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Sample records for optical quadrature microscope

  1. Wave-Based Inversion & Imaging for the Optical Quadrature Microscope

    SciTech Connect

    Lehman, S K

    2005-10-27

    The Center for Subsurface Sensing & Imaging System's (CenSSIS) Optical Quadrature Microscope (OQM) is a narrow band visible light microscope capable of measuring both amplitude and phase of a scattered field. We develop a diffraction tomography, that is, wave-based, scattered field inversion and imaging algorithm, for reconstructing the refractive index of the scattering object.

  2. Automatic quadrature control and measuring system. [using optical coupling circuitry

    NASA Technical Reports Server (NTRS)

    Hamlet, J. F. (Inventor)

    1974-01-01

    A quadrature component cancellation and measuring system comprising a detection system for detecting the quadrature component from a primary signal, including reference circuitry to define the phase of the quadrature component for detection is described. A Raysistor optical coupling control device connects an output from the detection system to a circuit driven by a signal based upon the primary signal. Combining circuitry connects the primary signal and the circuit controlled by the Raysistor device to subtract quadrature components. A known current through the optically sensitive element produces a signal defining the magnitude of the quadrature component.

  3. 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.

  4. Solid state optical microscope

    DOEpatents

    Young, I.T.

    1983-08-09

    A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal. 2 figs.

  5. Solid state optical microscope

    DOEpatents

    Young, Ian T.

    1983-01-01

    A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal.

  6. Modeling of optical quadrature microscopy for imaging mouse embryos

    NASA Astrophysics Data System (ADS)

    Warger, William C., II; DiMarzio, Charles A.

    2008-02-01

    Optical quadrature microscopy (OQM) has been shown to provide the optical path difference through a mouse embryo, and has led to a novel method to count the total number of cells further into development than current non-toxic imaging techniques used in the clinic. The cell counting method has the potential to provide an additional quantitative viability marker for blastocyst transfer during in vitro fertilization. OQM uses a 633 nm laser within a modified Mach-Zehnder interferometer configuration to measure the amplitude and phase of the signal beam that travels through the embryo. Four cameras preceded by multiple beamsplitters record the four interferograms that are used within a reconstruction algorithm to produce an image of the complex electric field amplitude. Here we present a model for the electric field through the primary optical components in the imaging configuration and the reconstruction algorithm to calculate the signal to noise ratio when imaging mouse embryos. The model includes magnitude and phase errors in the individual reference and sample paths, fixed pattern noise, and noise within the laser and detectors. This analysis provides the foundation for determining the imaging limitations of OQM and the basis to optimize the cell counting method in order to introduce additional quantitative viability markers.

  7. Anisotropic contrast optical microscope

    NASA Astrophysics Data System (ADS)

    Peev, D.; Hofmann, T.; Kananizadeh, N.; Beeram, S.; Rodriguez, E.; Wimer, S.; Rodenhausen, K. B.; Herzinger, C. M.; Kasputis, T.; Pfaunmiller, E.; Nguyen, A.; Korlacki, R.; Pannier, A.; Li, Y.; Schubert, E.; Hage, D.; Schubert, M.

    2016-11-01

    An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent, or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. Direct generalized ellipsometry data analysis approaches permit extraction of fundamental Mueller matrix object plane images dispensing with the need of Fourier expansion methods. Generalized ellipsometry model approaches are used for quantitative image analyses. These images are obtained from sets of multiple images obtained under various polarizer, analyzer, and compensator settings. Up to 16 independent Mueller matrix images can be obtained, while our current setup is limited to 11 images normalized by the unpolarized intensity. We demonstrate the anisotropic contrast optical microscope by measuring lithographically defined micro-patterned anisotropic filters, and we quantify the adsorption of an organic self-assembled monolayer film onto the anisotropic filter. Comparison with an isotropic glass slide demonstrates the image enhancement obtained by our method over microscopy without the use of an anisotropic filter. In our current instrument, we estimate the limit of detection for organic volumetric mass within the object plane of ≈49 fg within ≈7 × 7 μm2 object surface area. Compared to a quartz crystal microbalance with dissipation instrumentation, where contemporary limits require a total load of ≈500 pg for detection, the instrumentation demonstrated here improves

  8. Anisotropic contrast optical microscope.

    PubMed

    Peev, D; Hofmann, T; Kananizadeh, N; Beeram, S; Rodriguez, E; Wimer, S; Rodenhausen, K B; Herzinger, C M; Kasputis, T; Pfaunmiller, E; Nguyen, A; Korlacki, R; Pannier, A; Li, Y; Schubert, E; Hage, D; Schubert, M

    2016-11-01

    An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent, or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. Direct generalized ellipsometry data analysis approaches permit extraction of fundamental Mueller matrix object plane images dispensing with the need of Fourier expansion methods. Generalized ellipsometry model approaches are used for quantitative image analyses. These images are obtained from sets of multiple images obtained under various polarizer, analyzer, and compensator settings. Up to 16 independent Mueller matrix images can be obtained, while our current setup is limited to 11 images normalized by the unpolarized intensity. We demonstrate the anisotropic contrast optical microscope by measuring lithographically defined micro-patterned anisotropic filters, and we quantify the adsorption of an organic self-assembled monolayer film onto the anisotropic filter. Comparison with an isotropic glass slide demonstrates the image enhancement obtained by our method over microscopy without the use of an anisotropic filter. In our current instrument, we estimate the limit of detection for organic volumetric mass within the object plane of ≈49 fg within ≈7 × 7 μm(2) object surface area. Compared to a quartz crystal microbalance with dissipation instrumentation, where contemporary limits require a total load of ≈500 pg for detection, the instrumentation demonstrated here improves

  9. Accurate cell counts in live mouse embryos using optical quadrature and differential interference contrast microscopy

    NASA Astrophysics Data System (ADS)

    Warger, William C., II; Newmark, Judith A.; Zhao, Bing; Warner, Carol M.; DiMarzio, Charles A.

    2006-02-01

    Present imaging techniques used in in vitro fertilization (IVF) clinics are unable to produce accurate cell counts in developing embryos past the eight-cell stage. We have developed a method that has produced accurate cell counts in live mouse embryos ranging from 13-25 cells by combining Differential Interference Contrast (DIC) and Optical Quadrature Microscopy. Optical Quadrature Microscopy is an interferometric imaging modality that measures the amplitude and phase of the signal beam that travels through the embryo. The phase is transformed into an image of optical path length difference, which is used to determine the maximum optical path length deviation of a single cell. DIC microscopy gives distinct cell boundaries for cells within the focal plane when other cells do not lie in the path to the objective. Fitting an ellipse to the boundary of a single cell in the DIC image and combining it with the maximum optical path length deviation of a single cell creates an ellipsoidal model cell of optical path length deviation. Subtracting the model cell from the Optical Quadrature image will either show the optical path length deviation of the culture medium or reveal another cell underneath. Once all the boundaries are used in the DIC image, the subtracted Optical Quadrature image is analyzed to determine the cell boundaries of the remaining cells. The final cell count is produced when no more cells can be subtracted. We have produced exact cell counts on 5 samples, which have been validated by Epi-Fluorescence images of Hoechst stained nuclei.

  10. Statistical reconstruction of optical quantum states based on mutually complementary quadrature quantum measurements

    SciTech Connect

    Bogdanov, Yu. I. Avosopyants, G. V.; Belinskii, L. V.; Katamadze, K. G.; Kulik, S. P.; Lukichev, V. F.

    2016-08-15

    We describe a new method for reconstructing the quantum state of the electromagnetic field from the results of mutually complementary optical quadrature measurements. This method is based on the root approach and displaces squeezed Fock states are used as the basis. Theoretical analysis and numerical experiments demonstrate the considerable advantage of the developed tools over those described in the literature.

  11. Achromatic registration of quadrature components of the optical spectrum in spectral domain optical coherence tomography

    SciTech Connect

    Shilyagin, P A; Gelikonov, G V; Gelikonov, V M; Moiseev, A A; Terpelov, D A

    2014-07-31

    We have thoroughly investigated the method of simultaneous reception of spectral components with the achromatised quadrature phase shift between two portions of a reference wave, designed for the effective suppression of the 'mirror' artefact in the resulting image obtained by means of spectral domain optical coherence tomography (SD OCT). We have developed and experimentally tested a phase-shifting element consisting of a beam divider, which splits the reference optical beam into the two beams, and of delay lines being individual for each beam, which create a mutual phase difference of π/2 in the double pass of the reference beam. The phase shift achromatism over a wide spectral range is achieved by using in the delay lines the individual elements with different dispersion characteristics. The ranges of admissible adjustment parameters of the achromatised delay line are estimated for exact and inexact conformity of the geometric characteristics of its components to those calculated. A possibility of simultaneous recording of the close-to-quadrature spectral components with a single linear photodetector element is experimentally confirmed. The suppression of the artefact mirror peak in the OCT-signal by an additional 9 dB relative to the level of its suppression is experimentally achieved when the air delay line is used. Two-dimensional images of the surface positioned at an angle to the axis of the probe beam are obtained with the correction of the 'mirror' artefact while maintaining the dynamic range of the image. (laser biophotonics)

  12. Noise tolerance in optical waveguide circuits for recognition of optical 16 quadrature amplitude modulation codes

    NASA Astrophysics Data System (ADS)

    Inoshita, Kensuke; Hama, Yoshimitsu; Kishikawa, Hiroki; Goto, Nobuo

    2016-12-01

    In photonic label routers, various optical signal processing functions are required; these include optical label extraction, recognition of the label, optical switching and buffering controlled by signals based on the label information and network routing tables, and label rewriting. Among these functions, we focus on photonic label recognition. We have proposed two kinds of optical waveguide circuits to recognize 16 quadrature amplitude modulation codes, i.e., recognition from the minimum output port and from the maximum output port. The recognition function was theoretically analyzed and numerically simulated by finite-difference beam-propagation method. We discuss noise tolerance in the circuit and show numerically simulated results to evaluate bit-error-rate (BER) characteristics against optical signal-to-noise ratio (OSNR). The OSNR required to obtain a BER less than 1.0×10-3 for the symbol rate of 2.5 GBaud was 14.5 and 27.0 dB for recognition from the minimum and maximum output, respectively.

  13. Optimization of displacement-measuring quadrature interferometers considering the real properties of optical components

    SciTech Connect

    Pozar, Tomaz; Gregorcic, Peter; Mozina, Janez

    2011-03-20

    We present the influence of alignment and the real properties of optical components on the performance of a two-detector homodyne displacement-measuring quadrature laser interferometer. An experimental method, based on the optimization of visibility and sensitivity, was established and theoretically described to assess the performance and stability of the interferometer. We show that the optimal performance of such interferometers is achieved with the iterative alignment procedure described.

  14. Optimization of displacement-measuring quadrature interferometers considering the real properties of optical components.

    PubMed

    Požar, Tomaž; Gregorčič, Peter; Možina, Janez

    2011-03-20

    We present the influence of alignment and the real properties of optical components on the performance of a two-detector homodyne displacement-measuring quadrature laser interferometer. An experimental method, based on the optimization of visibility and sensitivity, was established and theoretically described to assess the performance and stability of the interferometer. We show that the optimal performance of such interferometers is achieved with the iterative alignment procedure described.

  15. Solid-state optical microscope

    DOEpatents

    Young, I.T.

    1981-01-07

    A solid state optical microscope is described wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. Means for scanning in one of two orthogonal directions are provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal.

  16. Optical Analysis of Microscope Images

    NASA Astrophysics Data System (ADS)

    Biles, Jonathan R.

    Microscope images were analyzed with coherent and incoherent light using analog optical techniques. These techniques were found to be useful for analyzing large numbers of nonsymbolic, statistical microscope images. In the first part phase coherent transparencies having 20-100 human multiple myeloma nuclei were simultaneously photographed at 100 power magnification using high resolution holographic film developed to high contrast. An optical transform was obtained by focussing the laser onto each nuclear image and allowing the diffracted light to propagate onto a one dimensional photosensor array. This method reduced the data to the position of the first two intensity minima and the intensity of successive maxima. These values were utilized to estimate the four most important cancer detection clues of nuclear size, shape, darkness, and chromatin texture. In the second part, the geometric and holographic methods of phase incoherent optical processing were investigated for pattern recognition of real-time, diffuse microscope images. The theory and implementation of these processors was discussed in view of their mutual problems of dimness, image bias, and detector resolution. The dimness problem was solved by either using a holographic correlator or a speckle free laser microscope. The latter was built using a spinning tilted mirror which caused the speckle to change so quickly that it averaged out during the exposure. To solve the bias problem low image bias templates were generated by four techniques: microphotography of samples, creation of typical shapes by computer graphics editor, transmission holography of photoplates of samples, and by spatially coherent color image bias removal. The first of these templates was used to perform correlations with bacteria images. The aperture bias was successfully removed from the correlation with a video frame subtractor. To overcome the limited detector resolution it is necessary to discover some analog nonlinear intensity

  17. Quadrature demodulation with synchronous difference for interferometric fiber-optic gyroscopes.

    PubMed

    Wang, Zinan; Yang, Yi; Li, Yongxiao; Yu, Xiaoqi; Zhang, Zhenrong; Li, Zhengbin

    2012-11-05

    We propose a novel method of quadrature demodulation with synchronous difference for suppressing noise in interferometric fiber-optic gyroscopes (IFOGs). For an IFOG with sine wave phase modulation, an in-phase result and a quadrature result are obtained simultaneously by coherent detection. Eigenfrequency modulation is used and a phase shift of 45° is set between the modulation signal and the reference signal, so that two results have the same expectation of amplitude but with opposite signs. A synchronous difference procedure is carried out for output, in which signals are added up and common noise between two results is eliminated. Theoretical analysis and experimental results show that both short term noise and long term instability of the IFOG are reduced by this method. In experimental comparison with the traditional demodulation method on the same IFOG with a 1982 m fiber coil, this method reduces the bias drift from 0.040°/h to 0.004°/h.

  18. Improving noiseless linear amplification for optical quantum communication with quadrature squeezing

    NASA Astrophysics Data System (ADS)

    Yang, Song; Zhang, ShengLi; Zou, XuBo; Bi, SiWen; Lin, XuLing

    2013-02-01

    Quantum noiseless linear amplification (NLA) is an important tool for long-distance optical quantum communication. In this paper, we show that NLA with linear optics and photon counts can be further improved by applying quadrature squeezing. Moreover, we find that such enhancement through squeezing can be observed even when a photon dichotic on-off detector and a pseudo-single-photon state are applied to the amplification process. Such a result could find more applications in already-known NLA-related quantum information tasks.

  19. Coherent Detection of Optical Quadrature Phase-Shift Keying Signals With Carrier Phase Estimation

    NASA Astrophysics Data System (ADS)

    Ly-Gagnon, Dany-Sebastien; Tsukamoto, Satoshi; Katoh, Kazuhiro; Kikuchi, Kazuro

    2006-01-01

    This paper describes a coherent optical receiver for demodulating optical quadrature phase-shift keying (QPSK) signals. At the receiver, a phase-diversity homodyne detection scheme is employed without locking the phase of the local oscillator (LO). To handle the carrier phase drift, the carrier phase is estimated with digital signal processing (DSP) on the homodyne-detected signal. Such a scheme presents the following major advantages over the conventional optical differential detection. First, its bit error rate (BER) performance is better than that of differential detection. This higher sensitivity can extend the reach of unrepeated transmission systems and reduce crosstalk between multiwavelength channels. Second, the optoelectronic conversion process is linear, so that the whole optical signal information can be postprocessed in the electrical domain. Third, this scheme is applicable to multilevel modulation formats such as M-array PSK and quadrature amplitude modulation (QAM). The performance of the receiver is evaluated through various simulations and experiments. As a result, an unrepeated transmission over 210 km with a 20-Gb/s optical QPSK signal is achieved. Moreover, in wavelength-division multiplexing (WDM) environment, coherent detection allows the filtering of a desired wavelength channel to reside entirely in the electrical domain, taking advantage of the sharp cutoff characteristics of electrical filters. The experiments show the feasibility to transmit polarization-multiplexed 40-Gb/s QPSK signals over 200 km with channel spacing of 16 GHz, leading to a spectral efficiency as high as 2.5 b/s/Hz.

  20. Noncritical quadrature squeezing in two-transverse-mode optical parametric oscillators

    SciTech Connect

    Navarrete-Benlloch, Carlos; Roldan, Eugenio; Valcarcel, German J. de; Romanelli, Alejandro

    2010-04-15

    In this article we explore the quantum properties of a degenerate optical parametric oscillator when it is tuned to the first family of transverse modes at the down-converted frequency. Recently we found [C. Navarrete-Benlloch et al., Phys. Rev. Lett. 100, 203601 (2008)] that above threshold a TEM{sub 10} mode following a random rotation in the transverse plane emerges in this system (we denote it as the bright mode), breaking thus its rotational invariance. Then, owing to the mode orientation being undetermined, we showed that the phase quadrature of the transverse mode orthogonal to this one (denoted as the dark mode) is perfectly squeezed at any pump level and without an increase in the fluctuations on its amplitude quadrature (which seems to contradict the uncertainty principle). In this article we go further in the study of this system and analyze some important features not considered previously. First we show that the apparent violation of the uncertainty principle is just that -'apparent' - as the conjugate pair of the squeezed quadrature is not another quadrature but the orientation of the bright mode (which is completely undetermined in the long term). We also study a homodyne scheme in which the local oscillator is not perfectly matched to the dark mode, as this could be impossible in real experiments due to the random rotation of the mode, showing that even in this case large levels of noise reduction can be obtained (also including the experimentally unavoidable phase fluctuations). Finally, we show that neither the adiabatic elimination of the pump variables nor the linearization of the quantum equations are responsible for the remarkable properties of the dark mode (which we prove analytically and through numerical simulations, respectively), which were simplifying assumptions used in Navarrete-Benlloch et al. [Phys. Rev. Lett. 100, 203601 (2008)]. These studies show that the production of noncritically squeezed light through spontaneous rotational

  1. Compressive optical image encryption with two-step-only quadrature phase-shifting digital holography

    NASA Astrophysics Data System (ADS)

    Li, Jun; Li, Hongbing; Li, Jiaosheng; Pan, Yangyang; Li, Rong

    2015-06-01

    An image encryption method which combines two-step-only quadrature phase-shifting digital holography with compressive sensing (CS) has been proposed in the fully optical domain. An object image is firstly encrypted to two on-axis quadrature-phase holograms using the two random phase masks in the Mach-Zehnder interferometer. Then, the two encrypted images are highly compressed to a one-dimensional signal using the single-pixel compressive holographic imaging in the optical domain. At the receiving terminal, the two compressive encrypted holograms are exactly reconstructed from much less than the Nyquist sampling number of observations by solving an optimization problem, and the original image can be decrypted with only two reconstructed holograms and the correct keys. This method largely decreases holograms data volume for the current optical image encryption system, and it is also suitable for some special optical imaging cases such as different wavelengths imaging and weak light imaging. Numerical simulation is performed to demonstrate the feasibility and validity of this novel image encryption method.

  2. 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

  3. Enhanced 16 Spiral quadrature amplitude modulation scheme for coherent optical orthogonal frequency division multiplexing systems

    NASA Astrophysics Data System (ADS)

    He, Jing; Li, Chong; Chen, Lin; Chen, Ming

    2014-09-01

    We propose an enhanced 16 Spiral quadrature amplitude modulation (QAM) (16 E-Spiral QAM) scheme to overcome the laser phase noise in a coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. Considering both additive white Gaussian noise and large phase noise, 16 E-Spiral QAM schemes have a better transmission performance compared to conventional 16 QAM CO-OFDM systems. The simulated results show that the required optical signal-to-noise ratio (OSNR) of the proposed 16 QAM is, respectively, 0.8 and 2.3 dB less than 16 Spiral and conventional 16 QAM at a bit error rate (BER) of 10-3 in a back-to-back case. After 800-km transmission over a single-mode fiber, the tolerance for the laser linewidth of the 16 E-Spiral QAM can improve about 30 kHz with an OSNR of 18 dB compared to that of a conventional 16 QAM.

  4. Optical torque on microscopic objects.

    PubMed

    Parkin, Simon; Knöner, Gregor; Singer, Wolfgang; Nieminen, Timo A; Heckenberg, Norman R; Rubinsztein-Dunlop, Halina

    2007-01-01

    We outline in general the role and potential areas of application for the use of optical torque in optical tweezers. Optically induced torque is always a result of transfer of angular momentum from light to a particle with conservation of momentum as an underlying principle. Consequently, rotation can be induced by a beam of light that carries angular momentum (AM) or by a beam that carries no AM but where AM is induced in the beam by the particle. First, we analyze some techniques to exert torque with optical tweezers such as dual beam traps. We also discuss the alignment and rotation which is achieved using laser beams carrying intrinsic AM-either spin or orbital AM, or both. We then discuss the types of particles that can be trapped and rotated in such beams such as absorbing or birefringent particles. We present a systematic study of the alignment of particles with respect to the beam axis and the beam's polarization as a way of inducing optical torque by studying crystals of the protein lysozyme. We present the theory behind quantitative measurements of both spin and orbital momentum transfer. Finally, we discuss the applications of rotation in optically driven micromachines, microrheology, flow field measurements, and microfluidics.

  5. Accurate phase measurements for thick spherical objects using optical quadrature microscopy

    NASA Astrophysics Data System (ADS)

    Warger, William C., II; DiMarzio, Charles A.

    2009-02-01

    In vitro fertilization (IVF) procedures have resulted in the birth of over three million babies since 1978. Yet the live birth rate in the United States was only 34% in 2005, with 32% of the successful pregnancies resulting in multiple births. These multiple pregnancies were directly attributed to the transfer of multiple embryos to increase the probability that a single, healthy embryo was included. Current viability markers used for IVF, such as the cell number, symmetry, size, and fragmentation, are analyzed qualitatively with differential interference contrast (DIC) microscopy. However, this method is not ideal for quantitative measures beyond the 8-cell stage of development because the cells overlap and obstruct the view within and below the cluster of cells. We have developed the phase-subtraction cell-counting method that uses the combination of DIC and optical quadrature microscopy (OQM) to count the number of cells accurately in live mouse embryos beyond the 8-cell stage. We have also created a preliminary analysis to measure the cell symmetry, size, and fragmentation quantitatively by analyzing the relative dry mass from the OQM image in conjunction with the phase-subtraction count. In this paper, we will discuss the characterization of OQM with respect to measuring the phase accurately for spherical samples that are much larger than the depth of field. Once fully characterized and verified with human embryos, this methodology could provide the means for a more accurate method to score embryo viability.

  6. 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.

  7. Shaped offset quadrature phase shift keying (SOQPSK) modulation scheme and its application in optical wavelength-division multiplexed (DWDM) transmission

    NASA Astrophysics Data System (ADS)

    Zou, Ning; Huang, Benxiong; Xu, Zhengguang

    2013-10-01

    This paper presents a new quaternary modulation scheme called SOQPSK. The principle on the optical SOQPSK generation is derived and analyzed, which is implemented by traditional Mach-Zehnder modulators. The performance of the optical SOQPSK modulated system is evaluated and compared with those of quadrature phase shift keying (QPSK) and offset QPSK (OQPSK) modulation systems via simulation, in terms of spectral efficiency, receiver sensitivity and density DWDM transmission performance. Simulations show that the novel modulation scheme improves spectral efficiency for DWDM transmission and provides better transmission performance than QPSK.

  8. The optics of microscope image formation.

    PubMed

    Wolf, David E

    2013-01-01

    Although geometric optics gives a good understanding of how the microscope works, it fails in one critical area, which is explaining the origin of microscope resolution. To accomplish this, one must consider the microscope from the viewpoint of physical optics. This chapter describes the theory of the microscope-relating resolution to the highest spatial frequency that a microscope can collect. The chapter illustrates how Huygens' principle or construction can be used to explain the propagation of a plane wave. It is shown that this limit increases with increasing numerical aperture (NA). As a corollary to this, resolution increases with decreasing wavelength because of how NA depends on wavelength. The resolution is higher for blue light than red light. Resolution is dependent on contrast, and the higher the contrast, the higher the resolution. This last point relates to issues of signal-to-noise and dynamic range. The use of video and new digital cameras has necessitated redefining classical limits such as those of Rayleigh's criterion.

  9. Optics of high-performance electron microscopes*

    PubMed Central

    Rose, H H

    2008-01-01

    During recent years, the theory of charged particle optics together with advances in fabrication tolerances and experimental techniques has lead to very significant advances in high-performance electron microscopes. Here, we will describe which theoretical tools, inventions and designs have driven this development. We cover the basic theory of higher-order electron optics and of image formation in electron microscopes. This leads to a description of different methods to correct aberrations by multipole fields and to a discussion of the most advanced design that take advantage of these techniques. The theory of electron mirrors is developed and it is shown how this can be used to correct aberrations and to design energy filters. Finally, different types of energy filters are described. PMID:27877933

  10. Optics of high-performance electron microscopes.

    PubMed

    Rose, H H

    2008-01-01

    During recent years, the theory of charged particle optics together with advances in fabrication tolerances and experimental techniques has lead to very significant advances in high-performance electron microscopes. Here, we will describe which theoretical tools, inventions and designs have driven this development. We cover the basic theory of higher-order electron optics and of image formation in electron microscopes. This leads to a description of different methods to correct aberrations by multipole fields and to a discussion of the most advanced design that take advantage of these techniques. The theory of electron mirrors is developed and it is shown how this can be used to correct aberrations and to design energy filters. Finally, different types of energy filters are described.

  11. Optical modeling of Fresnel zoneplate microscopes

    SciTech Connect

    Naulleau, Patrick; Mochi, Iacopo; Goldberg, Kenneth A.

    2011-04-06

    Defect free masks remain one of the most significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. Progress on this front requires high-performance wavelength-specific metrology of EUV masks, including high-resolution and aerial-image microscopy performed near the 13.5 nm wavelength. Arguably the most cost-effective and rapid path to proliferating this capability is through the development of Fresnel zoneplate-based microscopes. Given the relative obscurity of such systems, however, modeling tools are not necessarily optimized to deal with them and their imaging properties are poorly understood. Here we present a modeling methodology to analyze zoneplate microscopes based on commercially available optical modeling software and use the technique to investigate the imaging performance of an off-axis EUV microscope design. The modeling predicts that superior performance can be achieved by tilting the zoneplate, making it perpendicular to the chief ray at the center of the field, while designing the zoneplate to explicitly work in that tilted plane. Although the examples presented here are in the realm of EUV mask inspection, the methods described and analysis results are broadly applicable to zoneplate microscopes in general, including full-field soft-x-ray microscopes rou tinely used in the synchrotron community.

  12. Optical modeling of Fresnel zoneplate microscopes.

    PubMed

    Naulleau, Patrick P; Mochi, Iacopo; Goldberg, Kenneth A

    2011-07-10

    Defect free masks remain one of the most significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. Progress on this front requires high-performance wavelength-specific metrology of EUV masks, including high-resolution and aerial-image microscopy performed near the 13.5 nm wavelength. Arguably the most cost-effective and rapid path to proliferating this capability is through the development of Fresnel zoneplate-based microscopes. Given the relative obscurity of such systems, however, modeling tools are not necessarily optimized to deal with them and their imaging properties are poorly understood. Here we present a modeling methodology to analyze zoneplate microscopes based on commercially available optical modeling software and use the technique to investigate the imaging performance of an off-axis EUV microscope design. The modeling predicts that superior performance can be achieved by tilting the zoneplate, making it perpendicular to the chief ray at the center of the field, while designing the zoneplate to explicitly work in that tilted plane. Although the examples presented here are in the realm of EUV mask inspection, the methods described and analysis results are broadly applicable to zoneplate microscopes in general, including full-field soft-x-ray microscopes routinely used in the synchrotron community.

  13. Optical modeling of Fresnel zoneplate microscopes

    SciTech Connect

    Naulleau, Patrick P.; Mochi, Iacopo; Goldberg, Kenneth A.

    2011-07-10

    Defect free masks remain one of the most significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. Progress on this front requires high-performance wavelength-specific metrology of EUV masks, including high-resolution and aerial-image microscopy performed near the 13.5 nm wavelength. Arguably the most cost-effective and rapid path to proliferating this capability is through the development of Fresnel zoneplate-based microscopes. Given the relative obscurity of such systems, however, modeling tools are not necessarily optimized to deal with them and their imaging properties are poorly understood. Here we present a modeling methodology to analyze zoneplate microscopes based on commercially available optical modeling software and use the technique to investigate the imaging performance of an off-axis EUV microscope design. The modeling predicts that superior performance can be achieved by tilting the zoneplate, making it perpendicular to the chief ray at the center of the field, while designing the zoneplate to explicitly work in that tilted plane. Although the examples presented here are in the realm of EUV mask inspection, the methods described and analysis results are broadly applicable to zoneplate microscopes in general, including full-field soft-x-ray microscopes routinely used in the synchrotron community.

  14. Microscopic optical buffering in a harmonic potential

    PubMed Central

    Sumetsky, M.

    2015-01-01

    In the early days of quantum mechanics, Schrödinger noticed that oscillations of a wave packet in a one-dimensional harmonic potential well are periodic and, in contrast to those in anharmonic potential wells, do not experience distortion over time. This original idea did not find applications up to now since an exact one-dimensional harmonic resonator does not exist in nature and has not been created artificially. However, an optical pulse propagating in a bottle microresonator (a dielectric cylinder with a nanoscale-high bump of the effective radius) can exactly imitate a quantum wave packet in the harmonic potential. Here, we propose a tuneable microresonator that can trap an optical pulse completely, hold it as long as the material losses permit, and release it without distortion. This result suggests the solution of the long standing problem of creating a microscopic optical buffer, the key element of the future optical signal processing devices. PMID:26689546

  15. Optical encryption of parallel quadrature phase shift keying signals based on nondegenerate four-wave mixing in highly nonlinear fiber

    NASA Astrophysics Data System (ADS)

    Cui, Yue; Zhang, Min; Zhan, Yueying; Wang, Danshi; Huang, Shanguo

    2016-08-01

    A scheme for optical parallel encryption/decryption of quadrature phase shift keying (QPSK) signals is proposed, in which three QPSK signals at 10 Gb/s are encrypted and decrypted simultaneously in the optical domain through nondegenerate four-wave mixing in a highly nonlinear fiber. The results of theoretical analysis and simulations show that the scheme can perform high-speed wiretapping against the encryption of parallel signals and receiver sensitivities of encrypted signal and the decrypted signal are -25.9 and -23.8 dBm, respectively, at the forward error correction threshold. The results are useful for designing high-speed encryption/decryption of advanced modulated signals and thus enhancing the physical layer security of optical networks.

  16. Detection and alignment of dual-polarization optical quadrature amplitude transmitter IQ and XY skews using reconfigurable interference.

    PubMed

    Yue, Yang; Zhang, Bo; Wang, Qiang; Lofland, Rob; O'Neil, Jason; Anderson, Jon

    2016-03-21

    Dual-polarization quadrature amplitude modulation (DP-QAM) is one of the feasible paths towards 100-Gb/s, 400-Gb/s and 1-Tb/s optical fiber communications systems. For DP-QAM transmitter, the time mismatch between the in-phase and quadrature (IQ) or x-polarized and y-polarized (XY) tributary channels is known as the IQ or XY skew. Large uncompensated IQ or XY skew can significantly degrade the optical fiber communications system performance. Sometimes, time-interleaved return-to-zero (RZ) DP signal is preferred with lower nonlinear polarization scattering induced penalty. In this work, detection and alignment of DP-QAM transmitter IQ and XY skews using reconfigurable interference is experimentally demonstrated. For IQ skew detection, a total dynamic range of 26.4 dB is achieved with ~1-dB power change for 0.5-ps skew from well alignment. For XY skew detection, it shows 23.2-dB dynamic range, and ~1.5-dB power change is achieved for 1-ps XY skew. Fast detection algorithm for arbitrary skew is also proposed and experimentally verified. The scheme is compatible with different modulation formats, flexible data sequences, and variable waveforms.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Spin microscope based on optically detected magnetic resonance

    SciTech Connect

    Berman, Gennady P.; Chernobrod, Boris M.

    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.

  2. Detection and alignment of XY skew for dual-polarization optical quadrature amplitude transmitter using reconfigurable interference

    NASA Astrophysics Data System (ADS)

    Yue, Yang; Zhang, Bo; Wang, Qiang; Lofland, Rob; O'Neil, Jason; Anderson, Jon

    2016-02-01

    DP-QAM is one of the feasible paths towards 100Gbps, 400Gbps and 1Tbps optical communications systems. For DPQAM transmitter, the time mismatch between the XY tributary channels is known as the XY skew. Large uncompensated XY skew can significantly degrade the system performance. Sometimes, time-interleaved return-to-zero DP signal is preferred with lower nonlinear polarization scattering induced penalty. In this work, XY skew detection and alignment of dual-polarization optical quadrature amplitude transmitter using reconfigurable interference is experimentally demonstrated with >23-dB dynamic range. ~1.5-dB power change is achieved for 1-ps XY skew. Fast detecting scheme for arbitrary skew measurement is also experimentally verified. The scheme is compatible with different modulation formats, data sequences, and waveforms.

  3. Length Scales in Bayesian Automatic Adaptive Quadrature

    NASA Astrophysics Data System (ADS)

    Adam, Gh.; Adam, S.

    2016-02-01

    Two conceptual developments in the Bayesian automatic adaptive quadrature approach to the numerical solution of one-dimensional Riemann integrals [Gh. Adam, S. Adam, Springer LNCS 7125, 1-16 (2012)] are reported. First, it is shown that the numerical quadrature which avoids the overcomputing and minimizes the hidden floating point loss of precision asks for the consideration of three classes of integration domain lengths endowed with specific quadrature sums: microscopic (trapezoidal rule), mesoscopic (Simpson rule), and macroscopic (quadrature sums of high algebraic degrees of precision). Second, sensitive diagnostic tools for the Bayesian inference on macroscopic ranges, coming from the use of Clenshaw-Curtis quadrature, are derived.

  4. Optical microscopic imaging based on VRML language

    NASA Astrophysics Data System (ADS)

    Zhang, Xuedian; Zhang, Zhenyi; Sun, Jun

    2009-11-01

    As so-called VRML (Virtual Reality Modeling Language), is a kind of language used to establish a model of the real world or a colorful world made by people. As in international standard, VRML is the main kind of program language based on the "www" net building, which is defined by ISO, the kind of MIME is x-world or x-VRML. The most important is that it has no relationship with the operating system. Otherwise, because of the birth of VRML 2.0, its ability of describing the dynamic condition gets better, and the interaction of the internet evolved too. The use of VRML will bring a revolutionary change of confocal microscope. For example, we could send different kinds of swatch in virtual 3D style to the net. On the other hand, scientists in different countries could use the same microscope in the same time to watch the same samples by the internet. The mode of sending original data in the model of text has many advantages, such as: the faster transporting, the fewer data, the more convenient updating and fewer errors. In the following words we shall discuss the basic elements of using VRML in the field of Optical Microscopic imaging.

  5. Optical and digital microscopic imaging techniques and applications in pathology.

    PubMed

    Chen, Xiaodong; Zheng, Bin; Liu, Hong

    2011-01-01

    The conventional optical microscope has been the primary tool in assisting pathological examinations. The modern digital pathology combines the power of microscopy, electronic detection, and computerized analysis. It enables cellular-, molecular-, and genetic-imaging at high efficiency and accuracy to facilitate clinical screening and diagnosis. This paper first reviews the fundamental concepts of microscopic imaging and introduces the technical features and associated clinical applications of optical microscopes, electron microscopes, scanning tunnel microscopes, and fluorescence microscopes. The interface of microscopy with digital image acquisition methods is discussed. The recent developments and future perspectives of contemporary microscopic imaging techniques such as three-dimensional and in vivo imaging are analyzed for their clinical potentials.

  6. Phase quadrature discrimination based on three-pump four-wave mixing in nonlinear optical fibers.

    PubMed

    Baillot, Maxime; Gay, Mathilde; Peucheret, Christophe; Michel, Joindot; Chartier, Thierry

    2016-11-14

    We theoretically and experimentally study the principle of phase-sensitive frequency conversion in a highly-nonlinear fiber using three pump waves. This mechanism, originally demonstrated with four continuous-wave pumps and a signal wave, is based on four-wave mixing and enables to convert the two quadrature components of the signal to different frequencies. In this work, we derive a set of two simple equations to describe this mechanism and find analytic solutions. We show that only three pumps are required, instead of four as originally proposed. We give simple relations to determine the initial conditions for the power levels and the phases of the pumps. To validate this approach, we perform an experimental demonstration of the three-pump scheme and find excellent agreement with the theory.

  7. Noise tolerance in wavelength-selective switching of optical differential quadrature-phase-shift-keying pulse train by collinear acousto-optic devices.

    PubMed

    Goto, Nobuo; Miyazaki, Yasumitsu

    2014-06-01

    Optical switching of high-bit-rate quadrature-phase-shift-keying (QPSK) pulse trains using collinear acousto-optic (AO) devices is theoretically discussed. Since the collinear AO devices have wavelength selectivity, the switched optical pulse trains suffer from distortion when the bandwidth of the pulse train is comparable to the pass bandwidth of the AO device. As the AO device, a sidelobe-suppressed device with a tapered surface-acoustic-wave (SAW) waveguide and a Butterworth-type filter device with a lossy SAW directional coupler are considered. Phase distortion of optical pulse trains at 40 to 100  Gsymbols/s in QPSK format is numerically analyzed. Bit-error-rate performance with additive Gaussian noise is also evaluated by the Monte Carlo method.

  8. Optical channel de-aggregation of quadrature-phase-shift-keying and eight-phase-shift-keying data using mapping onto constellation axes.

    PubMed

    Ziyadi, Morteza; Mohajerin-Ariaei, Amirhossein; Almaiman, Ahmed; Cao, Yinwen; Chitgarha, Mohammad Reza; Paraschis, Loukas; Tur, Moshe; Langrock, Carsten; Fejer, Martin M; Touch, Joseph D; Willner, Alan E

    2015-11-01

    An eight-phase-shift-keying signal is experimentally de-aggregated onto two four-pulse amplitude modulation signals using nonlinear processes in optical elements. Quadrature-phase-shift-keying signals are similarly de-multiplexed into two binary phase shift keying signals by mapping the data points onto the constellation axes. De-multiplexing performance is evaluated as a function of the optical signal-to-noise ratio of the incoming signals. The effect of phase noise is also studied.

  9. 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.

  10. Adaptive optical microscope for brain imaging in vivo

    NASA Astrophysics Data System (ADS)

    Wang, Kai

    2017-04-01

    The optical heterogeneity of biological tissue imposes a major limitation to acquire detailed structural and functional information deep in the biological specimens using conventional microscopes. To restore optimal imaging performance, we developed an adaptive optical microscope based on direct wavefront sensing technique. This microscope can reliably measure and correct biological samples induced aberration. We demonstrated its performance and application in structural and functional brain imaging in various animal models, including fruit fly, zebrafish and mouse.

  11. Teaching Optics to Biology Students Through Constructing a Light Microscope

    NASA Astrophysics Data System (ADS)

    Ross, Jennifer

    2015-03-01

    The microscope is familiar to many disciplines, including physics, materials science, chemistry, and the life sciences. It demonstrates fundamental aspects of ray and wave optics, making it an ideal system to help educate students in the basic concepts of optics and in measurement principles and techniques. We present an experimental system developed to teach students the basics of ray and wave optics. The students design, build, and test a light microscope made from optics components. We describe the equipment and the basic measurements that students can perform to develop experimental techniques to understand optics principles. Students measure the magnification and test the resolution of the microscope. The system is open and versatile to allow advanced projects such as epi-fluorescence, total internal reflection fluorescence, and optical trapping. We have used this equipment in an optics course, an advanced laboratory course, and graduate-level training modules.

  12. Miniature electron microscope beam column optics

    NASA Astrophysics Data System (ADS)

    Loyd, Jody Stuart

    This investigation is in the area of electrostatic lens design with the overarching goal of contributing to the creation of a miniaturized scanning electron microscope (SEM) for use in mineralogical analysis or detection of signs of life on the surface of Mars. Such an instrument could also have application in the exploration of Earth's moon, planetary moons, asteroids, or comets. Other embodiments could include tabletop or field portable SEMs for use on Earth. The scope of this research is in the design of a beam column that attains focusing, demagnification, and aberration control within the smallest achievable package. The goals of planetary exploration and of spaceflight in general impose severe constraints on the instrument's mass and electrical power consumption, while favoring a robust design of small size and high rigidity that is also simple to align. To meet these requirements a design using electrostatic lenses was favored because of the lower power requirement and mass of electrostatic versus magnetic lenses, their relatively simple construction, as well as inherently easier shielding from extraneous fields. In modeling the lens field, a hybrid of a Boundary Element Method (BEM) and a Fourier series solution was employed, whereby an initial solution from the BEM is used to derive the bounding potential of a cylindrical subdomain for the subsequent Fourier series solution. The approach is applicable to many problems in physics and combines the inherent precision of this series solution with the flexibility of BEM to describe practical, non-idealized electrode shapes. The resulting lens field in the Fourier series subdomain is of higher precision, thereby allowing smaller errors in subsequent calculations of electron ray paths. The effects of aberrations are thus easier to observe in tracing non-paraxial rays. A significant speed increase in tracing rays is also observed. The modeling technique has been validated by reproducing example ray-traces through

  13. Real-time quadrature projection complex conjugate resolved Fourier domain optical coherence tomography.

    PubMed

    Sarunic, Marinko V; Applegate, Brian E; Izatt, Joseph A

    2006-08-15

    We present a novel algorithm for full-range imaging by suppression of the complex conjugate artifact in phase-shifting Fourier domain optical coherence tomography. This technique utilizes the projection of multiple phase-shifted interferograms onto an orthogonal basis set to reconstruct the complex interferogram. Full-range imaging with >30 dB suppression of the symmetric artifact is demonstrated using a 3 x 3 fiber coupler swept source OCT system, providing a depth range of 6.6mm with -8 dB roll-off in sensitivity at the depth boundaries relative to DC. Real-time display of full-range images of the anterior segment of the human eye acquired in vivo at a line rate of 6.67 kHz are presented.

  14. X-ray-optical analytical microscope with two Kumakhov lenses

    NASA Astrophysics Data System (ADS)

    Borisov, G. I.; Kondratenko, R. I.; Odinov, B. V.; Pukhov, A. V.

    2005-07-01

    On the basis of research microscope equipped with a 3D sample stage and two x-ray micro analyzers fitted with Kumakhov polycapillary optics, an x-ray optical scanning microscope (ROCAM) has been developed. The instrument is designed for investigation ofheterogeneous objects in optic and x-ray spectra of photon radiation. Examples of ROCAM application for forensic studies and in mineralogy are shown. The instrument can be used in medicine and biology, metal studies, nuclear power, ecology, micro electronics, in customs, for investigation of pieces of art and so on.

  15. Ultrafast superresolution fluorescence imaging with spinning disk confocal microscope optics.

    PubMed

    Hayashi, Shinichi; Okada, Yasushi

    2015-05-01

    Most current superresolution (SR) microscope techniques surpass the diffraction limit at the expense of temporal resolution, compromising their applications to live-cell imaging. Here we describe a new SR fluorescence microscope based on confocal microscope optics, which we name the spinning disk superresolution microscope (SDSRM). Theoretically, the SDSRM is equivalent to a structured illumination microscope (SIM) and achieves a spatial resolution of 120 nm, double that of the diffraction limit of wide-field fluorescence microscopy. However, the SDSRM is 10 times faster than a conventional SIM because SR signals are recovered by optical demodulation through the stripe pattern of the disk. Therefore a single SR image requires only a single averaged image through the rotating disk. On the basis of this theory, we modified a commercial spinning disk confocal microscope. The improved resolution around 120 nm was confirmed with biological samples. The rapid dynamics of micro-tubules, mitochondria, lysosomes, and endosomes were observed with temporal resolutions of 30-100 frames/s. Because our method requires only small optical modifications, it will enable an easy upgrade from an existing spinning disk confocal to a SR microscope for live-cell imaging.

  16. Ultrafast superresolution fluorescence imaging with spinning disk confocal microscope optics

    PubMed Central

    Hayashi, Shinichi; Okada, Yasushi

    2015-01-01

    Most current superresolution (SR) microscope techniques surpass the diffraction limit at the expense of temporal resolution, compromising their applications to live-cell imaging. Here we describe a new SR fluorescence microscope based on confocal microscope optics, which we name the spinning disk superresolution microscope (SDSRM). Theoretically, the SDSRM is equivalent to a structured illumination microscope (SIM) and achieves a spatial resolution of 120 nm, double that of the diffraction limit of wide-field fluorescence microscopy. However, the SDSRM is 10 times faster than a conventional SIM because SR signals are recovered by optical demodulation through the stripe pattern of the disk. Therefore a single SR image requires only a single averaged image through the rotating disk. On the basis of this theory, we modified a commercial spinning disk confocal microscope. The improved resolution around 120 nm was confirmed with biological samples. The rapid dynamics of micro­tubules, mitochondria, lysosomes, and endosomes were observed with temporal resolutions of 30–100 frames/s. Because our method requires only small optical modifications, it will enable an easy upgrade from an existing spinning disk confocal to a SR microscope for live-cell imaging. PMID:25717185

  17. Optical inversions based on polarization parameters indirect microscopic imaging

    NASA Astrophysics Data System (ADS)

    Liu, Guoyan; Gao, Kun; Liu, Xuefeng; Huang, Zicheng; Ni, Guoqiang

    2016-10-01

    The resolution of conventional optical microscope is intrinsically limited by the optical diffraction, therefore it cannot be used in the measurement of sub-100nm shape and structural detection. Non-optical imaging techniques are not limited by the optical diffraction. For example, scanning tunneling microscopy (STM) and atomic force microscopy (AFM), but both of them have the weakness of narrow view field, low efficiency, and excessive cost. To detect nanoscale material, a new microscopic imaging technique is introduced in this paper, i.e. the polarization parameter indirect microscopic imaging technique. A conventional reflection microscopic system is used as the basic optical system, with polarization-modulation mechanics being inserted into it. The near-field structural characteristics can be delivered by optical wave and material coupling. According to coupling and conduction physics, changes of the optical wave parameters can be calculated, and then curves of the image intensity can be obtained. By analyzing the near-field polarization parameters in nanoscale, indirect polarization parameter imaging can be established.

  18. Collisional blockade in microscopic optical dipole traps.

    PubMed

    Schlosser, N; Reymond, G; Grangier, P

    2002-07-08

    We analyze the operating regimes of a very small optical dipole trap, loaded from a magneto-optical trap, as a function of the atom loading rate, i.e., the number of atoms per second entering the dipole trap. We show that, when the dipole trap volume is small enough, a "collisional blockade" mechanism locks the average number of trapped atoms on the value 0.5 over a large range of loading rates. We also discuss the "weak loading" and "strong loading" regimes outside the blockade range, and we demonstrate experimentally the existence of these three regimes.

  19. Near-Field Magneto-Optical Microscope

    SciTech Connect

    Vlasko-Vlasov, Vitalii; Welp, Ulrich; and Crabtree, George W.

    2005-12-06

    A device and method for mapping magnetic fields of a sample at a resolution less than the wavelength of light without altering the magnetic field of the sample is disclosed. A device having a tapered end portion with a magneto-optically active particle positioned at the distal end thereof in communication with a fiber optic for transferring incoming linearly polarized light from a source thereof to the particle and for transferring reflected light from the particle is provided. The fiber optic has a reflective material trapping light within the fiber optic and in communication with a light detector for determining the polarization of light reflected from the particle as a function of the strength and direction of the magnetic field of the sample. Linearly polarized light from the source thereof transferred to the particle positioned proximate the sample is affected by the magnetic field of the sample sensed by the particle such that the difference in polarization of light entering and leaving the particle is due to the magnetic field of the sample. Relative movement between the particle and sample enables mapping.

  20. Near Field Magneto-Optical Microscope

    DOEpatents

    Vlasko-Vlasov, Vitalii K.; Welp, Ulrich; Crabtree, George W.

    2005-12-06

    A device and method for mapping magnetic fields of a sample at a resolution less than the wavelength of light without altering the magnetic field of the sample is disclosed. A device having a tapered end portion with a magneto-optically active particle positioned at the distal end thereof in communication with a fiber optic for transferring incoming linearly polarized light from a source thereof to the particle and for transferring reflected light from the particle is provided. The fiber optic has a reflective material trapping light within the fiber optic and in communication with a light detector for determining the polarization of light reflected from the particle as a function of the strength and direction of the magnetic field of the sample. Linearly polarized light from the source thereof transferred to the particle positioned proximate the sample is affected by the magnetic field of the sample sensed by the particle such that the difference in polarization of light entering and leaving the particle is due to the magnetic field of the sample. Relative movement between the particle and sample enables mapping.

  1. Research and application of ergonomics to optical microscope

    NASA Astrophysics Data System (ADS)

    Jiang, Xue-kun; Xiao, Ze-xin; Zhang, Jie

    2008-03-01

    The characteristics of the human and the microscope, and their integrated characteristic have been studied respectively in this paper. Our results indicated that the correspondence of (i) focusing installment with human body arm, (ii) the height of ocular with eyes, (iii) visual characteristic with illuminative condition of the optical microscope, should obey the theory of the ergonomics. This was reflected in the structural design and the produce of the product, and therefore, improved the property of the amenity of the machine.

  2. Pulse-grouping transmission of optical quadrature phase-shift keying signals with time diversity multiple-input and multiple-output detection and processing

    NASA Astrophysics Data System (ADS)

    Gao, Guanjun; Chen, Sai; Zhang, Jie

    2016-08-01

    We investigate an optical pulse-overlap transmission scheme where the orthogonal condition between neighbor pulses is violated. The interferences between the grouped optical pulses are mitigated at the optical coherent receiver with time diversity multiple-input and multiple-output-based digital signal processing. Numerical simulation investigates the performance of 50% return-to-zero (RZ)-quadrature phase-shift keying (QPSK) signals, where up to four pulses are overlapped and grouped for per pulse period. In the experiment demonstration, two 50% RZ-QPSK signals are combined with different time offset between neighbor pulses, and the Q-performance as a function of optical-signal-to-noise ratio (OSNR) is compared on each pulse channel basis, with minimum OSNR penalty of only 1-dB compared to the single pulse transmission.

  3. High-resolution fiber optic confocal microscope

    NASA Astrophysics Data System (ADS)

    Ilev, Ilko K.; Waynant, Ronald W.

    2001-04-01

    A novel design of a simple reflection confocal microscope with a multimode graded-index fiber output as an effective way for improving the dynamic range of the resolving power and achieving a submicron spatial resolution is presented. The basic idea for obtaining high spatial resolution involves the following advanced scheme properties. (1) It is an apertureless confocal arrangement in which the input laser emission with its maximum power is launched directly to the test object. (2) It uses a high-numerical-aperture focusing objective (NA>0.8) that provides high depth and spatial discriminations and thus, high axial and lateral resolutions are obtained. (3) It uses a graded-index multimode fiber (50-μm-core diameter) for signal detection rather than a conventional pinhole or single-mode fiber. The graded-index fiber ensures efficient launching and maintenance of high laser powers, and high sensitivity of signal detection. Moreover, according to the equivalent-Gaussian-mode model, the intensity mode distribution into the graded-index fiber can be presented as an equivalent Gaussian mode distribution. As a result, a significant reduction of the mode noise of the intensity distribution and of signal fluctuations is obtained. Thus, a regime of high-output power is achieved that provides high resolving power and a submicron axial resolution of 0.4 μm.

  4. 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.

  5. New formalism for two-photon quantum optics. I - Quadrature phases and squeezed states. II - Mathematical foundation and compact notation

    NASA Technical Reports Server (NTRS)

    Caves, C. M.; Schumaker, B. L.

    1985-01-01

    A new formalism for analyzing two-photon devices, such as parametric amplifiers and phase-conjugate mirrors, is proposed in part I, focusing on the properties and the significance of the quadrature-phase amplitudes and two-mode squeezed states. Time-stationary quasi-probability noise is also detailed for the case of Gaussian noise, and uncertainty principles for the quadrature-phase amplitudes are outlined, as well as some important properties of the two-mode states. Part II establishes a mathematical foundation for the formalism, with introduction of a vector notation for compact representation of two-mode properties. Fundamental unitary operators and special quantum states are also examined with an emphasis on the two-mode squeezed states. The results are applied to a previously studied degenerate limit (epsilon = 0).

  6. New formalism for two-photon quantum optics. I - Quadrature phases and squeezed states. II - Mathematical foundation and compact notation

    NASA Technical Reports Server (NTRS)

    Caves, C. M.; Schumaker, B. L.

    1985-01-01

    A new formalism for analyzing two-photon devices, such as parametric amplifiers and phase-conjugate mirrors, is proposed in part I, focusing on the properties and the significance of the quadrature-phase amplitudes and two-mode squeezed states. Time-stationary quasi-probability noise is also detailed for the case of Gaussian noise, and uncertainty principles for the quadrature-phase amplitudes are outlined, as well as some important properties of the two-mode states. Part II establishes a mathematical foundation for the formalism, with introduction of a vector notation for compact representation of two-mode properties. Fundamental unitary operators and special quantum states are also examined with an emphasis on the two-mode squeezed states. The results are applied to a previously studied degenerate limit (epsilon = 0).

  7. Efficient frequency-domain channel equalization methods for dual-polarization orthogonal frequency-division multiplexing/offset quadrature amplitude modulation-passive optical network

    NASA Astrophysics Data System (ADS)

    Lin, Bangjiang; Fang, Xi; Tang, Xuan; Lin, Chun; Li, Yiwei; Zhang, Shihao; Wu, Yi; Li, Hui

    2016-10-01

    We present dual-polarization orthogonal frequency-division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) transmission for passive optical network (PON) with intensity modulation and direct detection, which has high spectral efficiency and high robustness against chromatic dispersion (CD) and polarization mode dispersion (PMD). The frequency-domain optical fiber channel transmission model for dual-polarization OFDM/OQAM-PON with the CD- and PMD-induced intrinsic imaginary interference (IMI) effect is systemically deduced. The intrasymbol frequency-domain averaging (ISFA) and minimum mean-squared error (MMSE) with the full loaded (FL) and half loaded (HL) preamble structures are used to mitigate the IMI effect. Compared with the conventional interference approximation method, the ISFA and MMSE offer improved receiver sensitivity. For channel estimation, the FL method is more effective than the HL method in mitigating the IMI effect and optical noise.

  8. Auto-aligning stimulated emission depletion microscope using adaptive optics.

    PubMed

    Gould, Travis J; Kromann, Emil B; Burke, Daniel; Booth, Martin J; Bewersdorf, Joerg

    2013-06-01

    Stimulated emission depletion (STED) microscopy provides diffraction-unlimited resolution in fluorescence microscopy. Imaging at the nanoscale, however, requires precise alignment of the depletion and excitation laser foci of the STED microscope. We demonstrate here that adaptive optics can be implemented to automatically align STED and confocal images with a precision of 4.3 ± 2.3 nm.

  9. Dual collection mode optical microscope with single-pixel detection

    NASA Astrophysics Data System (ADS)

    Rodríguez, A. D.; Clemente, P.; Fernández-Alonso, Mercedes; Tajahuerce, E.; Lancis, J.

    2015-07-01

    In this work we have developed a single-pixel optical microscope that provides both re ection and transmission images of the sample under test by attaching a diamond pixel layout DMD to a commercial inverted microscope. Our system performs simultaneous measurements of re ection and transmission modes. Besides, in contrast with a conventional system, in our single-element detection system both images belong, unequivocally, to the same plane of the sample. Furthermore, we have designed an algorithm to modify the shape of the projected patterns that improves the resolution and prevents the artifacts produced by the diamond pixel architecture.

  10. Optical alignment and spinning of laser-trapped microscopic particles

    NASA Astrophysics Data System (ADS)

    Friese, M. E. J.; Nieminen, T. A.; Heckenberg, N. R.; Rubinsztein-Dunlop, H.

    1998-07-01

    Light-induced rotation of absorbing microscopic particles by transfer of angular momentum from light to the material raises the possibility of optically driven micromachines. The phenomenon has been observed using elliptically polarized laser beams or beams with helical phase structure,. But it is difficult to develop high power in such experiments because of overheating and unwanted axial forces, limiting the achievable rotation rates to a few hertz. This problem can in principle be overcome by using transparent particles, transferring angular momentum by a mechanism first observed by Beth in 1936, when he reported a tiny torque developed in a quartz `wave-plate' owing to the change in polarization of transmitted light. Here we show that an optical torque can be induced on microscopic birefringent particles of calcite held by optical tweezers. Depending on the polarization of the incident beam, the particles either become aligned with the plane of polarization (and thus can be rotated through specified angles) or spin with constant rotation frequency. Because these microscopic particles are transparent, they can be held in three-dimensional optical traps at very high power without heating, leading to rotation rates of over 350Hz.

  11. Low-price optical microscope for school science education

    NASA Astrophysics Data System (ADS)

    Hoshimiya, Tsutomu; Kumagai, Masaaki

    2007-06-01

    In schools, scientific education with an optical microscope is popularly used. However, scanning apparatus for the microscope is very expensive such that the price is several times higher than the microscope itself. In order to activate children's interest in science, a low-price scanning and imaging function unit compatible to conventional optical microscopes used in schools was designed and manufactured using a personal computer (PC) used in all elementally and middle school education. The designing of imaging apparatus includes two choices: (i) using imaging device (reflection-type), or (ii) using photo-sensor and scanning device (transmission-type). In this paper, the latter method is adopted, considering the educational effect using "Lambert-Beer's law". This apparatus measures optical transmittance of modulated visible light with a photo-detector, and uses audio-input unit of PC as an A/D converter. Scanning unit with a pair of pulse motor drives was also used. Control software was built on Knoppix (an operating system based on freeware Linux), however it is very easy to rewrite to Windows application. By these reasons, this apparatus is low-price (less than microscope price) so that it is one of the best candidates for science education application in schools. As a biological specimen, a wing of spider wasp (Pompilidae) was used. Measured region was 10mm×10mm and the resolution was 100×100 pixels. The photograph of original specimen and the obtained image were shown in Figures (a) and (b), respectively. The obtained image showed a well-resolved detailed structure of the wing. Scanning was done by an external scanning apparatus. However, feeding of scanning pulses through printer port to stepping motor will be available based on the same method.

  12. Some optical principles of the clinical specular microscope.

    PubMed

    Bourne, W M; Enoch, J M

    1976-01-01

    The clinical specular microscope is used to examine and photograph human endothelial cells in vivo. An optical analysis is presented here in simple form to aid the ophthalmologist or visual scientist in understanding how this instrument can be used in a quantitative manner to measure the size of the magnified endothelial cells and the thickness of the overlying cornea. An error analysis is discussed in order to demonstrate some aspects of the precision of the determination.

  13. 3D adaptive optics in a light sheet microscope.

    PubMed

    Bourgenot, Cyril; Saunter, Christopher D; Taylor, Jonathan M; Girkin, John M; Love, Gordon D

    2012-06-04

    We report on a single plane illumination microscope (SPIM) incorporating adaptive optics in the imaging arm. We show how aberrations can occur from the sample mounting tube and quantify the aberrations both experimentally and computationally. A wavefront sensorless approach was taken to imaging a green fluorescent protein (GFP) labelled transgenic zebrafish. We show improvements in image quality whilst recording a 3D "z-stack" and show how the aberrations come from varying depths in the fish.

  14. Microscopic Studies of Quantum Phase Transitions in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Bakr, Waseem S.

