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Sample records for optically controlled three-dimensional

  1. Three-dimensional shape optical measurement using constant gap control and error compensation

    SciTech Connect

    Park, Kyihwan; Kim, Sangyoo; Choi, Kyosoon

    2008-03-15

    The optical laser displacement sensor is widely used for noncontact measurement of the three-dimensional (3D) shape profile of the object surface. When the surface of an object has a slope variation, the sensor gain is proportionally varied according to that of the object surface. In order to solve the sensor gain variation problem, the constant gap control method is applied to adjust the gap to the nominal distance. Control error compensation is also proposed to cope with the situation even when the gap is not perfectly controlled to the nominal distance using an additional sensor attached to the actuator. 3D shape measurement applying the proposed constant gap control method shows better performances rather than the constant sensor height method.

  2. Design of hybrid optical tweezers system for controlled three-dimensional micromanipulation

    NASA Astrophysics Data System (ADS)

    Tanaka, Yoshio; Tsutsui, Shogo; Kitajima, Hiroyuki

    2013-04-01

    Three-dimensional (3D) micro/nano-manipulation using optical tweezers is a significant technique for various scientific fields ranging from biology to nanotechnology. For the dynamic handling of multiple/individual micro-objects in a true 3D working space, we present an improved hybrid optical tweezers system consisting of two multibeam techniques. These two techniques include the generalized phase contrast method with a spatial light modulator and the time-shared scanning method with a two-axis steering mirror and an electrically focus-tunable lens. Unlike our previously reported system that could only handle micro-objects in a two and half dimensional working space, the present system has high versatility for controlled manipulation of multiple micro-objects in a true 3D working space. The controlled rotation of five beads forming a pentagon, that of four beads forming a tetrahedron about arbitrary axes, and the fully automated assembly and subsequent 3D translation of micro-bead arrays are successfully demonstrated as part of the 3D manipulation experiment.

  3. Three-dimensional rearrangement of single atoms using actively controlled optical microtraps.

    PubMed

    Lee, Woojun; Kim, Hyosub; Ahn, Jaewook

    2016-05-02

    We propose and demonstrate three-dimensional rearrangements of single atoms. In experiments performed with single 87Rb atoms in optical microtraps actively controlled by a spatial light modulator, we demonstrate various dynamic rearrangements of up to N = 9 atoms including rotation, 2D vacancy filling, guiding, compactification, and 3D shuffling. With the capability of a phase-only Fourier mask to generate arbitrary shapes of the holographic microtraps, it was possible to place single atoms at arbitrary geometries of a few μm size and even continuously reconfigure them by conveying each atom. For this purpose, we loaded a series of computer-generated phase masks in the full frame rate of 60 Hz of the spatial light modulator, so the animation of phase mask transformed the holographic microtraps in real time, driving each atom along the assigned trajectory. Possible applications of this method of transformation of single atoms include preparation of scalable quantum platforms for quantum computation, quantum simulation, and quantum many-body physics.

  4. Three Dimensional Optic Tissue Culture and Process

    NASA Technical Reports Server (NTRS)

    OConnor, Kim C. (Inventor); Spaulding, Glenn F. (Inventor); Goodwin, Thomas J. (Inventor); Aten, Laurie A. (Inventor); Francis, Karen M. (Inventor); Caldwell, Delmar R. (Inventor); Prewett, Tacey L. (Inventor); Fitzgerald, Wendy S. (Inventor)

    1999-01-01

    A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioireactor at low shear conditions. The tissue forms as normal, functional tissue grows with tissue organization and extracellular matrix formation.

  5. Three dimensional optic tissue culture and process

    NASA Technical Reports Server (NTRS)

    Spaulding, Glenn F. (Inventor); Prewett, Tacey L. (Inventor); Goodwin, Thomas J. (Inventor); Francis, Karen M. (Inventor); Cardwell, Delmar R. (Inventor); Oconnor, Kim (Inventor); Fitzgerald, Wendy S. (Inventor); Aten, Laurie A. (Inventor)

    1994-01-01

    A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioreactor at low shear conditions. The tissue forms normal, functional tissue organization and extracellular matrix.

  6. Multiparallel Three-Dimensional Optical Microscopy

    NASA Technical Reports Server (NTRS)

    Nguyen, Lam K.; Price, Jeffrey H.; Kellner, Albert L.; Bravo-Zanoquera, Miguel

    2010-01-01

    Multiparallel three-dimensional optical microscopy is a method of forming an approximate three-dimensional image of a microscope sample as a collection of images from different depths through the sample. The imaging apparatus includes a single microscope plus an assembly of beam splitters and mirrors that divide the output of the microscope into multiple channels. An imaging array of photodetectors in each channel is located at a different distance along the optical path from the microscope, corresponding to a focal plane at a different depth within the sample. The optical path leading to each photodetector array also includes lenses to compensate for the variation of magnification with distance so that the images ultimately formed on all the photodetector arrays are of the same magnification. The use of optical components common to multiple channels in a simple geometry makes it possible to obtain high light-transmission efficiency with an optically and mechanically simple assembly. In addition, because images can be read out simultaneously from all the photodetector arrays, the apparatus can support three-dimensional imaging at a high scanning rate.

  7. Three-Dimensional Optical Coherence Tomography

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  8. Accurate core position control in polymer optical waveguides using the Mosquito method for three-dimensional optical wiring

    NASA Astrophysics Data System (ADS)

    Date, Kumi; Ishigure, Takaaki

    2017-02-01

    Polymer optical waveguides with graded-index (GI) circular cores are fabricated using the Mosquito method, in which the positions of parallel cores are accurately controlled. Such an accurate arrangement is of great importance for a high optical coupling efficiency with other optical components such as fiber ribbons. In the Mosquito method that we developed, a core monomer with a viscous liquid state is dispensed into another liquid state monomer for cladding via a syringe needle. Hence, the core positions are likely to shift during or after the dispensing process due to several factors. We investigate the factors, specifically affecting the core height. When the core and cladding monomers are selected appropriately, the effect of the gravity could be negligible, so the core height is maintained uniform, resulting in accurate core heights. The height variance is controlled in +/-2 micrometers for the 12 cores. Meanwhile, larger shift in the core height is observed when the needle-tip position is apart from the substrate surface. One of the possible reasons of the needle-tip height dependence is the asymmetric volume contraction during the monomer curing. We find a linear relationship between the original needle-tip height and the core-height observed. This relationship is implemented in the needle-scan program to stabilize the core height in different layers. Finally, the core heights are accurately controlled even if the cores are aligned on various heights. These results indicate that the Mosquito method enables to fabricate waveguides in which the cores are 3-dimensionally aligned with a high position accuracy.

  9. Three-dimensional winged nanocone optical antennas.

    PubMed

    Huttunen, Mikko J; Lindfors, Klas; Andriano, Domenico; Mäkitalo, Jouni; Bautista, Godofredo; Lippitz, Markus; Kauranen, Martti

    2014-06-15

    We introduce 3D optical antennas based on winged nanocones. The antennas support particle plasmon oscillations with current distributions that facilitate transformation of transverse far-field radiation to strong longitudinal local fields near the cone apices. We characterize the optical responses of the antennas by their extinction spectra and by second-harmonic generation microscopy with cylindrical vector beams. The results demonstrate a new 3D polarization-controllable optical antenna for applications in apertureless near-field microscopy, spectroscopy, and plasmonic sensing.

  10. Three-dimensional optical holography using a plasmonic metasurface

    PubMed Central

    Huang, Lingling; Chen, Xianzhong; Mühlenbernd, Holger; Zhang, Hao; Chen, Shumei; Bai, Benfeng; Tan, Qiaofeng; Jin, Guofan; Cheah, Kok-Wai; Qiu, Cheng-Wei; Li, Jensen; Zentgraf, Thomas; Zhang, Shuang

    2013-01-01

    Benefitting from the flexibility in engineering their optical response, metamaterials have been used to achieve control over the propagation of light to an unprecedented level, leading to highly unconventional and versatile optical functionalities compared with their natural counterparts. Recently, the emerging field of metasurfaces, which consist of a monolayer of photonic artificial atoms, has offered attractive functionalities for shaping wave fronts of light by introducing an abrupt interfacial phase discontinuity. Here we realize three-dimensional holography by using metasurfaces made of subwavelength metallic nanorods with spatially varying orientations. The phase discontinuity takes place when the helicity of incident circularly polarized light is reversed. As the phase can be continuously controlled in each subwavelength unit cell by the rod orientation, metasurfaces represent a new route towards high-resolution on-axis three-dimensional holograms with a wide field of view. In addition, the undesired effect of multiple diffraction orders usually accompanying holography is eliminated.

  11. Observation of three dimensional optical rogue waves through obstacles

    SciTech Connect

    Leonetti, Marco; Conti, Claudio

    2015-06-22

    We observe three-dimensional rogue waves in the speckle distribution of a spatially modulated optical beam. Light is transmitted beyond a partially reflecting obstacle generating optical rogue waves at a controlled position in the shadow of the barrier. When the barrier transmits only 0.07% of the input laser power, we observe the mostly localized event. These results demonstrate that an optimum amount of spatial non-homogeneity maximizes the probability of a gigantic event while the technique we exploit enables to control light behind a fully reflective wall.

  12. Observation of three dimensional optical rogue waves through obstacles

    NASA Astrophysics Data System (ADS)

    Leonetti, Marco; Conti, Claudio

    2015-06-01

    We observe three-dimensional rogue waves in the speckle distribution of a spatially modulated optical beam. Light is transmitted beyond a partially reflecting obstacle generating optical rogue waves at a controlled position in the shadow of the barrier. When the barrier transmits only 0.07% of the input laser power, we observe the mostly localized event. These results demonstrate that an optimum amount of spatial non-homogeneity maximizes the probability of a gigantic event while the technique we exploit enables to control light behind a fully reflective wall.

  13. Alignment-free three-dimensional optical metamaterials.

    PubMed

    Zhao, Yang; Shi, Jinwei; Sun, Liuyang; Li, Xiaoqin; Alù, Andrea

    2014-03-05

    Three-dimensional optical metamaterials based on multilayers typically rely on critical vertical alignment to achieve the desired functionality. Here the conditions under which three-dimensional metamaterials with different functionalities may be realized without constraints on alignment are analyzed and demonstrated experimentally. This study demonstrates that the release of alignment constraints for multilayered metamaterials is allowed, while their anomalous interaction with light is preserved. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Individual nanoantennas loaded with three-dimensional optical nanocircuits.

    PubMed

    Liu, Na; Wen, Fangfang; Zhao, Yang; Wang, Yumin; Nordlander, Peter; Halas, Naomi J; Alù, Andrea

    2013-01-09

    Nanoantennas are key optical components that bridge nanometer-scale optical signals to far-field, free-space radiation. In analogy to radio frequency antennas where tuning and impedance-matching are accomplished with lumped circuit elements, one could envision nanoantenna properties controlled by nanoscale, optical frequency circuit elements in which circuit operations are based on photons rather than electrons. A recent investigation of the infrared nanocircuits has demonstrated the filtering functionality using dielectric gratings. However, these two-dimensional prototypes have limited applicability in real-life devices. Here we experimentally demonstrate the first optical nanoscale circuits with fully three-dimensional lumped elements, which we use to tune and impedance-match a single optical dimer nanoantenna. We control the antenna resonance and impedance bandwidth using suitably designed loads with combinations of basic circuit elements: nanoscale capacitors, inductors, and resistors. Our results pave the way toward extending conventional circuit concepts into the visible domain for applications in data storage, wireless optical links, and related venues.

  15. Three dimensional time reversal optical tomography

    NASA Astrophysics Data System (ADS)

    Wu, Binlin; Cai, W.; Alrubaiee, M.; Xu, M.; Gayen, S. K.

    2011-03-01

    Time reversal optical tomography (TROT) approach is used to detect and locate absorptive targets embedded in a highly scattering turbid medium to assess its potential in breast cancer detection. TROT experimental arrangement uses multi-source probing and multi-detector signal acquisition and Multiple-Signal-Classification (MUSIC) algorithm for target location retrieval. Light transport from multiple sources through the intervening medium with embedded targets to the detectors is represented by a response matrix constructed using experimental data. A TR matrix is formed by multiplying the response matrix by its transpose. The eigenvectors with leading non-zero eigenvalues of the TR matrix correspond to embedded objects. The approach was used to: (a) obtain the location and spatial resolution of an absorptive target as a function of its axial position between the source and detector planes; and (b) study variation in spatial resolution of two targets at the same axial position but different lateral positions. The target(s) were glass sphere(s) of diameter ~9 mm filled with ink (absorber) embedded in a 60 mm-thick slab of Intralipid-20% suspension in water with an absorption coefficient μa ~ 0.003 mm-1 and a transport mean free path lt ~ 1 mm at 790 nm, which emulate the average values of those parameters for human breast tissue. The spatial resolution and accuracy of target location depended on axial position, and target contrast relative to the background. Both the targets could be resolved and located even when they were only 4-mm apart. The TROT approach is fast, accurate, and has the potential to be useful in breast cancer detection and localization.

  16. Designing a diffractive optical element for controlling the beam profile in a three-dimensional space using the simulated annealing algorithm

    NASA Astrophysics Data System (ADS)

    Liang, Wen-xi; Zhang, Jing-juan; Lü, Jun-feng; Liao, Rui

    2001-12-01

    We have designed a spatially quantized diffractive optical element (DOE) for controlling the beam profile in a three-dimensional space with the help of the simulated annealing (SA) algorithm. In this paper, we investigate the annealing schedule and the neighbourhood which are the deterministic parameters of the process that warrant the quality of the SA algorithm. The algorithm is employed to solve the discrete stochastic optimization problem of the design of a DOE. The objective function which constrains the optimization is also studied. The computed results demonstrate that the procedure of the algorithm converges stably to an optimal solution close to the global optimum with an acceptable computing time. The results meet the design requirement well and are applicable.

  17. Characterization of an Actively Controlled Three-Dimensional Turret Wake

    NASA Astrophysics Data System (ADS)

    Shea, Patrick; Glauser, Mark

    2012-11-01

    Three-dimensional turrets are commonly used for housing optical systems on airborne platforms. As bluff bodies, these geometries generate highly turbulent wakes that decrease the performance of the optical systems and the aircraft. The current experimental study looked to use dynamic suction in both open and closed-loop control configurations to actively control the turret wake. The flow field was characterized using dynamic pressure and stereoscopic PIV measurements in the wake of the turret. Results showed that the suction system was able to manipulate the wake region of the turret and could alter not only the spatial structure of the wake, but also the temporal behavior of the wake flow field. Closed-loop, feedback control techniques were used to determine a more optimal control input for the flow control. Similar control effects were seen for both the steady open-loop control case and the closed-loop feedback control configuration with a 45% reduction in the suction levels when comparing the closed-loop to the open-loop case. These results provide unique information regarding the development of the baseline three-dimensional wake and the wake with three different active flow control configurations.

  18. High-speed optical beam alignment based on a motion control technique for three-dimensional microelectromechanical systems optical switch modules

    NASA Astrophysics Data System (ADS)

    Mizukami, Masato; Yamaguchi, Joji; Nemoto, Naru

    2011-07-01

    For optical axis alignment when light deflection control of a MEMS mirror is done at high speed, we propose a method based on identifying the quadratic surface shape. The method uses information about the optical power monitored when the mirror is inclined to a small angle. It is shown that the search for maximum optical power is possible by using this method. We also designed a control system with a band-stop filter for resonance frequency to decrease residual vibration generated when the mirror is moved at high speed. We confirm that the searchable level of optical power can be improved.

  19. Ghost imaging for three-dimensional optical security

    SciTech Connect

    Chen, Wen Chen, Xudong

    2013-11-25

    Ghost imaging has become increasingly popular in quantum and optical application fields. Here, we report three-dimensional (3D) optical security using ghost imaging. The series of random phase-only masks are sparsified, which are further converted into particle-like distributions placed in 3D space. We show that either an optical or digital approach can be employed for the encoding. The results illustrate that a larger key space can be generated due to the application of 3D space compared with previous works.

  20. Three-dimensional theory of the magneto-optical trap

    SciTech Connect

    Prudnikov, O. N. Taichenachev, A. V.; Yudin, V. I.

    2015-04-15

    The kinetics of atoms in a three-dimensional magneto-optical trap (MOT) is considered. A three-dimensional MOT model has been constructed for an atom with the optical transition J{sub g} = 0 → J{sub e} = 1 (J{sub g,} {sub e} is the total angular momentum in the ground and excited states) in the semiclassical approximation by taking into account the influence of the relative phases of light fields on the kinetics of atoms. We show that the influence of the relative phases can be neglected only in the limit of low light field intensities. Generally, the choice of relative phases can have a strong influence on the kinetics of atoms in a MOT.

  1. Three-dimensional Gradient Index Optics Fabricated in Diffusive Photopolymers

    NASA Astrophysics Data System (ADS)

    Ye, Chunfang

    This thesis demonstrates three-dimensional gradient index (GRIN) optics fabricated in two diffusive photopolymers. These polymer optical components have localized gradient index structures, which are self-developed in diffusive photopolymers by introducing localized illuminations. Based on the sizes of the formed index structures, the photopolymer optics studied in this thesis fall into two categories: GRIN lens based optics and waveguide based optics. GRIN lenses and lens arrays with parabolic index profiles are created through Gaussian beam exposure, while GRIN lenses with arbitrary index profiles are created through a dual-axis galvo scanning system. Waveguide based optics, which include uniform waveguides, waveguide tapers, waveguides through thin optics and 900 sharp waveguide bends, are fabricated through direct-write lithography. Several quantitative characterization methods for the fabricated polymer optics are described. The index profiles of the GRIN lens based optics are quantitatively measured by a modified scanning transmission phase microscope and a Shack-Hartmann wavefront sensor. Three-dimensional mode profile characterization of the polymer waveguides is carried out through a novel polymer sample preparation procedure and an active mode imaging system. A single mode performance is confirmed for the fabricated waveguides. A loss measurement for the waveguides is also accomplished. An index formation model is developed for a diffusive polymer developed by Dr. McLeod's group, which provides a fundamental guidance for fabricating custom-design index structures in the polymer. A hybrid GRIN axicon lens is fabricated to significantly extend the depth of focus in an endoscopy OCT application. Potential applications of the fabricated polymer optics include hybrid integrated optical circuits. The diffusive photopolymer with self-development characteristics provides a platform to integrate various optoelectronic subcomponents in integrated optical circuits.

  2. Three-dimensional multifunctional optical coherence tomography for skin imaging

    NASA Astrophysics Data System (ADS)

    Li, En; Makita, Shuichi; Hong, Young-Joo; Kasaragod, Deepa; Sasaoka, Tomoko; Yamanari, Masahiro; Sugiyama, Satoshi; Yasuno, Yoshiaki

    2016-02-01

    Optical coherence tomography (OCT) visualizes cross-sectional microstructures of biological tissues. Recent developments of multifunctional OCT (MF-OCT) provides multiple optical contrasts which can reveal currently unknown tissue properties. In this contribution we demonstrate multifunctional OCT specially designed for dermatological investigation. And by utilizing it to measure four different body parts of in vivo human skin, three-dimensional scattering OCT, OCT angiography, polarization uniformity tomography, and local birefringence tomography images were obtained by a single scan. They respectively contrast the structure and morphology, vasculature, melanin content and collagen traits of the tissue.

  3. All-optical three-dimensional electron pulse compression

    NASA Astrophysics Data System (ADS)

    Jie Wong, Liang; Freelon, Byron; Rohwer, Timm; Gedik, Nuh; Johnson, Steven G.

    2015-01-01

    We propose an all-optical, three-dimensional electron pulse compression scheme in which Hermite-Gaussian optical modes are used to fashion a three-dimensional optical trap in the electron pulse’s rest frame. We show that the correct choices of optical incidence angles are necessary for optimal compression. We obtain analytical expressions for the net impulse imparted by Hermite-Gaussian free-space modes of arbitrary order. Although we focus on electrons, our theory applies to any charged particle and any particle with non-zero polarizability in the Rayleigh regime. We verify our theory numerically using exact solutions to Maxwell’s equations for first-order Hermite-Gaussian beams, demonstrating single-electron pulse compression factors of \\gt {{10}2} in both longitudinal and transverse dimensions with experimentally realizable optical pulses. The proposed scheme is useful in ultrafast electron imaging for both single- and multi-electron pulse compression, and as a means of circumventing temporal distortions in magnetic lenses when focusing ultrashort electron pulses. Other applications include the creation of flat electron beams and ultrashort electron bunches for coherent terahertz emission.

  4. Study of optical design of three-dimensional digital ophthalmoscopes.

    PubMed

    Fang, Yi-Chin; Yen, Chih-Ta; Chu, Chin-Hsien

    2015-10-01

    This study primarily involves using optical zoom structures to design a three-dimensional (3D) human-eye optical sensory system with infrared and visible light. According to experimental data on two-dimensional (2D) and 3D images, human-eye recognition of 3D images is substantially higher (approximately 13.182%) than that of 2D images. Thus, 3D images are more effective than 2D images when they are used at work or in high-recognition devices. In the optical system design, infrared and visible light wavebands were incorporated as light sources to perform simulations. The results can be used to facilitate the design of optical systems suitable for 3D digital ophthalmoscopes.

  5. Uncalibrated Three-Dimensional Microrobot Control

    DTIC Science & Technology

    2016-05-11

    microrobot to the target position without any prior knowledge of the system parameters such as electromagnetic field strengths, drag coefficients, or...intrinsic and extrinsic camera parameters. 15. SUBJECT TERMS Biomedical Microelectromechanical Systems, Robot Control, Electromagnetics , Visual...of the system parameters such as electromagnetic field strengths, drag coefficients, or intrinsic and extrinsic camera parameters. Keywords

  6. Three-dimensional optical-resolution photoacoustic microscopy.

    PubMed

    Hu, Song; Maslov, Konstantin; Wang, Lihong V

    2011-05-03

    Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As the mainstays of in vivo three-dimensional (3-D) optical microscopy, single-/multi-photon fluorescence microscopy and optical coherence tomography (OCT) have demonstrated their extraordinary sensitivities to fluorescence and optical scattering contrasts, respectively. However, the optical absorption contrast of biological tissues, which encodes essential physiological/pathological information, has not yet been assessable. The emergence of biomedical photoacoustics has led to a new branch of optical microscopy optical-resolution photoacoustic microscopy (OR-PAM), where the optical irradiation is focused to the diffraction limit to achieve cellular or even subcellular level lateral resolution. As a valuable complement to existing optical microscopy technologies, OR-PAM brings in at least two novelties. First and most importantly, OR-PAM detects optical absorption contrasts with extraordinary sensitivity (i.e., 100%). Combining OR-PAM with fluorescence microscopy or with optical-scattering-based OCT (or with both) provides comprehensive optical properties of biological tissues. Second, OR-PAM encodes optical absorption into acoustic waves, in contrast to the pure optical processes in fluorescence microscopy and OCT, and provides background-free detection. The acoustic detection in OR-PAM mitigates the impacts of optical scattering on signal degradation and naturally eliminates possible interferences (i.e., crosstalks) between excitation and detection, which is a common problem in fluorescence microscopy due to the overlap between the excitation and fluorescence spectra. Unique for optical absorption imaging, OR-PAM has demonstrated broad biomedical applications since its invention, including, but not limited to, neurology, ophthalmology, vascular biology, and dermatology. In this video, we teach the system

  7. Deterministic regularization of three-dimensional optical diffraction tomography

    PubMed Central

    Sung, Yongjin; Dasari, Ramachandra R.

    2012-01-01

    In this paper we discuss a deterministic regularization algorithm to handle the missing cone problem of three-dimensional optical diffraction tomography (ODT). The missing cone problem arises in most practical applications of ODT and is responsible for elongation of the reconstructed shape and underestimation of the value of the refractive index. By applying positivity and piecewise-smoothness constraints in an iterative reconstruction framework, we effectively suppress the missing cone artifact and recover sharp edges rounded out by the missing cone, and we significantly improve the accuracy of the predictions of the refractive index. We also show the noise handling capability of our algorithm in the reconstruction process. PMID:21811316

  8. The optical Anderson localization in three-dimensional percolation system

    NASA Astrophysics Data System (ADS)

    Burlak, G.; Martinez-Sánchez, E.

    2017-03-01

    We study the optical Anderson localization associated with the properties of three-dimensional (3D) disordered percolation system, where the percolating clusters are filled by active media composed by light noncoherent emitters. In such a non-uniformly spatial structure the radiating and scattering of field occur by incoherent way. We numerically study 3D field structures where the wave localization takes place and propose the criterion of field localization based on conception of a mean photon free path in such system. The analysis of a mean free path and the Inverse participation ratio (IPR) shows that the localization arises closely to the threshold of 3D percolation phase transition.

  9. Three-dimensional edge extraction in optical scanning holography

    NASA Astrophysics Data System (ADS)

    Zong, Yonghong; Zhou, Changhe; Ma, Jianyong; Jia, Wei; Wang, Jin

    2016-10-01

    Edge extraction has found applications in various image processing fields, such as in pattern recognition. In this paper, a new method is proposed for edge extraction of three-dimensional objects in optical scanning holography (OSH). Isotropic and anisotropic edge extraction of 3D objects is simulated using spiral phase plates in OSH operating in an incoherent mode. We propose to use a delta function and a spiral phase plate as the pupil functions to realize isotropic and anisotropic edge extraction. Our computer simulations show the capability of extracting the edges of a given 3D object by spiral phase filtering in OSH.

  10. Strongly Interacting Atom Lasers in Three-Dimensional Optical Lattices

    SciTech Connect

    Hen, Itay; Rigol, Marcos

    2010-10-29

    We show that the dynamical melting of a Mott insulator in a three-dimensional lattice leads to condensation at nonzero momenta, a phenomenon that can be used to generate strongly interacting atom lasers in optical lattices. For infinite on-site repulsion, the case considered here, the momenta at which bosons condense are determined analytically and found to have a simple dependence on the hopping amplitudes. The occupation of the condensates is shown to scale linearly with the total number of atoms in the initial Mott insulator. Our results are obtained by using a Gutzwiller-type mean-field approach, gauged against exact-diagonalization solutions of small systems.

