016-11-01

An ionic organic optical crystal of 4-methylpyridinium p-nitrophenolate was grown from methanol by slow evaporation method at ambient temperature. Powder and single crystal X-ray diffraction studies revealed the crystal system and its crystalline perfection. The rocking curve recorded from HRXRD study confirmed the crystal quality. FTIR spectral analysis confirmed the functional groups present in the title compound. UV-visible spectral study revealed the optical window and band gap of grown crystal. The thermal, electrical and surface laser damage threshold properties of harvested crystal were examined by using TGA/DTA, LCR/Impedance Analyzer and Nd:YAG laser system respectively. The third order nonlinear optical property of grown crystal was elucidated by Z-scan technique.

Nonlinear Optical Properties and Applications of Polydiacetylene

NASA Technical Reports Server (NTRS)

Abdeldayem, Hossin; Paley, Mark S.; Witherow, William K.; Frazier, Donald O.

2000-01-01

Recently, we have demonstrated a picosecond all-optical switch, which also functions as a partial all-optical NAND logic gate using a novel polydiacetylene that is synthesized in our laboratory. The nonlinear optical properties of the polydiacetylene material are measured using the Z-scan technique. A theoretical model based on a three level system is investigated and the rate equations of the system are solved. The theoretical calculations are proven to match nicely with the experimental results. The absorption cross-sections for both the first and higher excited states are estimated. The analyses also show that the material suffers a photochemical change beyond a certain level of the laser power and its physical properties suffer radical changes. These changes are the cause for the partial NAND gate function and the switching mechanism.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P [Los Alamos, NM; Chernobrod, Boris M [Los Alamos, NM

2010-06-29

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P.; Chernobrod, Boris M.

2009-11-10

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of impaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P.; Chernobrod, Boris M.

2007-12-11

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P [Los Alamos, NM; Chernobrod, Boris M [Los Alamos, NM

2010-07-13

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P [Los Alamos, NM; Chernobrod, Boris M [Los Alamos, NM

2009-10-27

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Dental image replacement on cone beam computed tomography with three-dimensional optical scanning of a dental cast, occlusal bite, or bite tray impression.

PubMed

Kang, S-H; Lee, J-W; Lim, S-H; Kim, Y-H; Kim, M-K

2014-10-01

The goal of the present study was to compare the accuracy of dental image replacement on a cone beam computed tomography (CBCT) image using digital image data from three-dimensional (3D) optical scanning of a dental cast, occlusal bite, and bite tray impression. A Bracket Typodont dental model was used. CBCT of the dental model was performed and the data were converted to stereolithography (STL) format. Three experimental materials, a dental cast, occlusal bite, and bite tray impression, were optically scanned in 3D. STL files converted from the CBCT of the Typodont model and the 3D optical-scanned STL files of the study materials were image-registered. The error range of each methodology was measured and compared with a 3D optical scan of the Typodont. For the three materials, the smallest error observed was 0.099±0.114mm (mean error±standard deviation) for registering the 3D optical scan image of the dental cast onto the CBCT dental image. Although producing a dental cast can be laborious, the study results indicate that it is the preferred method. In addition, an occlusal bite is recommended when bite impression materials are used. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Recording and reading of information on optical disks

NASA Astrophysics Data System (ADS)

Bouwhuis, G.; Braat, J. J. M.

In the storage of information, related to video programs, in a spiral track on a disk, difficulties arise because the bandwidth for video is much greater than for audio signals. An attractive solution was found in optical storage. The optical noncontact method is free of wear, and allows for fast random access. Initial problems regarding a suitable light source could be overcome with the aid of appropriate laser devices. The basic concepts of optical storage on disks are treated insofar as they are relevant for the optical arrangement. A general description is provided of a video, a digital audio, and a data storage system. Scanning spot microscopy for recording and reading of optical disks is discussed, giving attention to recording of the signal, the readout of optical disks, the readout of digitally encoded signals, and cross talk. Tracking systems are also considered, taking into account the generation of error signals for radial tracking and the generation of focus error signals.