    2011-12-01

    In this thesis, I report on experiments that microscopically probe quantum phase transitions of ultracold atoms in optical lattices. We have developed a "quantum gas microscope" that allowed, for the first time, optical imaging and manipulation of single atoms in a quantum-degenerate gas on individual sites of an optical lattice. This system acts as a quantum simulator of strongly correlated materials, which are currently the subject of intense research because of the technological potential of high--T c superconductors and spintronic materials. We have used our microscope to study the superfluid to Mott insulator transition in bosons and a magnetic quantum phase transition in a spin system. In our microscopic study of the superfluid-insulator transition, we have characterized the on-site number statistics in a space- and time-resolved manner. We observed Mott insulators with fidelities as high as 99%, corresponding to entropies of 0.06kB per particle. We also measured local quantum dynamics and directly imaged the shell structure of the Mott insulator. I report on the first quantum magnetism experiments in optical lattices. We have realized a quantum Ising chain in a magnetic field, and observed a quantum phase transition between a paramagnet and antiferromagnet. We achieved strong spin interactions by encoding spins in excitations of a Mott insulator in a tilted lattice. We detected the transition by measuring the total magnetization of the system across the transition using in-situ measurements as well as the Neel ordering in the antiferromagnetic state using noise-correlation techniques. We characterized the dynamics of domain formation in the system. The spin mapping introduced opens up a new path to realizing more exotic states in optical lattices including spin liquids and quantum valence bond solids. As our system sizes become larger, simulating their physics on classical computers will require exponentially larger resources because of entanglement build

  15. Quadrature-Quadrature Phase Shift Keying.

    DTIC Science & Technology

    1986-09-01

    Q 2PSK for the data stream a (t) in Figure 3.1 ................................................ 27 3.3. Spectral densities of OQPSK , MSK and Q’PSK...Offset Quadrature Phase Shift Keying ( OQPSK ). Minimum Shift Keying ( vISK ), Quadrature Overlapped taised Cosine ( QOW signalling scheme, Tamed Frequency...orthogonal; hence the name %liniliur ’t Keving (AfSK) . The baseband power spectral densities S~.f) a1nd( o’,,, r QPSlK (or OQPSk . and NLSK are given by

  16. A super-oscillatory lens optical microscope for subwavelength imaging.

    PubMed

    Rogers, Edward T F; Lindberg, Jari; Roy, Tapashree; Savo, Salvatore; Chad, John E; Dennis, Mark R; Zheludev, Nikolay I

    2012-03-25

    The past decade has seen an intensive effort to achieve optical imaging resolution beyond the diffraction limit. Apart from the Pendry-Veselago negative index superlens, implementation of which in optics faces challenges of losses and as yet unattainable fabrication finesse, other super-resolution approaches necessitate the lens either to be in the near proximity of the object or manufactured on it, or work only for a narrow class of samples, such as intensely luminescent or sparse objects. Here we report a new super-resolution microscope for optical imaging that beats the diffraction limit of conventional instruments and the recently demonstrated near-field optical superlens and hyperlens. This non-invasive subwavelength imaging paradigm uses a binary amplitude mask for direct focusing of laser light into a subwavelength spot in the post-evanescent field by precisely tailoring the interference of a large number of beams diffracted from a nanostructured mask. The new technology, which--in principle--has no physical limits on resolution, could be universally used for imaging at any wavelength and does not depend on the luminescence of the object, which can be tens of micrometres away from the mask. It has been implemented as a straightforward modification of a conventional microscope showing resolution better than λ/6.

  17. 2  ×  2 multiple-input multiple-output optical-wireless integration system based on optical independent-sideband modulation enabled by an in-phase/quadrature modulator.

    PubMed

    Li, Xinying; Yu, Jianjun

    2016-07-01

    We propose a novel and simple 2×2 multiple-input multiple-output (MIMO) optical-wireless integration system, in which optical independent-sideband modulation enabled by an in-phase/quadrature (I/Q) modulator, instead of optical polarization multiplexing, is used to assist the simultaneous generation of two wireless millimeter-wave (mm-wave) signals. Software-based digital signal processing is used to generate the driving signal for the I/Q modulator, the output of which is two independent single-sideband optical vector signals located at two sides of a large central optical carrier. Based on our proposed 2×2 MIMO optical-wireless integration system, we experimentally demonstrate the simultaneous generation and 2×2 MIMO wireless delivery of two independent 40-GHz quadrature-phase-shift-keying (QPSK) wireless mm-wave signals. Each 40-GHz QPSK wireless mm-wave signal can carry up to 4-Gbaud transmitter data with a bit-error ratio less than the hard-decision forward-error-correction threshold of 3.8×10-3.

  18. Compact microscope-based 850-nm optical tweezers

    NASA Astrophysics Data System (ADS)

    Frediani, Carlo; Grego, S.; Guidoni, L.; Arimondo, Ennio

    1996-01-01

    Emission from a single mode 100 mW laser diode at 850 nm is used for realizing optical tweezers: the laser beam is introduced into a microscope and focused by the objective into the object plane. Injection of the beam into a 40X microscope objective has been studied and the position and the size of the waist measured. The trap performance was studied as a function of the dimensions of the trapped particles. Trapping of polystyrene latex spheres of different size (from 0.2 micrometer to 6 micrometer) was observed in different conditions of laser power and transverse velocity of the spheres. Biological objects, Tetraselmis, of large dimension (around 10 micrometer) were also studied. We demonstrate the existence of an optimal range of size of the particles to be trapped. Furthermore we measure minimum trapping power required for trapping and the maximum speed of the trapped objects as a function of the dimensions.

  19. Microscopic model for all optical switching in ferromagnets

    NASA Astrophysics Data System (ADS)

    Cornelissen, T. D.; Córdoba, R.; Koopmans, B.

    2016-04-01

    The microscopic mechanism behind the all optical switching (AOS) in ferromagnets has triggered intense scientific debate. Here, the microscopic three-temperature model is utilized to describe AOS in a perpendicularly magnetized ferromagnetic Co/Pt system. We demonstrate that AOS in such a ferromagnet can be explained with the Inverse Faraday Effect (IFE). The influence of the strength and lifetime of the IFE induced field pulse on the switching process are investigated. We found that because of strong spin-orbit coupling, the minimal lifetime of the IFE needed to obtain switching is of the order of 0.1 ps, which is shorter than previously assumed. Moreover, spatial images of the domain pattern after AOS in Co/Pt, as well as their dependence on applying an opposite magnetic field, are qualitatively reproduced.

  20. The Quadrature Master Equations

    NASA Astrophysics Data System (ADS)

    Hassan, N. J.; Pourdarvish, A.; Sadeghi, J.; Olaomi, J. O.

    2017-04-01

    In this paper, we derive the non-Markovian stochastic equation of motion (SEM) and master equations (MEs) for the open quantum system by using the non-Markovian stochastic Schrödinger equations (SSEs) for the quadrature unraveling in linear and nonlinear cases. The SSEs for quadrature unraveling arise as a special case of a quantum system. Also we derive the Markovian SEM and ME by using linear and nonlinear Itô SSEs for the measurement probabilities. In linear non-Markovian case, we calculate the convolutionless linear quadrature non-Markovian SEM and ME. We take advantage from example and show that corresponding theory.

  1. Dynamic-focusing microscope objective for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Murali, Supraja; Rolland, Jannick

    2007-01-01

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

  2. Optically Sectioning Ocular Fluorometer Microscope: Applications To The Cornea

    NASA Astrophysics Data System (ADS)

    Masters, Barry R.

    1988-06-01

    An optically sectioning ocular fluorometer microscope is described with the capability of measuring the emission spectra of molecules in planes along the microscope axis. Its unique feature is that the objective is attached to a piezoelectric driver and scans from the tear film to the aqueous humor. This permits measurements on living animals and adoption for clinical use. The excitation light from a laser (nitrogen, dye, argon or helium cadmium) couples to the microscope via a quartz optical fiber. The light is projected through a 100 PM slit on the excitation side, through one half of the objective. The emitted light is collected by the second half of the objective and passes a second 100 pm slit in the conjugate plane of the eyepiece. The depth resolution is 6 um with an 100x objective, and 18 PM with a 50 power objective. The fluorescence is coupled by a quartz fiber to an optical spectrum analyzer. It consists of a monochromator with two microchannel plates attached to a linear diode array. The photocathode of the detector is gated for use with pulsed lasers or it can operate in the continuous mode. The applications include fluorescence measurements on thin layered structures. The present study involves the noninvasive measurement of oxidative metabolism of the component layers of the in vivo cornea. This is based on fluorescence measurements of the reduced pyridine nucleotide in the cornea. The fluorescence signals from the corneal epithelial (30 μm) and endothelial (4 μm) are clearly defined. Other applications to ophthalmology include studies of the fluorescence form the component layers of the ocular lens. Support from N.I.I. EY06958.

  3. Calibration of scanning tunneling microscope transducers using optical beam deflection

    NASA Astrophysics Data System (ADS)

    Wetsel, G. C., Jr.; McBride, S. E.; Warmack, R. J.; van de Sande, B.

    1989-08-01

    An accurate, sensitive, easily implemented method of calibration of the elastic displacement of piezoelectric transducers used in scanning tunneling microscopes has been developed. The axial displacement for both static and harmonic excitation has been measured using laser beam deflection amplified by an optical magnification system. For harmonic excitation where lock-in amplifier detection can be utilized, displacements as small as 0.03 Å have been measured. Measurements on PZT-5H and PZT-8 transducers over a range of five orders of magnitude in applied voltage demonstrate the power of the method in calibration of displacements from the subangstrom to the nonlinear region with an uncertainty of about 4%.

  4. Artificial testing targets with controllable blur for adaptive optics microscopes

    NASA Astrophysics Data System (ADS)

    Hattori, Masayuki; Tamada, Yosuke; Murata, Takashi; Oya, Shin; Hasebe, Mitsuyasu; Hayano, Yutaka; Kamei, Yasuhiro

    2017-08-01

    This letter proposes a method of configuring a testing target to evaluate the performance of adaptive optics microscopes. In this method, a testing slide with fluorescent beads is used to simultaneously determine the point spread function and the field of view. The point spread function is reproduced to simulate actual biological samples by etching a microstructure on the cover glass. The fabrication process is simplified to facilitate an onsite preparation. The artificial tissue consists of solid materials and silicone oil and is stable for use in repetitive experiments.

  5. Positive quadrature formulas III

    NASA Astrophysics Data System (ADS)

    Peherstorfer, Franz

    2008-12-01

    First we discuss briefly our former characterization theorem for positive interpolation quadrature formulas (abbreviated qf), provide an equivalent characterization in terms of Jacobi matrices, and give links and applications to other qf, in particular to Gauss-Kronrod quadratures and recent rediscoveries. Then for any polynomial t_n which generates a positive qf, a weight function (depending on n ) is given with respect to which t_n is orthogonal to mathbb{P}_{n-1} . With the help of this result an asymptotic representation of the quadrature weights is derived. In general the asymptotic behaviour is different from that of the Gaussian weights. Only under additional conditions do the quadrature weights satisfy the so-called circle law. Corresponding results are obtained for positive qf of Radau and Lobatto type.

  6. High-voltage scanning ion microscope: Beam optics and design

    NASA Astrophysics Data System (ADS)

    Magilin, D.; Ponomarev, A.; Rebrov, V.; Ponomarov, A.

    2015-05-01

    This article is devoted to the conceptual design of a compact high-voltage scanning ion microscope (HVSIM). In an HVSIM design, the ion optical system is based on a high-brightness ion source. Specifically, the ion optical system is divided into two components: an ion injector and a probe-forming system (PFS) that consists of an accelerating tube and a multiplet of quadrupole lenses. The crossover is formed and controlled by the injector, which acts as an object collimator, and is focused on the image plane by the PFS. The ion microprobe has a size of 0.1 μm and an energy of 2 MeV. When the influence of the chromatic and third-order aberrations is theoretically taken into account, the HVSIM forms an ion microprobe.

  7. Silicon photonic integrated circuit swept-source optical coherence tomography receiver with dual polarization, dual balanced, in-phase and quadrature detection.

    PubMed

    Wang, Zhao; Lee, Hsiang-Chieh; Vermeulen, Diedrik; Chen, Long; Nielsen, Torben; Park, Seo Yeon; Ghaemi, Allan; Swanson, Eric; Doerr, Chris; Fujimoto, James

    2015-07-01

    Optical coherence tomography (OCT) is a widely used three-dimensional (3D) optical imaging method with many biomedical and non-medical applications. Miniaturization, cost reduction, and increased functionality of OCT systems will be critical for future emerging clinical applications. We present a silicon photonic integrated circuit swept-source OCT (SS-OCT) coherent receiver with dual polarization, dual balanced, in-phase and quadrature (IQ) detection. We demonstrate multiple functional capabilities of IQ polarization resolved detection including: complex-conjugate suppressed full-range OCT, polarization diversity detection, and polarization-sensitive OCT. To our knowledge, this is the first demonstration of a silicon photonic integrated receiver for OCT. The integrated coherent receiver provides a miniaturized, low-cost solution for SS-OCT, and is also a key step towards a fully integrated high speed SS-OCT system with good performance and multi-functional capabilities. With further performance improvement and cost reduction, photonic integrated technology promises to greatly increase penetration of OCT systems in existing applications and enable new applications.

  8. Silicon photonic integrated circuit swept-source optical coherence tomography receiver with dual polarization, dual balanced, in-phase and quadrature detection

    PubMed Central

    Wang, Zhao; Lee, Hsiang-Chieh; Vermeulen, Diedrik; Chen, Long; Nielsen, Torben; Park, Seo Yeon; Ghaemi, Allan; Swanson, Eric; Doerr, Chris; Fujimoto, James

    2015-01-01

    Optical coherence tomography (OCT) is a widely used three-dimensional (3D) optical imaging method with many biomedical and non-medical applications. Miniaturization, cost reduction, and increased functionality of OCT systems will be critical for future emerging clinical applications. We present a silicon photonic integrated circuit swept-source OCT (SS-OCT) coherent receiver with dual polarization, dual balanced, in-phase and quadrature (IQ) detection. We demonstrate multiple functional capabilities of IQ polarization resolved detection including: complex-conjugate suppressed full-range OCT, polarization diversity detection, and polarization-sensitive OCT. To our knowledge, this is the first demonstration of a silicon photonic integrated receiver for OCT. The integrated coherent receiver provides a miniaturized, low-cost solution for SS-OCT, and is also a key step towards a fully integrated high speed SS-OCT system with good performance and multi-functional capabilities. With further performance improvement and cost reduction, photonic integrated technology promises to greatly increase penetration of OCT systems in existing applications and enable new applications. PMID:26203382

  9. Analog quadrature signal to phase angle data conversion by a quadrature digitizer and quadrature counter

    DOEpatents

    Buchenauer, C.J.

    1981-09-23

    The quadrature phase angle phi (t) of a pair of quadrature signals S/sub 1/(t) and S/sub 2/(t) is digitally encoded on a real time basis by a quadrature digitizer for fractional phi (t) rotational excursions and by a quadrature up/down counter for full phi (t) rotations. The pair of quadrature signals are of the form S/sub 1/(t) = k(t) sin phi (t) and S/sub 2/(t) = k(t) cos phi (t) where k(t) is a signal common to both. The quadrature digitizer and the quadrature up/down counter may be used together or singularly as desired or required. Optionally, a digital-to-analog converter may follow the outputs of the quadrature digitizer and the quadrature up/down counter to provide an analog signal output of the quadrature phase angle phi (t).

  10. Analog quadrature signal to phase angle data conversion by a quadrature digitizer and quadrature counter

    DOEpatents

    Buchenauer, C. Jerald

    1984-01-01

    The quadrature phase angle .phi.(t) of a pair of quadrature signals S.sub.1 (t) and S.sub.2 (t) is digitally encoded on a real time basis by a quadrature digitizer for fractional .phi.(t) rotational excursions and by a quadrature up/down counter for full .phi.(t) rotations. The pair of quadrature signals are of the form S.sub.1 (t)=k(t) sin .phi.(t) and S.sub.2 (t)=k(t) cos .phi.(t) where k(t) is a signal common to both. The quadrature digitizer and the quadrature up/down counter may be used together or singularly as desired or required. Optionally, a digital-to-analog converter may follow the outputs of the quadrature digitizer and the quadrature up/down counter to provide an analog signal output of the quadrature phase angle .phi.(t).

  11. HOMER: the Holographic Optical Microscope for Education and Research

    NASA Astrophysics Data System (ADS)

    Luviano, Anali

    Holography was invented in 1948 by Dennis Gabor and has undergone major advancements since the 2000s leading to the development of commercial digital holographic microscopes (DHM). This noninvasive form of microscopy produces a three-dimensional (3-D) digital model of a sample without altering or destroying the sample, thus allowing the same sample to be studied multiple times. HOMER-the Holographic Optical Microscope for Education and Research-produces a 3-D image from a two-dimensional (2-D) interference pattern captured by a camera that is then put through reconstruction software. This 2-D pattern is created when a reference wave interacts with the sample to produce a secondary wave that interferes with the unaltered part of the reference wave. I constructed HOMER to be an efficient, portable in-line DHM using inexpensive material and free reconstruction software. HOMER uses three different-colored LEDs as light sources. I am testing the performance of HOMER with the goal of producing tri-color images of samples. I'm using small basic biological samples to test the effectiveness of HOMER and plan to transition to complex cellular and biological specimens as I pursue my interest in biophysics. Norwich University.

  12. Transmission electron microscope sample holder with optical features

    DOEpatents

    Milas, Mirko [Port Jefferson, NY; Zhu, Yimei [Stony Brook, NY; Rameau, Jonathan David [Coram, NY

    2012-03-27

    A sample holder for holding a sample to be observed for research purposes, particularly in a transmission electron microscope (TEM), generally includes an external alignment part for directing a light beam in a predetermined beam direction, a sample holder body in optical communication with the external alignment part and a sample support member disposed at a distal end of the sample holder body opposite the external alignment part for holding a sample to be analyzed. The sample holder body defines an internal conduit for the light beam and the sample support member includes a light beam positioner for directing the light beam between the sample holder body and the sample held by the sample support member.

  13. Performance evaluation of a sensorless adaptive optics multiphoton microscope.

    PubMed

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

    2016-03-01

    A wavefront sensorless adaptive optics technique was combined with a custom-made multiphoton microscope to correct for specimen-induced aberrations. A liquid-crystal-on-silicon (LCoS) modulator was used to systematically generate Zernike modes during image recording. The performance of the instrument was evaluated in samples providing different nonlinear signals and the benefit of correcting higher order aberrations was always noticeable (in both contrast and resolution). The optimum aberration pattern was stable in time for the samples here involved. For a particular depth location within the sample, the wavefront to be precompensated was independent on the size of the imaged area (up to ∼ 360 × 360 μm(2)). The mode combination optimizing the recorded image depended on the Zernike correction control sequence; however, the final images hardly differed. At deeper locations, a noticeable dominance of spherical aberration was found. The influence of other aberration terms was also compared to the effect of the spherical aberration.

  14. Fast optical monitoring of microscopic excitation patterns in cardiac muscle.

    PubMed Central

    Müller, W; Windisch, H; Tritthart, H A

    1989-01-01

    Many vital processes depend on the generation, changes, and conduction of cellular transmembrane potentials. Optical monitoring systems are well suited to detect such cellular electrical activities in networks of excitable cells and also tissues simultaneously at multiple sites. Here, an exceptionally fast array system (16 x 16 photodiodes, up to 4,000,000 samples per second, 12-bit resolution) for imaging voltage-sensitive dye fluorescence, permitted real time measurements of excitation patterns at a microscopic size scale (256 pixels within an area of 1.8-8 mm2), in rat cardiac muscle in vitro. Results emphasize a recent hypothesis for cardiac impulse conduction, based on cardiac structural complexities, that is contradictory to all continuous cable theory models. Images FIGURE 2 PMID:2790142

  15. Digital Quadrature Modulation.

    DTIC Science & Technology

    1978-01-05

    imbalances between the two mixers is shown. Section 3 presents the digital quadrature modulation method and Section 4 presents two imple- mentations of the...Figure 1. Analog Quadrature Modulator. Ih output signal is given by: 4(t) 2 s1 (t) + s2 (t) N*ere 91 (t) = z(t)coswct a2 (t) - -y(t)sict (1) |r 3 Let...wawc)+Z(a+w,)+Z*(-w- )j ( 3 ) Similarly s2() -(l/4)[Z(a-w )-Z (-w~w )-Z(atwc)+Z (-w-wc)] (4) Thus the spectrum of the output it S(w) - S1 (W) + S2(w

  16. Quadrature, Interpolation and Observability

    NASA Technical Reports Server (NTRS)

    Hodges, Lucille McDaniel

    1997-01-01

    Methods of interpolation and quadrature have been used for over 300 years. Improvements in the techniques have been made by many, most notably by Gauss, whose technique applied to polynomials is referred to as Gaussian Quadrature. Stieltjes extended Gauss's method to certain non-polynomial functions as early as 1884. Conditions that guarantee the existence of quadrature formulas for certain collections of functions were studied by Tchebycheff, and his work was extended by others. Today, a class of functions which satisfies these conditions is called a Tchebycheff System. This thesis contains the definition of a Tchebycheff System, along with the theorems, proofs, and definitions necessary to guarantee the existence of quadrature formulas for such systems. Solutions of discretely observable linear control systems are of particular interest, and observability with respect to a given output function is defined. The output function is written as a linear combination of a collection of orthonormal functions. Orthonormal functions are defined, and their properties are discussed. The technique for evaluating the coefficients in the output function involves evaluating the definite integral of functions which can be shown to form a Tchebycheff system. Therefore, quadrature formulas for these integrals exist, and in many cases are known. The technique given is useful in cases where the method of direct calculation is unstable. The condition number of a matrix is defined and shown to be an indication of the the degree to which perturbations in data affect the accuracy of the solution. In special cases, the number of data points required for direct calculation is the same as the number required by the method presented in this thesis. But the method is shown to require more data points in other cases. A lower bound for the number of data points required is given.

  17. Effect of spherical aberration on the imaging properties of scanning optical microscopes.

    PubMed

    Sheppard, C J; Wilson, T

    1979-04-01

    The effect of primary spherical aberration and defocus on the imaging properties of scanning optical microscopes with weak objects is considered. Optically there are two types of scanning microscope. Type 1 scanning microscopes behave identically to conventional microscopes, but in type 2 scanning microscopes animaginary part is introduced into the transfer function. In general, therefore, it is important that the lenses be adequately corrected, but for objects with very weak amplitude contrast the effect may be a useful way of obtaining phase imaging. Experimental demonstration of the effect of spherical aberration is reported.

  18. Sub-nanosecond time-resolved near-field scanning magneto-optical microscope.

    PubMed

    Rudge, J; Xu, H; Kolthammer, J; Hong, Y K; Choi, B C

    2015-02-01

    We report on the development of a new magnetic microscope, time-resolved near-field scanning magneto-optical microscope, which combines a near-field scanning optical microscope and magneto-optical contrast. By taking advantage of the high temporal resolution of time-resolved Kerr microscope and the sub-wavelength spatial resolution of a near-field microscope, we achieved a temporal resolution of ∼50 ps and a spatial resolution of <100 nm. In order to demonstrate the spatiotemporal magnetic imaging capability of this microscope, the magnetic field pulse induced gyrotropic vortex dynamics occurring in 1 μm diameter, 20 nm thick CoFeB circular disks has been investigated. The microscope provides sub-wavelength resolution magnetic images of the gyrotropic motion of the vortex core at a resonance frequency of ∼240 MHz.

  19. Increasing student understanding of microscope optics by building and testing the limits of simple, hand-made model microscopes.

    PubMed

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

    2012-01-01

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

  20. Progress toward optical biopsy: bringing the microscope to the patient.

    PubMed

    Newton, Richard C; Kemp, Samuel V; Shah, Pallav L; Elson, Daniel; Darzi, Ara; Shibuya, Kiyoshi; Mulgrew, Stephen; Yang, Guang-Zhong

    2011-04-01

    The investigation of many lung diseases currently requires bronchoscopic or surgical histopathological tissue biopsy. This creates risks for patients and entails processing costs and delays in diagnosis. However, several mainly probe-based biophotonic techniques that can image solitary lesions and diffuse lung diseases are fuelling a paradigm shift toward real-time in vivo diagnosis. Optical coherence tomography (OCT) uses near-infrared light in a process analogous to ultrasonography to image the mucosal and submucosal tissue boundaries of the bronchial tree. With 15-μm resolution, early work suggests it can differentiate between neoplasia, carcinoma in situ, dysplasia, and metaplasia based around epithelial thickness and breaches in the basement membrane. Probe-based confocal laser endomicroscopy (pCLE) has superior resolution but less penetration than OCT and employs blue argon laser light to fluoresce the endogenous elastin of (1) the acinar scaffold of the peripheral lung and (2) the basement membrane lying under bronchial mucosa. Initial studies suggest that the regular fibre arrangement of the basement membrane is altered in the presence of overlying malignant epithelium. pCLE produces detailed representations of the alveolar septal walls, microvessels, and some inflammatory cells. A third device, the endocytoscope, is a contact microscope requiring contrast agent to provide subcellular resolution of bronchial mucosa. Further development of these "optical biopsy" techniques and evaluation of diagnostic sensitivity and specificity of the acquired images are needed before they can be considered effective methods for eliminating the need for, and thus risks of, pinch biopsy to enable real-time diagnosis to streamline management.

  1. Cascade photonic integrated circuit architecture for electro-optic in-phase quadrature/single sideband modulation or frequency conversion.

    PubMed

    Hasan, Mehedi; Hall, Trevor

    2015-11-01

    A photonic integrated circuit architecture for implementing frequency upconversion is proposed. The circuit consists of a 1×2 splitter and 2×1 combiner interconnected by two stages of differentially driven phase modulators having 2×2 multimode interference coupler between the stages. A transfer matrix approach is used to model the operation of the architecture. The predictions of the model are validated by simulations performed using an industry standard software tool. The intrinsic conversion efficiency of the proposed design is improved by 6 dB over the alternative functionally equivalent circuit based on dual parallel Mach-Zehnder modulators known in the prior art. A two-tone analysis is presented to study the linearity of the proposed circuit, and a comparison is provided over the alternative. The proposed circuit is suitable for integration in any platform that offers linear electro-optic phase modulation such as LiNbO(3), silicon, III-V, or hybrid technology.

  2. Inspection strategy for LIGA microstructures using a programmable optical microscope.

    SciTech Connect

    Kurfess, Thomas R; Aigeldinger, Georg; Ceremuga, Joseph T.

    2004-07-01

    The LIGA process has the ability to fabricate very precise, high aspect ratio mesoscale structures with microscale features [l]. The process consists of multiple steps before a final part is produced. Materials native to the LIGA process include metals and photoresists. These structures are routinely measured for quality control and process improvement. However, metrology of LIGA structures is challenging because of their high aspect ratio and edge topography. For the scale of LIGA structures, a programmable optical microscope is well suited for lateral (XU) critical dimension measurements. Using grayscale gradient image processing with sub-pixel interpolation, edges are detected and measurements are performed. As with any measurement, understanding measurement uncertainty is necessary so that appropriate conclusions are drawn from the data. Therefore, the abilities of the inspection tool and the obstacles presented by the structures under inspection should be well understood so that precision may be quantified. This report presents an inspection method for LIGA microstructures including a comprehensive assessment of the uncertainty for each inspection scenario.

  3. Correlated quadratures of resonance fluorescence and the generalized uncertainty relation

    NASA Technical Reports Server (NTRS)

    Arnoldus, Henk F.; George, Thomas F.; Gross, Rolf W. F.

    1994-01-01

    Resonance fluorescence from a two-state atom has been predicted to exhibit quadrature squeezing below the Heisenberg uncertainty limit, provided that the optical parameters (Rabi frequency, detuning, laser linewidth, etc.) are chosen carefully. When the correlation between two quadratures of the radiation field does not vanish, however, the Heisenberg limit for quantum fluctuations might be an unrealistic lower bound. A generalized uncertainty relation, due to Schroedinger, takes into account the possible correlation between the quadrature components of the radiation, and it suggests a modified definition of squeezing. We show that the coherence between the two levels of a laser-driven atom is responsible for the correlation between the quadrature components of the emitted fluorescence, and that the Schrodinger uncertainty limit increases monotonically with the coherence. On the other hand, the fluctuations in the quadrature field diminish with an increasing coherence, and can disappear completely when the coherence reaches 1/2, provided that certain phase relations hold.

  4. LayerOptics: Microscopic modeling of optical coefficients in layered materials

    NASA Astrophysics Data System (ADS)

    Vorwerk, Christian; Cocchi, Caterina; Draxl, Claudia

    2016-04-01

    Theoretical spectroscopy is a powerful tool to describe and predict optical properties of materials. While nowadays routinely performed, first-principles calculations only provide bulk dielectric tensors in Cartesian coordinates. These outputs are hardly comparable with experimental data, which are typically given by macroscopic quantities, crucially depending on the laboratory setup. Even more serious discrepancies can arise for anisotropic materials, e.g., organic crystals, where off-diagonal elements of the dielectric tensor can significantly contribute to the spectral features. Here, we present LayerOptics, a versatile and user-friendly implementation, based on the solution of the Maxwell's equations for anisotropic materials, to compute optical coefficients in anisotropic layered materials. We apply this tool for post-processing full dielectric tensors of molecular materials, including excitonic effects, as computed from many-body perturbation theory using the exciting code. For prototypical examples, ranging from optical to X-ray frequencies, we show the importance of combining accurate ab initio methods to obtain dielectric tensors, with the solution of the Maxwell's equations to compute optical coefficients accounting for optical anisotropy of layered systems. Good agreement with experimental data supports the potential of our approach, in view of achieving microscopic understanding of spectroscopic properties in complex materials.

  5. Szego-Lobatto quadrature rules

    NASA Astrophysics Data System (ADS)

    Jagels, Carl; Reichel, Lothar

    2007-03-01

    Gauss-type quadrature rules with one or two prescribed nodes are well known and are commonly referred to as Gauss-Radau and Gauss-Lobatto quadrature rules, respectively. Efficient algorithms are available for their computation. Szego quadrature rules are analogs of Gauss quadrature rules for the integration of periodic functions; they integrate exactly trigonometric polynomials of as high degree as possible. Szego quadrature rules have a free parameter, which can be used to prescribe one node. This paper discusses an analog of Gauss-Lobatto rules, i.e., Szego quadrature rules with two prescribed nodes. We refer to these rules as Szego-Lobatto rules. Their properties as well as numerical methods for their computation are discussed.

  6. Discrete observability and numerical quadrature

    NASA Technical Reports Server (NTRS)

    Martin, Clyde F.; Wang, Xiaochang; Stamp, Mark

    1991-01-01

    The authors consider the problem of approximate observability of a one-dimensional diffusion equation on a finite spatial domain with spatial point measurements. The problem of the optimal selection of the measurement points is considered under three conditions: (1) no preassigned measurement nodes; (2) one preassigned node and; (3) two preassigned nodes. The main observation is that the optimal choice is related to three classical procedures in numerical analysis: (1) Gaussian quadrature; (2) Radau quadrature and; (3) Lobatto quadrature. It is shown that the existence of the Radau and Lobatto quadrature is closely related to classical root locus theory.

  7. Electronic post-compensation for nonlinear phase fluctuations in a 1000-km 20-Gbit/s optical quadrature phase-shift keying transmission system using the digital coherent receiver.

    PubMed

    Kikuchi, Kazuro

    2008-01-21

    We demonstrate electronic post-compensation for nonlinear phase fluctuation in a 1000-km 20-Gbit/s optical quadrature phase-shift keying (QPSK) transmission system, where group-velocity dispersion is well managed. The inter-symbol interference (ISI) at the transmitter induces the nonlinear phase fluctuation through self-phase modulation (SPM) of the signal transmitted through a fiber. However, when the optimized phase shift proportional to the intensity fluctuation is given to the complex amplitude of the signal electric field by using a digital coherent receiver, the nonlinear phase fluctuation can be reduced effectively.

  8. New scanning technique for the optical vortex microscope.

    PubMed

    Augustyniak, Ireneusz; Popiołek-Masajada, Agnieszka; Masajada, Jan; Drobczyński, Sławomir

    2012-04-01

    In the optical vortex microscopy the focused Gaussian beam with optical vortex scans a sample. An optical vortex can be introduced into a laser beam with the use of a special optical element--a vortex lens. When moving the vortex lens, the optical vortex changes its position inside the spot formed by a focused laser beam. This effect can be used as a new precise scanning technique. In this paper, we study the optical vortex behavior at the sample plane. We also estimate if the new scanning technique results in observable effects that could be used for a phase object detection.

  9. Examples of electrostatic electron optics: the Farrand and Elektros microscopes and electron mirrors.

    PubMed

    Hawkes, P W

    2012-08-01

    The role of Gertrude Rempfer in the design of the Farrand and Elektros microscopes is evoked. The study of electron mirror optics, aberration correction using mirrors and the development of microscopes employing electron mirrors are recapitulated, accompanied by a full bibliography, of earlier publications in particular.

  10. Interferometric and optical tests of water window imaging x ray microscopes

    NASA Technical Reports Server (NTRS)

    Johnson, R. Barry

    1993-01-01

    Interferometric tests of Schwarzchild X-ray Microscope are performed to evaluate the optical properties and alignment of the components. Photographic measurements of the spatial resolution, focal properties, and vignetting characteristics of the prototype Water Window Imaging X-ray Microscope are made and analyzed.

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

    ScienceCinema

    Nazaretski, Evgeny

    2016-11-23

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

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

    SciTech Connect

    Nazaretski, Evgeny

    2016-11-08

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

  13. Quantitative optical microscopy: measurement of cellular biophysical features with a standard optical microscope.

    PubMed

    Phillips, Kevin G; Baker-Groberg, Sandra M; McCarty, Owen J T

    2014-04-07

    We describe the use of a standard optical microscope to perform quantitative measurements of mass, volume, and density on cellular specimens through a combination of bright field and differential interference contrast imagery. Two primary approaches are presented: noninterferometric quantitative phase microscopy (NIQPM), to perform measurements of total cell mass and subcellular density distribution, and Hilbert transform differential interference contrast microscopy (HTDIC) to determine volume. NIQPM is based on a simplified model of wave propagation, termed the paraxial approximation, with three underlying assumptions: low numerical aperture (NA) illumination, weak scattering, and weak absorption of light by the specimen. Fortunately, unstained cellular specimens satisfy these assumptions and low NA illumination is easily achieved on commercial microscopes. HTDIC is used to obtain volumetric information from through-focus DIC imagery under high NA illumination conditions. High NA illumination enables enhanced sectioning of the specimen along the optical axis. Hilbert transform processing on the DIC image stacks greatly enhances edge detection algorithms for localization of the specimen borders in three dimensions by separating the gray values of the specimen intensity from those of the background. The primary advantages of NIQPM and HTDIC lay in their technological accessibility using "off-the-shelf" microscopes. There are two basic limitations of these methods: slow z-stack acquisition time on commercial scopes currently abrogates the investigation of phenomena faster than 1 frame/minute, and secondly, diffraction effects restrict the utility of NIQPM and HTDIC to objects from 0.2 up to 10 (NIQPM) and 20 (HTDIC) μm in diameter, respectively. Hence, the specimen and its associated time dynamics of interest must meet certain size and temporal constraints to enable the use of these methods. Excitingly, most fixed cellular specimens are readily investigated with

  14. Optimization of microscopic and macroscopic second order optical nonlinearities

    NASA Technical Reports Server (NTRS)

    Marder, Seth R.; Perry, Joseph W.

    1993-01-01

    Nonlinear optical materials (NLO) can be used to extend the useful frequency range of lasers. Frequency generation is important for laser-based remote sensing and optical data storage. Another NLO effect, the electro-optic effect, can be used to modulate the amplitude, phase, or polarization state of an optical beam. Applications of this effect in telecommunications and in integrated optics include the impression of information on an optical carrier signal or routing of optical signals between fiber optic channels. In order to utilize these effects most effectively, it is necessary to synthesize materials which respond to applied fields very efficiently. In this talk, it will be shown how the development of a fundamental understanding of the science of nonlinear optics can lead to a rational approach to organic molecules and materials with optimized properties. In some cases, figures of merit for newly developed materials are more than an order of magnitude higher than those of currently employed materials. Some of these materials are being examined for phased-array radar and other electro-optic switching applications.

  15. Differential phase contrast x-ray microimaging with scanning-imaging x-ray microscope optics.

    PubMed

    Takeuchi, Akihisa; Suzuki, Yoshio; Uesugi, Kentaro

    2012-08-01

    A novel x-ray microimaging system that consists of a scanning microscope optics with a one-dimensional focusing (line-focusing) device and an imaging microscope optics with a one-dimensional objective is developed. These two optical systems are set normal to each other regarding the optical axis. A two-dimensional image is obtained with one-dimensional translation scan of the line probe. During scans, positional data in the normal to the scanning direction are obtained simultaneously with the imaging microscope optics. Differential phase contrast (DPC) image and absorption contrast (AC) image can be arbitrarily obtained by image processing after data acquisition. Preliminary experiment has been carried out by using a couple of one-dimensional Fresnel zone plate as the linear-focusing device and the one-dimensional objective. Two-dimensional DPC and AC images of test sample have been successfully obtained with 8 keV x-rays.

  16. Three-dimensional optical transfer functions in the aberration-corrected scanning transmission electron microscope.

    PubMed

    Jones, L; Nellist, P D

    2014-05-01

    In the scanning transmission electron microscope, hardware aberration correctors can now correct for the positive spherical aberration of round electron lenses. These correctors make use of nonround optics such as hexapoles or octupoles, leading to the limiting aberrations often being of a nonround type. Here we explore the effect of a number of potential limiting aberrations on the imaging performance of the scanning transmission electron microscope through their resulting optical transfer functions. In particular, the response of the optical transfer function to changes in defocus are examined, given that this is the final aberration to be tuned just before image acquisition. The resulting three-dimensional optical transfer functions also allow an assessment of the performance of a system for focal-series experiments or optical sectioning applications. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

  17. Multimodal optical workstation for simultaneous linear, nonlinear microscopy and nanomanipulation: upgrading a commercial confocal inverted microscope.

    PubMed

    Mathew, Manoj; Santos, Susana I C O; Zalvidea, Dobryna; Loza-Alvarez, Pablo

    2009-07-01

    In this work we propose and build a multimodal optical workstation that extends a commercially available confocal microscope (Nikon Confocal C1-Si) to include nonlinear/multiphoton microscopy and optical manipulation/stimulation tools such as nanosurgery. The setup allows both subsystems (confocal and nonlinear) to work independently and simultaneously. The workstation enables, for instance, nanosurgery along with simultaneous confocal and brightfield imaging. The nonlinear microscopy capabilities are added around the commercial confocal microscope by exploiting all the flexibility offered by this microscope and without need for any mechanical or electronic modification of the confocal microscope systems. As an example, the standard differential interference contrast condenser and diascopic detector in the confocal microscope are readily used as a forward detection mount for second harmonic generation imaging. The various capabilities of this workstation, as applied directly to biology, are demonstrated using the model organism Caenorhabditis elegans.

  18. Microscopic optical model potentials for p-nucleus scattering at intermediate energies

    SciTech Connect

    Hemalatha, M.; Gambhir, Y. K.; Kailas, S.; Haider, W.

    2007-03-15

    A comparative study of the microscopic optical potentials viz., semimicroscopic with extended Jeukenne-Lejeune-Mahaux interaction and microscopic Brueckner theory using Hamada-Johnston as well as Urbana V14 soft-core internucleon interactions, has been carried out. These microscopic optical potentials are compared with that of Dirac phenomenology (DP) for the polarized proton-{sup 40}Ca elastic scattering at 35 MeV and 200 MeV. These potentials have different shapes for 200 MeV below 4 fm. In particular, for the real part of the central potential, only the Dirac phenomenology and the microscopic optical potential calculated with the Hamada-Johnston interaction exhibit the well known wine-bottle-bottom shape. It is found that the calculated observables (cross section, analyzing power and spin rotation function) using these potentials having different shapes, compare well with the experiment.

  19. Digital quadrature phase detection

    DOEpatents

    Smith, James A.; Johnson, John A.

    1992-01-01

    A system for detecting the phase of a frequency of phase modulated signal that includes digital quadrature sampling of the frequency or phase modulated signal at two times that are one quarter of a cycle of a reference signal apart, determination of the arctangent of the ratio of a first sampling of the frequency or phase modulated signal to the second sampling of the frequency or phase modulated signal, and a determination of quadrant in which the phase determination is increased by 2.pi. when the quadrant changes from the first quadrant to the fourth quadrant and decreased by 2.pi. when the quadrant changes from the fourth quadrant to the first quadrant whereby the absolute phase of the frequency or phase modulated signal can be determined using an arbitrary reference convention.

  20. Digital quadrature phase detection

    DOEpatents

    Smith, J.A.; Johnson, J.A.

    1992-05-26

    A system for detecting the phase of a frequency or phase modulated signal that includes digital quadrature sampling of the frequency or phase modulated signal at two times that are one quarter of a cycle of a reference signal apart, determination of the arctangent of the ratio of a first sampling of the frequency or phase modulated signal to the second sampling of the frequency or phase modulated signal, and a determination of quadrant in which the phase determination is increased by 2[pi] when the quadrant changes from the first quadrant to the fourth quadrant and decreased by 2[pi] when the quadrant changes from the fourth quadrant to the first quadrant whereby the absolute phase of the frequency or phase modulated signal can be determined using an arbitrary reference convention. 6 figs.

  1. Absorption contrast imaging beyond the diffraction limit with electron-beam excitation assisted optical microscope

    NASA Astrophysics Data System (ADS)

    Inami, Wataru; Fukuta, Masahiro; Kawata, Yoshimasa; Terakawa, Susumu

    2017-04-01

    We demonstrated that the high spatial resolution absorption contrast imaging of the crystal of vitamin B9 having absorption at UV wavelengths. The absorption wavelength matches with the wavelength of the emission of the fluorescent thin film of an electron-beam excitation assisted (EXA) optical microscope. The fine crystal structure was imaged beyond the optical diffraction limit. The image contrast corresponded with the thickness of the crystal. The illumination light is absorbed with the vitamin B9 crystal and the intensity of the transmitted light depends on the thickness of the vitamin B9 crystal. The EXA optical microscope is useful for analysis of growth of a crystal, bioimaging, and so on.

  2. Optimized quadrature surface coil designs

    PubMed Central

    Kumar, Ananda; Bottomley, Paul A.

    2008-01-01

    Background Quadrature surface MRI/MRS detectors comprised of circular loop and figure-8 or butterfly-shaped coils offer improved signal-to-noise-ratios (SNR) compared to single surface coils, and reduced power and specific absorption rates (SAR) when used for MRI excitation. While the radius of the optimum loop coil for performing MRI at depth d in a sample is known, the optimum geometry for figure-8 and butterfly coils is not. Materials and methods The geometries of figure-8 and square butterfly detector coils that deliver the optimum SNR are determined numerically by the electromagnetic method of moments. Figure-8 and loop detectors are then combined to create SNR-optimized quadrature detectors whose theoretical and experimental SNR performance are compared with a novel quadrature detector comprised of a strip and a loop, and with two overlapped loops optimized for the same depth at 3 T. The quadrature detection efficiency and local SAR during transmission for the three quadrature configurations are analyzed and compared. Results The SNR-optimized figure-8 detector has loop radius r8 ∼ 0.6d, so r8/r0 ∼ 1.3 in an optimized quadrature detector at 3 T. The optimized butterfly coil has side length ∼ d and crossover angle of ≥ 150° at the center. Conclusions These new design rules for figure-8 and butterfly coils optimize their performance as linear and quadrature detectors. PMID:18057975

  3. A Microscopic Optically Tracking Navigation System That Uses High-resolution 3D Computer Graphics.

    PubMed

    Yoshino, Masanori; Saito, Toki; Kin, Taichi; Nakagawa, Daichi; Nakatomi, Hirofumi; Oyama, Hiroshi; Saito, Nobuhito

    2015-01-01

    Three-dimensional (3D) computer graphics (CG) are useful for preoperative planning of neurosurgical operations. However, application of 3D CG to intraoperative navigation is not widespread because existing commercial operative navigation systems do not show 3D CG in sufficient detail. We have developed a microscopic optically tracking navigation system that uses high-resolution 3D CG. This article presents the technical details of our microscopic optically tracking navigation system. Our navigation system consists of three components: the operative microscope, registration, and the image display system. An optical tracker was attached to the microscope to monitor the position and attitude of the microscope in real time; point-pair registration was used to register the operation room coordinate system, and the image coordinate system; and the image display system showed the 3D CG image in the field-of-view of the microscope. Ten neurosurgeons (seven males, two females; mean age 32.9 years) participated in an experiment to assess the accuracy of this system using a phantom model. Accuracy of our system was compared with the commercial system. The 3D CG provided by the navigation system coincided well with the operative scene under the microscope. Target registration error for our system was 2.9 ± 1.9 mm. Our navigation system provides a clear image of the operation position and the surrounding structures. Systems like this may reduce intraoperative complications.

  4. A Microscopic Optically Tracking Navigation System That Uses High-resolution 3D Computer Graphics

    PubMed Central

    YOSHINO, Masanori; SAITO, Toki; KIN, Taichi; NAKAGAWA, Daichi; NAKATOMI, Hirofumi; OYAMA, Hiroshi; SAITO, Nobuhito

    2015-01-01

    Three-dimensional (3D) computer graphics (CG) are useful for preoperative planning of neurosurgical operations. However, application of 3D CG to intraoperative navigation is not widespread because existing commercial operative navigation systems do not show 3D CG in sufficient detail. We have developed a microscopic optically tracking navigation system that uses high-resolution 3D CG. This article presents the technical details of our microscopic optically tracking navigation system. Our navigation system consists of three components: the operative microscope, registration, and the image display system. An optical tracker was attached to the microscope to monitor the position and attitude of the microscope in real time; point-pair registration was used to register the operation room coordinate system, and the image coordinate system; and the image display system showed the 3D CG image in the field-of-view of the microscope. Ten neurosurgeons (seven males, two females; mean age 32.9 years) participated in an experiment to assess the accuracy of this system using a phantom model. Accuracy of our system was compared with the commercial system. The 3D CG provided by the navigation system coincided well with the operative scene under the microscope. Target registration error for our system was 2.9 ± 1.9 mm. Our navigation system provides a clear image of the operation position and the surrounding structures. Systems like this may reduce intraoperative complications. PMID:26226982

  5. A sample holder with integrated laser optics for an ELMITEC photoemission electron microscope

    SciTech Connect

    Gierster, L.; Pape, L.; Ünal, A. A.; Kronast, F.

    2015-02-15

    We present a new sample holder compatible with ELMITEC Photoemission Electron Microscopes (PEEMs) containing an optical lens and a mirror. With the integrated optical elements, a laser beam is focused from the back side of the sample at normal incidence, yielding a minimum spot size of about 1 μm. This opens up new possibilities for local laser excitations in PEEM experiments such as imaging all-optical magnetization switching at a small length scale.

  6. A sample holder with integrated laser optics for an ELMITEC photoemission electron microscope.

    PubMed

    Gierster, L; Pape, L; Ünal, A A; Kronast, F

    2015-02-01

    We present a new sample holder compatible with ELMITEC Photoemission Electron Microscopes (PEEMs) containing an optical lens and a mirror. With the integrated optical elements, a laser beam is focused from the back side of the sample at normal incidence, yielding a minimum spot size of about 1 μm. This opens up new possibilities for local laser excitations in PEEM experiments such as imaging all-optical magnetization switching at a small length scale.

  7. A microscopic steam engine implemented in an optical tweezer

    NASA Astrophysics Data System (ADS)

    Quinto-Su, Pedro A.

    2014-12-01

    The introduction of improved steam engines at the end of the 18th century marked the start of the industrial revolution and the birth of classical thermodynamics. Currently, there is great interest in miniaturizing heat engines, but so far traditional heat engines operating with the expansion and compression of gas have not reached length scales shorter than one millimeter. Here, a micrometer-sized piston steam engine is implemented in an optical tweezer. The piston is a single colloidal microparticle that is driven by explosive vapourization of the surrounding liquid (cavitation bubbles) and by optical forces at a rate between a few tens of Hertz and one kilo-Hertz. The operation of the engine allows to exert impulsive forces with optical tweezers and induce streaming in the liquid, similar to the effect of transducers when driven at acoustic and ultrasound frequencies.

  8. A microscopic steam engine implemented in an optical tweezer.

    PubMed

    Quinto-Su, Pedro A

    2014-12-19

    The introduction of improved steam engines at the end of the 18th century marked the start of the industrial revolution and the birth of classical thermodynamics. Currently, there is great interest in miniaturizing heat engines, but so far traditional heat engines operating with the expansion and compression of gas have not reached length scales shorter than one millimeter. Here, a micrometer-sized piston steam engine is implemented in an optical tweezer. The piston is a single colloidal microparticle that is driven by explosive vapourization of the surrounding liquid (cavitation bubbles) and by optical forces at a rate between a few tens of Hertz and one kilo-Hertz. The operation of the engine allows to exert impulsive forces with optical tweezers and induce streaming in the liquid, similar to the effect of transducers when driven at acoustic and ultrasound frequencies.

  9. [Development of slit-lamp microscope and its applications in optics].

    PubMed

    Qi, Haohui

    2013-11-01

    This paper mainly introduces the origin and development of the slit-lamp microscope, the basic structure, working principle and test methods, focuses on diffuse illumination, direct focal illumination, indirect illumination, retro illumination, zone of specular reflection and slit-lamp filter used in the optical inspection, to provide the reference for clinical general optometry practitioners and using slit-lamp microscope widely and standardized.

  10. Single-pulse CARS based multimodal nonlinear optical microscope for bioimaging.

    PubMed

    Kumar, Sunil; Kamali, Tschackad; Levitte, Jonathan M; Katz, Ori; Hermann, Boris; Werkmeister, Rene; Považay, Boris; Drexler, Wolfgang; Unterhuber, Angelika; Silberberg, Yaron

    2015-05-18

    Noninvasive label-free imaging of biological systems raises demand not only for high-speed three-dimensional prescreening of morphology over a wide-field of view but also it seeks to extract the microscopic functional and molecular details within. Capitalizing on the unique advantages brought out by different nonlinear optical effects, a multimodal nonlinear optical microscope can be a powerful tool for bioimaging. Bringing together the intensity-dependent contrast mechanisms via second harmonic generation, third harmonic generation and four-wave mixing for structural-sensitive imaging, and single-beam/single-pulse coherent anti-Stokes Raman scattering technique for chemical sensitive imaging in the finger-print region, we have developed a simple and nearly alignment-free multimodal nonlinear optical microscope that is based on a single wide-band Ti:Sapphire femtosecond pulse laser source. Successful imaging tests have been realized on two exemplary biological samples, a canine femur bone and collagen fibrils harvested from a rat tail. Since the ultra-broad band-width femtosecond laser is a suitable source for performing high-resolution optical coherence tomography, a wide-field optical coherence tomography arm can be easily incorporated into the presented multimodal microscope making it a versatile optical imaging tool for noninvasive label-free bioimaging.

  11. Comparisons between conventional optical imaging and parametric indirect microscopic imaging on human skin detection

    NASA Astrophysics Data System (ADS)

    Liu, Guoyan; Gao, Kun; Liu, Xuefeng; Ni, Guoqiang

    2016-10-01

    We report a new method, polarization parameters indirect microscopic imaging with a high transmission infrared light source, to detect the morphology and component of human skin. A conventional reflection microscopic system is used as the basic optical system, into which a polarization-modulation mechanics is inserted and a high transmission infrared light source is utilized. The near-field structural characteristics of human skin can be delivered by infrared waves and material coupling. According to coupling and conduction physics, changes of the optical wave parameters can be calculated and curves of the intensity of the image can be obtained. By analyzing the near-field polarization parameters in nanoscale, we can finally get the inversion images of human skin. Compared with the conventional direct optical microscope, this method can break diffraction limit and achieve a super resolution of sub-100nm. Besides, the method is more sensitive to the edges, wrinkles, boundaries and impurity particles.

  12. The standardization of super resolution optical microscopic images based on DICOM

    NASA Astrophysics Data System (ADS)

    Xia, Wei; Gao, Xin

    2015-03-01

    Super resolution optical microscopy allows the capture of images with a higher resolution than the diffraction limit. However, due to the lack of a standard format, the processing, visualization, transfer, and exchange of Super Resolution Optical Microscope (SROM) images are inconvenient. In this work, we present an approach to standardize the SROM images based on the Digital Imaging and Communication in Medicine (DICOM) standard. The SROM images and associated information are encapsulated and converted to DICOM images based on the Visible Light Microscopic Image Information Object Definition of DICOM. The new generated SROM images in DICOM format can be displayed, processed, transferred, and exchanged by using most medical image processing tools.

  13. Ultrafast chirped optical waveform recorder using a time microscope

    SciTech Connect

    Bennett, Corey Vincent

    2015-04-21

    A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

  14. Observation of Amorphous Recording Marks Using Reflection-Mode Near-Field Scanning Optical Microscope Supported by Optical Interference Method

    NASA Astrophysics Data System (ADS)

    Sakai, Masaru; Mononobe, Shuji; Yusu, Keiichiro; Tadokoro, Toshiyasu; Saiki, Toshiharu

    2005-09-01

    A signal enhancing technique for a reflection-mode near-field scanning optical microscope (NSOM) is proposed. Optical interference between the signal light, from an aperture at the tip of a tapered optical fiber, and the reflected light, from a metallic coating around the aperture, enhances the signal intensity. We used a rewritable high-definition digital versatile disc (HD DVD) with dual recording layers as a sample medium, and demonstrated observation of amorphous recording marks on the semitransparent (the first) recording layer. In spite of low optical contrast between the crystal region and the amorphous region on this layer, we successfully observed recording marks with good contrast.

  15. Mechanism for improving the signal-to-noise ratio in scanning optical microscopes

    NASA Astrophysics Data System (ADS)

    Milster, Tom D.; Walker, Edwin P.

    1996-08-01

    We demonstrate an improved signal-to-noise ratio in a scanning optical microscope used to read out information from a magneto-optical data storage layer. By placing a shading band in the return path of the optical system we can reduce noise by as much as 3 dB in certain spatial frequency ranges. The signal-to-noise ratio improvement arises from differences in the signal and noise distributions in the pupil of the optical system. Although the experimental results are shown only in one dimension, the concept is applicable to two-dimensional scanning of low-contrast samples.

  16. Multi-modal miniaturized microscope: successful merger of optical, MEMS, and electronic technologies

    NASA Astrophysics Data System (ADS)

    Tkaczyk, Tomasz S.; Rogers, Jeremy D.; Rahman, Mohammed; Christenson, Todd C.; Gaalema, Stephen; Dereniak, Eustace L.; Richards-Kortum, Rebecca; Descour, Michael R.

    2005-12-01

    The multi-modal miniature microscope (4M) device for early cancer detection is based on micro-optical table (MOT) platform which accommodates on a chip: optical, micro-mechanical, and electronic components. The MOT is a zeroalignment optical-system concept developed for a wide variety of opto-mechanical instruments. In practical terms this concept translates into assembly errors that are smaller than the tolerances on the performance of the optical system. This paper discusses all major system elements: optical system, custom high speed CMOS detector and comb drive actuator. It also points to mutual relations between different technologies. The hybrid sol-gel lenses, their fabrication and assembling techniques, optical system parameters, and various operation modes are also discussed. A particularly interesting mode is a structured illumination technique that delivers confocal-imaging capabilities and may be used for optical sectioning. Structured illumination is produced with LIGA fabricated actuator scanning in resonance and reconstructed using sine approximation algorithm.

  17. Chamber for the optical manipulation of microscopic particles

    DOEpatents

    Buican, Tudor N.; Upham, Bryan D.

    1992-01-01

    A particle control chamber enables experiments to be carried out on biological cells and the like using a laser system to trap and manipulate the particles. A manipulation chamber provides a plurality of inlet and outlet ports for the particles and for fluids used to control or to contact the particles. A central manipulation area is optically accessible by the laser and includes first enlarged volumes for containing a selected number of particles for experimentation. A number of first enlarged volumes are connected by flow channels through second enlarged volumes. The second enlarged volumes act as bubble valves for controlling the interconnections between the first enlarged volumes. Electrode surfaces may be applied above the first enlarged volumes to enable experimentation using the application of electric fields within the first enlarged volumes. A variety of chemical and environmental conditions may be established within individual first enlarged volumes to enable experimental conditions for small scale cellular interactions.

  18. Novel microscope-integrated stereoscopic heads-up display for intrasurgical optical coherence tomography

    PubMed Central

    Shen, Liangbo; Carrasco-Zevallos, Oscar; Keller, Brenton; Viehland, Christian; Waterman, Gar; Hahn, Paul S.; Kuo, Anthony N.; Toth, Cynthia A.; Izatt, Joseph A.

    2016-01-01

    Intra-operative optical coherence tomography (OCT) requires a display technology which allows surgeons to visualize OCT data without disrupting surgery. Previous research and commercial intrasurgical OCT systems have integrated heads-up display (HUD) systems into surgical microscopes to provide monoscopic viewing of OCT data through one microscope ocular. To take full advantage of our previously reported real-time volumetric microscope-integrated OCT (4D MIOCT) system, we describe a stereoscopic HUD which projects a stereo pair of OCT volume renderings into both oculars simultaneously. The stereoscopic HUD uses a novel optical design employing spatial multiplexing to project dual OCT volume renderings utilizing a single micro-display. The optical performance of the surgical microscope with the HUD was quantitatively characterized and the addition of the HUD was found not to substantially effect the resolution, field of view, or pincushion distortion of the operating microscope. In a pilot depth perception subject study, five ophthalmic surgeons completed a pre-set dexterity task with 50.0% (SD = 37.3%) higher success rate and in 35.0% (SD = 24.8%) less time on average with stereoscopic OCT vision compared to monoscopic OCT vision. Preliminary experience using the HUD in 40 vitreo-retinal human surgeries by five ophthalmic surgeons is reported, in which all surgeons reported that the HUD did not alter their normal view of surgery and that live surgical maneuvers were readily visible in displayed stereoscopic OCT volumes. PMID:27231616

  19. Novel microscope-integrated stereoscopic heads-up display for intrasurgical optical coherence tomography.

    PubMed

    Shen, Liangbo; Carrasco-Zevallos, Oscar; Keller, Brenton; Viehland, Christian; Waterman, Gar; Hahn, Paul S; Kuo, Anthony N; Toth, Cynthia A; Izatt, Joseph A

    2016-05-01

    Intra-operative optical coherence tomography (OCT) requires a display technology which allows surgeons to visualize OCT data without disrupting surgery. Previous research and commercial intrasurgical OCT systems have integrated heads-up display (HUD) systems into surgical microscopes to provide monoscopic viewing of OCT data through one microscope ocular. To take full advantage of our previously reported real-time volumetric microscope-integrated OCT (4D MIOCT) system, we describe a stereoscopic HUD which projects a stereo pair of OCT volume renderings into both oculars simultaneously. The stereoscopic HUD uses a novel optical design employing spatial multiplexing to project dual OCT volume renderings utilizing a single micro-display. The optical performance of the surgical microscope with the HUD was quantitatively characterized and the addition of the HUD was found not to substantially effect the resolution, field of view, or pincushion distortion of the operating microscope. In a pilot depth perception subject study, five ophthalmic surgeons completed a pre-set dexterity task with 50.0% (SD = 37.3%) higher success rate and in 35.0% (SD = 24.8%) less time on average with stereoscopic OCT vision compared to monoscopic OCT vision. Preliminary experience using the HUD in 40 vitreo-retinal human surgeries by five ophthalmic surgeons is reported, in which all surgeons reported that the HUD did not alter their normal view of surgery and that live surgical maneuvers were readily visible in displayed stereoscopic OCT volumes.