  11. Carbon structures with three-dimensional periodicity at optical wavelengths

    PubMed

    Zakhidov; Baughman; Iqbal; Cui; Khayrullin; Dantas; Marti; Ralchenko

    1998-10-30

    Porous carbons that are three-dimensionally periodic on the scale of optical wavelengths were made by a synthesis route resembling the geological formation of natural opal. Porous silica opal crystals were sintered to form an intersphere interface through which the silica was removed after infiltration with carbon or a carbon precursor. The resulting porous carbons had different structures depending on synthesis conditions. Both diamond and glassy carbon inverse opals resulted from volume filling. Graphite inverse opals, comprising 40-angstrom-thick layers of graphite sheets tiled on spherical surfaces, were produced by surface templating. The carbon inverse opals provide examples of both dielectric and metallic optical photonic crystals. They strongly diffract light and may provide a route toward photonic band-gap materials.

  12. Three-dimensional orientation-unlimited polarization encryption by a single optically configured vectorial beam

    PubMed Central

    Li, Xiangping; Lan, Tzu-Hsiang; Tien, Chung-Hao; Gu, Min

    2012-01-01

    The interplay between light polarization and matter is the basis of many fundamental physical processes and applications. However, the electromagnetic wave nature of light in free space sets a fundamental limit on the three-dimensional polarization orientation of a light beam. Although a high numerical aperture objective can be used to bend the wavefront of a radially polarized beam to generate the longitudinal polarization state in the focal volume, the arbitrary three-dimensional polarization orientation of a beam has not been achieved yet. Here we present a novel technique for generating arbitrary three-dimensional polarization orientation by a single optically configured vectorial beam. As a consequence, by applying this technique to gold nanorods, orientation-unlimited polarization encryption with ultra-security is demonstrated. These results represent a new landmark of the orientation-unlimited three-dimensional polarization control of the light–matter interaction. PMID:22893122

  13. Three-dimensional optical metamaterial with a negative refractive index.

    PubMed

    Valentine, Jason; Zhang, Shuang; Zentgraf, Thomas; Ulin-Avila, Erick; Genov, Dentcho A; Bartal, Guy; Zhang, Xiang

    2008-09-18

    Metamaterials are artificially engineered structures that have properties, such as a negative refractive index, not attainable with naturally occurring materials. Negative-index metamaterials (NIMs) were first demonstrated for microwave frequencies, but it has been challenging to design NIMs for optical frequencies and they have so far been limited to optically thin samples because of significant fabrication challenges and strong energy dissipation in metals. Such thin structures are analogous to a monolayer of atoms, making it difficult to assign bulk properties such as the index of refraction. Negative refraction of surface plasmons was recently demonstrated but was confined to a two-dimensional waveguide. Three-dimensional (3D) optical metamaterials have come into focus recently, including the realization of negative refraction by using layered semiconductor metamaterials and a 3D magnetic metamaterial in the infrared frequencies; however, neither of these had a negative index of refraction. Here we report a 3D optical metamaterial having negative refractive index with a very high figure of merit of 3.5 (that is, low loss). This metamaterial is made of cascaded 'fishnet' structures, with a negative index existing over a broad spectral range. Moreover, it can readily be probed from free space, making it functional for optical devices. We construct a prism made of this optical NIM to demonstrate negative refractive index at optical frequencies, resulting unambiguously from the negative phase evolution of the wave propagating inside the metamaterial. Bulk optical metamaterials open up prospects for studies of 3D optical effects and applications associated with NIMs and zero-index materials such as reversed Doppler effect, superlenses, optical tunnelling devices, compact resonators and highly directional sources.

  14. Three dimensional imaging detector employing wavelength-shifting optical fibers

    DOEpatents

    Worstell, W.A.

    1997-02-04

    A novel detector element structure and method for its use is provided. In a preferred embodiment, one or more inorganic scintillating crystals are coupled through wavelength shifting optical fibers (WLSFs) to position sensitive photomultipliers (PS-PMTs). The superior detector configuration in accordance with this invention is designed for an array of applications in high spatial resolution gamma ray sensing with particular application to SPECT, PET and PVI imaging systems. The design provides better position resolution than prior art devices at a lower total cost. By employing wavelength shifting fibers (WLSFs), the sensor configuration of this invention can operate with a significant reduction in the number of photomultipliers and electronics channels, while potentially improving the resolution of the system by allowing three dimensional reconstruction of energy deposition positions. 11 figs.

  15. Three dimensional imaging detector employing wavelength-shifting optical fibers

    DOEpatents

    Worstell, William A.

    1997-01-01

    A novel detector element structure and method for its use is provided. In a preferred embodiment, one or more inorganic scintillating crystals are coupled through wavelength shifting optical fibers (WLSFs) to position sensitive photomultipliers (PS-PMTs). The superior detector configuration in accordance with this invention is designed for an array of applications in high spatial resolution gamma ray sensing with particular application to SPECT, PET and PVI imaging systems. The design provides better position resolution than prior art devices at a lower total cost. By employing wavelength shifting fibers (WLSFs), the sensor configuration of this invention can operate with a significant reduction in the number of photomultipliers and electronics channels, while potentially improving the resolution of the system by allowing three dimensional reconstruction of energy deposition positions.

  16. Three-dimensional spatial diffusion in optical molasses

    NASA Astrophysics Data System (ADS)

    Hodapp, T. W.; Gerz, C.; Furtlehner, C.; Westbrook, C. I.; Phillips, W. D.; Dalibard, J.

    1995-02-01

    We have studied the expansion of a small cloud of85Rb atoms in three-dimensional optical molasses (lin ⊥ lin and σ+ - σ- configurations) and observed diffusive motion. We determined the spatial-diffusion coefficients for various laser intensities and detunings, and compared them (in the case of lin ⊥ lin molasses) to values calculated from friction and momentum-diffusion coefficients of a one-dimensional (1D) theory of laser cooling. The predicted variations of the spatial-diffusion coefficient with laser intensity and detuning are in good qualitative agreement with the experimental data. We found that the minimal value observed experimentally, ≈ 6 × 10-4 cm2/s, lies within a factor of 3 of the 1D theoretical minimum, ≈, 26ħ/ M, where M is the atomic mass.

  17. Single cardiac cycle three-dimensional intracoronary optical coherence tomography.

    PubMed

    Kim, Tae Shik; Park, Hyun-Sang; Jang, Sun-Joo; Song, Joon Woo; Cho, Han Saem; Kim, Sunwon; Bouma, Brett E; Kim, Jin Won; Oh, Wang-Yuhl

    2016-12-01

    While high-speed intracoronary optical coherence tomography (OCT) provides three-dimensional (3D) visualization of coronary arteries in vivo, imaging speeds remain insufficient to avoid motion artifacts induced by heartbeat, limiting the clinical utility of OCT. In this paper, we demonstrate development of a high-speed intracoronary OCT system (frame rate: 500 frames/s, pullback speed: 100 mm/s) along with prospective electrocardiogram (ECG) triggering technology, which enabled volumetric imaging of long coronary segments within a single cardiac cycle (70 mm pullback in 0.7 s) with minimal cardiac motion artifact. This technology permitted detailed visualization of 3D architecture of the coronary arterial wall of a swine in vivo and fine structure of the implanted stent.

  18. Optical neuronal guidance in three-dimensional matrices.

    PubMed

    Graves, Catherine E; McAllister, Ryan G; Rosoff, William J; Urbach, Jeffrey S

    2009-05-15

    We demonstrate effective guidance of neurites extending from PC12 cells in a three-dimensional collagen matrix using a focused infrared laser. Processes can be redirected in an arbitrarily chosen direction in the imaging plane in approximately 30 min with an 80% success rate. In addition, the application of the laser beam significantly increases the rate of neurite outgrowth. These results extend previous observations on 2D coated glass coverslips. We find that the morphology of growth cones is very different in 3D than in 2D, and that this difference suggests that the filopodia play a key role in optical guidance. This powerful, flexible, non-contact guidance technique has potentially broad applications in tissues and engineered environments.

  19. Single cardiac cycle three-dimensional intracoronary optical coherence tomography

    PubMed Central

    Kim, Tae Shik; Park, Hyun-Sang; Jang, Sun-Joo; Song, Joon Woo; Cho, Han Saem; Kim, Sunwon; Bouma, Brett E.; Kim, Jin Won; Oh, Wang-Yuhl

    2016-01-01

    While high-speed intracoronary optical coherence tomography (OCT) provides three-dimensional (3D) visualization of coronary arteries in vivo, imaging speeds remain insufficient to avoid motion artifacts induced by heartbeat, limiting the clinical utility of OCT. In this paper, we demonstrate development of a high-speed intracoronary OCT system (frame rate: 500 frames/s, pullback speed: 100 mm/s) along with prospective electrocardiogram (ECG) triggering technology, which enabled volumetric imaging of long coronary segments within a single cardiac cycle (70 mm pullback in 0.7 s) with minimal cardiac motion artifact. This technology permitted detailed visualization of 3D architecture of the coronary arterial wall of a swine in vivo and fine structure of the implanted stent. PMID:28018710

  20. Three-dimensional multiway power dividers based on transformation optics

    PubMed Central

    Wu, Yong-Le; Zhuang, Zheng; Deng, Li; Liu, Yuan-An

    2016-01-01

    The two-dimensional (2D) or three-dimensional (3D) multiway power dividers based on transformation optical theory are proposed in this paper. It comprises of several nonisotropic mediums and one isotropic medium without any lumped and distributed elements. By using finite embedded coordinate transformations, the incident beam can be split and bent arbitrarily in order to achieve effective power division and transmission. In addition, the location of the split point can be employed to obtain unequal power dividers. Finally, several typical examples of the generalized power divider without limitation in 3D space are performed, which shows that the proposed power divider can implement required functions with arbitrary power division and arbitrary transmission paths. The excellent simulated results verify the novel design method for power dividers. PMID:27091541

  1. Intraoperative localization using a three-dimensional optical digitizer

    NASA Astrophysics Data System (ADS)

    Bucholz, Richard D.; Smith, Kurt R.; Henderson, Jaimie M.; McDurmont, Lee L.; Schulze, Dean W.

    1993-09-01

    Frame based stereotactic surgery allows the surgeon to precisely approach a predetermined target. Although useful for diagnostic and functional procedures, mechanical instruments fail to indicate position quickly during open craniotomy. We have developed a system employing an infrared optical digitizer to indicate position on either CT, MRI, or PET scans. The system consists of a base ring attached to the patient's head during surgery, hand held instruments of any type, a camera array, and a computer display. Light emitting diodes on the instruments and head ring are tracked by three linear CCDs suspended over the surgical field. The position of the surgical instrument relative to the patient's head is computed by a personal computer. Surgical position is indicated on an individual CT, MRI, or PET slice. A graphics workstation provides three dimensional display of position.

  2. Three-dimensional microfabrication through a multimode optical fiber.

    PubMed

    Morales-Delgado, Edgar E; Urio, Loic; Conkey, Donald B; Stasio, Nicolino; Psaltis, Demetri; Moser, Christophe

    2017-03-20

    3D printing based on additive manufacturing is an advanced manufacturing technique that allows the fabrication of arbitrary macroscopic and microscopic objects. Many 3D printing systems require large optical elements or nozzles in proximity to the built structure. This prevents their use in applications in which there is no direct access to the area where the objects have to be printed. Here, we demonstrate three-dimensional microfabrication based on two-photon polymerization (TPP) through an ultra-thin printing nozzle of 560 µm in diameter. Using wavefront shaping, femtosecond infrared pulses are focused and scanned through a multimode optical fiber (MMF) inside a photoresist that polymerizes via two-photon absorption. We show the construction of arbitrary 3D structures built with voxels of diameters down to 400 nm on the other side of the fiber. To our knowledge, this is the first demonstration of microfabrication through a multimode optical fiber. The proposed printing nozzle can reach and manufacture micro-structures in otherwise inaccessible areas through small apertures. Our work represents a new area which we refer to as endofabrication.

  3. Three-dimensional imaging technique using optical diffraction

    NASA Astrophysics Data System (ADS)

    Tan, Sheng; Hart, Douglas P.

    2002-02-01

    This paper presents a novel fast and simple technique to measure three-dimensional (3D) objects. An integrated 3D camera is built, which features a motorized off-axis rotating aperture. A regular spot pattern projection adds texture onto smooth 3D objects. When rotating, the off-axis aperture translates depth information into blurred image diameter. The displacement of each spot between two arbitrary aperture positions reveals depth. A pseudo- correlation algorithm based on optical diffraction is proposed to measure spot displacement fast and accurately. When subtracting two consecutive images of a roughly Gaussian-shaped displaced spot, the normalized subtraction intensity peak height is directly proportional to the spot displacement. The peak height to displacement calibration curve is specifically defined by optical parameters of the imaging system. Proper combination of off-axis aperture location and magnification ratio determines the size of the measurement range. Experiment observations show that the calibration curve is highly smooth and sensitive to the spot displacement at sub-pixel level. Real-time processing is possible with only order of image size arithmetic operations. The proposed technique holds potential for various industrial machine vision applications.

  4. Interpretation of optical three-dimensional coherent spectroscopy

    NASA Astrophysics Data System (ADS)

    Titze, Michael; Li, Hebin

    2017-09-01

    As an extension to powerful two-dimensional coherent spectroscopy, optical three-dimensional (3D) coherent spectroscopy has been experimentally implemented and found beneficial in studying various systems in physics and chemistry. A critical challenge is how to interpret 3D spectra and extract useful quantitative information, given the richness and complexity of 3D data. Here, we demonstrate how the information of a system's optical response is manifested in 3D spectra by theoretical simulations of a few representative examples including a homogeneous three-level V system, an inhomogeneous three-level V system, and an inhomogeneous three-level ladder system. These examples show that important parameters of the system can be extracted from the spectral pattern, peak positions, amplitudes, and line shapes. The method developed here can be used to analyze 3D spectra of more sophisticated systems which might be a generalization or combination of the three examples, contributing to develop a general approach for the interpretation of 3D spectra.

  5. Electroencephalographic (EEG) control of three-dimensional movement

    NASA Astrophysics Data System (ADS)

    McFarland, Dennis J.; Sarnacki, William A.; Wolpaw, Jonathan R.

    2010-06-01

    Brain-computer interfaces (BCIs) can use brain signals from the scalp (EEG), the cortical surface (ECoG), or within the cortex to restore movement control to people who are paralyzed. Like muscle-based skills, BCIs' use requires activity-dependent adaptations in the brain that maintain stable relationships between the person's intent and the signals that convey it. This study shows that humans can learn over a series of training sessions to use EEG for three-dimensional control. The responsible EEG features are focused topographically on the scalp and spectrally in specific frequency bands. People acquire simultaneous control of three independent signals (one for each dimension) and reach targets in a virtual three-dimensional space. Such BCI control in humans has not been reported previously. The results suggest that with further development noninvasive EEG-based BCIs might control the complex movements of robotic arms or neuroprostheses.

  6. Three-dimensional calibration targets for optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Gabriele Sandrian, Michelle; Tomlins, Pete; Woolliams, Peter; Rasakanthan, Janarthanan; Lee, Graham C.; Yang, Anna; Považay, Boris; Alex, Aneesh; Sugden, Kate; Drexler, Wolfgang

    2012-03-01

    The recent expansion of clinical applications for optical coherence tomography (OCT) is driving the development of approaches for consistent image acquisition. There is a simultaneous need for time-stable, easy-to-use imaging targets for calibration and standardization of OCT devices. We present calibration targets consisting of three-dimensional structures etched into nanoparticle-embedded resin. Spherical iron oxide nanoparticles with a predominant particle diameter of 400 nm were homogeneously dispersed in a two part polyurethane resin and allowed to harden overnight. These samples were then etched using a precision micromachining femtosecond laser with a center wavelength of 1026 nm, 100kHz repetition rate and 450 fs pulse duration. A series of lines in depth were etched, varying the percentage of inscription energy and speed of the translation stage moving the target with respect to the laser. Samples were imaged with a dual wavelength spectral-domain OCT system (λ=800nm, ▵λ~180nm, and λ=1325nm, ▵λ~100nm) and point-spread function of nanoparticles within the target was measured.

  7. Radiation dosimetry using three-dimensional optical random access memories

    NASA Technical Reports Server (NTRS)

    Moscovitch, M.; Phillips, G. W.

    2001-01-01

    Three-dimensional optical random access memories (3D ORAMs) are a new generation of high-density data storage devices. Binary information is stored and retrieved via a light induced reversible transformation of an ensemble of bistable photochromic molecules embedded in a polymer matrix. This paper describes the application of 3D ORAM materials to radiation dosimetry. It is shown both theoretically and experimentally, that ionizing radiation in the form of heavy charged particles is capable of changing the information originally stored on the ORAM material. The magnitude and spatial distribution of these changes are used as a measure of the absorbed dose, particle type and energy. The effects of exposure on 3D ORAM materials have been investigated for a variety of particle types and energies, including protons, alpha particles and 12C ions. The exposed materials are observed to fluoresce when exposed to laser light. The intensity and the depth of the fluorescence is dependent on the type and energy of the particle to which the materials were exposed. It is shown that these effects can be modeled using Monte Carlo calculations. The model provides a better understanding of the properties of these materials. which should prove useful for developing systems for charged particle and neutron dosimetry/detector applications. c2001 Published by Elsevier Science B.V.

  8. Three-Dimensional Reconstruction Optical System Using Shadows Triangulation

    NASA Astrophysics Data System (ADS)

    Barba, J. Leiner; Vargas, Q. Lorena; Torres, M. Cesar; Mattos, V. Lorenzo

    2008-04-01

    In this work is developed a three-dimensional reconstruction system using the Shades3D tool of the Matlab® Programming Language and materials of low cost, such as webcam camera, a stick, a weak structured lighting system composed by a desk lamp, and observation plane in which the object is located. The reconstruction is obtained through a triangulation process that is executed after acquiring a sequence of images of the scene with a shadow projected on the object; additionally an image filtering process is done for obtaining only the part of the scene that will be reconstructed. Previously, it is necessary to develop a calibration process for determining the internal camera geometric and optical characteristics (intrinsic parameters), and the 3D position and orientation of the camera frame relative to a certain world coordinate system (extrinsic parameters). The lamp and the stick are used to produce a shadow which scans the object; in this technique, it is not necessary to know the position of the light source, instead the triangulation is obtained using shadow plane produced by intersection between the stick and the illumination pattern. The webcam camera captures all images with the shadow scanning the object, and Shades3D tool processes all information taking into account captured images and calibration parameters. Likewise, this technique is evaluated in the reconstruction of parts of the human body and its application in the detection of external abnormalities and elaboration of prosthesis or implant.

  9. Radiation dosimetry using three-dimensional optical random access memories

    NASA Technical Reports Server (NTRS)

    Moscovitch, M.; Phillips, G. W.

    2001-01-01

    Three-dimensional optical random access memories (3D ORAMs) are a new generation of high-density data storage devices. Binary information is stored and retrieved via a light induced reversible transformation of an ensemble of bistable photochromic molecules embedded in a polymer matrix. This paper describes the application of 3D ORAM materials to radiation dosimetry. It is shown both theoretically and experimentally, that ionizing radiation in the form of heavy charged particles is capable of changing the information originally stored on the ORAM material. The magnitude and spatial distribution of these changes are used as a measure of the absorbed dose, particle type and energy. The effects of exposure on 3D ORAM materials have been investigated for a variety of particle types and energies, including protons, alpha particles and 12C ions. The exposed materials are observed to fluoresce when exposed to laser light. The intensity and the depth of the fluorescence is dependent on the type and energy of the particle to which the materials were exposed. It is shown that these effects can be modeled using Monte Carlo calculations. The model provides a better understanding of the properties of these materials. which should prove useful for developing systems for charged particle and neutron dosimetry/detector applications. c2001 Published by Elsevier Science B.V.

  10. Three dimensional tracking with misalignment between display and control axes

    NASA Technical Reports Server (NTRS)

    Ellis, Stephen R.; Tyler, Mitchell; Kim, Won S.; Stark, Lawrence

    1992-01-01

    Human operators confronted with misaligned display and control frames of reference performed three dimensional, pursuit tracking in virtual environment and virtual space simulations. Analysis of the components of the tracking errors in the perspective displays presenting virtual space showed that components of the error due to visual motor misalignment may be linearly separated from those associated with the mismatch between display and control coordinate systems. Tracking performance improved with several hours practice despite previous reports that such improvement did not take place.

  11. Three-dimensional control of Tetrahymena pyriformis using artificial magnetotaxis

    NASA Astrophysics Data System (ADS)

    Hyung Kim, Dal; Seung Soo Kim, Paul; Agung Julius, Anak; Jun Kim, Min

    2012-01-01

    We demonstrate three-dimensional control with the eukaryotic cell Tetrahymena pyriformis (T. pyriformis) using two sets of Helmholtz coils for xy-plane motion and a single electromagnet for z-direction motion. T. pyriformis is modified to have artificial magnetotaxis with internalized magnetite. To track the cell's z-axis position, intensity profiles of non-motile cells at varying distances from the focal plane are used. During vertical motion along the z-axis, the intensity difference is used to determine the position of the cell. The three-dimensional control of the live microorganism T. pyriformis as a cellular robot shows great potential for practical applications in microscale tasks, such as target transport and cell therapy.

  12. Terahertz (THz) Optical Parameters of Three-Dimensional (3-D) Printing Materials

    DTIC Science & Technology

    2017-03-01

    TECHNICAL REPORT RDMR-WD-16-62 TERAHERTZ (THZ) OPTICAL PARAMETERS OF THREE-DIMENSIONAL (3-D) PRINTING MATERIALS Martin...3. REPORT TYPE AND DATES COVERED Final 4. TITLE AND SUBTITLE Terahertz (THz) Optical Parameters of Three-Dimensional (3-D) Printing Materials ...spectral optical characteristics of bulk printing materials commonly used in 3-D printing. 14. SUBJECT TERMS Three-Dimensional (3-D) Printing

  13. Three dimensional laser microfabrication in diamond using a dual adaptive optics system.

    PubMed

    Simmonds, Richard D; Salter, Patrick S; Jesacher, Alexander; Booth, Martin J

    2011-11-21

    Femtosecond laser fabrication of controlled three dimensional structures deep in the bulk of diamond is facilitated by a dual adaptive optics system. A deformable mirror is used in parallel with a liquid crystal spatial light modulator to compensate the extreme aberrations caused by the refractive index mismatch between the diamond and the objective immersion medium. It is shown that aberration compensation is essential for the generation of controlled micron-scale features at depths greater than 200 μm, and the dual adaptive optics approach demonstrates increased fabrication efficiency relative to experiments using a single adaptive element. © 2011 Optical Society of America

  14. Synthesis and optical properties of three-dimensional porous core-shell nanoarchitectures.

    PubMed

    Qian, Li-Hua; Ding, Yi; Fujita, Takeshi; Chen, Ming-Wei

    2008-05-06

    Three-dimensional porous core-shell nanostructures consisting of gold skeletons and silver shells were fabricated by controllable electroless plating. Optical properties of the 3D nanocomposite with a heterogeneous interface exhibit a significant shell-thickness dependence. The porous core-shell structure with an optimized shell thickness of approximately 3-5 nm exhibits a considerable improvement in surface-enhanced Raman scattering. This study has important implications in the functionalization of nanoporous metals by surface modification.

  15. Three-dimensional ultrashort optical Airy beams in an inhomogeneous medium with carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zhukov, Alexander V.; Bouffanais, Roland; Belonenko, Mikhail B.; Dvuzhilov, Ilya S.

    2017-03-01

    In this Letter, we consider the problem of the dynamics of propagation of three-dimensional optical pulses (a.k.a. light bullets) with an Airy profile through a heterogeneous environment of carbon nanotubes. We show numerically that such beams exhibit sustained and stable propagation. Moreover, we demonstrate that by varying the density modulation period of the carbon nanotubes one can indirectly control the pulse velocity, which is a particularly valuable feature for the design and manufacturing of novel pulse delay devices.

  16. Three-dimensional acousto-optic spectrum analysis

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon; Metscher, Brian; Lesh, James R.

    1990-01-01

    A three-dimensional acoustooptic spectrum analyzer with subhertz resolution is demonstrated experimentally. The first and second dimensions are the two spatial dimensions of the output detector array, and the third dimension is time as sampled by the detector array frame rate. A superfine resolution of 0.12 Hz has been achieved.

  17. Controlling Random Lasing with Three-Dimensional Plasmonic Nanorod Metamaterials.

    PubMed

    Wang, Zhuoxian; Meng, Xiangeng; Choi, Seung Ho; Knitter, Sebastian; Kim, Young L; Cao, Hui; Shalaev, Vladimir M; Boltasseva, Alexandra

    2016-04-13

    Plasmonics has brought revolutionary advances to laser science by enabling deeply subwavelength nanolasers through surface plasmon amplification. However, the impact of plasmonics on other promising laser systems has so far remained elusive. Here, we present a class of random lasers enabled by three-dimensional plasmonic nanorod metamaterials. While dense metallic nanostructures are usually detrimental to laser performance due to absorption losses, here the lasing threshold keeps decreasing as the volume fraction of metal is increased up to ∼0.07. This is ∼460 times higher than the optimal volume fraction reported thus far. The laser supports spatially confined lasing modes and allows for efficient modulation of spectral profiles by simply tuning the polarization of the pump light. Full-field speckle-free imaging at micron-scales has been achieved by using plasmonic random lasers as the illumination sources. Our findings show that plasmonic metamaterials hold potential to enable intriguing coherent optical sources.

  18. Three-dimensional solidification and melting using magnetic field control

    NASA Technical Reports Server (NTRS)

    Dulikravich, George S.; Ahuja, Vineet

    1993-01-01

    A new two-fluid mathematical model for fully three dimensional steady solidification under the influence of an arbitrary acceleration vector and with or without an arbitrary externally applied steady magnetic field have been formulated and integrated numerically. The model includes Joule heating and allows for separate temperature dependent physical properties within the melt and the solid. Latent heat of phase change during melting/solidification was incorporated using an enthalpy method. Mushy region was automatically captured by varying viscosity orders of magnitude between liquidus and solidus temperature. Computational results were obtained for silicon melt solidification in a parallelepiped container cooled from above and from a side. The results confirm that the magnetic field has a profound influence on the solidifying melt flow field thus changing convective heat transfer through the boundaries and the amount and shape of the solid accrued. This suggests that development of a quick-response algorithm for active control of three dimensional solidification is feasible since it would require low strength magnetic fields.

  19. Three-dimensional confocal optical imagery of precambrian microscopic organisms.

    PubMed

    Schopf, J William; Tripathi, Abhishek B; Kudryavtsev, Anatoliy B

    2006-02-01

    A major difficulty that has long hindered studies of organic-walled Precambrian microbes in petrographic thin sections is the accurate documentation of their three-dimensional morphology. To address this need, we here demonstrate the use of confocal laser scanning microscopy. This technique, both non-intrusive and non-destructive, can provide data by which to objectively characterize, in situ and at submicron-scale resolution, the cellular and organismal morphology of permineralized (petrified) microorganisms. Application of this technique can provide information in three dimensions about the morphology, taphonomy, and fidelity of preservation of such fossils at a spatial resolution unavailable by any other means.