Micrometric precision of prosthetic dental crowns obtained by optical scanning and computer-aided designing/computer-aided manufacturing system

NASA Astrophysics Data System (ADS)

das Neves, Flávio Domingues; de Almeida Prado Naves Carneiro, Thiago; do Prado, Célio Jesus; Prudente, Marcel Santana; Zancopé, Karla; Davi, Letícia Resende; Mendonça, Gustavo; Soares, Carlos José

2014-08-01

The current study evaluated prosthetic dental crowns obtained by optical scanning and a computer-aided designing/computer-aided manufacturing system using micro-computed tomography to compare the marginal fit. The virtual models were obtained with four different scanning surfaces: typodont (T), regular impressions (RI), master casts (MC), and powdered master casts (PMC). Five virtual models were obtained for each group. For each model, a crown was designed on the software and milled from feldspathic ceramic blocks. Micro-CT images were obtained for marginal gap measurements and the data were statistically analyzed by one-way analysis of variance followed by Tukey's test. The mean vertical misfit was T=62.6±65.2 μm; MC=60.4±38.4 μm; PMC=58.1±38.0 μm, and RI=89.8±62.8 μm. Considering a percentage of vertical marginal gap of up to 75 μm, the results were T=71.5%, RI=49.2%, MC=69.6%, and PMC=71.2%. The percentages of horizontal overextension were T=8.5%, RI=0%, MC=0.8%, and PMC=3.8%. Based on the results, virtual model acquisition by scanning the typodont (simulated mouth) or MC, with or without powder, showed acceptable values for the marginal gap. The higher result of marginal gap of the RI group suggests that it is preferable to scan this directly from the mouth or from MC.

Optical sectioning microscopes with no moving parts using a micro-stripe array light emitting diode.

PubMed

Poher, V; Zhang, H X; Kennedy, G T; Griffin, C; Oddos, S; Gu, E; Elson, D S; Girkin, M; French, P M W; Dawson, M D; Neil, M A

2007-09-03

We describe an optical sectioning microscopy system with no moving parts based on a micro-structured stripe-array light emitting diode (LED). By projecting arbitrary line or grid patterns onto the object, we are able to implement a variety of optical sectioning microscopy techniques such as grid-projection structured illumination and line scanning confocal microscopy, switching from one imaging technique to another without modifying the microscope setup. The micro-structured LED and driver are detailed and depth discrimination capabilities are measured and calculated.

Optical benchmarking of security document readers for automated border control

NASA Astrophysics Data System (ADS)

Valentín, Kristián.; Wild, Peter; Å tolc, Svorad; Daubner, Franz; Clabian, Markus

2016-10-01

Authentication and optical verification of travel documents upon crossing borders is of utmost importance for national security. Understanding the workflow and different approaches to ICAO 9303 travel document scanning in passport readers, as well as highlighting normalization issues and designing new methods to achieve better harmonization across inspection devices are key steps for the development of more effective and efficient next- generation passport inspection. This paper presents a survey of state-of-the-art document inspection systems, showcasing results of a document reader challenge investigating 9 devices with regards to optical characteristics.

Optical Detection of Blade Flutter

NASA Technical Reports Server (NTRS)

Nieberding, W. C.; Pollack, J. L.

1977-01-01

Dynamic strain gages mounted on rotor blades are used as the primary instrumentation for detecting the onset of flutter and defining the vibratory mode and frequency. Optical devices are evaluated for performing the same measurements as well as providing supplementary information on the vibratory characteristics. Two separate methods are studied: stroboscopic imagery of the blade tip and photoelectric scanning of blade tip motion. Both methods give visual data in real time as well as video tape records. The optical systems are described, and representative results are presented. The potential of this instrumentation in flutter research is discussed.

Multispectral scanner optical system

NASA Technical Reports Server (NTRS)

Stokes, R. C.; Koch, N. G. (Inventor)

1980-01-01

An optical system for use in a multispectral scanner of the type used in video imaging devices is disclosed. Electromagnetic radiation reflected by a rotating scan mirror is focused by a concave primary telescope mirror and collimated by a second concave mirror. The collimated beam is split by a dichroic filter which transmits radiant energy in the infrared spectrum and reflects visible and near infrared energy. The long wavelength beam is filtered and focused on an infrared detector positioned in a cryogenic environment. The short wavelength beam is dispersed by a pair of prisms, then projected on an array of detectors also mounted in a cryogenic environment and oriented at an angle relative to the optical path of the dispersed short wavelength beam.