  20. Regenerative Fourier transformation for dual-quadrature regeneration of multilevel rectangular QAM.

    PubMed

    Sorokina, Mariia; Sygletos, Stylianos; Ellis, Andrew; Turitsyn, Sergei

    2015-07-01

    We propose a new nonlinear optical loop mirror based configuration capable of regenerating regular rectangular quadrature amplitude modulated (QAM) signals. The scheme achieves suppression of noise distortion on both signal quadratures through the realization of two orthogonal regenerative Fourier transformations. Numerical simulations show the performance of the scheme for high constellation complexities (including 256-QAM formats).

  1. Development of a super-resolution optical microscope for directional dark matter search experiment

    NASA Astrophysics Data System (ADS)

    Alexandrov, A.; Asada, T.; Consiglio, L.; D`Ambrosio, N.; De Lellis, G.; Di Crescenzo, A.; Di Marco, N.; Furuya, S.; Hakamata, K.; Ishikawa, M.; Katsuragawa, T.; Kuwabara, K.; Machii, S.; Naka, T.; Pupilli, F.; Sirignano, C.; Tawara, Y.; Tioukov, V.; Umemoto, A.; Yoshimoto, M.

    2016-07-01

    Nuclear emulsion is a perfect choice for a detector for directional DM search because of its high density and excellent position accuracy. The minimal detectable track length of a recoil nucleus in emulsion is required to be at least 100 nm, making the resolution of conventional optical microscopes insufficient to resolve them. Here we report about the R&D on a super-resolution optical microscope to be used in future directional DM search experiments with nuclear emulsion as a detector media. The microscope will be fully automatic, will use novel image acquisition and analysis techniques, will achieve the spatial resolution of the order of few tens of nm and will be capable of reconstructing recoil tracks with the length of at least 100 nm with high angular resolution.

  2. Development of hard X-ray dark-field microscope using full-field optics

    NASA Astrophysics Data System (ADS)

    Takano, Hidekazu; Azuma, Hiroaki; Shimomura, Sho; Tsuji, Takuya; Tsusaka, Yoshiyuki; Kagoshima, Yasushi

    2016-10-01

    We develop a dark-field X-ray microscope using full-field optics based on a synchrotron beamline. Our setup consists of a condenser system and a microscope objective with an angular acceptance larger than that of the condenser. The condenser system is moved downstream from its regular position such that the focus of the condenser is behind the objective. The dark-field microscope optics are configured by excluding the converging beam from the condenser at the focal point. The image properties of the system are evaluated by observing and calculating a Siemens star test chart with 10 keV X-rays. Our setup allows easy switching to bright-field imaging.

  3. Acousto-Optic Tunable Filter Hyperspectral Microscope Imaging Method for Characterizing Spectra from Foodborne Pathogens.

    USDA-ARS?s Scientific Manuscript database

    Hyperspectral microscope imaging (HMI) method, which provides both spatial and spectral characteristics of samples, can be effective for foodborne pathogen detection. The acousto-optic tunable filter (AOTF)-based HMI method can be used to characterize spectral properties of biofilms formed by Salmon...

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

    PubMed

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

    2010-06-01

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

  5. High spatial resolution absorption contrast imaging with electron-beam excitation assisted optical microscope

    NASA Astrophysics Data System (ADS)

    Inami, Wataru; Fukuta, Masahiro; Kawata, Yoshimasa; Terakawa, Susumu

    2016-11-01

    We present high spatial-resolution label-free imaging with an electron-beam excitation-assisted optical microscope (EXA microscope). The EXA microscope improves the spatial resolution down to 100 nm. To realize the high spatial resolution, a nanoscale optical spot is generated by irradiating a fluorescent thin film with a focused electron beam whose spot size is less than 10 nm. The size of the optical spot becomes smaller than the diffraction limited spot size and is reduced to about 100 nm, because the light emission is localized in nanometer-sized region. In this microscopy, it is not necessary to label a specimen for imaging beyond the diffraction limit of the light. The specimen stage is separated from the vacuum chamber of the scanning electron microscope by the fluorescent thin film and a specimen under atmospheric pressure can be imaged. We demonstrated that the high spatial resolution absorption contrast imaging of the crystal of vitamin B9 having absorption at UV wavelengths. The absorption wavelength matches with the wavelength of the emission of the fluorescent thin film we deposited. The fine crystal structure was imaged beyond the optical diffraction limit. The image contrast corresponded with the thickness of the crystal measured with an atomic force microscope (AFM). The illumination light is absorbed with the vitamin B9 crystal and the intensity of the transmitted light depends on the thickness of the vitamin B9 crystal. The EXA microscope is useful for analysis of growth of a crystal, bio-imaging, and so on.

  6. A method to determine the number of nanoparticles in a cluster using conventional optical microscopes

    SciTech Connect

    Kang, Hyeonggon; Attota, Ravikiran Tondare, Vipin; Vladár, András E.; Kavuri, Premsagar

    2015-09-07

    We present a method that uses conventional optical microscopes to determine the number of nanoparticles in a cluster, which is typically not possible using traditional image-based optical methods due to the diffraction limit. The method, called through-focus scanning optical microscopy (TSOM), uses a series of optical images taken at varying focus levels to achieve this. The optical images cannot directly resolve the individual nanoparticles, but contain information related to the number of particles. The TSOM method makes use of this information to determine the number of nanoparticles in a cluster. Initial good agreement between the simulations and the measurements is also presented. The TSOM method can be applied to fluorescent and non-fluorescent as well as metallic and non-metallic nano-scale materials, including soft materials, making it attractive for tag-less, high-speed, optical analysis of nanoparticles down to 45 nm diameter.

  7. The construction and characterization of optical traps for manipulating microscopic particles

    NASA Astrophysics Data System (ADS)

    Thompson, Tiffany; Behringer, Ernest

    2011-04-01

    Optical traps use tightly focused laser light to manipulate microscopic particles and have applications in nanofabrication, characterizing DNA, and in vitro fertilization [1]. We will describe the design, construction, and characterization of an optical trap that is capable of trapping and imaging 3 μm polystyrene spheres using a 12 mW HeNe laser. The design was based on previous work [2,3] describing how to build affordable optical traps. We will discuss trapping forces and their calibration. [4pt] [1] D.G. Grier, "A Revolution in Optical Manipulation," Nature 424, 810-816 (2003). [0pt] [2] S.P. Smith et al., "Inexpensive optical tweezers for undergraduate laboratories," Am. J. Phys. 67 (1), 26-35 (1999).[0pt] [3] J. Bechhoefer et al., "Faster, cheaper, safer optical tweezers for the undergraduate laboratory," Am. J. Phys. 70 (4), 393-400 (2001).

  8. The development of an adaptive optics system and its application to biological microscope

    NASA Astrophysics Data System (ADS)

    Hattori, Masayuki; Tamada, Yosuke

    2016-10-01

    The improvement of the optical devices in this decade, such as the MEMS-SLM ( Micro Electro Mechanical Systems- Spatial Light Modulator ) and wave front sensor with micro lens device, is making adaptive optics commonly available. It also gives the new basis of the design of adaptive optics with the improved accuracy and the compactness. We have developed an adaptive optics bench from such a point of view, and the application to the optical microscope has attained effective results in the observation of the live cell samples. In this presentation, our recent results will be shown. The result includes analysis of blur by the fine structures in biological sample and result of the image correction by the adaptive optics.

  9. Scanning near-field optical microscope working with a CdSe /ZnS quantum dot based optical detector

    NASA Astrophysics Data System (ADS)

    Aigouy, L.; Samson, B.; Julié, G.; Mathet, V.; Lequeux, N.; Nı. Allen, C.; Diaf, H.; Dubertret, B.

    2006-06-01

    We have developed a scanning near-field optical microscope that uses a subwavelength-sized silica sphere covered with CdSe /ZnS quantum dots as a fluorescent optical detector. Due to the good photostability of these semiconducting particles, we are routinely able to perform several successive scans without a noticeable decrease of fluorescence signals. As an example, we will show some images of the light immediately transmitted through 300nm wide slits made in a thin gold film. We will also discuss the advantages of such fluorescent probes compared to other near-field optical techniques.

  10. Detection of Luminescent Nanodiamonds Using a Scanning Near-Field Optical Microscope with an Aperture Probe

    NASA Astrophysics Data System (ADS)

    Shershulin, V. A.; Samoylenko, S. R.; Shenderova, O. A.; Vlasov, I. I.; Konov, V. I.

    2016-09-01

    Scanning near-fi eld optical microscopy (SNOM) with an aperture probe has been used to map the luminescence of isolated submicron diamond crystallites. 532-nm laser light was used to excite luminescence of nitrogen-vacancy (NV) centers. The sizes of the analyzed diamond crystallites were determined with an atomic-force microscope. The optical resolution for the lateral dimensions of the luminescing diamond crystallites was doubled on going from confocal luminescence microscopy to scanning near-fi eld optical microscopy with a 290-nm probe aperture diameter.

  11. An Auto-Focusing Method in a Microscopic Testbed for Optical Discs.

    PubMed

    Tang, X; L'Hostis, P; Xiao, Y

    2000-01-01

    An auto-focusing method in a digital image system is demonstrated that uses a standard deviation of pixel gray levels as a feedback signal. In this system, an optical microscope and a charge coupled device (CCD) camera are used to create clear pit images of optical discs. A dynamic focusing scheme is designed in the system-control software, which is able to eliminate environmental disturbances and other noises so that a fast and stable focus can be achieved. The method shows an excellent focusing accuracy. The performance and possible applications of this method are discussed. The test results for optical discs are given in this paper.

  12. Iterative deconvolution technique for measurements of diffraction-limited images on optical microscopes.

    PubMed

    Lu, Wenlong; Chang, Ming; Chen, Po-Cheng; Luo, Wun-Mao

    2014-12-12

    Diffraction limit is usually a thorny problem in an optical inspection system. In this investigation, a model-based deconvolution technique was developed to recover diffraction-limited images, where images with sizes smaller than the diffraction limit could be recognized. Experiments were carried out with a traditional microscope at 200× magnification coupled with a halogen light source for a series of line width samples. The point spread function of the imaging optics was first obtained from an estimated model and then combined with a nonlinear deconvolution algorithm to calculate the full width at half maximum and reconstruct the line widths. Experimental results indicate that a measurement error below one pixel size of the measurement system is achievable. Accordingly, the target of nanoscale line width inspection based on a low cost and real-time image processing technique can be fulfilled, which greatly increases the ability of nanoscaling on optical microscopes.

  13. Efficient loading of a single neutral atom into an optical microscopic tweezer

    NASA Astrophysics Data System (ADS)

    He, Jun; Liu, Bei; Diao, Wen-Ting; Wang, Jie-Ying; Jin, Gang; Wang, Jun-Min

    2015-04-01

    A single atom in a magneto-optical trap (MOT) with trap size (hundreds of micrometers) can be transferred into an optical microscopic tweezer with a probability of ~ 100%. The ability to transfer a single atom into two traps back and forth allows us to study the loading process. The loading probability is found to be insensitive to the geometric overlap of the MOT and the tweezer. It is therefore possible to perform simultaneously loading of a single atom into all sites of the tweezer array for many qubits. In particular, we present a simulation of the one-dimensional and two-dimensional arrays of an optical microscopic tweezer. We find the same qualitative behavior for all of the trap parameters. Project supported by the National Major Scientific Research Program of China (Grant No. 2012CB921601) and the National Natural Science Foundation of China (Grant Nos. 61205215, 11274213, and 61475091).

  14. Apertureless near-field scanning optical microscope working with or without laser source.

    PubMed

    Formanek, F; De Wilde, Y; Aigouy, L; Chen, Y

    2004-01-01

    An apertureless near-field scanning optical microscope (ANSOM), used indifferent configurations, is presented. Our versatile home-made setup, based on a sharp tungsten tip glued onto a quartz tuning fork and working in tapping mode, allows to perform imaging over a broad spectral range. We have recorded optical images in the visible (wavelength, lambda = 655 nm) and in the infrared (lambda = 10.6 microm), proving that the setup routinely achieves an optical resolution of <50 nm regardless of the illumination wavelength. We have also shown optical images recorded in the visible (lambda = 655 nm) in an inverted configuration where the tip does not perturb the focused spot of the illumination laser. Approach curves as well as image profiles have revealed that on demodulating the optical signal at higher harmonics, we can obtain an effective probe sharpening which results in an improvement of the resolution. Finally, we have presented optical images recorded in the infrared without any illumination, that is, the usual laser source is replaced by a simple heating of the sample. This has shown that the ANSOM can be used as a near-field thermal optical microscope (NTOM) to probe the near field generated by the thermal emission of the sample.

  15. Low Temperature Apertureless Near-field Scanning Optical Microscope for Optical Spectroscopy of Single Ge/Si Quantum Dots

    NASA Astrophysics Data System (ADS)

    Zhu, Henry; Patil, N. G.; Levy, Jeremy

    2001-03-01

    A low-temperature apertureless near-field scanning optical microscope has been designed and constructed for the purpose of investigating the optical properties of individual Ge/Si quantum dots. The microscope fits in the 37 mm bore of a Helium vapor magneto-optic cryostat, allowing operations down to liquid helium temperatures in magnetic fields up to 8 Tesla. An in situ microscope objective focuses light onto the sample, which is scanned in the three spatial directions using a compact modular stage. An AFM/STM tip resides on the top; feedback is achieved using a quartz tuning fork oscillator. Both tip and objective are attached to inertial sliding motors that can move in fine (10 nm) steps to achieve touchdown and focus. A femtosecond optical parametric oscillator is used to excite carriers in the quantum dots both resonantly and non-resonantly; scattered luminescence from the AFM/STM tip is collected and analyzed spectrally using a 1/2 meter imaging spectrometer and a LN_2-cooled InGaAs array. We gratefully acknowledge NSF (DMR-9701725, IMR-9802784) and DARPA (DAAD-16-99-C1036) for financial support of this work.

  16. Refinements of some new efficient quadrature rules

    NASA Astrophysics Data System (ADS)

    Qayyum, A.; Shoaib, M.; Faye, I.; Kashif, A. R.

    2016-11-01

    In the field of Engineering and Applied Mathematical Sciences, minimizing approximation error is very important task and therefore quadrature rules are investigated regularly. In this paper, using some standard results of theoretical inequalities, e.g. Ostrowski type inequality, some new efficient quadrature rules are introduced for n-times differentiable mappings. These quadrature rules are expected to give better results comparing to the conventional quadrature rules.

  17. Development of a Near-Field Scanning Optical Microscope for Imaging Biological Samples in Physiological Buffer

    NASA Astrophysics Data System (ADS)

    Seibel, Eric Jeffrey

    A near-field scanning optical microscope was constructed for imaging intact biological samples in physiological buffer at a resolution beyond the optical diffraction limit. Images are formed by raster scanning the sample within the near -field of the optical probe, which emits collimated light for a limited distance. The technical challenges that were encountered were making the probe, micropositioning the probe and sample with piezoelectrics, and maintaining the sample-probe separation to within the near-field ( <200 nm). By recording the measurement of probe-sample separation during a scan, a topographic image is generated simultaneously with the near-field optical image. The microscope having both imaging modalities was tested and judged fully operational by imaging fluorescently -labeled microspheres under water. The potential of near-field scanning optical microscopy for future biological research was investigated by imaging a fluorescently-labeled, biological test specimen, the single myofibril. Imaging the intact myofibril in buffered saline without chemical fixation provides a challenging, practical test for the microscope. Near-field fluorescence and topographic images of single myofibrils produced image resolution of <=q300 nm, versus ~500 nm for conventional optical microscopy. Interpretation of the images is facilitated by the protein-specific fluorescence labeling. Increasing sample thickness degrades the resolution of the fluorescence images only. Thus, biological samples having > 1 μm thickness, are the practical limit of sample thickness for generating high resolution near-field optical images, when fluorescence is collected in transmission. In contrast, the method of generating the topographic images (called lateral shear-force microscopy), has the advantage of being insensitive to sample thickness. In the topographic images of myofibrils, the change in topography and/or stiffness from the binding of antibodies was detected. The results of this

  18. Aerosol dynamics using the quadrature method of moments: comparing several quadrature schemes with particle-resolved simulation

    NASA Astrophysics Data System (ADS)

    McGraw, R.; Leng, L.; Zhu, W.; Riemer, N.; West, M.

    2008-07-01

    The method of moments (MOM) is a statistically based alternative to sectional and modal methods for aerosol simulation. The MOM is highly efficient as the aerosol distribution is represented by its lower-order moments and only these, not the full distribution itself, are tracked during simulation. Quadrature is introduced to close the moment equations under very general growth laws and to compute aerosol physical and optical properties directly from moments. In this paper the quadrature method of moments (QMOM) is used in a bivariate test tracking of aerosol mixing state. Two aerosol populations, one enriched in soot and the other in sulfate, are allowed to interact through coagulation to form a generally-mixed third particle population. Quadratures of varying complexity (including two candidate schemes for use in climate models) are described and compared with benchmark results obtained by using particle-resolved simulation. Low-order quadratures are found to be highly accurate, and Gauss and Gauss-Radau quadratures appear to give nested lower and upper bounds, respectively, to aerosol mixing rate. These results suggest that the QMOM makes it feasible to represent the generallymixed states of aerosols and track their evolution in climate models.

  19. The Development of a Heated-Stage Optical Microscope for ZBLAN Microgravity Crystallization Studies

    NASA Astrophysics Data System (ADS)

    Torres, Anthony; Barr, Reuben

    2016-08-01

    A heated-stage optical microscope has been developed for in-situ crystallization observation of ZBLAN glass. Traditional crystallization studies on most materials, including ZBLAN, are completed following high temperature heat treatment. The modern heated-stage microscope developed in this study permits high temperature sample microscopy data to be collected in real time. The heated stage has a high-end temperature limit of 520 ∘C with a heating ramp rate of 2.2 ∘C/second. The stage was also fitted with liquid nitrogen for rapid cooling and sample annealing up to -190 ∘C. The stage was customized to fit a Keyence VHX-2000 digital microscope with a magnification range of 100X-1000X. The microscope also has the ability to image samples using Differential Interference Contrasts (DIC) microscopy, which is used to elucidate key crystalline features not apparent with traditional optical microscopy. Additionally, the experiment was constructed to be operated on a microgravity parabolic aircraft to study the effects of microgravity on the crystallization of ZBLAN.

  20. First-order optical analysis of a quasi-microscope for planetary landers

    NASA Technical Reports Server (NTRS)

    Huck, F. O.; Sinclair, A. R.; Burcher, E. E.

    1973-01-01

    A first-order geometrical optics analysis of a facsimile camera augmented with an auxiliary lens as magnifier is presented. This concept, called quasi-microscope, bridges the gap between surface resolutions of the order of 1 to 10 mm which can be obtained directly with planetary lander cameras and resolutions of the order of 0.2 to 10 microns which can be obtained only with relatively complex microscopes. A facsimile camera was considered in the analysis; however, the analytical results can also be applied to television and film cameras. It was found that quasi-microscope resolutions in the range from 10 to 100 microns are obtainable with current state-of-the-art lander facsimile cameras. For the Viking lander camera having an angular resolution of 0.04 deg, which was considered as a specific example, the best achievable resolution would be about 20 microns. The preferred approach to increase the resolution of the quasi-microscope would be, if possible, through an increase in angular resolution of the camera. A twofold to threefold improvement in resolution could also be achieved with a special camera focus position, but this approach tends to require larger and heavier auxiliary optics.

  1. Programmable Colored Illumination Microscopy (PCIM): A practical and flexible optical staining approach for microscopic contrast enhancement

    NASA Astrophysics Data System (ADS)

    Zuo, Chao; Sun, Jiasong; Feng, Shijie; Hu, Yan; Chen, Qian

    2016-03-01

    Programmable colored illumination microscopy (PCIM) has been proposed as a flexible optical staining technique for microscopic contrast enhancement. In this method, we replace the condenser diaphragm of a conventional microscope with a programmable thin film transistor-liquid crystal display (TFT-LCD). By displaying different patterns on the LCD, numerous established imaging modalities can be realized, such as bright field, dark field, phase contrast, oblique illumination, and Rheinberg illuminations, which conventionally rely on intricate alterations in the respective microscope setups. Furthermore, the ease of modulating both the color and the intensity distribution at the aperture of the condenser opens the possibility to combine multiple microscopic techniques, or even realize completely new methods for optical color contrast staining, such as iridescent dark-field and iridescent phase-contrast imaging. The versatility and effectiveness of PCIM is demonstrated by imaging of several transparent colorless specimens, such as unstained lung cancer cells, diatom, textile fibers, and a cryosection of mouse kidney. Finally, the potentialities of PCIM for RGB-splitting imaging with stained samples are also explored by imaging stained red blood cells and a histological section.

  2. Construction of a high resolution microscope with conventional and holographic optical trapping capabilities.

    PubMed

    Butterfield, Jacqualine; Hong, Weili; Mershon, Leslie; Vershinin, Michael

    2013-04-22

    High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads (1) or cellular organelles (2,3), as well as for high spatial and temporal resolution readout of their position relative to the center of the trap. The system described herein has one such "traditional" trap operating at 980 nm. It additionally provides a second optical trapping system that uses a commercially available holographic package to simultaneously create and manipulate complex trapping patterns in the field of view of the microscope (4,5) at a wavelength of 1,064 nm. The combination of the two systems allows for the manipulation of multiple refractive objects at the same time while simultaneously conducting high speed and high resolution measurements of motion and force production at nanometer and piconewton scale.

  3. Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities

    PubMed Central

    Butterfield, Jacqualine; Hong, Weili; Mershon, Leslie; Vershinin, Michael

    2013-01-01

    High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular organelles 2,3, as well as for high spatial and temporal resolution readout of their position relative to the center of the trap. The system described herein has one such "traditional" trap operating at 980 nm. It additionally provides a second optical trapping system that uses a commercially available holographic package to simultaneously create and manipulate complex trapping patterns in the field of view of the microscope 4,5 at a wavelength of 1,064 nm. The combination of the two systems allows for the manipulation of multiple refractive objects at the same time while simultaneously conducting high speed and high resolution measurements of motion and force production at nanometer and piconewton scale. PMID:23629580

  4. Fractal evaluation of drug amorphicity from optical and scanning electron microscope images

    NASA Astrophysics Data System (ADS)

    Gavriloaia, Bogdan-Mihai G.; Vizireanu, Radu C.; Neamtu, Catalin I.; Gavriloaia, Gheorghe V.

    2013-09-01

    Amorphous materials are metastable, more reactive than the crystalline ones, and have to be evaluated before pharmaceutical compound formulation. Amorphicity is interpreted as a spatial chaos, and patterns of molecular aggregates of dexamethasone, D, were investigated in this paper by using fractal dimension, FD. Images having three magnifications of D were taken from an optical microscope, OM, and with eight magnifications, from a scanning electron microscope, SEM, were analyzed. The average FD for pattern irregularities of OM images was 1.538, and about 1.692 for SEM images. The FDs of the two kinds of images are less sensitive of threshold level. 3D images were shown to illustrate dependence of FD of threshold and magnification level. As a result, optical image of single scale is enough to characterize the drug amorphicity. As a result, the OM image at a single scale is enough to characterize the amorphicity of D.

  5. Full-field transmission-type angle-deviation optical microscope with reflectivity-height transformation

    PubMed Central

    Chiu, Ming-Hung; Tan, Chen-Tai; Tsai, Ming-Hung; Yang, Ya-Hsin

    2015-01-01

    This full-field transmission-type three-dimensional (3D) optical microscope is constructed based on the angle deviation method (ADM) and the algorithm of reflectivity-height transformation (RHT). The surface height is proportional to the deviation angle of light passing through the object. The angle deviation and surface height can be measured based on the reflectivity closed to the critical angle using a parallelogram prism and two CCDs. PMID:26504645

  6. Full-field transmission-type angle-deviation optical microscope with reflectivity-height transformation.

    PubMed

    Chiu, Ming-Hung; Tan, Chen-Tai; Tsai, Ming-Hung; Yang, Ya-Hsin

    2015-10-01

    This full-field transmission-type three-dimensional (3D) optical microscope is constructed based on the angle deviation method (ADM) and the algorithm of reflectivity-height transformation (RHT). The surface height is proportional to the deviation angle of light passing through the object. The angle deviation and surface height can be measured based on the reflectivity closed to the critical angle using a parallelogram prism and two CCDs.

  7. Defect tracking for nanoimprint lithography using optical surface scanner and scanning electron microscope

    NASA Astrophysics Data System (ADS)

    Yu, Zhaoning; Kurataka, Nobuo; Tran, Hieu; Gauzner, Gene

    2016-09-01

    Fast optical surface scanners are used in combination with high-resolution scanning electron microscopes to facilitate the identification and tracking of nanoimprint defects. We have confirmed that hard particles cause permanent template damages during imprint, resulting in repeating imprint defects. Since contaminants encountered during imprint are dominated by hard metal oxide particles capable of causing such damage, stringent pre-imprint substrate screening is a critical requirement in a manufacturing environment.

  8. Optical vortex microscope with the simple phase object: theoretical model and its experimental verification

    NASA Astrophysics Data System (ADS)

    Popiołek-Masajada, Agnieszka; Masajada, Jan; Kurzynowski, Piotr

    2017-06-01

    In this work we consider a microscopic optical system in which the beam with an optical vortex illuminates the sample. The sample modifies the geometry of the vortex beam wavefront and the information about it is transferred into the detection plane. It is shown that the beam at the detection plane can be represented by two parts: non-disturbed vortex part and sample part. We propose and test a scheme for recovering the phase changes caused by sample inserted into the vortex beam. The numerical simulations are supported by the experimental work.

  9. Modelling the application of adaptive optics to wide-field microscope live imaging.

    PubMed

    Kam, Zvi; Kner, Peter; Agard, David; Sedat, John W

    2007-04-01

    Wide-field fluorescence microscopy is an essential tool in modern cell biology. Unfortunately the image quality of fluorescence microscopes is often significantly degraded due to aberrations that occur under normal imaging conditions. In this article, we examine the use of adaptive optics technology to dynamically correct these problems to achieve close to ideal diffraction limited performance. Simultaneously, this technology also allows ultra-rapid focusing without having to move either the stage or the objective lens. We perform optical simulations to demonstrate the degree of correction that can be achieved.

  10. Optical characterization of individual semiconductor nanostructures using a scanning tunneling microscope.

    PubMed

    Tsuruoka, Tohru; Ushioda, Sukekatsu

    2004-01-01

    By injecting low-energy minority carriers from the tip of a scanning tunneling microscope (STM) and analyzing the light emitted from the tip-sample gap of the STM, it is possible to study the optical and electronic properties of individual semiconductor nanostructures with an extremely high spatial resolution close to the atomic scale. This technique has been applied to investigate the transport properties of hot electrons injected into AlGaAs/GaAs quantum well structures and the optical properties of single self-assembled InAs/AlGaAs quantum dots. The physical principles, usefulness and future expectations of this novel technique are discussed.

  11. On the optical stability of high-resolution transmission electron microscopes.

    PubMed

    Barthel, J; Thust, A

    2013-11-01

    In the recent two decades the technique of high-resolution transmission electron microscopy experienced an unprecedented progress through the introduction of hardware aberration correctors and by the improvement of the achievable resolution to the sub-Ångström level. The important aspect that aberration correction at a given resolution requires also a well defined amount of optical stability has received little attention so far. Therefore we investigate the qualification of a variety of high-resolution electron microscopes to maintain an aberration corrected optical state in terms of an optical lifetime. We develop a comprehensive statistical framework for the estimation of the optical lifetime and find remarkably low values between tens of seconds and a couple of minutes. Probability curves are introduced, which inform the operator about the chance to work still in the fully aberration corrected state.

  12. Fabrication of optical multilayer for two-color phase plate in super-resolution microscope.

    PubMed

    Iketaki, Yoshinori; Kitagawa, Katsuichi; Hidaka, Kohjiro; Kato, Naoki; Hirabayashi, Akira; Bokor, Nandor

    2014-07-01

    In super-resolution microscopy based on fluorescence depletion, the two-color phase plate (TPP) is an indispensable optical element, which can independently control the phase shifts for two beams of different color, i.e., the pump and erase beams. By controlling a phase shift of the erase beam through the TPP, the erase beam can be modulated into a doughnut shape, while the pump beam maintains the initial Gaussian shape. To obtain a reliable optical multiplayer (ML) for the TPP, we designed a ML with only two optical layers by performing numerical optimization. The measured phase shifts generated by the fabricated ML using interferometry correspond to the design values. The beam profiles in the focal plane are also consistent with theoretical results. Although the fabricated ML consists of only two optical layers, the ML can provide a suitable phase modulation function for the TPP in a practical super-resolution microscope.

  13. Fabrication of optical multilayer for two-color phase plate in super-resolution microscope

    SciTech Connect

    Iketaki, Yoshinori; Kitagawa, Katsuichi; Hidaka, Kohjiro; Kato, Naoki; Hirabayashi, Akira; Bokor, Nandor

    2014-07-15

    In super-resolution microscopy based on fluorescence depletion, the two-color phase plate (TPP) is an indispensable optical element, which can independently control the phase shifts for two beams of different color, i.e., the pump and erase beams. By controlling a phase shift of the erase beam through the TPP, the erase beam can be modulated into a doughnut shape, while the pump beam maintains the initial Gaussian shape. To obtain a reliable optical multiplayer (ML) for the TPP, we designed a ML with only two optical layers by performing numerical optimization. The measured phase shifts generated by the fabricated ML using interferometry correspond to the design values. The beam profiles in the focal plane are also consistent with theoretical results. Although the fabricated ML consists of only two optical layers, the ML can provide a suitable phase modulation function for the TPP in a practical super-resolution microscope.

  14. Microscopic modeling of the effect of phonons on the optical properties of solid-state emitters

    NASA Astrophysics Data System (ADS)

    Norambuena, Ariel; Reyes, Sebastián A.; Mejía-Lopéz, José; Gali, Adam; Maze, Jerónimo R.

    2016-10-01

    Understanding the effect of vibrations in optically active nanosystems is crucial for successfully implementing applications in molecular-based electro-optical devices, quantum information communications, single photon sources, and fluorescent markers for biological measurements. Here, we present a first-principles microscopic description of the role of phonons on the isotopic shift presented in the optical emission spectrum associated to the negatively charged silicon-vacancy color center in diamond. We use the spin-boson model and estimate the electron-phonon interactions using a symmetrized molecular description of the electronic states and a force-constant model to describe molecular vibrations. Group theoretical arguments and dynamical symmetry breaking are presented in order to explain the optical properties of the zero-phonon line and the isotopic shift of the phonon sideband.

  15. Microscopic optical potential for exotic isotopes from chiral effective field theory

    NASA Astrophysics Data System (ADS)

    Holt, J. W.; Kaiser, N.; Miller, G. A.

    2016-06-01

    We compute the isospin-asymmetry dependence of microscopic optical model potentials from realistic chiral two- and three-body interactions over a range of resolution scales Λ ≃400 -500 MeV. We show that at moderate projectile energies, E =110 -200 MeV, the real isovector part of the optical potential changes sign, a phenomenon referred to as isospin inversion. We also extract the strength and energy dependence of the imaginary isovector optical potential and find no evidence for an analogous phenomenon over the range of energies, E ≤200 MeV, considered in the present work. Finally, we compute for the first time the leading (quadratic) corrections to the Lane parametrization for the isospin-asymmetry dependence of the optical potential and observe an enhanced importance at low scattering energies.

  16. Comparison of global phenomenological and microscopic optical potentials for nuclear data predictions

    SciTech Connect

    Cai, C. ); Shen, Q.; Zhuo, Y. )

    1991-10-01

    In this paper the chi-square ({chi}{sup 2}) values, which represent the degree of agreement between the calculated total, nonelastic, and differential elastic cross sections and their experimental values, are calculated for seven kinds of optical potentials: the phenomenological optimal optical potential (OOP) for a specific element, the global phenomenological optical potentials given by Becchetti and Greenlees (BGP) and by Varner et al. (CH86) for a large number of target nuclei, and the microscopic optical potentials based on conventional Skyrme force (SII and SIII), generalized Skyrme force (GS2), and modified Skyrme force (SKa). Fourteen natural elements (each containing one to four isotopes) are calculated with 12 to 20 neutron incident energies, which are in the 0.1- to 24-MeV energy region for each element. The calculated average total chi-square values are {bar {chi}}{sub OOP}{sup 2} - 0.309, {bar {chi}}{sub BGP}{sup 2} = 0.807, {bar {chi}}{sub CH86}{sup 2} = 0.684, {bar {chi}}{sub GS2}{sup 2} = 0.600, {bar {chi}}{sub SKa}{sup 2} = 0.646, {bar {chi}}{sub SII}{sup 2} = 2.587, and {bar {chi}}{sub SIII}{sup 2} = 1.368. The conclusion is that the microscopic optical potential based on generalized and modified Skyrme force (GS2 and SKa), which has an analytical formalism without any free parameters, is useful in nuclear data calculation and evaluation.

  17. A self-adaptive and nonmechanical motion autofocusing system for optical microscopes.

    PubMed

    Qu, Yufu; Zhu, Shenyu; Zhang, Ping

    2016-11-01

    For the design of a passive autofocusing (AF) system for optical microscopes, many time-consuming and tedious experiments have been performed to determine and design a better focus criterion function, owing to the sample-dependence of this function. To accelerate the development of the AF systems in optical microscopes and to increase AF speed as well as maintain the AF accuracy, this study proposes a self-adaptive and nonmechanical motion AF system. The presented AF system does not require the selection and design of a focus criterion function when it is developed. Instead, the system can automatically determine a better focus criterion function for an observed sample by analyzing the texture features of the sample and subsequently perform an AF procedure to bring the sample into focus in the objective of an optical microscope. In addition, to increase the AF speed, the Z axis scanning of the mechanical motion of the sample or the objective is replaced by focusing scanning performed by a liquid lens, which is driven by an electrical current and does not involve mechanical motion. Experiments show that the reproducibility of the results obtained with the proposed self-adaptive and nonmechanical motion AF system is better than that provided by that of traditional AF systems, and that the AF speed is 10 times faster than that of traditional AF systems. Also, the self-adaptive function increased the speed of AF process by an average of 10.5% than Laplacian and Tenegrad functions.

  18. Microscope Integrated Intraoperative Spectral Domain Optical Coherence Tomography for Cataract Surgery: Uses and Applications.

    PubMed

    Das, Sudeep; Kummelil, Mathew Kurian; Kharbanda, Varun; Arora, Vishal; Nagappa, Somshekar; Shetty, Rohit; Shetty, Bhujang K

    2016-05-01

    To demonstrate the uses and applications of a microscope integrated intraoperative Optical Coherence Tomography in Micro Incision Cataract Surgery (MICS) and Femtosecond Laser Assisted Cataract Surgery (FLACS). Intraoperative real time imaging using the RESCAN™ 700 (Carl Zeiss Meditec, Oberkochen, Germany) was done for patients undergoing MICS as well as FLACS. The OCT videos were reviewed at each step of the procedure and the findings were noted and analyzed. Microscope Integrated Intraoperative Optical Coherence Tomography was found to be beneficial during all the critical steps of cataract surgery. We were able to qualitatively assess wound morphology in clear corneal incisions, in terms of subclinical Descemet's detachments, tears in the inner or outer wound lips, wound gaping at the end of surgery and in identifying the adequacy of stromal hydration, for both FLACS as well as MICS. It also enabled us to segregate true posterior polar cataracts from suspected cases intraoperatively. Deciding the adequate depth of trenching was made simpler with direct visualization. The final position of the intraocular lens in the capsular bag and the lack of bioadhesivity of hydrophobic acrylic lenses were also observed. Even though Microscope Integrated Intraoperative Optical Coherence Tomography is in its early stages for its application in cataract surgery, this initial assessment does show a very promising role for this technology in the future for cataract surgery both in intraoperative decision making as well as for training purposes.

  19. Image Tracking of Multiple C. Elegans Worms Using Adaptive Scanning Optical Microscope (ASOM)

    NASA Astrophysics Data System (ADS)

    Rivera, Linda; Potsaid, Benjamin; Wen, John T.

    2010-03-01

    Long-term imaging of living biological specimens is important to infer behaviorial trends and correlate neural structure with behavior. Such study is plagued by the field of view limitation in standard optical microscopes, as the motile specimen would frequently move out of view. A novel microscope, called the adaptive scanning optical microscope (ASOM), has recently been proposed to address this limitation. Through high speed post-objective scanning with a steering mirror, and compensation for optical aberrations with a MEMS deformable mirror, simultaneous imaging and tracking of multiple Caenorhabditis elegans worms has been demonstrated. This article presents the image processing algorithm for tracking multiple worms. Since the steering mirror has to move based on the predicted worm motion, image processing and stable steering mirror motion need to be executed at higher than the composite mosaic video frame rate (in contrast to existing works on image-based worm tracking, which are predominantly based on post-processing). Particular care is placed on disambiguating the worms when they overlap, collide, or entangle, where the worm tracking algorithm may fail. Results from both real time and simulated tracking are presented.

  20. Using a 1.2 GHz bandwidth reflective semiconductor optical amplifier with seeding light by 64-quadrature amplitude modulation orthogonal frequency division multiplexing modulation to achieve a 10-gbits/s upstream rate in long-reach passive optical network access

    NASA Astrophysics Data System (ADS)

    Yeh, Chien-Hung; Chen, Hsing-Yu; Chow, Chi-Wai; Wu, Yu-Fu

    2012-01-01

    We use a commercially available 1.2 GHz bandwidth reflective semiconductor optical amplifier (RSOA)--based optical network unit (ONU) to achieve 10-gbits/s upstream traffic for an optical orthogonal frequency division multiplexing (OFDM) long-reach passive optical network (LR-PON). This is the first time the 64--quadrature amplitude modulation (QAM) OFDM format has been applied to RSOA-ONU to achieve a 75 km fiber transmission length. In the proposed LR-PON, the upstream power penalty of 5.2 dB at the bit error rate of 3.8×10-3 is measured by using a 64-QAM OFDM modulation after the 75 km fiber transmission without dispersion compensation.

  1. Advanced Silicon Photonic Transceivers - the Case of a Wavelength Division and Polarization Multiplexed Quadrature Phase Shift Keying Receiver for Terabit/s Optical Transmission

    DTIC Science & Technology

    2017-03-10

    formats by the co- integration of a passive 90 degree optical hybrid, highspeed balanced Ge photodetectors and a high-speed two-channel transimpedance...40 Gbaud and can handle advanced modulation formats by the co-integration of a passive 90 degree optical hybrid, high- speed balanced Ge...polarization grating couplers, a 2 by 4 multi-mode interferometer (2x4-MMI) acting as a 90° hybrid, and 2 pair of balanced germanium photodiodes (Ge PDs

  2. A quantum gas microscope for detecting single atoms in a Hubbard-regime optical lattice.

    PubMed

    Bakr, Waseem S; Gillen, Jonathon I; Peng, Amy; Fölling, Simon; Greiner, Markus

    2009-11-05

    Recent years have seen tremendous progress in creating complex atomic many-body quantum systems. One approach is to use macroscopic, effectively thermodynamic ensembles of ultracold atoms to create quantum gases and strongly correlated states of matter, and to analyse the bulk properties of the ensemble. For example, bosonic and fermionic atoms in a Hubbard-regime optical lattice can be used for quantum simulations of solid-state models. The opposite approach is to build up microscopic quantum systems atom-by-atom, with complete control over all degrees of freedom. The atoms or ions act as qubits and allow the realization of quantum gates, with the goal of creating highly controllable quantum information systems. Until now, the macroscopic and microscopic strategies have been fairly disconnected. Here we present a quantum gas 'microscope' that bridges the two approaches, realizing a system in which atoms of a macroscopic ensemble are detected individually and a complete set of degrees of freedom for each of them is determined through preparation and measurement. By implementing a high-resolution optical imaging system, single atoms are detected with near-unity fidelity on individual sites of a Hubbard-regime optical lattice. The lattice itself is generated by projecting a holographic mask through the imaging system. It has an arbitrary geometry, chosen to support both strong tunnel coupling between lattice sites and strong on-site confinement. Our approach can be used to directly detect strongly correlated states of matter; in the context of condensed matter simulation, this corresponds to the detection of individual electrons in the simulated crystal. Also, the quantum gas microscope may enable addressing and read-out of large-scale quantum information systems based on ultracold atoms.

  3. Multifocal fluorescence microscope for fast optical recordings of neuronal action potentials.

    PubMed

    Shtrahman, Matthew; Aharoni, Daniel B; Hardy, Nicholas F; Buonomano, Dean V; Arisaka, Katsushi; Otis, Thomas S

    2015-02-03

    In recent years, optical sensors for tracking neural activity have been developed and offer great utility. However, developing microscopy techniques that have several kHz bandwidth necessary to reliably capture optically reported action potentials (APs) at multiple locations in parallel remains a significant challenge. To our knowledge, we describe a novel microscope optimized to measure spatially distributed optical signals with submillisecond and near diffraction-limit resolution. Our design uses a spatial light modulator to generate patterned illumination to simultaneously excite multiple user-defined targets. A galvanometer driven mirror in the emission path streaks the fluorescence emanating from each excitation point during the camera exposure, using unused camera pixels to capture time varying fluorescence at rates that are ∼1000 times faster than the camera's native frame rate. We demonstrate that this approach is capable of recording Ca(2+) transients resulting from APs in neurons labeled with the Ca(2+) sensor Oregon Green Bapta-1 (OGB-1), and can localize the timing of these events with millisecond resolution. Furthermore, optically reported APs can be detected with the voltage sensitive dye DiO-DPA in multiple locations within a neuron with a signal/noise ratio up to ∼40, resolving delays in arrival time along dendrites. Thus, the microscope provides a powerful tool for photometric measurements of dynamics requiring submillisecond sampling at multiple locations. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  4. Multifocal Fluorescence Microscope for Fast Optical Recordings of Neuronal Action Potentials

    PubMed Central

    Shtrahman, Matthew; Aharoni, Daniel B.; Hardy, Nicholas F.; Buonomano, Dean V.; Arisaka, Katsushi; Otis, Thomas S.

    2015-01-01

    In recent years, optical sensors for tracking neural activity have been developed and offer great utility. However, developing microscopy techniques that have several kHz bandwidth necessary to reliably capture optically reported action potentials (APs) at multiple locations in parallel remains a significant challenge. To our knowledge, we describe a novel microscope optimized to measure spatially distributed optical signals with submillisecond and near diffraction-limit resolution. Our design uses a spatial light modulator to generate patterned illumination to simultaneously excite multiple user-defined targets. A galvanometer driven mirror in the emission path streaks the fluorescence emanating from each excitation point during the camera exposure, using unused camera pixels to capture time varying fluorescence at rates that are ∼1000 times faster than the camera’s native frame rate. We demonstrate that this approach is capable of recording Ca2+ transients resulting from APs in neurons labeled with the Ca2+ sensor Oregon Green Bapta-1 (OGB-1), and can localize the timing of these events with millisecond resolution. Furthermore, optically reported APs can be detected with the voltage sensitive dye DiO-DPA in multiple locations within a neuron with a signal/noise ratio up to ∼40, resolving delays in arrival time along dendrites. Thus, the microscope provides a powerful tool for photometric measurements of dynamics requiring submillisecond sampling at multiple locations. PMID:25650920

  5. Intraoperative assessment of laryngeal pathologies with optical coherence tomography integrated into a surgical microscope.

    PubMed

    Englhard, Anna S; Betz, Tom; Volgger, Veronika; Lankenau, Eva; Ledderose, Georg J; Stepp, Herbert; Homann, Christian; Betz, Christian S

    2017-07-01

    Endoscopic examination followed by tissue biopsy is the gold standard in the evaluation of lesions of the upper aerodigestive tract. However, it can be difficult to distinguish between healthy mucosa, dysplasia, and invasive carcinoma. Optical coherence tomography (OCT) is a non-invasive technique which acquires high-resolution, cross-sectional images of tissue in vivo. Integrated into a surgical microscope, it allows the intraoperative evaluation of lesions simultaneously with microscopic visualization. In a prospective case series, we evaluated the use of OCT integrated into a surgical microscope during microlaryngoscopy to help differentiating various laryngeal pathologies. 33 patients with laryngeal pathologies were examined with an OCT- microscope (OPMedT iOCT-camera, HS Hi-R 1000G-microscope, Haag-Streit Surgical GmbH, Wedel, Germany) during microlaryngoscopy. The suspected intraoperative diagnoses were compared to the histopathological reports of subsequent tissue biopsies. Hands-free non-contact OCT revealed high-resolution images of the larynx with a varying penetration depth of up to 1.2 mm and an average of 0.6 mm. Picture quality was variable. OCT showed disorders of horizontal tissue layering in dysplasias with a disruption of the basement membrane in carcinomas. When comparing the suspected diagnosis during OCT-supported microlaryngoscopy with histology, 79% of the laryngeal lesions could be correctly identified. Premalignant lesions were difficult to diagnose and falsely classified as carcinoma. OCT integrated into a surgical microscope seems to be a promising adjunct tool to discriminate pathologies of the upper aerodigestive tract intraoperatively. However, picture quality and penetration depth were variable. Although premalignant lesions were difficult to diagnose, the system proved overall helpful for the intraoperative discrimination of benign and malignant tumors. Further studies will be necessary to define its value in the future. Lasers

  6. Assessing the Penetrating Abilities of Experimental Preparation with Dental Infiltrant Features Using Optical Microscope: Preliminary Study.

    PubMed

    Skucha-Nowak, Małgorzata; Machorowska-Pieniążek, Agnieszka; Tanasiewicz, Marta

    2016-01-01

    The aim of the infiltration technique is to penetrate demineralized enamel with a low viscosity resin. Icon® (DMG) is the first ever and so far the only dental infiltrant. Bacteriostaticity is one of the properties that should be inherent in dental infiltrants, but Icon lacks this feature. The aim of the preliminary study was to properly choose a dye which would allow us to assess the penetrating abilities of our own, experimental preparation with features of a dental infiltrant with bacteriostatic properties and to compare using an optical microscope the depth of infiltration of the designed experimental preparation with the infiltrant available on the market. The preparation is supposed to infiltrate decalcified human enamel and be assessed with an optical microscope. Eosin, neutral fuchsine and methylene blue were added to experimental preparation with dental infiltrant features and to Icon® (DMG) in order to assess the depth of penetration of the experimental solution into the decalcified layers of enamel. The experimental solution mixes well with eosin, neutral fuchsine, and methylene blue. During the preliminary study, the authors concluded that the experimental solution mixes well with methylene blue, neutral fuchsine, and eosin. An addition of eosin to a preparation which infiltrates inner, demineralized enamel layers, facilitates the assessment of such a preparation with an optical microscope. A designed experimental solution with the main ingredients, i.e., 2-hydroxyethyl methacrylate (HEMA) and tetraethylene glycol dimethacrylate (TEGDMA) with a ratio of 75% to 25% penetrates the demineralized (decalcified) inner parts of the enamel and polymerizes when exposed to light. In order to assess the infiltration of the experimental solution into the demineralized enamel layers, it is required to improve the measurement techniques that utilize optical microscopy.

  7. 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.

  8. Ultra-high resolution water window x ray microscope optics design and analysis

    NASA Technical Reports Server (NTRS)

    Shealy, David L.; Wang, C.

    1993-01-01

    This project has been focused on the design and analysis of an ultra-high resolution water window soft-x-ray microscope. These activities have been accomplished by completing two tasks contained in the statement of work of this contract. The new results from this work confirm: (1) that in order to achieve resolutions greater than three times the wavelength of the incident radiation, it will be necessary to use spherical mirror surfaces and to use graded multilayer coatings on the secondary in order to accommodate the large variations of the angle of incidence over the secondary when operating the microscope at numerical apertures of 0.35 or greater; (2) that surface contour errors will have a significant effect on the optical performance of the microscope and must be controlled to a peak-to-valley variation of 50-100 A and a frequency of 8 periods over the surface of a mirror; and (3) that tolerance analysis of the spherical Schwarzschild microscope has been shown that the water window operations will require 2-3 times tighter tolerances to achieve a similar performance of operations with 130 A radiation. These results have been included in a manuscript included in the appendix.

  9. Dual-mode optical microscope based on single-pixel imaging

    NASA Astrophysics Data System (ADS)

    Rodríguez, A. D.; Clemente, P.; Tajahuerce, E.; Lancis, J.

    2016-07-01

    We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no moving parts, works by sequential projection of a set of binary intensity patterns onto the sample that are codified onto a modified commercial DMD. Data to be displayed are geometrically transformed before written into a memory cell to cancel optical artifacts coming from the diamond-like shaped structure of the micromirror array. The 24-bit color depth of the display is fully exploited to increase the frame rate by a factor of 24, which makes the technique practicable for real samples. Our commercial DMD-based LED-illumination is cost effective and can be easily coupled as an add-on module for already existing inverted microscopes. The reflection and transmission information provided by our dual microscope complement each other and can be useful for imaging non-uniform samples and to prevent self-shadowing effects.

  10. Integrated source of broadband quadrature squeezed light.

    PubMed

    Hoff, Ulrich B; Nielsen, Bo M; Andersen, Ulrik L

    2015-05-04

    An integrated silicon nitride resonator is proposed as an ultra-compact source of bright single-mode quadrature squeezed light at 850 nm. Optical properties of the device are investigated and tailored through numerical simulations, with particular attention paid to loss associated with interfacing the device. An asymmetric double layer stack waveguide geometry with inverse vertical tapers is proposed for efficient and robust fibre-chip coupling, yielding a simulated total loss of -0.75 dB/facet. We assess the feasibility of the device through a full quantum noise analysis and derive the output squeezing spectrum for intra-cavity pump self-phase modulation. Subject to standard material loss and detection efficiencies, we find that the device holds promises for generating substantial quantum noise squeezing over a bandwidth exceeding 1 GHz. In the low-propagation loss regime, approximately -6 dB squeezing is predicted for a pump power of only 75 mW.

  11. Real-time structural integrity monitoring using a passive quadrature demodulated, localised Michelson optical fibre interferometer capable of simultaneous strain and acoustic emission sensing

    NASA Astrophysics Data System (ADS)

    Tapanes, Edward

    1991-12-01

    A Michelson Fiber optic sensor (MFOS) is described for in-situ strain and vibration monitoring as well as acoustic emission detection in composite material structures. The phase sensitive fiber optic sensor is localized, all-fiber, and intrinsic. The MFOS was successfully embedded in Kevlar/epoxy and graphite/epoxy thermosets as well as graphite/PEEK thermoplastic in order to perform local strain and vibration measurements at the lamina level. A technique allowing acoustic emission detection in parallel with strain and vibration monitoring is illustrated.

  12. The microscopic (optical and SEM) examination of putrefaction fluid deposits (PFD). Potential interest in forensic anthropology.

    PubMed

    Charlier, P; Georges, P; Bouchet, F; Huynh-Charlier, I; Carlier, R; Mazel, V; Richardin, P; Brun, L; Blondiaux, J; Lorin de la Grandmaison, G

    2008-10-01

    This article describes the potential interest in physical and forensic anthropology of the microscopic analysis of residues of putrefaction fluid, a calcified deposit frequently found associated with bone rests. Its sampling and analysis seem straightforward and relatively reproducible. Samples came from archeological material (Monterenzio Vecchia, an Etruscan necropolis from the north of Italy dated between the fifth and third century B.C.; body rests of Agnès Sorel, royal mistress died in 1450 A.D.; skull and grave of French King Louis the XI and Charlotte of Savoy dated from 1483 A.D.). All samples were studied by direct optical microscope and scanning electron microscopy. Many cytological, histological, and elemental analysis were possible, producing precious data for the identification of these remains and, in some cases, the cause of death.

  13. Giant vesicles (GV) in colloidal system under the optical polarization microscope (OPM).

    PubMed

    Khalid, Khalisanni; Noh, Muhammad Azri Mohd; Khan, M Niyaz; Ishak, Ruzaina; Penney, Esther; Chowdhury, Zaira Zaman; Hamzah, Mohammad Hafiz; Othman, Maizatulnisa

    2017-09-01

    This paper discusses the unprecedented microscopic findings of micellar growth in colloidal system (CS) of catalyzed piperidinolysis of ionized phenyl salicylate (PS(-)). The giant vesicles (GV) was observed under the optical polarization microscope (OPM) at [NaX]=0.1M where X=3-isopropC6H4O(-). The conditions were rationalized from pseudo-first-order rate constant, kobs of PS(-) of micellar phase at 31.1×10(-3)s(-1) reported in previous publication. The overall diameter of GV (57.6μm) in CS (CTABr/NaX/H2O)-catalyzed piperidinolysis (where X=3-isopropC6H4O) of ionized phenyl salicylate were found as giant unilamellar vesicles (GUV) and giant multilamellar vesicles (GMV). The findings were also validated by means of rheological analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. High-resolution full-field optical coherence tomography with a Linnik microscope.

    PubMed

    Dubois, Arnaud; Vabre, Laurent; Boccara, Alber-Claude; Beaurepaire, Emmanuel

    2002-02-01

    We describe an original microscope for high-resolution optical coherence tomography applications. Our system is based on a Linnik interference microscope with high-numerical-aperture objectives. Lock-in detection of the interference signal is achieved in parallel on a CCD by use of a photoelastic birefringence modulator and full-field stroboscopic illumination with an infrared LED. Transverse cross-section (en-face, or XY) images can be obtained in real time with better than 1-microm axial (Z) resolution and 0.5-microm transverse (XY) resolution. A sensitivity of approximately 80 dB is reached at a 1-image/s acquisition rate, which allows tomography in scattering media such as biological tissues.

  15. Microscope-integrated optical coherence tomography for image-aided positioning of glaucoma surgery

    NASA Astrophysics Data System (ADS)

    Li, Xiqi; Wei, Ling; Dong, Xuechuan; Huang, Ping; Zhang, Chun; He, Yi; Shi, Guohua; Zhang, Yudong

    2015-07-01

    Most glaucoma surgeries involve creating new aqueous outflow pathways with the use of a small surgical instrument. This article reported a microscope-integrated, real-time, high-speed, swept-source optical coherence tomography system (SS-OCT) with a 1310-nm light source for glaucoma surgery. A special mechanism was designed to produce an adjustable system suitable for use in surgery. A two-graphic processing unit architecture was used to speed up the data processing and real-time volumetric rendering. The position of the surgical instrument can be monitored and measured using the microscope and a grid-inserted image of the SS-OCT. Finally, experiments were simulated to assess the effectiveness of this integrated system. Experimental results show that this system is a suitable positioning tool for glaucoma surgery.

  16. Optical three-dimensional vibrometer microscope with picometer-resolution in x, y, and z

    NASA Astrophysics Data System (ADS)

    Rembe, Christian; Kowarsch, Robert; Ochs, Wanja; Dräbenstedt, Alexander; Giesen, Moritz; Winter, Marcus

    2014-03-01

    The state-of-the-art technique for optical vibration analysis of macroscopic structures is laser-Doppler vibrometry in which a single-laser beam measures the motion in the beam direction. Thus, three laser beams are necessary to investigate three-dimensional (3-D) motions. The laser spots can be separated on macroscopic specimens with scattering surfaces to prevent optical crosstalk between the measurement beams, but such separation is impossible for a microscopic scatter point. We demonstrate a solution for this problem: an optical 3-D vibrometer microscope with a single-impinging laser beam, which collects scattered light from at least three directions. We prove that it is possible to realize a small laser focus of <3.5-μm diameter on a proper scatter point such as an etch hole of a microelectromechanical-systems device to obtain real-time, 3-D vibration measurements with megahertz vibration bandwidth and picometer amplitude resolution. A first measurement of operational-deflection shapes is presented.

  17. Quantitative assessment of canalicular bile formation in isolated hepatocyte couplets using microscopic optical planimetry.

    PubMed Central

    Gautam, A; Ng, O C; Strazzabosco, M; Boyer, J L

    1989-01-01

    Isolated rat hepatocyte couplets (IRHC) are primary units of bile secretion that accumulate fluid in an enclosed canalicular space with time in culture. We have quantitated the rate of canalicular secretion in IRHC cultured for 4-8 h by measuring the change in canalicular space volume by video-microscopic optical planimetry using high resolution Nomarski optics. Electron microscopic morphometric studies revealed significant increases in canalicular membrane area after 4-6 h in culture. Canalicular secretion in basal L-15 medium (3.8 +/- 1.3 fl/min) increased significantly with the choleretic bile salts (10 microM), taurocholate, and ursodeoxycholate (14 +/- 7 fl/min each). Secretion rates after exposure to bile acids correlated directly with the canalicular surface area before stimulation. In contrast, expansion times after stimulation varied inversely with initial canalicular volumes. Ursodeoxycholic acid failed to produce a hypercholeresis at 10-, 100-, or 200-microM concentrations compared with taurocholate, either in normal or taurine-depleted IRHC. The present findings establish that rates of canalicular bile secretion can be quantitated in IRHC by serial optical planimetry, both in the basal state and after stimulation with bile acids. Furthermore, ursodeoxycholate does not acutely induce hypercholeresis at the canalicular level in this model. Rather, both taurocholic and ursodeoxycholic acids induced secretion in proportion to the surface area of the canalicular membrane. The IRHC are a useful model to identify canalicular choleretics and for studies of canalicular bile formation. Images PMID:2913052

  18. Real-time restoration of white-light confocal microscope optical sections

    PubMed Central

    Balasubramanian, Madhusudhanan; Iyengar, S. Sitharama; Beuerman, Roger W.; Reynaud, Juan; Wolenski, Peter

    2009-01-01

    Confocal microscopes (CM) are routinely used for building 3-D images of microscopic structures. Nonideal imaging conditions in a white-light CM introduce additive noise and blur. The optical section images need to be restored prior to quantitative analysis. We present an adaptive noise filtering technique using Karhunen–Loéve expansion (KLE) by the method of snapshots and a ringing metric to quantify the ringing artifacts introduced in the images restored at various iterations of iterative Lucy–Richardson deconvolution algorithm. The KLE provides a set of basis functions that comprise the optimal linear basis for an ensemble of empirical observations. We show that most of the noise in the scene can be removed by reconstructing the images using the KLE basis vector with the largest eigenvalue. The prefiltering scheme presented is faster and does not require prior knowledge about image noise. Optical sections processed using the KLE prefilter can be restored using a simple inverse restoration algorithm; thus, the methodology is suitable for real-time image restoration applications. The KLE image prefilter outperforms the temporal-average prefilter in restoring CM optical sections. The ringing metric developed uses simple binary morphological operations to quantify the ringing artifacts and confirms with the visual observation of ringing artifacts in the restored images. PMID:20186290

  19. Inspection of commercial optical devices for data storage using a three Gaussian beam microscope interferometer

    SciTech Connect

    Flores, J. Mauricio; Cywiak, Moises; Servin, Manuel; Juarez P, Lorenzo

    2008-09-20

    Recently, an interferometric profilometer based on the heterodyning of three Gaussian beams has been reported. This microscope interferometer, called a three Gaussian beam interferometer, has been used to profile high quality optical surfaces that exhibit constant reflectivity with high vertical resolution and lateral resolution near {lambda}. We report the use of this interferometer to measure the profiles of two commercially available optical surfaces for data storage, namely, the compact disk (CD-R) and the digital versatile disk (DVD-R). We include experimental results from a one-dimensional radial scan of these devices without data marks. The measurements are taken by placing the devices with the polycarbonate surface facing the probe beam of the interferometer. This microscope interferometer is unique when compared with other optical measuring instruments because it uses narrowband detection, filters out undesirable noisy signals, and because the amplitude of the output voltage signal is basically proportional to the local vertical height of the surface under test, thus detecting with high sensitivity. We show that the resulting profiles, measured with this interferometer across the polycarbonate layer, provide valuable information about the track profiles, making this interferometer a suitable tool for quality control of surface storage devices.