  20. Three-dimensional angular domain optical projection tomography

    NASA Astrophysics Data System (ADS)

    Ng, Eldon; Vasefi, Fartash; Roumeliotis, Michael; Kaminska, Bozena; Carson, Jeffrey J. L.

    2011-03-01

    Angular Domain Imaging (ADI) has been previously demonstrated to generate projection images of attenuating targets embedded within a turbid medium. The imaging system employs a silicon micro-tunnel array positioned between the sample and the detection system to reject scattered photons that have deviated from the initial propagation direction and to select for ballistic and quasi-ballistic photons that have retained their forward trajectory. Two dimensional tomographic images can be reconstructed from ADI projections collected at a multitude of angles. The objective of this work was to extend the system to three dimensions by collecting several tomographic images and stacking the reconstructed slices to generate a three dimensional volume representative of the imaging target. A diode laser (808nm, CW) with a beam expander was used to illuminate the sample cuvette. An Angular Filter Array (AFA) of 80 μm × 80 μm square-shaped tunnels 2 cm in length was used to select for image forming quasi-ballistic photons. Images were detected with a linear CCD. Our approach was to use a SCARA robot to rotate and translate the sample to collect sufficient projections to reconstruct a three dimensional volume. A custom designed 3D target consisting of 4 truncated cones was imaged and reconstructed with filtered backprojection and iterative methods. A 0.5 mm graphite rod was used to collect the forward model, while a truncated pseudoinverse was used to approximate the backward model for the iterative algorithm.

  1. Characterization of a Three-Dimensional Turret Wake for Active Flow Control Part II: Experimental Study

    NASA Astrophysics Data System (ADS)

    Shea, Patrick; Ruscher, Christopher; Wallace, Ryan; Glauser, Mark; Dannenhoffer, John, III

    2010-11-01

    Experimental measurements have been performed to characterize the wake of a three-dimensional, non-conformal turret. Experiments were performed in a low-speed wind tunnel at Syracuse University using particle image velocimetry, hotwire anemometry and dynamic and static pressure measurements. The objective of the study was to characterize the spatial and temporal nature of the wake region as well as to investigate the importance of the incoming flow field. Computational studies have been performed in conjunction with this work to help guide the experimental study and offer insight into the complex three-dimensional flow field. With a better understanding of the wake and three-dimensional characteristics of the turret flow field, closed-loop, active flow control systems will be developed to help reduce fluctuating loading and aero-optical distortions associated with the turbulent flow field.

  2. Three-Dimensional Anisotropic Metamaterials as Triaxial Optical Inclinometers.

    PubMed

    Agarwal, Kriti; Liu, Chao; Joung, Daeha; Park, Hyeong-Ryeol; Oh, Sang-Hyun; Cho, Jeong-Hyun

    2017-06-02

    Split-ring resonators (SRRs) present an attractive avenue for the development of micro/nano scale inclinometers for applications like medical microbots, military hardware, and nanosatellite systems. However, the 180° isotropy of their two-dimensional structure presents a major hurdle. In this paper, we present the design of a three-dimensional (3D) anisotropic SRR functioning as a microscale inclinometer enabling it to remotely sense rotations from 0° to 360° along all three axes (X, Y, and Z), by employing the geometric property of a 3D structure. The completely polymeric composition of the cubic structure renders it transparent to the Terahertz (THz) light, providing a transmission response of the tilted SRRs patterned on its surface that is free of any distortion, coupling, and does not converge to a single point for two different angular positions. Fabrication, simulation, and measurement data have been presented to demonstrate the superior performance of the 3D micro devices.

  3. Integrated three-dimensional optical multilayer using free-space optics.

    PubMed

    Jarczynski, Manfred; Seiler, Thomas; Jahns, Jürgen

    2006-09-01

    An integrated three-dimensional optical multilayer system for optical data communications is presented. It is based on the use of free-space optical light propagation and combines two integration principles, namely, planar and stacked integration. The combination of both integration schemes aims at a maximal design flexibility for complex geometric layouts. On the other hand, packaging issues that stem from assembly and tolerance have to be considered. Here we describe the basic concept and demonstrate the implementation of an optical interface module in a processor-memory bus.

  4. Three-dimensional microscopy by optical scanning holography

    NASA Astrophysics Data System (ADS)

    Poon, Ting-Chung; Doh, Kyu B.; Schilling, Bradley W.; Wu, Ming H.; Shinoda, Kazunori K.; Suzuki, Yoshiji

    1995-05-01

    We first briefly review a new 3D imaging technique called optical scanning holography (OSH). We then discuss the technique's 3D holographic magnification in the context of optical scanning and digital reconstruction. Finally, we demonstrate the 3D imaging capability of OSH by holographically recording two planar objects at different depths and reconstructing the hologram digitally.

  5. Drawing optical fibers from three-dimensional printers.

    PubMed

    Canning, John; Hossain, Md Arafat; Han, Chunyang; Chartier, Loic; Cook, Kevin; Athanaze, Tristan

    2016-12-01

    The temperature distribution within extrusion nozzles of three low-cost desktop 3D printers is characterized using fiber Bragg gratings (FBGs) to assess their compatibility as micro-furnaces for optical fiber and taper production. These profiles show remarkably consistent distributions suitable for direct drawing of optical fiber. As proof of principle, coreless optical fibers (φ=30  μm) made from fluorinated acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate glycol (PETG) are drawn. Cutback measurements demonstrate propagation losses as low as α=0.26  dB/cm, which are comparable with standard optical fiber losses with some room for improvement. This work points toward direct optical fiber manufacture of any material from 3D printers.

  6. Three dimensional reconstruction of conventional stereo optic disc image.

    PubMed

    Kong, H J; Kim, S K; Seo, J M; Park, K H; Chung, H; Park, K S; Kim, H C

    2004-01-01

    Stereo disc photograph was analyzed and reconstructed as 3 dimensional contour image to evaluate the status of the optic nerve head for the early detection of glaucoma and the evaluation of the efficacy of treatment. Stepwise preprocessing was introduced to detect the edge of the optic nerve head and retinal vessels and reduce noises. Paired images were registered by power cepstrum method and zero-mean normalized cross-correlation. After Gaussian blurring, median filter application and disparity pair searching, depth information in the 3 dimensionally reconstructed image was calculated by the simple triangulation formula. Calculated depth maps were smoothed through cubic B-spline interpolation and retinal vessels were visualized more clearly by adding reference image. Resulted 3 dimensional contour image showed optic cups, retinal vessels and the notching of the neural rim of the optic disc clearly and intuitively, helping physicians in understanding and interpreting the stereo disc photograph.

  7. Rewritable three-dimensional holographic data storage via optical forces

    SciTech Connect

    Yetisen, Ali K.; Montelongo, Yunuen; Butt, Haider

    2016-08-08

    The development of nanostructures that can be reversibly arranged and assembled into 3D patterns may enable optical tunability. However, current dynamic recording materials such as photorefractive polymers cannot be used to store information permanently while also retaining configurability. Here, we describe the synthesis and optimization of a silver nanoparticle doped poly(2-hydroxyethyl methacrylate-co-methacrylic acid) recording medium for reversibly recording 3D holograms. We theoretically and experimentally demonstrate organizing nanoparticles into 3D assemblies in the recording medium using optical forces produced by the gradients of standing waves. The nanoparticles in the recording medium are organized by multiple nanosecond laser pulses to produce reconfigurable slanted multilayer structures. We demonstrate the capability of producing rewritable optical elements such as multilayer Bragg diffraction gratings, 1D photonic crystals, and 3D multiplexed optical gratings. We also show that 3D virtual holograms can be reversibly recorded. This recording strategy may have applications in reconfigurable optical elements, data storage devices, and dynamic holographic displays.

  8. Rewritable three-dimensional holographic data storage via optical forces

    NASA Astrophysics Data System (ADS)

    Yetisen, Ali K.; Montelongo, Yunuen; Butt, Haider

    2016-08-01

    The development of nanostructures that can be reversibly arranged and assembled into 3D patterns may enable optical tunability. However, current dynamic recording materials such as photorefractive polymers cannot be used to store information permanently while also retaining configurability. Here, we describe the synthesis and optimization of a silver nanoparticle doped poly(2-hydroxyethyl methacrylate-co-methacrylic acid) recording medium for reversibly recording 3D holograms. We theoretically and experimentally demonstrate organizing nanoparticles into 3D assemblies in the recording medium using optical forces produced by the gradients of standing waves. The nanoparticles in the recording medium are organized by multiple nanosecond laser pulses to produce reconfigurable slanted multilayer structures. We demonstrate the capability of producing rewritable optical elements such as multilayer Bragg diffraction gratings, 1D photonic crystals, and 3D multiplexed optical gratings. We also show that 3D virtual holograms can be reversibly recorded. This recording strategy may have applications in reconfigurable optical elements, data storage devices, and dynamic holographic displays.

  9. Three-dimensional polymer thermo-optic switch at 650 nm

    NASA Astrophysics Data System (ADS)

    Yu, Yueyang; He, Guobing; Ji, Lanting; Wang, Qizhe; Sun, Xiaoqiang; Wang, Xibin; Yi, Yunji; Chen, Changming; Zhang, Daming

    2017-05-01

    Dynamic optical power distribution has great importance to network optimization. A three-dimensional (3-D) polymer thermo-optic switch is designed and fabricated to work at 650 nm. Two rectangular poly(methyl-methacrylate-glycidly-methacrylate) waveguides in neighboring and parallel layers couple with each other in a vertical direction. The lightwave is routed in two layers through a metal heater control. Waveguide configuration and relative position are optimized theoretically through beam propagation method calculations. The fabricated switch demonstrates an extinction ratio of 27.5 dB at a driving power of 57.7 mW. Measured rise time and fall time are 639.8 and 758.2 μs, respectively. Reliability characterizations within 125 days prove good operation stability at different extinction ratios. This work has potential in 3-D optical connections and visible light communication.

  10. Three-dimensional optical manipulation using four collimated intersecting laser beams.

    PubMed

    Huisken, J; Swoger, J; Stelzer, E H

    2007-04-16

    The optical Earnshaw theorem states that a small particle cannot be trapped solely by scattering forces. This limitation is overcome in a novel differential all-optical manipulator. It utilizes four collimated laser beams arranged along the axes of a tetrahedron to confine and move a microscopic sample in an aqueous medium. By adjusting the intensity of each beam individually the magnitude and direction of the optical forces acting on the sample, and via these its position, are controlled. Since only scattering forces are exploited the system is not confined to trapping near a geometrical focus, and therefore enables three-dimensional manipulation over ultra-long working distances. Latex beads 20 microm in diameter can be positioned arbitrarily within a volume defined by the overlap of the four 100 microm diameter beams. The sample is observed from four directions simultaneously, demonstrating the instrument's potential as a universal manipulator in connection with high- and isotropic-resolution light microscopy.

  11. Nonlinear stability and control of three-dimensional boundary layers

    NASA Astrophysics Data System (ADS)

    Janke, Erik

    The linear and nonlinear evolution of steady and traveling disturbances in three-dimensional incompressible boundary layer flows is studied using Parabolized Stability Equations (PSE). Extensive primary stability analyses for the model problems of Swept Hiemenz flow and the DLR Transition experiment on a swept flat plate are performed first. Second, and building upon these results, detailed secondary instability studies based on both the classical Floquet Theory and a novel approach that uses the nonlinear PSE are conducted. The investigations reveal a connection of unstable secondary eigenvalues to both the linear eigenvalue spectrum of the undisturbed mean flow and the continuous spectrum, as well as the existence of an absolute instability in the region of nonlinear amplitude saturation. Third, a passive technique for boundary layer transition control using leading edge roughness is examined utilizing a newly developed implicit solution method for the nonlinear PSE. The results confirm experimental observations and indicate possible means of delaying transition on swept wings. In the present work, both the solution of the boundary layer equations for the mean flow and the explicit PSE solver are based on a fourth-order-accurate compact scheme formulation in body-oriented coordinates. In the secondary instability analysis, the Implicitly Restarted Arnoldi Method is applied.

  12. Three-dimensional focus shaping of partially coherent circularly polarized vortex beams using a binary optic

    NASA Astrophysics Data System (ADS)

    Zhang, Zhou; Fan, Hong; Xu, Hua-Feng; Qu, Jun; Huang, Wei

    2015-06-01

    The three-dimensional (3D) focus shaping technique using the combination of partially coherent circularly polarized vortex beams with a binary diffractive optical element (DOE) is reported. It is found that the intensity distribution near the focus can be tailored in three dimensions by appropriately adjusting the parameters of the incident beams, numerical aperture of the objective lens, and the design of the DOE. Numerical results show that partially coherent circularly polarized vortex beams can be used to generate several special beam patterns, such as optical chain, optical needle, optical dark channel, flat-topped field, and 3D optical cage. Furthermore, compared with the ordinary 3D optical cage, this kind of 3D optical cage generated by our method has a controllable switch; that is, it can be easy to ‘open’ and ‘close’ by controlling the coherence length of the incident beams. Our work may find valuable applications in optical tweezers, microscopes, laser processing, and so on.

  13. Three-dimensional photonic metamaterials at optical frequencies.

    PubMed

    Liu, Na; Guo, Hongcang; Fu, Liwei; Kaiser, Stefan; Schweizer, Heinz; Giessen, Harald

    2008-01-01

    Metamaterials are artificially structured media with unit cells much smaller than the wavelength of light. They have proved to possess novel electromagnetic properties, such as negative magnetic permeability and negative refractive index. This enables applications such as negative refraction, superlensing and invisibility cloaking. Although the physical properties can already be demonstrated in two-dimensional (2D) metamaterials, the practical applications require 3D bulk-like structures. This prerequisite has been achieved in the gigahertz range for microwave applications owing to the ease of fabrication by simply stacking printed circuit boards. In the optical domain, such an elegant method has been the missing building block towards the realization of 3D metamaterials. Here, we present a general method to manufacture 3D optical (infrared) metamaterials using a layer-by-layer technique. Specifically, we introduce a fabrication process involving planarization, lateral alignment and stacking. We demonstrate stacked metamaterials, investigate the interaction between adjacent stacked layers and analyse the optical properties of stacked metamaterials with respect to an increasing number of layers.

  14. Do Three-dimensional Visualization and Three-dimensional Printing Improve Hepatic Segment Anatomy Teaching? A Randomized Controlled Study.

    PubMed

    Kong, Xiangxue; Nie, Lanying; Zhang, Huijian; Wang, Zhanglin; Ye, Qiang; Tang, Lei; Li, Jianyi; Huang, Wenhua

    2016-01-01

    Hepatic segment anatomy is difficult for medical students to learn. Three-dimensional visualization (3DV) is a useful tool in anatomy teaching, but current models do not capture haptic qualities. However, three-dimensional printing (3DP) can produce highly accurate complex physical models. Therefore, in this study we aimed to develop a novel 3DP hepatic segment model and compare the teaching effectiveness of a 3DV model, a 3DP model, and a traditional anatomical atlas. A healthy candidate (female, 50-years old) was recruited and scanned with computed tomography. After three-dimensional (3D) reconstruction, the computed 3D images of the hepatic structures were obtained. The parenchyma model was divided into 8 hepatic segments to produce the 3DV hepatic segment model. The computed 3DP model was designed by removing the surrounding parenchyma and leaving the segmental partitions. Then, 6 experts evaluated the 3DV and 3DP models using a 5-point Likert scale. A randomized controlled trial was conducted to evaluate the educational effectiveness of these models compared with that of the traditional anatomical atlas. The 3DP model successfully displayed the hepatic segment structures with partitions. All experts agreed or strongly agreed that the 3D models provided good realism for anatomical instruction, with no significant differences between the 3DV and 3DP models in each index (p > 0.05). Additionally, the teaching effects show that the 3DV and 3DP models were significantly better than traditional anatomical atlas in the first and second examinations (p < 0.05). Between the first and second examinations, only the traditional method group had significant declines (p < 0.05). A novel 3DP hepatic segment model was successfully developed. Both the 3DV and 3DP models could improve anatomy teaching significantly. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  15. Three-Dimensional Optical Trapping of a Plasmonic Nanoparticle using Low Numerical Aperture Optical Tweezers

    PubMed Central

    Brzobohatý, Oto; Šiler, Martin; Trojek, Jan; Chvátal, Lukáš; Karásek, Vítězslav; Paták, Aleš; Pokorná, Zuzana; Mika, Filip; Zemánek, Pavel

    2015-01-01

    It was previously believed that larger metal nanoparticles behave as tiny mirrors that are pushed by the light beam radiative force along the direction of beam propagation, without a chance to be confined. However, several groups have recently reported successful optical trapping of gold and silver particles as large as 250 nm. We offer a possible explanation based on the fact that metal nanoparticles naturally occur in various non-spherical shapes and their optical properties differ significantly due to changes in localized plasmon excitation. We demonstrate experimentally and support theoretically three-dimensional confinement of large gold nanoparticles in an optical trap based on very low numerical aperture optics. We showed theoretically that the unique properties of gold nanoprisms allow an increase of trapping force by an order of magnitude at certain aspect ratios. These results pave the way to spatial manipulation of plasmonic nanoparticles using an optical fibre, with interesting applications in biology and medicine. PMID:25630432

  16. Finite-element model for three-dimensional optical scattering problems.

    PubMed

    Wei, Xiuhong; Wachters, Arthur J; Urbach, H Paul

    2007-03-01

    We present a three-dimensional model based on the finite-element method for solving the time-harmonic Maxwell equation in optics. It applies to isotropic or anisotropic dielectrics and metals and to many configurations such as an isolated scatterer in a multilayer, bi-gratings, and crystals. We discuss the application of the model to near-field optical recording.

  17. Finite-element model for three-dimensional optical scattering problems

    NASA Astrophysics Data System (ADS)

    Wei, Xiuhong; Wachters, Arthur J.; Urbach, H. Paul

    2007-03-01

    We present a three-dimensional model based on the finite-element method for solving the time-harmonic Maxwell equation in optics. It applies to isotropic or anisotropic dielectrics and metals and to many configurations such as an isolated scatterer in a multilayer, bi-gratings, and crystals. We discuss the application of the model to near-field optical recording.

  18. Structured light optical microscopy for three-dimensional reconstruction of technical surfaces

    NASA Astrophysics Data System (ADS)

    Kettel, Johannes; Reinecke, Holger; Müller, Claas

    2016-04-01

    In microsystems technology quality control of micro structured surfaces with different surface properties is playing an ever more important role. The process of quality control incorporates three-dimensional (3D) reconstruction of specularand diffusive reflecting technical surfaces. Due to the demand on high measurement accuracy and data acquisition rates, structured light optical microscopy has become a valuable solution to solve this problem providing high vertical and lateral resolution. However, 3D reconstruction of specular reflecting technical surfaces still remains a challenge to optical measurement principles. In this paper we present a measurement principle based on structured light optical microscopy which enables 3D reconstruction of specular- and diffusive reflecting technical surfaces. It is realized using two light paths of a stereo microscope equipped with different magnification levels. The right optical path of the stereo microscope is used to project structured light onto the object surface. The left optical path is used to capture the structured illuminated object surface with a camera. Structured light patterns are generated by a Digital Light Processing (DLP) device in combination with a high power Light Emitting Diode (LED). Structured light patterns are realized as a matrix of discrete light spots to illuminate defined areas on the object surface. The introduced measurement principle is based on multiple and parallel processed point measurements. Analysis of the measured Point Spread Function (PSF) by pattern recognition and model fitting algorithms enables the precise calculation of 3D coordinates. Using exemplary technical surfaces we demonstrate the successful application of our measurement principle.

  19. Three-dimensional positioning and control of colloidal objects utilizing engineered liquid crystalline defect networks

    PubMed Central

    Yoshida, H.; Asakura, K.; Fukuda, J.; Ozaki, M.

    2015-01-01

    Topological defects in liquid crystals not only affect the optical and rheological properties of the host, but can also act as scaffolds in which to trap nano or micro-sized colloidal objects. The creation of complex defect shapes, however, often involves confining the liquid crystals in curved geometries or adds complex-shaped colloidal objects, which are unsuitable for device applications. Using topologically patterned substrates, here we demonstrate the controlled generation of three-dimensional defect lines with non-trivial shapes and even chirality, in a flat slab of nematic liquid crystal. By using the defect lines as templates and the electric response of the liquid crystals, colloidal superstructures are constructed, which can be reversibly reconfigured at a voltage as low as 1.3 V. Three-dimensional engineering of the defect shapes in liquid crystals is potentially useful in the fabrication of self-healing composites and in stabilizing artificial frustrated phases. PMID:25994837

  20. Three-dimensional positioning and control of colloidal objects utilizing engineered liquid crystalline defect networks.

    PubMed

    Yoshida, H; Asakura, K; Fukuda, J; Ozaki, M

    2015-05-21

    Topological defects in liquid crystals not only affect the optical and rheological properties of the host, but can also act as scaffolds in which to trap nano or micro-sized colloidal objects. The creation of complex defect shapes, however, often involves confining the liquid crystals in curved geometries or adds complex-shaped colloidal objects, which are unsuitable for device applications. Using topologically patterned substrates, here we demonstrate the controlled generation of three-dimensional defect lines with non-trivial shapes and even chirality, in a flat slab of nematic liquid crystal. By using the defect lines as templates and the electric response of the liquid crystals, colloidal superstructures are constructed, which can be reversibly reconfigured at a voltage as low as 1.3 V. Three-dimensional engineering of the defect shapes in liquid crystals is potentially useful in the fabrication of self-healing composites and in stabilizing artificial frustrated phases.

  1. Experimental investigation of an actively controlled three-dimensional turret wake

    NASA Astrophysics Data System (ADS)

    Shea, Patrick R.

    Hemispherical turrets are bluff bodies commonly used to house optical systems on airborne platforms. These bluff bodies develop complex, three-dimensional flow fields that introduce high mean and fluctuating loads to the turret as well as the airframe support structure which reduce the performance of both the optical systems and the aircraft. An experimental investigation of the wake of a three-dimensional, non-conformal turret was performed in a low-speed wind tunnel at Syracuse University to develop a better understanding of the fundamental flow physics associated with the turret wake. The flow field was studied at a diameter based Reynolds number of 550,000 using stereoscopic particle image velocimetry and dynamic pressure measurements both with and without active flow control. Pressure measurements were simultaneously sampled with the PIV measurements and taken on the surrounding boundary layer plate and at several locations on the turret geometry. Active flow control of the turret wake was performed around the leading edge of the turret aperture using dynamic suction in steady open-loop, unsteady open-loop, and simple closed-loop configurations. Analysis of the uncontrolled wake provided insight into the complex three-dimensional wake when evaluated spatially using PIV measurements and temporally using spectral analysis of the pressure measurements. Steady open-loop suction was found to significantly alter the spatial and temporal nature of the turret wake despite the control being applied locally to the aperture region of the turret. Unsteady open-loop and simple closed-loop control were found to provide similar levels of control to the steady open-loop forcing with a 45% reduction in the control input as calculated using the jet momentum coefficient. The data set collected provides unique information regarding the development of the baseline three-dimensional wake and the wake with three different active flow control configurations. These data can be used to

  2. Optical cell separation from three-dimensional environment in photodegradable hydrogels for pure culture techniques.

    PubMed

    Tamura, Masato; Yanagawa, Fumiki; Sugiura, Shinji; Takagi, Toshiyuki; Sumaru, Kimio; Matsui, Hirofumi; Kanamori, Toshiyuki

    2014-05-07

    Cell sorting is an essential and efficient experimental tool for the isolation and characterization of target cells. A three-dimensional environment is crucial in determining cell behavior and cell fate in biological analysis. Herein, we have applied photodegradable hydrogels to optical cell separation from a 3D environment using a computer-controlled light irradiation system. The hydrogel is composed of photocleavable tetra-arm polyethylene glycol and gelatin, which optimized cytocompatibility to adjust a composition of crosslinker and gelatin. Local light irradiation could degrade the hydrogel corresponding to the micropattern image designed on a laptop; minimum resolution of photodegradation was estimated at 20 µm. Light irradiation separated an encapsulated fluorescent microbead without any contamination of neighbor beads, even at multiple targets. Upon selective separation of target cells in the hydrogels, the separated cells have grown on another dish, resulting in pure culture. Cell encapsulation, light irradiation and degradation products exhibited negligible cytotoxicity in overall process.

  3. Three-dimensional Dirac-like fermions in an optical lattice

    SciTech Connect

    Yang Mou; Zhu Shiliang

    2010-12-15

    We present a scheme to realize three-dimensional Dirac-like fermions with an edge-centered cubic optical lattice. We propose a method to construct the optical edge-centered cubic crystals and then determine the parameters required for the description of the systems with a tight-binding model. Interestingly, we show that the low-energy quasiparticles are three-dimensional massive or massless Dirac-like fermions determined by the parameters of the system. In addition, two three-dimensional degenerate flat bands lie between the upper and the lower branches of the Dirac dispersion. Furthermore, we demonstrate that the Dirac dispersion relation and the flat bands can be verified by the density profile measurement.

  4. Three-dimensional focusing through scattering media using conjugate adaptive optics with remote focusing (CAORF).

    PubMed

    Tao, Xiaodong; Lam, Tuwin; Zhu, Bingzhao; Li, Qinggele; Reinig, Marc R; Kubby, Joel

    2017-05-01

    The small correction volume for conventional wavefront shaping methods limits their application in biological imaging through scattering media. We demonstrate large volume wavefront shaping through a scattering layer with a single correction by conjugate adaptive optics and remote focusing (CAORF). The remote focusing module can maintain the conjugation between the adaptive optical (AO) element and the scattering layer during three-dimensional scanning. This new configuration provides a wider correction volume by better utilization of the memory effect in a fast three-dimensional laser scanning microscope. Our results show that the proposed system can provide 10 times wider axial field of view compared with a conventional conjugate AO system when 16,384 segments are used on a spatial light modulator. We also demonstrate three-dimensional fluorescence imaging, multi-spot patterning through a scattering layer and two-photon imaging through mouse skull tissue.