  20. Inspection of commercial optical devices for data storage using a three Gaussian beam microscope interferometer.

    PubMed

    Flores, J Mauricio; Cywiak, Moisés; Servín, Manuel; Juárez, Lorenzo

    2008-09-20

    Recently, an interferometric profilometer based on the heterodyning of three Gaussian beams has been reported. This microscope interferometer, called a three Gaussian beam interferometer, has been used to profile high quality optical surfaces that exhibit constant reflectivity with high vertical resolution and lateral resolution near lambda. We report the use of this interferometer to measure the profiles of two commercially available optical surfaces for data storage, namely, the compact disk (CD-R) and the digital versatile disk (DVD-R). We include experimental results from a one-dimensional radial scan of these devices without data marks. The measurements are taken by placing the devices with the polycarbonate surface facing the probe beam of the interferometer. This microscope interferometer is unique when compared with other optical measuring instruments because it uses narrowband detection, filters out undesirable noisy signals, and because the amplitude of the output voltage signal is basically proportional to the local vertical height of the surface under test, thus detecting with high sensitivity. We show that the resulting profiles, measured with this interferometer across the polycarbonate layer, provide valuable information about the track profiles, making this interferometer a suitable tool for quality control of surface storage devices.

  1. Fiber-optic laser-Doppler anemometer microscope applied to the cerebral microcirculation in rats.

    PubMed

    Seki, J; Sasaki, Y; Oyama, T; Yamamoto, J

    1996-01-01

    We have applied our developed fiber-optic laser-Doppler anemometer microscope (FLDAM) for the study of the cerebral microcirculation in the rat. The red cell velocity in single pial microvessels was successfully measured through a closed cranial window for the vessel diameter range from 7.8 to 230 microns. The temporal resolution of the FLDAM was sufficiently high to detect the pulsation in the arterioles. Arterio-venous distributions of the temporal mean red cell velocity and wall shear rate are also described.

  2. Full-field optical coherence tomography using immersion Mirau interference microscope.

    PubMed

    Lu, Sheng-Hua; Chang, Chia-Jung; Kao, Ching-Fen

    2013-06-20

    In this study, an immersion Mirau interference microscope was developed for full-field optical coherence tomography (FFOCT). Both the reference and measuring arms of the Mirau interferometer were filled with water to prevent the problems associated with imaging a sample in air with conventional FFOCT systems. The almost-common path interferometer makes the tomographic system less sensitive to environmental disturbances. En face OCT images at various depths were obtained with phase-shifting interferometry and Hariharan algorithm. This immersion interferometric method improves depth and quality in three-dimensional OCT imaging of scattering tissue.

  3. Electron microscopic and optical studies of prism faces of synthetic quartz

    NASA Technical Reports Server (NTRS)

    Buzek, B. C.; Vagh, A. S.

    1977-01-01

    Application of electron and optical microscopic techniques to the study of growth spirals on quartz crystal faces is described. Attention is centered on the centers of the spirals and on screw ledges; overhanging kinks are revealed on one side of the spiral centers. The possibility that these special features may have developed after growth of the crystals went to completion is explored. The conjecture is raised that such structures might result from adsorption of growth-inhibiting impurities at the center of the growth spiral on the quartz habit faces.

  4. Quasi-microscope concept for planetary missions. [optically augmented lander camera for high resolution microscopy

    NASA Technical Reports Server (NTRS)

    Huck, F. O.; Burcher, E. E.; Wall, S. D.; Arvidson, R. E.; Giat, O.

    1977-01-01

    Viking lander cameras have returned stereo and multispectral views of the Martian surface with a resolution that approaches 2 mm/lp in the near field. A two-orders-of-magnitude increase in resolution could be obtained for collected surface samples by augmenting these cameras with auxiliary optics that would neither impose special camera design requirements nor limit the cameras field of view of the terrain. Quasi-microscope images would provide valuable data on the physical and chemical characteristics of planetary regoliths.

  5. Enhanced microscopic nonlinear optical properties of novel Y-type chromophores with dual electron donor groups

    NASA Astrophysics Data System (ADS)

    Tang, Xiang; Pan, Lin; Jia, Kun; Tang, Xianzhong

    2016-03-01

    In this Letter, novel Y-type chromophores with dual electron donor groups, containing either styryl or azobenzene based π-conjugated bridge structures, were synthesized and their chemical structures, molecular configuration, microscopic optical properties as well as thermal properties were systematically characterized. The experimental results indicated that eight times increasing of second-order molecular hyperpolarizability as well as 50-100 nm blue shift of maximum absorption band for azobenzene based chromophore were observed by introducing Y-type dual electron donor groups, which was derived from the highly efficient 'total charge transfer' in this kind of chromophore as confirmed by the density functional theory calculation.

  6. Stable generation of quadrature entanglement using a ring interferometer

    SciTech Connect

    Eto, Yujiro; Nonaka, Akihiro; Hirano, Takuya; Zhang Yun

    2009-05-15

    We propose and demonstrate a scheme to stably generate quadrature-entangled optical pulses using a ring interferometer composed of an optical parametric amplifier and a dispersive media. The entangled light pulses at telecommunication wavelength are generated by combining two squeezed beams. In our scheme, the relative phase between the two beams is kept stable by the ring interferometer and is controllable using dispersive media. The amplitude and phase quadratures of the entangled beams are measured using two time-domain pulsed homodyne detectors. When the relative phase is fixed at {pi}/2, we verify the inseparability of the states by a sufficient criterion <{delta}{sup 2}[X{sub a}({phi}{sub 0})+X{sub b}({pi}-{phi}{sub 0})]>+<{delta}{sup 2}[X{sub a}({phi}{sub 0}{sup '})-X{sub b}(-{phi}{sub 0}{sup '})]>=0.64<1 where {phi}{sub 0}{sup '}-{phi}{sub 0}={pi}/2.

  7. A stereo-compound hybrid microscope for combined intracellular and optical recording of invertebrate neural network activity

    PubMed Central

    Frost, William N.; Wang, Jean; Brandon, Christopher J.

    2007-01-01

    Optical recording studies of invertebrate neural networks with voltage-sensitive dyes seldom employ conventional intracellular electrodes. This may in part be due to the traditional reliance on compound microscopes for such work. While such microscopes have high light-gathering power, they do not provide depth of field, making working with sharp electrodes difficult. Here we describe a hybrid microscope design, with switchable compound and stereo objectives, that eases the use of conventional intracellular electrodes in optical recording experiments. We use it, in combination with a voltage-sensitive dye and photodiode array, to identify neurons participating in the swim motor program of the marine mollusk Tritonia. This microscope design should be applicable to optical recording studies in many preparations. PMID:17306887

  8. Nonscanning three-dimensional optical microscope based on the reflectivity-height transformation for biological measurements.

    PubMed

    Chiu, Ming-Hung; Tan, Chen-Tai; Lee, Tsuan-Shih; Lee, Jain-Cheng

    2013-04-01

    We propose a nonscanning three-dimensional (3D) optical microscope based on reflectivity-height transformation in applications of biological and transparent plate measurements. The reflectivity of a prism can be transformed to the surface height of the specimen based on geometrical optics and the principle of internal reflection. Thus, the pattern of reflectivity is representative of the surface profile. Using charge-coupled device cameras to obtain the two-dimensional image patterns and combining with its reflectivity pattern, the 3D profile can be generated. The lateral resolution is determined by the diffraction limit, and the vertical resolution is better than several nanometers according to the incident angle and polarization used.

  9. Binary pseudorandom test standard to determine the modulation transfer function of optical microscopes

    SciTech Connect

    Novak, Erik; Trolinger, James D.; Lacey, Ian; Anderson, Erik H.; Artemiev, Nikolay A.; Babin, Sergey; Cabrini, Stefano; Calafiore, Guiseppe; Chan, Elaine R.; McKinney, Wayne R.; Peroz, Christophe; Takacs, Peter Z.; Yashchuk, Valeriy V.

    2015-09-01

    This work reports on the development of a binary pseudo-random test sample optimized to calibrate the MTF of optical microscopes. The sample consists of a number of 1-D and 2-D patterns, with different minimum sizes of spatial artifacts from 300 nm to 2 microns. We describe the mathematical background, fabrication process, data acquisition and analysis procedure to return spatial frequency based instrument calibration. We show that the developed samples satisfy the characteristics of a test standard: functionality, ease of specification and fabrication, reproducibility, and low sensitivity to manufacturing error. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  10. Microscopic Model of the Optical Absorption of Carbon Nanotubes Functionalized with Molecular Spiropyran Photoswitches

    NASA Astrophysics Data System (ADS)

    Malic, E.; Weber, C.; Richter, M.; Atalla, V.; Klamroth, T.; Saalfrank, P.; Reich, S.; Knorr, A.

    2011-03-01

    The adsorption of molecules to the surface of carbon nanostructures opens a new field of hybrid systems with distinct and controllable properties. We present a microscopic study of the optical absorption in carbon nanotubes functionalized with molecular spiropyran photoswitches. The switching process induces a change in the dipole moment leading to a significant coupling to the charge carriers in the nanotube. As a result, the absorption spectra of functionalized tubes reveal a considerable redshift of transition energies depending on the switching state of the spiropyran molecule. Our results suggest that carbon nanotubes are excellent substrates for the optical readout of spiropyran-based molecular switches. The gained insights can be applied to other noncovalently functionalized one-dimensional nanostructures in an externally induced dipole field.

  11. Microscopic optical model calculations of 4He, 12C-nucleus absorption cross sections

    NASA Technical Reports Server (NTRS)

    Dubey, R. R.; Khandelwal, G. S.; Cucinotta, F. A.; Wilson, J. W.

    1996-01-01

    Calculations of absorption cross sections using a microscopic first-order optical potential for heavy-ion scattering are compared with experiments. In-medium nucleon-nucleon (NN) cross sections were used to calculate the two-body scattering amplitude. A medium-modified first-order optical potential was obtained for heavy-ion scattering using the in-medium two-body scattering amplitude. A partial wave expansion of the Lippmann-Schwinger equation in momentum space was used to calculate the absorption cross sections for various systems. The results are presented for the absorption cross sections for 4He-nucleus and 12C-nucleus scattering systems and are compared with the experimental values in the energy range 18-83A MeV. The use of the in-medium NN cross sections is found to result in significant reduction of the free space absorption cross sections in agreement with experiment.

  12. Smart microscope: an adaptive optics learning system for aberration correction in multiphoton confocal microscopy.

    PubMed

    Albert, O; Sherman, L; Mourou, G; Norris, T B; Vdovin, G

    2000-01-01

    Off-axis aberrations in a beam-scanning multiphoton confocal microscope are corrected with a deformable mirror. The optimal mirror shape for each pixel is determined by a genetic learning algorithm, in which the second-harmonic or two-photon fluorescence signal from a reference sample is maximized. The speed of the convergence is improved by use of a Zernike polynomial basis for the deformable mirror shape. This adaptive optical correction scheme is implemented in an all-reflective system by use of extremely short (10-fs) optical pulses, and it is shown that the scanning area of an f:1 off-axis parabola can be increased by nine times with this technique.

  13. Optical lever calibration in atomic force microscope with a mechanical lever.

    PubMed

    Xie, Hui; Vitard, Julien; Haliyo, Sinan; Régnier, Stéphane

    2008-09-01

    A novel method that uses a small mechanical lever has been developed to directly calibrate the lateral sensitivity of the optical lever in the atomic force microscope (AFM). The mechanical lever can convert the translation into a nanoscale rotation angle with a flexible hinge that provides an accurate conversion between the photodiode voltage output and torsional angle of a cantilever. During the calibration, the cantilever is mounted on a holder attached on the lever, which brings the torsional axis of the cantilever and rotation axis of the lever into line. By making use of its nanomotion on the Z-axis and using an external motion on the barrier, this device can complete the local and full-range lateral sensitivity calibrations of the optical lever without modifying the actual AFM or the cantilevers.

  14. Macroscopic optical physiological parameters correlate with microscopic proliferation and vessel area breast cancer signatures.

    PubMed

    Chung, So Hyun; Feldman, Michael D; Martinez, Daniel; Kim, Helen; Putt, Mary E; Busch, David R; Tchou, Julia; Czerniecki, Brian J; Schnall, Mitchell D; Rosen, Mark A; DeMichele, Angela; Yodh, Arjun G; Choe, Regine

    2015-05-27

    Non-invasive diffuse optical tomography (DOT) and diffuse correlation spectroscopy (DCS) can detect and characterize breast cancer and predict tumor responses to neoadjuvant chemotherapy, even in patients with radiographically dense breasts. However, the relationship between measured optical parameters and pathological biomarker information needs to be further studied to connect information from optics to traditional clinical cancer biology. Thus we investigate how optically measured physiological parameters in malignant tumors such as oxy-, deoxy-hemoglobin concentration, tissue blood oxygenation, and metabolic rate of oxygen correlate with microscopic histopathological biomarkers from the same malignant tumors, e.g., Ki67 proliferation markers, CD34 stained vasculature markers and nuclear morphology. In this pilot study, we investigate correlations of macroscopic physiological parameters of malignant tumors measured by diffuse optical technologies with microscopic histopathological biomarkers of the same tumors, i.e., the Ki67 proliferation marker, the CD34 stained vascular properties marker, and nuclear morphology. The tumor-to-normal relative ratio of Ki67-positive nuclei is positively correlated with DOT-measured relative tissue blood oxygen saturation (R = 0.89, p-value: 0.001), and lower tumor-to-normal deoxy-hemoglobin concentration is associated with higher expression level of Ki67 nuclei (p-value: 0.01). In a subset of the Ki67-negative group (defined by the 15 % threshold), an inverse correlation between Ki67 expression level and mammary metabolic rate of oxygen was observed (R = -0.95, p-value: 0.014). Further, CD34 stained mean-vessel-area in tumor is positively correlated with tumor-to-normal total-hemoglobin and oxy-hemoglobin concentration. Finally, we find that cell nuclei tend to have more elongated shapes in less oxygenated DOT-measured environments. Collectively, the pilot data are consistent with the notion that increased blood is supplied to

  15. Squeezed quadrature fluctuations in a gravitational wave detector using squeezed light.

    PubMed

    Dwyer, S; Barsotti, L; Chua, S S Y; Evans, M; Factourovich, M; Gustafson, D; Isogai, T; Kawabe, K; Khalaidovski, A; Lam, P K; Landry, M; Mavalvala, N; McClelland, D E; Meadors, G D; Mow-Lowry, C M; Schnabel, R; Schofield, R M S; Smith-Lefebvre, N; Stefszky, M; Vorvick, C; Sigg, D

    2013-08-12

    Squeezed states of light are an important tool for optical measurements below the shot noise limit and for optical realizations of quantum information systems. Recently, squeezed vacuum states were deployed to enhance the shot noise limited performance of gravitational wave detectors. In most practical implementations of squeezing enhancement, relative fluctuations between the squeezed quadrature angle and the measured quadrature (sometimes called squeezing angle jitter or phase noise) are one limit to the noise reduction that can be achieved. We present calculations of several effects that lead to quadrature fluctuations, and use these estimates to account for the observed quadrature fluctuations in a LIGO gravitational wave detector. We discuss the implications of this work for quantum enhanced advanced detectors and even more sensitive third generation detectors.

  16. Quantitative posture analysis of 2D, 3D, and optical microscope visualization methods for microsurgery tasks.

    PubMed

    Yu, Denny; Sackllah, Michael; Woolley, Charles; Kasten, Steven; Armstrong, Thomas

    2012-01-01

    The purpose of this paper is to present a quantitative posture analysis of microsurgery tasks performed with different visualization methods. Microsurgery is traditionally performed using a binocular microscope; however surgeons are constrained by the optical eyepieces and are forced to assume joint angles that deviate away from neutral postures. This may be especially problematic for the neck and can increase surgeon discomfort and fatigue. Alternative visualization methods may improve surgeon posture by eliminating the constraints imposed by the microscope. This study examines both 2D and 3D heads-up displays as possible alternatives. Six subjects performed microsurgical tasks with each visualization methods for four hours. Quantitative posture analysis was done using Maxtraq software that tracks reflective markers on the subjects. The initial analysis of neck, upper arm, and elbow angles found significant differences between each display. A biomechanical analysis found that the differences in angles can result in loads on the neck joint that are twice as high in the microscope than the headsup displays. Although the alternative displays can result in better postures, improvements the display technology is needed to improve microsurgical task performance.

  17. 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.

  18. New computational solution to quantify synthetic material porosity from optical microscopic images.

    PubMed

    De Albuquerque, V H C; Filho, P P Rebouças; Cavalcante, T S; Tavares, J M R S

    2010-10-01

    This paper presents a new computational solution to quantify the porosity of synthetic materials from optical microscopic images. The solution is based on an artificial neuronal network of the multilayer perceptron type and a backpropagation algorithm is used for training. To evaluate this new solution, 40 sample images of a synthetic material were analysed and the quality of the results was confirmed by human visual analysis. In addition, these results were compared with ones obtained with a commonly used commercial system confirming their superior quality and the shorter time needed. The effect of images with noise was also studied and the new solution showed itself to be more reliable. The training phase of the new solution was analysed confirming that it can be performed in a very easy and straightforward manner. Thus, the new solution demonstrated that it is a valid and adequate option for researchers, engineers, specialists and other professionals to quantify the porosity of materials from microscopic images in an automatic, fast, efficient and reliable manner. © 2010 The Authors Journal compilation © 2010 The Royal Microscopical Society.

  19. Building 3D aerial image in photoresist with reconstructed mask image acquired with optical microscope

    NASA Astrophysics Data System (ADS)

    Chou, C. S.; Tang, Y. P.; Chu, F. S.; Huang, W. C.; Liu, R. G.; Gau, T. S.

    2012-03-01

    Calibration of mask images on wafer becomes more important as features shrink. Two major types of metrology have been commonly adopted. One is to measure the mask image with scanning electron microscope (SEM) to obtain the contours on mask and then simulate the wafer image with optical simulator. The other is to use an optical imaging tool Aerial Image Measurement System (AIMSTM) to emulate the image on wafer. However, the SEM method is indirect. It just gathers planar contours on a mask with no consideration of optical characteristics such as 3D topography structures. Hence, the image on wafer is not predicted precisely. Though the AIMSTM method can be used to directly measure the intensity at the near field of a mask but the image measured this way is not quite the same as that on the wafer due to reflections and refractions in the films on wafer. Here, a new approach is proposed to emulate the image on wafer more precisely. The behavior of plane waves with different oblique angles is well known inside and between planar film stacks. In an optical microscope imaging system, plane waves can be extracted from the pupil plane with a coherent point source of illumination. Once plane waves with a specific coherent illumination are analyzed, the partially coherent component of waves could be reconstructed with a proper transfer function, which includes lens aberration, polarization, reflection and refraction in films. It is a new method that we can transfer near light field of a mask into an image on wafer without the disadvantages of indirect SEM measurement such as neglecting effects of mask topography, reflections and refractions in the wafer film stacks. Furthermore, with this precise latent image, a separated resist model also becomes more achievable.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  2. Three-dimensional phase-contrast X-ray microtomography with scanning-imaging X-ray microscope optics.

    PubMed

    Takeuchi, Akihisa; Uesugi, Kentaro; Suzuki, Yoshio

    2013-09-01

    A three-dimensional (3D) X-ray tomographic micro-imaging system has been developed. The optical system is based on a scanning-imaging X-ray microscope (SIXM) optics, which is a hybrid system consisting of a scanning microscope optics with a one-dimensional (1D) focusing (line-focusing) device and an imaging microscope optics with a 1D objective. In the SIXM system, each 1D dataset of a two-dimensional (2D) image is recorded independently. An object is illuminated with a line-focused beam. Positional information of the region illuminated by the line-focused beam is recorded with the 1D imaging microscope optics as line-profile data. By scanning the object with the line focus, 2D image data are obtained. In the same manner as for a scanning microscope optics with a multi-pixel detector, imaging modes such as phase contrast and absorption contrast can be arbitrarily configured after the image data acquisition. By combining a tomographic scan method and the SIXM system, quantitative 3D imaging is performed. Results of a feasibility study of the SIXM for 3D imaging are shown.

  3. Holographic microscope for measuring displacements of vibrating microbeams using time-averaged, electro-optic holography

    NASA Astrophysics Data System (ADS)

    Brown, Gordon C.; Pryputniewicz, Ryszard J.

    1998-05-01

    An optical microscope, utilizing the principles of time- averaged hologram interferometry, is described for microelectromechanical systems (MEMS) applications. MEMS are devices fabricated via techniques such as microphotolithography to create miniature actuators and sensors. Many of these sensors are currently deployed in automotive applications which rely on, or depend on, the dynamic behavior of the sensor, e.g., airbag sensors, ride monitoring suspensions sensors, etc. Typical dimensions of current MEMS devices are measured in micrometers, a small fraction of the diameter of a human hair, and the current trends is to further decrease the size of MEMS devices to submicrometer dimensions. However, the smaller MEMS become, the more challenging it is to measure with accuracy the dynamic characteristics of these devices. An electro-optic holographic microscope (EOHM) for the purpose of studying the dynamic behavior of MEMS type devices is described. Additionally, by performing phase measurements within an EOHM image, object displacements are determined as illustrated by representative examples. With the EOHM, devices with surface sizes ranging from approximately 35 X 400 to 5 X 18 micrometers are studied while undergoing resonant vibrations at frequencies as high as 2 MHz.

  4. A Microscopic Optical Potential Approach to {sup 6,8}He+p Elastic Scattering

    SciTech Connect

    Lukyanov, V. K.; Zemlyanaya, E. V.; Lukyanov, K. V.; Kadrev, D. N.; Antonov, A. N.; Gaidarov, M. K.; Massen, S. E.

    2009-08-26

    A microscopic approach to calculate the optical potential (OP) with the real part obtained by a folding procedure and with the imaginary part inherent in the high-energy approximation (HEA) is applied to study the {sup 6,8}He+p elastic scattering data at energies of tens of MeV/N. The OP's and the cross sections are calculated using different models for the neutron and proton densities of {sup 6,8}He. The role of the spin-orbit (SO) potential and effects of the energy and density dependence of the effective NN forces are studied. Comparison of the calculations with the available experimental data on the elastic scattering differential cross sections at beam energies <100 MeV/N is performed and conclusions on the role of the aforesaid effects are made. It is shown that the present approach, which uses only parameters that renormalize the depths of the OP, can be applied along with other methods like that from the microscopic g-matrix description of the complex proton optical potential.

  5. A single-pixel optical-sectioning programmable array microscope (SP-PAM)

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Ye, P.; Arce, G. R.; Prather, D. W.

    2010-02-01

    Programmable array microscopes (PAMs) use "multi-pinhole" masks in confocal image planes to introduce illumination and block the "out-of-focus light". Compared to traditional confocal microscopes (CM), PAM systems have higher efficiency in utilizing the signal light and faster image acquisition speed. However, these advantages are gained at the cost of using more complicated optics and detectors. Compressive sampling (CS) measurement patterns can be used as pinhole masks in PAM systems. With CS patterns, the light collected after the detector mask can be summed up and used to reconstruct the imaging scene via solving an l1-minimization problem. Only a simple relay-lens and a singlepixel detector are needed to measure the intensity of the summed light. Therefore the optical complexity associated with conventional PAM systems can be reduced. Since only a single-pixel detector is needed, this system can also be called a single-pixel PAM or SP-PAM system. In this work, we introduce the design and fabrication of a prototype SP-PAM system. In this system, scrambled-block Hadamard ensembles (SBHE) are used as CS measurement patterns and a digital micromirror device (DMD) is employed to realize these patterns.

  6. X-ray excited optical luminescence detection by scanning near-field optical microscope: a new tool for nanoscience.

    PubMed

    Larcheri, Silvia; Rocca, Francesco; Jandard, Frank; Pailharey, Daniel; Graziola, Roberto; Kuzmin, Alexei; Purans, Juris

    2008-01-01

    Investigations of complex nanostructured materials used in modern technologies require special experimental techniques able to provide information on the structure and electronic properties of materials with a spatial resolution down to the nanometer scale. We tried to address these needs through the combination of x-ray absorption spectroscopy (XAS) using synchrotron radiation microbeams with scanning near-field optical microscopy (SNOM) detection of the x-ray excited optical luminescence (XEOL) signal. This new instrumentation offers the possibility to carry out a selective structural analysis of the sample surface with the subwavelength spatial resolution determined by the SNOM probe aperture. In addition, the apex of the optical fiber plays the role of a topographic probe, and chemical and topographic mappings can be simultaneously recorded. Our working XAS-SNOM prototype is based on a quartz tuning-fork head mounted on a high stability nanopositioning system; a coated optical fiber tip, operating as a probe in shear-force mode; a detection system coupled with the microscope head control system; and a dedicated software/hardware setup for synchronization of the XEOL signal detection with the synchrotron beamline acquisition system. We illustrate the possibility to obtain an element-specific contrast and to perform nano-XAS experiments by detecting the Zn K and W L(3) absorption edges in luminescent ZnO and mixed ZnWO(4)-ZnO nanostructured thin films.

  7. Optical microscope using an interferometric source of two-color, two-beam entangled photons

    DOEpatents

    Dress, William B.; Kisner, Roger A.; Richards, Roger K.

    2004-07-13

    Systems and methods are described for an optical microscope using an interferometric source of multi-color, multi-beam entangled photons. A method includes: downconverting a beam of coherent energy to provide a beam of multi-color entangled photons; converging two spatially resolved portions of the beam of multi-color entangled photons into a converged multi-color entangled photon beam; transforming at least a portion of the converged multi-color entangled photon beam by interaction with a sample to generate an entangled photon specimen beam; and combining the entangled photon specimen beam with an entangled photon reference beam within a single beamsplitter. An apparatus includes: a multi-refringent device providing a beam of multi-color entangled photons; a condenser device optically coupled to the multi-refringent device, the condenser device converging two spatially resolved portions of the beam of multi-color entangled photons into a converged multi-color entangled photon beam; a beam probe director and specimen assembly optically coupled to the condenser device; and a beam splitter optically coupled to the beam probe director and specimen assembly, the beam splitter combining an entangled photon specimen beam from the beam probe director and specimen assembly with an entangled photon reference beam.

  8. Aggressive orbital optic nerve meningioma with benign microscopic features: a case report.

    PubMed

    Amoli, F Asadi; Mehrabani, P Mansouri; Tari, A Sadeghi

    2007-12-01

    Primary optic nerve meningiomas occur at lower ages than meningiomas arising from the coverings of the brain and spinal cord. Here we report the case of a 20-year-old female with an aggressive orbital meningioma referred to the Ophthalmology Department of the Farabi Hospital in Tehran. The patient had a history of orbital meningioma from 10 years ago and several surgical resections due to tumor recurrence during these 10 years. On admission, the patient had a large orbital mass and severe proptosis. MRI images revealed a large left orbital mass with optic nerve involvement and extension to the left maxillary sinus, pterygoid fossa and the dura in the floor of the anterior fossa. Fine-needle aspiration cytology of the mass confirmed tumor recurrence. The patient first received radiotherapy due to the inoperable mass, and the tumor was resected 1.5 month later. Microscopic study showed meningotheliomatous meningioma with extensive involvement of the optic nerve and invasion of the optic disc, sclera and choroid. The interesting aspect of this case was the aggressive behavior of the tumor with intraocular invasion, despite its benign histopathological features, which led to wide exenteration of the eye together with resection of the upper and lower lids.

  9. Novel failure analysis techniques using photon probing with a scanning optical microscope

    SciTech Connect

    Cole, E.I. Jr.; Soden, J.M.; Rife, J.L.; Barton, D.L.; Henderson, C.L.

    1993-12-31

    Three new failure analysis techniques for integrated circuits (ICs) have been developed using localized photon probing with a scanning optical microscope (SOM). The first two are light-induced voltage alteration (LIVA) imaging techniques that (1) localize open-circuited and damaged junctions and (2) image transistor logic states. The third technique uses the SOM to control logic states optically from the IC backside. LIVA images are produced by monitoring the voltage fluctuations of a constant current power supply as a laser beam is scanned over the IC. High selectivity for localizing defects has been demonstrated using the LIVA approach. Logic state mapping results, similar to previous work using biased optical beam induced current (OBIC) and laser probing approaches have also been produced using LIVA. Application of the two LIVA based techniques to backside failure analysis has been demonstrated using an infrared laser source. Optical logic state control is based upon earlier work examining transistor response to photon injection. The physics of each method and their applications for failure analysis are described.

  10. Quantum coherent optical phase modulation in an ultrafast transmission electron microscope.

    PubMed

    Feist, Armin; Echternkamp, Katharina E; Schauss, Jakob; Yalunin, Sergey V; Schäfer, Sascha; Ropers, Claus

    2015-05-14

    Coherent manipulation of quantum systems with light is expected to be a cornerstone of future information and communication technology, including quantum computation and cryptography. The transfer of an optical phase onto a quantum wavefunction is a defining aspect of coherent interactions and forms the basis of quantum state preparation, synchronization and metrology. Light-phase-modulated electron states near atoms and molecules are essential for the techniques of attosecond science, including the generation of extreme-ultraviolet pulses and orbital tomography. In contrast, the quantum-coherent phase-modulation of energetic free-electron beams has not been demonstrated, although it promises direct access to ultrafast imaging and spectroscopy with tailored electron pulses on the attosecond scale. Here we demonstrate the coherent quantum state manipulation of free-electron populations in an electron microscope beam. We employ the interaction of ultrashort electron pulses with optical near-fields to induce Rabi oscillations in the populations of electron momentum states, observed as a function of the optical driving field. Excellent agreement with the scaling of an equal-Rabi multilevel quantum ladder is obtained, representing the observation of a light-driven 'quantum walk' coherently reshaping electron density in momentum space. We note that, after the interaction, the optically generated superposition of momentum states evolves into a train of attosecond electron pulses. Our results reveal the potential of quantum control for the precision structuring of electron densities, with possible applications ranging from ultrafast electron spectroscopy and microscopy to accelerator science and free-electron lasers.

  11. Quantum coherent optical phase modulation in an ultrafast transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Feist, Armin; Echternkamp, Katharina E.; Schauss, Jakob; Yalunin, Sergey V.; Schäfer, Sascha; Ropers, Claus

    2015-05-01

    Coherent manipulation of quantum systems with light is expected to be a cornerstone of future information and communication technology, including quantum computation and cryptography. The transfer of an optical phase onto a quantum wavefunction is a defining aspect of coherent interactions and forms the basis of quantum state preparation, synchronization and metrology. Light-phase-modulated electron states near atoms and molecules are essential for the techniques of attosecond science, including the generation of extreme-ultraviolet pulses and orbital tomography. In contrast, the quantum-coherent phase-modulation of energetic free-electron beams has not been demonstrated, although it promises direct access to ultrafast imaging and spectroscopy with tailored electron pulses on the attosecond scale. Here we demonstrate the coherent quantum state manipulation of free-electron populations in an electron microscope beam. We employ the interaction of ultrashort electron pulses with optical near-fields to induce Rabi oscillations in the populations of electron momentum states, observed as a function of the optical driving field. Excellent agreement with the scaling of an equal-Rabi multilevel quantum ladder is obtained, representing the observation of a light-driven `quantum walk' coherently reshaping electron density in momentum space. We note that, after the interaction, the optically generated superposition of momentum states evolves into a train of attosecond electron pulses. Our results reveal the potential of quantum control for the precision structuring of electron densities, with possible applications ranging from ultrafast electron spectroscopy and microscopy to accelerator science and free-electron lasers.

  12. An Alternative Tapping Scanning Near-Field Optical Microscope Setup Enabling the Study of Biological Systems in Liquid Environment

    NASA Astrophysics Data System (ADS)

    Girasole, M.; Longo, G.; Cricenti, A.

    2006-03-01

    A new aperture scanning near-field optical microscope operating in the intermittent contact mode using a non-bent optical fiber is introduced. The microscope was built modifying a classical scanning near-field optical microscope (SNOM) unit introducing a patented probe-holder (MTP) which contains a piezo-motor and a bimorph-transductor. The main advantages of the present set-up in terms of stability, versatility, optical resolution, and quality of the collected signals are described. The instrument works properly while exerting a minimum perturbation on the sample thus overcoming the major drawbacks of different SNOM-based imaging modes and allowing to study very delicate samples including living cells in physiological environment.

  13. Error correction based on micro-scanning preprocessing for an optical micro-scanning thermal microscope imaging system

    NASA Astrophysics Data System (ADS)

    Gao, Meijing; Xu, Jie; Tan, Ailing; Zu, Zhenlong; Yang, Ming; Wang, Jingyuan

    2017-06-01

    In recent years, various thermal microscope imaging systems have been developed to meet the demands of micro-thermal analysis for large-scale integrated circuits, biomedical, science, and research fields. However, conventional thermal microscope imaging systems, which use cooled infrared detectors are heavy and expensive. In order to solve this problem, we developed a thermal microscope imaging system based on an uncooled infrared detector. However, the spatial resolution of the thermal microscope imaging system based on an uncooled infrared detector is low. With optical micro-scanning technology, the spatial resolution of the thermal microscope imaging system can be increased without increasing the detector dimension or reducing the detector unit size. In order to improve its spatial resolution, a micro-scanning system based on optical plate rotation was developed, and an optical microscanning thermal microscope imaging system was obtained after the integrated design. Due to environmental factors, mechanical vibration, alignment error and other factors, there is micro-scanning error in the designed micro-scanning thermal microscope imaging system. The four low-resolution images collected by micro-scanning thermal microscope imaging system are not standard down-sampled images. The quality of the image interpolated directly by four collected images is reduced and the performance of the micro-scanning system isn't fully exploited. Therefore, based on the proposed second-order oversampling reconstruction micro-scanning error correction algorithm and the new edge directed interpolation algorithm, a new micro-scanning error correction technique is proposed. Simulations and experiments show that the proposed technique can effectively reduce optical micro-scanning error, improve the systems spatial resolution and optimize the effect of the imaging system. It can be applied to other electro-optical imaging systems to improve their spatial resolution.

  14. Application of evanescent wave optics to the determination of absolute distance in surface force measurements using the atomic force microscope.

    PubMed

    Huntington, S T; Hartley, P G; Katsifolis, J

    2003-04-01

    A combined scanning near field optical/atomic force microscope (AFM) is used to obtain surface force measurements between a near field sensing tip and a tapered optical fibre surface, whilst simultaneously detecting the intensity of the evanescent field emanating from the fibre. The tapered optical fibre acts as a compliant sample to demonstrate the possible use of the near field intensity measurement system in determining 'real' surface separations from normal AFM surface force measurements at sub-nanometer resolution between deformable surfaces.

  15. An optical sectioning programmable array microscope implemented with a digital micromirror device.

    PubMed

    Hanley, Q S; Verveer, P J; Gemkow, M J; Arndt-Jovin, D; Jovin, T M

    1999-12-01

    The defining feature of a programmable array microscope (PAM) is the presence of a spatial light modulator in the image plane. A spatial light modulator used singly or as a matched pair for both illumination and detection can be used to generate an optical section. Under most conditions, the basic optical properties of an optically sectioning PAM are similar to those of rotating Nipkow discs. The method of pattern generation, however, is fundamentally different and allows arbitrary illumination patterns to be generated under programmable control, and sectioning strategies to be changed rapidly in response to specific experimental conditions. We report the features of a PAM incorporating a digital micromirror device, including the axial sectioning response to fluorescent thin films and the imaging of biological specimens. Three axial sectioning strategies were compared: line scans, dot lattice scans and pseudo-random sequence scans. The three strategies varied widely in light throughput, sectioning strength and robustness when used on real biological samples. The axial response to thin fluorescent films demonstrated a consistent decrease in the full width at half maximum (FWHM), accompanied by an increase in offset, as the unit cells defining the patterns grew smaller. Experimental axial response curves represent the sum of the response from a given point of illumination and cross-talk from neighbouring points. Cross-talk is minimized in the plane of best focus and when measured together with the single point response produces a decrease in FWHM. In patterns having constant throughput, there appears to be tradeoff between the FWHM and the size of the offset. The PAM was compared to a confocal laser scanning microscope using biological samples. The PAM demonstrated higher signal levels and dynamic range despite a shorter acquisition time. It also revealed more structures in x-z sections and less intensity drop-off with scanning depth.

  16. Automatic quadrature control and measuring system

    NASA Technical Reports Server (NTRS)

    Hamlet, J. F.

    1973-01-01

    Quadrature is separated from amplified signal by use of phase detector, with phase shifter providing appropriate reference. Output of phase detector is further amplified and filtered by dc amplifier. Output of dc amplifier provides signal to neutralize quadrature component of transducer signal.

  17. IC quadrature filters for analog multipliers

    NASA Astrophysics Data System (ADS)

    Tarasov, V. P.; Timonteev, V. N.

    1980-08-01

    The paper considers the design of symmetric and asymmetric quadrature filters. Formulas are presented for transfer functions, nonlinear distortions, q-factor, and dynamic range for different filter connections in the direct-transmission channels. The integrated design of a highpass quadrature filter is considered.

  18. Error Analysis of Quadrature Rules. Classroom Notes

    ERIC Educational Resources Information Center

    Glaister, P.

    2004-01-01

    Approaches to the determination of the error in numerical quadrature rules are discussed and compared. This article considers the problem of the determination of errors in numerical quadrature rules, taking Simpson's rule as the principal example. It suggests an approach based on truncation error analysis of numerical schemes for differential…

  19. Error Analysis of Quadrature Rules. Classroom Notes

    ERIC Educational Resources Information Center

    Glaister, P.

    2004-01-01

    Approaches to the determination of the error in numerical quadrature rules are discussed and compared. This article considers the problem of the determination of errors in numerical quadrature rules, taking Simpson's rule as the principal example. It suggests an approach based on truncation error analysis of numerical schemes for differential…

  20. Sedimentological Investigations of the Martian Surface using the Mars 2001 Robotic Arm Camera and MECA Optical Microscope

    NASA Technical Reports Server (NTRS)

    Rice, J. W., Jr.; Smith, P. H.; Marshall, J. R.

    1999-01-01

    The first microscopic sedimentological studies of the Martian surface will commence with the landing of the Mars Polar Lander (MPL) December 3, 1999. The Robotic Arm Camera (RAC) has a resolution of 25 um/p which will permit detailed micromorphological analysis of surface and subsurface materials. The Robotic Ann will be able to dig up to 50 cm below the surface. The walls of the trench will also be inspected by RAC to look for evidence of stratigraphic and / or sedimentological relationships. The 2001 Mars Lander will build upon and expand the sedimentological research begun by the RAC on MPL. This will be accomplished by: (1) Macroscopic (dm to cm): Descent Imager, Pancam, RAC; (2) Microscopic (mm to um RAC, MECA Optical Microscope (Figure 2), AFM This paper will focus on investigations that can be conducted by the RAC and MECA Optical Microscope.

  1. Unveiling nanometric plasmons optical properties with advanced electron spectroscopy in the Scanning Transmission Electron Microscope

    NASA Astrophysics Data System (ADS)

    Kociak, Mathieu

    Since the pioneering work of Yamamoto, the use of electron spectroscopy such as Cathodoluminescence (CL) and Electron Energy Loss Spectroscopy (EELS) in a Scanning (Transmission) Electron Microscope (STEM) has considerably helped improving our understanding of the optical properties of metallic nanoparticles. The resemblance of spectroscopic signals from electron and pure optical techniques leads to the intuition that both types of techniques are very close, an idea theoretically discussed by F.J. Garcia de Abajo and coworkers. However, it is also quite intuitive that CL and EELS should be different. For example, EELS helps detecting any sort of modes while CL can only detect radiative ones. On the other hand, even between optical spectroscopy techniques, clear differences such as energy shifts or spectral shapes changes are expected in the case of plasmons. The lack of adapted instrumentation capable of performing combined EELS and CL, as well as theoretical developments allowing to account for the generic difference between EELS and CL and their optical counterparts impeached a comprehensive understanding of plasmons physics with the otherwise amazing electron spectroscopies. In this talk, I will present recent experimental results showing combined EELS and CL spectral mapping of plasmonic properties for nanoparticles with several shapes (triangles, cubes, stars...) and composition (gold, silver, aluminum...). Helped with different theoretical tools, I will try to show how these results can be related to their optical counterparts (extinction, scattering), and what type of physical insights can be gained from these combined measurements. Finally, if time allows, pointing the weaknesses of state-of-the-art CL and EELS (in terms of spectral range and/or spectral resolution), I will present EELS results obtained on highly monochromated electron beams that could cope with these limitations

  2. Macrophage with gold nanorod visualized by optical-resolution and acoustic-resolution photoacoustic microscopes.

    PubMed

    Yamazaki, Rena; Ogasawara, Koetsu; Fujiwara, Mitsuhiro; Kobayashi, Kazuto; Saijo, Yoshifumi

    2015-01-01

    Macrophages play a key role in inflammation and they are frequently observed in vulnerable atherosclerotic plaque. In the present study, macrophages phagocytosing gold nanorod (AuNR) were observed by optical-resolution (OR) and acoustic-resolution (AR) photoacoustic microscope (PAM). The OR-PAM consisted of diode laser optically focused to 60 micron and planar ultrasonic transducer with the central frequency of 8 MHz placed under the object. AR-PAM consisted of concave ultrasonic transducer with the central frequency of 20 MHz and optical fiber through the center hole of the transducer for laser irradiation. First, PA signal from gold, silver and copper wire were measured in order to determine the best metal substrate for enhancing PA contrast. Gold generated largest PA signal. AuNR with the resonance wavelength of 1064 nm was co-cultured with the macrophages for phagocytosis. PA signal was successfully detected from macrophages with AuNR by both OR-PAM and AR-PAM. PA imaging of the macrophages with AuNR indicates inflammation in the vulnerable plaque and AR-PAM method would be applicable for clinical settings.

  3. Microscopic scattering imaging measurement and digital evaluation system of defects for fine optical surface

    NASA Astrophysics Data System (ADS)

    Liu, Dong; Yang, Yongying; Wang, Lin; Zhuo, Yongmo; Lu, Chunhua; Yang, Liming; Li, Ruijie

    2007-10-01

    According to ISO10110-7 and the engineering standards of Inertial Confinement Fusion (ICF), this paper presents a microscopic scattering imaging and analyzing system which allows one to automatically evaluate defects in random distributions and shapes on the surface of fine optical components of large aperture. The annularly disposed multi-beam fiber light sources illuminate the target surface with a special angle. The image, which has bright defects on black background, is suitable for digital image processing. With XY-scanning system, the defect information of full aperture can be obtained by stitching the sub-aperture image array, according to the algorithms of template matching. The full aperture image is divided into N × N sub-apertures, each of which has view field of approximate 3 mm × 4 mm. Image processing software for image recognition has been established using mathematical morphology with high computing efficiency and friendly graphics user interface. A group of standard reticules fabricated by binary optics can scale defects for calibration. As a result the lateral resolution of the system is better than sub-micrometer while the total view field can be hundreds of millimeters. The comparison quantitative data results between the experiment and standard demonstrate the system is competent for the digital evaluation of defect characterization of fine optical surfaces, especially for the ones with large aperture.

  4. High-frequency H-PDLC optical chopper for frequency division multiplexing fluorescence confocal microscope system

    NASA Astrophysics Data System (ADS)

    Jiang, Yanmeng; Zheng, Jihong; Tang, Pingyu; Wang, Tingting; Huang, Aiqin; Zhou, Zengjun; Zhuang, Songlin

    2011-10-01

    The optical chopper array based on Holographic Polymer Dispersed Liquid Crystal (H-PDLC) working at high frequencies, for example 1KHz, 2KHz, and its application in an improved Frequency Division Multiplexed Fluorescence Confocal Microscope (FDMFCM) system are reported in this article. The system is a combination of the confocal microscopy and the frequency division multiplexing technique. Taking advantages of the optical chopper array based on H-PDLC that avoids mechanical movements, the FDMFCM system is able to obtain better Signal-Noise Ratio (SNR), smaller volume, more independent channels and more efficient scanning. What's more, the FDMCFM maintained the high special resolution ability and realized faster temporal resolution than pervious system. Using the proposed device, the FDMFCM system conducts successful parallel detection of rat neural cells. Fluorescence intensity signals from two different points on the specimen, which represent concentration of certain kind of proteins in the sample cells, are achieved. The experimental results show that the proposed H-PDLC optical chopper array has feasibility in FDMFCM system, which owes to its unique characteristics such as fast response, simple fabrication and lower consumption etc. With the development of H-PDLC based devices, there will be prospective in upgrading FDMFCM system's performance in the biomedical area.

  5. A Multiscale Material Testing System for In Situ Optical and Electron Microscopes and Its Application

    PubMed Central

    Ye, Xuan; Cui, Zhiguo; Fang, Huajun; Li, Xide

    2017-01-01

    We report a novel material testing system (MTS) that uses hierarchical designs for in-situ mechanical characterization of multiscale materials. This MTS is adaptable for use in optical microscopes (OMs) and scanning electron microscopes (SEMs). The system consists of a microscale material testing module (m-MTM) and a nanoscale material testing module (n-MTM). The MTS can measure mechanical properties of materials with characteristic lengths ranging from millimeters to tens of nanometers, while load capacity can vary from several hundred micronewtons to several nanonewtons. The m-MTM is integrated using piezoelectric motors and piezoelectric stacks/tubes to form coarse and fine testing modules, with specimen length from millimeters to several micrometers, and displacement distances of 12 mm with 0.2 µm resolution for coarse level and 8 µm with 1 nm resolution for fine level. The n-MTM is fabricated using microelectromechanical system technology to form active and passive components and realizes material testing for specimen lengths ranging from several hundred micrometers to tens of nanometers. The system’s capabilities are demonstrated by in-situ OM and SEM testing of the system’s performance and mechanical properties measurements of carbon fibers and metallic microwires. In-situ multiscale deformation tests of Bacillus subtilis filaments are also presented. PMID:28777341

  6. Adaptive optics–optical coherence tomography: optimizing visualization of microscopic retinal structures in three dimensions

    PubMed Central

    Zawadzki, Robert J.; Choi, Stacey S.; Jones, Steven M.; Oliver, Scot S.; Werner, John S.

    2008-01-01

    Adaptive optics–optical coherence tomography (AO-OCT) permits improved imaging of microscopic retinal structures by combining the high lateral resolution of AO with the high axial resolution of OCT, resulting in the narrowest three-dimensional (3D) point-spread function (PSF) of all in vivo retinal imaging techniques. Owing to the high volumetric resolution of AO-OCT systems, it is now possible, for the first time, to acquire images of 3D cellular structures in the living retina. Thus, with AO-OCT, those retinal structures that are not visible with AO or OCT alone (e.g., bundles of retinal nerve fiber layers, 3D mosaic of photoreceptors, 3D structure of microvasculature, and detailed structure of retinal disruptions) can be visualized. Our current AO-OCT instrumentation uses spectrometer-based Fourier-domain OCT technology and two-deformable-mirror-based AO wavefront correction. We describe image processing methods that help to remove motion artifacts observed in volumetric data, followed by innovative data visualization techniques [including two-dimensional (2D) and 3D representations]. Finally, examples of microscopic retinal structures that are acquired with the University of California Davis AO-OCT system are presented. PMID:17429483

  7. Proton Spectroscopic Factors Deduced from Helium-3 Global Phenomenological and Microscopic Optical Model Potentials

    NASA Astrophysics Data System (ADS)

    Jenny, Lee; Pang, Dan-Yang; Han, Yin-Lu; B. Tsang, M.

    2014-09-01

    Global phenomenological GDP08 and microscopic helium-3 optical model potentials have been recently derived. We evaluate these two potential sets by comparing the elastic scattering data of 25 MeV 3He on 16O, 18O, 19F, 23Na, 24Mg, 25Mg, 26Mg, 27Al, 28Si, 30Si, 31P, 32S, 34S, 35Cl, 37Cl, and 39K isotopes. Using the deuteron angular distributions calculated with the distorted wave Born approximation model, we extract the ground-state proton spectroscopic factors from (3He, d) reactions on the same set of nuclei. The extracted proton spectroscopic factors are compared with the large-basis shell-model calculations.

  8. Animated Optical Microscope Zoom in from Phoenix Launch to Martian Surface

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation

    This animated camera view zooms in from NASA's Phoenix Mars Lander launch site all the way to Phoenix's Microscopy and Electrochemistry and C Eonductivity Analyzer (MECA) aboard the spacecraft on the Martian surface. The final frame shows the soil sample delivered to MECA as viewed through the Optical Microscope (OM) on Sol 17 (June 11, 2008), or the 17th Martian day.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  9. Toolkit for the Automated Characterization of Optical Trapping Forces on Microscopic Particles

    NASA Astrophysics Data System (ADS)

    Glaser, Joseph; Hoeprich, David; Resnick, Andrew

    2014-03-01

    Optical traps have been in use in microbiological studies for the past 40 years to obtain noninvasive control of microscopic particles. However, the magnitude of the applied forces is often unknown. Therefore, we have developed an automated data acquisition and processing system which characterizes trap properties for known particle geometries. Extensive experiments and measurements utilizing well-characterized objects were performed and compared to literature to confirm the system's performance. This system will enable the future analysis of a trapped primary cilium, a slender rod-shaped organelle with aspect ratio L/R >30, where `L' is the cilium length and `R' the cilium diameter. The trapping of cilia is of primary importance, as it will lead to the precise measurements of mechanical properties of the organelle and its significance to the epithelial cell. Support from the National Institutes of Health, 1R15DK092716 is gratefully acknowledged.

  10. Animated Optical Microscope Zoom in from Phoenix Launch to Martian Surface

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation

    This animated camera view zooms in from NASA's Phoenix Mars Lander launch site all the way to Phoenix's Microscopy and Electrochemistry and C Eonductivity Analyzer (MECA) aboard the spacecraft on the Martian surface. The final frame shows the soil sample delivered to MECA as viewed through the Optical Microscope (OM) on Sol 17 (June 11, 2008), or the 17th Martian day.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  11. Analysis of the chicken retina with an adaptive optics multiphoton microscope.

    PubMed

    Bueno, Juan M; Giakoumaki, Anastasia; Gualda, Emilio J; Schaeffel, Frank; Artal, Pablo

    2011-06-01

    The structure and organization of the chicken retina has been investigated with an adaptive optics multiphoton imaging microscope in a backward configuration. Non-stained flat-mounted retinal tissues were imaged at different depths, from the retinal nerve fiber layer to the outer segment, by detecting the intrinsic nonlinear fluorescent signal. From the stacks of images corresponding to the different retinal layers, volume renderings of the entire retina were reconstructed. The density of photoreceptors and ganglion cells layer were directly estimated from the images as a function of the retinal eccentricity. The maximum anatomical resolving power at different retinal eccentricities was also calculated. This technique could be used for a better characterization of retinal alterations during myopia development, and may be useful for visualization of retinal pathologies and intoxication during pharmacological studies.

  12. Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

    NASA Astrophysics Data System (ADS)

    Labuda, Aleksander; Proksch, Roger

    2015-06-01

    An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community.

  13. Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

    SciTech Connect

    Labuda, Aleksander; Proksch, Roger

    2015-06-22

    An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community.

  14. Decoupling criterion based on limited energy loss condition for groove measurement using optical scanning microscopes

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Li, Mengzhou; Li, Qiang; Tan, Jiubin

    2016-12-01

    In confocal metrology, the lateral and axial responses are coupled in narrow regions near groove edges. This coupling results in an area with an uncertain profile, particularly for measurements of tight structures or deep grooves. In this paper, to delineate the area with measurement accuracy loss, an analytical model depicting the coupling relationships between the groove depth, the coupled portions and the NA of the objective used is introduced. Based on this model, the limited energy lost (LEL) decoupling criterion is presented that can enable users to choose suitable numerical apertures before performing measurements, predict the extents of the areas with measurement accuracy loss, and identify readout areas that yield accurate height measurements. The theory was verified by using confocal microscopes and is also applicable to far-field optical scanning metrology.

  15. Advantages of microscope-integrated intraoperative online optical coherence tomography: usage in Boston keratoprosthesis type I surgery

    NASA Astrophysics Data System (ADS)

    Siebelmann, Sebastian; Steven, Philipp; Hos, Deniz; Hüttmann, Gereon; Lankenau, Eva; Bachmann, Björn; Cursiefen, Claus

    2016-01-01

    Boston keratoprosthesis (KPro) type I is a technique to treat patients with corneal diseases that are not amenable to conventional keratoplasty. Correct assembly and central implantation of the prosthesis are crucial for postoperative visual recovery. This study investigates the potential benefit of intraoperative optical coherence tomography (OCT) to monitor KPro surgery. Retrospective case series are presented for two patients who underwent Boston KPro type I implantation. The surgery in both patients was monitored intraoperatively using a commercially available intraoperative OCT (iOCT) device mounted on a surgical microscope. Microscope-integrated intraoperative OCT was able to evaluate the correct assembly and implantation of the KPro. All parts of the prosthesis were visible, and interfaces between the corneal graft and titanium backplate or anterior optics were clearly depictable. Moreover, iOCT visualized a gap between the backplate and graft in one case, and in the other case, a gap between the anterior optic and graft. Neither gap was visible with a conventional surgical microscope. The gap between the anterior optic and the graft could easily be corrected. Microscope-integrated iOCT delivers enhanced information, adding to the normal surgical microscope view during KPro surgery. Correct assembly can be controlled as well as the correct placement of the Boston KPro into the anterior chamber.

  16. Quadrature phase interferometer used to calibrate dial indicator calibrators

    NASA Astrophysics Data System (ADS)

    Huang, Shau-Chi; Liou, Huay-Chung; Peng, Gwo-Sheng; Lu, Ming-Feng

    2001-10-01

    To calibrate dial indicators, gage blocks or dial indicator calibrators are usually used. For better accuracy and resolution, interferometers are used to calibrate dial indicator calibrators. Systematic errors of laser interferometers can be classified into three categories of intrinsic errors, environment errors and installation errors. Intrinsic errors include laser wavelength error, electronic error and optics nonlinearity. In order to achieve nanometer accuracy, minimizing intrinsic error is crucial. In this paper, we will address the problems of minimizing the optics nonlinearity error and describe the discrete-time signal processing method to minimize the electronic error, nonlinearity error and drift by simply using quadrature phase interferometer for nanometer accuracy and linearity.

  17. Optical scatter imaging: a microscopic modality for the rapid morphological assay of living cells

    NASA Astrophysics Data System (ADS)

    Boustany, Nada N.

    2007-02-01

    Tumors derived from epithelial cells comprise the majority of human tumors and their growth results from the accumulation of multiple mutations affecting cellular processes critical for tissue homeostasis, including cell proliferation and cell death. To understand these processes and address the complexity of cancer cell function, multiple cellular responses to different experimental conditions and specific genetic mutations must be analyzed. Fundamental to this endeavor is the development of rapid cellular assays in genetically defined cells, and in particular, the development of optical imaging methods that allow dynamic observation and real-time monitoring of cellular processes. In this context, we are developing an optical scatter imaging technology that is intended to bridge the gap between light and electron microscopy by rapidly providing morphometric information about the relative size and shape of non-spherical organelles, with sub-wavelength resolution. Our goal is to complement current microscopy techniques used to study cells in-vitro, especially in long-term time-lapse studies of living cells, where exogenous labels can be toxic, and electron microscopy will destroy the sample. The optical measurements are based on Fourier spatial filtering in a standard microscope, and could ultimately be incorporated into existing high-throughput diagnostic platforms for cancer cell research and histopathology of neoplastic tissue arrays. Using an engineered epithelial cell model of tumor formation, we are currently studying how organelle structure and function are altered by defined genetic mutations affecting the propensity for cell death and oncogenic potential, and by environmental conditions promoting tumor growth. This talk will describe our optical scatter imaging technology and present results from our studies on apoptosis, and the function of BCL-2 family proteins.

  18. Gaussian Quadrature Formulae for Arbitrary Positive Measures

    PubMed Central

    Fernandes, Andrew D.; Atchley, William R.

    2007-01-01

    We present computational methods and subroutines to compute Gaussian quadrature integration formulas for arbitrary positive measures. For expensive integrands that can be factored into well-known forms, Gaussian quadrature schemes allow for efficient evaluation of high-accuracy and -precision numerical integrals, especially compared to general ad hoc schemes. In addition, for certain well-known density measures (the normal, gamma, log-normal, Student’s t, inverse-gamma, beta, and Fisher’s F) we present exact formulae for computing the respective quadrature scheme. PMID:19455218

  19. Bright-field Nanoscopy: Visualizing Nano-structures with Localized Optical Contrast Using a Conventional Microscope

    PubMed Central

    Suran, Swathi; Bharadwaj, Krishna; Raghavan, Srinivasan; Varma, Manoj M.

    2016-01-01

    Most methods for optical visualization beyond the diffraction limit rely on fluorescence emission by molecular tags. Here, we report a method for visualization of nanostructures down to a few nanometers using a conventional bright-field microscope without requiring additional molecular tags such as fluorophores. The technique, Bright-field Nanoscopy, is based on the strong thickness dependent color of ultra-thin germanium on an optically thick gold film. We demonstrate the visualization of grain boundaries in chemical vapour deposited single layer graphene and the detection of single 40 nm Ag nanoparticles. We estimate a size detection limit of about 2 nm using this technique. In addition to visualizing nano-structures, this technique can be used to probe fluid phenomena at the nanoscale, such as transport through 2D membranes. We estimated the water transport rate through a 1 nm thick polymer film using this technique, as an illustration. Further, the technique can also be extended to study the transport of specific ions in the solution. It is anticipated that this technique will find use in applications ranging from single-nanoparticles resolved sensing to studying nanoscale fluid-solid interface phenomena. PMID:27112966

  20. Resonant scattering and microscopic model of spinless Fermi gases in one-dimensional optical lattices

    NASA Astrophysics Data System (ADS)

    Cui, Xiaoling

    2017-04-01

    We study the effective Bloch-wave scattering of a spinless Fermi gas in one-dimensional (1D) optical lattices. By tuning the odd-wave scattering length, we find multiple resonances of Bloch waves scattering at the bottom (and the top) of the lowest band, beyond which an attractive (and a repulsive) two-body bound state starts to emerge. These resonances exhibit comparable widths in the deep lattice limit, and the finite interaction range plays an essential role in determining their locations. Based on exact two-body solutions, we construct an effective microscopic model for the low-energy scattering of fermions. The model can reproduce not only the scattering amplitudes of Bloch waves at the lowest-band bottom or top, but also the attractive or repulsive bound states within a reasonably large energy range below or above the band. These results lay the foundation for quantum simulating topological states in cold Fermi gases confined in 1D optical lattices.

  1. Calculations of {sup 8}He+p elastic cross sections using a microscopic optical potential

    SciTech Connect

    Lukyanov, V. K.; Zemlyanaya, E. V.; Lukyanov, K. V.; Kadrev, D. N.; Antonov, A. N.; Gaidarov, M. K.; Massen, S. E.

    2009-08-15

    An approach to calculate microscopic optical potential with the real part obtained by a folding procedure and with the imaginary part inherent in the high-energy approximation is applied to study the {sup 8}He+p elastic-scattering data at energies of tens of MeV/nucleon. The neutron and proton density distributions obtained in different models for {sup 8}He are used in the calculations of the differential cross sections. The role of the spin-orbit potential is studied. Comparison of the calculations with the available experimental data on the elastic-scattering differential cross sections at beam energies of 15.7, 26.25, 32, 66, and 73 MeV/nucleon is performed. The problem of the ambiguities of the depths of each component of the optical potential is considered by means of the imposed physical criterion related to the known behavior of the volume integrals as functions of the incident energy. It is shown also that the role of the surface absorption is rather important, in particular for the lowest incident energies (e.g., 15.7 and 26.25 MeV/nucleon)

  2. Bright-field Nanoscopy: Visualizing Nano-structures with Localized Optical Contrast Using a Conventional Microscope

    NASA Astrophysics Data System (ADS)

    Suran, Swathi; Bharadwaj, Krishna; Raghavan, Srinivasan; Varma, Manoj M.