  5. Estimation of trapping position in three-dimensional off-axis trapping with optical vortices

    NASA Astrophysics Data System (ADS)

    Ando, Taro; Otsu, Tomoko; Takiguchi, Yu; Ohtake, Yoshiyuki; Toyoda, Haruyoshi; Itoh, Hiroyasu

    2014-08-01

    Dynamics of micrometer-sized dielectric objects can be controlled by optical tweezers with scanning light, however, the trapped objects fail to track the scan when drag exceeds the trapping by too quick movement. On the other hand, optical vortices (OVs), which have a property of carrying angular momenta, can directly control torque on objects rather than their position. Laguerre-Gaussian (LG) beams are the most familiar examples of OV and have been studied extensively so far. Revolution of the objects trapped by the LG beams provides typical models of nonequilibrium statistical system, but stable mid-water trapping by the LG beams becomes essential to evaluate physical properties of the system without extrinsic hydrodynamic effects,. Nevertheless, off-axis revolutions of small objects trapped in mid-water by the LG beams have not yet been established with secure evidences. Here we report stable off-axis trapping of dielectric spheres in mid-water using high-quality LG beams generated by a holographic complex-amplitude modulation method. Direct evidence of the three-dimensional off-axis LG trapping was established via estimating the trapping position by measuring the change of revolution radii upon pressing the spheres onto glass walls. Resultantly, the axial trapping position was determined as about half the wavelength behind the beam waist position. This result provides a direct scientific evidence for possibility of off-axis three-dimensional trapping with a single LG beam, moreover, suggests applications as powerful tools for studying energy-conversion mechanisms and nonequilibrium nature in biological molecules under torque.

  6. Optical coherence tomography of cell dynamics in three-dimensional tissue models

    NASA Astrophysics Data System (ADS)

    Tan, Wei; Oldenburg, Amy L.; Norman, James J.; Desai, Tejal A.; Boppart, Stephen A.

    2006-08-01

    Three-dimensional cell-based tissue models have been increasingly useful in the fields of tissue engineering, drug discovery, and cell biology. While techniques for building these tissue models have been advanced, there have been increasing demands for imaging techniques that are capable of assessing complex dynamic three-dimensional cell behavior in real-time and at larger depths in highly-scattering scaffolds. Understanding these cell behaviors requires advanced imaging tools to progress from characterizing two-dimensional cell cultures to complex, highly-scattering, thick three-dimensional tissue constructs. Optical coherence tomography (OCT) is an emerging biomedical imaging technique that can perform cellular-resolution imaging in situ and in real-time. In this study, we demonstrate that it is possible to use OCT to evaluate dynamic cell behavior and function in a quantitative fashion in four dimensions (three-dimensional space plus time). We investigated and characterized in thick tissue models a variety of cell processes, such as chemotaxis migration, proliferation, de-adhesion, and cell-material interactions. This optical imaging technique was developed and utilized in order to gain new insights into how chemical and/or mechanical microenvironments influence cellular dynamics in multiple dimensions. With deep imaging penetration and increased spatial and temporal resolution in three-dimensional space, OCT will be a useful tool for improving our understanding of complex biological interactions at the cellular level.

  7. A three-dimensional optical photonic crystal with designed point defects.

    PubMed

    Qi, Minghao; Lidorikis, Elefterios; Rakich, Peter T; Johnson, Steven G; Joannopoulos, J D; Ippen, Erich P; Smith, Henry I

    2004-06-03

    Photonic crystals offer unprecedented opportunities for miniaturization and integration of optical devices. They also exhibit a variety of new physical phenomena, including suppression or enhancement of spontaneous emission, low-threshold lasing, and quantum information processing. Various techniques for the fabrication of three-dimensional (3D) photonic crystals--such as silicon micromachining, wafer fusion bonding, holographic lithography, self-assembly, angled-etching, micromanipulation, glancing-angle deposition and auto-cloning--have been proposed and demonstrated with different levels of success. However, a critical step towards the fabrication of functional 3D devices, that is, the incorporation of microcavities or waveguides in a controllable way, has not been achieved at optical wavelengths. Here we present the fabrication of 3D photonic crystals that are particularly suited for optical device integration using a lithographic layer-by-layer approach. Point-defect microcavities are introduced during the fabrication process and optical measurements show they have resonant signatures around telecommunications wavelengths (1.3-1.5 microm). Measurements of reflectance and transmittance at near-infrared are in good agreement with numerical simulations.

  8. Design of optical system with three-dimensional image visualization using an array of microlenses

    NASA Astrophysics Data System (ADS)

    Santalina, I. Yu; Toropova, A. P.

    2016-08-01

    The algorithm of calculation of the optical imaging system of a three-dimensional image based on the method of integral photography was given in this article. The algorithm is easy to use and allows the calculate schemes with different microlens arrays, a CCD array of the camera and the projector.

  9. Bessel X waves in two- and three-dimensional bidispersive optical systems.

    PubMed

    Christodoulides, Demetrios N; Efremidis, Nikolaos K; Di Trapani, Paolo; Malomed, Boris A

    2004-07-01

    We show that new families of two- and three-dimensional nondiffracting Bessel X waves are possible in linear bidispersive optical systems. These X waves can be observed in both bulk and waveguide configurations as well as in photonic crystal lattices that simultaneously exhibit normal and anomalous dispersive-diffractive properties in different spatial or spatiotemporal coordinates.

  10. Weyl Points in Three-Dimensional Optical Lattices: Synthetic Magnetic Monopoles in Momentum Space.

    PubMed

    Dubček, Tena; Kennedy, Colin J; Lu, Ling; Ketterle, Wolfgang; Soljačić, Marin; Buljan, Hrvoje

    2015-06-05

    We show that a Hamiltonian with Weyl points can be realized for ultracold atoms using laser-assisted tunneling in three-dimensional optical lattices. Weyl points are synthetic magnetic monopoles that exhibit a robust, three-dimensional linear dispersion, identical to the energy-momentum relation for relativistic Weyl fermions, which are not yet discovered in particle physics. Weyl semimetals are a promising new avenue in condensed matter physics due to their unusual properties such as the topologically protected "Fermi arc" surface states. However, experiments on Weyl points are highly elusive. We show that this elusive goal is well within experimental reach with an extension of techniques recently used in ultracold gases.

  11. Three-dimensional imaging of optically opaque materials using nonionizing terahertz radiation.

    PubMed

    Wallace, Vincent P; Macpherson, Emma; Zeitler, J Axel; Reid, Caroline

    2008-12-01

    Terahertz electromagnetic radiation has already been shown to have a wide number of uses. We consider specific applications of terahertz time-domain imaging that are inherently three-dimensional. This paper highlights the ability of terahertz radiation to reveal subsurface information as we exploit the fact that the radiation can penetrate optically opaque materials such as clothing, cardboard, plastics, and to some extent biological tissue. Using interactive science publishing tools, we concentrate on full three-dimensional terahertz data from three specific areas of application, namely, security, pharmaceutical, and biomedical.

  12. The Lissajous lens: a three-dimensional absolute optical instrument without spherical symmetry.

    PubMed

    Danner, Aaron J; Dao, H L; Tyc, Tomáš

    2015-03-09

    We propose a three dimensional optical instrument with an isotropic gradient index in which all ray trajectories form Lissajous curves. The lens represents the first absolute optical instrument discovered to exist without spherical symmetry (other than trivial cases such as the plane mirror or conformal maps of spherically-symmetric lenses). An important property of this lens is that a three-dimensional region of space can be imaged stigmatically with no aberrations, with a point and its image not necessarily lying on a straight line with the lens center as in all other absolute optical instruments. In addition, rays in the Lissajous lens are not confined to planes. The lens can optionally be designed such that no rays except those along coordinate axes form closed trajectories, and conformal maps of the Lissajous lens form a rich new class of optical instruments.

  13. Three-dimensional deep sub-diffraction optical beam lithography with 9 nm feature size.

    PubMed

    Gan, Zongsong; Cao, Yaoyu; Evans, Richard A; Gu, Min

    2013-01-01

    The current nanofabrication techniques including electron beam lithography provide fabrication resolution in the nanometre range. The major limitation of these techniques is their incapability of arbitrary three-dimensional nanofabrication. This has stimulated the rapid development of far-field three-dimensional optical beam lithography where a laser beam is focused for maskless direct writing. However, the diffraction nature of light is a barrier for achieving nanometre feature and resolution in optical beam lithography. Here we report on three-dimensional optical beam lithography with 9 nm feature size and 52 nm two-line resolution in a newly developed two-photon absorption resin with high mechanical strength. The revealed dependence of the feature size and the two-line resolution confirms that they can reach deep sub-diffraction scale but are limited by the mechanical strength of the new resin. Our result has paved the way towards portable three-dimensional maskless laser direct writing with resolution fully comparable to electron beam lithography.

  14. New advances in three-dimensional controlled-sourceelectromagnetic inversion

    SciTech Connect

    Commer, Michael; Newman, Gregory A.

    2007-05-19

    New techniques for improving both the computational andimaging performance of the three dimensional (3D) electromagnetic inverseproblem are presented. A non-linear conjugate gradient algorithm is theframework of the inversion scheme. Full wave equation modelling forcontrolled sources is utilized for data simulation along with anefficient gradient computation approach for the model update. Improvingthe modelling efficiency of the 3D finite difference method involves theseparation of the potentially large modelling mesh, defining the set ofmodel parameters, from the computational finite difference meshes usedfor field simulation. Grid spacings and thus overall grid sizes can bereduced and optimized according to source frequencies and source-receiveroffsets of a given input data set. Further computational efficiency isobtained by combining different levels of parallelization. While theparallel scheme allows for an arbitrarily large number of parallel tasks,the relative amount of message passing is kept constant. Imageenhancement is achieved by model parameter transformation functions,which enforce bounded conductivity parameters and thus prevent parameterovershoots. Further, a remedy for treating distorted data within theinversion process is presented. Data distortions simulated here includepositioning errors and a highly conductive overburden, hiding the desiredtarget signal. The methods are demonstrated using both synthetic andfield data.

  15. Three-dimensional optical metamaterials as model systems for longitudinal and transverse magnetic coupling.

    PubMed

    Liu, Na; Giessen, Harald

    2008-12-22

    In this paper, we demonstrate that metamaterials represent model systems for longitudinal and transverse magnetic coupling in the optical domain. In particular, such coupling can lead to fully parallel or antiparallel alignment of the magnetic dipoles at the lowest frequency resonance. Also, we present the design scheme for constructing three-dimensional metamaterials with solely magnetic interaction. Our concept could pave the way for achieving rather complicated magnetic materials with desired arrangements of magnetic dipoles at optical frequencies.

  16. Optical chracterization and lasing in three-dimensional opal-structures

    NASA Astrophysics Data System (ADS)

    Nishijima, Yoshiaki; Juodkazis, Saulius

    2015-06-01

    The lasing properties of dye-permeated opal pyramidal structures are compared with the lasing properties of opal films. The opal-structures studied were made by sedimentation of micro-spheres and by sol-gel inversion of the direct-opals. Forced-sedimentation by centrifugation inside wet-etched pyramidal pits on silicon surfaces was used to improve the structural quality of the direct-opal structures. Single crystalline pyramids with the base length of ˜ 100 µm were formed by centrifuged sedimentation. The lasing of dyes in the well-ordered crystalline and poly-crystalline structures showed a distinct multi-modal spectrum. Gain via a distributed feedback was responsible for the lasing since the photonic band gap was negligible in a low refractive index contrast medium; the indices of silica and ethylene glycol are 1.46 and 1.42, respectively. A disordered lasing spectrum was observed from opal films with structural defects and multi-domain regions. The three dimensional structural quality of the structures was assessed by in situ optical diffraction and confocal fluorescence. A correlation between the lasing spectrum and the three-dimensional structural quality was established. Lasing threshold of a sulforhodamine dye in a silica opal was controlled via Förster mechanism by addition of a donor rhodamine 6G dye. The lasing spectrum had a well-ordered modal structure which was spectrally stable at different excitation powers. The sharp lasing threshold characterized by a spontaneous emission coupling ratio β ' 10-2 was obtained.

  17. Three-dimensional deep sub-wavelength defect detection using λ = 193 nm optical microscopy.

    PubMed

    Barnes, Bryan M; Sohn, Martin Y; Goasmat, Francois; Zhou, Hui; Vladár, András E; Silver, Richard M; Arceo, Abraham

    2013-11-04

    Optical microscopy is sensitive both to arrays of nanoscale features and to their imperfections. Optimizing scattered electromagnetic field intensities from deep sub-wavelength nanometer scale structures represents an important element of optical metrology. Current, well-established optical methods used to identify defects in semiconductor patterning are in jeopardy by upcoming sub-20 nm device dimensions. A novel volumetric analysis for processing focus-resolved images of defects is presented using simulated and experimental examples. This new method allows defects as narrow as (16 ± 2) nm (k = 1) to be revealed using 193 nm light with focus and illumination conditions optimized for three-dimensional data analysis. Quantitative metrics to compare two-dimensional and three-dimensional imaging indicate possible fourfold improvements in sensitivity using these methods.

  18. Customized three-dimensional printed optical phantoms with user defined absorption and scattering

    NASA Astrophysics Data System (ADS)

    Pannem, Sanjana; Sweer, Jordan; Diep, Phuong; Lo, Justine; Snyder, Michael; Stueber, Gabriella; Zhao, Yanyu; Tabassum, Syeda; Istfan, Raeef; Wu, Junjie; Erramilli, Shyamsunder; Roblyer, Darren M.

    2016-03-01

    The use of reliable tissue-simulating phantoms spans multiple applications in spectroscopic imaging including device calibration and testing of new imaging procedures. Three-dimensional (3D) printing allows for the possibility of optical phantoms with arbitrary geometries and spatially varying optical properties. We recently demonstrated the ability to 3D print tissue-simulating phantoms with customized absorption (μa) and reduced scattering (μs`) by incorporating nigrosin, an absorbing dye, and titanium dioxide (TiO2), a scattering agent, to acrylonitrile butadiene styrene (ABS) during filament extrusion. A physiologically relevant range of μa and μs` was demonstrated with high repeatability. We expand our prior work here by evaluating the effect of two important 3D-printing parameters, percent infill and layer height, on both μa and μs`. 2 cm3 cubes were printed with percent infill ranging from 10% to 100% and layer height ranging from 0.15 to 0.40 mm. The range in μa and μs` was 27.3% and 19.5% respectively for different percent infills at 471 nm. For varying layer height, the range in μa and μs` was 27.8% and 15.4% respectively at 471 nm. These results indicate that percent infill and layer height substantially alter optical properties and should be carefully controlled during phantom fabrication. Through the use of inexpensive hobby-level printers, the fabrication of optical phantoms may advance the complexity and availability of fully customizable phantoms over multiple spatial scales. This technique exhibits a wider range of adaptability than other common methods of fabricating optical phantoms and may lead to improved instrument characterization and calibration.

  19. Three-dimensional representation of late-arriving photons for detecting inhomogeneities in diffuse optical tomography

    SciTech Connect

    Potlov, A Yu; Proskurin, S G; Frolov, S V

    2014-02-28

    A method for rapid detection of absorbing inhomogeneity in a strongly scattering medium having the properties of a biological tissue before the image reconstruction is described based on the principles of diffuse optical tomography. The method is based on preliminary processing of a three-dimensional surface obtained from the set of time-resolved data in the Cartesian coordinate system, followed by its conformal transformation into two surfaces in the cylindrical coordinate system. A specific feature of the method is the use of late-arriving photons, scattered and diffusely transmitted through an optically turbid object. (optical tomography)

  20. Volumetric display system based on three-dimensional scanning of inclined optical image.

    PubMed

    Miyazaki, Daisuke; Shiba, Kensuke; Sotsuka, Koji; Matsushita, Kenji

    2006-12-25

    A volumetric display system based on three-dimensional (3D) scanning of an inclined image is reported. An optical image of a two-dimensional (2D) display, which is a vector-scan display monitor placed obliquely in an optical imaging system, is moved laterally by a galvanometric mirror scanner. Inclined cross-sectional images of a 3D object are displayed on the 2D display in accordance with the position of the image plane to form a 3D image. Three-dimensional images formed by this display system satisfy all the criteria for stereoscopic vision because they are real images formed in a 3D space. Experimental results of volumetric imaging from computed-tomography images and 3D animated images are presented.

  1. Three-dimensional magnetic trap lattice on an atom chip with an optically induced fictitious magnetic field

    SciTech Connect

    Yan Hui

    2010-05-15

    A robust type of three-dimensional magnetic trap lattice on an atom chip combining optically induced fictitious magnetic field with microcurrent-carrying wires is proposed. Compared to the regular optical lattice, the individual trap in this three-dimensional magnetic trap lattice can be easily addressed and manipulated.

  2. Three-dimensional magnetic trap lattice on an atom chip with an optically induced fictitious magnetic field

    NASA Astrophysics Data System (ADS)

    Yan, Hui

    2010-05-01

    A robust type of three-dimensional magnetic trap lattice on an atom chip combining optically induced fictitious magnetic field with microcurrent-carrying wires is proposed. Compared to the regular optical lattice, the individual trap in this three-dimensional magnetic trap lattice can be easily addressed and manipulated.

  3. On three-dimensional reconstruction of optically thin solar emission sources

    NASA Technical Reports Server (NTRS)

    Kastner, S. O.; Thomas, R. J.; Wade, C.

    1977-01-01

    Calculations are given for constructing the three dimensional distribution of optically thin EUV emission sources associated with solar active regions, from two dimensional observations (projections) recorded by the spectroheliograph on the OSO 7 satellite. The relation of the method to other image reconstruction methods is briefly discussed as well as the special requirements imposed in the solar case such as a knowledge of the true solar rotation function. A useful correlation criterion for establishing the physical validity of solutions is given.

  4. Three-dimensional polarization aberration functions in optical system based on three-dimensional polarization ray-tracing calculus

    NASA Astrophysics Data System (ADS)

    He, Wenjun; Fu, Yuegang; Liu, Zhiying; Zhang, Lei; Wang, Jiake; Zheng, Yang; Li, Yahong

    2017-03-01

    The polarization aberrations of a complex optical system with multi-element lens have been investigated using a 3D polarization aberration function. The 3D polarization ray-tracing matrix has been combined with the optical path difference to obtain a 3D polarization aberration function, which avoids the need for a complicated phase unwrapping process. The polarization aberrations of a microscope objective have been analyzed to include, the distributions of 3D polarization aberration functions, diattenuation aberration, retardance aberration, and polarization-dependent intensity on the exit pupil. Further, the aberrations created by the field of view and the coating on the distribution rules of 3D polarization aberration functions are discussed in detail. Finally a novel appropriate field of view and wavelength correction is proposed for a polarization aberration function which optimizes the image quality of a multi-element optical system.

  5. Three-dimensional control of the helical axis of a chiral nematic liquid crystal by light

    NASA Astrophysics Data System (ADS)

    Zheng, Zhi-Gang; Li, Yannian; Bisoyi, Hari Krishna; Wang, Ling; Bunning, Timothy J.; Li, Quan

    2016-03-01

    Chiral nematic liquid crystals—otherwise referred to as cholesteric liquid crystals (CLCs)—are self-organized helical superstructures that find practical application in, for example, thermography, reflective displays, tuneable colour filters and mirrorless lasing. Dynamic, remote and three-dimensional control over the helical axis of CLCs is desirable, but challenging. For example, the orientation of the helical axis relative to the substrate can be changed from perpendicular to parallel by applying an alternating-current electric field, by changing the anchoring conditions of the substrate, or by altering the topography of the substrate’s surface; separately, in-plane rotation of the helical axis parallel to the substrate can be driven by a direct-current field. Here we report three-dimensional manipulation of the helical axis of a CLC, together with inversion of its handedness, achieved solely with a light stimulus. We use this technique to carry out light-activated, wide-area, reversible two-dimensional beam steering—previously accomplished using complex integrated systems and optical phased arrays. During the three-dimensional manipulation by light, the helical axis undergoes, in sequence, a reversible transition from perpendicular to parallel, followed by in-plane rotation on the substrate surface. Such reversible manipulation depends on experimental parameters such as cell thickness, surface anchoring condition, and pitch length. Because there is no thermal relaxation, the system can be driven either forwards or backwards from any light-activated intermediate state. We also describe reversible photocontrol between a two-dimensional diffraction state, a one-dimensional diffraction state and a diffraction ‘off’ state in a bilayer cell.

  6. Decoupling control of three-dimensional drive in robot

    NASA Astrophysics Data System (ADS)

    Huang, Shenghua; Fu, Guangjie

    1995-12-01

    Spherical motor, in principle, can make 3D rotation, with the advantages of small volume, less transmission chains and flexibly-controlled so as to be used for the drive in robot joints. This paper establishes a mechanics model of 3D drive of spherical motor with Lagrangian energy method. The result displays that there are serious nonlinear coupling torques among the shafts when the motor make 3D rotation. It further studies the method that rebuilds equivalent coupling torques with the help of spatial state detector, and decoupling control tactics to realize robot's 3D drive by means of feed forward, etc. It also gives a tactics of decoupling control in order to real-time implement this theory, and computer-aided numerical results of the entirely decoupling control, simplified decoupling control and undecoupling control are presented and compared. The results of simulation and sample machine's experiments are given to present this mathematics model and the decoupling control tactics are available and feasible.

  7. Dual focused coherent beams for three-dimensional optical trapping and continuous rotation of metallic nanostructures

    PubMed Central

    Xu, Xiaohao; Cheng, Chang; Zhang, Yao; Lei, Hongxiang; Li, Baojun

    2016-01-01

    Metallic nanoparticles and nanowires are extremely important for nanoscience and nanotechnology. Techniques to optically trap and rotate metallic nanostructures can enable their potential applications. However, because of the destabilizing effects of optical radiation pressure, the optical trapping of large metallic particles in three dimensions is challenging. Additionally, the photothermal issues associated with optical rotation of metallic nanowires have far prevented their practical applications. Here, we utilize dual focused coherent beams to realize three-dimensional (3D) optical trapping of large silver particles. Continuous rotation of silver nanowires with frequencies measured in several hertz is also demonstrated based on interference-induced optical vortices with very low local light intensity. The experiments are interpreted by numerical simulations and calculations. PMID:27386838

  8. Dual focused coherent beams for three-dimensional optical trapping and continuous rotation of metallic nanostructures

    NASA Astrophysics Data System (ADS)

    Xu, Xiaohao; Cheng, Chang; Zhang, Yao; Lei, Hongxiang; Li, Baojun

    2016-07-01

    Metallic nanoparticles and nanowires are extremely important for nanoscience and nanotechnology. Techniques to optically trap and rotate metallic nanostructures can enable their potential applications. However, because of the destabilizing effects of optical radiation pressure, the optical trapping of large metallic particles in three dimensions is challenging. Additionally, the photothermal issues associated with optical rotation of metallic nanowires have far prevented their practical applications. Here, we utilize dual focused coherent beams to realize three-dimensional (3D) optical trapping of large silver particles. Continuous rotation of silver nanowires with frequencies measured in several hertz is also demonstrated based on interference-induced optical vortices with very low local light intensity. The experiments are interpreted by numerical simulations and calculations.

  9. Structurally Efficient Three-dimensional Metamaterials with Controllable Thermal Expansion.

    PubMed

    Xu, Hang; Pasini, Damiano

    2016-10-10

    The coefficient of thermal expansion (CTE) of architected materials, as opposed to that of conventional solids, can be tuned to zero by intentionally altering the geometry of their structural layout. Existing material architectures, however, achieve CTE tunability only with a sacrifice in structural efficiency, i.e. a drop in both their stiffness to mass ratio and strength to mass ratio. In this work, we elucidate how to resolve the trade-off between CTE tunability and structural efficiency and present a lightweight bi-material architecture that not only is stiffer and stronger than other 3D architected materials, but also has a highly tunable CTE. Via a combination of physical experiments on 3D fabricated prototypes and numeric simulations, we demonstrate how two distinct mechanisms of thermal expansion appearing in a tetrahedron, can be exploited in an Octet lattice to generate a large range of CTE values, including negative, zero, or positive, with no loss in structural efficiency. The novelty and simplicity of the proposed design as well as the ease in fabrication, make this bi-material architecture well-suited for a wide range of applications, including satellite antennas, space optical systems, precision instruments, thermal actuators, and MEMS.

  10. Structurally Efficient Three-dimensional Metamaterials with Controllable Thermal Expansion

    PubMed Central

    Xu, Hang; Pasini, Damiano

    2016-01-01

    The coefficient of thermal expansion (CTE) of architected materials, as opposed to that of conventional solids, can be tuned to zero by intentionally altering the geometry of their structural layout. Existing material architectures, however, achieve CTE tunability only with a sacrifice in structural efficiency, i.e. a drop in both their stiffness to mass ratio and strength to mass ratio. In this work, we elucidate how to resolve the trade-off between CTE tunability and structural efficiency and present a lightweight bi-material architecture that not only is stiffer and stronger than other 3D architected materials, but also has a highly tunable CTE. Via a combination of physical experiments on 3D fabricated prototypes and numeric simulations, we demonstrate how two distinct mechanisms of thermal expansion appearing in a tetrahedron, can be exploited in an Octet lattice to generate a large range of CTE values, including negative, zero, or positive, with no loss in structural efficiency. The novelty and simplicity of the proposed design as well as the ease in fabrication, make this bi-material architecture well-suited for a wide range of applications, including satellite antennas, space optical systems, precision instruments, thermal actuators, and MEMS. PMID:27721437

  11. Structurally Efficient Three-dimensional Metamaterials with Controllable Thermal Expansion

    NASA Astrophysics Data System (ADS)

    Xu, Hang; Pasini, Damiano

    2016-10-01

    The coefficient of thermal expansion (CTE) of architected materials, as opposed to that of conventional solids, can be tuned to zero by intentionally altering the geometry of their structural layout. Existing material architectures, however, achieve CTE tunability only with a sacrifice in structural efficiency, i.e. a drop in both their stiffness to mass ratio and strength to mass ratio. In this work, we elucidate how to resolve the trade-off between CTE tunability and structural efficiency and present a lightweight bi-material architecture that not only is stiffer and stronger than other 3D architected materials, but also has a highly tunable CTE. Via a combination of physical experiments on 3D fabricated prototypes and numeric simulations, we demonstrate how two distinct mechanisms of thermal expansion appearing in a tetrahedron, can be exploited in an Octet lattice to generate a large range of CTE values, including negative, zero, or positive, with no loss in structural efficiency. The novelty and simplicity of the proposed design as well as the ease in fabrication, make this bi-material architecture well-suited for a wide range of applications, including satellite antennas, space optical systems, precision instruments, thermal actuators, and MEMS.