    2016-04-01

    Most methods for optical visualization beyond the diffraction limit rely on fluorescence emission by molecular tags. Here, we report a method for visualization of nanostructures down to a few nanometers using a conventional bright-field microscope without requiring additional molecular tags such as fluorophores. The technique, Bright-field Nanoscopy, is based on the strong thickness dependent color of ultra-thin germanium on an optically thick gold film. We demonstrate the visualization of grain boundaries in chemical vapour deposited single layer graphene and the detection of single 40 nm Ag nanoparticles. We estimate a size detection limit of about 2 nm using this technique. In addition to visualizing nano-structures, this technique can be used to probe fluid phenomena at the nanoscale, such as transport through 2D membranes. We estimated the water transport rate through a 1 nm thick polymer film using this technique, as an illustration. Further, the technique can also be extended to study the transport of specific ions in the solution. It is anticipated that this technique will find use in applications ranging from single-nanoparticles resolved sensing to studying nanoscale fluid-solid interface phenomena.

  3. Modeling a Miniaturized Scanning Electron Microscope Focusing Column - Lessons Learned in Electron Optics Simulation

    NASA Technical Reports Server (NTRS)

    Loyd, Jody; Gregory, Don; Gaskin, Jessica

    2016-01-01

    This presentation discusses work done to assess the design of a focusing column in a miniaturized Scanning Electron Microscope (SEM) developed at the NASA Marshall Space Flight Center (MSFC) for use in-situ on the Moon-in particular for mineralogical analysis. The MSFC beam column design uses purely electrostatic fields for focusing, because of the severe constraints on mass and electrical power consumption imposed by the goals of lunar exploration and of spaceflight in general. The resolution of an SEM ultimately depends on the size of the focused spot of the scanning beam probe, for which the stated goal here is a diameter of 10 nanometers. Optical aberrations are the main challenge to this performance goal, because they blur the ideal geometrical optical image of the electron source, effectively widening the ideal spot size of the beam probe. In the present work the optical aberrations of the mini SEM focusing column were assessed using direct tracing of non-paraxial rays, as opposed to mathematical estimates of aberrations based on paraxial ray-traces. The geometrical ray-tracing employed here is completely analogous to ray-tracing as conventionally understood in the realm of photon optics, with the major difference being that in electron optics the lens is simply a smoothly varying electric field in vacuum, formed by precisely machined electrodes. Ray-tracing in this context, therefore, relies upon a model of the electrostatic field inside the focusing column to provide the mathematical description of the "lens" being traced. This work relied fundamentally on the boundary element method (BEM) for this electric field model. In carrying out this research the authors discovered that higher accuracy in the field model was essential if aberrations were to be reliably assessed using direct ray-tracing. This led to some work in testing alternative techniques for modeling the electrostatic field. Ultimately, the necessary accuracy was attained using a BEM

  4. Microscope basics.

    PubMed

    Sluder, Greenfield; Nordberg, Joshua J

    2013-01-01

    This chapter provides information on how microscopes work and discusses some of the microscope issues to be considered in using a video camera on the microscope. There are two types of microscopes in use today for research in cell biology-the older finite tube-length (typically 160mm mechanical tube length) microscopes and the infinity optics microscopes that are now produced. The objective lens forms a magnified, real image of the specimen at a specific distance from the objective known as the intermediate image plane. All objectives are designed to be used with the specimen at a defined distance from the front lens element of the objective (the working distance) so that the image formed is located at a specific location in the microscope. Infinity optics microscopes differ from the finite tube-length microscopes in that the objectives are designed to project the image of the specimen to infinity and do not, on their own, form a real image of the specimen. Three types of objectives are in common use today-plan achromats, plan apochromats, and plan fluorite lenses. The concept of mounting video cameras on the microscope is also presented in the chapter.

  5. A multipurpose scanning near-field optical microscope: Reflectivity and photocurrent on semiconductor and biological samples

    NASA Astrophysics Data System (ADS)

    Cricenti, A.; Generosi, R.; Barchesi, C.; Luce, M.; Rinaldi, M.

    1998-09-01

    A multipurpose scanning near field optical microscope (SNOM) operating at ambient pressure is described with the aim of characterizing the inner parts of biological molecules and any semiconductor or metal microstructure. Therefore, in addition to the requirements of reliability and mechanical stability we have carefully considered analyzing a sample with all available geometries for input/output of photons, in order to get as much information as possible. The SNOM unit consists of two separable cylindrical supports; the lower one contains the sample holder mounted on top of a piezoelectric scanner which is contained in a motor controlled x-y-z stage. A piezo-modulated stretched optical fiber with a few tens of nanometer pinhole and a shear-force apparatus mounted inside the top cylinder allow for topography measurements. The reflectivity of the sample can be measured by applying different methods: the sample can be illuminated on top by an external source, as well as by the optical fiber used for the detection of the reflectivity signal. An aperture in the lower cylinder allows for illumination of the sample on the back: in this case the fiber collects the evanescent wave induced at the top of the sample. Another aperture in the lower cylinder allows measurement of the reflected light which includes a contribution due to the interaction with the fiber. Also photocurrent experiments can be easily performed by illuminating the sample with the fiber and detecting the transmitted signal using a current-voltage converter mounted inside the top cylinder. A video-camera that can reach 170 enlargements is mounted on the top cylinder for positioning the fiber on particular regions of the sample. Reflectivity and photocurrent measurements have been performed on uncoated neurons, CsI compound, Au/GaAs, and PtSi/Si systems, reaching a resolution well below the diffraction limit.

  6. Gaussian quadrature for multiple orthogonal polynomials

    NASA Astrophysics Data System (ADS)

    Coussement, Jonathan; van Assche, Walter

    2005-06-01

    We study multiple orthogonal polynomials of type I and type II, which have orthogonality conditions with respect to r measures. These polynomials are connected by their recurrence relation of order r+1. First we show a relation with the eigenvalue problem of a banded lower Hessenberg matrix Ln, containing the recurrence coefficients. As a consequence, we easily find that the multiple orthogonal polynomials of type I and type II satisfy a generalized Christoffel-Darboux identity. Furthermore, we explain the notion of multiple Gaussian quadrature (for proper multi-indices), which is an extension of the theory of Gaussian quadrature for orthogonal polynomials and was introduced by Borges. In particular, we show that the quadrature points and quadrature weights can be expressed in terms of the eigenvalue problem of Ln.

  7. Structured eigenvalue problems for rational gauss quadrature

    NASA Astrophysics Data System (ADS)

    Fasino, Dario; Gemignani, Luca

    2007-08-01

    The connection between Gauss quadrature rules and the algebraic eigenvalue problem for a Jacobi matrix was first exploited in the now classical paper by Golub and Welsch (Math. Comput. 23(106), 221?230, 1969). From then on many computational problems arising in the construction of (polynomial) Gauss quadrature formulas have been reduced to solving direct and inverse eigenvalue problems for symmetric tridiagonals. Over the last few years (rational) generalizations of the classical Gauss quadrature formulas have been studied, i.e., formulas integrating exactly in spaces of rational functions. This paper wants to illustrate that stable and efficient procedures based on structured numerical linear algebra techniques can also be devised for the solution of the eigenvalue problems arising in the field of rational Gauss quadrature.

  8. Design, Fabrication and Testing of Multilayer Coated X-Ray Optics for the Water Window Imaging X-Ray Microscope

    NASA Technical Reports Server (NTRS)

    Spencer, Dwight C.

    1996-01-01

    Hoover et. al. built and tested two imaging Schwarzschild multilayer microscopes. These instruments were constructed as prototypes for the "Water Window Imaging X-Ray Microscope," which is a doubly reflecting, multilayer x-ray microscope configured to operate within the "water window." The "water window" is the narrow region of the x-ray spectrum between the K absorption edges of oxygen (lamda = 23.3 Angstroms) and of carbon (lamda = 43.62 Angstroms), where water is relatively highly transmissive and carbon is highly absorptive. This property of these materials, thus permits the use of high resolution multilayer x-ray microscopes for producing high contrast images of carbon-based structures within the aqueous physiological environments of living cells. We report the design, fabrication and testing of multilayer optics that operate in this regime.

  9. A three-photon microscope with adaptive optics for deep-tissue in vivo structural and functional brain imaging

    NASA Astrophysics Data System (ADS)

    Tao, Xiaodong; Lu, Ju; Lam, Tuwin; Rodriguez, Ramiro; Zuo, Yi; Kubby, Joel

    2017-02-01

    We developed a three-photon adaptive optics add-on to a commercial two-photon laser scanning microscope. We demonstrated its capability for structural and functional imaging of neurons labeled with genetically encoded red fluorescent proteins or calcium indicators deep in the living mouse brain with cellular and subcellular resolution.

  10. Identification of unknown experimental parameters from noisy apertureless scanning near-field optical microscope data with an evolutionary procedure.

    PubMed

    Macías, D; Barchiesi, D

    2005-10-01

    We determine a set of experimental parameters through the application of an evolutionary inversion procedure. The input to the algorithm is experimental apertureless scanning near-field optical microscope data. The performance of our inversion procedure is assessed by means of a comparison with a nonevolutionary technique.

  11. Angular quadratures for improved transport computations

    SciTech Connect

    Abu-Shumays, I.K.

    1999-07-22

    This paper introduces new octant-range, composite-type Gauss and mid-point rule angular quadrature formulas for neutron and photon transport computations. A generalization to octant-range quadratures is also introduced in order to allow for discontinuities at material interfaces for two- and three-dimensional transport problems which can be modeled with 60-degree triangular or hexagonal mesh subdivisions in the x-y plane.

  12. Fast photoacoustic imaging with a line scanning optical-acoustical resolution photoacoustic microscope (LS-OAR-PAM)

    NASA Astrophysics Data System (ADS)

    Nuster, Robert; Paltauf, Guenther

    2015-07-01

    We present the concept, the setup and a preliminary experiment using optical ultrasound detection with a CCD camera combined with focused line excitation for photoacoustic microscopy. The line scanning optical-acoustical resolution photoacoustic microscope (LS-OAR-PAM) with optical ultrasound detection is capable of real-time B-scan imaging providing acoustical resolution within the individual B-scans and optical out of plane resolution up to a depth limited by optical diffusion. A 3D image is composed of reconstructed B-scan images recorded while scanning the excitation line along the sample surface. Proof of concept is shown by imaging a phantom containing black human hairs and carbon fibers. The obtained C-scan image clearly shows the different resolution in the two perpendicular directions, namely diffraction limited by optical focusing in scan direction and acoustically limited in direction parallel to line orientation by the properties of acoustic wave propagation.

  13. New tools for high-precision positioning of optical elements in high-NA microscope objectives

    NASA Astrophysics Data System (ADS)

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

    2004-02-01

    The precise positioning of the individual optical elements is essential for attaining diffraction limited performance in high-numerical-aperture (high-NA) microscope objectives. Tolerances are in the micron range or lower for high-end objectives, e.g. for broad-band scanning confocal applications, metrology objectives in general, and especially for deep ultraviolet (DUV) applications. The ever increasing demands on imaging performance ask for the continuous development and improvement of specialized measurement equipment for the production line. Our award-winning 150x/0.90-DUV-AT-infinity/0 objective for wafer inspection and metrology at 248nm employs air spacings in its doublets because of the instability of optical cements against DUV radiation. This comes however at the cost of a higher number of surfaces and even higher precision demands on their geometry, orientation and positioning. We present several tools enabling us to meet these requirements. A Fourier transform fringe analysis scheme is adapted to high-NA Fizeau interferometry for surface characterization. A white light Mirau interferometer for dimensional measurements on lens groups with sub-μm resolution enables us to keep surface distance errors lower than 2 μm. Residual aberrations of the objective are compensated for by translating special correction elements under observation of the wave-front using a DUV-Twyman-Green interferometer, which also incorporates a 903nm branch for the parfocal adjustment of the infrared (IR) autofocus feature of the objective. To adjust the shifting element for the elimination of on-axis coma, we compute an artificial (real-time) star test from the interferogram, allowing interactive manipulations of the element while monitoring their influence on the point spread function (PSF).

  14. Magnetic microscopic imaging with an optically pumped magnetometer and flux guides

    DOE PAGES

    Kim, Young Jin; Savukov, Igor Mykhaylovich; Huang, Jen -Huang; ...

    2017-01-23

    Here, by combining an optically pumped magnetometer (OPM) with flux guides (FGs) and by installing a sample platform on automated translation stages, we have implemented an ultra-sensitive FG-OPM scanning magnetic imaging system that is capable of detecting magnetic fields of ~20 pT with spatial resolution better than 300 μm (expected to reach ~10 pT sensitivity and ~100 μm spatial resolution with optimized FGs). As a demonstration of one possible application of the FG-OPM device, we conducted magnetic imaging of micron-size magnetic particles. Magnetic imaging of such particles, including nano-particles and clusters, is very important for many fields, especially for medicalmore » cancer diagnostics and biophysics applications. For rapid, precise magnetic imaging, we constructed an automatic scanning system, which holds and moves a target sample containing magnetic particles at a given stand-off distance from the FG tips. We show that the device was able to produce clear microscopic magnetic images of 10 μm-size magnetic particles. In addition, we also numerically investigated how the magnetic flux from a target sample at a given stand-off distance is transmitted to the OPM vapor cell.« less

  15. Hybrid metrology co-optimization of critical dimension scanning electron microscope and optical critical dimension

    NASA Astrophysics Data System (ADS)

    Vaid, Alok; Osorio, Carmen; Tsai, Jamie; Bozdog, Cornel; Sendelbach, Matthew; Grubner, Eyal; Koret, Roy; Wolfling, Shay

    2014-10-01

    Work using the concept of a co-optimization-based metrology hybridization is presented. Hybrid co-optimization involves the combination of data from two or more metrology tools such that the output of each tool is improved by the output of the other tool. Here, the image analysis parameters from a critical dimension scanning electron microscope (CD-SEM) are modulated by the profile information from optical critical dimension (OCD, or scatterometry), while the OCD-extracted profile is concurrently optimized through addition of the CD-SEM CD results. The test vehicle utilized is the 14-nm technology node-based FinFET high-k/interfacial layer (HK/IL) structure. When compared with the nonhybrid approach, the correlation to reference measurements of the HK layer thickness measurement using hybrid co-optimization resulted in an improvement in relative accuracy of about 40% and in R2 from 0.81 to 0.91. The measurement of the IL thickness also shows an improvement with hybrid co-optimization: better matching to the expected conditions as well as data that contain less noise.

  16. 4D microscope-integrated intraoperative optical coherence tomography angiography (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Viehland, Christian; Carrasco-Zevallos, Oscar; Keller, Brenton; Chen, Xi; Vajzovic, Lejla; Toth, Cynthia; Izatt, Joseph A.

    2017-02-01

    Optical coherence tomography (OCT) allows for micron scale imaging of the human retina and cornea. Previous research and commercial intraoperative OCT prototypes have been limited to live B-scan imaging because they were based on previous-generation spectral domain OCT systems. Our group has developed and reported on an intraoperative microscope integrated OCT system based on a 100 kHz commercial swept source laser. This system is capable of live 4D imaging, and with a heads up display allows for dynamic intraoperative visualization of retinal structures, tool tissue interaction, and surgical maneuvers. OCT angiography (OCTA) is an emerging OCT technology that allows for imaging of retinal vasculature without the use of potentially harmful contrast agents. This structural information can provide insights into the state and development of a wide range of ophthalmic pathologies. The addition of OCTA into intraoperative OCT could allow for monitoring of changes in retinal vasculature during surgery and imaging of traditionally non-compliant patients. In this work we provide a brief update of intraoperative 4D MIOCT across a range of pathologies, and demonstrate intraoperative OCTA for the first time. To the best of knowledge, this is the first report of intraoperative OCTA, as well as the first OCTA images ever acquired in an infant.

  17. Imaging of Interlayer Coupling in van der Waals Heterostructures Using a Bright-Field Optical Microscope.

    PubMed

    Alexeev, Evgeny M; Catanzaro, Alessandro; Skrypka, Oleksandr V; Nayak, Pramoda K; Ahn, Seongjoon; Pak, Sangyeon; Lee, Juwon; Sohn, Jung Inn; Novoselov, Kostya S; Shin, Hyeon Suk; Tartakovskii, Alexander I

    2017-09-13

    Vertically stacked atomic layers from different layered crystals can be held together by van der Waals forces, which can be used for building novel heterostructures, offering a platform for developing a new generation of atomically thin, transparent, and flexible devices. The performance of these devices is critically dependent on the layer thickness and the interlayer electronic coupling, influencing the hybridization of the electronic states as well as charge and energy transfer between the layers. The electronic coupling is affected by the relative orientation of the layers as well as by the cleanliness of their interfaces. Here, we demonstrate an efficient method for monitoring interlayer coupling in heterostructures made from transition metal dichalcogenides using photoluminescence imaging in a bright-field optical microscope. The color and brightness in such images are used here to identify mono- and few-layer crystals and to track changes in the interlayer coupling and the emergence of interlayer excitons after thermal annealing in heterobilayers composed of mechanically exfoliated flakes and as a function of the twist angle in atomic layers grown by chemical vapor deposition. Material and crystal thickness sensitivity of the presented imaging technique makes it a powerful tool for characterization of van der Waals heterostructures assembled by a wide variety of methods, using combinations of materials obtained through mechanical or chemical exfoliation and crystal growth.

  18. Magnetic microscopic imaging with an optically pumped magnetometer and flux guides

    NASA Astrophysics Data System (ADS)

    Kim, Young Jin; Savukov, Igor; Huang, Jen-Huang; Nath, Pulak

    2017-01-01

    By combining an optically pumped magnetometer (OPM) with flux guides (FGs) and by installing a sample platform on automated translation stages, we have implemented an ultra-sensitive FG-OPM scanning magnetic imaging system that is capable of detecting magnetic fields of ˜20 pT with spatial resolution better than 300 μm (expected to reach ˜10 pT sensitivity and ˜100 μm spatial resolution with optimized FGs). As a demonstration of one possible application of the FG-OPM device, we conducted magnetic imaging of micron-size magnetic particles. Magnetic imaging of such particles, including nano-particles and clusters, is very important for many fields, especially for medical cancer diagnostics and biophysics applications. For rapid, precise magnetic imaging, we constructed an automatic scanning system, which holds and moves a target sample containing magnetic particles at a given stand-off distance from the FG tips. We show that the device was able to produce clear microscopic magnetic images of 10 μm-size magnetic particles. In addition, we also numerically investigated how the magnetic flux from a target sample at a given stand-off distance is transmitted to the OPM vapor cell.

  19. Four-dimensional microscope- integrated optical coherence tomography to enhance visualization in glaucoma surgeries

    PubMed Central

    Pasricha, Neel Dave; Bhullar, Paramjit Kaur; Shieh, Christine; Viehland, Christian; Carrasco-Zevallos, Oscar Mijail; Keller, Brenton; Izatt, Joseph Adam; Toth, Cynthia Ann; Challa, Pratap; Kuo, Anthony Nanlin

    2017-01-01

    We report the first use of swept-source microscope-integrated optical coherence tomography (SS-MIOCT) capable of live four-dimensional (4D) (three-dimensional across time) imaging intraoperatively to directly visualize tube shunt placement and trabeculectomy surgeries in two patients with severe open-angle glaucoma and elevated intraocular pressure (IOP) that was not adequately managed by medical intervention or prior surgery. We performed tube shunt placement and trabeculectomy surgery and used SS-MIOCT to visualize and record surgical steps that benefitted from the enhanced visualization. In the case of tube shunt placement, SS-MIOCT successfully visualized the scleral tunneling, tube shunt positioning in the anterior chamber, and tube shunt suturing. For the trabeculectomy, SS-MIOCT successfully visualized the scleral flap creation, sclerotomy, and iridectomy. Postoperatively, both patients did well, with IOPs decreasing to the target goal. We found the benefit of SS-MIOCT was greatest in surgical steps requiring depth-based assessments. This technology has the potential to improve clinical outcomes. PMID:28300743

  20. Microscopic characteristics of the Ag(111)/ZnO(0001) interface present in optical coatings

    NASA Astrophysics Data System (ADS)

    Lin, Zheshuai; Bristowe, Paul D.

    2007-05-01

    A first-principles computational method is used to investigate the microscopic properties of the Ag(111)/ZnO(0001) interface that is often present in optical coatings designed for solar-control windows. The mechanical stability of the interface is important and therefore the ideal work of separation has been calculated for several structural variants of the interface which have different lattice mismatches and in-plane orientations. The process by which silver atoms are deposited, cluster, and form layers on the ZnO(0001) surface has also been studied. It is found that interfaces with the O-terminated ZnO surface are stronger than those with the Zn-terminated surface. In addition, incoherent interfaces with small lattice mismatch and minimal strain are preferred. In particular, the large period (9×8) Ag/ZnO coincidence superstructure (0.1% mismatch) is found to have a significantly higher work of separation than the coherent (1×1) interface (11% mismatch). A rotated variant of the interface (2×√3) R30 (2.6% mismatch) has a work of separation that is comparable with the coincidence superstructure. Both the (9×8) and (2×√3) R30 Ag/ZnO interfaces have been observed in deposition experiments and which one is seen depends on the ambient conditions and strain state of the interface. The calculated works of separation are consistent with measured works of adhesion obtained from cantilever beam experiments.

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  2. Development and optical testing of the camera, hand lens, and microscope probe with scannable laser spectroscopy (CHAMP-SLS)

    NASA Astrophysics Data System (ADS)

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

    2008-08-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  4. Past and Future SOHO-Ulysses Quadratures

    NASA Technical Reports Server (NTRS)

    Suess, Steven; Poletto, G.

    2006-01-01

    With the launch of SOHO, it again became possible to carry out quadrature observations. In comparison with earlier observations, the new capabilities of coronal spectroscopy with UVCS and in situ ionization state and composition with Ulysses/SWICS enabled new types of studies. Results from two studies serve as examples: (i) The acceleration profile of wind from small coronal holes. (ii) A high-coronal reconnecting current sheet as the source of high ionization state Fe in a CME at Ulysses. Generally quadrature observations last only for a few days, when Ulysses is within ca. 5 degrees of the limb. This means luck is required for the phenomenon of interest to lie along the radial direction to Ulysses. However, when Ulysses is at high southern latitude in winter 2007 and high northern latitude in winter 2008, there will be unusually favorable configurations for quadrature observations with SOHO and corresponding bracketing limb observations from STEREO A/B. Specifically, Ulysses will be within 5 degrees of the limb from December 2006 to May 2007 and within 10 degrees of the limb from December 2007 to May 2008. These long-lasting quadratures and bracketing STEREO A/B observations overcome the limitations inherent in the short observation intervals of typical quadratures. Furthermore, ionization and charge state measurements like those on Ulysses will also be made on STEREO and these will be essential for identification of CME ejecta - one of the prime objectives for STEREO.

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

    SciTech Connect

    Santamaria, L.; Siller, H. R.; Garcia-Ortiz, C. E.; Cortes, R.; Coello, V.

    2016-04-15

    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.

  6. Analysis of Zebrafish Kidney Development with Time-lapse Imaging Using a Dissecting Microscope Equipped for Optical Sectioning.

    PubMed

    Perner, Birgit; Schnerwitzki, Danny; Graf, Michael; Englert, Christoph

    2016-04-07

    In order to understand organogenesis, the spatial and temporal alterations that occur during development of tissues need to be recorded. The method described here allows time-lapse analysis of normal and impaired kidney development in zebrafish embryos by using a fluorescence dissecting microscope equipped for structured illumination and z-stack acquisition. To visualize nephrogenesis, transgenic zebrafish (Tg(wt1b:GFP)) with fluorescently labeled kidney structures were used. Renal defects were triggered by injection of an antisense morpholino oligonucleotide against the Wilms tumor gene wt1a, a factor known to be crucial for kidney development. The advantage of the experimental setup is the combination of a zoom microscope with simple strategies for re-adjusting movements in x, y or z direction without additional equipment. To circumvent focal drift that is induced by temperature variations and mechanical vibrations, an autofocus strategy was applied instead of utilizing a usually required environmental chamber. In order to re-adjust the positional changes due to a xy-drift, imaging chambers with imprinted relocation grids were employed. In comparison to more complex setups for time-lapse recording with optical sectioning such as confocal laser scanning or light sheet microscopes, a zoom microscope is easy to handle. Besides, it offers dissecting microscope-specific benefits such as high depth of field and an extended working distance. The method to study organogenesis presented here can also be used with fluorescence stereo microscopes not capable of optical sectioning. Although limited for high-throughput, this technique offers an alternative to more complex equipment that is normally used for time-lapse recording of developing tissues and organ dynamics.

  7. Analysis of Zebrafish Kidney Development with Time-lapse Imaging Using a Dissecting Microscope Equipped for Optical Sectioning

    PubMed Central

    Perner, Birgit; Schnerwitzki, Danny; Graf, Michael; Englert, Christoph

    2016-01-01

    In order to understand organogenesis, the spatial and temporal alterations that occur during development of tissues need to be recorded. The method described here allows time-lapse analysis of normal and impaired kidney development in zebrafish embryos by using a fluorescence dissecting microscope equipped for structured illumination and z-stack acquisition. To visualize nephrogenesis, transgenic zebrafish (Tg(wt1b:GFP)) with fluorescently labeled kidney structures were used. Renal defects were triggered by injection of an antisense morpholino oligonucleotide against the Wilms tumor gene wt1a, a factor known to be crucial for kidney development. The advantage of the experimental setup is the combination of a zoom microscope with simple strategies for re-adjusting movements in x, y or z direction without additional equipment. To circumvent focal drift that is induced by temperature variations and mechanical vibrations, an autofocus strategy was applied instead of utilizing a usually required environmental chamber. In order to re-adjust the positional changes due to a xy-drift, imaging chambers with imprinted relocation grids were employed. In comparison to more complex setups for time-lapse recording with optical sectioning such as confocal laser scanning or light sheet microscopes, a zoom microscope is easy to handle. Besides, it offers dissecting microscope-specific benefits such as high depth of field and an extended working distance. The method to study organogenesis presented here can also be used with fluorescence stereo microscopes not capable of optical sectioning. Although limited for high-throughput, this technique offers an alternative to more complex equipment that is normally used for time-lapse recording of developing tissues and organ dynamics. PMID:27078207

  8. Micro-electro-fluidic module to control magnetotactic bacteria for micromanipulation tasks under an optical microscope

    NASA Astrophysics Data System (ADS)

    André, Walder; Lu, Zhao; Moufarrej, Bechara; Martel, Sylvain

    2007-10-01

    This project describes a Multi-Chip Module (MCM) that contains a microelectronic circuit and a microfluidic device that could be combined to implement a "bacterial microfactory". The microchip contains two decoders connected to arrays of horizontal and vertical wires respectively, forming a matrix used to process commands received from an external computer. The electrical current flowing through the matrix is generated from internal voltage-to-current converters. The electrical current circulating through a metal conductor generates a magnetic field that is used to guide the movement of Magnetotactic Bacteria (MTB) in the microfluidic device. The dedicated microfluidic device is micro-fabricated on a glass wafer. Preliminary results show that a single MC-1 MTB can push a 2 μm microbead at speeds reaching 100μm/s under the control of an external magnetic field of less than 10 Gauss. A Carl Zeiss microscopy software (AxioVision) is used to control and configure the Axio Imager Z1 optical microscope and allows us to develop customized plug-in with Visual Basic for Application (VBA). The control electronic die was hence programmed as a VBA module, simplifying interoperability between the control, data recordings and microscopy observations. The parallel port of an Intel Pentium 4, 3.0 GHz equipped with 2.87 Go of RAM running Windows XP was used to communicate with the circuit. Connected to the parallel port, two demultiplexers interface the chip and the port. Patterns to control the bacteria such as left-right and up-down displacements were implemented and tested. Other more complex patterns to capture, attract and repel the bacteria from the center of the chip were also designed and validated.

  9. Theory of the quadrature elliptic birdcage coil.

    PubMed

    Leifer, M C

    1997-11-01

    This paper presents the theory of the quadrature birdcage coil wound on an elliptic cylindrical former. A conformal transformation of the ellipse to a circular geometry is used to derive the optimal sampling of the continuous surface current distribution to produce uniform magnetic fields within an elliptic cylinder. The analysis is rigorous for ellipses of any aspect ratio and shows how to produce quadrature operation of the elliptic birdcage with a conventional hybrid combiner. Insight gained from the transformation is also used to analyze field homogeneity, find the optimal RF shield shape, and specify component values to produce the correct current distribution in practice. Measurements and images from a 16-leg elliptic birdcage coil at both low and high frequencies show good quadrature performance, homogeneity, and sensitivity.

  10. Imaging of quantum Hall edge states under quasiresonant excitation by a near-field scanning optical microscope

    SciTech Connect

    Ito, H.; Shibata, Y.; Mamyoda, S.; Ootuka, Y.; Nomura, S.; Kashiwaya, S.; Yamaguchi, M.; Akazaki, T.; Tamura, H.

    2013-12-04

    A high resolution mapping of quantum Hall edge states has been performed by locally creating electrons with small excess energies with a near-field scanning optical microscope in a dilution refrigerator. We have observed fine structures parallel to the edge in photovoltage signals, which appear only at low temperature. The observed fine structures near sample edges have been seen to shift inward with increase in magnetic field in accordance with Chklovskii Shklovskii, and Glazman model.

  11. In-situ optical transmission electron microscope study of exciton phonon replicas in ZnO nanowires by cathodoluminescence

    SciTech Connect

    Yang, Shize; Tian, Xuezeng; Wang, Lifen; Wei, Jiake; Qi, Kuo; Li, Xiaomin; Xu, Zhi E-mail: xdbai@iphy.ac.cn Wang, Wenlong; Zhao, Jimin; Bai, Xuedong E-mail: xdbai@iphy.ac.cn; Wang, Enge E-mail: xdbai@iphy.ac.cn

    2014-08-18

    The cathodoluminescence spectrum of single zinc oxide (ZnO) nanowires is measured by in-situ optical Transmission Electron Microscope. The coupling between exciton and longitudinal optical phonon is studied. The band edge emission varies for different excitation spots. This effect is attributed to the exciton propagation along the c axis of the nanowire. Contrary to free exciton emission, the phonon replicas are well confined in ZnO nanowire. They travel along the c axis and emit at the end surface. Bending strain increases the relative intensity of second order phonon replicas when excitons travel along the c-axis.

  12. Numerical analysis of the transmission efficiency of heat-drawn and chemically etched scanning near-field optical microscopes.

    PubMed

    Moar, P; Ladouceur, F; Cahill, L

    2000-04-20

    The scanning near-field optical microscope (SNOM) has been tested experimentally for a wide variety of applications, but, to date, there has been little work done on the numerical or analytical modeling of the optical field as it propagates throughout the SNOM probe. Therefore, the fabrication on the probes relies more on trial and error than on clear design principles. An algorithm has been developed for the study and optimization of the geometry of SNOM probes fabricated by the heat-drawn and the one-step chemically etched methods. The algorithm uses the finite-difference beam propagation method (FD-BPM) to model the field evolution throughout the SNOM structure.

  13. Angle of incidence averaging in reflectance measurements with optical microscopes for studying layered two-dimensional materials.

    PubMed

    Saigal, Nihit; Mukherjee, Amlan; Sugunakar, Vasam; Ghosh, Sandip

    2014-07-01

    Reflectance spectrum measured using an optical microscope with a large numerical aperture objective lens is shown to get modified. The change is most prominent when there are optical interference related features in the spectrum. This modification is shown to arise primarily due to the wide range of angles of incidence involved in the measurement and a simple formulation is provided to correct for this in simulations. The importance of such analysis is brought out through a reflectance contrast spectroscopy based study for identifying mono-layer and bi-layer graphene and MoS2.

  14. Photon path distribution and optical responses of turbid media: theoretical analysis based on the microscopic Beer-Lambert law.

    PubMed

    Tsuchiya, Y

    2001-08-01

    A concise theoretical treatment has been developed to describe the optical responses of a highly scattering inhomogeneous medium using functions of the photon path distribution (PPD). The treatment is based on the microscopic Beer-Lambert law and has been found to yield a complete set of optical responses by time- and frequency-domain measurements. The PPD is defined for possible photons having a total zigzag pathlength of l between the points of light input and detection. Such a distribution is independent of the absorption properties of the medium and can be uniquely determined for the medium under quantification. Therefore, the PPD can be calculated with an imaginary reference medium having the same optical properties as the medium under quantification except for the absence of absorption. One of the advantages of this method is that the optical responses, the total attenuation, the mean pathlength, etc are expressed by functions of the PPD and the absorption distribution.

  15. Dual-modal three-dimensional imaging of single cells with isometric high resolution using an optical projection tomography microscope

    NASA Astrophysics Data System (ADS)

    Miao, Qin; Rahn, J. Richard; Tourovskaia, Anna; Meyer, Michael G.; Neumann, Thomas; Nelson, Alan C.; Seibel, Eric J.

    2009-11-01

    The practice of clinical cytology relies on bright-field microscopy using absorption dyes like hematoxylin and eosin in the transmission mode, while the practice of research microscopy relies on fluorescence microscopy in the epi-illumination mode. The optical projection tomography microscope is an optical microscope that can generate 3-D images of single cells with isometric high resolution both in absorption and fluorescence mode. Although the depth of field of the microscope objective is in the submicron range, it can be extended by scanning the objective's focal plane. The extended depth of field image is similar to a projection in a conventional x-ray computed tomography. Cells suspended in optical gel flow through a custom-designed microcapillary. Multiple pseudoprojection images are taken by rotating the microcapillary. After these pseudoprojection images are further aligned, computed tomography methods are applied to create 3-D reconstruction. 3-D reconstructed images of single cells are shown in both absorption and fluorescence mode. Fluorescence spatial resolution is measured at 0.35 μm in both axial and lateral dimensions. Since fluorescence and absorption images are taken in two different rotations, mechanical error may cause misalignment of 3-D images. This mechanical error is estimated to be within the resolution of the system.

  16. Summation Paths in Clenshaw-Curtis Quadrature

    NASA Astrophysics Data System (ADS)

    Adam, S.; Adam, Gh.

    2016-02-01

    Two topics concerning the use of Clenshaw-Curtis quadrature within the Bayesian automatic adaptive quadrature approach to the numerical solution of Riemann integrals are considered. First, it is found that the efficient floating point computation of the coefficients of the Chebyshev series expansion of the integrand is to be done within a mathematical structure consisting of the union of coefficient families ordered into complete binary trees. Second, the scrutiny of the decay rates of the involved even and odd rank Chebyshev expansion coefficients with the increase of their rank labels enables the definition of Bayesian decision paths for the advancement to the numerical output.

  17. Dual-quadrature coherent receiver for 100G Ethernet applications based on polymer planar lightwave circuit.

    PubMed

    Wang, Jin; Kroh, Marcel; Theurer, Abongwa; Zawadzki, Crispin; Schmidt, Detlef; Ludwig, Reinhold; Lauermann, Matthias; Zhang, Ziyang; Beling, Andreas; Matiss, Andreas; Schubert, Colja; Steffan, Andreas; Keil, Norbert; Grote, Norbert

    2011-12-12

    A dual-quadrature coherent receiver based on a polymer planar lightwave circuit (PLC) is presented. This receiver comprises two separate optical 90°-hybrid chips made of polymer waveguides and hybridly integrated with InGaAs/InP photodiode (PD) arrays. The packaged receiver was successfully operated in 112 Gbit/s dual-polarization quadrature phase-shift keying (QPSK) transmission experiments. In back-to-back configuration the OSNR requirement for a BER value of 10(-3) was 15.1 dB which has to be compared to a theoretical limit of 13.8 dB.

  18. A fiber-optic fluorescence microscope using a consumer-grade digital camera for in vivo cellular imaging.

    PubMed

    Shin, Dongsuk; Pierce, Mark C; Gillenwater, Ann M; Williams, Michelle D; Richards-Kortum, Rebecca R

    2010-06-23

    Early detection is an essential component of cancer management. Unfortunately, visual examination can often be unreliable, and many settings lack the financial capital and infrastructure to operate PET, CT, and MRI systems. Moreover, the infrastructure and expense associated with surgical biopsy and microscopy are a challenge to establishing cancer screening/early detection programs in low-resource settings. Improvements in performance and declining costs have led to the availability of optoelectronic components, which can be used to develop low-cost diagnostic imaging devices for use at the point-of-care. Here, we demonstrate a fiber-optic fluorescence microscope using a consumer-grade camera for in vivo cellular imaging. The fiber-optic fluorescence microscope includes an LED light, an objective lens, a fiber-optic bundle, and a consumer-grade digital camera. The system was used to image an oral cancer cell line labeled with 0.01% proflavine. A human tissue specimen was imaged following surgical resection, enabling dysplastic and cancerous regions to be evaluated. The oral mucosa of a healthy human subject was imaged in vivo, following topical application of 0.01% proflavine. The fiber-optic microscope resolved individual nuclei in all specimens and tissues imaged. This capability allowed qualitative and quantitative differences between normal and precancerous or cancerous tissues to be identified. The optical efficiency of the system permitted imaging of the human oral mucosa in real time. Our results indicate this device as a useful tool to assist in the identification of early neoplastic changes in epithelial tissues. This portable, inexpensive unit may be particularly appropriate for use at the point-of-care in low-resource settings.

  19. Optical metrology of nano-scale mineral dissolutions using a phase-shift interference microscope

    NASA Astrophysics Data System (ADS)

    Satoh, H.; Nishimura, Y.; Tsukamoto, K.; Ueda, A.; Ueta, S.; Kato, K.

    2005-12-01

    Solid materials are greater or less soluble on the Earth's surface environment in nano-scale. Dissolution is critical issue for weathering and geo-environmental assessment. Recent advances in nanoscopy are derived from novel topographic method with scanning probe microscopes (AFM, STM, LCM). As another classical but precise method, interferometry is still useful optical tool and enables quick and easy survey of vertical surface topography by utilizing computer processing. We have newly designed a white-light phase-shift interference microscope (PSI-M) for detecting ultra-slow dissolution and precipitation to validate the endurance of artificial barrier system for radioactive waste repository (Ueda et al., 2005) and assess the geologic CO2 storage system. The measurement system is comprised of Maki-type (modified Michelson) phase-shift interferometer, white light source, computer camera, and Ti reaction cell with syringe pump. Minimum resolutions are calculated to be about 0.7 nm for surface-reflection mode and 6.6 nm for back-reflection mode. It takes only 2 s to obtain a phase-shift interferogram. After sequential image acquisitions, we can measure the rates of advance and retreat in real-time at the surface of the specimen in the view field by image-processing. As a benchmark test of surface reflection mode, we carried out a dissolution experiment on BK7 glass in pure H2O flowing at 105 um/s. Result showed 8.7E-5 nm/s of dissolution velocity, corresponding to a rate of ~3um/yr . Measurement at etch pits on calcite (10-14) in pure H2O showed an acceptable dissolution rate of 2.9E-10 mol/cm2/s (Ueda et al., 2005). Another measurement on anorthite (010) in 0.5M of NaCl-NaOH-HCl solutions at 105 um/s flow showed consistent rates of 2.4E-13 to 2.3E-11 mol/cm2/s at pH = 3-12.4 with the previous data (Blum and Stillings, 1995). These results sufficiently confirmed precision of the rate determination with PSI-M. We have further carried out the dissolution measurement on

  20. An evaluation of a combined scanning probe and optical microscope for lunar regolith studies

    NASA Astrophysics Data System (ADS)

    Yang, S.; Pike, W. T.; Staufer, U.; Claus, D.; Rodenburg, J. M.

    2011-12-01

    The microscopic properties of the lunar regolith such as the shape, the surface texture and the size distribution are required for an understanding of both past surface processes and potential hazards for future human exploration [1]. To reveal the particle morphology at the sub micrometer scale, scanning-probe microscopy (SPM), first used on the 2008 Phoenix mission [1], is a proven approach; however, there are two main challenges for the measurement of lunar particles. Firstly, the SPM tip is liable to move particles during scanning, even when using the lower contact forces of the dynamic-mode imaging. Hence the particles need to be stabilised during imaging. Secondly, typically the AFM tip extends about 10 μm from its cantilever, so larger particles protruding more than this height above their substrates cannot be scanned completely. To immobilize particles and eliminate large particles during SPM scanning, micromachined Si substrates, which have been successfully applied in the Phoenix project for Mars investigation in 2008 [2], have been investigated for lunar analogue material. On these substrates micrometer pits are patterned and serve as traps to enhance the stability of the AFM scanning by grasping the particles. In addition, the diameter of pits can determine the size of dusts to be captured and reduce the adhesion for the larger dust and so eliminate the oversized particles. To extend the imaging range and assist in selecting scan areas for the SPM, we use a type of lensless optical imaging (LOM) which uses ptychographic diffractive imaging [3] to eliminate the restrictions and performance limitations of conventional focusing devices. As a reference, scanning electron microscopy (SEM) which minimizes particle-probe interactions and has the advantage of an extended depth of field, is employed to image the same particle fields at resolutions covering both the SPM and LOM. By comparing the differences and the similarities between SEM and LOM images, the

  1. Composite Gauss-Legendre Quadrature with Error Control

    ERIC Educational Resources Information Center

    Prentice, J. S. C.

    2011-01-01

    We describe composite Gauss-Legendre quadrature for determining definite integrals, including a means of controlling the approximation error. We compare the form and performance of the algorithm with standard Newton-Cotes quadrature. (Contains 1 table.)

  2. Composite Gauss-Legendre Quadrature with Error Control

    ERIC Educational Resources Information Center

    Prentice, J. S. C.

    2011-01-01

    We describe composite Gauss-Legendre quadrature for determining definite integrals, including a means of controlling the approximation error. We compare the form and performance of the algorithm with standard Newton-Cotes quadrature. (Contains 1 table.)

  3. Optofluidic microscopy--a method for implementing a high resolution optical microscope on a chip.

    PubMed

    Heng, Xin; Erickson, David; Baugh, L Ryan; Yaqoob, Zahid; Sternberg, Paul W; Psaltis, Demetri; Yang, Changhuei

    2006-10-01

    We report a novel microfluidics-based lensless imaging technique, termed optofluidic microscopy (OFM), and demonstrate Caenorhabditis elegans imaging with an OFM prototype that gives comparable resolution to a conventional microscope and a measured resolution limit of 490 +/- 40 nm.

  4. Nuclear data evaluation of long-lived fission products: Microscopic vs. phenomenological optical potentials

    NASA Astrophysics Data System (ADS)

    Minato, Futoshi; Iwamoto, Osamu; Minomo, Kosho; Ogata, Kazuyuki; Iwamoto, Nobuyuki; Kunieda, Satoshi; Furutachi, Naoya

    2017-09-01

    Neutron-nucleus cross sections calculated by macroscopic potentials are compared with a microscopic one to study the performance for long-lived fission products. The macroscopic potentials show a good agreement with the microscopic one at higher energies, where neutron experimental data are scarce. Besides it, analyses of differential elastic cross sections at low energies also suggest that the macroscopic potentials are still effective and applicable enough for the long-lived fission products.

  5. Multimodal optical setup for nonlinear and fluorescence lifetime imaging microscopies: improvement on a commercial confocal inverted microscope

    NASA Astrophysics Data System (ADS)

    Pelegati, V. B.; Adur, J.; de Thomaz, A. A.; Almeida, D. B.; Baratti, M. O.; Carvalho, H. F.; Cesar, C. L.

    2012-03-01

    In this work we proposed and built a multimodal optical setup that extends a commercially available confocal microscope (Olympus FV300) to include nonlinear optical (NLO) microscopy and fluorescence lifetime imaging microscopy (FLIM). The NLO microscopies included two-photon fluorescence (TPFE), Second Harmonic Generation (SHG) and Third Harmonic Generation (THG). The whole system, including FLIM, used only one laser source composed of an 80 MHz femtosecond laser. The commercial Ti:sapphire lasers can be tuned up to 690-1040 nm bringing the THG signal to the 350 nm region where most microscope optics do not work. However, the third harmonic is only generated at the sample, meaning that we only have to take care of the collection optics. To do that we used a remote photomultiplier to acquire the THG signal at the 310-350 nm wavelength window. After performing the tests to guarantee that we are observing actually SHG/THG signals we than used this system to acquire multimodal images of several biological samples, from epithelial cancer to vegetables. The ability to see the collagen network together with the cell nuclei proved to be important for cancer tissues diagnosis. Moreover, FLIM provides information about the cell metabolism, also very important for cancer cell processes.

  6. Comparison of two Galerkin quadrature methods

    DOE PAGES

    Morel, Jim E.; Warsa, James; Franke, Brian C.; ...

    2017-02-21

    Here, we compare two methods for generating Galerkin quadratures. In method 1, the standard SN method is used to generate the moment-to-discrete matrix and the discrete-to-moment matrix is generated by inverting the moment-to-discrete matrix. This is a particular form of the original Galerkin quadrature method. In method 2, which we introduce here, the standard SN method is used to generate the discrete-to-moment matrix and the moment-to-discrete matrix is generated by inverting the discrete-to-moment matrix. With an N-point quadrature, method 1 has the advantage that it preserves N eigenvalues and N eigenvectors of the scattering operator in a pointwise sense. Withmore » an N-point quadrature, method 2 has the advantage that it generates consistent angular moment equations from the corresponding SN equations while preserving N eigenvalues of the scattering operator. Our computational results indicate that these two methods are quite comparable for the test problem considered.« less

  7. Thin-thick quadrature frequency conversion

    SciTech Connect

    Eimerl, D.

    1985-02-07

    The quadrature conversion scheme is a method of generating the second harmonic. The scheme, which uses two crystals in series, has several advantages over single-crystal or other two crystal schemes. The most important is that it is capable of high conversion efficiency over a large dynamic range of drive intensity and detuning angle.

  8. Quadrature phase interferometer for high resolution force spectroscopy

    SciTech Connect

    Paolino, Pierdomenico; Aguilar Sandoval, Felipe A.; Bellon, Ludovic

    2013-09-15

    In this article, we present a deflection measurement setup for Atomic Force Microscopy (AFM). It is based on a quadrature phase differential interferometer: we measure the optical path difference between a laser beam reflecting above the cantilever tip and a reference beam reflecting on the static base of the sensor. A design with very low environmental susceptibility and another allowing calibrated measurements on a wide spectral range are described. Both enable a very high resolution (down to 2.5×10{sup −15} m/√(Hz)), illustrated by thermal noise measurements on AFM cantilevers. They present an excellent long-term stability and a constant sensitivity independent of the optical phase of the interferometer. A quick review shows that our precision is equaling or out-performing the best results reported in the literature, but for a much larger deflection range, up to a few μm.

  9. Error Bounds for Quadrature Methods Involving Lower Order Derivatives

    ERIC Educational Resources Information Center

    Engelbrecht, Johann; Fedotov, Igor; Fedotova, Tanya; Harding, Ansie

    2003-01-01

    Quadrature methods for approximating the definite integral of a function f(t) over an interval [a,b] are in common use. Examples of such methods are the Newton-Cotes formulas (midpoint, trapezoidal and Simpson methods etc.) and the Gauss-Legendre quadrature rules, to name two types of quadrature. Error bounds for these approximations involve…

  10. Error Bounds for Quadrature Methods Involving Lower Order Derivatives

    ERIC Educational Resources Information Center

    Engelbrecht, Johann; Fedotov, Igor; Fedotova, Tanya; Harding, Ansie

    2003-01-01

    Quadrature methods for approximating the definite integral of a function f(t) over an interval [a,b] are in common use. Examples of such methods are the Newton-Cotes formulas (midpoint, trapezoidal and Simpson methods etc.) and the Gauss-Legendre quadrature rules, to name two types of quadrature. Error bounds for these approximations involve…

  11. a Scanning Near-Field Optical Microscope with Magneto-Optic Kerr Effect Contrast for the Imaging of Magnetic Domains with 200 Angstrom Resolution

    NASA Astrophysics Data System (ADS)

    Silva, Thomas Joseph

    We describe the development of a scanning near -field optical microscope for magnetic domain imaging in thin-film materials. The near-field probe is a 20-40 nm Ag particle which is optically excited near the surface plasmon resonance frequency. The plasmon resonance in individual Ag particles is characterized by optical spectroscopy for light scattered from single Ag particles. The existence of a near-field form of the magneto-optic Kerr effect is confirmed. In the final form of the microscope, the Ag particle is mounted on a hemispherical glass substrate and brought to within near-field proximity of a flat sample surface. The separation of the probe and sample is regulated by a Newton ring interferometer in closed loop feedback control of a piezoelectric translator. Separation stability can be kept to less than one nanometer. Near-field magneto -optic interactions are measured with a shot-noise limited modulating ellipsometer. We measured the dependence of the near-field Kerr signal on the separation of the probe and sample for longitudinal magnetization, and suggest a potential resolution of 20-40 nm. Two-dimensional images are presented of thermo-magnetically recorded domains in a Co/Pt multilayer material, with less than 100 nm resolution. Domains with a 0.5 micron diameter and one micron spacing are clearly resolved. We discuss future improvements of the instrument and propose an ultimate resolution of 140 A.

  12. Tracking sub-micron fluorescent particles in three dimensions with a microscope objective under non-design optical conditions

    NASA Astrophysics Data System (ADS)

    Luo, R.; Sun, Y. F.; Peng, X. F.; Yang, X. Y.

    2006-06-01

    A microscope objective designed for air medium has been used under non-design optical conditions to focus an exciting laser beam on sub-micron fluorescent particles with the emitted fluorescence received through a glass layer with a mismatched refractive index. The diffraction pattern with several clear interference fringes generated from the fluorescence emitted from a fluorescent particle changed with the particle's position along the optical axis. A scalar diffraction model developed by Gibson and Lanni (1991 J. Opt. Soc. Am. A 8 1601-13) was used to predict the diffraction patterns for various aberration conditions and to analyse the effects of the coherence properties of the fluorescence on the details of the diffraction pattern. The particle position along the optical axis, i.e. its defocus distance, could be determined based on the characteristic sizes of the particle's diffraction pattern to track the particle in three dimensions.

  13. Three-dimensional reconstruction of highly complex microscopic samples using scanning electron microscopy and optical flow estimation

    PubMed Central

    Pahlavan Tafti, Ahmad; Owen, Heather A.; D’Souza, Roshan M.; Yu, Zeyun

    2017-01-01

    Scanning Electron Microscope (SEM) as one of the major research and industrial equipment for imaging of micro-scale samples and surfaces has gained extensive attention from its emerge. However, the acquired micrographs still remain two-dimensional (2D). In the current work a novel and highly accurate approach is proposed to recover the hidden third-dimension by use of multi-view image acquisition of the microscopic samples combined with pre/post-processing steps including sparse feature-based stereo rectification, nonlocal-based optical flow estimation for dense matching and finally depth estimation. Employing the proposed approach, three-dimensional (3D) reconstructions of highly complex microscopic samples were achieved to facilitate the interpretation of topology and geometry of surface/shape attributes of the samples. As a byproduct of the proposed approach, high-definition 3D printed models of the samples can be generated as a tangible means of physical understanding. Extensive comparisons with the state-of-the-art reveal the strength and superiority of the proposed method in uncovering the details of the highly complex microscopic samples. PMID:28384216

  14. Three-dimensional reconstruction of highly complex microscopic samples using scanning electron microscopy and optical flow estimation.

    PubMed

    Baghaie, Ahmadreza; Pahlavan Tafti, Ahmad; Owen, Heather A; D'Souza, Roshan M; Yu, Zeyun

    2017-01-01

    Scanning Electron Microscope (SEM) as one of the major research and industrial equipment for imaging of micro-scale samples and surfaces has gained extensive attention from its emerge. However, the acquired micrographs still remain two-dimensional (2D). In the current work a novel and highly accurate approach is proposed to recover the hidden third-dimension by use of multi-view image acquisition of the microscopic samples combined with pre/post-processing steps including sparse feature-based stereo rectification, nonlocal-based optical flow estimation for dense matching and finally depth estimation. Employing the proposed approach, three-dimensional (3D) reconstructions of highly complex microscopic samples were achieved to facilitate the interpretation of topology and geometry of surface/shape attributes of the samples. As a byproduct of the proposed approach, high-definition 3D printed models of the samples can be generated as a tangible means of physical understanding. Extensive comparisons with the state-of-the-art reveal the strength and superiority of the proposed method in uncovering the details of the highly complex microscopic samples.

  15. Optical Analysis of an Ultra-High resolution Two-Mirror Soft X-Ray Microscope

    NASA Technical Reports Server (NTRS)

    Shealy, David L.; Wang, Cheng; Hoover, Richard B.

    1994-01-01

    This work has summarized for a Schwarzschild microscope some relationships between numerical aperture (NA), magnification, diameter of the primary mirror, radius of curvature of the secondary mirror, and the total length of the microscope. To achieve resolutions better than a spherical Schwarzschild microscope of 3.3 Lambda for a perfectly aligned and fabricated system. it is necessary to use aspherical surfaces to control higher-order aberrations. For an NA of 0.35, the aspherical Head microscope provides diffraction limited resolution of 1.4 Lambda where the aspherical surfaces differ from the best fit spherical surface by approximately 1 micrometer. However, the angle of incidence varies significantly over the primary and the secondary mirrors, which will require graded multilayer coatings to operate near peak reflectivities. For higher numerical apertures, the variation of the angle of incidence over the secondary mirror surface becomes a serious problem which must be solved before multilayer coatings can be used for this application. Tolerance analysis of the spherical Schwarzschild microscope has shown that water window operations will require 2-3 times tighter tolerances to achieve a similar performance for operations with 130 A radiation. Surface contour errors have been shown to have a significant impact on the MTF and must be controlled to a peak-to-valley variation of 50-100 A and a frequency of 8 periods over the surface of a mirror.

  16. Microscopic optical model potential based on a Dirac Brueckner Hartree Fock approach and the relevant uncertainty analysis

    NASA Astrophysics Data System (ADS)

    Xu, Ruirui; Ma, Zhongyu; Muether, Herbert; van Dalen, E. N. E.; Liu, Tinjin; Zhang, Yue; Zhang, Zhi; Tian, Yuan

    2017-09-01

    A relativistic microscopic optical model potential, named CTOM, for nucleon-nucleus scattering is investigated in the framework of Dirac-Brueckner-Hartree-Fock approach. The microscopic feature of CTOM is guaranteed through rigorously adopting the isospin dependent DBHF calculation within the subtracted T matrix scheme. In order to verify its prediction power, a global study n, p+ A scattering are carried out. The predicted scattering observables coincide with experimental data within a good accuracy over a broad range of targets and a large region of energies only with two free items, namely the free-range factor t in the applied improved local density approximation and minor adjustments of the scalar and vector potentials in the low-density region. In addition, to estimate the uncertainty of the theoretical results, the deterministic simple least square approach is preliminarily employed to derive the covariance of predicted angular distributions, which is also briefly contained in this paper.

  17. Prevention of electron beam transmittance for biological cell imaging using electron beam excitation-assisted optical microscope

    NASA Astrophysics Data System (ADS)

    Fukuta, Masahiro; Nawa, Yasunori; Inami, Wataru; Kawata, Yoshimasa

    2016-12-01

    We demonstrated the high-spatial-resolution imaging of label-free biological cells using an electron beam excitation-assisted optical (EXA) microscope without irradiation damage by the electron beam. An EXA microscope can be used to observe a specimen with a nanometric light source excited in the Si3N4 membrane by an electron beam. The incident electron beam penetrates the Si3N4 membrane and damages the specimen. To suppress the irradiation damage of the specimen, we prevented the transmittance of the electron beam by coating the Si3N4 membrane with a gold thin film. To obtain an electron beam transmittance through the Si3N4 of 0%, a gold film of 15 nm thickness was required. By adding the gold layer, a label-free cellular structure was observed with 135-nm spatial resolution.

  18. Prevention of electron beam transmittance for biological cell imaging using electron beam excitation-assisted optical microscope

    NASA Astrophysics Data System (ADS)

    Fukuta, Masahiro; Nawa, Yasunori; Inami, Wataru; Kawata, Yoshimasa

    2017-04-01

    We demonstrated the high-spatial-resolution imaging of label-free biological cells using an electron beam excitation-assisted optical (EXA) microscope without irradiation damage by the electron beam. An EXA microscope can be used to observe a specimen with a nanometric light source excited in the Si3N4 membrane by an electron beam. The incident electron beam penetrates the Si3N4 membrane and damages the specimen. To suppress the irradiation damage of the specimen, we prevented the transmittance of the electron beam by coating the Si3N4 membrane with a gold thin film. To obtain an electron beam transmittance through the Si3N4 of 0%, a gold film of 15 nm thickness was required. By adding the gold layer, a label-free cellular structure was observed with 135-nm spatial resolution.

  19. Resolution of 90 nm (lambda/5) in an optical transmission microscope with an annular condenser.

    PubMed

    Vainrub, Arnold; Pustovyy, Oleg; Vodyanoy, Vitaly

    2006-10-01

    Resolution of 90 nm was achieved with a research microscope simply by replacing the standard bright-field condenser with a homebuilt illumination system with a cardioid annular condenser. Diffraction gratings with 100 nm width lines as well as less than 100 nm size features of different-shaped objects were clearly visible on a calibrated microscope test slide. The resolution increase results from a known narrower diffraction pattern in coherent illumination for the annular aperture compared with the circular aperture. This explanation is supported by an excellent accord of calculated and measured diffraction patterns for a 50 nm radius disk.

  20. Resolution of 90 nm (λ/5) in an optical transmission microscope with an annular condenser

    NASA Astrophysics Data System (ADS)

    Vainrub, Arnold; Pustovyy, Oleg; Vodyanoy, Vitaly

    2006-10-01

    Resolution of 90 nm was achieved with a research microscope simply by replacing the standard bright-field condenser with a homebuilt illumination system with a cardioid annular condenser. Diffraction gratings with 100 nm width lines as well as less than 100 nm size features of different-shaped objects were clearly visible on a calibrated microscope test slide. The resolution increase results from a known narrower diffraction pattern in coherent illumination for the annular aperture compared with the circular aperture. This explanation is supported by an excellent accord of calculated and measured diffraction patterns for a 50 nm radius disk.

  1. Dynamic nano-imaging of label-free living cells using electron beam excitation-assisted optical microscope

    NASA Astrophysics Data System (ADS)

    Fukuta, Masahiro; Kanamori, Satoshi; Furukawa, Taichi; Nawa, Yasunori; Inami, Wataru; Lin, Sheng; Kawata, Yoshimasa; Terakawa, Susumu

    2015-11-01

    Optical microscopes are effective tools for cellular function analysis because biological cells can be observed non-destructively and non-invasively in the living state in either water or atmosphere condition. Label-free optical imaging technique such as phase-contrast microscopy has been analysed many cellular functions, and it is essential technology for bioscience field. However, the diffraction limit of light makes it is difficult to image nano-structures in a label-free living cell, for example the endoplasmic reticulum, the Golgi body and the localization of proteins. Here we demonstrate the dynamic imaging of a label-free cell with high spatial resolution by using an electron beam excitation-assisted optical (EXA) microscope. We observed the dynamic movement of the nucleus and nano-scale granules in living cells with better than 100 nm spatial resolution and a signal-to-noise ratio (SNR) around 10. Our results contribute to the development of cellular function analysis and open up new bioscience applications.

  2. Chronic monitoring of cortical hemodynamics in behaving, freely-moving rats using a miniaturized head-mounted optical microscope

    NASA Astrophysics Data System (ADS)

    Sigal, Iliya; Gad, Raanan; Koletar, Margaret; Ringuette, Dene; Stefanovic, Bojana; Levi, Ofer

    2016-03-01

    Growing interest within the neurophysiology community in assessing healthy and pathological brain activity in animals that are awake and freely-behaving has triggered the need for optical systems that are suitable for such longitudinal studies. In this work we report label-free multi-modal imaging of cortical hemodynamics in the somatosensory cortex of awake, freely-behaving rats, using a novel head-mounted miniature optical microscope. The microscope employs vertical cavity surface emitting lasers (VCSELs) at three distinct wavelengths (680 nm, 795 nm, and 850 nm) to provide measurements of four hemodynamic markers: blood flow speeds, HbO, HbR, and total Hb concentration, across a > 2 mm field of view. Blood flow speeds are extracted using Laser Speckle Contrast Imaging (LSCI), while oxygenation measurements are performed using Intrinsic Optical Signal Imaging (IOSI). Longitudinal measurements on the same animal are made possible over the course of > 6 weeks using a chronic window that is surgically implanted into the skull. We use the device to examine changes in blood flow and blood oxygenation in superficial cortical blood vessels and tissue in response to drug-induced absence-like seizures, correlating motor behavior with changes in blood flow and blood oxygenation in the brain.

  3. Dynamic nano-imaging of label-free living cells using electron beam excitation-assisted optical microscope

    PubMed Central

    Fukuta, Masahiro; Kanamori, Satoshi; Furukawa, Taichi; Nawa, Yasunori; Inami, Wataru; Lin, Sheng; Kawata, Yoshimasa; Terakawa, Susumu

    2015-01-01

    Optical microscopes are effective tools for cellular function analysis because biological cells can be observed non-destructively and non-invasively in the living state in either water or atmosphere condition. Label-free optical imaging technique such as phase-contrast microscopy has been analysed many cellular functions, and it is essential technology for bioscience field. However, the diffraction limit of light makes it is difficult to image nano-structures in a label-free living cell, for example the endoplasmic reticulum, the Golgi body and the localization of proteins. Here we demonstrate the dynamic imaging of a label-free cell with high spatial resolution by using an electron beam excitation-assisted optical (EXA) microscope. We observed the dynamic movement of the nucleus and nano-scale granules in living cells with better than 100 nm spatial resolution and a signal-to-noise ratio (SNR) around 10. Our results contribute to the development of cellular function analysis and open up new bioscience applications. PMID:26525841

  4. Improvement of tapping-mode scanning near-field optical microscope

    NASA Astrophysics Data System (ADS)

    Zhuo, Wenjiang; Li, Qin; Sun, Jialin; Xu, Jianhua; Zhao, Jun; Guo, Jihua

    2000-10-01

    The commercial crystal tuning fork glued with an optical fiber probe is used as the sensitive detecting element for the tapping-mode scanning near-field optical microscopy. Firstly, the single-mode optical fiber is etched down to a small diameter to decrease the burden of the tuning fork. Secondary, the fiber is etched for the second time to form the sharp tip with large cone angle. Thirdly, the fiber probe, with nanometric tip and high light throughput, is glued to tuning fork by Cyanoacrylate Adhesive. The measured quality factor, Q, of the tuning fork/optical fiber probe assembly prepared in this way is higher than 300. The optical signal is modulated to the frequency of the tuning fork by optical fiber probe as it is detecting the topography of sample. The high-resolution of the tapping- mode detector is proved by imaging the topography of the grating and biological cell.

  5. Optical Inverted Microscope Imaging System for Biological and Non-Biological Samples

    DTIC Science & Technology

    2009-02-11

    Leica 6000 Microscope. Publications: 1. Gupta, M. K., Khokhar , S. K., Phillips, D. M., Caserta, T. M., Sowards, L. A. Drummy, L F., Kadakia, M. P...Naik, R. R. (2007) Patterned Silk Films Cast from Ionic Liquid Solubilized Fibroin as Scaffolds for Cell Growth. Langmuir 23,1315-1319. 2. Khokhar

  6. Laboratory-size three-dimensional water-window x-ray microscope with Wolter type I mirror optics

    SciTech Connect

    Ohsuka, Shinji; Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro; Nakano, Tomoyasu; Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao

    2016-01-28

    We constructed a laboratory-size three-dimensional water-window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques. It consists of an electron-impact x-ray source emitting oxygen Kα x-rays, Wolter type I grazing incidence mirror optics, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit better than 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm-scale three-dimensional fine structures were resolved.

  7. Use of scanning near-field optical microscope with an aperture probe for detection of luminescent nanodiamonds

    NASA Astrophysics Data System (ADS)

    Shershulin, V. A.; Samoylenko, S. R.; Shenderova, O. A.; Konov, V. I.; Vlasov, I. I.

    2017-02-01

    The suitability of scanning near-field optical microscopy (SNOM) to image photoluminescent diamond nanoparticles with nanoscale resolution is demonstrated. Isolated diamond nanocrystals with an average size of 100 nm, containing negatively charged nitrogen-vacancy (NV-) centers, were chosen as tested material. The NV- luminescence was stimulated by continuous 532 nm laser light. Sizes of analyzed crystallites were monitored by an atomic force microscope. The lateral resolution of the order of 100 nm was reached in SNOM imaging of diamond nanoparticles using 150 nm square aperture of the probe.

  8. Laboratory-size three-dimensional water-window x-ray microscope with Wolter type I mirror optics

    NASA Astrophysics Data System (ADS)

    Ohsuka, Shinji; Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro; Nakano, Tomoyasu; Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao

    2016-01-01

    We constructed a laboratory-size three-dimensional water-window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques. It consists of an electron-impact x-ray source emitting oxygen Kα x-rays, Wolter type I grazing incidence mirror optics, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit better than 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm-scale three-dimensional fine structures were resolved.

  9. Hollow-pyramid based scanning near-field optical microscope coupled to femtosecond pulses: a tool for nonlinear optics at the nanoscale.

    PubMed

    Celebrano, Michele; Biagioni, Paolo; Zavelani-Rossi, Margherita; Polli, Dario; Labardi, Massimiliano; Allegrini, Maria; Finazzi, Marco; Duò, Lamberto; Cerullo, Giulio

    2009-03-01

    We describe an aperture scanning near-field optical microscope (SNOM) using cantilevered hollow pyramid probes coupled to femtosecond laser pulses. Such probes, with respect to tapered optical fibers, present higher throughput and laser power damage threshold, as well as greater mechanical robustness. In addition, they preserve pulse duration and polarization in the near field. The instrument can operate in two configurations: illumination mode, in which the SNOM probe is used to excite the nonlinear response in the near field, and collection mode, where it collects the nonlinear emission following far-field excitation. We present application examples highlighting the capability of the system to observe the nonlinear optical response of nanostructured metal surfaces (gold projection patterns and gold nanorods) with sub-100-nm spatial resolution.

  10. Twelfth degree spline with application to quadrature.

    PubMed

    Mohammed, P O; Hamasalh, F K

    2016-01-01

    In this paper existence and uniqueness of twelfth degree spline is proved with application to quadrature. This formula is in the class of splines of degree 12 and continuity order [Formula: see text] that matches the derivatives up to order 6 at the knots of a uniform partition. Some mistakes in the literature are pointed out and corrected. Numerical examples are given to illustrate the applicability and efficiency of the new method.

  11. Numerical quadratures for approximate computation of ERBS

    NASA Astrophysics Data System (ADS)

    Zanaty, Peter

    2013-12-01

    In the ground-laying paper [3] on expo-rational B-splines (ERBS), the default numerical method for approximate computation of the integral with C∞-smooth integrand in the definition of ERBS is Romberg integration. In the present work, a variety of alternative numerical quadrature methods for computation of ERBS and other integrals with smooth integrands are studied, and their performance is compared on several benchmark examples.

  12. Density dependence of microscopic nucleon optical potential in first order Brueckner theory

    NASA Astrophysics Data System (ADS)

    Saliem, S. M.; Haider, W.

    2002-06-01

    In the present work we apply the lowest order Brueckner theory of infinite nuclear matter to obtain nucleon-nucleus optical potential for p-40Ca elastic scattering at 200 MeV using Urbana V14 soft core internucleon potential. We have investigated the effect of target density on the calculated nucleon-nucleus optical potential. We find that the calculated optical potentials depend quite sensitively on the density distribution of the target nucleus. The important feature is that the real part of calculated central optical potential for all densities shows a wine-bottle-bottom type behaviour at this energy. We also discuss the effect of our new radial dependent effective mass correction. Finally, we compare the prediction of our calculated nucleon optical potential using V14 with the prediction using older hard core Hamada-Johnston internucleon potential for p-40Ca elastic scattering at 200 MeV.

  13. A novel optical microscope for imaging large embryos and tissue volumes with sub-cellular resolution throughout

    PubMed Central

    McConnell, Gail; Trägårdh, Johanna; Amor, Rumelo; Dempster, John; Reid, Es; Amos, William Bradshaw

    2016-01-01

    Current optical microscope objectives of low magnification have low numerical aperture and therefore have too little depth resolution and discrimination to perform well in confocal and nonlinear microscopy. This is a serious limitation in important areas, including the phenotypic screening of human genes in transgenic mice by study of embryos undergoing advanced organogenesis. We have built an optical lens system for 3D imaging of objects up to 6 mm wide and 3 mm thick with depth resolution of only a few microns instead of the tens of microns currently attained, allowing sub-cellular detail to be resolved throughout the volume. We present this lens, called the Mesolens, with performance data and images from biological specimens including confocal images of whole fixed and intact fluorescently-stained 12.5-day old mouse embryos. DOI: http://dx.doi.org/10.7554/eLife.18659.001 PMID:27661778

  14. Comparison of two Galerkin quadrature methods

    SciTech Connect

    Morel, J. E.; Warsa, J. S.; Franke, B. C.; Prinja, A. K.

    2013-07-01

    We compare two methods for generating Galerkin quadrature for problems with highly forward-peaked scattering. In Method 1, the standard Sn method is used to generate the moment-to-discrete matrix and the discrete-to-moment is generated by inverting the moment-to-discrete matrix. In Method 2, which we introduce here, the standard Sn method is used to generate the discrete-to-moment matrix and the moment-to-discrete matrix is generated by inverting the discrete-to-moment matrix. Method 1 has the advantage that it preserves both N eigenvalues and N eigenvectors (in a pointwise sense) of the scattering operator with an N-point quadrature. Method 2 has the advantage that it generates consistent angular moment equations from the corresponding S{sub N} equations while preserving N eigenvalues of the scattering operator with an N-point quadrature. Our computational results indicate that these two methods are quite comparable for the test problem considered. (authors)

  15. Three-dimensional force microscope: A nanometric optical tracking and magnetic manipulation system for the biomedical sciences

    NASA Astrophysics Data System (ADS)

    Fisher, J. K.; Cummings, J. R.; Desai, K. V.; Vicci, L.; Wilde, B.; Keller, K.; Weigle, C.; Bishop, G.; Taylor, R. M.; Davis, C. W.; Boucher, R. C.; O'Brien, E. Timothy; Superfine, R.

    2005-05-01

    We report here the development of a three-dimensional (3D) magnetic force microscope for applying forces to and measuring responses of biological systems and materials. This instrument combines a conventional optical microscope with a free-floating or specifically bound magnetic bead used as a mechanical probe. Forces can be applied by the bead to microscopic structures of interest (specimens), while the reaction displacement of the bead is measured. This enables 3D mechanical manipulations and measurements to be performed on specimens in fluids. Force is generated by the magnetically permeable bead in reaction to fields produced by external electromagnets. The displacement is measured by interferometry using forward light scattered by the bead from a focused laser beam. The far-field interference pattern is imaged on a quadrant photodetector from which the 3D displacement can be computed over a limited range about the focal point. The bead and specimen are mounted on a 3D translation stage and feedback techniques are used to keep the bead within this limited range. We demonstrate the system with application to beads attached to cilia in human lung cell cultures.

  16. Nanocluster: photothermal bubble as optical probes for cytometric and microscopic applications

    NASA Astrophysics Data System (ADS)

    Lapotko, Dmitri O.; Lukianova-Hleb, Ekaterina Y.; Hafner, Jason H.

    2007-06-01

    The ability to detect optical signals form a cellular target depends upon the amount of optical energy that can be generated by this target as the signal. Given that the sensitivity of optical detectors has some finite limit, further increase of the sensitivity of optical diagnostic methods requires increasing the energy of target-generated signal. Usually this energy is converted by the cellular target upon its optical excitation and is limited by many factors such as: cell and target damage thresholds, efficiency of excitation energy conversion, size of the target etc. All these put principal limitation on sensing small targets (like molecules) in living cells with any optical method because the energy that can be safely converted by the target into a signal is limited. To overcome this limitation and to improve the sensitivity of optical microscopy of living cells (and cytometry in general) we propose the concept of intracellular amplification of the optical signal. This concept includes two major steps. First, primary (pump) optical radiation interacts with the target (a probe molecule) to generate a transient target. Second, the transient target is sensed with additional optical radiation that does not interact strongly with primary target or the cell, and, hence, may have high enough energy to increase the signal from transient target even above the energy of pump radiation, which is limited by cell and target damage thresholds. We propose to use optical scattering from clusters of gold nanoparticles (the target) that are selectively formed in specific cells through antibody-receptor interaction and through endocytosis. To amplify this optical signal we propose to generate photothermal bubbles (the transient target) around those clusters. In experiments with water suspensions and with individual tumor K562 cells we have achieved optical signal amplification in individual cells (relatively to the scattering signal from intact cells): with gold nanorod

  17. Theoretical and Experimental Studies of the Electro-Optic Effect: Toward a Microscopic Understanding.

    DTIC Science & Technology

    1981-08-01

    The electro - optic effect is investigated both theoretically and experimentally. The theoretical approach is based upon W.A. Harrison’s ’Bond-Orbital...Model’. The separate electronic and lattice contributions to the second-order, electro - optic susceptibility are examined within the context of this...frequency (dc) electric field is outlined. Finally, experimental measurements of the electro - optic effects in TeO2 and tl3AsAs3 have been performed and the results of these measurements are presented. (Author)

  18. Experimental generation of broadband quadrature entanglement using laser pulses

    SciTech Connect

    Zhang, Yun; Furuta, Tatsuya; Okubo, Ryuhi; Takahashi, Kosuke; Hirano, Takuya

    2007-07-15

    We report on the generation of broadband pulsed quadrature entanglement by combining two squeezed vacua, which are generated from two degenerate optical parametric amplifiers (OPAs), on a beam splitter. With a single pass through OPA, in which a periodically poled lithium niobate waveguide is used as a nonlinear material, the noise reduction of 3.4{+-}0.2 dB below the shot noise limit is observed with a bandwidth of more than 200 MHz. The entanglement correlation or EPR correlation is confirmed with a sufficient criterion <{delta}{sup 2}(X{sub a}+X{sub b})>+<{delta}{sup 2}(Y{sub a}-Y{sub b})>=1.28<2.

  19. Optical monitoring of neuronal activity at high frame rate with a digital random-access multiphoton (RAMP) microscope.

    PubMed

    Otsu, Yo; Bormuth, Volker; Wong, Jerome; Mathieu, Benjamin; Dugué, Guillaume P; Feltz, Anne; Dieudonné, Stéphane

    2008-08-30

    Two-photon microscopy offers the promise of monitoring brain activity at multiple locations within intact tissue. However, serial sampling of voxels has been difficult to reconcile with millisecond timescales characteristic of neuronal activity. This is due to the conflicting constraints of scanning speed and signal amplitude. The recent use of acousto-optic deflector scanning to implement random-access multiphoton microscopy (RAMP) potentially allows to preserve long illumination dwell times while sampling multiple points-of-interest at high rates. However, the real-life abilities of RAMP microscopy regarding sensitivity and phototoxicity issues, which have so far impeded prolonged optical recordings at high frame rates, have not been assessed. Here, we describe the design, implementation and characterisation of an optimised RAMP microscope. We demonstrate the application of the microscope by monitoring calcium transients in Purkinje cells and cortical pyramidal cell dendrites and spines. We quantify the illumination constraints imposed by phototoxicity and show that stable continuous high-rate recordings can be obtained. During these recordings the fluorescence signal is large enough to detect spikes with a temporal resolution limited only by the calcium dye dynamics, improving upon previous techniques by at least an order of magnitude.

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

    PubMed Central

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

    2015-01-01

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

  1. Low noise optical lattices for a Li-6 Fermi gas microscope

    NASA Astrophysics Data System (ADS)

    Mazurenko, Anton; Parsons, Maxwell; Chiu, Christie; Huber, Florian; Blatt, Sebastian; Greiner, Markus

    2015-05-01

    We report on recent progress towards single-site resolved imaging of fermions in an optical lattice. Fermionic 6-Li atoms are trapped in an optical lattice 10 μm below a high-quality reference surface in the image plane of a high resolution (NA 0.85) imaging system. We have created a highly intensity-stable optical lattice whose depth remains adjustable over three orders of magnitude. The high optical resolution enables a band mapping technique that allows detection of less than 1000 atoms in the ground band of the lattice. We use this technique to measure the decay of the radial ground band population and find lifetimes up to 70 seconds, limited by spontaneous scattering of lattice light. ARO DARPA OLE, ARO MURI, NSF, AFOSR MURI, and The Moore Foundation.

  2. 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.

  3. Imaging of InGaN inhomogeneities using visible aperturelessnear-field scanning optical microscope

    SciTech Connect

    Stebounova, Larissa V.; Romanyuk, Yaroslav E.; Chen, Dongxue; Leone, Stephen R.

    2007-06-14

    The optical properties of epitaxially grown islands of InGaN are investigated with nanometer-scale spatial resolution using visible apertureless near-field scanning optical microscopy. Scattered light from the tip-sample system is modulated by cantilever oscillations and detected at the third harmonic of the oscillation frequency to distinguish the near-field signal from unwanted scattered background light. Scattered near-field measurements indicate that the as-grown InGaN islanded film may exhibit both inhomogeneous In composition and strain-induced changes that affect the optical signal at 633 nm and 532 nm. Changes are observed in the optical contrast for large 3D InGaN islands (100's of nm) of the same height. Near-field optical mapping of small grains on a finer scale reveals InGaN composition or strain-induced irregularities in features with heights of only 2 nm, which exhibit different near-field signals at 633 nm and 532 nm incident wavelengths. Optical signal contrast from topographic features as small as 30 nm is detected.

  4. Microscopic validation of macroscopic in vivo images enabled by same-slide optical and nuclear fusion.

    PubMed

    Inoue, Kazumasa; Gibbs, Summer L; Liu, Fangbing; Lee, Jeong Heon; Xie, Yang; Ashitate, Yoshitomo; Fujii, Hirofumi; Frangioni, John V; Choi, Hak Soo

    2014-11-01

    It is currently difficult to determine the molecular and cellular basis for radioscintigraphic signals obtained during macroscopic in vivo imaging. The field is in need of technology that helps bridge the macroscopic and microscopic regimes. To solve this problem, we developed a fiducial marker (FM) simultaneously compatible with 2-color near-infrared (NIR) fluorescence (700 and 800 nm), autoradiography, and conventional hematoxylin-eosin (HE) histology. The FM was constructed from an optimized concentration of commercially available human serum albumin, 700- and 800-nm NIR fluorophores, (99m)Tc-pertechnetate, dimethyl sulfoxide, and glutaraldehyde. Lymphangioleiomyomatosis cells coexpressing the sodium iodide symporter and green fluorescent protein were labeled with 700-nm fluorophore and (99m)Tc-pertechnatate and then administered intratracheally into CD-1 mice. After in vivo SPECT imaging and ex vivo SPECT and NIR fluorescence imaging of the lungs, 30-μm frozen sections were prepared and processed for 800-nm NIR fluorophore costaining, autoradiography, and HE staining on the same slide using the FMs to coregister all datasets. Optimized FMs, composed of 100 μM unlabeled human serum albumin, 1 μM NIR fluorescent human serum albumin, 15% dimethyl sulfoxide, and 3% glutaraldehyde in phosphate-buffered saline (pH 7.4), were prepared within 15 min, displayed homogeneity and stability, and were visible by all imaging modalities, including HE staining. Using these FMs, tissue displaying high signal by SPECT could be dissected and analyzed on the same slide and at the microscopic level for 700-nm NIR fluorescence, 800-nm NIR fluorescence, autoradiography, and HE histopathologic staining. When multimodal FMs are combined with a new technique for simultaneous same-slide NIR fluorescence imaging, autoradiography, and HE staining, macroscopic in vivo images can now be studied unambiguously at the microscopic level. © 2014 by the Society of Nuclear Medicine and Molecular

  5. Imaging optical fields below metal films and metal-dielectric waveguides by a scanning microscope

    NASA Astrophysics Data System (ADS)

    Zhu, Liangfu; Wang, Yong; Zhang, Douguo; Wang, Ruxue; Qiu, Dong; Wang, Pei; Ming, Hai; Badugu, Ramachandram; Rosenfeld, Mary; Lakowicz, Joseph R.

    2017-09-01

    Laser scanning confocal fluorescence microscopy (LSCM) is now an important method for tissue and cell imaging when the samples are located on the surfaces of glass slides. In the past decade, there has been extensive development of nano-optical structures that display unique effects on incident and transmitted light, which will be used with novel configurations for medical and consumer products. For these applications, it is necessary to characterize the light distribution within short distances from the structures for efficient detection and elimination of bulky optical components. These devices will minimize or possibly eliminate the need for free-space light propagation outside of the device itself. We describe the use of the scanning function of a LSCM to obtain 3D images of the light intensities below the surface of nano-optical structures. More specifically, we image the spatial distributions inside the substrate of fluorescence emission coupled to waveguide modes after it leaks through thin metal films or dielectric-coated metal films. The observed spatial distribution were in general agreement with far-field calculations, but the scanning images also revealed light intensities at angles not observed with classical back focal plane imaging. Knowledge of the subsurface optical intensities will be crucial in the combination of nano-optical structures with rapidly evolving imaging detectors.

  6. Microscopic thin film optical anisotropy imaging at the solid-liquid interface.

    PubMed

    Miranda, Adelaide; De Beule, Pieter A A

    2016-04-01

    Optical anisotropy of thin films has been widely investigated through ellipsometry, whereby typically an optical signal is averaged over a ∼1 cm(2) elliptical area that extends with increasing angle-of-incidence (AOI). Here, we report on spectroscopic imaging ellipsometry at the solid-liquid interface applied to a supported lipid bilayer (SLB). We detail how a differential spectrally resolved ellipsometry measurement, between samples with and without optically anisotropic thin film on an absorbing substrate, can be applied to recover in and out of plane refractive indices of the thin film with known film thickness, hence determining the thin film optical anisotropy. We also present how optimal wavelength and AOI settings can be determined ensuring low parameter cross correlation between the refractive indices to be determined from a differential measurement in Δ ellipsometry angle. Furthermore, we detail a Monte Carlo type analysis that allows one to determine the minimal required optical ellipsometry resolution to recover a given thin film anisotropy. We conclude by presenting a new setup for a spectroscopic imaging ellipsometry based on fiber supercontinuum laser technology, multi-wavelength diode system, and an improved liquid cell design, delivering a 5 ×-10 × ellipsometric noise reduction over state-of-the-art. We attribute this improvement to increased ellipsometer illumination power and a reduced light path in liquid through the use of a water dipping objective.

  7. Microscopic thin film optical anisotropy imaging at the solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Miranda, Adelaide; De Beule, Pieter A. A.

    2016-04-01

    Optical anisotropy of thin films has been widely investigated through ellipsometry, whereby typically an optical signal is averaged over a ˜1 cm2 elliptical area that extends with increasing angle-of-incidence (AOI). Here, we report on spectroscopic imaging ellipsometry at the solid-liquid interface applied to a supported lipid bilayer (SLB). We detail how a differential spectrally resolved ellipsometry measurement, between samples with and without optically anisotropic thin film on an absorbing substrate, can be applied to recover in and out of plane refractive indices of the thin film with known film thickness, hence determining the thin film optical anisotropy. We also present how optimal wavelength and AOI settings can be determined ensuring low parameter cross correlation between the refractive indices to be determined from a differential measurement in Δ ellipsometry angle. Furthermore, we detail a Monte Carlo type analysis that allows one to determine the minimal required optical ellipsometry resolution to recover a given thin film anisotropy. We conclude by presenting a new setup for a spectroscopic imaging ellipsometry based on fiber supercontinuum laser technology, multi-wavelength diode system, and an improved liquid cell design, delivering a 5 ×-10 × ellipsometric noise reduction over state-of-the-art. We attribute this improvement to increased ellipsometer illumination power and a reduced light path in liquid through the use of a water dipping objective.

  8. Multiple-order imaging for optical critical dimension metrology using microscope characterization

    NASA Astrophysics Data System (ADS)

    Qin, Jing; Zhou, Hui; Barnes, Bryan M.; Goasmat, Francois; Dixson, Ronald; Silver, Richard M.

    2012-10-01

    There has been much recent work in developing advanced optical metrology applications that use imaging optics for optical critical dimension (OCD) measurements, defect detection, and for potential use with in-die metrology applications. We have previously reported quantitative measurements for sub-50 nm CD dense arrays which scatter only the 0th-order specular diffraction component using angle-resolved scatterfield microscopy. Through angle-resolved and focus-resolved imaging, we now measure OCD targets with three-dimensional scattered fields that contain multiple Fourier frequencies. Experimental sensitivity to nanometer scale linewidth changes is presented, supported by simulation studies. A new, more advanced approach to tool normalization is coupled with rigorous electromagnetic simulations and library based regression fitting that potentially enables OCD measurements with sub-nanometer uncertainties for targets that scatter multiple Fourier frequencies.

  9. Single-spin microscope with sub-nanoscale resolution based on optically detected magnetic resonance

    SciTech Connect

    Berman, Gennady P; Chernobrod, Boris

    2009-01-01

    Invention of scanning tunneling microscope (STM) and atomic force microscope (AFM) initiated a new era of material science and technology characterized by 2-D imaging with atomic resolution and manipulation of individual atoms. However, for further progress in material science, and in particular in structural biology, 3-D imaging with sub-nanometer resolution is very desirable. Currently the most promising technique for 3-D imaging is magnetic resonance force microscopy (MRFM), which senses individual electron spins [1,2] with nanoscale resolution and can detect collective magnetization of about 100 nuclear spins [3]. The highest sensitivity demonstrated by MRFM is based on a time modulation technique called the oscillating cantilever-driven adiabatic reversals (OSCAAR) which requires a long phase relaxation time T 2 of measured spins, which usually corresponds to rather low temperature. For example, a temperature of 300 mK was used in the case of 3D imaging of the tobacco mosaic virus [3]. This limitation is incompatible with the room-temperature operation needed for the study of biological systems under physiological conditions.

  10. Spatially resolved quantum nano-optics of single photons using an electron microscope.

    PubMed

    Tizei, L H G; Kociak, M

    2013-04-12

    We report on the experimental demonstration of single-photon state generation and characterization in an electron microscope. In this aim we have used low intensity relativistic (energy between 60 and 100 keV) electrons beams focused in a ca. 1 nm probe to excite diamond nanoparticles. This triggered individual neutral nitrogen-vacancy centers to emit photons which could be gathered and sent to a Hanbury Brown-Twiss intensity interferometer. The detection of a dip in the correlation function at small time delays clearly demonstrates antibunching and thus the creation of nonclassical light states. Specifically, we have also demonstrated single-photon states detection. We unveil the mechanism behind quantum states generation in an electron microscope, and show that it clearly makes cathodoluminescence the nanometer scale analog of photoluminescence. By using an extremely small electron probe size and the ability to monitor its position with subnanometer resolution, we also show the possibility of measuring the quantum character of the emitted beam with deep subwavelength resolution.

  11. Development of the water window imaging X-ray microscope utilizing normal-incidence multilayer optics

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Shealy, David L.; Brinkley, B. R.; Baker, Phillip C.; Barbee, Troy W., Jr.; Walker, Arthur B. C., Jr.

    1991-01-01

    A water-window imaging X-ray telescope configured with normal-incidence multilayer X-ray mirrors has been developed to obtain images with unprecedented spatial resolution and contrast of carbon-based microstructures within living cells. The narrow bandpass response inherent in multilayer X-ray optics is accurately tuned to wavelengths within the water window.

  12. Optical and Optoelectronic Property Analysis of Nanomaterials inside Transmission Electron Microscope.

    PubMed

    Fernando, Joseph F S; Zhang, Chao; Firestein, Konstantin L; Golberg, Dmitri

    2017-09-13

    In situ transmission electron microscopy (TEM) allows one to investigate nanostructures at high spatial resolution in response to external stimuli, such as heat, electrical current, mechanical force and light. This review exclusively focuses on the optical, optoelectronic and photocatalytic studies inside TEM. With the development of TEMs and specialized TEM holders that include in situ illumination and light collection optics, it is possible to perform optical spectroscopies and diverse optoelectronic experiments inside TEM with simultaneous high resolution imaging of nanostructures. Optical TEM holders combining the capability of a scanning tunneling microscopy probe have enabled nanomaterial bending/stretching and electrical measurements in tandem with illumination. Hence, deep insights into the optoelectronic property versus true structure and its dynamics could be established at the nanometer-range precision thus evaluating the suitability of a nanostructure for advanced light driven technologies. This report highlights systems for in situ illumination of TEM samples and recent research work based on the relevant methods, including nanomaterial cathodoluminescence, photoluminescence, photocatalysis, photodeposition, photoconductivity and piezophototronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Wave optics theory and 3-D deconvolution for the light field microscope.

    PubMed

    Broxton, Michael; Grosenick, Logan; Yang, Samuel; Cohen, Noy; Andalman, Aaron; Deisseroth, Karl; Levoy, Marc

    2013-10-21

    Light field microscopy is a new technique for high-speed volumetric imaging of weakly scattering or fluorescent specimens. It employs an array of microlenses to trade off spatial resolution against angular resolution, thereby allowing a 4-D light field to be captured using a single photographic exposure without the need for scanning. The recorded light field can then be used to computationally reconstruct a full volume. In this paper, we present an optical model for light field microscopy based on wave optics, instead of previously reported ray optics models. We also present a 3-D deconvolution method for light field microscopy that is able to reconstruct volumes at higher spatial resolution, and with better optical sectioning, than previously reported. To accomplish this, we take advantage of the dense spatio-angular sampling provided by a microlens array at axial positions away from the native object plane. This dense sampling permits us to decode aliasing present in the light field to reconstruct high-frequency information. We formulate our method as an inverse problem for reconstructing the 3-D volume, which we solve using a GPU-accelerated iterative algorithm. Theoretical limits on the depth-dependent lateral resolution of the reconstructed volumes are derived. We show that these limits are in good agreement with experimental results on a standard USAF 1951 resolution target. Finally, we present 3-D reconstructions of pollen grains that demonstrate the improvements in fidelity made possible by our method.

  14. Wave optics theory and 3-D deconvolution for the light field microscope

    PubMed Central

    Broxton, Michael; Grosenick, Logan; Yang, Samuel; Cohen, Noy; Andalman, Aaron; Deisseroth, Karl; Levoy, Marc

    2013-01-01

    Light field microscopy is a new technique for high-speed volumetric imaging of weakly scattering or fluorescent specimens. It employs an array of microlenses to trade off spatial resolution against angular resolution, thereby allowing a 4-D light field to be captured using a single photographic exposure without the need for scanning. The recorded light field can then be used to computationally reconstruct a full volume. In this paper, we present an optical model for light field microscopy based on wave optics, instead of previously reported ray optics models. We also present a 3-D deconvolution method for light field microscopy that is able to reconstruct volumes at higher spatial resolution, and with better optical sectioning, than previously reported. To accomplish this, we take advantage of the dense spatio-angular sampling provided by a microlens array at axial positions away from the native object plane. This dense sampling permits us to decode aliasing present in the light field to reconstruct high-frequency information. We formulate our method as an inverse problem for reconstructing the 3-D volume, which we solve using a GPU-accelerated iterative algorithm. Theoretical limits on the depth-dependent lateral resolution of the reconstructed volumes are derived. We show that these limits are in good agreement with experimental results on a standard USAF 1951 resolution target. Finally, we present 3-D reconstructions of pollen grains that demonstrate the improvements in fidelity made possible by our method. PMID:24150383

  15. Development of the water window imaging X-ray microscope utilizing normal-incidence multilayer optics

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Shealy, David L.; Brinkley, B. R.; Baker, Phillip C.; Barbee, Troy W., Jr.; Walker, Arthur B. C., Jr.

    1991-01-01

    A water-window imaging X-ray telescope configured with normal-incidence multilayer X-ray mirrors has been developed to obtain images with unprecedented spatial resolution and contrast of carbon-based microstructures within living cells. The narrow bandpass response inherent in multilayer X-ray optics is accurately tuned to wavelengths within the water window.

  16. Microscopic [ital T]-Violating Optical Potential: Implications for Neutron-Transmission Experiments

    SciTech Connect

    Engel, J.; Gould, C.R.; Hnizdo, V. Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 Department of Physics and Schonland Research Centre for Nuclear Sciences, University of the Witwatersrand, Johannesburg, 2050 )

    1994-12-26

    We derive a [ital T]-violating [ital P]-conserving optical potential for neutron-nucleus scattering, starting from a uniquely determined two-body [rho]-exchange interaction with the same symmetry. We then obtain limits on the [ital T]-violating [rho]-nucleon coupling [ital [bar g

  17. Effect of cantilever geometry on the optical lever sensitivities and thermal noise method of the atomic force microscope

    SciTech Connect

    Sader, John E.; Lu, Jianing; Mulvaney, Paul

    2014-11-15

    Calibration of the optical lever sensitivities of atomic force microscope (AFM) cantilevers is especially important for determining the force in AFM measurements. These sensitivities depend critically on the cantilever mode used and are known to differ for static and dynamic measurements. Here, we calculate the ratio of the dynamic and static sensitivities for several common AFM cantilevers, whose shapes vary considerably, and experimentally verify these results. The dynamic-to-static optical lever sensitivity ratio is found to range from 1.09 to 1.41 for the cantilevers studied – in stark contrast to the constant value of 1.09 used widely in current calibration studies. This analysis shows that accuracy of the thermal noise method for the static spring constant is strongly dependent on cantilever geometry – neglect of these dynamic-to-static factors can induce errors exceeding 100%. We also discuss a simple experimental approach to non-invasively and simultaneously determine the dynamic and static spring constants and optical lever sensitivities of cantilevers of arbitrary shape, which is applicable to all AFM platforms that have the thermal noise method for spring constant calibration.

  18. Free radical erythrocyte damage in tumoral disease assessed by He-Ne laser and optical microscope through "Heinz Bodies" method.

    PubMed

    Broccio, M; Della Rovere, F; Granata, A; Wanderlingh, U; Zirilli, A; Tanzariello, A; Pirrone, G; Broccio, G

    1998-01-01

    Results obtained from blood sample readings by optical microscopy and He-Ne laser (lambda = 630.1 mW), have confirmed the reduction in Heinz Bodies (HB) formation time and the Transmittance Reduction Degree (TRD), in malignancies. The results of spectrometric readings in colorectum polyposis, (TRD = 0.07) and fibrocystic mastopathy (TRD = 0.08) gave results overlapping with controls (TRD = 0.08). In neoplasias, the early HB formation in erythrocytes observed by optical microscope corresponded to TRD increase = 0.17 (P < 0.01). TRD increase was statistically significant (P < 0.01), as well as the reduction in the time of HB appearance (< 0.01). The relationship between optical and laser readings was exponential in tumors, while it was linear in controls, in polyposis and mastopathies. The values of the correlation coefficients obtained by both methods were significant (P < 0.01) for all the studied groups. Moreover, these research data further support the existence, even in the earlier stages of the disease, of the labile state of the red cell membrane due to strong lipid peroxidation by FRs.

  19. Fabrication of bright and thin Zn₂SiO₄ luminescent film for electron beam excitation-assisted optical microscope.

    PubMed

    Furukawa, Taichi; Kanamori, Satoshi; Fukuta, Masahiro; Nawa, Yasunori; Kominami, Hiroko; Nakanishi, Yoichiro; Sugita, Atsushi; Inami, Wataru; Kawata, Yoshimasa

    2015-07-13

    We fabricated a bright and thin Zn₂SiO₄ luminescent film to serve as a nanometric light source for high-spatial-resolution optical microscopy based on electron beam excitation. The Zn₂SiO₄ luminescent thin film was fabricated by annealing a ZnO film on a Si₃N₄ substrate at 1000 °C in N₂. The annealed film emitted bright cathodoluminescence compared with the as-deposited film. The film is promising for nano-imaging with electron beam excitation-assisted optical microscopy. We evaluated the spatial resolution of a microscope developed using this Zn₂SiO₄ luminescent thin film. This is the first report of the investigation and application of ZnO/Si₃N₄ annealed at a high temperature (1000 °C). The fabricated Zn₂SiO₄ film is expected to enable high-frame-rate dynamic observation with ultra-high resolution using our electron beam excitation-assisted optical microscopy.

  20. 7D-folding integral in a density-dependent microscopic optical model potential for nucleon-nucleus scattering

    SciTech Connect

    Arellano, H. F.

    2011-09-15

    Microscopic optical model potentials, based on density-dependent effective interactions, involve multidimensional integrals to account for the full Fermi motion of the target struck nucleon throughout the nucleus. If a spherical matter distribution is assumed, then each matrix element of the optical potential requires the evaluation of seven-dimensional integrals. In this work we provide a full account of these integrals, retaining the genuine off-shell structure of the nucleon-nucleon effective interaction. The evaluation is based on the asymptotic separation of the optical model potential for nucleon-nucleus scattering in momentum space, where the potential is split into a free t-matrix contribution and another which depends exclusively on the gradient of the density-dependent g matrix. The calculated potentials, based on the Paris nucleon-nucleon (NN) potential, are applied to proton elastic scattering from {sup 16}O and {sup 90}Zr at beam energies between 30 and 65 MeV. The results were compared with two approximations to the unabridged expression, revealing moderate differences among their scattering observables. When comparing with results based on the Argonne v{sub 18} NNpotential, these differences appear smaller than those attainable by the choice of the internucleon potential.

  1. Effect of cantilever geometry on the optical lever sensitivities and thermal noise method of the atomic force microscope.

    PubMed

    Sader, John E; Lu, Jianing; Mulvaney, Paul

    2014-11-01

    Calibration of the optical lever sensitivities of atomic force microscope (AFM) cantilevers is especially important for determining the force in AFM measurements. These sensitivities depend critically on the cantilever mode used and are known to differ for static and dynamic measurements. Here, we calculate the ratio of the dynamic and static sensitivities for several common AFM cantilevers, whose shapes vary considerably, and experimentally verify these results. The dynamic-to-static optical lever sensitivity ratio is found to range from 1.09 to 1.41 for the cantilevers studied - in stark contrast to the constant value of 1.09 used widely in current calibration studies. This analysis shows that accuracy of the thermal noise method for the static spring constant is strongly dependent on cantilever geometry - neglect of these dynamic-to-static factors can induce errors exceeding 100%. We also discuss a simple experimental approach to non-invasively and simultaneously determine the dynamic and static spring constants and optical lever sensitivities of cantilevers of arbitrary shape, which is applicable to all AFM platforms that have the thermal noise method for spring constant calibration.

  2. The Offner imaging spectrometer in quadrature.

    PubMed

    Prieto-Blanco, Xesús; Montero-Orille, Carlos; González-Nuñez, Héctor; Mouriz, María Dolores; Lago, Elena López; de la Fuente, Raúl

    2010-06-07

    This is a proposal and description of a new configuration for an Offner imaging spectrometer based on the theory of aberrations of off-plane classical-ruled spherical diffraction gratings. This new spectrometer comprises a concave mirror used in double reflection and a convex reflection grating operating in quadrature, in a concentric layout. A very simple procedure obtains designs that are anastigmatic for a given point on the entrance slit and a given wavelength. Specific examples show that the performance of this type of system improves the performance of analogous conventional in-plane systems, when compactness and/or high spectral resolution is of fundamental importance.

  3. A Differential Interference Contrast-Based Light Microscopic System for Laser Microsurgery and Optical Trapping of Selected Chromosomes during Mitosis In Vivo

    NASA Astrophysics Data System (ADS)

    Cole, Richard W.; Khodjakov, Alexey; Wright, William H.; Rieder, Conly L.

    1995-10-01

    Laser microsurgery and laser-generated optical force traps (optical tweezers) are both valuable light microscopic-based approaches for studying intra- and extracellular motility processes, including chromosome segregation during mitosis. Here we describe a system in use in our laboratory that allows living cells to be followed by high-resolution differential interference contrast (DIC) video-enhanced time-lapse light microscopy while selected mitotic organelles and spindle components are subjected to laser microsurgery and/or manipulation with an optical force trap. This system couples the output from two different Neodymium-YAG lasers to the same inverted light microscope equipped with both phase-contrast and de Senarmont compensation DIC optics, a motorized stage, and a high-resolution low-light-level CCD camera. Unlike similar systems using phase-contrast optics, our DIC-based system can image living cells in thin optical sections without contamination due to phase halos or out-of-focus object information. These advantages greatly facilitate laser-based light microscopic studies on mitotic organelles and components, including spindle poles (centrosomes) and kinetochores, which are at or below the resolution limit of the light microscope and buried within a large complex structure. When used in conjunction with image processing and high-resolution object-tracking techniques, our system provides new information on the roles that kinetochores and spindle microtubules play during chromosome segregation in plant and animal cells.

  4. Note: A stand on the basis of atomic force microscope to study substrates for imaging optics

    SciTech Connect

    Chkhalo, N. I.; Salashchenko, N. N.; Zorina, M. V.

    2015-01-15

    A description of a stand based on atomic force microscopy (AFM) for roughness measurements of large optical components with arbitrary surfaces is given. The sample under study is mounted on a uniaxial goniometer which allows the sample to be tilted in the range of ±30°. The inclination enables the local normal along the axis of the probe to be established at any point of the surface under study. A comparison of the results of the measurement of noise and roughness of a flat quartz sample, in the range of spatial frequencies 0.025–70 μm{sup −1}, obtained from “standard” AFM and developed versions is given. Within the experimental error, the measurement results were equivalent. Examples of applications of the stand for the study of substrates for X-ray optics are presented.

  5. The optical fiber tip: an inherently light-coupled microscopic platform for micro- and nanotechnologies.

    PubMed

    Kostovski, Gorgi; Stoddart, Paul R; Mitchell, Arnan

    2014-06-18

    The flat tip of an optical fiber is a unique and unconventional platform for micro and nanotechnologies. The small cross-section and large aspect ratio of the fiber provide an inherently light-coupled substrate that is uniquely suited to remote, in vivo and in situ applications. However, these same characteristics challenge established fabrication technologies, which are best suited to large planar substrates. This review presents a broad overview of strategies for patterning the flat tip of an optical fiber. Techniques discussed include self-assembly, numerous lithographies, through-fiber patterning, hybrid techniques, and strategies for mass manufacture, while the diverse applications are discussed in context throughout. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Note: A stand on the basis of atomic force microscope to study substrates for imaging optics.

    PubMed

    Chkhalo, N I; Salashchenko, N N; Zorina, M V

    2015-01-01

    A description of a stand based on atomic force microscopy (AFM) for roughness measurements of large optical components with arbitrary surfaces is given. The sample under study is mounted on a uniaxial goniometer which allows the sample to be tilted in the range of ±30°. The inclination enables the local normal along the axis of the probe to be established at any point of the surface under study. A comparison of the results of the measurement of noise and roughness of a flat quartz sample, in the range of spatial frequencies 0.025-70 μm(-1), obtained from "standard" AFM and developed versions is given. Within the experimental error, the measurement results were equivalent. Examples of applications of the stand for the study of substrates for X-ray optics are presented.

  7. Parallel force measurement with a polymeric microbeam array using an optical microscope and micromanipulator.

    PubMed

    Sasoglu, F Mert; Bohl, Andrew J; Allen, Kathleen B; Layton, Bradley E

    2009-01-01

    An image analysis method and its validation are presented for tracking the displacements of parallel mechanical force sensors. Force is measured using a combination of beam theory, optical microscopy, and image analysis. The primary instrument is a calibrated polymeric microbeam array mounted on a micromanipulator with the intended purpose of measuring traction forces on cell cultures or cell arrays. One application is the testing of hypotheses involving cellular mechanotransduction mechanisms. An Otsu-based image analysis code calculates displacement and force on cellular or other soft structures by using edge detection and image subtraction on digitally captured optical microscopy images. Forces as small as 250+/-50 nN and as great as 25+/-2.5 microN may be applied and measured upon as few as one or as many as hundreds of structures in parallel. A validation of the method is provided by comparing results from a rigid glass surface and a compliant polymeric surface.

  8. A Scanning Magneto-Optical Kerr Microscope to study the Domain Pattern of Stressed Magnetic Thin Films

    NASA Astrophysics Data System (ADS)

    Geerts, Wilhelmus; ten Brinke, Hans-Willem; Garcia, S.

    2004-10-01

    A profound knowledge of the magneto-elastic properties of magnetic thin films is important if one wants to apply those materials in sensors. Irreproducible relaxation of the stress during the production process forces designers to use materials with small or zero magneto-elastic properties. A better understanding of the magneto-elastic properties is also relevant for the application of thin films in pressure, force, acceleration, and stress sensors. In order to study the magneto-elastic properties on a microscopic scale we developed a scanning magneto-optical Kerr microscope. The system is based on a modulating ellipsometer and includes a polarizer, sample, photo-elastic modulator, analyzer, and detector. The sample is mounted in a special pressure cell that can curve the surface of the thin film and induce an isotropic in-plane stress in the material. The laser beam is focused to a spot below 10 um and can be scanned over the surface. Domain images can be measured as a function of the applied magnetic field. We will explain the setup and show preliminary results measured on continuous and patterned sputtered NiFe-45wall motion is the dominant reversal mechanism even in the gratings.

  9. Scanning near-field optical microscope based on double-resonant fiber probe montage and its operation in liquids

    NASA Astrophysics Data System (ADS)

    Dukenbayev, K.; Sekatskii, S. K.; Serebryakov, D. V.; Zayats, A. V.; Dietler, G.

    2007-06-01

    The operation of the scanning near-field optical microscope based on the double-resonant montage of a fiber probe onto the tuning fork (working frequency of the latter, that is 32 kHz, coincides with the second resonance frequency of the bending oscillations of the free standing part of a fiber beam) in liquid is reported. It is shown that due to the peculiarities of the probe montage (initially large, around 3,000 - 5,500 quality factor of the dithering and long projection of the fiber beam beyond the tuning fork body) and microscope electronics, this SNOM is very fit to work in liquids. Quality factor of the sensor drops down to the values around 300 - 600 when the probe tip is submerged on the depth of 0.2 - 0.3 mm, thus remaining large enough to enable high quality imaging with rather small acting force value laying in the subnanoNewton region. We also discuss the joint liquid recipient construction which connects the liquid cell containing a sample with the large water reservoir via a flexible tube. This reservoir is placed onto separate Z-stage and hence the water level in the cell can be regulated independently from the sample position which facilitates the SNOM operation a lot.

  10. Modulator-free quadrature amplitude modulation signal synthesis

    PubMed Central

    Liu, Zhixin; Kakande, Joseph; Kelly, Brian; O’Carroll, John; Phelan, Richard; Richardson, David J.; Slavík, Radan

    2014-01-01

    The ability to generate high-speed on–off-keyed telecommunication signals by directly modulating a semiconductor laser’s drive current was one of the most exciting prospective applications of the nascent field of laser technology throughout the 1960s. Three decades of progress led to the commercialization of 2.5 Gbit s−1-per-channel submarine fibre optic systems that drove the growth of the internet as a global phenomenon. However, the detrimental frequency chirp associated with direct modulation forced industry to use external electro-optic modulators to deliver the next generation of on–off-keyed 10 Gbit s−1 systems and is absolutely prohibitive for today’s (>)100 Gbit s−1 coherent systems, which use complex modulation formats (for example, quadrature amplitude modulation). Here we use optical injection locking of directly modulated semiconductor lasers to generate complex modulation format signals showing distinct advantages over current and other currently researched solutions. PMID:25523757

  11. Output field-quadrature measurements and squeezing in ultrastrong cavity-QED

    NASA Astrophysics Data System (ADS)

    Stassi, Roberto; Savasta, Salvatore; Garziano, Luigi; Spagnolo, Bernardo; Nori, Franco

    2016-12-01

    We study the squeezing of output quadratures of an electro-magnetic field escaping from a resonator coupled to a general quantum system with arbitrary interaction strengths. The generalized theoretical analysis of output squeezing proposed here is valid for all the interaction regimes of cavity-quantum electrodynamics: from the weak to the strong, ultrastrong, and deep coupling regimes. For coupling rates comparable or larger then the cavity resonance frequency, the standard input-output theory for optical cavities fails to calculate the variance of output field-quadratures and predicts a non-negligible amount of output squeezing, even if the system is in its ground state. Here we show that, for arbitrary interaction strength and for general cavity-embedded quantum systems, no squeezing can be found in the output-field quadratures if the system is in its ground state. We also apply the proposed theoretical approach to study the output squeezing produced by: (i) an artificial two-level atom embedded in a coherently-excited cavity; and (ii) a cascade-type three-level system interacting with a cavity field mode. In the latter case the output squeezing arises from the virtual photons of the atom-cavity dressed states. This work extends the possibility of predicting and analyzing the results of continuous-variable optical quantum-state tomography when optical resonators interact very strongly with other quantum systems.

  12. [Sensitivity, precision and resolution of the optical microscope in the study of environmental pollution by asbestos fibers].

    PubMed

    Maddalon, G; Patroni, M; Trimarchi, R; Clerici, C; Occella, E

    1991-01-01

    The authors comment on the methods and equipment used in two Italian laboratories for sampling and microscopic phase contrast analysis of asbestos and other respirable fibres in the air of the general environment, i.e., the Dust Analysis Laboratory, Industrial Hygiene and Toxicology Department of the Institute of Occupational Health (Clinica del Lavoro), University of Milan and the Technical Microscopy Laboratory, Ground Resources and Land Control (Georisorse e Territorio) Department of Turin Polytechnic, which use identical methods. Airborne dust samples are taken with personal samplers, 1 l/min air flow (sample duration 4-8 h), filtering air on 25 mm diameter, 0.8 micropore cellulose filters (about 300 mm total net surface of dust deposit). The following equipment is used for counting and analysis of fibres: a) Clinica del Lavoro, Milan: Polyvar Reichert-Jung microscope, 500 magnitudes, Zernike positive phase contrast; numerical counting on 100 whole ocular fields, equal to 6.38% of the total net surface of dust deposit on the membrane; b) Turin Polytechnic: Leitz Ortholux microscope, 500 magnitudes, Heine and Zernike phase contrast with mean standard contrast; numerical counting on square grid, with explored surface total equal to 1.68% of the total net surface of dust deposit on the membrane. Measurements performed: Clinica del Lavoro, Milan: 2,980 since 1960; Turin Polytechnic: 875 since 1965. The sensitivity of the methods for counting airborne fibres is discussed, concluding that the methods used by the two laboratories have a sensitivity between 0.05 and 1.6 fibre/litre of air, according to the overall dustiness of the environment under study. Analysis of the accuracy of the optic determinations, based on the repeated counts, shows a repeatability of 0.4 (40%) within 95% confidence limits. A resolution power of 0.35 microns is reported; however, the possibility exists (and is normally achieved in analytical practice in both laboratories) of identifying and

  13. Micro optical power meter for direct in situ measurement of light transmitted from microscopic systems and focused on micro-samples.

    PubMed

    Zhang, Gangping; Huang, Yao-Xiong

    2012-08-01

    This paper reports a micro optical power meter which is able to perform effective and precise measurement on the optical power at the focus of different microscopic systems. The power meter can be easily placed on the stages of different microscopes and even partly immersed into solution to directly measure the optical power transmitted from the microscope objective and focused on the sample suspended in solution. The testing experiments demonstrated that the power meter has the characteristics of high precision, excellent linearity, high sensitivity, good stability, and high responding speed. It can accurately measure power levels from 0.1 to 50 mW in visible wavelength in various conditions and environments, which may encounter in practical applications. The optical power measurements using the power meter performed in some biological cell culturing solutions and in air for the same laser light reveal the first time that the powers measured in solutions were about 5%-8% greater than that measured in air at the same position. This not only suggests the necessity of performing direct measurement in situ in solution to obtain the real optical power projected on the suspended samples, but also indicates that such a micro optical power meter can meet almost all the requirements of optical power measurement in different fields from biomedicine to material sciences.

  14. Micro optical power meter for direct in situ measurement of light transmitted from microscopic systems and focused on micro-samples

    NASA Astrophysics Data System (ADS)

    Zhang, Gangping; Huang, Yao-Xiong

    2012-08-01

    This paper reports a micro optical power meter which is able to perform effective and precise measurement on the optical power at the focus of different microscopic systems. The power meter can be easily placed on the stages of different microscopes and even partly immersed into solution to directly measure the optical power transmitted from the microscope objective and focused on the sample suspended in solution. The testing experiments demonstrated that the power meter has the characteristics of high precision, excellent linearity, high sensitivity, good stability, and high responding speed. It can accurately measure power levels from 0.1 to 50 mW in visible wavelength in various conditions and environments, which may encounter in practical applications. The optical power measurements using the power meter performed in some biological cell culturing solutions and in air for the same laser light reveal the first time that the powers measured in solutions were about 5%-8% greater than that measured in air at the same position. This not only suggests the necessity of performing direct measurement in situ in solution to obtain the real optical power projected on the suspended samples, but also indicates that such a micro optical power meter can meet almost all the requirements of optical power measurement in different fields from biomedicine to material sciences.

  15. Imaging and detection of early stage dental caries with an all-optical photoacoustic microscope

    NASA Astrophysics Data System (ADS)

    Hughes, D. A.; Sampathkumar, A.; Longbottom, C.; Kirk, K. J.

    2015-01-01

    Tooth decay, at its earliest stages, manifests itself as small, white, subsurface lesions in the enamel. Current methods for detection in the dental clinic are visual and tactile investigations, and bite-wing X-ray radiographs. These techniques suffer from poor sensitivity and specificity at the earliest (and reversible) stages of the disease due to the small size (<100μm) of the lesion. A fine-resolution (600 nm) ultra-broadband (200 MHz) all-optical photoacoustic microscopy system was is used to image the early signs of tooth decay. Ex-vivo tooth samples exhibiting white spot lesions were scanned and were found to generate a larger (one order of magnitude) photoacoustic (PA) signal in the lesion regions compared to healthy enamel. The high contrast in the PA images potentially allows lesions to be imaged and measured at a much earlier stage than current clinical techniques allow. PA images were cross referenced with histology photographs to validate our experimental results. Our PA system provides a noncontact method for early detection of white-spot lesions with a high detection bandwidth that offers advantages over previously demonstrated ultrasound methods. The technique provides the sensing depth of an ultrasound system, but with the spatial resolution of an optical system.

  16. Coherent double-color interference microscope for traceable optical surface metrology

    NASA Astrophysics Data System (ADS)

    Malinovski, I.; França, R. S.; Bessa, M. S.; Silva, C. R.; Couceiro, I. B.

    2016-06-01

    Interference microscopy is an important field of dimensional surface metrology because it provides direct traceability of the measurements to the SI base unit definition of the metre. With a typical measurement range from micrometres to nanometres interference microscopy (IM) covers the gap between classic metrology and nanometrology, providing continuous transfer of dimensional metrology into new areas of nanoscience and nanotechnology. Therefore IM is considered to be an indispensable tool for traceable transfer of the metre unit to different instruments. We report here the metrological study of an absolute Linnik interference microscope (IM) based on two frequency stabilized lasers. The design permits the flexible use of both lasers for measurements depending on the demand of the concrete measurement task. By principle of operation IM is combination of imaging and phase-shifting interferometry (PSI). The traceability is provided by the wavelength reference, that is, a He-Ne 633 nm stabilized laser. The second laser source, that is, a Blue-Green 488 nm grating stabilized laser diode, is used for improvements of resolution, and also for resolving integer fringe discontinuities on sharp features of the surface. The IM was optimized for surface height metrology. We have performed the study of the systematic effects of the measurements. This study allowed us to improve the hardware and software of IM and to find corrections for main systematic errors. The IM is purposed for 1D to 3D height metrology and surface topography in an extended range from nanometres to micrometres. The advantages and disadvantages of the design and developed methods are discussed.

  17. Resolving three-dimensional shape of sub-50 nm wide lines with nanometer-scale sensitivity using conventional optical microscopes

    SciTech Connect

    Attota, Ravikiran Dixson, Ronald G.

    2014-07-28

    We experimentally demonstrate that the three-dimensional (3-D) shape variations of nanometer-scale objects can be resolved and measured with sub-nanometer scale sensitivity using conventional optical microscopes by analyzing 4-D optical data using the through-focus scanning optical microscopy (TSOM) method. These initial results show that TSOM-determined cross-sectional (3-D) shape differences of 30 nm–40 nm wide lines agree well with critical-dimension atomic force microscope measurements. The TSOM method showed a linewidth uncertainty of 1.22 nm (k = 2). Complex optical simulations are not needed for analysis using the TSOM method, making the process simple, economical, fast, and ideally suited for high volume nanomanufacturing process monitoring.

  18. Measurement of the microscopic viscosities of microfluids with a dynamic optical tweezers system

    PubMed Central

    Zhang, Yuquan; Wu, Xiaojing; Wang, Yijia; Zhu, Siwei; Gao, Bruce Z; Yuan, X-C

    2016-01-01

    Viscosity coefficients of microfluids—Newtonian and non-Newtonian—were explored through the rotational motion of a particle trapped by optical tweezers in a microflute. Unlike conventional methods based on viscometers, our microfluidic system employs samples of less than 30 µl to complete a measurement. Viscosity coefficients of ethanol and fetal bovine serum, as typical examples of Newtonian and non-Newtonian fluids, were obtained experimentally, and found to be in excellent agreement with theoretical predictions. Additionally, a practical application to a DNA solution with incremental ethidium bromide content was employed and the results are consistent with clinical data, indicating that our system provides a potentially important complementary tool for use in such biological and medical applications. PMID:27087769

  19. Energy-Dependent microscopic optical potential for p+{sup 9}Be elastic scattering

    SciTech Connect

    Maridi, H. M.; Farag, M. Y. H. Esmael, E. H.

    2016-06-10

    The p+{sup 9}Be elastic scattering at an energy range up to 200 MeV/nucleon is analyzed using the single-folding model. The density- and isospin-dependent M3Y-Paris nucleon-nucleon (NN) interaction is used for the real part and the NN-scattering amplitude of the high-energy approximation for the imaginary one. The analysis reveals that the cross-section data are reproduced well at energies up to 100 MeV/nucleon by use of the partial-wave expansion. For higher energies, the eikonal approximation give results better than the partial-wave expansion calculations. The volume integrals of the optical-potential parts have systematic energy dependencies, and they are parameterized in empirical formulas.

  20. Microscopic Modeling of Intersubband Optical Processes in Type II Semiconductor Quantum Wells: Linear Absorption

    NASA Technical Reports Server (NTRS)

    Li, Jian-Zhong; Kolokolov, Kanstantin I.; Ning, Cun-Zheng

    2003-01-01

    Linear absorption spectra arising from intersubband transitions in semiconductor quantum well heterostructures are analyzed using quantum kinetic theory by treating correlations to the first order within Hartree-Fock approximation. The resulting intersubband semiconductor Bloch equations take into account extrinsic dephasing contributions, carrier-longitudinal optical phonon interaction and carrier-interface roughness interaction which is considered with Ando s theory. As input for resonance lineshape calculation, a spurious-states-free 8-band kp Hamiltonian is used, in conjunction with the envelop function approximation, to compute self-consistently the energy subband structure of electrons in type II InAs/AlSb single quantum well structures. We demonstrate the interplay of nonparabolicity and many-body effects in the mid-infrared frequency range for such heterostructures.