  12. Three Dimensional Pursuit Guidance and Control of Submersible Vehicles

    DTIC Science & Technology

    1991-09-01

    kinematic relations in the control design and, as a result, the controller tends to be more sensitive to actual system / mathematical model mismatch. The...and simulations and stability results are presented. A. EQUATIONS OF MOTION For the horizontal plane the mathematical model consists of the nonlinear...force Y and yaw moment N are presented below: (v+ r) 3 ]d +Nsu26 N=N.t+ (N,.Y%+N.ur)-+Nuv--.p-f[Ch(t) ’v+ &r)tI N62 5 To complete the model

  13. Three dimensional visualization to support command and control

    SciTech Connect

    Van Slambrook, G.A.

    1997-04-01

    Virtual reality concepts are changing the way one thinks about and with computers. The concepts have already proven their potential usefulness in a broad range of applications. This research was concerned with exploring and demonstrating the utility of virtual reality in robotics and satellite command and control applications. The robotics work addressed the need to quickly build accurate graphical models of physical environments by allowing a user to interactively build a model of a remote environment by superimposing stereo graphics onto live stereo video. The satellite work addressed the fusion of multiple data sets or models into one synergistic display for more effective training, design, and command and control of satellite systems.

  14. Microfluidic device for the formation of optically excitable, three-dimensional, compartmentalized motor units

    PubMed Central

    Uzel, Sebastien G. M.; Platt, Randall J.; Subramanian, Vidya; Pearl, Taylor M.; Rowlands, Christopher J.; Chan, Vincent; Boyer, Laurie A.; So, Peter T. C.; Kamm, Roger D.

    2016-01-01

    Motor units are the fundamental elements responsible for muscle movement. They are formed by lower motor neurons and their muscle targets, synapsed via neuromuscular junctions (NMJs). The loss of NMJs in neurodegenerative disorders (such as amyotrophic lateral sclerosis or spinal muscle atrophy) or as a result of traumatic injuries affects millions of lives each year. Developing in vitro assays that closely recapitulate the physiology of neuromuscular tissues is crucial to understand the formation and maturation of NMJs, as well as to help unravel the mechanisms leading to their degeneration and repair. We present a microfluidic platform designed to coculture myoblast-derived muscle strips and motor neurons differentiated from mouse embryonic stem cells (ESCs) within a three-dimensional (3D) hydrogel. The device geometry mimics the spinal cord–limb physical separation by compartmentalizing the two cell types, which also facilitates the observation of 3D neurite outgrowth and remote muscle innervation. Moreover, the use of compliant pillars as anchors for muscle strips provides a quantitative functional readout of force generation. Finally, photosensitizing the ESC provides a pool of source cells that can be differentiated into optically excitable motor neurons, allowing for spatiodynamic, versatile, and noninvasive in vitro control of the motor units. PMID:27493991

  15. Three-dimensional modular control of human walking.

    PubMed

    Allen, Jessica L; Neptune, Richard R

    2012-08-09

    Recent studies have suggested that complex muscle activity during walking may be controlled using a reduced neural control strategy organized around the co-excitation of multiple muscles, or modules. Previous computer simulation studies have shown that five modules satisfy the sagittal-plane biomechanical sub-tasks of 2D walking. The present study shows that a sixth module, which contributes primarily to mediolateral balance control and contralateral leg swing, is needed to satisfy the additional non-sagittal plane demands of 3D walking. Body support was provided by Module 1 (hip and knee extensors, hip abductors) in early stance and Module 2 (plantarflexors) in late stance. In early stance, forward propulsion was provided by Module 4 (hamstrings), but net braking occurred due to Modules 1 and 2. Forward propulsion was provided by Module 2 in late stance. Module 1 accelerated the body medially throughout stance, dominating the lateral acceleration in early stance provided by Modules 4 and 6 (adductor magnus) and in late stance by Module 2, except near toe-off. Modules 3 (ankle dorsiflexors, rectus femoris) and 5 (hip flexors and adductors except adductor magnus) accelerated the ipsilateral leg forward in early swing whereas Module 4 decelerated the ipsilateral leg prior to heel-strike. Finally, Modules 1, 4 and 6 accelerated the contralateral leg forward prior to and during contralateral swing. Since the modules were based on experimentally measured muscle activity, these results provide further evidence that a simple neural control strategy involving muscle activation modules organized around task-specific biomechanical functions may be used to control complex human movements. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Three-Dimensional Modular Control of Human Walking

    PubMed Central

    Allen, Jessica L.; Neptune, Richard R.

    2012-01-01

    Recent studies have suggested that complex muscle activity during walking may be controlled using a reduced neural control strategy organized around the co-excitation of multiple muscles, or modules. Previous computer simulation studies have shown that five modules satisfy the sagittal-plane biomechanical sub-tasks of 2D walking. The present study shows that a sixth module, which contributes primarily to mediolateral balance control and contralateral leg swing, is needed to satisfy the additional non-sagittal plane demands of 3D walking. Body support was provided by Module 1 (hip and knee extensors, hip abductors) in early stance and Module 2 (plantarflexors) in late stance. In early stance, forward propulsion was provided by Module 4 (hamstrings), but net braking occurred due to Modules 1 and 2. Forward propulsion was provided by Module 2 in late stance. Module 1 accelerated the body medially throughout stance, dominating the lateral acceleration in early stance provided by Modules 4 and 6 (adductor magnus) and in late stance by Module 2, except near toe-off. Modules 3 (ankle dorsiflexors, rectus femoris) and 5 (hip flexors and adductors except adductor magnus) accelerated the ipsilateral leg forward in early swing whereas Module 4 decelerated the ipsilateral leg prior to heel-strike. Finally, Modules 1, 4 and 6 accelerated the contralateral leg forward prior to and during contralateral swing. Since the modules were based on experimentally measured muscle activity, these results provide further evidence that a simple neural control strategy involving muscle activation modules organized around task-specific biomechanical functions may be used to control complex human movements. PMID:22727468

  17. High-beamforming power-code-multiplexed optical scanner for three-dimensional displays

    NASA Astrophysics Data System (ADS)

    Arain, Muzammil A.; Riza, Nabeel A.

    2003-11-01

    Three dimensional (3-D) displays play an important role in the field of entertainment. Today, research is being conducted to produce 3-D displays to meet the complex needs of high-functionality full motion 3D displays at reasonable cost, but without glasses, complicated viewing arrangements or restricted fields of view. Other applications for 3-D displays include but are not limited to CAD/Design simulation, advanced data representation, displaying complex 3-D information for automotive design, medical imaging, advanced navigation displays, scientific visualization, and advertising. The key element in all these applications is an optical beam scanner that can display 3-D images for large viewing angles. Our proposed Code Multiplexed Optical Scanner (C-MOS) can fulfill all these requirements with its high beamforming power capabilities. Our proposed experiment demonstrates three dimensional (3-D) beam scanning with large angles (e.g., > 160°), large centimeter size aperture, and scanning speed of <300 μsec. The robust construction and simple operation of the C-MOS makes it very useful and attractive for deployment in the field of entertainment, defense and medical imaging. Here we report the application of the C-MOS for three dimensional (3-D) displays.

  18. Review on recent progress of three-dimensional optical photonic crystal

    SciTech Connect

    Hsieh, Mei-Li; Kuang, Ping; Bur, James A.; Lin, Shawn-Yu; John, Sajeev

    2014-03-31

    Over the past two decades, the field of photonic-crystals has become one of the most influential realms of contemporary optics. In this paper, we will review two recent experimental progresses in three-dimensional photonic-crystal operating in optical wavelengths. The first is the observation of anomalous light-refraction, an acutely negative refraction, in a 3D photonic-crystal for light trapping, guiding and near-unity absorption. The second is the observation of quasi-coherent thermal emission from an all-metallic 3D photonic-crystal at elevated temperatures.

  19. Optical mapping near-eye three-dimensional display with correct focus cues

    NASA Astrophysics Data System (ADS)

    Cui, Wei; Gao, Liang

    2017-07-01

    We present an optical mapping near-eye (OMNI) three-dimensional display method for wearable devices. By dividing a display screen into different sub-panels and optically mapping them to various depths, we create a multiplane volumetric image with correct focus cues for depth perception. The resultant system can drive the eye's accommodation to the distance that is consistent with binocular stereopsis, thereby alleviating the vergence-accommodation conflict, the primary cause for eye fatigue and discomfort. Compared with the previous methods, the OMNI display offers prominent advantages in adaptability, image dynamic range, and refresh rate.

  20. DNA origami-directed, discrete three-dimensional plasmonic tetrahedron nanoarchitectures with tailored optical chirality.

    PubMed

    Dai, Gaole; Lu, Xuxing; Chen, Zhong; Meng, Chun; Ni, Weihai; Wang, Qiangbin

    2014-04-23

    Discrete, three-dimensional (3D) gold nanoparticle (AuNP) tetrahedron nanoarchitectures are successfully self-assembled with DNA origami as template with high purity (>85%). A distinct plasmonic chiral response is experimentally observed from the AuNP tetrahedron nanoarchitectures and appears in a configuration-dependent manner. The chiral optical properties are then rationally engineered by modifying the structural parameters including the AuNP size and interparticle distance. Theoretical study of the AuNP tetrahedron nanoarchitectures shows the dependence of the chiral optical property on the AuNP size and interparticle distance, consistent with the ensemble averaged measurements.

  1. Encrypted optical memory system using three-dimensional keys in the Fresnel domain.

    PubMed

    Matoba, O; Javidi, B

    1999-06-01

    An encrypted optical memory system using double random phase codes in the Fresnel domain is proposed. In this system, two random phase codes and their positions form three-dimensional keys for encryption of images and are used as keys to recover the original data. The third dimension is the positions of the codes, which can have as many as three degrees of freedom. Original images encrypted by use of the two phase codes located in the Fresnel domain are stored holographically in a photorefractive material. We demonstrate in preliminary experiments encryption and decryption of optical memory in a LiNbO(3) :Fe photorefractive crystal by use of angular multiplexing.

  2. Three dimensional image reconstruction based on a wide-field optical coherence tomography system

    NASA Astrophysics Data System (ADS)

    Feng, Yinqi; Feng, Shengtong; Zhang, Min; Hao, Junjun

    2014-07-01

    Wide-field optical coherence tomography has a promising application for its high scanning rate and resolution. The principle of a wide-field optical coherence tomography system is described, and 2D images of glass slides are reconstructed using eight-stepped phase-shifting method in the system. Using VC6.0 and OpenGL programming, 3D images are reconstructed based on the Marching Cube algorithm with 2D image sequences. The experimental results show that the depth detection and three-dimensional tomography for translucent materials could be implemented efficiently in the WFOCT system.

  3. Three-dimensional speckle reduction in optical coherence tomography through structural guided filtering

    NASA Astrophysics Data System (ADS)

    Gyger, Cyrill; Cattin, Roger; Hasler, Pascal W.; Maloca, Peter

    2014-07-01

    Optical coherence tomography (OCT) is a high-resolution noninvasive technology used in medical imaging for the spatial visualization of biological tissue. Due to its coherent nature, OCT suffers from speckle noise, which significantly degrades the information content of resulting scans. We introduce a new filtering method for three-dimensional OCT images, inspired by film grain removal techniques. By matching structural relatedness along all dimensions, the algorithm builds up vector paths for every voxel in the image volume representing its structural neighborhood. Then, by considering the information redundancy along these paths, our filter is able to reduce speckle noise significantly while simultaneously preserving structural information. This filter exceeds some common three-dimensional denoising algorithms used for OCT images, both in visual rendering quality and in measurable noise reduction. The noise-reduced results allow for improvement in subsequent processing steps, such as image segmentation.

  4. A three-dimensional wide-angle BPM for optical waveguide structures.

    PubMed

    Ma, Changbao; Van Keuren, Edward

    2007-01-22

    Algorithms for effective modeling of optical propagation in three- dimensional waveguide structures are critical for the design of photonic devices. We present a three-dimensional (3-D) wide-angle beam propagation method (WA-BPM) using Hoekstra's scheme. A sparse matrix algebraic equation is formed and solved using iterative methods. The applicability, accuracy and effectiveness of our method are demonstrated by applying it to simulations of wide-angle beam propagation, along with a technique for shifting the simulation window to reduce the dimension of the numerical equation and a threshold technique to further ensure its convergence. These techniques can ensure the implementation of iterative methods for waveguide structures by relaxing the convergence problem, which will further enable us to develop higher-order 3-D WA-BPMs based on Padé approximant operators.

  5. Multi-particle three-dimensional coordinate estimation in real-time optical manipulation

    NASA Astrophysics Data System (ADS)

    Dam, J. S.; Perch-Nielsen, I.; Palima, D.; Gluckstad, J.

    2009-11-01

    We have previously shown how stereoscopic images can be obtained in our three-dimensional optical micromanipulation system [J. S. Dam et al, Opt. Express 16, 7244 (2008)]. Here, we present an extension and application of this principle to automatically gather the three-dimensional coordinates for all trapped particles with high tracking range and high reliability without requiring user calibration. Through deconvolving of the red, green, and blue colour planes to correct for bleeding between colour planes, we show that we can extend the system to also utilize green illumination, in addition to the blue and red. Applying the green colour as on-axis illumination yields redundant information for enhanced error correction, which is used to verify the gathered data, resulting in reliable coordinates as well as producing visually attractive images.

  6. Spatially controlled cell adhesion on three-dimensional substrates.

    PubMed

    Richter, Christine; Reinhardt, Martina; Giselbrecht, Stefan; Leisen, Daniel; Trouillet, Vanessa; Truckenmüller, Roman; Blau, Axel; Ziegler, Christiane; Welle, Alexander

    2010-10-01

    The microenvironment of cells in vivo is defined by spatiotemporal patterns of chemical and biophysical cues. Therefore, one important goal of tissue engineering is the generation of scaffolds with defined biofunctionalization in order to control processes like cell adhesion and differentiation. Mimicking extrinsic factors like integrin ligands presented by the extracellular matrix is one of the key elements to study cellular adhesion on biocompatible scaffolds. By using special thermoformable polymer films with anchored biomolecules micro structured scaffolds, e.g. curved and micro-patterned substrates, can be fabricated. Here, we present a novel strategy for the fabrication of micro-patterned scaffolds based on the "Substrate Modification and Replication by Thermoforming" (SMART) technology: The surface of a poly lactic acid membrane, having a low forming temperature of 60 degrees C and being initially very cell attractive, was coated with a photopatterned layer of poly(L-lysine) (PLL) and hyaluronic acid (VAHyal) to gain spatial control over cell adhesion. Subsequently, this modified polymer membrane was thermoformed to create an array of spherical microcavities with diameters of 300 microm for 3D cell culture. Human hepatoma cells (HepG2) and mouse fibroblasts (L929) were used to demonstrate guided cell adhesion. HepG2 cells adhered and aggregated exclusively within these cavities without attaching to the passivated surfaces between the cavities. Also L929 cells adhering very strongly on the pristine substrate polymer were effectively patterned by the cell repellent properties of the hyaluronic acid based hydrogel. This is the first time cell adhesion was controlled by patterned functionalization of a polymeric substrate with UV curable PLL-VAHyal in thermoformed 3D microstructures.

  7. Spatially controlled cell adhesion on three-dimensional substrates

    PubMed Central

    Richter, Christine; Reinhardt, Martina; Giselbrecht, Stefan; Leisen, Daniel; Trouillet, Vanessa; Truckenmüller, Roman; Blau, Axel; Ziegler, Christiane

    2010-01-01

    The microenvironment of cells in vivo is defined by spatiotemporal patterns of chemical and biophysical cues. Therefore, one important goal of tissue engineering is the generation of scaffolds with defined biofunctionalization in order to control processes like cell adhesion and differentiation. Mimicking extrinsic factors like integrin ligands presented by the extracellular matrix is one of the key elements to study cellular adhesion on biocompatible scaffolds. By using special thermoformable polymer films with anchored biomolecules micro structured scaffolds, e.g. curved and µ-patterned substrates, can be fabricated. Here, we present a novel strategy for the fabrication of µ-patterned scaffolds based on the “Substrate Modification and Replication by Thermoforming” (SMART) technology: The surface of a poly lactic acid membrane, having a low forming temperature of 60°C and being initially very cell attractive, was coated with a photopatterned layer of poly(L-lysine) (PLL) and hyaluronic acid (VAHyal) to gain spatial control over cell adhesion. Subsequently, this modified polymer membrane was thermoformed to create an array of spherical microcavities with diameters of 300 µm for 3D cell culture. Human hepatoma cells (HepG2) and mouse fibroblasts (L929) were used to demonstrate guided cell adhesion. HepG2 cells adhered and aggregated exclusively within these cavities without attaching to the passivated surfaces between the cavities. Also L929 cells adhering very strongly on the pristine substrate polymer were effectively patterned by the cell repellent properties of the hyaluronic acid based hydrogel. This is the first time cell adhesion was controlled by patterned functionalization of a polymeric substrate with UV curable PLL-VAHyal in thermoformed 3D microstructures. PMID:20480241

  8. Controlling tokamak geometry with three-dimensional magnetic perturbations

    SciTech Connect

    Bird, T. M.; Hegna, C. C.

    2014-10-15

    It is shown that small externally applied magnetic perturbations can significantly alter important geometric properties of magnetic flux surfaces in tokamaks. Through 3D shaping, experimentally relevant perturbation levels are large enough to influence turbulent transport and MHD stability in the pedestal region. It is shown that the dominant pitch-resonant flux surface deformations are primarily induced by non-resonant 3D fields, particularly in the presence of significant axisymmetric shaping. The spectral content of the applied 3D field can be used to control these effects.

  9. Investigation of three-dimensional mesh generation with precise controls

    NASA Astrophysics Data System (ADS)

    Eiseman, Peter R.

    1989-01-01

    In the grant, a number of accomplishments were made in a variety of ways and in a variety of topics. The ways in which this was achieved were in oral communication with others, in the organization of conferences, in the journal publications, in the direction of graduate studies, and in the computer demonstration of theoretical developments. The topics include a study of shock-vortex interaction and a number of studies in grid generation. Those studies covered algebraic and interactive aspects here converged with the establishment of a powerful control point formulation for arbitrary grid generation.

  10. Optical cryptography topology based on a three-dimensional particle-like distribution and diffractive imaging.

    PubMed

    Chen, Wen; Chen, Xudong

    2011-05-09

    In recent years, coherent diffractive imaging has been considered as a promising alternative for information retrieval instead of conventional interference methods. Coherent diffractive imaging using the X-ray light source has opened up a new research perspective for the measurement of non-crystalline and biological specimens, and can achieve unprecedentedly high resolutions. In this paper, we show how a three-dimensional (3D) particle-like distribution and coherent diffractive imaging can be applied for a study of optical cryptography. An optical multiple-random-phase-mask encoding approach is used, and the plaintext is considered as a series of particles distributed in a 3D space. A topology concept is also introduced into the proposed optical cryptosystem. During image decryption, a retrieval algorithm is developed to extract the plaintext from the ciphertexts. In addition, security and advantages of the proposed optical cryptography topology are also analyzed. © 2011 Optical Society of America

  11. Multimodal three-dimensional imaging with isotropic high resolution using optical projection tomography

    NASA Astrophysics Data System (ADS)

    Miao, Qin; Rahn, J. Richard; Bryant, Ryland C.; Lancaster, Christy A.; Tourovskaia, Anna; Neumann, Thomas; Seibel, Eric J.; Nelson, Alan C.

    2009-02-01

    The optical projection tomography microscope (OPTM) is an optical microscope that acquires focus-invariant images from multiple views of single cells. Although the depth of field of the objective is short, it can be extended by scanning the objective's focal plane. This extended depth of field image is similar to a projection in conventional X-ray CT. Samples flow through a microcapillary tube filled with optical gel. Optical distortion is minimized by matching refractive index of optical gel and tube. Multiple projection images are taken by rotating the microcapillary tube with sub-micron mechanical precision. After these pseudoprojection images are further aligned, computed tomography methods are then applied to the images to create a 3D reconstruction with isometric resolution of 0.35 microns. Three-dimensional reconstructed images of fluorescent microspheres and cells are shown.

  12. 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.

  13. Design of virtual three-dimensional instruments for sound control

    NASA Astrophysics Data System (ADS)

    Mulder, Axel Gezienus Elith

    An environment for designing virtual instruments with 3D geometry has been prototyped and applied to real-time sound control and design. It enables a sound artist, musical performer or composer to design an instrument according to preferred or required gestural and musical constraints instead of constraints based only on physical laws as they apply to an instrument with a particular geometry. Sounds can be created, edited or performed in real-time by changing parameters like position, orientation and shape of a virtual 3D input device. The virtual instrument can only be perceived through a visualization and acoustic representation, or sonification, of the control surface. No haptic representation is available. This environment was implemented using CyberGloves, Polhemus sensors, an SGI Onyx and by extending a real- time, visual programming language called Max/FTS, which was originally designed for sound synthesis. The extension involves software objects that interface the sensors and software objects that compute human movement and virtual object features. Two pilot studies have been performed, involving virtual input devices with the behaviours of a rubber balloon and a rubber sheet for the control of sound spatialization and timbre parameters. Both manipulation and sonification methods affect the naturalness of the interaction. Informal evaluation showed that a sonification inspired by the physical world appears natural and effective. More research is required for a natural sonification of virtual input device features such as shape, taking into account possible co- articulation of these features. While both hands can be used for manipulation, left-hand-only interaction with a virtual instrument may be a useful replacement for and extension of the standard keyboard modulation wheel. More research is needed to identify and apply manipulation pragmatics and movement features, and to investigate how they are co-articulated, in the mapping of virtual object

  14. Three-dimensional in vivo scanning microscopy with inertia-free focus control

    NASA Astrophysics Data System (ADS)

    Dal Maschio, Marco; Michela de Stasi, Angela; Benfenati, Fabio; Fellin, Tommaso

    2011-09-01

    The acquisition of high-resolution images in three dimensions is of utmost importance for the morphological and functional investigation of biological tissues. Here, we present a laser scanning two-photon microscope with remote and motionless control of the focus position. The movement of the excitation spot along the propagation direction is achieved by shaping the laser wavefront with a spatial light modulator. Depending on the optical properties of the objective in use, this approach allows z movements in a range of tens to hundreds of micrometers with small changes of the point spread function. We applied this technique for the three-dimensional (3D) imaging of fluorescent cells in the mouse neocortex in vivo. The presented system bypasses the limitations of microscopes based on moving objectives, enabling high-resolution inertia-free 3D imaging.

  15. Three-Dimensional Composite Nanostructures for Lean NOx Emission Control

    SciTech Connect

    Gao, Pu-Xian

    2013-07-31

    This final report to the Department of Energy (DOE) and National Energy Technology Laboratory (NETL) for DE-EE0000210 covers the period from October 1, 2009 to July 31, 2013. Under this project, DOE awarded UConn about $1,248,242 to conduct the research and development on a new class of 3D composite nanostructure based catalysts for lean NOx emission control. Much of the material presented here has already been submitted to DOE/NETL in quarterly technical reports. In this project, through a scalable solution process, we have successfully fabricated a new class of catalytic reactors, i.e., the composite nanostructure array (nano-array) based catalytic converters. These nanocatalysts, distinct from traditional powder washcoat based catalytic converters, directly integrate monolithic substrates together with nanostructures with well-defined size and shape during the scalable hydrothermal process. The new monolithic nanocatalysts are demonstrated to be able to save raw materials including Pt-group metals and support metal oxides by an order of magnitude, while perform well at various oxidation (e.g., CO oxidation and NO oxidation) and reduction reactions (H{sub 2} reduction of NOx) involved in the lean NOx emissions. The size, shape and arrangement of the composite nanostructures within the monolithic substrates are found to be the key in enabling the drastically reduced materials usage while maintaining the good catalytic reactivity in the enabled devices. The further understanding of the reaction kinetics associated with the unique mass transport and surface chemistry behind is needed for further optimizing the design and fabrication of good nanostructure array based catalytic converters. On the other hand, the high temperature stability, hydrothermal aging stability, as well as S-poisoning resistance have been investigated in this project on the nanocatalysts, which revealed promising results toward good chemical and mechanical robustness, as well as S

  16. Experimental Study of the Temporal Nature of an Actively Controlled Three Dimensional Turret Wake

    NASA Astrophysics Data System (ADS)

    Shea, Patrick; Glauser, Mark

    2011-11-01

    Experimental measurements have been performed to characterize the actively controlled wake of a three-dimensional, non- conformal turret which is a bluff body commonly used for housing optical systems on airborne platforms. As a bluff body, turrets can generate strong turbulent flow fields that degrade the performance of the optical systems and the aircraft. Experiments were performed in a low-speed wind tunnel at Syracuse University using particle image velocimetry and dynamic pressure measurements with the objective of developing a better understanding of the spatial and temporal nature of the wake flow field. Active control was achieved using dynamic suction in the vicinity of the turret aperture and was found to have a significant impact on the structure of the wake as well as the temporal characteristics of the flow field. With a better understanding of the wake characteristics, closed-loop, active flow control systems will be developed to help reduce fluctuating loading and aero- optical distortions associated with the turbulent flow field.

  17. In vivo images of the epidural space with two- and three-dimensional optical coherence tomography in a porcine model

    PubMed Central

    Tsou, Mei-Yung

    2017-01-01

    Background No reports exist concerning in vivo optical coherence tomography visualization of the epidural space and the blood patch process in the epidural space. In this study, we produced real-time two-dimensional and reconstructed three-dimensional images of the epidural space by using optical coherence tomography in a porcine model. We also aimed to produce three-dimensional optical coherence tomography images of the dura puncture and blood patch process. Methods Two-dimensional and three-dimensional optical coherence tomography images were obtained using a swept source optical coherence tomography (SSOCT) system. Four laboratory pigs were intubated and ventilated after the induction of general anesthesia. An 18-gauge Tuohy needle was used as a tunnel for the optical coherence tomography probe to the epidural space. Two-dimensional and three-dimensional reconstruction optical coherence tomography images of the epidural space were acquired in four stages. Results In stage 1, real-time two-dimensional and reconstructed three-dimensional optical coherence tomography of the lumbar and thoracic epidural space were successfully acquired. In stage 2, the epidural catheter in the epidural space was successfully traced in the 3D optical coherence tomography images. In stage 3, water injection and lumbar puncture were successfully monitored in all study animals. In stage 4, 10 mL of fresh blood was injected into the epidural space and two-dimensional and three-dimensional optical coherence tomography images were successfully acquired. Conclusions These animal experiments suggest the potential capability of using an optical coherence tomography-based imaging needle in the directed two-dimensional and three-dimensional visualization of the epidural space. More investigations involving humans are required before optical coherence tomography can be recommended for routine use. However, three-dimensional optical coherence tomography may provide a novel, minimally invasive

  18. In vivo images of the epidural space with two- and three-dimensional optical coherence tomography in a porcine model.

    PubMed

    Kuo, Wen-Chuan; Kao, Meng-Chun; Tsou, Mei-Yung; Ting, Chien-Kun

    2017-01-01

    No reports exist concerning in vivo optical coherence tomography visualization of the epidural space and the blood patch process in the epidural space. In this study, we produced real-time two-dimensional and reconstructed three-dimensional images of the epidural space by using optical coherence tomography in a porcine model. We also aimed to produce three-dimensional optical coherence tomography images of the dura puncture and blood patch process. Two-dimensional and three-dimensional optical coherence tomography images were obtained using a swept source optical coherence tomography (SSOCT) system. Four laboratory pigs were intubated and ventilated after the induction of general anesthesia. An 18-gauge Tuohy needle was used as a tunnel for the optical coherence tomography probe to the epidural space. Two-dimensional and three-dimensional reconstruction optical coherence tomography images of the epidural space were acquired in four stages. In stage 1, real-time two-dimensional and reconstructed three-dimensional optical coherence tomography of the lumbar and thoracic epidural space were successfully acquired. In stage 2, the epidural catheter in the epidural space was successfully traced in the 3D optical coherence tomography images. In stage 3, water injection and lumbar puncture were successfully monitored in all study animals. In stage 4, 10 mL of fresh blood was injected into the epidural space and two-dimensional and three-dimensional optical coherence tomography images were successfully acquired. These animal experiments suggest the potential capability of using an optical coherence tomography-based imaging needle in the directed two-dimensional and three-dimensional visualization of the epidural space. More investigations involving humans are required before optical coherence tomography can be recommended for routine use. However, three-dimensional optical coherence tomography may provide a novel, minimally invasive, and safe way to observe the spinal

  19. Optical computed tomography in PRESAGE(®) three-dimensional dosimetry: Challenges and prospective.

    PubMed

    Khezerloo, Davood; Nedaie, Hassan Ali; Farhood, Bagher; Zirak, Alireza; Takavar, Abbas; Banaee, Nooshin; Ahmadalidokht, Isa; Kron, Tomas

    2017-01-01

    With the advent of new complex but precise radiotherapy techniques, the demands for an accurate, feasible three-dimensional (3D) dosimetry system have been increased. A 3D dosimeter system generally should not only have accurate and precise results but should also feasible, inexpensive, and time consuming. Recently, one of the new candidates for 3D dosimetry is optical computed tomography (CT) with a radiochromic dosimeter such as PRESAGE®. Several generations of optical CT have been developed since the 90s. At the same time, a large attempt has been also done to introduce the robust dosimeters that compatible with optical CT scanners. In 2004, PRESAGE® dosimeter as a new radiochromic solid plastic dosimeters was introduced. In this decade, a large number of efforts have been carried out to enhance optical scanning methods. This article attempts to review and reflect on the results of these investigations.

  20. Three-dimensional analysis of optical forces generated by an active tractor beam using radial polarization.

    PubMed

    Carretero, Luis; Acebal, Pablo; Blaya, Salvador

    2014-02-10

    We theoretically study the three-dimensional behavior of nanoparticles in an active optical conveyor. To do this, we solved the Langevin equation when the forces are generated by a focusing system at the near field. Analytical expressions for the optical forces generated by the optical conveyor were obtained by solving the Richards and Wolf vectorial diffraction integrals in an approximated form when a mask of two annular pupils is illuminated by a radially polarized Hermite-Gauss beam. Trajectories, in both the transverse plane and the longitudinal direction, are analyzed showing that the behavior of the optical conveyor can be optimized by conveniently choosing the configuration of the mask of the two annular pupils (inner and outer radius of the two rings) in order to trap and transport all particles at the focal plane.

  1. Interference-based optical image encryption using three-dimensional phase retrieval.

    PubMed

    Chen, Wen; Chen, Xudong

    2012-09-01

    In recent years, optical image encryption has attracted more and more attention in information security due to its unique advantages, such as parallel processing and multiple-parameter characteristics. In this paper, we propose a new method using three-dimensional (3D) processing strategy for interference-based optical image encryption. The plaintext is considered as a series of particles distributed in 3D space, and any one sectional extraction cannot render information about the plaintext during image decryption. In addition, the silhouette problem in the conventional interference-based optical encryption method is effectively suppressed, and the proposed optical cryptosystem can achieve higher security compared with the previous work. A numerical experiment is conducted to demonstrate the feasibility and effectiveness of the proposed method.

  2. Noncontact three-dimensional quantitative profiling of fast aspheric lenses by optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Goud, Bujagouni Karthik; Udupa, Dinesh Venkatesh; Prathap, Chilakala; Shinde, Deepak Dilip; Rao, Kompalli Divakar; Sahoo, Naba Kishore

    2016-12-01

    The use of optical coherence tomography (OCT) for noncontact three-dimensional aspheric lens profiling and retrieval of aspheric surface parameters is demonstrated. Two commercially available aspheric lenses with different focal length-to-diameter ratio have been imaged using OCT, and the measured optical path length distribution has been least square fitted with the aspheric lens surface retrieving the radius of curvature, aspheric constant, and conic constants. The refractive index of these lenses has also been measured referencing with a standard Zerodur glass flat. The fitted aspheric surface coefficients of the lenses are in close agreement with the manufacturer's values, thus, envisaging the potential of OCT in rapid screening, testing of aspheric lenses, and other micro-optical components such as those used in illumination optics.

  3. Three-dimensional nanometry of vesicle transport in living cells using dual-focus imaging optics

    SciTech Connect

    Watanabe, Tomonobu M.; Sato, Takashi; Gonda, Kohsuke; Higuchi, Hideo . E-mail: higuchi@tubero.tohoku.ac.jp

    2007-07-20

    Dual-focus imaging optics for three-dimensional tracking of individual quantum dots has been developed to study the molecular mechanisms of motor proteins in cells. The new system has a high spatial and temporal precision, 2 nm in the x-y sample plane and 5 nm along the z-axis at a frame time of 2 ms. Three-dimensional positions of the vesicles labeled with quantum dots were detected in living cells. Vesicles were transported on the microtubules using 8-nm steps towards the nucleus. The steps had fluctuation of {approx}20 nm which were perpendicular to the axis of the microtubule but with the constant distance from the microtubule. The most of perpendicular movement was not synchronized with the 8-nm steps, indicating that dynein moved on microtubules without changing the protofilaments. When the vesicles changed their direction of movement toward the cell membrane, they moved perpendicular with the constant distance from the microtubule. The present method is powerful tool to investigate three dimensional movement of molecules in cells with nanometer and millisecond accuracy.

  4. Unconventional optical Tamm states in metal-terminated three-dimensional photonic crystals

    NASA Astrophysics Data System (ADS)

    Korovin, Alexander V.; Romanov, Sergei G.

    2016-03-01

    Unconventional optical Tamm surface states have been demonstrated in transmission and reflectance spectra of three-dimensional opal photonic crystals coated by thin metal films. These states appear in registry with diffraction resonances and localize the electromagnetic energy in asymmetric resonators formed by stacks of lattice planes and metal semishells. Tamm defect states provide the bypass for light at the edges of the Bragg diffraction resonances and thus reduce the diffraction efficiency. Despite the hidden nature of this effect, its magnitude is comparable to the extraordinary transmission associated with the surface-plasmon polaritons that are simultaneously excited at the surfaces of the corrugated metal films.

  5. Optical magnetic response in three-dimensional metamaterial of upright plasmonic meta-molecules.

    PubMed

    Chen, Wei Ting; Chen, Chen Jung; Wu, Pin Chieh; Sun, Shulin; Zhou, Lei; Guo, Guang-Yu; Hsiao, Chinh Ting; Yang, Kuang-Yu; Zheludev, Nikolay I; Tsai, Din Ping

    2011-06-20

    We report the first three-dimensional photonic metamaterial, an array of erected U-shape plasmonic gold meta-molecules, that exhibits a profound response to the magnetic field of light incident normal to the array. The metamaterial was fabricated using a double exposure e-beam lithographic process. It was investigated by optical measurements and finite-element simulations, and showed that the magnetic field solely depends on the plasmonic resonance mode showing either enhanced in the centre of the erected U-shape meta-molecule (16 times enhancement) or enhanced around two prongs of erected U-shape meta-molecule (4 times enhancement).

  6. Three-dimensional optical metrology with color-coded extended depth of focus.

    PubMed

    Hasman, E; Keren, S; Davidson, N; Friesem, A A

    1999-04-01

    A novel method of rapid three-dimensional optical metrology that is based on triangulation of a configuration of color-coded light stripes is presented. The method exploits polychromatic illumination and a combined diffractive-refractive element, so the incident light is focused upon a stripe that is axially dispersed, greatly increasing the depth-measuring range without any decrease in the axial or the lateral resolution. The discrimination of each color stripe is further improved by spectral coding and decoding techniques. An 18-fold increase in the depth of focus was experimentally obtained while diffraction-limited light stripes were completely maintained.

  7. Three-dimensional localization of fluorescent targets in turbid media using time reversal optical tomography

    NASA Astrophysics Data System (ADS)

    Wu, Binlin; Cai, W.; Gayen, S. K.

    2012-12-01

    An optical tomography approach for locating fluorescent targets embedded inside a turbid medium is introduced. It uses multi-source probing and multi-detector signal acquisition to collect diffuse fluorescence signal, and time reversal matrix formalism with subspace based signal processing for image reconstruction. It could provide three-dimensional position co-ordinates of two small fluorescent targets embedded in Intralipid-20% suspension of thickness ˜60 times the transport mean free path with an accuracy of ˜1 mm. Fast reconstruction and high spatial resolution make the approach potentially suited for detecting and locating contrast-enhanced breast tumor at early stages of growth.

  8. Temporal response of three-dimensional biological cells to high-frequency optical jumping tweezers

    NASA Astrophysics Data System (ADS)

    Yu, Lingyao; Sheng, Yunlong

    2015-01-01

    We analyzed the temporal responses of biological cells in the jumping optical tweezers for tugging, wiggling, and stretching the cells in the time-sharing regime with the finite-element method. We showed that the jumping of local stress and local strain is independently omnipresent on the recovery time of the viscoelastic material and the jumping frequency of the load. We demonstrated that the elongation of a three-dimensional (3-D) viscoelastic object under a jumping load cannot be evaluated using the one-dimensional spring-dashpot material model without considering its 3-D structure.

  9. In-Situ Three-Dimensional Shape Rendering from Strain Values Obtained Through Optical Fiber Sensors

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    A method and system for rendering the shape of a multi-core optical fiber or multi-fiber bundle in three-dimensional space in real time based on measured fiber strain data. Three optical fiber cores arc arranged in parallel at 120.degree. intervals about a central axis. A series of longitudinally co-located strain sensor triplets, typically fiber Bragg gratings, are positioned along the length of each fiber at known intervals. A tunable laser interrogates the sensors to detect strain on the fiber cores. Software determines the strain magnitude (.DELTA.L/L) for each fiber at a given triplet, but then applies beam theory to calculate curvature, beading angle and torsion of the fiber bundle, and from there it determines the shape of the fiber in s Cartesian coordinate system by solving a series of ordinary differential equations expanded from the Frenet-Serrat equations. This approach eliminates the need for computationally time-intensive curve-tilting and allows the three-dimensional shape of the optical fiber assembly to be displayed in real-time.

  10. Photo-written three-dimensional optical circuits in iron doped lithium niobate crystals

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Zhao, Jianlin; Xu, Honglai; Ma, Yanghua; Yang, Dexing

    2006-02-01

    We present our experimental results on fabricating optical waveguides by laser micromachining, structure-light illuminating, and optical spatial dark solitons in iron doped lithium niobate (LiNbO 3:Fe) crystals. After that we propose a novel approach to fabricate three-dimensional (3-D) optical circuits in LiNbO 3 crystals by combining the three light-induction techniques listed above. By employing laser micromachining, a curved and a Y-branches waveguides are successfully fabricated. With binary and SLM-prepared optical masks, Y-branches and gradient planar waveguides are experimentally demonstrated. By utilizing one-dimensional (1-D) optical spatial dark solitons, planar, Y-branches, and square channel waveguides are formed. The results show that each of the three methods can be employed to write optical waveguides in LiNbO3 crystals. By combing the three methods, 3-D light circuits can be created in 45 °-cut bulk crystals by several procedures. Initially, a quasi-planar optical circuit is created in a thin layer of the crystal by structure-light illuminating with an optical mask. Then, a planar circuit is generated by utilizing a 1-D dark soltion. And then, form multi-layer planar circuits are formed by altering the positions of the crystal or writing beam. Finally, laser micromachining is used to link the different layers to form a 3-D light circuit. Furthermore, functional 3-D integrated optical system may be implemented by using the proposed approach.

  11. Three dimensional controlled assembly of gold nanoparticles using a micromachined platform

    NASA Astrophysics Data System (ADS)

    Khanduja, Nishant; Selvarasah, Selvapraba; Chen, Chia-Ling; Dokmeci, Mehmet R.; Xiong, Xugang; Makaram, Prashanth; Busnaina, Ahmed

    2007-02-01

    By using optical lithographic procedures, the authors present a micromachined platform for large scale three dimensional (3D) assembly of gold nanoparticles with diameters of ˜50nm. The gold nanoparticles are formed into 3D low resistance bridges (two terminal resistance of ˜40Ω) interconnecting the two microelectrodes using ac dielectrophoresis. The thickness of the parylene interlevel dielectric can be adjusted to vary the height of the 3D platform for meeting different application requirements. This research represents a step towards realizing high density, three dimensional structures and devices for applications such as nanosensors, vertical integration of nanosystems, and characterization of nanomaterials.

  12. Photonic nanojets as three-dimensional optical atom traps: A theoretical study

    NASA Astrophysics Data System (ADS)

    Yannopapas, Vassilios

    2012-06-01

    We show that an efficient three-dimensional optical atom trap can be achieved by light scattered off a dielectric microsphere. Namely, under suitable conditions, a plane wave incident on a polymer sphere produces a focal point in the forward scattering direction known as photonic nanojet. The photonic nanojet is formed at a distance of a few micrometers away from the surface of the sphere wherein the Casimir-Polder interaction felt by an atom is negligible compared to the optical and gravitational potentials. When many polymer spheres are brought together so as to form a linear chain, a one-dimensional periodic optical lattice filled with cold atoms is possible since interference between the incident and scattered beams is minimal when the spheres are not too close.

  13. Optical spectroscopy study of the three-dimensional Dirac semimetal ZrTe5

    DOE PAGES

    Chen, R. Y.; Gu, G. D.; Zhang, S. J.; ...

    2015-08-05

    Three-dimensional (3D) topological Dirac materials have been under intensive study recently. The layered compound ZrTe5 has been suggested to be one such material as a result of transport and angle-resolved photoemission spectroscopy experiments. Here, we perform infrared reflectivity measurements to investigate the underlying physics of this material. The derived optical conductivity increases linearly with frequency below normal interband transitions, which provides optical spectroscopic proof of a 3D Dirac semimetal. In addition, the plasma edge shifts dramatically to lower energy upon temperature cooling, which might be due to the shrinking of the lattice parameters. Additionally, an extremely sharp peak shows upmore » in the frequency-dependent optical conductivity, indicating the presence of a Van Hove singularity in the joint density of state.« less

  14. Physical origin of the high energy optical response of three dimensional photonic crystals.

    PubMed

    Dorado, Luis A; Depine, Ricardo A; Lozano, Gabriel; Míguez, Hernán

    2007-12-24

    The physical origin of the optical response observed in three-dimensional photonic crystals when the photon wavelength is equal or lower than the lattice parameter still remains unsatisfactorily explained and is the subject of an intense and interesting debate. Herein we demonstrate for the first time that all optical spectra features in this high energy region of photonic crystals arise from electromagnetic resonances within the ordered array, modified by the interplay between these resonances with the opening of diffraction channels, the presence of imperfections and finite size effects. All these four phenomena are taken into account in our theoretical approach to the problem, which allows us to provide a full description of the observed optical response based on fundamental phenomena as well as to attain fair fittings of experimental results.

  15. Optical properties of woodpile photonic crystals produced by three-dimensional laser lithography

    NASA Astrophysics Data System (ADS)

    Samusev, K. B.; Rybin, M. V.; Samusev, A. K.; Limonov, M. F.

    2015-12-01

    Photonic crystals having a woodpile lattice structure with the lateral sizes of up to 200 × 200 μm and lattice period of 1 to 2 μm have been produced by additive three-dimensional laser lithography. The sample structure has been analyzed by optical and scanning electron microscopy. The ideal woodpile consists of "logs" with a rectangular cross section but, in the synthesized structures, the angles are rounded. Calculations of the photonic band structure of woodpiles, in which the cross sections of logs are specified by the Lame curves, have made it possible to estimate the influence of the rounding on the optical properties. Due to significant sample sizes, patterns of optical diffraction in white and monochromatic light have been studied experimentally. The experimental results have been interpreted using calculations of diffraction patterns in the Born approximation of scattering theory.

  16. Optical spectroscopy study of the three-dimensional Dirac semimetal ZrTe5

    SciTech Connect

    Chen, R. Y.; Gu, G. D.; Zhang, S. J.; Schneeloch, J. A.; Zhang, C.; Li, Q.; Wang, N. L.

    2015-08-05

    Three-dimensional (3D) topological Dirac materials have been under intensive study recently. The layered compound ZrTe5 has been suggested to be one such material as a result of transport and angle-resolved photoemission spectroscopy experiments. Here, we perform infrared reflectivity measurements to investigate the underlying physics of this material. The derived optical conductivity increases linearly with frequency below normal interband transitions, which provides optical spectroscopic proof of a 3D Dirac semimetal. In addition, the plasma edge shifts dramatically to lower energy upon temperature cooling, which might be due to the shrinking of the lattice parameters. Additionally, an extremely sharp peak shows up in the frequency-dependent optical conductivity, indicating the presence of a Van Hove singularity in the joint density of state.

  17. Dynamic control of polarization-inverted modes in three-dimensionally trapped multiple nanogaps

    SciTech Connect

    Tamura, Mamoru; Iida, Takuya

    2015-12-28

    We propose a guiding principle for the dynamic control of polarization-inverted modes in multiple nanogaps for unconventional optical transitions of molecules at arbitrary three-dimensional spatial positions. Based on our developed self-consistent theory for the optical assembly of nanoparticles (NPs), we clarified that spherical silver NPs can be optically trapped and aligned in the light-propagating direction via longitudinally polarized light; they form a rod-like nano-composite with multiple nanogaps. During trapping, there is a possibility that an additional irradiation of linearly polarized far-field light may excite the bonding and anti-bonding dark plasmon modes with low radiative decay rate of several meV via cancellation of inverted polarization. Our finding reveals that not only the steep change in the enhanced intensity of light field but also the phase inversion of light field between the dynamically formed nanogaps will pave the way to the highly sensitive sensors for molecules, the unconventional chemical reactions, and so on.

  18. Smart agile lens remote optical sensor for three-dimensional object shape measurements.

    PubMed

    Riza, Nabeel A; Reza, Syed Azer

    2010-03-01

    We demonstrate what is, to the best of our knowledge, the first electronically controlled variable focus lens (ECVFL)-based sensor for remote object shape sensing. Using a target illuminating laser, the axial depths of the shape features on a given object are measured by observing the intensity profile of the optical beam falling on the object surface and tuning the ECVFL focal length to form a minimum beam spot. Using a lens focal length control calibration table, the object feature depths are computed. Transverse measurement of the dimensions of each object feature is done using a surface-flooding technique that completely illuminates a given feature. Alternately, transverse measurements can also be made by the variable spatial sampling scan technique, where, depending upon the feature sizes, the spatial sampling spot beam size is controlled using the ECVFL. A proof-of-concept sensor is demonstrated using an optical beam from a laser source operating at a power of 10 mW and a wavelength of 633 nm. A three-dimensional (3D) test object constructed from LEGO building blocks forms has three mini-skyscraper structures labeled A, B, and C. The (x, y, z) dimensions for A, B, and C are (8 mm, 8 mm, 124.84 mm), (24.2 mm, 24.2 mm, 38.5 mm), and (15.86 mm, 15.86 mm, 86.74 mm), respectively. The smart sensor experimentally measured (x,y,z) dimensions for A, B, C are (7.95 mm, 7.95 mm, 120 mm), (24.1 mm, 24.1 mm, 37 mm), and (15.8 mm, 15.8 mm, 85 mm), respectively. The average shape sensor transverse measurement percentage errors for A, B, and C are +/-0.625%, +/-0.41%, and +/-0.38%, respectively. The average shape sensor axial measurement percentage errors for A, B, and C are +/-4.03%, +/-3.9%, and +/-2.01%, respectively. Applications for the proposed shape sensor include machine parts inspection, 3D object reconstruction, and animation.

  19. Determination of Sound Velocity in Three-Dimensional Space by Optical Probe

    NASA Astrophysics Data System (ADS)

    Ohbuchi, Takeshi; Mizutani, Koichi; Wakatsuki, Naoto; Masuyama, Hiroyuki

    2008-05-01

    We propose a method of determining a three-dimensional sound velocity using a Michelson interferometer, optical computerized tomography (O-CT) and near-field acoustical holography (NAH). Ultrasonic waves affect the phase of the test light passing through radiated sound fields. The zeroth-order diffraction light including sound pressure information is electrically acquired by an avalanche photodiode (APD). Projection data along the optical axis is obtained by single linear scanning in the range of ±30 mm and electronically quadrature-detected as a complex amplitude. Eighteen projections are acquired in the range of 0≤θ<π rad, and the complex sound fields are reconstructed in a region of 40×40 mm2 by O-CT. Then another plane separated by 1 mm is propagated using NAH from the acquired sound fields, and the same plane is reconstructed. Comparing the phase of the reconstructed and propagated sound fields in wave number domain, we determine the three-dimensional sound velocity in a region of 40×40×1 mm3. The experimental results are in agreement with the reference value.

  20. [Microanatomic and three-dimensional reconstruction study of lateral wall and related structures of optic canal].

    PubMed

    Yang, Jun; Wu, Xi; Liu, Ji-Xiang; Lin, Rui-Sheng; Li, Zhi-Qiang; Ma, Shun-Chang; Qi, Jian-Fa; Cun, En-Hao; Yu, Chun-Jiang

    2011-02-01

    To investigate the key microanatomic and radiological structures of optic canal comprehensively so as to provide anatomic parameters and procedural flows for the decompression of optic canal. Gross observations and microscopic measurements were applied on 10 (20 sides) formalin-treated cadaveric specimens and 15 (30 sides) adult skulls. Using multislice helical CT (computed tomography)-aided three-dimensional reconstruction in combination with direct anatomic measurement, the investigators dissected, photographed, measured and analyzed the shape of optic canal and analyze its anatomic relationship with the adjoining structures. Optic canal was formed by the superior, inferior, medial and external walls and distal proximal opening. The lateral wall of optic canal was formed by anterior clinoid process with a length of (9.87 ± 1.34) mm, a width of (11.66 ± 2.35) mm, a base thickness of (5.35 ± 1.07) mm and a middle thickness of (4.50 ± 1.06) mm. Optic strut separating the optic canal from the superior orbital fissure was located inferiorly. And the distance between the apex of anterior clinoid process and the middle of ICA (internal carotid artery) groove was (4.25 ± 2.30) mm. The CSF (cerebrospinal fluid) leakage and secondary injury of optic nerve and injury of ICA, ophthalmic artery might occur during the surgical procedures due to the variation of anterior clinoid process. The microanatomic figures and radiological measurements had a mean difference very close to each other at (0.08 - 0.48) mm. No statistical difference was found (P > 0.05). Optic nerve, ophthalmic artery and ICA may be exposed by a high-speed drilling of the lateral wall of optic canal. The drilling dissection of lateral wall plays a vital role during a successful optic canal decompression. Radiological measurement and three-dimensional reconstruction of skull base may be of great clinical significance in lesion visualization. And it helps to make a better choice of surgical approaches. The

  1. Enhanced control of light and sound trajectories with three-dimensional gradient index lenses

    NASA Astrophysics Data System (ADS)

    Chang, T. M.; Dupont, G.; Enoch, S.; Guenneau, S.

    2012-03-01

    We numerically study the focusing and bending effects of light and sound waves through heterogeneous isotropic cylindrical and spherical devices. We first point out that transformation optics and acoustics show that the control of light requires spatially varying anisotropic permittivity and permeability, while the control of sound is achieved via spatially anisotropic density and isotropic compressibility. Moreover, homogenization theory applied to electromagnetic and acoustic periodic structures leads to such artificial (although not spatially varying) anisotropic permittivity, permeability and density. We stress that homogenization is thus a natural mathematical tool for the design of structured metamaterials. To illustrate the two-step geometric transform-homogenization approach, we consider the design of cylindrical and spherical electromagnetic and acoustic lenses displaying some artificial anisotropy along their optical axis (direction of periodicity of the structural elements). Applications are sought in the design of Eaton and Luneburg lenses bending light at angles ranging from 90° to 360°, or mimicking a Schwartzchild metric, i.e. a black hole. All of these spherical metamaterials are characterized by a refractive index varying inversely with the radius which is approximated by concentric layers of homogeneous material. We finally propose some structured cylindrical metamaterials consisting of infinitely conducting or rigid toroidal channels in a homogeneous bulk material focusing light or sound waves. The functionality of these metamaterials is demonstrated via full-wave three-dimensional computations using nodal elements in the context of acoustics, and finite edge-elements in electromagnetics.

  2. Three-dimensional printed optical phantoms with customized absorption and scattering properties.

    PubMed

    Diep, Phuong; Pannem, Sanjana; Sweer, Jordan; Lo, Justine; Snyder, Michael; Stueber, Gabriella; Zhao, Yanyu; Tabassum, Syeda; Istfan, Raeef; Wu, Junjie; Erramilli, Shyamsunder; Roblyer, Darren

    2015-11-01

    Three-dimensional (3D) printing offers the promise of fabricating optical phantoms with arbitrary geometry, but commercially available thermoplastics provide only a small range of physiologically relevant absorption (µa) and reduced scattering (µs`) values. Here we demonstrate customizable acrylonitrile butadiene styrene (ABS) filaments for dual extrusion 3D printing of tissue mimicking optical phantoms. µa and µs` values were adjusted by incorporating nigrosin and titanium dioxide (TiO2) in the filament extrusion process. A wide range of physiologically relevant optical properties was demonstrated with an average repeatability within 11.5% for µa and 7.71% for µs`. Additionally, a mouse-simulating phantom, which mimicked both the geometry and optical properties of a hairless mouse with an implanted xenograft tumor, was printed using dual extrusion methods. 3D printed tumor optical properties matched the live tumor with less than 3% error at a wavelength of 659 nm. 3D printing with user defined optical properties may provide a viable method for durable optically diffusive phantoms for instrument characterization and calibration.