  1. Ultrafast chirped optical waveform recorder using referenced heterodyning and a time microscope

    DOEpatents

    Bennett, Corey Vincent [Livermore, CA

    2011-11-22

    A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. This invention expands upon previous work in temporal imaging by adding heterodyning, which can be self-referenced for improved precision and stability, to convert frequency chirp (the second derivative of phase with respect to time) into a time varying intensity modulation. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

  2. Ultrafast chirped optical waveform recording using referenced heterodyning and a time microscope

    DOEpatents

    Bennett, Corey Vincent

    2010-06-15

    A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. This invention expands upon previous work in temporal imaging by adding heterodyning, which can be self-referenced for improved precision and stability, to convert frequency chirp (the second derivative of phase with respect to time) into a time varying intensity modulation. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

  3. Microscopic formulation of medium contributions to the first-order optical potential

    NASA Astrophysics Data System (ADS)

    Chinn, C. R.; Elster, Ch.; Thaler, R. M.

    1993-12-01

    A refinement of the first-order optical potential is introduced, consistent with multiple scattering theory and the spectator expansion. A systematic formalism is presented to treat medium contributions associated with the difference between the effective NN t matrix as required by multiple scattering theory and the free NN t matrix. A mean field potential is used to represent the action of the residual (A-1) nucleus upon the struck target nucleon (medium effects). We calculate elastic proton and neutron scattering from 40Ca, using the full Bonn interaction and two different mean field potentials taken from realistic and proven nuclear structure models. Results indicate that the medium contributions are insignificant at energies above 300 MeV and provide a significant improvement of the theoretical predictions for laboratory energies between 48 and 200 MeV.

  4. Image quality improvement in a hard X-ray projection microscope using total reflection mirror optics.

    PubMed

    Mimura, Hidekazu; Yamauchi, Kazuto; Yamamura, Kazuya; Kubota, Akihisa; Matsuyama, Satoshi; Sano, Yasuhisa; Ueno, Kazumasa; Endo, Katsuyoshi; Nishino, Yoshinori; Tamasaku, Kenji; Yabashi, Makina; Ishikawa, Tetsuya; Mori, Yuzo

    2004-07-01

    A new figure correction method has been applied in order to fabricate an elliptical mirror to realize a one-dimensionally diverging X-ray beam having high image quality. Mutual relations between figure errors and intensity uniformities of diverging X-ray beams have also been investigated using a wave-optical simulator and indicate that figure errors in relatively short spatial wavelength ranges lead to high-contrast interference fringes. By using a microstitching interferometer and elastic emission machining, figure correction of an elliptical mirror with a lateral resolution close to 0.1 mm was carried out. A one-dimensional diverging X-ray obtained using the fabricated mirror was observed at SPring-8 and evaluated to have a sufficiently flat intensity distribution.

  5. Observation of electrodeposited lithium by optical microscope in room temperature ionic liquid-based electrolyte

    NASA Astrophysics Data System (ADS)

    Sano, H.; Sakaebe, H.; Matsumoto, H.

    Room temperature ionic liquids (RTILs) were applied to a lithium (Li) metal battery system, and the behavior of Li electrodeposition on nickel electrodes in RTILs was investigated using in situ optical microscopy with/without an organic additive, vinylene carbonate (VC), in the RTILs. Two RTILs, PP13[TFSA] (N-methyl- N-propylpiperidinium bis(trifluoromethanesulfonyl)amide) and EMI[FSA] (1-ethyl-3-methylimidazolium bis(fluorosulfonyl)amide), were chosen as the base electrolytes. Dendritic particles were obtained in the case of EMI[FSA] with and without VC, and PP13[TFSA] without VC, while non-dendritic fine particles were obtained in the case of PP13[TFSA] with VC.

  6. Microscopic Modeling of Intersubband Optical Processes in Type II Semiconductor Quantum Wells: Linear Absorption

    NASA Technical Reports Server (NTRS)

    Li, Jian-Zhong; Kolokolov, Kanstantin I.; Ning, Cun-Zheng

    2003-01-01

    Linear absorption spectra arising from intersubband transitions in semiconductor quantum well heterostructures are analyzed using quantum kinetic theory by treating correlations to the first order within Hartree-Fock approximation. The resulting intersubband semiconductor Bloch equations take into account extrinsic dephasing contributions, carrier-longitudinal optical phonon interaction and carrier-interface roughness interaction which is considered with Ando s theory. As input for resonance lineshape calculation, a spurious-states-free 8-band kp Hamiltonian is used, in conjunction with the envelop function approximation, to compute self-consistently the energy subband structure of electrons in type II InAs/AlSb single quantum well structures. We demonstrate the interplay of nonparabolicity and many-body effects in the mid-infrared frequency range for such heterostructures.

  7. Extending the Chemical and Optical Sensitivity of the Scanning Tunneling Microscope

    NASA Astrophysics Data System (ADS)

    Yu, Arthur

    This dissertation discusses the theoretical basis and experimental applications to improving the capability of the STM in chemical and optical sensitivity. Traditional STM methods have achieved unprecedented spatial resolution, but suffer from a lack of sensitivity to chemical structure and composition. A new method of imaging, based on inelastic electron tunneling spectroscopy (IETS) measurement of hydrogen molecules is developed. The interaction of plasmon excitations to electronic states of a metal nano-cluster is also studied, allowing for better understanding of the mechanisms involved in the plasmon -- electron coupling. Since its application at the single molecule level in the STM was realized, IETS has been used to identify different molecules through their vibrational signal. In recent experiments, rotational excitation of H2 was detected on metal and insulator surfaces. It was found that the energy of these excitations depend sensitively on the local chemical environment. By monitoring the rotational and vibrational IETS signal of the H2 across the molecule, a more chemically sensitive image can be constructed. When the method is applied to imaging magnesium porphyrin (MgP) on Au (110), different components of the molecule can be observed at different energies. These differences are indication of how the various components interact with the H2. Optical sensitivity of the STM manifests in the detection of photons emitted from the tunnel junction. Previous experiments have shown that we can map the excitation of molecular fluorescence with sub-Angstrom resolution. For applications in photochemistry and catalysis, understanding how plasmons interact with photons and electrons is crucial. Light emission from Au nanoclusters on oxide shows strong correlation with their electronic states. The interaction between plasmon mode in the junction and electronic states of the nano-clusters is further studied through clusters of different sizes and dimers. Emission of

  8. Realization of a robust homodyne quadrature laser interferometer by performing wave plate yawing to realize ultra-low error sensitivity.

    PubMed

    Cui, Junning; He, Zhangqiang; Tan, Jiubin; Sun, Tao

    2016-10-03

    The deviation of wave plates' optical axes from their intended angles, which may result from either instability or assembly error, is the main cause of quadrature phase error in homodyne quadrature laser interferometers (HQLIs). The quadrature phase error sensitivity to wave plate angle deviations, which is an effective measure of HQLI robustness, is further amplified by beam splitter imperfections. In this paper, a new HQLI design involving non-polarization beam splitting is presented, and a method of making this HQLI robust by yawing the wave plates in the measurement and reference arms is proposed. The theoretical analysis results indicate that ultra-low quadrature phase error sensitivities to wave plate angle deviations can be realized and that non-polarizing beam splitter imperfections can be adequately compensated for. The experimental results demonstrate that the proposed method can reduce the quadrature phase error sensitivity by more than 1 order of magnitude, from a theoretical value of 1.4°/1° to 0.05°/1°.

  9. Signal of microstrip scanning near-field optical microscope in far- and near-field zones.

    PubMed

    Morozov, Yevhenii M; Lapchuk, Anatoliy S

    2016-05-01

    An analytical model of interference between an electromagnetic field of fundamental quasi-TM(EH)00-mode and an electromagnetic field of background radiation at the apex of a near-field probe based on an optical plasmon microstrip line (microstrip probe) has been proposed. The condition of the occurrence of electromagnetic energy reverse flux at the apex of the microstrip probe was obtained. It has been shown that the nature of the interference depends on the length of the probe. Numerical simulation of the sample scanning process was conducted in illumination-reflection and illumination-collection modes. Results of numerical simulation have shown that interference affects the scanning signal in both modes. However, in illumination-collection mode (pure near-field mode), the signal shape and its polarity are practically insensible to probe length change; only signal amplitude (contrast) is slightly changed. However, changing the probe length strongly affects the signal amplitude and shape in the illumination-reflection mode (the signal formed in the far-field zone). Thus, we can conclude that even small background radiation can significantly influence the signal in the far-field zone and has practically no influence on a pure near-field signal.

  10. Dark-gray soliton transformations: possibility to study microscopic quantum phenomena by nonlinear optical methods

    NASA Astrophysics Data System (ADS)

    Hernández-Tenorio, C.; Serkin, V. N.; Belyaeva, T. L.; Peña-Moreno, R.; Morales-Lara, L.

    2015-01-01

    The nonlinear Schrödinger equation (NLSE) model with an external harmonic potential is one of the most important in modern science. This model makes it possible to analyze a variety of nonlinear phenomena, in nonlinear optics and laser physics, biophysics and in the theory of Bose-Einstein condensation of atoms. It is shown that the main specific feature of the dynamics of dark GP matter wave solitons in a parabolic trap is the formation of solitons with dynamically changing form-factors producing the periodic variation in the modulation depth (the degree of "blackness") of dark solitons. In general, the period of dark soliton oscillations in trapping potential depends on the specific conditions of the experiment and does not coincide with the oscillation period of a linear quantum-mechanical oscillator. In the case of an immobile pedestal in the trap, the oscillation period of the black soliton considerably increases because of the periodic transformation of the black soliton to the gray one and vice versa. Surprisingly, that if the dark soliton is superimposed on the base pedestal oscillating in the trap and displaced from the trap center, the oscillation period of the dark soliton coincides with the period of oscillations of the linear harmonic oscillator, while the dynamics of the dark soliton is similar to that of a classical particle obeying the Newton mechanics laws.

  11. Low-frequency quadrature mode birdcage resonator.

    PubMed

    Borsboom, H M; Claasen-Vujcić, T; Gaykema, H J; Mehlkopf, T

    1997-03-01

    The birdcage resonator is frequently used in conventional MRI because of its excellent attributes. Its use in low-field MRI is restricted to field strengths higher than, for example, 0.1 T, dependent on the size of the coil. This is because of the intrinsically low inductance value of the birdcage coils. Furthermore, the sensitivity of the birdcage at low field strengths is significantly lower when compared to, for example, the solenoid. Both problems can be overcome with the multiturn technique and a novel wound birdcage coil. The quadrature mode wound birdcage coil presented in this paper can be used at frequencies as low as 100 kHz. Its sensitivity is also increased when compared to the conventional strip-ring birdcage. Homogeneity, effective volume, and methods to increase the resonator bandwidth to match the signal bandwidth are left intact. The latter is a typical low-field problem.

  12. The May 1997 SOHO-Ulysses Quadrature

    NASA Technical Reports Server (NTRS)

    Suess, Steven T.; Poletto, G.; Romoli, M.; Neugebauer, M.; Goldstein, B. E.; Simnett, G.

    2000-01-01

    We present results from the May 1997 SOHO-Ulysses quadrature, near sunspot minimum. Ulysses was at 5.1 AU, 100 north of the solar equator, and off the east limb. It was, by chance, also at the very northern edge of the streamer belt. Nevertheless, SWOOPS detected only slow, relatively smooth wind and there was no direct evidence of fast wind from the northern polar coronal hole or of mixing with fast wind. LASCO images show that the streamer belt at 10 N was narrow and sharp at the beginning and end of the two week observation interval, but broadened in the middle. A corresponding change in density, but not flow speed, occurred at Ulysses. Coronal densities derived from UVCS show that physical parameters in the lower corona are closely related to those in the solar wind, both over quiet intervals and in transient events on the limb. One small transient observed by both LASCO and UVCS is analyzed in detail.

  13. Fiber-optic laser-Doppler anemometer microscope developed for the measurement of microvascular red cell velocity.

    PubMed

    Seki, J

    1990-11-01

    A fiber-optic laser-Doppler anemometer microscope (FLDAM) was developed and its applicability to the study of microvascular blood flow was examined by measuring red cell velocities in vivo and in vitro. The FLDAM consists of an intravital microscope equipped with a fringe-mode back-scatter LDA. A data processing method of the Doppler signal which used frequency averaging over the entire frequency range of the power spectrum was developed. Spatial resolution of the FLDAM varied from 17 to 200 microns with 50X to 5X objectives. In vitro experiments showed that the red cell velocity obtained by the FLDAM was equal to the mean flow velocity, within the accuracy of the measurements, for tube diameters from 35 to 100 microns, mean velocity from 0.7 to 17 mm/sec, and feed hematocrit of 20%, when 10X or 20X objectives were used. In vivo red cell velocity measurements conducted with the FLDAM in microvessels of rat mesentery with diameters from 6.5 to 49 microns showed that red cell velocities were about 1/1.6 times smaller than those obtained by the two-slit technique, which also suggests that the velocity obtained by the FLDAM corresponds to the mean flow velocity. This relationship was also established from theoretical considerations for the case where the FLDAM sampling volume covers the entire vessel cross section. Furthermore the frequency response of the FLDAM was established to be about 20 Hz, which was sufficient for measurement of pulsatile velocities in rat mesenteric microvessels.

  14. Evaluation of an X-ray-excited optical microscope for chemical imaging of metal and other surfaces.

    PubMed

    Sabbe, Pieter-Jan; Dowsett, Mark; Hand, Matthew; Grayburn, Rosie; Thompson, Paul; Bras, Wim; Adriaens, Annemie

    2014-12-02

    The application of a modular system for the nondestructive chemical imaging of metal and other surfaces is described using heritage metals as an example. The custom-built X-ray-excited optical luminescence (XEOL) microscope, XEOM 1, images the chemical state and short-range atomic order of the top 200 nm of both amorphous and crystalline surfaces. A broad X-ray beam is used to illuminate large areas (up to 4 mm(2)) of the sample, and the resulting XEOL emission is collected simultaneously for each pixel by a charge-coupled device sensor to form an image. The input X-ray energy is incremented across a range typical for the X-ray absorption near-edge structure (XANES) and an image collected for each increment. The use of large-footprint beams combined with parallel detection allows the power density to be kept low and facilitates complete nondestructive XANES mapping on a reasonable time scale. In this study the microscope was evaluated by imaging copper surfaces with well-defined patterns of different corrosion products (cuprite Cu2O and nantokite CuCl). The images obtained show chemical contrast, and filtering the XEOL light allowed different corrosion products to be imaged separately. Absorption spectra extracted from software-selected regions of interest exhibit characteristic XANES fingerprints for the compounds present. Moreover, when the X-ray absorption edge positions were extracted from each spectrum, an oxidation state map of the sample could be compiled. The results show that this method allows one to obtain nondestructive and noninvasive information at the micrometer scale while using full-field imaging.

  15. Power flow control using quadrature boosters

    NASA Astrophysics Data System (ADS)

    Sadanandan, Sandeep N.

    A power system that can be controlled within security constraints would be an advantage to power planners and real-time operators. Controlling flows can lessen reliability issues such as thermal limit violations, power stability problems, and/or voltage stability conditions. Control of flows can also mitigate market issues by reducing congestion on some lines and rerouting power to less loaded lines or onto preferable paths. In the traditional control of power flows, phase shifters are often used. More advanced methods include using Flexible AC Transmission System (FACTS) Controllers. Some examples include Thyristor Controlled Series Capacitors, Synchronous Series Static Compensators, and Unified Power Flow Controllers. Quadrature Boosters (QBs) have similar structures to phase-shifters, but allow for higher voltage magnitude during real power flow control. In comparison with other FACTS controllers QBs are not as complex and not as expensive. The present study proposes to use QBs to control power flows on a power system. With the inclusion of QBs, real power flows can be controlled to desired scheduled values. In this thesis, the linearized power flow equations used for power flow analysis were modified for the control problem. This included modifying the Jacobian matrix, the power error vector, and calculating the voltage injected by the quadrature booster for the scheduled real power flow. Two scenarios were examined using the proposed power flow control method. First, the power flow in a line in a 5-bus system was modified with a QB using the method developed in this thesis. Simulation was carried out using Matlab. Second, the method was applied to a 30-bus system and then to a 118-bus system using several QBs. In all the cases, the calculated values of the QB voltages led to desired power flows in the designated line.

  16. Determination of feasibility and utility of microscope-integrated optical coherence tomography during ophthalmic surgery: the DISCOVER Study RESCAN Results.

    PubMed

    Ehlers, Justis P; Goshe, Jeff; Dupps, William J; Kaiser, Peter K; Singh, Rishi P; Gans, Richard; Eisengart, Jonathan; Srivastava, Sunil K

    2015-10-01

    Optical coherence tomography (OCT) has transformed the clinical management of a myriad of ophthalmic conditions. Applying OCT to ophthalmic surgery may have implications for surgical decision making and patient outcomes. To assess the feasibility and effect on surgical decision making of a microscope-integrated intraoperative OCT (iOCT) system. Report highlighting the 1-year results (March 2014-February 2015) of the RESCAN 700 portion of the DISCOVER (Determination of Feasibility of Intraoperative Spectral Domain Microscope Combined/Integrated OCT Visualization During En Face Retinal and Ophthalmic Surgery) study, a single-site, multisurgeon, prospective consecutive case series regarding this investigational device. Participants included patients undergoing ophthalmic surgery. Data on clinical characteristics were collected, and iOCT was performed during surgical milestones, as directed by the operating surgeon. A surgeon questionnaire was issued to each surgeon and was completed after each case to evaluate the role of iOCT during surgery and its particular role in select surgical procedures. Percentage of cases with successful acquisition of iOCT (ie, feasibility). Percentage of cases in which iOCT altered surgical decision making (ie, utility). During year 1 of the DISCOVER study, a total of 227 eyes (91 anterior segment cases and 136 posterior segment cases) underwent imaging with the RESCAN 700 system. Successful imaging (eg, the ability to acquire an OCT image of the tissue of interest) was obtained for 224 of 227 eyes (99% [95% CI, 98%-100%]). During lamellar keratoplasty, the iOCT data provided information that altered the surgeon's decision making in 38% of the cases (eg, complete graft apposition when the surgeon believed there was interface fluid). In membrane peeling procedures, iOCT information was discordant with the surgeon's impression of membrane peel completeness in 19% of cases (eg, lack of residual membrane or presence of occult membrane), thus

  17. Global analysis of isospin dependent microscopic nucleon-nucleus optical potentials in a Dirac-Brueckner-Hartree-Fock approach

    NASA Astrophysics Data System (ADS)

    Xu, Ruirui; Ma, Zhongyu; Zhang, Yue; Tian, Yuan; van Dalen, E. N. E.; Müther, H.

    2016-09-01

    Background: For the study of exotic nuclei it is important to have an optical model potential that is reliable not only for stable nuclei but can also be extrapolated to nuclear systems with exotic numbers of protons and neutrons. An efficient way to obtain such a potential is to develop a microscopic optical potential (MOP) based on a fundamental theory with a minimal number of free parameters, which are adjusted to describe stable nuclei all over the nuclide chart. Purpose: The choice adopted in the present work is to develop the MOP within a relativistic scheme which provides a natural and consistent relation between the spin-orbit part and the central part of the potential. The Dirac-Brueckner-Hartree-Fock (DBHF) approach provides such a microscopic relativistic scheme, which is based on a realistic nucleon-nucleon interaction and reproduces the saturation properties of symmetric nuclear matter without any adjustable parameter. Its solution using the projection technique within the subtracted T -matrix representation provides a reliable extension to asymmetric nuclear matter, which is important to describe the features of isospin asymmetric nuclei. The present work performs a global analysis of the isospin dependent nucleon-nucleus MOP based on the DBHF calculation in symmetric and asymmetric nuclear matter. Methods: The DBHF approach is used to evaluate the relativistic structure of the nucleon self-energies in nuclear matter at various densities and asymmetries. The Schrödinger equivalent potentials of finite nuclei are derived from these Dirac components by a local density approximation (LDA). The density distributions of finite nuclei are taken from the Hartree-Fock-Bogoliubov approach with Gogny D1S force. An improved LDA approach (ILDA) is employed to get a better prediction of the scattering observables. A χ2 assessment system based on the global simulated annealing algorithm is developed to optimize the very few free components in this study. Results

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

    PubMed Central

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

    2015-01-01

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

  19. Microscope collision protection apparatus

    DOEpatents

    DeNure, Charles R.

    2001-10-23

    A microscope collision protection apparatus for a remote control microscope which protects the optical and associated components from damage in the event of an uncontrolled collision with a specimen, regardless of the specimen size or shape. In a preferred embodiment, the apparatus includes a counterbalanced slide for mounting the microscope's optical components. This slide replaces the rigid mounts on conventional upright microscopes with a precision ball bearing slide. As the specimen contacts an optical component, the contacting force will move the slide and the optical components mounted thereon. This movement will protect the optical and associated components from damage as the movement causes a limit switch to be actuated, thereby stopping all motors responsible for the collision.

  20. New aspects of the structure of human hair on the basis of optical microscopic observations of disassembled hair parts.

    PubMed

    Yamauchi, Asao; Yamauchi, Kiyoshi

    2015-01-01

    Infant' and adult' scalp hair fibers were disassembled to various cellular components and blocks by chemical and enzymatic treatments, followed by random scission with rapidly rotating cutters. The hair fibers were also fractured by the use of a vise. The optical microscopic inspection of these specimens led to the discovery of many previously unknown structures in the hair shaft. In particular, a cuticular cell (Cu) was found to take a trowel-like shape consisting of a part with a blade-like shape (CuB) and a part with a handle-like shape (CuH), where CuB overlapped one another and fused partially to build the honeycomb-like structure on a large cuticular thin plate (CuP). Whereas CuH was closely similar to the cortical cell in dimensions and richness of macrofibrils (Mf). It was considered that human hair is stabilized structurally and physicochemically by the presence of the honeycomb-like structure, the CuP and the Mf.

  1. Enhanced defect detection capability using learning system for extreme ultraviolet lithography mask inspection tool with projection electron microscope optics

    NASA Astrophysics Data System (ADS)

    Hirano, Ryoichi; Hatakeyama, Masahiro; Terao, Kenji; Watanabe, Hidehiro

    2016-04-01

    Extreme ultraviolet lithography (EUVL) patterned mask defect detection is a major issue that must be addressed to realize EUVL-based device fabrication. We have designed projection electron microscope (PEM) optics for integration into a mask inspection system, and the resulting PEM system performs well in half-pitch (hp) 16-nm-node EUVL patterned mask inspection applications. A learning system has been used in this PEM patterned mask inspection tool. The PEM identifies defects using the "defectivity" parameter that is derived from the acquired image characteristics. The learning system has been developed to reduce the labor and the costs associated with adjustment of the PEM's detection capabilities to cope with newly defined mask defects. The concepts behind this learning system and the parameter optimization flow are presented here. The learning system for the PEM is based on a library of registered defects. The learning system then optimizes the detection capability by reconciling previously registered defects with newly registered defects. Functional verification of the learning system is also described, and the system's detection capability is demonstrated by applying it to the inspection of hp 11-nm EUV masks. We can thus provide a user-friendly mask inspection system with reduced cost of ownership.

  2. Three-dimensional registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation.

    PubMed

    Prabhu, David; Mehanna, Emile; Gargesha, Madhusudhana; Brandt, Eric; Wen, Di; van Ditzhuijzen, Nienke S; Chamie, Daniel; Yamamoto, Hirosada; Fujino, Yusuke; Alian, Ali; Patel, Jaymin; Costa, Marco; Bezerra, Hiram G; Wilson, David L

    2016-04-01

    Evidence suggests high-resolution, high-contrast, [Formula: see text] intravascular optical coherence tomography (IVOCT) can distinguish plaque types, but further validation is needed, especially for automated plaque characterization. We developed experimental and three-dimensional (3-D) registration methods to provide validation of IVOCT pullback volumes using microscopic, color, and fluorescent cryo-image volumes with optional registered cryo-histology. A specialized registration method matched IVOCT pullback images acquired in the catheter reference frame to a true 3-D cryo-image volume. Briefly, an 11-parameter registration model including a polynomial virtual catheter was initialized within the cryo-image volume, and perpendicular images were extracted, mimicking IVOCT image acquisition. Virtual catheter parameters were optimized to maximize cryo and IVOCT lumen overlap. Multiple assessments suggested that the registration error was better than the [Formula: see text] spacing between IVOCT image frames. Tests on a digital synthetic phantom gave a registration error of only [Formula: see text] (signed distance). Visual assessment of randomly presented nearby frames suggested registration accuracy within 1 IVOCT frame interval ([Formula: see text]). This would eliminate potential misinterpretations confronted by the typical histological approaches to validation, with estimated 1-mm errors. The method can be used to create annotated datasets and automated plaque classification methods and can be extended to other intravascular imaging modalities.

  3. Substrate-Dependence of the Freezing Dynamics of Supercooled Water Films: A High-Speed Optical Microscope Study.

    PubMed

    Pach, Elzbieta; Rodríguez, Laura; Verdaguer, Albert

    2017-09-18

    The freezing of supercooled water films on silicon-based surfaces was investigated using a high-speed camera coupled to an optical microscope. We were able to study in detail the two phases or stages in during water freezing; the first stage, faster, when dendritic grow occurs co-planar with the cold surface of the substrate and the second stage, slower, when the ice formed on the surface grows vertically until all the film is frozen. Several differentiated processes were identified during the freezing: two dimensional dendrite growing on the substrate interface, vertical dendrite growing, formation and evolution of ice domains, trapping of air bubbles in ice and freezing of the water film surface. We found all this process to be dependent on the supercooling temperature and the substrate used. Dendrite/ice front growing was found to be dependent on thermal properties of the substrate but could not to be unequivocally related to them. Finally for low supercooling it was observed a direct relationship between the morphology of the dendrites formed in the first stage, which depends on the substrate and the roughness and shape of the surface of the ice, when frozen of the film was completed.

  4. New approach to optical diffraction tomography yielding a vector equation of diffraction tomography and a novel tomographic microscope.

    PubMed

    Lauer, V

    2002-02-01

    We first obtain a frequency-space equation of diffraction tomography for the electric field vector, within the first-order Born approximation, using a simplified formalism resulting from using three-dimensional spatial frequencies and replacing outgoing waves by linear combinations of homogeneous plane waves. A coherent optical diffraction tomographic microscope is then described, in which a sample is successively illuminated by a series of plane waves having different directions, each scattered wave is recorded by phase-shifting interferometry, and the object is then reconstructed from these recorded waves. The measurement process in this device is analysed taking into account the illuminating wave, the wave scattered by the sample, the reference wave, and the phase relations between these waves. This analysis yields appropriate equations that take into account the characteristics of the reference wave and compensate random phase shifts. It makes it possible to obtain a high-resolution three-dimensional frequency representation in full conformity with theory. The experimentally obtained representations show index and absorptivity with a resolution limit of about a quarter of a wavelength, and have a depth of field of about 40 microm.

  5. Three-dimensional registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation

    PubMed Central

    Prabhu, David; Mehanna, Emile; Gargesha, Madhusudhana; Brandt, Eric; Wen, Di; van Ditzhuijzen, Nienke S.; Chamie, Daniel; Yamamoto, Hirosada; Fujino, Yusuke; Alian, Ali; Patel, Jaymin; Costa, Marco; Bezerra, Hiram G.; Wilson, David L.

    2016-01-01

    Abstract. Evidence suggests high-resolution, high-contrast, 100  frames/s intravascular optical coherence tomography (IVOCT) can distinguish plaque types, but further validation is needed, especially for automated plaque characterization. We developed experimental and three-dimensional (3-D) registration methods to provide validation of IVOCT pullback volumes using microscopic, color, and fluorescent cryo-image volumes with optional registered cryo-histology. A specialized registration method matched IVOCT pullback images acquired in the catheter reference frame to a true 3-D cryo-image volume. Briefly, an 11-parameter registration model including a polynomial virtual catheter was initialized within the cryo-image volume, and perpendicular images were extracted, mimicking IVOCT image acquisition. Virtual catheter parameters were optimized to maximize cryo and IVOCT lumen overlap. Multiple assessments suggested that the registration error was better than the 200-μm spacing between IVOCT image frames. Tests on a digital synthetic phantom gave a registration error of only +1.3±2.7  μm (signed distance). Visual assessment of randomly presented nearby frames suggested registration accuracy within 1 IVOCT frame interval (−25.0±174.3  μm). This would eliminate potential misinterpretations confronted by the typical histological approaches to validation, with estimated 1-mm errors. The method can be used to create annotated datasets and automated plaque classification methods and can be extended to other intravascular imaging modalities. PMID:27429997

  6. A Comparison of three high-precision quadrature schemes

    SciTech Connect

    Bailey, David H.; Li, Xiaoye S.

    2003-07-01

    The authors have implemented three numerical quadrature schemes, using the new Arbitrary Precision (ARPREC) software package, with the objective of seeking a completely ''automatic'' arbitrary precision quadrature facility, namely one that does not rely on a priori information of the function to be integrated. Such a facility is required, for example, to permit the experimental identification of definite integrals based on their numerical values. The performance and accuracy of these three quadrature schemes are compared using a suite of 15 integrals, ranging from continuous, well-behaved functions on finite intervals to functions with vertical derivatives and integrable singularities at endpoints, as well as several integrals on an infinite interval.

  7. Two-step-only quadrature phase-shifting digital holography.

    PubMed

    Liu, Jung-Ping; Poon, Ting-Chung

    2009-02-01

    Conventional methods of quadrature phase-shifting holography require two holograms and either intensity distribution of the reference wave or that of the object wave to reconstruct an original object without the zero order and the twin-image noise in an on-axis holographic recording setup. We present a technique called two-step-only quadrature phase-shifting holography in which solely two quadrature-phase holograms are required. Neither reference-wave intensity nor an object-wave intensity measurement is needed in the technique.

  8. Quantitative phase imaging using grating-based quadrature phase interferometer

    NASA Astrophysics Data System (ADS)

    Wu, Jigang; Yaqoob, Zahid; Heng, Xin; Cui, Xiquan; Yang, Changhuei

    2007-02-01

    In this paper, we report the use of holographic gratings, which act as the free-space equivalent of the 3x3 fiber-optic coupler, to perform full field phase imaging. By recording two harmonically-related gratings in the same holographic plate, we are able to obtain nontrivial phase shift between different output ports of the gratings-based Mach-Zehnder interferometer. The phase difference can be adjusted by changing the relative phase of the recording beams when recording the hologram. We have built a Mach-Zehnder interferometer using harmonically-related holographic gratings with 600 and 1200 lines/mm spacing. Two CCD cameras at the output ports of the gratings-based Mach-Zehnder interferometer are used to record the full-field quadrature interferograms, which are subsequently processed to reconstruct the phase image. The imaging system has ~12X magnification with ~420μmx315μm field-of-view. To demonstrate the capability of our system, we have successfully performed phase imaging of a pure phase object and a paramecium caudatum.

  9. Radiation transport modeling using extended quadrature method of moments

    SciTech Connect

    Vikas, V.; Hauck, C.D.; Wang, Z.J.; Fox, R.O.

    2013-08-01

    The radiative transfer equation describes the propagation of radiation through a material medium. While it provides a highly accurate description of the radiation field, the large phase space on which the equation is defined makes it numerically challenging. As a consequence, significant effort has gone into the development of accurate approximation methods. Recently, an extended quadrature method of moments (EQMOM) has been developed to solve univariate population balance equations, which also have a large phase space and thus face similar computational challenges. The distinct advantage of the EQMOM approach over other moment methods is that it generates moment equations that are consistent with a positive phase space density and has a moment inversion algorithm that is fast and efficient. The goal of the current paper is to present the EQMOM method in the context of radiation transport, to discuss advantages and disadvantages, and to demonstrate its performance on a set of standard one-dimensional benchmark problems that encompass optically thin, thick, and transition regimes. Special attention is given in the implementation to the issue of realizability—that is, consistency with a positive phase space density. Numerical results in one dimension are promising and lay the foundation for extending the same framework to multiple dimensions.

  10. Multidimensional deconvolution of optical microscope and ultrasound imaging using adaptive least-mean-square (LMS) inverse filtering

    NASA Astrophysics Data System (ADS)

    Sapia, Mark Angelo

    2000-11-01

    Three-dimensional microscope images typically suffer from reduced resolution due to the effects of convolution, optical aberrations and out-of-focus blurring. Two- dimensional ultrasound images are also degraded by convolutional bluffing and various sources of noise. Speckle noise is a major problem in ultrasound images. In microscopy and ultrasound, various methods of digital filtering have been used to improve image quality. Several methods of deconvolution filtering have been used to improve resolution by reversing the convolutional effects, many of which are based on regularization techniques and non-linear constraints. The technique discussed here is a unique linear filter for deconvolving 3D fluorescence microscopy or 2D ultrasound images. The process is to solve for the filter completely in the spatial-domain using an adaptive algorithm to converge to an optimum solution for de-blurring and resolution improvement. There are two key advantages of using an adaptive solution: (1)it efficiently solves for the filter coefficients by taking into account all sources of noise and degraded resolution at the same time, and (2)achieves near-perfect convergence to the ideal linear deconvolution filter. This linear adaptive technique has other advantages such as avoiding artifacts of frequency-domain transformations and concurrent adaptation to suppress noise. Ultimately, this approach results in better signal-to-noise characteristics with virtually no edge-ringing. Many researchers have not adopted linear techniques because of poor convergence, noise instability and negative valued data in the results. The methods presented here overcome many of these well-documented disadvantages and provide results that clearly out-perform other linear methods and may also out-perform regularization and constrained algorithms. In particular, the adaptive solution is most responsible for overcoming the poor performance associated with linear techniques. This linear adaptive approach to

  11. Adaptive Quadrature Detection for Multicarrier Continuous-Variable Quantum Key Distribution

    NASA Astrophysics Data System (ADS)

    Gyongyosi, Laszlo; Imre, Sandor

    2015-03-01

    We propose the adaptive quadrature detection for multicarrier continuous-variable quantum key distribution (CVQKD). A multicarrier CVQKD scheme uses Gaussian subcarrier continuous variables for the information conveying and Gaussian sub-channels for the transmission. The proposed multicarrier detection scheme dynamically adapts to the sub-channel conditions using a corresponding statistics which is provided by our sophisticated sub-channel estimation procedure. The sub-channel estimation phase determines the transmittance coefficients of the sub-channels, which information are used further in the adaptive quadrature decoding process. We define the technique called subcarrier spreading to estimate the transmittance conditions of the sub-channels with a theoretical error-minimum in the presence of a Gaussian noise. We introduce the terms of single and collective adaptive quadrature detection. We also extend the results for a multiuser multicarrier CVQKD scenario. We prove the achievable error probabilities, the signal-to-noise ratios, and quantify the attributes of the framework. The adaptive detection scheme allows to utilize the extra resources of multicarrier CVQKD and to maximize the amount of transmittable information. This work was partially supported by the GOP-1.1.1-11-2012-0092 (Secure quantum key distribution between two units on optical fiber network) project sponsored by the EU and European Structural Fund, and by the COST Action MP1006.

  12. Algorithm 699 - A new representation of Patterson's quadrature formulae

    NASA Technical Reports Server (NTRS)

    Krogh, Fred T.; Van Snyder, W.

    1991-01-01

    A method is presented to reduce the number of coefficients necessary to represent Patterson's quadrature formulae. It also reduces the amount of storage necessary for storing function values, and produces slightly smaller error in evaluating the formulae.

  13. Conditional homodyne detection of light with squeezed quadrature fluctuations

    SciTech Connect

    Vines, Justin; Vyas, Reeta; Singh, Surendra

    2006-08-15

    We discuss the detection of field quadrature fluctuations in conditional homodyne detection experiments and possible sources of error in such an experiment. We also present modifications to these experiments to help eliminate such errors and extend their range of applicability.

  14. Two integrator loop quadrature oscillators: A review

    PubMed Central

    Soliman, Ahmed M.

    2012-01-01

    A review of the two integrator loop oscillator circuits providing two quadrature sinusoidal output voltages is given. All the circuits considered employ the minimum number of capacitors namely two except one circuit which uses three capacitors. The circuits considered are classified to four different classes. The first class includes floating capacitors and floating resistors and the active building blocks realizing these circuits are the Op Amp or the OTRA. The second class employs grounded capacitors and includes floating resistors and the active building blocks realizing these circuits are the DCVC or the unity gain cells or the CFOA. The third class employs grounded capacitors and grounded resistors and the active building blocks realizing these circuits are the CCII. The fourth class employs grounded capacitors and no resistors and the active building blocks realizing these circuits are the TA. Transformation methods showing the generation of different classes from each other is given in details and this is one of the main objectives of this paper. PMID:25685396

  15. Radial Basis Function Based Quadrature over Smooth Surfaces

    DTIC Science & Technology

    2016-03-24

    weights for a particular node set. This thesis expands upon the same spherical quadrature method and applies it to an arbitrary smooth closed surface...recent technique 1 for spherical quadrature is expanded upon in Chapter II and adapted for use in approximating integrals of arbitrary smooth closed...logN) operations and O(N) memory usage. When expanding the computation of weights beyond one core, parallel scalability with number of cores was also

  16. The Light Microscope.

    ERIC Educational Resources Information Center

    Baker, W. L.

    1995-01-01

    Describes the function of the various parts of the microscope and their integration in the formation of an optical image. Presents a procedure for setting up a microscope to obtain maximum resolution and contrast for each objective lens at all magnifications. (JRH)

  17. Photography through the Microscope.

    ERIC Educational Resources Information Center

    McNeil, D. W.

    1992-01-01

    Describes how to illuminate and optically stain slides for microscope use and how to interface a 35mm camera with a microscope using an adaptor. Provides equipment descriptions and sources, details about illumination, image formation, darkfield adaptors, centerable filter adaptors, darkfield stops, rheinburg filters, and choosing specimens to…

  18. Assessment of Petrological Microscopes.

    ERIC Educational Resources Information Center

    Mathison, Charter Innes

    1990-01-01

    Presented is a set of procedures designed to check the design, ergonomics, illumination, function, optics, accessory equipment, and image quality of a microscope being considered for purchase. Functions for use in a petrology or mineralogy laboratory are stressed. (CW)

  19. Assessment of Petrological Microscopes.

    ERIC Educational Resources Information Center

    Mathison, Charter Innes

    1990-01-01

    Presented is a set of procedures designed to check the design, ergonomics, illumination, function, optics, accessory equipment, and image quality of a microscope being considered for purchase. Functions for use in a petrology or mineralogy laboratory are stressed. (CW)

  20. Quadrature mixture LO suppression via DSW DAC noise dither

    DOEpatents

    Dubbert, Dale F.; Dudley, Peter A.

    2007-08-21

    A Quadrature Error Corrected Digital Waveform Synthesizer (QECDWS) employs frequency dependent phase error corrections to, in effect, pre-distort the phase characteristic of the chirp to compensate for the frequency dependent phase nonlinearity of the RF and microwave subsystem. In addition, the QECDWS can employ frequency dependent correction vectors to the quadrature amplitude and phase of the synthesized output. The quadrature corrections cancel the radars' quadrature upconverter (mixer) errors to null the unwanted spectral image. A result is the direct generation of an RF waveform, which has a theoretical chirp bandwidth equal to the QECDWS clock frequency (1 to 1.2 GHz) with the high Spurious Free Dynamic Range (SFDR) necessary for high dynamic range radar systems such as SAR. To correct for the problematic upconverter local oscillator (LO) leakage, precision DC offsets can be applied over the chirped pulse using a pseudo-random noise dither. The present dither technique can effectively produce a quadrature DC bias which has the precision required to adequately suppress the LO leakage. A calibration technique can be employed to calculate both the quadrature correction vectors and the LO-nulling DC offsets using the radar built-in test capability.

  1. Intrasurgical Human Retinal Imaging With Manual Instrument Tracking Using a Microscope-Integrated Spectral-Domain Optical Coherence Tomography Device

    PubMed Central

    Hahn, Paul; Carrasco-Zevallos, Oscar; Cunefare, David; Migacz, Justin; Farsiu, Sina; Izatt, Joseph A.; Toth, Cynthia A.

    2015-01-01

    Purpose: To characterize the first in-human intraoperative imaging using a custom prototype spectral-domain microscope-integrated optical coherence tomography (MIOCT) device during vitreoretinal surgery with instruments in the eye. Methods: Under institutional review board approval for a prospective intraoperative study, MIOCT images were obtained at surgical pauses with instruments held static in the vitreous cavity and then concurrently with surgical maneuvers. Postoperatively, MIOCT images obtained at surgical pauses were compared with images obtained with a high-resolution handheld spectral-domain OCT (HHOCT) system with objective endpoints, including acquisition of images acceptable for analysis and identification of predefined macular morphologic or pathologic features. Results: Human MIOCT images were successfully obtained before incision and during pauses in surgical maneuvers. MIOCT imaging confirmed preoperative diagnoses, such as epiretinal membrane, full-thickness macular hole, and vitreomacular traction and demonstrated successful achievement of surgical goals. MIOCT and HHOCT images obtained at surgical pauses in two cohorts of five patients were comparable with greater than or equal to 80% correlation in 80% of patients. Real-time video-imaging concurrent with surgical manipulations enabled, for the first time using this device, visualization of dynamic instrument-retina interaction with targeted OCT tracking. Conclusion: MIOCT is successful for imaging at surgical pauses and for real-time image guidance with implementation of targeted OCT tracking. Even faster acquisition speeds are currently being developed with incorporation of a swept-source MIOCT engine. Further refinements and investigations will be directed toward continued integration for real-time volumetric imaging of surgical maneuvers. Translational Relevance: Ongoing development of seamless MIOCT systems will likely transform surgical visualization, approaches, and decision-making. PMID

  2. 3D registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation

    PubMed Central

    Prabhu, David; Mehanna, Emile; Gargesha, Madhusudhana; Wen, Di; Brandt, Eric; van Ditzhuijzen, Nienke S.; Chamie, Daniel; Yamamoto, Hirosada; Fujino, Yusuke; Farmazilian, Ali; Patel, Jaymin; Costa, Marco; Bezerra, Hiram G.; Wilson, David L.

    2016-01-01

    High resolution, 100 frames/sec intravascular optical coherence tomography (IVOCT) can distinguish plaque types, but further validation is needed, especially for automated plaque characterization. We developed experimental and 3D registration methods, to provide validation of IVOCT pullback volumes using microscopic, brightfield and fluorescent cryo-image volumes, with optional, exactly registered cryo-histology. The innovation was a method to match an IVOCT pull-back images, acquired in the catheter reference frame, to a true 3D cryo-image volume. Briefly, an 11-parameter, polynomial virtual catheter was initialized within the cryo-image volume, and perpendicular images were extracted, mimicking IVOCT image acquisition. Virtual catheter parameters were optimized to maximize cryo and IVOCT lumen overlap. Local minima were possible, but when we started within reasonable ranges, every one of 24 digital phantom cases converged to a good solution with a registration error of only +1.34±2.65μm (signed distance). Registration was applied to 10 ex-vivo cadaver coronary arteries (LADs), resulting in 10 registered cryo and IVOCT volumes yielding a total of 421 registered 2D-image pairs. Image overlays demonstrated high continuity between vascular and plaque features. Bland-Altman analysis comparing cryo and IVOCT lumen area, showed mean and standard deviation of differences as 0.01±0.43 mm2. DICE coefficients were 0.91±0.04. Finally, visual assessment on 20 representative cases with easily identifiable features suggested registration accuracy within one frame of IVOCT (±200μm), eliminating significant misinterpretations introduced by 1mm errors in the literature. The method will provide 3D data for training of IVOCT plaque algorithms and can be used for validation of other intravascular imaging modalities. PMID:27162417

  3. 3D registration of intravascular optical coherence tomography and cryo-image volumes for microscopic-resolution validation

    NASA Astrophysics Data System (ADS)

    Prabhu, David; Mehanna, Emile; Gargesha, Madhusudhana; Wen, Di; Brandt, Eric; van Ditzhuijzen, Nienke S.; Chamie, Daniel; Yamamoto, Hirosada; Fujino, Yusuke; Farmazilian, Ali; Patel, Jaymin; Costa, Marco; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    High resolution, 100 frames/sec intravascular optical coherence tomography (IVOCT) can distinguish plaque types, but further validation is needed, especially for automated plaque characterization. We developed experimental and 3D registration methods, to provide validation of IVOCT pullback volumes using microscopic, brightfield and fluorescent cryoimage volumes, with optional, exactly registered cryo-histology. The innovation was a method to match an IVOCT pullback images, acquired in the catheter reference frame, to a true 3D cryo-image volume. Briefly, an 11-parameter, polynomial virtual catheter was initialized within the cryo-image volume, and perpendicular images were extracted, mimicking IVOCT image acquisition. Virtual catheter parameters were optimized to maximize cryo and IVOCT lumen overlap. Local minima were possible, but when we started within reasonable ranges, every one of 24 digital phantom cases converged to a good solution with a registration error of only +1.34+/-2.65μm (signed distance). Registration was applied to 10 ex-vivo cadaver coronary arteries (LADs), resulting in 10 registered cryo and IVOCT volumes yielding a total of 421 registered 2D-image pairs. Image overlays demonstrated high continuity between vascular and plaque features. Bland- Altman analysis comparing cryo and IVOCT lumen area, showed mean and standard deviation of differences as 0.01+/-0.43 mm2. DICE coefficients were 0.91+/-0.04. Finally, visual assessment on 20 representative cases with easily identifiable features suggested registration accuracy within one frame of IVOCT (+/-200μm), eliminating significant misinterpretations introduced by 1mm errors in the literature. The method will provide 3D data for training of IVOCT plaque algorithms and can be used for validation of other intravascular imaging modalities.

  4. [Stereo microscope, neglected tool].

    PubMed

    Gacek, Grzegorz

    2017-01-01

    Stereoscopes, in author opinion, are neglected tools in modern biology. This article shortly describes technical and application capabilities of the present stereomicroscopes. The two main types of stereomicroscope construction are depicted: Greenough microscope and Common Main Objective microscope. The technological breakthrough, asymmetrical optical design of stereomicroscopes, the Fusion Optics, is presented too. Because of very wide offer of a stereomicroscope platforms, illumination systems, software and imaging systems, the article contains also very useful factors to consider when selecting a stereomicroscope.

  5. Combined use of optical and electron microscopic techniques for the measurement of hygroscopic property, chemical composition, and morphology of individual aerosol particles.

    PubMed

    Ahn, Kang-Ho; Kim, Sun-Man; Jung, Hae-Jin; Lee, Mi-Jung; Eom, Hyo-Jin; Maskey, Shila; Ro, Chul-Un

    2010-10-01

    In this work, an analytical method for the characterization of the hygroscopic property, chemical composition, and morphology of individual aerosol particles is introduced. The method, which is based on the combined use of optical and electron microscopic techniques, is simple and easy to apply. An optical microscopic technique was used to perform the visual observation of the phase transformation and hygroscopic growth of aerosol particles on a single particle level. A quantitative energy-dispersive electron probe X-ray microanalysis, named low-Z particle EPMA, was used to perform a quantitative chemical speciation of the same individual particles after the measurement of the hygroscopic property. To validate the analytical methodology, the hygroscopic properties of artificially generated NaCl, KCl, (NH(4))(2)SO(4), and Na(2)SO(4) aerosol particles of micrometer size were investigated. The practical applicability of the analytical method for studying the hygroscopic property, chemical composition, and morphology of ambient aerosol particles is demonstrated.

  6. Initial experience with a robotically operated video optical telescopic-microscope in cranial neurosurgery: feasibility, safety, and clinical applications.

    PubMed

    Gonen, Lior; Chakravarthi, Srikant S; Monroy-Sosa, Alejandro; Celix, Juanita M; Kojis, Nathaniel; Singh, Maharaj; Jennings, Jonathan; Fukui, Melanie B; Rovin, Richard A; Kassam, Amin B

    2017-05-01

    OBJECTIVE The move toward better, more effective optical visualization in the field of neurosurgery has been a focus of technological innovation. In this study, the authors' objectives are to describe the feasibility and safety of a new robotic optical platform, namely, the robotically operated video optical telescopic-microscope (ROVOT-m), in cranial microsurgical applications. METHODS A prospective database comprising patients who underwent a cranial procedure between April 2015 and September 2016 was queried, and the first 200 patients who met the inclusion criteria were selected as the cohort for a retrospective chart review. Only adults who underwent microsurgical procedures in which the ROVOT-m was used were considered for the study. Preoperative, intraoperative, and postoperative data were retrieved from electronic medical records. The authors address the feasibility and safety of the ROVOT-m by studying various intraoperative variables and by reporting perioperative morbidity and mortality, respectively. To assess the learning curve, cranial procedures were categorized into 6 progressively increasing complexity groups. The main categories of pathology were I) intracerebral hemorrhages (ICHs); II) intraaxial tumors involving noneloquent regions or noncomplex extraaxial tumors; III) intraaxial tumors involving eloquent regions; IV) skull base pathologies; V) intraventricular lesions; and VI) cerebrovascular lesions. In addition, the entire cohort was evenly divided into early and late cohorts. RESULTS The patient cohort comprised 104 female (52%) and 96 male (48%) patients with a mean age of 56.7 years. The most common pathological entities encountered were neoplastic lesions (153, 76.5%), followed by ICH (20, 10%). The distribution of cases by complexity categories was 11.5%, 36.5%, 22%, 20%, 3.5%, and 6.5% for Categories I, II, II, IV, V, and VI, respectively. In all 200 cases, the surgical goal was achieved without the need for intraoperative conversion

  7. Full quadrature regeneration of QPSK signals using sequential phase sensitive amplification and parametric saturation.

    PubMed

    Bottrill, K R H; Hesketh, G; Jones, L; Parmigiani, F; Richardson, D J; Petropoulos, P

    2017-01-23

    We demonstrate all-optical regeneration of both the phase and the amplitude of a 10 GBaud quadrature phase shift keying (QPSK) signal using two nonlinear stages. First we regenerate the phase using a wavelength converting phase sensitive amplifier and then we regenerate the amplitude using a saturated single-pump parametric amplifier, returning the signal to its original wavelength at the same time. We exploit the conjugating nature of the two processing stages to eliminate the intrinsic SPM distortion of the system, further improving performance.

  8. Optimization of quadrature signal processing for laser interferometers for demanding applications

    NASA Astrophysics Data System (ADS)

    PodŻorny, Tomasz; Budzyń, Grzegorz; Tkaczyk, Jakub

    2016-06-01

    Presented paper performs an analysis of quadrature signal processing algorithms for high demanding laser interferometry applications. Careful signal processing is required to minimize nonlinearities which come from optical path and components' imperfections, and reduce overall instrumental error. Paper focuses on algebraic fits, because implementation for real time systems was a main requirement. The most demanding applications are stationary measurements where the position slightly fluctuates in the range below one fringe period. Therefore, analysis was performed for samples that were spread along a few milliradians of a full circle.

  9. Spectral Properties of Soil Grains as Inferred from Images of the Optical Microscope onboard the Phoenix Mars Lander

    NASA Astrophysics Data System (ADS)

    Goetz, W.; Hecht, M. H.; Madsen, M. B.; Hviid, S. F.; Pike, T.; Staufer, U.; Leer, K.; Elmaarry, M.; Keller, H. U.; Markiewicz, W. J.

    2010-12-01

    The Optical Microscope (OM) onboard the Phoenix Mars Lander has returned high-resolution (4 μm/px) color images of soil particles at the landing site. Spectral information was acquired by illuminating the soil samples with four different types of Light Emitting Diodes (LEDs): UV (375 nm, weak emission at 705 nm), blue (B, 468 nm), green (G, 525 nm), and red (R, 636 nm) [Hecht et al., JGR 113, E00A22, 2008]. Analysis of images acquired in the visible channels (R, G, B) lead to the distinction of four different types of particles: (1) red fines (< 10 μm), (2) brown sand (20-100 μm), (3) black sand (20-100 μm), and (4) white fines (< 10 μm) [Goetz et al., JGR 115, E00E22, 2010]. Most particles (except white fines) were found to be substantially magnetic with a saturation magnetization in the range 0.5-2 A m2/kg. Different strategies were used to derive further information on these particles from the UV images. Their analysis is complicated due to the dual emission of the UV LEDs. Potential UV luminescent particles would be expected to belong to the brightest soil particle population, as dark (black) particles would auto-absorb luminescent emission. However, when taking into account the bright particles’ near-infrared reflectance (705 nm) that would be expected based on their known red reflectance (636 nm) analysis shows that particles with increasing brightness in the RGB color images do not become brighter in UV images. Statistical analysis of the UV images suggests that soil material as a whole does not show any measurable UV luminescence. Its potential quantum efficiency (QE) must be smaller than 0.01 %. An extensive search for particles that would shine up in the UV images was also unsuccessful. From these observations we conclude that the imaged soils do not show a measurable homogeneous level of luminescent emission. Furthermore we exclude the presence of strongly luminescent mineral grains in an (otherwise) non-luminescent soil matrix.

  10. Effective potentials in nonlinear polycrystals and quadrature formulae.

    PubMed

    Michel, Jean-Claude; Suquet, Pierre

    2017-08-01

    This study presents a family of estimates for effective potentials in nonlinear polycrystals. Noting that these potentials are given as averages, several quadrature formulae are investigated to express these integrals of nonlinear functions of local fields in terms of the moments of these fields. Two of these quadrature formulae reduce to known schemes, including a recent proposition (Ponte Castañeda 2015 Proc. R. Soc. A471, 20150665 (doi:10.1098/rspa.2015.0665)) obtained by completely different means. Other formulae are also reviewed that make use of statistical information on the fields beyond their first and second moments. These quadrature formulae are applied to the estimation of effective potentials in polycrystals governed by two potentials, by means of a reduced-order model proposed by the authors (non-uniform transformation field analysis). It is shown how the quadrature formulae improve on the tangent second-order approximation in porous crystals at high stress triaxiality. It is found that, in order to retrieve a satisfactory accuracy for highly nonlinear porous crystals under high stress triaxiality, a quadrature formula of higher order is required.

  11. The Fall 2000 and Fall 2001 SOHO-Ulysses Quadratures

    NASA Technical Reports Server (NTRS)

    Suess, S. T.; Poletto, G.

    2000-01-01

    SOHO-Ulysses quadrature occurs when the SOHO-Sun-Ulysses included angle is 90 degrees. It is only at such times that the same plasma leaving the Sun in the direction of Ulysses can first be remotely analyzed with SOHO instruments and then later be sampled in situ by Ulysses instruments. The quadratures in December 2000 and 2001 are of special significance because Ulysses will be near the south and north heliographic poles, respectively, and the solar cycle will be near sunspot maximum. Quadrature geometry is sometimes confusing and observations are influenced by solar rotation. The Fall 2000 and 2001 quadratures are more complex than usual because Ulysses is not in a true polar orbit and the orbital speed of Ulysses about the Sun is becoming comparable to the speed of SOHO about the Sun. In 2000 Ulysses will always be slightly behind the pole but will appear to hang over the pole for over two months because it is moving around the Sun in the same direction as SOHO. In 20001, Ulysses will be slightly in front of the pole so that its footpoint will be directly observable. Detailed plots will be shown of the relative positions of SOHO and Ulysses will their relative positions. In neither case is true quadrature actually achieved, but this works to the observers advantage in 2001.

  12. The Fall 2000 and Fall 2001 SOHO-Ulysses Quadratures

    NASA Technical Reports Server (NTRS)

    Suess, S. T.; Poletto, G.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    SOHO-Ulysses quadrature occurs when the SOHO-Sun-Ulysses included angle is 90 degrees. It is only at such times that the same plasma leaving the Sun in the direction of Ulysses can first be remotely analyzed with SOHO instruments and then later be sampled in situ by Ulysses instruments. The quadratures in December 2000 and 2001 are of special significance because Ulysses will be near the south and north heliographic poles, respectively, and the solar cycle will be near sunspot maximum. Quadrature geometry is sometimes confusing and observations are influenced by solar rotation. The Fall 2000 and 2001 quadratures are more complex than usual because Ulysses is not in a true polar orbit and the orbital speed of Ulysses about the Sun is becoming comparable to the speed of SOHO about the Sun. In 2000 Ulysses will always be slightly behind the pole but will appear to hang over the pole for over two months because it is moving around the Sun in the same direction as SOHO. In 2001 Ulysses will be slightly in front of the pole so that its footpoint will be directly observable. Detailed plots will be shown of the relative positions of SOHO and Ulysses will their relative positions. In neither case is true quadrature actually achieved, but this works to the observers advantage in 2001.

  13. Local detection efficiency of a NbN superconducting single photon detector explored by a scattering scanning near-field optical microscope.

    PubMed

    Wang, Qiang; Renema, Jelmer J; Engel, Andreas; van Exter, Martin P; de Dood, Michiel J A

    2015-09-21

    We propose an experiment to directly probe the local response of a superconducting single photon detector using a sharp metal tip in a scattering scanning near-field optical microscope. The optical absorption is obtained by simulating the tip-detector system, where the tip-detector is illuminated from the side, with the tip functioning as an optical antenna. The local detection efficiency is calculated by considering the recently introduced position-dependent threshold current in the detector. The calculated response for a 150 nm wide detector shows a peak close to the edge that can be spatially resolved with an estimated resolution of ∼ 20 nm, using a tip with parameters that are experimentally accessible.

  14. Fast algorithms for Quadrature by Expansion I: Globally valid expansions

    NASA Astrophysics Data System (ADS)

    Rachh, Manas; Klöckner, Andreas; O'Neil, Michael

    2017-09-01

    The use of integral equation methods for the efficient numerical solution of PDE boundary value problems requires two main tools: quadrature rules for the evaluation of layer potential integral operators with singular kernels, and fast algorithms for solving the resulting dense linear systems. Classically, these tools were developed separately. In this work, we present a unified numerical scheme based on coupling Quadrature by Expansion, a recent quadrature method, to a customized Fast Multipole Method (FMM) for the Helmholtz equation in two dimensions. The method allows the evaluation of layer potentials in linear-time complexity, anywhere in space, with a uniform, user-chosen level of accuracy as a black-box computational method. Providing this capability requires geometric and algorithmic considerations beyond the needs of standard FMMs as well as careful consideration of the accuracy of multipole translations. We illustrate the speed and accuracy of our method with various numerical examples.

  15. Kinetic Plasma Simulation Using a Quadrature-based Moment Method

    NASA Astrophysics Data System (ADS)

    Larson, David J.

    2008-11-01

    The recently developed quadrature-based moment method [Desjardins, Fox, and Villedieu, J. Comp. Phys. 227 (2008)] is an interesting alternative to standard Lagrangian particle simulations. The two-node quadrature formulation allows multiple flow velocities within a cell, thus correctly representing crossing particle trajectories and lower-order velocity moments without resorting to Lagrangian methods. Instead of following many particles per cell, the Eulerian transport equations are solved for selected moments of the kinetic equation. The moments are then inverted to obtain a discrete representation of the velocity distribution function. Potential advantages include reduced computational cost, elimination of statistical noise, and a simpler treatment of collisional effects. We present results obtained using the quadrature-based moment method applied to the Vlasov equation in simple one-dimensional electrostatic plasma simulations. In addition we explore the use of the moment inversion process in modeling collisional processes within the Complex Particle Kinetics framework.

  16. Imaging through turbulence with a quadrature-phase optical interferometer.

    PubMed

    Kern, Brian; Dimotakis, Paul E; Martin, Chris; Lang, Daniel B; Thessin, Rachel N

    2005-12-01

    We present an improved technique for imaging through turbulence at visible wavelengths using a rotation shearing pupil-plane interferometer, intended for astronomical and terrestrial imaging applications. While previous astronomical rotation shearing interferometers have made only visibility modulus measurements, this interferometer makes four simultaneous measurements on each interferometric baseline, with phase differences of pi/2 between each measurement, allowing complex visibility measurements (modulus and phase) across the entire input pupil in a single exposure. This technique offers excellent wavefront resolution, allowing operation at visible wavelengths on large apertures, is potentially immune to amplitude fluctuations (scintillation), and may offer superior calibration capabilities to other imaging techniques. The interferometer has been tested in the laboratory under weakly aberrating conditions and at Palomar Observatory under ordinary astronomical observing conditions. This research is based partly on observations obtained at the Hale Telescope.

  17. Tip-enhanced near-field optical microscope with side-on and ATR-mode sample excitation for super-resolution Raman imaging of surfaces

    NASA Astrophysics Data System (ADS)

    Heilman, A. L.; Gordon, M. J.

    2016-06-01

    A tip-enhanced near-field optical microscope with side-on and attenuated total reflectance (ATR) excitation and collection is described and used to demonstrate sub-diffraction-limited (super-resolution) optical and chemical characterization of surfaces. ATR illumination is combined with an Au optical antenna tip to show that (i) the tip can quantitatively transduce the optical near-field (evanescent waves) above the surface by scattering photons into the far-field, (ii) the ATR geometry enables excitation and characterization of surface plasmon polaritons (SPPs), whose associated optical fields are shown to enhance Raman scattering from a thin layer of copper phthalocyanine (CuPc), and (iii) SPPs can be used to plasmonically excite the tip for super-resolution chemical imaging of patterned CuPc via tip-enhanced Raman spectroscopy (TERS). ATR-illumination TERS is also quantitatively compared with the more conventional side-on illumination scheme. In both cases, spatial resolution was better than 40 nm and tip on/tip off Raman enhancement factors were >6500. Furthermore, ATR illumination was shown to provide similar Raman signal levels at lower "effective" pump powers due to additional optical energy delivered by SPPs to the active region in the tip-surface gap.

  18. Tip-enhanced near-field optical microscope with side-on and ATR-mode sample excitation for super-resolution Raman imaging of surfaces

    SciTech Connect

    Heilman, A. L.; Gordon, M. J.

    2016-06-14

    A tip-enhanced near-field optical microscope with side-on and attenuated total reflectance (ATR) excitation and collection is described and used to demonstrate sub-diffraction-limited (super-resolution) optical and chemical characterization of surfaces. ATR illumination is combined with an Au optical antenna tip to show that (i) the tip can quantitatively transduce the optical near-field (evanescent waves) above the surface by scattering photons into the far-field, (ii) the ATR geometry enables excitation and characterization of surface plasmon polaritons (SPPs), whose associated optical fields are shown to enhance Raman scattering from a thin layer of copper phthalocyanine (CuPc), and (iii) SPPs can be used to plasmonically excite the tip for super-resolution chemical imaging of patterned CuPc via tip-enhanced Raman spectroscopy (TERS). ATR-illumination TERS is also quantitatively compared with the more conventional side-on illumination scheme. In both cases, spatial resolution was better than 40 nm and tip on/tip off Raman enhancement factors were >6500. Furthermore, ATR illumination was shown to provide similar Raman signal levels at lower “effective” pump powers due to additional optical energy delivered by SPPs to the active region in the tip-surface gap.

  19. The connective tissue and glial framework in the optic nerve head of the normal human eye: light and scanning electron microscopic studies.

    PubMed

    Oyama, Tokuhide; Abe, Haruki; Ushiki, Tatsuo

    2006-12-01

    The arrangement of connective tissue components (i.e., collagen, reticular, and elastic fibers) and glial elements in the optic nerve head of the human eye was investigated by the combined use of light microscopy and scanning electron microscopy (SEM). Light-microscopically, the optic nerve head could be subdivided into four parts from the different arrangements of the connective tissue framework: a surface nerve fiber layer, and prelaminar, laminar, and postlaminar regions. The surface nerve fiber layer only possessed connective tissue elements around blood vessels. In the prelaminar region, collagen fibrils, together with delicate elastic fibers, formed thin interrupted sheaths for accommodating small nerve bundles. Immunohistochemistry for the glial fibrillary acidic protein (GFAP) showed that GFAP-positive cells formed columnar structures (i.e., glial columns), with round cell bodies piled up into layers. These glial columns were located in the fibrous sheaths of collagen fibrils and elastic fibers. In the laminar region, collagen fibrils and elastic fibers ran transversely to the optic nerve axis to form a thick membranous layer - the lamina cribrosa - which had numerous round openings for accommodating optic nerve fiber bundles. GFAP-positive cellular processes also ran transversely in association with collagen and elastin components. The postlaminar region had connective tissues which linked the lamina cribrosa with fibrous sheaths for accommodating nerve bundles in the extraocular optic nerve, where GFAP-positive cells acquired characteristics typical of fibrous astrocytes. These findings indicate that collagen fibrils, as a whole, form a continuous network which serves as a skeletal framework of the optic nerve head for protecting optic nerve fibers from mechanical stress as well as for sustaining blood vessels in the optic nerve. The lamina cribrosa containing elastic fibers are considered to be plastic against the mechanical force affected by elevation

  20. Discrete ordinate quadrature selection for reactor-based Eigenvalue problems

    SciTech Connect

    Jarrell, J. J.; Evans, T. M.; Davidson, G. G.

    2013-07-01

    In this paper we analyze the effect of various quadrature sets on the eigenvalues of several reactor-based problems, including a two-dimensional (2D) fuel pin, a 2D lattice of fuel pins, and a three-dimensional (3D) reactor core problem. While many quadrature sets have been applied to neutral particle discrete ordinate transport calculations, the Level Symmetric (LS) and the Gauss-Chebyshev product (GC) sets are the most widely used in production-level reactor simulations. Other quadrature sets, such as Quadruple Range (QR) sets, have been shown to be more accurate in shielding applications. In this paper, we compare the LS, GC, QR, and the recently developed linear-discontinuous finite element (LDFE) sets, as well as give a brief overview of other proposed quadrature sets. We show that, for a given number of angles, the QR sets are more accurate than the LS and GC in all types of reactor problems analyzed (2D and 3D). We also show that the LDFE sets are more accurate than the LS and GC sets for these problems. We conclude that, for problems where tens to hundreds of quadrature points (directions) per octant are appropriate, QR sets should regularly be used because they have similar integration properties as the LS and GC sets, have no noticeable impact on the speed of convergence of the solution when compared with other quadrature sets, and yield more accurate results. We note that, for very high-order scattering problems, the QR sets exactly integrate fewer angular flux moments over the unit sphere than the GC sets. The effects of those inexact integrations have yet to be analyzed. We also note that the LDFE sets only exactly integrate the zeroth and first angular flux moments. Pin power comparisons and analyses are not included in this paper and are left for future work. (authors)

  1. Estimation of the Breakup Cross-Sections in 6He + 12C Reaction Within High-Energy Approximation and Microscopic Optical Potential

    NASA Astrophysics Data System (ADS)

    Lukyanov, V. K.; Zemlyanaya, E. V.; Lukyanov, K. V.

    The breakup cross-sections in the reaction 6He + 12C are calculated at about 40 MeV/nucleon using the high-energy approximation (HEA) and with the help of microscopic optical potentials (OP) of interaction with the target nucleus 12C of the projectile nucleus fragments 4He and 2n. Considering the di-neutron h = 2n as a single particle the relative motion hα wave function is estimated so that to explain both the separation energy of h in 6He and the rms radius of the latter. The stripping and absorbtion total cross-sections are calculated and their sum is compared with the total reaction cross-section obtained within a double-folding microscopic OP for the 6He + 12C scattering. It is concluded that the breakup cross-sections contribute to about 50% of the total reaction cross-section.

  2. Bell's inequality for systems with quadrature phase coherence

    NASA Astrophysics Data System (ADS)

    Tan, S. M.; Holland, M. J.; Walls, D. F.

    1990-07-01

    We show that a violation of Bell's inequalities by quadrature phase measurements is not due to the interference of the two photons in a photon pair state. Rather the violation predicted by Grangier et al. for a parametric down-converter is due to the interference of the photon pair state with the vacuum. We propose new sources which violate the quadrature phase Bell's inequalities, including one which employs squeezed light and another which demonstrates the non-local properties of a single photon state.

  3. Digital holography with a quadrature phase-shifting interferometer.

    PubMed

    Kiire, Tomohiro; Nakadate, Suezou; Shibuya, Masato

    2009-03-01

    An alternative method for digital holography using a quadrature phase-shifting interferometer for high-speed measurement is presented. We show that it has image quality equal to the four-bucket method. In addition, it requires fewer imaging devices. Two quadrature phase-shifting fringe patterns are acquired in each state of an object changed temporally. The phase calculation method with these four fringe patterns gives the phase distribution of the hologram. This digital phase hologram is reconstructed to yield an object image by the Fresnel transform using digital convolutions with the fast Fourier transform algorithm. Verification results of simulations and experiments are given.

  4. Vibration analysis of structural elements using differential quadrature method

    PubMed Central

    Nassar, Mohamed; Matbuly, Mohamed S.; Ragb, Ola

    2012-01-01

    The method of differential quadrature is employed to analyze the free vibration of a cracked cantilever beam resting on elastic foundation. The beam is made of a functionally graded material and rests on a Winkler–Pasternak foundation. The crack action is simulated by a line spring model. Also, the differential quadrature method with a geometric mapping are applied to study the free vibration of irregular plates. The obtained results agreed with the previous studies in the literature. Further, a parametric study is introduced to investigate the effects of geometric and elastic characteristics of the problem on the natural frequencies. PMID:25685406

  5. Offset quadrature communications with decision-feedback carrier synchronization

    NASA Technical Reports Server (NTRS)

    Simon, M. K.; Smith, J. G.

    1974-01-01

    In order to accommodate a quadrature amplitude-shift-keyed (QASK) signal, Simon and Smith (1974) have modified the decision-feedback loop which tracks a quadrature phase-shift-keyed (QPSK). In the investigation reported approaches are considered to modify the loops in such a way that offset QASK signals can be tracked, giving attention to the special case of an offset QPSK. The development of the stochastic integro-differential equation of operation for a decision-feedback offset QASK loop is discussed along with the probability density function of the phase error process.

  6. Offset quadrature communications with decision-feedback carrier synchronization

    NASA Technical Reports Server (NTRS)

    Simon, M. K.; Smith, J. G.

    1974-01-01

    In order to accommodate a quadrature amplitude-shift-keyed (QASK) signal, Simon and Smith (1974) have modified the decision-feedback loop which tracks a quadrature phase-shift-keyed (QPSK). In the investigation reported approaches are considered to modify the loops in such a way that offset QASK signals can be tracked, giving attention to the special case of an offset QPSK. The development of the stochastic integro-differential equation of operation for a decision-feedback offset QASK loop is discussed along with the probability density function of the phase error process.

  7. A non-uniform grid for triangular differential quadrature

    NASA Astrophysics Data System (ADS)

    Zhong, HongZhi; Xu, Jia

    2016-12-01

    The triangular differential quadrature method based on a non-uniform grid is proposed in the paper. Explicit expressions of the non-uniform grid point coordinates are given and the weighting coefficients of the triangular differential quadrature method are determined with the aid of area coordinates. Two typical examples are presented to testify the effectiveness of the non-uniform grid. It is shown that rapid convergence is achieved under the non-uniform grid in comparison with those from the uniform grid with the same order of approximation.

  8. An Algorithm to Evaluate Imbalances of Quadrature Mixers

    NASA Astrophysics Data System (ADS)

    Asami, Koji; Arai, Michiaki

    It is essential, as bandwidths of wireless communications get wider, to evaluate the imbalances among quadrature mixer ports, in terms of carrier phase offset, IQ gain imbalance, and IQ skew. Because it is time consuming to separate skew, gain imbalance and carrier phase offset evaluation during test is often performed using a composite value, without separation of the imbalance factors. This paper describes an algorithm for enabling separation among quadrature mixer gain imbalance, carrier phase offset, and skew. Since the test time is reduced by the proposed method, it can be applied during high volume production testing.

  9. 21 CFR 884.6190 - Assisted reproductive microscopes and microscope accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction.... Assisted reproduction microscopes and microscope accessories (excluding microscope stage warmers, which are classified under assisted reproduction accessories) are optical instruments used to enlarge images of...

  10. 21 CFR 884.6190 - Assisted reproductive microscopes and microscope accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction.... Assisted reproduction microscopes and microscope accessories (excluding microscope stage warmers, which are classified under assisted reproduction accessories) are optical instruments used to enlarge images of...

  11. 21 CFR 884.6190 - Assisted reproductive microscopes and microscope accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction.... Assisted reproduction microscopes and microscope accessories (excluding microscope stage warmers, which are classified under assisted reproduction accessories) are optical instruments used to enlarge images of...

  12. 21 CFR 884.6190 - Assisted reproductive microscopes and microscope accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction.... Assisted reproduction microscopes and microscope accessories (excluding microscope stage warmers, which are classified under assisted reproduction accessories) are optical instruments used to enlarge images of...

  13. 21 CFR 884.6190 - Assisted reproductive microscopes and microscope accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction.... Assisted reproduction microscopes and microscope accessories (excluding microscope stage warmers, which are classified under assisted reproduction accessories) are optical instruments used to enlarge images of...

  14. Integration of a scanning ion conductance microscope into phase contrast optics and its application to the quantification of morphological parameters of selected cells.

    PubMed

    Mann, S A; Meyer, J W; Dietzel, I D

    2006-11-01

    We have previously described a pulse-mode scanning ion conductance microscope to investigate membrane surfaces and volume changes of individual cells in culture. We have now developed a miniaturized scanning headstage that enables us to select individual cells for recording under phase contrast optics, considerably improving the selection of individual cells for scanning as well as the positioning of the scanning frames with respect to the position of the cell somata. We show an application in which surfaces and volumes of somata and processes of cultured cells from the central nervous system were quantified separately.

  15. Preclinical evaluation and intraoperative human retinal imaging with a high-resolution microscope-integrated spectral domain optical coherence tomography device.

    PubMed

    Hahn, Paul; Migacz, Justin; O'Donnell, Rachelle; Day, Shelley; Lee, Annie; Lin, Phoebe; Vann, Robin; Kuo, Anthony; Fekrat, Sharon; Mruthyunjaya, Prithvi; Postel, Eric A; Izatt, Joseph A; Toth, Cynthia A

    2013-01-01

    The authors have recently developed a high-resolution microscope-integrated spectral domain optical coherence tomography (MIOCT) device designed to enable OCT acquisition simultaneous with surgical maneuvers. The purpose of this report is to describe translation of this device from preclinical testing into human intraoperative imaging. Before human imaging, surgical conditions were fully simulated for extensive preclinical MIOCT evaluation in a custom model eye system. Microscope-integrated spectral domain OCT images were then acquired in normal human volunteers and during vitreoretinal surgery in patients who consented to participate in a prospective institutional review board-approved study. Microscope-integrated spectral domain OCT images were obtained before and at pauses in surgical maneuvers and were compared based on predetermined diagnostic criteria to images obtained with a high-resolution spectral domain research handheld OCT system (HHOCT; Bioptigen, Inc) at the same time point. Cohorts of five consecutive patients were imaged. Successful end points were predefined, including ≥80% correlation in identification of pathology between MIOCT and HHOCT in ≥80% of the patients. Microscope-integrated spectral domain OCT was favorably evaluated by study surgeons and scrub nurses, all of whom responded that they would consider participating in human intraoperative imaging trials. The preclinical evaluation identified significant improvements that were made before MIOCT use during human surgery. The MIOCT transition into clinical human research was smooth. Microscope-integrated spectral domain OCT imaging in normal human volunteers demonstrated high resolution comparable to tabletop scanners. In the operating room, after an initial learning curve, surgeons successfully acquired human macular MIOCT images before and after surgical maneuvers. Microscope-integrated spectral domain OCT imaging confirmed preoperative diagnoses, such as full-thickness macular hole

  16. Anti-drift and auto-alignment mechanism for an astigmatic atomic force microscope system based on a digital versatile disk optical head.

    PubMed

    Hwu, E-T; Illers, H; Wang, W-M; Hwang, I-S; Jusko, L; Danzebrink, H-U

    2012-01-01

    In this work, an anti-drift and auto-alignment mechanism is applied to an astigmatic detection system (ADS)-based atomic force microscope (AFM) for drift compensation and cantilever alignment. The optical path of the ADS adopts a commercial digital versatile disc (DVD) optical head using the astigmatic focus error signal. The ADS-based astigmatic AFM is lightweight, compact size, low priced, and easy to use. Furthermore, the optical head is capable of measuring sub-atomic displacements of high-frequency AFM probes with a sub-micron laser spot (~570 nm, FWHM) and a high-working bandwidth (80 MHz). Nevertheless, conventional DVD optical heads suffer from signal drift problems. In a previous setup, signal drifts of even thousands of nanometers had been measured. With the anti-drift and auto-alignment mechanism, the signal drift is compensated by actuating a voice coil motor of the DVD optical head. A nearly zero signal drift was achieved. Additional benefits of this mechanism are automatic cantilever alignment and simplified design.

  17. From Lobatto Quadrature to the Euler Constant "e"

    ERIC Educational Resources Information Center

    Khattri, Sanjay Kumar

    2010-01-01

    Based on the Lobatto quadrature, we develop several new closed form approximations to the mathematical constant "e." For validating effectiveness of our approximations, a comparison of our results to the existing approximations is also presented. Another objective of our work is to inspire students to formulate other better approximations by using…

  18. Archimedes Quadrature of the Parabola: A Mechanical View

    ERIC Educational Resources Information Center

    Oster, Thomas J.

    2006-01-01

    In his famous quadrature of the parabola, Archimedes found the area of the region bounded by a parabola and a chord. His method was to fill the region with infinitely many triangles each of whose area he could calculate. In his solution, he stated, without proof, three preliminary propositions about parabolas that were known in his time, but are…

  19. Archimedes Quadrature of the Parabola: A Mechanical View

    ERIC Educational Resources Information Center

    Oster, Thomas J.

    2006-01-01

    In his famous quadrature of the parabola, Archimedes found the area of the region bounded by a parabola and a chord. His method was to fill the region with infinitely many triangles each of whose area he could calculate. In his solution, he stated, without proof, three preliminary propositions about parabolas that were known in his time, but are…

  20. Imaging with classical spherical diffraction gratings: the quadrature configuration.

    PubMed

    Prieto-Blanco, Xesús; Montero-Orille, Carlos; González-Núñez, Héctor; Dolores Mouriz, María; López Lago, Elena; de la Fuente, Raúl

    2009-11-01

    We review the theory of spherical diffraction gratings with regard to their imaging properties in off-plane arrangements. Our study is restricted to gratings with equally spaced grooves, and it is focused on the quadrature configuration, where the incident and diffraction planes are orthogonal to each other. We identify regions of low astigmatism and propose some monochromator mounts.

  1. 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.

  2. A compact "water-window" microscope with 60-nm spatial resolution based on a double stream gas-puff target and Fresnel zone plate optics

    NASA Astrophysics Data System (ADS)

    Wachulak, Przemyslaw; Torrisi, Alfio; Nawaz, Muhammad F.; Adjei, Daniel; Bartnik, Andrzej; Kostecki, Jerzy; Wegrzynski, Łukasz; Vondrová, Šárka; Turňová, Jana; Fok, Tomasz; Jančarek, Alexandr; Fiedorowicz, Henryk

    2015-05-01

    Radiation with shorter illumination wavelength allows for extension of the diffraction limit towards nanometer scale, which is a straightforward way to significantly improve a spatial resolution in photon based microscopes. Soft X-ray (SXR) radiation, from the so called "water window" spectral range, λ=2.3-4.4 nm, which is particularly suitable for biological imaging due to natural optical contrast, providing much better spatial resolution than one obtained with visible light microscopes. The high contrast is obtained because of selective absorption of radiation by carbon and water, being constituents of the biological samples. We present a desk-top system, capable of resolving 60 nm features in few seconds exposure time. We exploit the advantages of a compact, laser-plasma SXR source, based on a double stream nitrogen gas puff target, developed at the Institute of Optoelectronics, Military University of Technology. The source, emitting quasi-monochromatic, incoherent radiation, in the "water widow" spectral range at λ = 2.88 nm, is coupled with ellipsoidal, grazing incidence condenser and Fresnel zone plate objective. The construction of the microscope with some recent images of test and real samples will be presented and discussed.

  3. Modular multimodal swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography scan-head for surgical microscope-integrated and slit-lamp imaging

    NASA Astrophysics Data System (ADS)

    Malone, Joseph D.; Li, Jianwei D.; El-Haddad, Mohamed T.; Joos, Karen M.; Patel, Shriji N.; Tao, Yuankai K.

    2017-02-01

    Scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) enable noninvasive in vivo diagnostic imaging and provide complementary en face and depth-resolved visualization of ophthalmic structures, respectively. We previously demonstrated concurrent multimodal swept-source spectrally encoded scanning laser ophthalmoscopy and OCT (SS-SESLO-OCT) at 1060 nm using a swept-source and double clad fiber coupler. Here, we present system enhancements and novel designs for a modular SS-SESLO-OCT scan-head that can be coupled to ophthalmic surgical microscope-integrated and slit-lamp imaging optics. Multimodal SS-SESLO-OCT was demonstrated using a custom-built swept-source OCT engine with a 200 kHz 1060 nm source that was optically buffered for concurrent SESLO and OCT imaging at 100% duty cycle and 400 kHz sweep-rate. A shared optical relay and fast-axis galvanometer ensured inherent co-registration between SESLO and OCT field-of-views and concurrent acquisition of an en face SESLO image with each OCT cross-section. SESLO and OCT frames were acquired at 200 fps with 2560 x 2000 pix. (spectral x lateral). We show in vivo human ophthalmic imaging data using surgical microscope-integrated and slit-lamp imaging relays to demonstrate the utility of our SS-SESLO-OCT design. Our self-contained modular scan-head can be used for either intraoperative guidance or clinical diagnostics and reduces the complexity, cost, and maintenance required for clinical translation of these technologies. We believe concurrent multimodal SS-SESLO-OCT may benefit 1) intraoperative imaging by allowing for real-time surgical feedback, instrument tracking, and overlays of computationally extracted image-based surrogate biomarkers of disease, and 2) slit-lamp imaging by enabling aiming, image registration, and multi-field mosaicking.

  4. Provenance study through analysis of microstructural characteristics using an optical microscope and scanning electron microscopy for Goryeo celadon excavated from the seabed.

    PubMed

    Min-su, Han

    2013-08-01

    This paper aims at identifying the provenance of Goryeo celadons by understanding its microstructural characteristics, such as particles, blisters, forms and amount of pores, and the presence of crystal formation, bodies, and glazes and its boundary, using an optical microscope and scanning electron microscopy (SEM). The analysis of the reproduced samples shows that the glazed layer of the sherd fired at higher temperatures has lower viscosity and therefore it encourages the blisters to be combined together and the layer to become more transparent. In addition, the result showed that the vitrification and melting process of clay minerals such as feldspars and quartzs on the bodies was accelerated for those samples. To factor such characteristics of the microstructure and apply it to the sherds, the samples could be divided into six categories based on status, such as small particles with many small pores or mainly large and small circular pores in the bodies, only a limited number of varied sized blisters in the glazes, and a few blisters and needle-shaped crystals on the boundary surface. In conclusion, the analysis of the microstructural characteristics using an optical microscope and SEM have proven to be useful as a categorizing reference factor in a provenance study on Goryeo celadons.

  5. Environmental, scanning electron and optical microscope image analysis software for determining volume and occupied area of solid-state fermentation fungal cultures.

    PubMed

    Osma, Johann F; Toca-Herrera, José L; Rodríguez-Couto, Susana

    2011-01-01

    Here we propose a software for the estimation of the occupied area and volume of fungal cultures. This software was developed using a Matlab platform and allows analysis of high-definition images from optical, electronic or atomic force microscopes. In a first step, a single hypha grown on potato dextrose agar was monitored using optical microscopy to estimate the change in occupied area and volume. Weight measurements were carried out to compare them with the estimated volume, revealing a slight difference of less than 1.5%. Similarly, samples from two different solid-state fermentation cultures were analyzed using images from a scanning electron microscope (SEM) and an environmental SEM (ESEM). Occupied area and volume were calculated for both samples, and the results obtained were correlated with the dry weight of the cultures. The difference between the estimated volume ratio and the dry weight ratio of the two cultures showed a difference of 10%. Therefore, this software is a promising non-invasive technique to determine fungal biomass in solid-state cultures.

  6. [Microscopic colitis].

    PubMed

    Bohr, Johan

    2002-02-11

    Microscopic colitis is an umbrella term for a newly described group of colitides, belonging to the inflammatory bowel diseases, which are only diagnosable by microscopic evaluation of a macroscopically normal colon mucosa. Collagenous colitis and lymphocytic colitis are the most common of these colitides. Microscopic colitis is characterised clinically by chronic non-bloody watery diarrhoea. Crampy abdominal pain, nocturnal diarrhoea, urgency, and initial weight loss are usual. Concomitant diseases of autoimmune origin and arthralgia are commonly seen. Treatment of microscopic colitis follows the guidelines for treatment of other inflammatory bowel diseases, but a substantial part of the patients with microscopic colitis enter spontaneous remission after some years. A minor part, however, have very troublesome symptoms and are almost refractory to treatment. Microscopic colitis has apparently no malignant potential.

  7. Coherent detection of frequency-hopped quadrature modulations in the presence of jamming. II - QPR Class I modulation. [Quadrature Partial Response

    NASA Technical Reports Server (NTRS)

    Simon, M. K.

    1981-01-01

    This paper considers the performance of quadrature partial response (QPR) in the presence of jamming. Although a QPR system employs a single sample detector in its receiver, while quadrature amplitude shift keying (or quadrature phase shift keying) requires a matched-filter type of receiver, it is shown that the coherent detection performances of the two in the presence of the intentional jammer have definite similarities.

  8. Coherent detection of frequency-hopped quadrature modulations in the presence of jamming. II - QPR Class I modulation. [Quadrature Partial Response

    NASA Technical Reports Server (NTRS)

    Simon, M. K.

    1981-01-01

    This paper considers the performance of quadrature partial response (QPR) in the presence of jamming. Although a QPR system employs a single sample detector in its receiver, while quadrature amplitude shift keying (or quadrature phase shift keying) requires a matched-filter type of receiver, it is shown that the coherent detection performances of the two in the presence of the intentional jammer have definite similarities.

  9. Optical beam-induced current--investigations of integrated circuits using a laser scanning microscope with different excitation wavelengths

    NASA Astrophysics Data System (ADS)

    Bergner, Harald; Damm, Tobias

    1989-09-01

    A laser scanning microscope with an OBIC stage is used to investigate internal binary states of integrated circuits and diffusion parameters of the semiconductor material applying different laser wavelengths. The internal logical states of the circuit could be detected using blue and red laser radiation. Red and IR radiation are used to investigate the depth and location of doped wells. Applying three wavelengths it could be distinguished between surface and bulk recombination in the semiconductor material. The OBIC images of a CMOS inverter and a complete NOR-gate consisting of 10 transistors are analyzed in dependence on the logical input pattern.

  10. On the Unique Identification of the Polar Optical Kerr Effect with Microscopic Time-Reversal Symmetry Breaking

    NASA Astrophysics Data System (ADS)

    Fried, Alexander

    2014-03-01

    Over the past few decades, there has been an ongoing discussion regarding the choice of electromagnetic constitutive relations which correctly model linear media that exhibit natural optical activity, with most recent debate involving applications to optical phenomena in chiral superconductors and other gyrotropic media. In particular, is the controversy as to whether light incident upon naturally active materials will exhibit non-reciprocal polarization rotation in reflection, also known as the magneto-optical Kerr effect. A variety of constitutive relations have been postulated which describe the Electrodynamics within such materials, but only some of them predict this phenomena, while experimental investigations have similarly yielded mixed results. One such experiment uses a modified Sagnac Interferometer for high resolution and unique measurements of the Kerr effect and also has the property that it inherently tests for ``reciprocity,'' a metrological symmetry wherein the results of a measurement are the same as when an optical source and an optical detector are interchanged. We demonstrate theoretically and experimentally that the Sagnac Interferometer only measures time-reversal symemtry breaking and that gyrotropic materials can not give rise to a Kerr Effect.

  11. Microscopic, electrical and optical studies on InGaN/GaN quantum wells based LED devices

    SciTech Connect

    Mutta, Geeta Rani; Venturi, Giulia; Castaldini, Antonio; Cavallini, Anna

    2014-02-21

    We report here on the micro structural, electronic and optical properties of a GaN-based InGaN/GaN MQW LED grown by the MOVPE method. The present study shows that the threading dislocations present in these LED structures are terminated as V pits at the surface and have an impact on the electrical and optical activity of these devices. It has been pointed that these dislocations were of edge, screw and mixed types. EBIC maps suggest that the electrically active defects are screw and mixed dislocations and behave as nonradiative recombinant centres.

  12. The use of optical microscope equipped with multispectral detector to distinguish different types of acute lymphoblastic leukemia

    NASA Astrophysics Data System (ADS)

    Pronichev, A. N.; Polyakov, E. V.; Tupitsyn, N. N.; Frenkel, M. A.; Mozhenkova, A. V.

    2017-01-01

    The article describes the use of a computer optical microscopy with multispectral camera to characterize the texture of blasts bone marrow of patients with different variants of acute lymphoblastic leukemia: B- and T- types. Specific characteristics of the chromatin of the nuclei of blasts for different types of acute lymphoblastic leukemia were obtained.

  13. A hybrid high-speed atomic force-optical microscope for visualizing single membrane proteins on eukaryotic cells

    NASA Astrophysics Data System (ADS)

    Colom, Adai; Casuso, Ignacio; Rico, Felix; Scheuring, Simon

    2013-07-01

    High-speed atomic force microscopy is a powerful tool for studying structure and dynamics of proteins. So far, however, high-speed atomic force microscopy was restricted to well-controlled molecular systems of purified proteins. Here we integrate an optical microscopy path into high-speed atomic force microscopy, allowing bright field and fluorescence microscopy, without loss of high-speed atomic force microscopy performance. This hybrid high-speed atomic force microscopy/optical microscopy setup allows positioning of the high-speed atomic force microscopy tip with high spatial precision on an optically identified zone of interest on cells. We present movies at 960 ms per frame displaying aquaporin-0 array and single molecule dynamics in the plasma membrane of intact eye lens cells. This hybrid setup allows high-speed atomic force microscopy imaging on cells about 1,000 times faster than conventional atomic force microscopy/optical microscopy setups, and allows first time visualization of unlabelled membrane proteins on a eukaryotic cell under physiological conditions. This development advances high-speed atomic force microscopy from molecular to cell biology to analyse cellular processes at the membrane such as signalling, infection, transport and diffusion.

  14. Quadrature-based lattice Boltzmann model for relativistic flows

    NASA Astrophysics Data System (ADS)

    Blaga, Robert; Ambruş, Victor E.

    2017-01-01

    A quadrature-based finite-difference lattice Boltzmann model is developed that is suitable for simulating relativistic flows of massless particles. We briefly review the relativistc Boltzmann equation and present our model. The quadrature is constructed such that the stress-energy tensor is obtained as a second order moment of the distribution function. The results obtained with our model are presented for a particular instance of the Riemann problem (the Sod shock tube). We show that the model is able to accurately capture the behavior across the whole domain of relaxation times, from the hydrodynamic to the ballistic regime. The property of the model of being extendable to arbitrarily high orders is shown to be paramount for the recovery of the analytical result in the ballistic regime.

  15. Amplitude-weighted quadrature phase shift keying using SAW technology

    NASA Astrophysics Data System (ADS)

    Belkerdid, M. A.; Malocha, D. C.

    1985-09-01

    Surface acoustic wave (SAW) convolvers are capable of performing programmable matched filtering with the desirable properties of large processing gain, good dynamic range, broad bandwidth, small size and weight, and low power requirements. Equally powerful are the SAW-based modulators, which produce the desired pseudo-random code sequence for secure transmission in a spread-spectrum system. The SAW filter provides precise reproducible pulse shaping of the coded waveform with the same advantages of the convolver. It is very important as spectrum space becomes more crowded to optimize the spectral efficiency of transmitted information. Quadrature phase (QPSK) and minimum phase shift keying (MSK) are the two more popular quadrature modulation schemes. A new modulation technique that is composed of several amplitude-weighted QPSK signals (AWQPSK) and exhibits better bandwidth efficiency than OPSK or MSK is introduced. System analysis and performance parameters are presented for evaluation. A SAW modulator implementation is discussed and proposed.

  16. IQ quadrature demodulation algorithm used in heterodyne detection

    NASA Astrophysics Data System (ADS)

    Wang, Chunhui; Qu, Yang; Tang, Yajun Pang Tiantian

    2015-09-01

    In order to obtain better detection results of heterodyne, we used phase IQ quadrature demodulation algorithm to process the data which detected by laser heterodyne. Based on laser heterodyne interferometer, processing the data in the interferometer phase IQ quadrature demodulation algorithm from the signal to noise ratio, sampling rate, sampling rate, filter order and cutoff frequency, verify the effects of these system parameters to the phase precision, and choose the best parameters to obtain a better phase precision through experiment as: the signal to noise ratio is 25 dB, the IF signal frequency is 98.3 MHz, 98.5 MHz, 99.1 MHz, 99.5 MHz and 100 MHz, the sampling rate is 512-2048, the cutoff frequency and order of the filter are 0.11 and 40, respectively.

  17. Extraction of quadrature phase information from multiple pulse NMR signals

    NASA Technical Reports Server (NTRS)

    Rhim, W.-K.; Burum, D. P.; Vaughan, R. W.

    1976-01-01

    A multiple pulse sequence (8-pulse sequence) used for high-resolution solid state NMR is analyzed with regard to the information available from each of the four wide sampling windows. It is demonstrated that full quadrature phase information can be obtained using only a single phase detector and that, for the commonly encountered situation where the spectral width is much less than the folding frequency, the signals from the various windows can be combined easily using standard complex Fourier transform software. An improvement in the signal-to-noise ratio equal to the square root of 3 is obtained over either standard single or quadrature phase detection schemes. Procedures for correcting spectral distortions are presented.

  18. Solar Wind Characteristics from SOHO-Sun-Ulysses Quadrature Observations

    NASA Technical Reports Server (NTRS)

    Poletto, Giannina; Suess, Steve T.; Six, N. Frank (Technical Monitor)

    2002-01-01

    Over the past few years, we have been running SOHO (Solar and Heliospheric Observatory)-Sun-Ulysses quadrature campaigns, aimed at comparing the plasma properties at coronal altitudes with plasma properties at interplanetary distances. Coronal plasma has been observed by SOHO experiments: mainly, we used LASCO (Large Angle and Spectrometric Coronagraph Experiment) data to understand the overall coronal configuration at the time of quadratures and analyzed SUMER (Solar Ultraviolet Measurements of Emitted Radiation), CDS (Coronal Diagnostic Spectrometer) and UVCS (Ultraviolet Coronagraph Spectrometer) data to derive its physical characteristics. At interplanetary distances, SWICS (Solar Wind Ion Composition Spectrometer) and SWOOPS (Solar Wind Observation over the Poles of the Sun) aboard Ulysses provided us with interplanetary plasma data. Here we report on results from some of the campaigns. We notice that, depending on the geometry of the quadrature, i.e. on whether the radial to Ulysses traverses the corona at high or low latitudes, we are able to study different kinds of solar wind. In particular, a comparison between low-latitude and high-latitude wind, allowed us to provide evidence for differences in the acceleration of polar, fast plasma and equatorial, slow plasma: the latter occurring at higher levels and through a more extended region than fast wind. These properties are shared by both the proton and heavy ions outflows. Quadrature observations may provide useful information also on coronal vs. in situ elemental composition. To this end, we analyzed spectra taken in the corona, at altitudes ranging between approx. 1.02 and 2.2 solar radii, and derived the abundances of a number of ions, including oxygen and iron. Values of the O/Fe ratio, at coronal levels, have been compared with measurements of this ratio made by SWICS at interplanetary distances. Our results are compared with previous findings and predictions from modeling efforts.

  19. Studies of porphyrin-containing specimens using an optical spectrometer connected to a confocal scanning laser microscope.

    PubMed

    Trepte, O; Rokahr, I; Andersson-Engels, S; Carlsson, K

    1994-12-01

    A spectrometer has been developed for use with a confocal scanning laser microscope. With this unit, spectral information from a single point or a user-defined region within the microscope specimen can be recorded. A glass prism is used to disperse the spectral components of the recorded light over a linear CCD photodiode array with 256 elements. A regulated cooling unit keeps the detector at 277 K, thereby allowing integration times of up to 60 s. The spectral resolving power, lambda/delta lambda, ranges from 350 at lambda = 400 nm to 100 at lambda = 700 nm. Since the entrance aperture of the spectrometer has the same size as the detector pinhole used during normal confocal scanning, the three-dimensional spatial resolution is equivalent to that of normal confocal scanning. Light from the specimen is deflected to the spectrometer by a solenoid controlled mirror, allowing fast and easy switching between normal confocal scanning and spectrometer readings. With this equipment, studies of rodent liver specimens containing porphyrins have been made. The subcellular localization is of interest for the mechanisms of photodynamic therapy (PDT) of malignant tumours. Spectroscopic detection is necessary to distinguish the porphyrin signal from other fluorescent components in the specimen. Two different substances were administered to the tissue, Photofrin, a haematoporphyrin derivative (HPD) and delta-amino levulinic acid (ALA), a precursor to protoporphyrin IX and haem in the haem cycle. Both are substances under clinical trials for PDT of malignant tumours. Following administration of these compounds to the tissue, the potent photosensitizer and fluorescent compound Photofrin, or protoporphyrin IX, respectively, is accumulated.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. An Application of the Quadrature-Free Discontinuous Galerkin Method

    NASA Technical Reports Server (NTRS)

    Lockard, David P.; Atkins, Harold L.

    2000-01-01

    The process of generating a block-structured mesh with the smoothness required for high-accuracy schemes is still a time-consuming process often measured in weeks or months. Unstructured grids about complex geometries are more easily generated, and for this reason, methods using unstructured grids have gained favor for aerodynamic analyses. The discontinuous Galerkin (DG) method is a compact finite-element projection method that provides a practical framework for the development of a high-order method using unstructured grids. Higher-order accuracy is obtained by representing the solution as a high-degree polynomial whose time evolution is governed by a local Galerkin projection. The traditional implementation of the discontinuous Galerkin uses quadrature for the evaluation of the integral projections and is prohibitively expensive. Atkins and Shu introduced the quadrature-free formulation in which the integrals are evaluated a-priori and exactly for a similarity element. The approach has been demonstrated to possess the accuracy required for acoustics even in cases where the grid is not smooth. Other issues such as boundary conditions and the treatment of non-linear fluxes have also been studied in earlier work This paper describes the application of the quadrature-free discontinuous Galerkin method to a two-dimensional shear layer problem. First, a brief description of the method is given. Next, the problem is described and the solution is presented. Finally, the resources required to perform the calculations are given.

  1. Thin-plate spline quadrature of geodetic integrals

    NASA Technical Reports Server (NTRS)

    Vangysen, Herman

    1989-01-01

    Thin-plate spline functions (known for their flexibility and fidelity in representing experimental data) are especially well-suited for the numerical integration of geodetic integrals in the area where the integration is most sensitive to the data, i.e., in the immediate vicinity of the evaluation point. Spline quadrature rules are derived for the contribution of a circular innermost zone to Stoke's formula, to the formulae of Vening Meinesz, and to the recursively evaluated operator L(n) in the analytical continuation solution of Molodensky's problem. These rules are exact for interpolating thin-plate splines. In cases where the integration data are distributed irregularly, a system of linear equations needs to be solved for the quadrature coefficients. Formulae are given for the terms appearing in these equations. In case the data are regularly distributed, the coefficients may be determined once-and-for-all. Examples are given of some fixed-point rules. With such rules successive evaluation, within a circular disk, of the terms in Molodensky's series becomes relatively easy. The spline quadrature technique presented complements other techniques such as ring integration for intermediate integration zones.

  2. An Application of the Quadrature-Free Discontinuous Galerkin Method

    NASA Technical Reports Server (NTRS)

    Lockard, David P.; Atkins, Harold L.

    2000-01-01

    The process of generating a block-structured mesh with the smoothness required for high-accuracy schemes is still a time-consuming process often measured in weeks or months. Unstructured grids about complex geometries are more easily generated, and for this reason, methods using unstructured grids have gained favor for aerodynamic analyses. The discontinuous Galerkin (DG) method is a compact finite-element projection method that provides a practical framework for the development of a high-order method using unstructured grids. Higher-order accuracy is obtained by representing the solution as a high-degree polynomial whose time evolution is governed by a local Galerkin projection. The traditional implementation of the discontinuous Galerkin uses quadrature for the evaluation of the integral projections and is prohibitively expensive. Atkins and Shu introduced the quadrature-free formulation in which the integrals are evaluated a-priori and exactly for a similarity element. The approach has been demonstrated to possess the accuracy required for acoustics even in cases where the grid is not smooth. Other issues such as boundary conditions and the treatment of non-linear fluxes have also been studied in earlier work This paper describes the application of the quadrature-free discontinuous Galerkin method to a two-dimensional shear layer problem. First, a brief description of the method is given. Next, the problem is described and the solution is presented. Finally, the resources required to perform the calculations are given.

  3. Testing the Empirical Shock Arrival Model Using Quadrature Observations

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.; Makela, P.; Xie, H.; Yashiro, S.

    2013-01-01

    The empirical shock arrival (ESA) model was developed based on quadrature data from Helios (in situ) and P-78 (remote sensing) to predict the Sun-Earth travel time of coronal mass ejections (CMEs). The ESA model requires earthward CME speed as input, which is not directly measurable from coronagraphs along the Sun-Earth line. The Solar Terrestrial Relations Observatory (STEREO) and the Solar and Heliospheric Observatory (SOHO) were in quadrature during 20102012, so the speeds of Earth-directed CMEs were observed with minimal projection effects. We identified a set of 20 full halo CMEs in the field of view of SOHO that were also observed in quadrature by STEREO. We used the earthward speed from STEREO measurements as input to the ESA model and compared the resulting travel times with the observed ones from L1 monitors. We find that the model predicts the CME travel time within about 7.3 h, which is similar to the predictions by the ENLIL model. We also find that CME-CME and CME-coronal hole interaction can lead to large deviations from model predictions.

  4. Testing the Empirical Shock Arrival Model Using Quadrature Observations

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.; Makela, P.; Xie, H.; Yashiro, S.

    2013-01-01

    The empirical shock arrival (ESA) model was developed based on quadrature data from Helios (in situ) and P-78 (remote sensing) to predict the Sun-Earth travel time of coronal mass ejections (CMEs). The ESA model requires earthward CME speed as input, which is not directly measurable from coronagraphs along the Sun-Earth line. The Solar Terrestrial Relations Observatory (STEREO) and the Solar and Heliospheric Observatory (SOHO) were in quadrature during 20102012, so the speeds of Earth-directed CMEs were observed with minimal projection effects. We identified a set of 20 full halo CMEs in the field of view of SOHO that were also observed in quadrature by STEREO. We used the earthward speed from STEREO measurements as input to the ESA model and compared the resulting travel times with the observed ones from L1 monitors. We find that the model predicts the CME travel time within about 7.3 h, which is similar to the predictions by the ENLIL model. We also find that CME-CME and CME-coronal hole interaction can lead to large deviations from model predictions.

  5. Statistical Quadrature Evolution for Continuous-Variable Quantum Key Distribution

    NASA Astrophysics Data System (ADS)

    Gyongyosi, Laszlo; Imre, Sandor

    2016-05-01

    We propose a statistical quadrature evolution (SQE) method for multicarrier continuous-variable quantum key distribution (CVQKD). A multicarrier CVQKD protocol utilizes Gaussian subcarrier quantum continuous variables (CV) for information transmission. The SQE framework provides a minimal error estimate of the quadratures of the CV quantum states from the discrete, measured noisy subcarrier variables. We define a method for the statistical modeling and processing of noisy Gaussian subcarrier quadratures. We introduce the terms statistical secret key rate and statistical private classical information, which quantities are derived purely by the statistical functions of our method. We prove the secret key rate formulas for a multiple access multicarrier CVQKD. The framework can be established in an arbitrary CVQKD protocol and measurement setting, and are implementable by standard low-complexity statistical functions, which is particularly convenient for an experimental CVQKD scenario. This work was partially supported by the GOP-1.1.1-11-2012-0092 project sponsored by the EU and European Structural Fund, by the Hungarian Scientific Research Fund - OTKA K-112125, and by the COST Action MP1006.

  6. Quadrature two-dimensional correlation spectroscopy (Q-2DCOS)

    NASA Astrophysics Data System (ADS)

    Noda, Isao

    2016-11-01

    Quadrature 2D correlation spectroscopy (Q-2DCOS) is introduced. The technique incorporates the effect of the perturbation into the traditional 2DCOS analysis by building a multivariate model, merging the information of the perturbation variable and spectral responses. By employing factors which are 90° out of phase with each other, pertinent coincidental and sequential spectral intensity variations are adequately captured for the subsequent 2D correlation analysis. Almost complete replication of the original 2DCOS results based on such a simple rank 2 model of experimental spectra suggests that only the dominant spectral intensity variation patterns in combination with its quadrature counterpart seems to be utilized in 2DCOS analysis. Using the linear perturbation variable itself as the basis for generating the primary score vector is equivalent to the least squares fitting of a quadratic polynomial with spectral intensity variations. Q-2DCOS analysis may be displayed in terms of a graphical plot on a phase plane in the vector space, so that coincidental and sequential matching of the patterns of spectral intensity variations is represented simply by the phase angle difference between two vectors. Q-2DCOS analysis is closely related to other established ideas and practices in the 2D correlation spectroscopy field, such as dynamic 2D IR dichroism, PCA 2D, quadrature orthogonal signal correction (Q-OSC), and perturbation correlation moving window (PCMW) analyses.

  7. Ultrafast supercontinuum fiber-laser based pump-probe scanning magneto-optical Kerr effect microscope for the investigation of electron spin dynamics in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution

    SciTech Connect

    Henn, T.; Kiessling, T. Ossau, W.; Molenkamp, L. W.; Biermann, K.; Santos, P. V.

    2013-12-15

    We describe a two-color pump-probe scanning magneto-optical Kerr effect microscope which we have developed to investigate electron spin phenomena in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution. The key innovation of our microscope is the usage of an ultrafast “white light” supercontinuum fiber-laser source which provides access to the whole visible and near-infrared spectral range. Our Kerr microscope allows for the independent selection of the excitation and detection energy while avoiding the necessity to synchronize the pulse trains of two separate picosecond laser systems. The ability to independently tune the pump and probe wavelength enables the investigation of the influence of excitation energy on the optically induced electron spin dynamics in semiconductors. We demonstrate picosecond real-space imaging of the diffusive expansion of optically excited electron spin packets in a (110) GaAs quantum well sample to illustrate the capabilities of the instrument.

  8. A new microscope optics for laser dark-field illumination applied to high precision two dimensional measurement of specimen displacement.

    PubMed

    Noda, Naoki; Kamimura, Shinji

    2008-02-01

    With conventional light microscopy, precision in the measurement of the displacement of a specimen depends on the signal-to-noise ratio when we measure the light intensity of magnified images. This implies that, for the improvement of precision, getting brighter images and reducing background light noise are both inevitably required. For this purpose, we developed a new optics for laser dark-field illumination. For the microscopy, we used a laser beam and a pair of axicons (conical lenses) to get an optimal condition for dark-field observations. The optics was applied to measuring two dimensional microbead displacements with subnanometer precision. The bandwidth of our detection system overall was 10 kHz. Over most of this bandwidth, the observed noise level was as small as 0.1 nm/radicalHz.

  9. The microscopic (optical and SEM) examination of dental calculus deposits (DCD). Potential interest in forensic anthropology of a bio-archaeological method.

    PubMed

    Charlier, Philippe; Huynh-Charlier, Isabelle; Munoz, Olivia; Billard, Michel; Brun, Luc; de la Grandmaison, Geoffroy Lorin

    2010-07-01

    This article describes the potential interest in forensic anthropology of the microscopic analysis of dental calculus deposits (DCD), a calcified residue frequently found on the surface of teeth. Its sampling and analysis seem straightforward and relatively reproducible. Samples came from archaeological material (KHB-1 Ra's al-Khabbah and RH-5 Ra's al-Hamra, two Prehistoric graveyards located in the Sultanate of Oman, dated between the 5th and 4th millennium B.C.; Montenzio Vecchia, an Etruscan-Celtic necropolis from the north of Italy, dated between the 5th and 3rd century B.C.; body rests of Agnès Sorel, French royal mistress died in 1450 A.D.; skeleton of Pierre Hazard, French royal notary from the 15th century A.D.). Samples were studies by direct optical microscope (OM) or scanning electron microscopy (SEM). Many cytological, histological and elemental analyses were possible, producing precious data for the identification of these remains, the reconstitution of their alimentation and occupational habits, and propositions for manner of death. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  10. Second harmonic generation in a KNbO3 nanorod and its detection by using a near-field scanning optical microscope

    NASA Astrophysics Data System (ADS)

    Park, D. J.; Kang, P. G.; Jung, J. H.; Lee, H. H.; Choi, S. B.

    2016-04-01

    We report on an observation of second harmonic generation in an individual KNbO3 nanorod by using a near-field scanning optical microscope. The second harmonic is successfully generated by irradiating with a femtosecond laser having center wavelengths of 1200, 1100, and 972 nm. Such a second harmonic yield shows a clear dependence on the incident laser polarization, where maximum yield is obtained when the incident laser polarization is parallel to the long axis of an individual nanorod. A spatially-resolved second harmonic image shows a bright spot at the edge of the nanorod, which is attributed to the elaborated intensity of both fundamental laser light and second harmonic light inside the nanowire owing to cavity-mode formation.

  11. Direct evaluation of anisotropic carrier mobility in uniaxially aligned polymer semiconductor film by time-resolved microscopic optical second-harmonic generation measurement

    NASA Astrophysics Data System (ADS)

    Abe, Kentaro; Manaka, Takaaki; Iwamoto, Mitsumasa

    2017-01-01

    Mobility anisotropy in uniaxially-aligned fluorene co-polymer thin film was directly observed by using time-resolved microscopic optical second-harmonic generation (TRM-SHG) imaging. Main-chain orientation of fluorene co-polymer was determined by polarized absorption measurement, and the mobilities in the direction parallel and perpendicular to the main-chain were respectively estimated as 4.8× {{10}-3} cm2 Vs-1 and 1.2× {{10}-3} cm2 Vs-1 from the visualized carrier motion starting from a round-shape electrode. These results indicate that the mobility anisotropy of this sample was 4.0. Activation energy for each direction was also evaluated by the temperature dependence measurement as 117 and 94 meV, respectively. The TRM-SHG method enables us to estimate mobility and activation energy of the oriented polymer film in all directions at once.

  12. Integrated nonlinear optical imaging microscope for on-axis crystal detection and centering at a synchrotron beamline

    PubMed Central

    Madden, Jeremy T.; Toth, Scott J.; Dettmar, Christopher M.; Newman, Justin A.; Oglesbee, Robert A.; Hedderich, Hartmut G.; Everly, R. Michael; Becker, Michael; Ronau, Judith A.; Buchanan, Susan K.; Cherezov, Vadim; Morrow, Marie E.; Xu, Shenglan; Ferguson, Dale; Makarov, Oleg; Das, Chittaranjan; Fischetti, Robert; Simpson, Garth J.

    2013-01-01

    Nonlinear optical (NLO) instrumentation has been integrated with synchrotron X-ray diffraction (XRD) for combined single-platform analysis, initially targeting applications for automated crystal centering. Second-harmonic-generation microscopy and two-photon-excited ultraviolet fluorescence microscopy were evaluated for crystal detection and assessed by X-ray raster scanning. Two optical designs were constructed and characterized; one positioned downstream of the sample and one integrated into the upstream optical path of the diffractometer. Both instruments enabled protein crystal identification with integration times between 80 and 150 µs per pixel, representing a ∼103–104-fold reduction in the per-pixel exposure time relative to X-ray raster scanning. Quantitative centering and analysis of phenylalanine hydroxylase from Chromobacterium violaceum cPAH, Trichinella spiralis deubiquitinating enzyme TsUCH37, human κ-opioid receptor complex kOR-T4L produced in lipidic cubic phase (LCP), intimin prepared in LCP, and α-cellulose samples were performed by collecting multiple NLO images. The crystalline samples were characterized by single-crystal diffraction patterns, while α-cellulose was characterized by fiber diffraction. Good agreement was observed between the sample positions identified by NLO and XRD raster measurements for all samples studied. PMID:23765294

  13. A rapid optical clearing protocol using 2,2'-thiodiethanol for microscopic observation of fixed mouse brain.

    PubMed

    Aoyagi, Yuka; Kawakami, Ryosuke; Osanai, Hisayuki; Hibi, Terumasa; Nemoto, Tomomi

    2015-01-01

    Elucidation of neural circuit functions requires visualization of the fine structure of neurons in the inner regions of thick brain specimens. However, the tissue penetration depth of laser scanning microscopy is limited by light scattering and/or absorption by the tissue. Recently, several optical clearing reagents have been proposed for visualization in fixed specimens. However, they require complicated protocols or long treatment times. Here we report the effects of 2,2'-thiodiethanol (TDE) solutions as an optical clearing reagent for fixed mouse brains expressing a yellow fluorescent protein. Immersion of fixed brains in TDE solutions rapidly (within 30 min in the case of 400-µm-thick fixed brain slices) increased their transparency and enhanced the penetration depth in both confocal and two-photon microscopy. In addition, we succeeded in visualizing dendritic spines along single dendrites at deep positions in fixed thick brain slices. These results suggest that our proposed protocol using TDE solution is a rapid and useful method for optical clearing of fixed specimens expressing fluorescent proteins.

  14. Detection of interference phase by digital computation of quadrature signals in homodyne laser interferometry.

    PubMed

    Rerucha, Simon; Buchta, Zdenek; Sarbort, Martin; Lazar, Josef; Cip, Ondrej

    2012-10-19

    We have proposed an approach to the interference phase extraction in the homodyne laser interferometry. The method employs a series of computational steps to reconstruct the signals for quadrature detection from an interference signal from a non-polarising interferometer sampled by a simple photodetector. The complexity trade-off is the use of laser beam with frequency modulation capability. It is analytically derived and its validity and performance is experimentally verified. The method has proven to be a feasible alternative for the traditional homodyne detection since it performs with comparable accuracy, especially where the optical setup complexity is principal issue and the modulation of laser beam is not a heavy burden (e.g., in multi-axis sensor or laser diode based systems).

  15. Demodulation of quasi-quadrature interferometric signals for use in the totally implantable hearing aids

    PubMed Central

    Tomic, Milos C.; Djinovic, Zoran V.; Petricevic, Slobodan J.

    2017-01-01

    We propose and experimentally prove an algorithm for demodulation of interferometric signals, modified for use in a totally implantable hearing aid device. A fiber optic configuration, which generates two quasi-quadrature signals by a passive 3x3 coupler, for a non-contact detection of the middle ear ossicle vibration is employed. We simulated the ossicle vibration and large movements and demonstrated the effectiveness of the algorithm to compensate changes of the signal DC values and the phase shift introduced by the coupler. Applying the proposed algorithm we obtained the output signal stability better than 0.5 dB, and the system equivalent input noise of about 31 dB (A) SPL @ 1 kHz. PMID:28717576

  16. Transmission electron microscope CCD camera

    DOEpatents

    Downing, Kenneth H.

    1999-01-01

    In order to improve the performance of a CCD camera on a high voltage electron microscope, an electron decelerator is inserted between the microscope column and the CCD. This arrangement optimizes the interaction of the electron beam with the scintillator of the CCD camera while retaining optimization of the microscope optics and of the interaction of the beam with the specimen. Changing the electron beam energy between the specimen and camera allows both to be optimized.

  17. Direct observation on the Brownian coagulation of PSL particles through optical microscope in the regime near critical coagulation concentration (CCC).

    PubMed

    Fukasawa, Tomonori; Adachi, Yasuhisa

    2010-04-15

    Microscopic monitoring of floc structure, floc size distribution and the rate of coagulation was carried out for Brownian coagulation of PSL particles. Experiments were designed for the condition of salt concentration that is slightly below critical coagulation concentration (CCC). The density of the solvent was controlled by using deuterium oxide (D(2)O) to avoid sedimentation. Results are summarized as follows: (i) Near CCC, floc restructuring from the beginning stage of coagulation was evidenced, i.e., the ratio of linear triplet is found to be remarkably reduced as compared with the result obtained for the case of rapid coagulation which was implemented under sufficiently high salt concentration. (ii) The increase of fractal dimension from 1.8 in the case of rapid coagulation to 2.2 was confirmed by the analysis of mass balance using size distribution of flocs. This increment resulted in the decrease of effective excluded volume of flocs. (iii) The rate of coagulation was constant until later stage. This result contrasts to the result of rapid coagulation [T. Fukasawa, Y. Adachi, J. Colloid Interface Sci. 304 (2006) 115]. 2010 Elsevier Inc. All rights reserved.

  18. Two-wavelength quadrature multipoint detection of partial discharge in power transformers using fiber Fabry-Perot acoustic sensors

    NASA Astrophysics Data System (ADS)

    Dong, Bo; Han, Ming; Wang, Anbo

    2012-06-01

    A reliable and low-cost two-wavelength quadrature interrogating method has been developed to demodulate optical signals from diaphragm-based Fabry-Perot interferometric fiber optic sensors for multipoint partial discharge detection in power transformers. Commercial available fused-silica parts (a wafer, a fiber ferrule, and a mating sleeve) and a cleaved optical single mode fiber were bonded together to form an extrinsic Fabry-Perot acoustic sensor. Two lasers with center wavelengths separated by a quarter of the period of sensor interference fringes were used to probe acousticwave- induced diaphragm vibration. A coarse wavelength-division multiplexing (CWDM) add/drop multiplexer was used to separate the reflected two wavelengths before two photo detectors. Optical couplers were used to distribute mixed laser light to each sensor-detector module for multiplexing purpose. Sensor structure, detection system design and experiment results are presented.

  19. HIGH TEMPERATURE MICROSCOPE AND FURNACE

    DOEpatents

    Olson, D.M.

    1961-01-31

    A high-temperature microscope is offered. It has a reflecting optic situated above a molten specimen in a furnace and reflecting the image of the same downward through an inert optic member in the floor of the furnace, a plurality of spaced reflecting plane mirrors defining a reflecting path around the furnace, a standard microscope supported in the path of and forming the end terminus of the light path.

  20. Electron microscopic observations of Rb particles and pitting in 129Xe spin-exchange optical pumping cells

    NASA Astrophysics Data System (ADS)

    Flower, C.; Freeman, M. S.; Plue, M.; Driehuys, B.

    2017-07-01

    High-volume production of hyperpolarized 129Xe by spin-exchange optical pumping (SEOP) has historically fallen short of theoretical predictions. Recently, this shortfall was proposed to be caused by the formation of alkali metal clusters during optical pumping. However, this hypothesis has yet to be verified experimentally. Here, we seek to detect the presence of alkali particles using a combination of both transmission (TEM) and scanning (SEM) electron microscopy. From TEM studies, we observe the presence of particles exhibiting sizes ranging from approximately 0.2 to 1 μm and present at densities of order 10 s of particles per 100 square microns. Particle formation was more closely associated with extensive cell usage history than short-term ( ≈ 1 h) SEOP exposure. From the SEM studies, we observe pits on the cell surface. These pits are remarkably smooth, were frequently found adjacent to Rb particles, and located predominantly on the front face of the cells; they range in size from 1 to 5 μm. Together, these findings suggest that Rb particles do form during the SEOP process and at times can impart sufficient energy to locally alter the Pyrex surface.