  3. Three-dimensional printed optical phantoms with customized absorption and scattering properties

    PubMed Central

    Diep, Phuong; Pannem, Sanjana; Sweer, Jordan; Lo, Justine; Snyder, Michael; Stueber, Gabriella; Zhao, Yanyu; Tabassum, Syeda; Istfan, Raeef; Wu, Junjie; Erramilli, Shyamsunder; Roblyer, Darren

    2015-01-01

    Three-dimensional (3D) printing offers the promise of fabricating optical phantoms with arbitrary geometry, but commercially available thermoplastics provide only a small range of physiologically relevant absorption (µa) and reduced scattering (µs`) values. Here we demonstrate customizable acrylonitrile butadiene styrene (ABS) filaments for dual extrusion 3D printing of tissue mimicking optical phantoms. µa and µs` values were adjusted by incorporating nigrosin and titanium dioxide (TiO2) in the filament extrusion process. A wide range of physiologically relevant optical properties was demonstrated with an average repeatability within 11.5% for µa and 7.71% for µs`. Additionally, a mouse-simulating phantom, which mimicked both the geometry and optical properties of a hairless mouse with an implanted xenograft tumor, was printed using dual extrusion methods. 3D printed tumor optical properties matched the live tumor with less than 3% error at a wavelength of 659 nm. 3D printing with user defined optical properties may provide a viable method for durable optically diffusive phantoms for instrument characterization and calibration. PMID:26600987

  4. Three-dimensional optoelectronic stacked processor by use of free-space optical interconnection and three-dimensional VLSI chip stacks.

    PubMed

    Li, Guoqiang; Huang, Dawei; Yuceturk, Emel; Marchand, Philippe J; Esener, Sadik C; Ozguz, Volkan H; Liu, Yue

    2002-01-10

    We present a demonstration system under the three-dimensional (3D) optoelectronic stacked processor consortium. The processor combines the advantages of optics in global, high-density, high-speed parallel interconnections with the density and computational power of 3D chip stacks. In particular, a compact and scalable optoelectronic switching system with a high bandwidth is designed. The system consists of three silicon chip stacks, each integrated with a single vertical-cavity-surface-emitting-laser-metal-semiconductor-metal detector array and an optical interconnection module. Any input signal at one end stack can be switched through the central crossbar stack to any output channel on the opposite end stack. The crossbar bandwidth is designed to be 256 Gb/s. For the free-space optical interconnection, a novel folded hybrid micro-macro optical system with a concave reflection mirror has been designed. The optics module can provide a high resolution, a large field of view, a high link efficiency, and low optical cross talk. It is also symmetric and modular. Off-the-shelf macro-optical components are used. The concave reflection mirror can significantly improve the image quality and tolerate a large misalignment of the optical components, and it can also compensate for the lateral shift of the chip stacks. Scaling of the macrolens can be used to adjust the interconnection length between the chip stacks or make the system more compact. The components are easy to align, and only passive alignment is required. Optics and electronics are separated until the final assembly step, and the optomechanic module can be removed and replaced. By use of 3D chip stacks, commercially available optical components, and simple passive packaging techniques, it is possible to achieve a high-performance optoelectronic switching system.

  5. 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.

  6. Three-dimensional time-resolved optical mammography of the uncompressed breast

    SciTech Connect

    Enfield, Louise C.; Gibson, Adam P.; Everdell, Nicholas L.; Delpy, David T.; Schweiger, Martin; Arridge, Simon R.; Richardson, Caroline; Keshtgar, Mohammad; Douek, Michael; Hebden, Jeremy C

    2007-06-10

    Optical tomography is being developed as a means of detecting and specifying disease in the adult female breast. We present a series of clinical three-dimensional optical images obtained with a 32-channel time-resolvedsystem and a liquid-coupled interface. Patients place their breasts in a hemispherical cup to whichsources and detectors are coupled, and the remaining space is filled with a highly scattering fluid. Acohort of 38 patients has been scanned, with a variety of benign and malignant lesions. Images show that hypervascularization associated with tumors provides very high contrast due to increased absorption by hemoglobin. Only half of the fibroadenomas scanned could be observed, but of those that could bedetected, all but one revealed an apparent increase in blood volume and a decrease in scatter and oxygen saturation.

  7. Weyl points in three-dimensional optical lattices: synthetic magnetic monopoles in momentum space

    NASA Astrophysics Data System (ADS)

    Buljan, Hrvoje; Dubcek, Tena; Kennedy, Colin; Lu, Ling; Ketterle, Wolfgang; Soljacic, Marin

    2015-05-01

    We show that Hamiltonians with Weyl points can be realized for ultracold atoms using laser-assisted tunneling in three-dimensional (3D) optical lattices. Weyl points are synthetic magnetic monopoles that exhibit a robust, 3D linear dispersion (e.g., see). They are associated with many interesting topological states of matter, such as Weyl semimetals and chiral Weyl fermions. However, Weyl points have yet to be experimentally observed in any system. We show that this elusive goal is well-within experimental reach with an extension of the techniques recently used to obtain the Harper Hamiltonian. We propose using laser assisted tunneling to create a 3D optical lattice, with specifically designed hopping between lattice sites that breaks inversion symmetry. The design leads to creation of four Weyl points in the Brillouin zone of the lattice, which are verified to be monopoles of the synthetic magnetic field. Supported by the Unity through Knowledge Fund (Grant 5/13).

  8. Security authentication with a three-dimensional optical phase code using random forest classifier: an overview

    NASA Astrophysics Data System (ADS)

    Markman, Adam; Carnicer, Artur; Javidi, Bahram

    2017-05-01

    We overview our recent work [1] on utilizing three-dimensional (3D) optical phase codes for object authentication using the random forest classifier. A simple 3D optical phase code (OPC) is generated by combining multiple diffusers and glass slides. This tag is then placed on a quick-response (QR) code, which is a barcode capable of storing information and can be scanned under non-uniform illumination conditions, rotation, and slight degradation. A coherent light source illuminates the OPC and the transmitted light is captured by a CCD to record the unique signature. Feature extraction on the signature is performed and inputted into a pre-trained random-forest classifier for authentication.

  9. Miniaturized optical gyroscope using active three-dimensional vertically coupled resonators

    NASA Astrophysics Data System (ADS)

    Chen, Jiayang; Zhang, Hao; Jin, Junjie; Lin, Jian; Zhao, Long; Bi, Zhuanfang; Huang, Anping; Xiao, Zhisong

    2015-10-01

    We propose and analyze a gyroscope using active three-dimensional vertically coupled resonators (3D-VCRs), which allows for loss compensation, unidirectional propagation, and a larger sensing area while maintaining the same bulk volume. For the ideal uniform case, the minimum detectable rotation rate ΔΩmin of the active 3D-VCR gyroscope can be decreased by above three orders of magnitude after optimization compared with the passive case. The minimal measurable rotation rates of the 3D-VCR gyroscope, the loss-compensated coupled resonator optical waveguide (LC-CROW) gyroscope, and the equivalent resonant waveguide optical gyroscope (RWOG) decrease with a higher number N of the resonators. Finally, it is shown that the uniform active 3D-VCR gyroscope has a better resolution ΔΩmin than the equivalent LC-CROW and RWOG.

  10. Three-dimensional optical coherence elastography by phase-sensitive comparison of C-scans.

    PubMed

    Kennedy, Brendan F; Malheiro, Francisco Gomes; Chin, Lixin; Sampson, David D

    2014-01-01

    We present an acquisition method for optical coherence elastography (OCE) that enables acquisition of three-dimensional elastograms in 5 s, an order of magnitude faster than previously reported. In this method, based on compression elastography, the mechanical load applied to the sample is altered between acquisitions of consecutive optical coherence tomography volume scans (C-scans). The voxel-by-voxel phase difference between the volumes is used to determine the axial displacement and determining the gradient of the axial displacement versus depth gives the local axial strain. We demonstrate sub-100-microstrain sensitivity and high contrast in elastograms, acquired in 5 s, of structured phantoms and freshly excised rat muscle tissue that are comparable in strain sensitivity and dynamic range to our previously reported B-scan-based method. The much higher acquisition speed may expedite the translation of OCE to clinical and in vivo applications.

  11. Toward superfast three-dimensional optical metrology with digital micromirror device platforms

    NASA Astrophysics Data System (ADS)

    Bell, Tyler; Zhang, Song

    2014-11-01

    Decade-long research efforts toward superfast three-dimensional (3-D) shape measurement leveraging the digital micromirror device (DMD) platforms are summarized. Specifically, we will present the following technologies: (1) high-resolution real-time 3-D shape measurement technology that achieves 30 Hz simultaneous 3-D shape acquisition, reconstruction, and display with more than 300,000 points per frame; (2) superfast 3-D optical metrology technology that achieves 3-D measurement at a rate of tens of kilohertz utilizing the binary defocusing method we invented; and (3) the improvement of the binary defocusing technology for superfast and high-accuracy 3-D optical metrology using the DMD platforms. Both principles and experimental results are presented.

  12. Probe of three-dimensional chiral topological insulators in an optical lattice.

    PubMed

    Wang, S-T; Deng, D-L; Duan, L-M

    2014-07-18

    We propose a feasible experimental scheme to realize a three-dimensional chiral topological insulator with cold fermionic atoms in an optical lattice, which is characterized by an integer topological invariant distinct from the conventional Z(2) topological insulators and has a remarkable macroscopic zero-energy flat band. To probe its property, we show that its characteristic surface states--the Dirac cones--can be probed through time-of-flight imaging or Bragg spectroscopy and the flat band can be detected via measurement of the atomic density profile in a weak global trap. The realization of this novel topological phase with a flat band in an optical lattice will provide a unique experimental platform to study the interplay between interaction and topology and open new avenues for application of topological states.

  13. Three-dimensional fuse deposition modeling of tissue-simulating phantom for biomedical optical imaging

    NASA Astrophysics Data System (ADS)

    Dong, Erbao; Zhao, Zuhua; Wang, Minjie; Xie, Yanjun; Li, Shidi; Shao, Pengfei; Cheng, Liuquan; Xu, Ronald X.

    2015-12-01

    Biomedical optical devices are widely used for clinical detection of various tissue anomalies. However, optical measurements have limited accuracy and traceability, partially owing to the lack of effective calibration methods that simulate the actual tissue conditions. To facilitate standardized calibration and performance evaluation of medical optical devices, we develop a three-dimensional fuse deposition modeling (FDM) technique for freeform fabrication of tissue-simulating phantoms. The FDM system uses transparent gel wax as the base material, titanium dioxide (TiO2) powder as the scattering ingredient, and graphite powder as the absorption ingredient. The ingredients are preheated, mixed, and deposited at the designated ratios layer-by-layer to simulate tissue structural and optical heterogeneities. By printing the sections of human brain model based on magnetic resonance images, we demonstrate the capability for simulating tissue structural heterogeneities. By measuring optical properties of multilayered phantoms and comparing with numerical simulation, we demonstrate the feasibility for simulating tissue optical properties. By creating a rat head phantom with embedded vasculature, we demonstrate the potential for mimicking physiologic processes of a living system.

  14. Three-dimensional fuse deposition modeling of tissue-simulating phantom for biomedical optical imaging.

    PubMed

    Dong, Erbao; Zhao, Zuhua; Wang, Minjie; Xie, Yanjun; Li, Shidi; Shao, Pengfei; Cheng, Liuquan; Xu, Ronald X

    2015-01-01

    Biomedical optical devices are widely used for clinical detection of various tissue anomalies. However, optical measurements have limited accuracy and traceability, partially owing to the lack of effective calibration methods that simulate the actual tissue conditions. To facilitate standardized calibration and performance evaluation of medical optical devices, we develop a three-dimensional fuse deposition modeling (FDM) technique for freeform fabrication of tissue-simulating phantoms. The FDM system uses transparent gel wax as the base material, titanium dioxide (TiO2 ) powder as the scattering ingredient, and graphite powder as the absorption ingredient. The ingredients are preheated, mixed, and deposited at the designated ratios layer-by-layer to simulate tissue structural and optical heterogeneities. By printing the sections of human brain model based on magnetic resonance images, we demonstrate the capability for simulating tissue structural heterogeneities. By measuring optical properties of multilayered phantoms and comparing with numerical simulation, we demonstrate the feasibility for simulating tissue optical properties. By creating a rat head phantom with embedded vasculature, we demonstrate the potential for mimicking physiologic processes of a living system.

  15. Extracting Surface Activation Time from the Optically Recorded Action Potential in Three-Dimensional Myocardium

    PubMed Central

    Walton, Richard D.; Smith, Rebecca M.; Mitrea, Bogdan G.; White, Edward; Bernus, Olivier; Pertsov, Arkady M.

    2012-01-01

    Optical mapping has become an indispensible tool for studying cardiac electrical activity. However, due to the three-dimensional nature of the optical signal, the optical upstroke is significantly longer than the electrical upstroke. This raises the issue of how to accurately determine the activation time on the epicardial surface. The purpose of this study was to establish a link between the optical upstroke and exact surface activation time using computer simulations, with subsequent validation by a combination of microelectrode recordings and optical mapping experiments. To simulate wave propagation and associated optical signals, we used a hybrid electro-optical model. We found that the time of the surface electrical activation (tE) within the accuracy of our simulations coincided with the maximal slope of the optical upstroke (tF∗) for a broad range of optical attenuation lengths. This was not the case when the activation time was determined at 50% amplitude (tF50) of the optical upstroke. The validation experiments were conducted in isolated Langendorff-perfused rat hearts and coronary-perfused pig left ventricles stained with either di-4-ANEPPS or the near-infrared dye di-4-ANBDQBS. We found that tF∗ was a more accurate measure of tE than was tF50 in all experimental settings tested (P = 0.0002). Using tF∗ instead of tF50 produced the most significant improvement in measurements of the conduction anisotropy and the transmural conduction time in pig ventricles. PMID:22225795

  16. A fuzzy-logic antiswing controller for three-dimensional overhead cranes.

    PubMed

    Cho, Sung-Kun; Lee, Ho-Hoon

    2002-04-01

    In this paper, a new fuzzy antiswing control scheme is proposed for a three-dimensional overhead crane. The proposed control consists of a position servo control and a fuzzy-logic control. The position servo control is used to control crane position and rope length, and the fuzzy-logic control is used to suppress load swing. The proposed control guarantees not only prompt suppression of load swing but also accurate control of crane position and rope length for simultaneous travel, traverse, and hoisting motions of the crane. Furthermore, the proposed control provides practical gain tuning criteria for easy application. The effectiveness of the proposed control is shown by experiments with a three-dimensional prototype overhead crane.

  17. Mapping of photoreceptor dysfunction using high resolution three-dimensional spectral optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Sikorski, B. L.; Szkulmowski, M.; Kałużny, J. J.; Bajraszewski, T.; Kowalczyk, A.; Wojtkowski, M.

    2008-02-01

    The ability to obtain reliable information on functional status of photoreceptor layer is essential for assessing vision impairment in patients with macular diseases. The reconstruction of three-dimensional retinal structure in vivo using Spectral Optical Coherence Tomography (Spectral OCT) became possible with a recent progress of the OCT field. Three-dimensional data collected by Spectral OCT devices comprise information on light intensity back-reflected from the junction between photoreceptor outer and inner segments (IS/OS) and thus can be used for evaluating photoreceptors impairment. In this paper, we introduced so called Spectral OCT reflectivity maps - a new method of selecting and displaying the spatial distribution of reflectivity of individual retinal layers. We analyzed the reflectivity of the IS/OS layer in various macular diseases. We have measured eyes of 49 patients with photoreceptor dysfunction in course of age-related macular degeneration, macular holes, central serous chorioretinopathy, acute zonal occult outer retinopathy, multiple evanescent white dot syndrome, acute posterior multifocal placoid pigment epitheliopathy, drug-induced retinopathy and congenital disorders.

  18. Three-dimensional Optical Coherence Tomography Imaging of Retinal Sheet Implants in Live Rats

    PubMed Central

    Seiler, Magdalene J.; Rao, Bin; Aramant, Robert B.; Yu, Lingfeng; Wang, Qiang; Kitayama, Eric; Pham, Sylvia; Yan, Fengrong; Chen, Zhongping; Keirstead, Hans S.

    2010-01-01

    Purpose To obtain three-dimensional images from retinal transplants in live animals and evaluate the placement and structural quality of the transplants. Methods Donor retinal sheets were isolated from E19 fetuses of transgenic rats expressing human alkaline phosphatase (hPAP), and transplanted to the subretinal space of 19–56 d old S334ter-3 rat recipients with fast retinal degeneration (average age at surgery 32d). A total of 143 rats were imaged 1 day – 2.8 months after surgery, using a Fourier domain optical coherence tomography (FDOCT) system, with an axial resolution of 3.5 micron. The CCD A-line integration time was set at 200 μs for better visualization of degenerated retina. After targeting the transplant area, 139 or 199 consecutive slices were scanned. Projection images and movies of the retinal transplant area were computed and later compared with histology. Results OCT scans identified 137 of 141 transplants as a thickening of the degenerated retina. OCT indicated the laminar structure of the transplants and surgical defects, such as RPE/choroid damage with an accuracy rate between 83 and 99%. Three-dimensional projections showed the transplant position in the retina in relation to the optic disc. Histology of transplants by hPAP and hematoxylin-eosin staining was correlated with the OCT results. Conclusions Optical Coherence Tomography is an excellent tool to image retinal layers in a live rat. This procedure helps to evaluate the placement and quality of the transplants in the living eye. PMID:20219535

  19. Three-Dimensional High-Resolution Optical/X-Ray Stereoscopic Tracking Velocimetry

    NASA Technical Reports Server (NTRS)

    Cha, Soyoung S.; Ramachandran, Narayanan

    2004-01-01

    Measurement of three-dimensional (3-D) three-component velocity fields is of great importance in a variety of research and industrial applications for understanding materials processing, fluid physics, and strain/displacement measurements. The 3-D experiments in these fields most likely inhibit the use of conventional techniques, which are based only on planar and optically-transparent-field observation. Here, we briefly review the current status of 3-D diagnostics for motion/velocity detection, for both optical and x-ray systems. As an initial step for providing 3-D capabilities, we nave developed stereoscopic tracking velocimetry (STV) to measure 3-D flow/deformation through optical observation. The STV is advantageous in system simplicity, for continually observing 3- D phenomena in near real-time. In an effort to enhance the data processing through automation and to avoid the confusion in tracking numerous markers or particles, artificial neural networks are employed to incorporate human intelligence. Our initial optical investigations have proven the STV to be a very viable candidate for reliably measuring 3-D flow motions. With previous activities are focused on improving the processing efficiency, overall accuracy, and automation based on the optical system, the current efforts is directed to the concurrent expansion to the x-ray system for broader experimental applications.

  20. Three-Dimensional High-Resolution Optical/X-Ray Stereoscopic Tracking Velocimetry

    NASA Technical Reports Server (NTRS)

    Cha, Soyoung S.; Ramachandran, Naryanan

    2005-01-01

    Measurement of three-dimensional (3-D) three-component velocity fields is of great importance in a variety of research and industrial applications for understanding materials processing, fluid physics, and strain/displacement measurements. The 3-D experiments in these fields most likely inhibit the use of conventional techniques, which are based only on planar and optically-transparent-field observation. Here, we briefly review the current status of 3-D diagnostics for motion/velocity detection, for both optical and x-ray systems. As an initial step for providing 3-D capabilities, we have developed stereoscopic tracking velocimetry (STV) to measure 3-D flow/deformation through optical observation. The STV is advantageous in system simplicity, for continually observing 3-D phenomena in near real-time. In an effort to enhance the data processing through automation and to avoid the confusion in tracking numerous markers or particles, artificial neural networks are employed to incorporate human intelligence. Our initial optical investigations have proven the STV to be a very viable candidate for reliably measuring 3-D flow motions. With previous activities focused on improving the processing efficiency, overall accuracy, and automation based on the optical system, the current efforts is directed to the concurrent expansion to the x-ray system for broader experimental applications.

  1. Three-Dimensional High-Resolution Optical/X-Ray Stereoscopic Tracking Velocimetry

    NASA Technical Reports Server (NTRS)

    Cha, Soyoung S.; Ramachandran, Narayanan

    2004-01-01

    Measurement of three-dimensional (3-D) three-component velocity fields is of great importance in a variety of research and industrial applications for understanding materials processing, fluid physics, and strain/displacement measurements. The 3-D experiments in these fields most likely inhibit the use of conventional techniques, which are based only on planar and optically-transparent-field observation. Here, we briefly review the current status of 3-D diagnostics for motion/velocity detection, for both optical and x-ray systems. As an initial step for providing 3-D capabilities, we nave developed stereoscopic tracking velocimetry (STV) to measure 3-D flow/deformation through optical observation. The STV is advantageous in system simplicity, for continually observing 3- D phenomena in near real-time. In an effort to enhance the data processing through automation and to avoid the confusion in tracking numerous markers or particles, artificial neural networks are employed to incorporate human intelligence. Our initial optical investigations have proven the STV to be a very viable candidate for reliably measuring 3-D flow motions. With previous activities are focused on improving the processing efficiency, overall accuracy, and automation based on the optical system, the current efforts is directed to the concurrent expansion to the x-ray system for broader experimental applications.

  2. Three-Dimensional Electron Optics Model Developed for Traveling-Wave Tubes

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.

    2000-01-01

    A three-dimensional traveling-wave tube (TWT) electron beam optics model including periodic permanent magnet (PPM) focusing has been developed at the NASA Glenn Research Center at Lewis Field. This accurate model allows a TWT designer to develop a focusing structure while reducing the expensive and time-consuming task of building the TWT and hot-testing it (with the electron beam). In addition, the model allows, for the first time, an investigation of the effect on TWT operation of the important azimuthally asymmetric features of the focusing stack. The TWT is a vacuum device that amplifies signals by transferring energy from an electron beam to a radiofrequency (RF) signal. A critically important component is the focusing structure, which keeps the electron beam from diverging and intercepting the RF slow wave circuit. Such an interception can result in excessive circuit heating and decreased efficiency, whereas excessive growth in the beam diameter can lead to backward wave oscillations and premature saturation, indicating a serious reduction in tube performance. The most commonly used focusing structure is the PPM stack, which consists of a sequence of cylindrical iron pole pieces and opposite-polarity magnets. Typically, two-dimensional electron optics codes are used in the design of magnetic focusing devices. In general, these codes track the beam from the gun downstream by solving equations of motion for the electron beam in static-electric and magnetic fields in an azimuthally symmetric structure. Because these two-dimensional codes cannot adequately simulate a number of important effects, the simulation code MAFIA (solution of Maxwell's equations by the Finite-Integration-Algorithm) was used at Glenn to develop a three-dimensional electron optics model. First, a PPM stack was modeled in three dimensions. Then, the fields obtained using the magnetostatic solver were loaded into a particle-in-cell solver where the fully three-dimensional behavior of the beam

  3. Three dimensional time lapse imaging of live cell mitochondria with photothermal optical lock-in optical coherence microscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Sison, Miguel; Chakrabortty, Sabyasachi; Extermann, Jerome; Nahas, Amir; Pache, Christophe; Weil, Tanja; Lasser, Theo

    2016-03-01

    The photothermal optical lock-in optical coherence microscope (poli-OCM) introduced molecular specificity to OCM imaging, which is conventionally, a label-free technique. Here we achieve three-dimensional live cell and mitochondria specific imaging using ~4nm protein-functionalized gold nanoparticles (AuNPs). These nanoparticles do not photobleach and we demonstrate they're suitability for long-term time lapse imaging. We compare the accuracy of labelling with these AuNPs using classical fluorescence confocal imaging with a standard mitochondria specific marker. Furthermore, time lapse poli-OCM imaging every 5 minutes over 1.5 hours period was achieved, revealing the ability for three-dimensional monitoring of mitochondria dynamics.

  4. Three-dimensional optical memory using photoluminescence change in Sm-doped sodium borate glass

    SciTech Connect

    Lim, Jinhyong; Lee, Myeongkyu; Kim, Eunkyoung

    2005-05-09

    The feasibility of three-dimensional (3D) optical memory has been demonstrated by utilizing the photoluminescence (PL) spectrum change in a Sm-doped fluoride glass [K. Miura, J. Qiu, S. Fujiwara, S. Sakasuchi, and K. Hirao, Appl. Phys. Lett. 80 2263 (2002)]. We here report on a femtosecond laser-induced PL change in a Sm-doped sodium borate glass that is easier to synthesize and its potential application to 3D memory. Irradiation with a femtosecond pulsed laser (800 nm, 1 kHz, 100 fs) induced a PL peak near 682 nm, resulting from the photoreduction of the Sm ions. A multilayer pattern (bit size=1 {mu}m,layer separation=8 {mu}m) formed by femtosecond laser irradiation was read out by a reflection-type fluorescent confocal microscope, which detected the emission at 682 nm as a signal. High-contrast pattern images were obtained without crosstalk.

  5. Quantum corrections in the optical properties of three-dimensional plasmonic metamaterials with subnanometer gaps

    NASA Astrophysics Data System (ADS)

    Yannopapas, Vassilios

    2015-11-01

    We study the effect of the electron tunnelling between two metallic surfaces in the optical response of a three-dimensional plasmonic metamaterial design, namely a square lattice of nanorods containing periodically repeated subnanometer slits. We show, in particular, that due to the interaction of the slits primarily within a single nanorod, the presence of charge tunnelling can modify drastically the surface-plasmon absorbance spectra in the manner of sizeable wavelength shifts and widening of the corresponding peaks, under suitable conditions of light incidence. Our calculations are based on rigorous electrodynamic multiple-scattering calculations incorporating a recently proposed quantum-corrected model [R. Esteban et al., Nat. Commun. 3, (2012) 825] simulating the effect of charge tunnelling between metal surfaces.

  6. Optical properties of three-dimensional P(St-MAA) photonic crystals on polyester fabrics

    NASA Astrophysics Data System (ADS)

    Liu, Guojin; Zhou, Lan; Wu, Yujiang; Wang, Cuicui; Fan, Qinguo; Shao, Jianzhong

    2015-04-01

    The three-dimensional (3D) photonic crystals with face-centered cubic (fcc) structure was fabricated on polyester fabrics, a kind of soft textile materials quite different from the conventional solid substrates, by gravitational sedimentation self-assembly of monodisperse P(St-MAA) colloidal microspheres. The optical properties of structural colors on polyester fabrics were investigated and the position of photonic band gap was characterized. The results showed that the color-tuning ways of the structural colors from photonic crystals were in accordance with Bragg's law and could be modulated by the size of P(St-MAA) colloidal microspheres and the viewing angles. The L∗a∗b∗ values of the structural colors generated from the assembled polyester fabrics were in agreement with their reflectance spectra. The photonic band gap position of photonic crystals on polyester fabrics could be consistently confirmed by reflectance and transmittance spectra.

  7. Simulation of radiation effects on three-dimensional computer optical memories

    NASA Technical Reports Server (NTRS)

    Moscovitch, M.; Emfietzoglou, D.

    1997-01-01

    A model was developed to simulate the effects of heavy charged-particle (HCP) radiation on the information stored in three-dimensional computer optical memories. The model is based on (i) the HCP track radial dose distribution, (ii) the spatial and temporal distribution of temperature in the track, (iii) the matrix-specific radiation-induced changes that will affect the response, and (iv) the kinetics of transition of photochromic molecules from the colored to the colorless isomeric form (bit flip). It is shown that information stored in a volume of several nanometers radius around the particle's track axis may be lost. The magnitude of the effect is dependent on the particle's track structure.

  8. Three-dimensional full wave model of image formation in optical coherence tomography.

    PubMed

    Munro, Peter R T

    2016-11-14

    We demonstrate, what we believe to be, the first mathematical model of image formation in optical coherence tomography, based on Maxwell's equations, applicable to general three-dimensional samples. It is highly realistic and represents a significant advance on a previously developed model, which was applicable to two-dimensional samples only. The model employs an electromagnetic description of light, made possible by using the pseudospectral time-domain method for calculating the light scattered by the sample which is represented by a general refractive index distribution. We derive the key theoretical and computational advances required to develop this model. Two examples are given of image formation for which analytic comparisons may be calculated: point scatterers and finite sized spheres. We also provide a more realistic example of C-scan formation when imaging turbid media. We anticipate that this model will be important for various applications in OCT, such as image interpretation and the development of quantitative techniques.

  9. Three-dimensional optical lattice clock with bosonic {sup 88}Sr atoms

    SciTech Connect

    Akatsuka, Tomoya; Takamoto, Masao; Katori, Hidetoshi

    2010-02-15

    We present detailed analyses of our recent experiment on the three-dimensional (3D) optical lattice clock with bosonic {sup 88}Sr atoms in which the collisional frequency shift was suppressed by applying a single-occupancy lattice. Frequency shifts in magnetically induced spectroscopy on the {sup 1}S{sub 0}-{sup 3}P{sub 0} clock transition ({lambda}=698 nm) of {sup 88}Sr were experimentally investigated by referencing a one-dimensional (1D) lattice clock based on spin-polarized {sup 87}Sr atoms. We discuss that the clock stability is limited by the current laser stability as well as the experimental sequence of the clock operation, which may be improved to {sigma}{sub y}({tau})=2x10{sup -16}/{radical}({tau}) by optimizing the cycle time of the clock operation.

  10. Three-dimensional eye motion correction by Lissajous scan optical coherence tomography

    PubMed Central

    Chen, Yiwei; Hong, Young-Joo; Makita, Shuichi; Yasuno, Yoshiaki

    2017-01-01

    A three-dimensional optical coherence tomography imaging method based on Lissajous scanning is presented. This method was designed to correct eye motion in OCT images. A Lissajous scanning pattern, which has a trajectory that frequently overlaps with itself, is adopted as the OCT scanning protocol to obtain measurement data. Eye motion artifacts are then corrected automatically by software. By comparing the images without and with motion correction, we show the effectiveness of our method. We performed an experiment and compared the results obtained by our method with the ground truths to verify its validity. The experimental results showed that our method effectively corrects eye motion artifacts. Furthermore, the sufficient repeatability of our method was confirmed. PMID:28663866

  11. Three-dimensional eye motion correction by Lissajous scan optical coherence tomography.

    PubMed

    Chen, Yiwei; Hong, Young-Joo; Makita, Shuichi; Yasuno, Yoshiaki

    2017-03-01

    A three-dimensional optical coherence tomography imaging method based on Lissajous scanning is presented. This method was designed to correct eye motion in OCT images. A Lissajous scanning pattern, which has a trajectory that frequently overlaps with itself, is adopted as the OCT scanning protocol to obtain measurement data. Eye motion artifacts are then corrected automatically by software. By comparing the images without and with motion correction, we show the effectiveness of our method. We performed an experiment and compared the results obtained by our method with the ground truths to verify its validity. The experimental results showed that our method effectively corrects eye motion artifacts. Furthermore, the sufficient repeatability of our method was confirmed.

  12. Three-dimensional spectral domain optical coherence tomography in chronic exposure to welding arc

    PubMed Central

    Saxena, Sandeep; Mishra, Nibha; Meyer, Carsten H

    2014-01-01

    Three-dimensional spectral domain optical coherence tomography was performed in a 26-year-old man with chronic exposure to welding arc. Advanced macular visualisation provided significant findings of inner segment-ellipsoid zone disruption with the presence of cystoid changes and hyper-reflective material in the area of disruption. The external limiting membrane was intact in both the eyes. C-scan retinal pigment epithelium fit map of the left eye revealed a well-delineated defect whereas the right eye showed a poorly delineated smaller defect. The hyper-reflective material can be hypothesised to originate from the disrupted photoreceptor layer. The hyper-reflective material was more evident in the left eye which could be correlated with more marked diminution of vision and a prominent yellow lesion at the fovea. PMID:24832707

  13. Simulation of radiation effects on three-dimensional computer optical memories.

    PubMed

    Moscovitch, M; Emfietzoglou, D

    1997-01-01

    A model was developed to simulate the effects of heavy charged-particle (HCP) radiation on the information stored in three-dimensional computer optical memories. The model is based on (i) the HCP track radial dose distribution, (ii) the spatial and temporal distribution of temperature in the track, (iii) the matrix-specific radiation-induced changes that will affect the response, and (iv) the kinetics of transition of photochromic molecules from the colored to the colorless isomeric form (bit flip). It is shown that information stored in a volume of several nanometers radius around the particle's track axis may be lost. The magnitude of the effect is dependent on the particle's track structure.

  14. Spatial correlations and optical properties in three-dimensional deterministic aperiodic structures

    PubMed Central

    Renner, Michael; Freymann, Georg von

    2015-01-01

    Photonic systems have strongly varying optical properties depending on the spatial correlations present in a given realization. In photonic crystals the correlations are spatially periodic forming Bravais lattices whereas the building blocks of an amorphous medium are randomly distributed without any long-range order. In this manuscript we study the optical properties of so-called deterministic aperiodic structures which fill the gap between the aforementioned two limiting cases. Within this group we vary the spectrum of the spatial correlations from being pure-point over singularly-continuous to absolutely-continuous. The desired correlations are created in direct-laser written three-dimensional polymer structures using one construction principle which allows us to attribute the optical behaviour solely to the encoded spectrum. Infrared reflection measurements reveal the characteristic response of each spectral type verifying the successful fabrication of large deterministic aperiodic structures. To prove the presence of the correlations in all directions we perform transmission experiments parallel to the substrate by means of micro-optical mirrors placed next to the structures. Transport measurements reveal a strong dependence of the effective beam width at the output facet on the encoded lattice type. Finally, we reproduce the lattice type dependent transport behavior in numerical calculations ruling out extrinsic experimental reasons for these findings. PMID:26268153

  15. All-optical dynamical Casimir effect in a three-dimensional terahertz photonic band gap

    NASA Astrophysics Data System (ADS)

    Hagenmüller, David

    2016-06-01

    We identify an architecture for the observation of all-optical dynamical Casimir effect in realistic experimental conditions. We suggest that by integrating quantum wells in a three-dimensional (3D) photonic band-gap material made out of large-scale (˜200 -μ m ) germanium logs, it is possible to achieve ultrastrong light-matter coupling at terahertz frequencies for the cyclotron transition of a two-dimensional electron gas interacting with long-lived optical modes, in which vacuum Rabi splitting is comparable to the Landau level spacing. When a short, intense electromagnetic transient of duration ˜250 fs and carrying a peak magnetic field ˜5 T is applied to the structure, the cyclotron transition can be suddenly tuned on resonance with a desired photon mode, switching on the light-matter interaction and leading to a Casimir radiation emitted parallel to the quantum well plane. The radiation spectrum consists of sharp peaks with frequencies coinciding with engineered optical modes within the 3D photonic band gap, and its characteristics are extremely robust to the nonradiative damping which can be large in our system. Furthermore, the absence of continuum with associated low-energy excitations for both electromagnetic and electronic quantum states can prevent the rapid absorption of the photon flux which is likely to occur in other proposals for all-optical dynamical Casimir effect.

  16. Three-dimensional two-photon laser fabrication for metals, polymers, and magneto-optical materials

    NASA Astrophysics Data System (ADS)

    Tanaka, Takuo; Ishikawa, Atsushi; Amemiya, Tomohiro

    2015-03-01

    The three-dimensional (3D) two-photon laser fabrication techniques for metal, polymer, and magneto-optical structures are presented. Two-photon-induced reduction of metal complex ions was developed to create 3D metal micro/nano structures. Owing to the inhibition of unwanted growth of metal nano crystals using surfactant molecules, we have successfully improved the spatial resolution of fabricated metal structures down to 100 nm in linewidth. Arbitrary shaped 3D silver structures with high electric conductivity were fabricated. Two-photon-induced photopolymerization technique has been applied for the photonic wire bonding. We have demonstrated the optical interconnection of III-V based DFB lasers and photo detectors by polymer wires with optical coupling loss less than 0.3dB. We also applied two-photon laser irradiation technique for the modification of the magnetic properties of cerium-substituted yttrium iron garnet crystal (CexY3-xFe5O12: Ce:YIG). A Ce:YIG layer was epitaxially-grown on a monomagnetic garnet (<111>-SGGG) substrate. 3D fs laser scanning in the Ce:YIG layer creates the micrometer patterns of both refractive index and magnetic properties change of the crystal. We demonstrated the micro/nanometer scale patterning of both optical and magnetic properties in the Ce:YIG crystal.

  17. Influence on open-circuit voltage by optical heterogeneity in three-dimensional organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Wang, Mingjun; Huang, Huihui; Nie, Wanyi; Li, Qi; Peterson, Eric D.; Coffin, Robert; Fang, Guojia; Carroll, David L.

    2011-08-01

    In three-dimensional photovoltaic architectures, heterogeneous optical intensity distributions throughout the structure may generally lead to modifications to the short circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF). In this work an equivalent circuit model has been developed to examine the impact on Voc by heterogeneous and homogeneous internal illumination. The model has been tested against data from planar cell and tube-based solar cells that utilize poly-(3-hexylthiophene): phenyl C61 butyric acid methyl ester (P3HT:PCBM). This has further been extended to predict optimum optical design for tube-based geometries in which organic photoconversion materials have been applied in both fabrication conditions. The result is that for such geometries to provide the best overall optical confinement and best power conversion performance, aspect ratios must be between 1 and 5. The resulting structure leads to best light capture together with best overall internal partitioning of optical power to achieve the highest possible Voc.

  18. Three dimensional fabrication of optical waveguiding elements for on-chip integration

    NASA Astrophysics Data System (ADS)

    Parsi Sreenivas, V. V.; Bülters, M.; Schröder, M.; Bergmann, R. B.

    2014-05-01

    We present micro polymer optical waveguide elements fabricated using femtosecond laser and two-photon absorption (TPA) process. The POWs are constructed by tightly focusing a laser beam in SU-8 based resists transparent to the laser wavelength for single-photon absorption. The TPA process enables the patterning of the resist in three dimensions at a resolution of 100-200 nm, which provides a high degree of freedom for POW designs. Using this technology, we provide a novel approach to fabricate Three dimensional Polymer Optical Waveguides (3D-POW) and coupling with single mode fibers in the visible wavelength regions. Our research is also focused on fabricating passive micro optical elements such as splitters, combiners and simple logical gates. For this reason we are aiming to achieve optimum coupling efficiency between the 3D-POW and fibers. The technology also facilitates 3D-POW fabrication independent of the substrate material. We present these fabrication techniques and designs, along with supporting numerical simulations and its transmission properties. With a length of 270 μm and polymer core diameter of 9 μm with air cladding, the waveguides possess a total loss of 12 dB. This value also includes the external in and out mode coupling and in continuously being improved upon by design optimization and simulations. We verify the overall feasibility of the design and coupling mechanisms that can be exploited to execute waveguide based optical functions such as filtering and logical operations.

  19. Three-dimensional extremely-short optical pulses in carbon nanotube arrays in the presence of an external magnetic field

    NASA Astrophysics Data System (ADS)

    Zhukov, Alexander V.; Bouffanais, Roland; Belonenko, Mikhail B.; Galkina, Elena N.

    2016-12-01

    In this paper, we study the behavior of three-dimensional extremely-short optical pulses propagating in a system made of carbon nanotubes in the presence of an external magnetic field applied perpendicular both to the nanotube axis and to the direction of propagation of the pulse. The evolution of the electromagnetic field is classically derived on the basis of the Maxwell’s equations. The electronic system of carbon nanotubes is considered in the low-temperature approximation. Our analysis reveals the novel and unique ability of controlling the shape of propagating short optical pulses by tuning the intensity of the applied magnetic field. This effect paves the way for the possible development of innovative applications in optoelectronics.

  20. Three-dimensional optical sectioning by scanning confocal electron microscopy with a stage-scanning system.

    PubMed

    Hashimoto, Ayako; Shimojo, Masayuki; Mitsuishi, Kazutaka; Takeguchi, Masaki

    2010-06-01

    We evaluated the depth resolution of annular dark-field (ADF) scanning confocal electron microscopy (SCEM) with a stage-scanning system by observation of nanoparticles. ADF-SCEM is a three-dimensional (3D) imaging technique that we recently proposed. An ADF-SCEM instrument involves a pinhole aperture before a detector for rejecting electrons from the out-of-focal plane in a specimen and an annular aperture under the specimen for collecting only scattered electrons. The stage-scanning system enables us to directly obtain optical slice images perpendicular and parallel to an optical axis at a desired position. In particular, the parallel slices visualize the elongation of nanoparticles along the optical axis, which depends on the depth resolution. ADF-SCEM effectively reduced the elongation length of the nanoparticles sufficiently to demonstrate depth sectioning, in comparison with scanning transmission electron microscopy and bright-field SCEM. The experimentally obtained length was nearly equal to the theoretically estimated one from the probe size considering the experimental conditions. Furthermore, we applied this ADF-SCEM technique to analysis of the 3D position of catalytic nanoparticles on carbon nanostructures.

  1. 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.

  2. Responses of Ventral Posterior Thalamus Neurons to Three-Dimensional Vestibular and Optic Flow Stimulation

    PubMed Central

    Meng, Hui

    2010-01-01

    Multisensory neurons tuned to both vestibular and visual motion (optic flow) signals are found in several cortical areas in the dorsal visual stream. Here we examine whether such convergence occurs subcortically in the macaque thalamus. We searched the ventral posterior nuclei, including the anterior pulvinar, as well as the ventro-lateral and ventral posterior lateral nuclei, areas that receive vestibular signals from brain stem and deep cerebellar nuclei. Approximately a quarter of cells responded to three-dimensional (3D) translational and/or rotational motion. More than half of the responsive cells were convergent, thus responded during both rotation and translation. The preferred axes of translation/rotation were distributed throughout 3D space. The majority of the neurons were excited, but some were inhibited, during rotation/translation in darkness. Only a couple of neurons were multisensory being tuned to both vestibular and optic flow stimuli. We conclude that multisensory vestibular/optic flow neurons, which are commonly found in cortical visual and visuomotor areas, are rare in the ventral posterior thalamus. PMID:19955294

  3. Assembly, Structure and Optical Response of Three-Dimensional Dynamically Tunable Multicomponent Superlattices

    SciTech Connect

    Xiong, H.; Sfeir, M; Gang, O

    2010-01-01

    We report the successful fabrication of optically active three-dimensional (3D) superlattices that incorporate DNA-encoded components, metallic nanoparticles, and molecular chromophores in well-defined positions. A DNA linker with three distinct binding sites serves as an assembly agent and dynamically tunable structural element for the superlattice. Using small angle X-ray scattering we have revealed the organization of particle-chromophore 3D arrays and monitored their reversible contractions and expansions that were modulated by ionic strength changes. As the distance between the molecular chromophores and plasmonic nanoparticles in the superlattice was regulated in situ, we were able to uncover the relationship between experimentally determined structure and optical response of the system. This dynamical tunability of superlattice results in a dramatic optical response: nearly a three times change of emission rate of the chromophore. The evolution of lifetime with structural changes reasonably agrees with the calculations based on a cumulitative coupling of chromophores with metallic nanoparticles in different coordination shells.

  4. Assembly, Structure and Optical Response of Three-Dimensional Dynamically Tunable Multicomponent Superlattices

    SciTech Connect

    Gang, O.; Xiong, H.; Sfeir, M

    2010-11-01

    We report the successful fabrication of optically active three-dimensional (3D) superlattices that incorporate DNA-encoded components, metallic nanoparticles, and molecular chromophores in well-defined positions. A DNA linker with three distinct binding sites serves as an assembly agent and dynamically tunable structural element for the superlattice. Using small angle X-ray scattering we have revealed the organization of particle-chromophore 3D arrays and monitored their reversible contractions and expansions that were modulated by ionic strength changes. As the distance between the molecular chromophores and plasmonic nanoparticles in the superlattice was regulated in situ, we were able to uncover the relationship between experimentally determined structure and optical response of the system. This dynamical tunability of superlattice results in a dramatic optical response: nearly a three times change of emission rate of the chromophore. The evolution of lifetime with structural changes reasonably agrees with the calculations based on a cumulitative coupling of chromophores with metallic nanoparticles in different coordination shells.

  5. Assembly, structure and optical response of three-dimensional dynamically tunable multicomponent superlattices.

    PubMed

    Xiong, Huiming; Sfeir, Matthew Y; Gang, Oleg

    2010-11-10

    We report the successful fabrication of optically active three-dimensional (3D) superlattices that incorporate DNA-encoded components, metallic nanoparticles, and molecular chromophores in well-defined positions. A DNA linker with three distinct binding sites serves as an assembly agent and dynamically tunable structural element for the superlattice. Using small angle X-ray scattering we have revealed the organization of particle-chromophore 3D arrays and monitored their reversible contractions and expansions that were modulated by ionic strength changes. As the distance between the molecular chromophores and plasmonic nanoparticles in the superlattice was regulated in situ, we were able to uncover the relationship between experimentally determined structure and optical response of the system. This dynamical tunability of superlattice results in a dramatic optical response: nearly a three times change of emission rate of the chromophore. The evolution of lifetime with structural changes reasonably agrees with the calculations based on a cumulitative coupling of chromophores with metallic nanoparticles in different coordination shells.

  6. Structure of modes of a smoothly irregular integrated-optical four-layer three-dimensional waveguide

    SciTech Connect

    Egorov, Alexander A; Sevast'yanov, L A

    2009-06-30

    The asymptotic method and the method of coupled waves used to study an integrated-optical multilayer three-dimensional waveguide satisfying the conditions of a continuously variable effective refractive index are considered. Three-dimensional fields of smoothly deforming modes of a four-layer integrated-optical waveguide are described analytically. Explicit dependences of the contributions of the first order of smallness to the electric and magnetic field amplitudes of quasi-waveguide modes are obtained. The canonical type of quasi-wave equations describing the structure of quasi-TE and quasi-TM modes in a smoothly irregular four-layer integrated-optical three-dimensional waveguide is presented for the asymptotic method. By using the perturbation theory, shifts of complex propagation constants are obtained in an explicit form for these modes. The elaborated theory can be used to analyse structures from dielectric, magnetic and metamaterials in a rather broad wavelength range of electromagnetic waves. (waveguides. optical fibres)

  7. Potential-based methodology for active sound control in three dimensional settings.

    PubMed

    Lim, H; Utyuzhnikov, S V; Lam, Y W; Kelly, L

    2014-09-01

    This paper extends a potential-based approach to active noise shielding with preservation of wanted sound in three-dimensional settings. The approach, which was described in a previous publication [Lim et al., J. Acoust. Soc. Am. 129(2), 717-725 (2011)], provides several significant advantages over conventional noise control methods. Most significantly, the methodology does not require any information including the characterization of sources, impedance boundary conditions and surrounding medium, and that the methodology automatically differentiates between the wanted and unwanted sound components. The previous publication proved the concept in one-dimensional conditions. In this paper, the approach for more realistic conditions is studied by numerical simulation and experimental validation in three-dimensional cases. The results provide a guideline to the implementation of the active shielding method with practical three-dimensional conditions. Through numerical simulation it is demonstrated that while leaving the wanted sound unchanged, the developed approach offers selective volumetric noise cancellation within a targeted domain. In addition, the method is implemented in a three-dimensional experiment with a white noise source in a semi-anechoic chamber. The experimental study identifies practical difficulties and limitations in the use of the approach for real applications.

  8. Three-dimensional optical tomographic brain imaging in small animals, part 1: hypercapnia.

    PubMed

    Bluestone, A Y; Stewart, M; Lasker, J; Abdoulaev, G S; Hielscher, A H

    2004-01-01

    studies demonstrate the potential and limitations of our diffuse optical imager for visualizing global and focal hemodynamic phenomenon three dimensionally in the brains of small animals.

  9. Measurement of the optical characteristics of electrowetting prism array for three-dimensional display

    NASA Astrophysics Data System (ADS)

    Kim, Yunhee; Choi, Yoon-Sun; Choi, Kyuwhan; Kwon, Yongjoo; Bae, Jungmok; Morozov, Alexander; Lee, Hong-Seok

    2013-03-01

    Recently liquid-based optical devices are emerging as attractive components in three-dimensional (3D) display for its compact structure and fast response time. Among them an electrowetting prism array is one of the promising 3D devices. It steers a beam, which enables to provide corresponding perspectives to observer. For high quality autostereoscopic 3D displays the important factors are the beam steering angle and the beam profile, the optical characteristics. In this paper, we propose a method to measure the optical characteristics of the liquid prism and show experimental results on our prototype electrowetting prism array, which consists of prisms with 200um by 200um size. A modified 4-f system is adopted for the proposed method. It provides two kinds of information of the optical characteristics of the liquid prism at the image plane and at the Fourier plane. First, the proposed measurement setup magnifies the image of the liquid micro prism array so that we can observe the status of the each prism array directly with bare eye and align a mask easily for selecting a prism to be examined at the image plane. Secondly, the steering angle can be calculated by measuring the displacement of the beam at the Fourier plane, where the angular profiles that have important information on the oilwater interface is observed precisely. The principle of the proposed method will be explained, and the measured optical characteristics from experimental results on the liquid prism we fabricated will be provided, which proves the validity of the measurement method.

  10. Towards a three-dimensional network of direct laser written waveguides on a chip for quantum optical experiments (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Landowski, Alexander; Schmidt, Michael; Renner, Michael; von Freymann, Georg; Widera, Artur

    2016-09-01

    Waveguide networks are essential to gain control over photons on a chip-scale level, for applications in, e.g., optical communication, light routing, and even quantum simulation. Quantum simulators on a chip use highly controllable pairs of single photons to shed light onto the role of entanglement in interacting many-body systems. We build three-dimensional waveguide networks on a chip using a commercial system for direct laser writing in a low fluorescent photoresist on a silica substrate and air cladding. Due to our capability to fabricate three-dimensional structures, we use special coupling structures, that enable addressing all input and output ports of our waveguide network through the substrate via one microscope objective simultaneously. Since the photoresist shows low fluorescence for excitation at 532 nm, we will be able to integrate single quantum emitters, such as color centers in diamond, into the waveguide, acting as integrated single quantum system. Here we present our current arc shaped coupling structure, discuss the limits of the single mode-operation of the waveguides and show first beamsplitting devices. We analyze the contributions to the damping in our network, including the bend loss for bend radii smaller than 10 µm.

  11. Boundary control design for extensible marine risers in three dimensional space

    NASA Astrophysics Data System (ADS)

    Do, K. D.

    2017-02-01

    A design of boundary controllers is proposed for (practical) exponential stabilization of extensible marine risers in three-dimensional (3D) space under sea loads. The design removes flaws in existing works. Two Lyapunov-type theorems are developed for study of existence and uniqueness, and stability of nonlinear evolution systems in Hilbert space. These theorems have their potential use in control design and stability analysis for flexible systems including marine risers.

  12. Three-dimensional imaging of artificial fingerprint by optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Larin, Kirill V.; Cheng, Yezeng

    2008-03-01

    Fingerprint recognition is one of the popular used methods of biometrics. However, due to the surface topography limitation, fingerprint recognition scanners are easily been spoofed, e.g. using artificial fingerprint dummies. Thus, biometric fingerprint identification devices need to be more accurate and secure to deal with different fraudulent methods including dummy fingerprints. Previously, we demonstrated that Optical Coherence Tomography (OCT) images revealed the presence of the artificial fingerprints (made from different household materials, such as cement and liquid silicone rubber) at all times, while the artificial fingerprints easily spoofed the commercial fingerprint reader. Also we demonstrated that an analysis of the autocorrelation of the OCT images could be used in automatic recognition systems. Here, we exploited the three-dimensional (3D) imaging of the artificial fingerprint by OCT to generate vivid 3D image for both the artificial fingerprint layer and the real fingerprint layer beneath. With the reconstructed 3D image, it could not only point out whether there exists an artificial material, which is intended to spoof the scanner, above the real finger, but also could provide the hacker's fingerprint. The results of these studies suggested that Optical Coherence Tomography could be a powerful real-time noninvasive method for accurate identification of artificial fingerprints real fingerprints as well.

  13. Three-dimensional modeling of nematic liquid crystal micro-optics structures with complex patterned electrodes

    NASA Astrophysics Data System (ADS)

    Rong, Xing; Kang, Shengwu; Zhang, Xinyu; Ji, An; Xie, Changsheng; Zhang, Tianxu

    2012-11-01

    In this paper, a three-dimensional (3-D) relaxation method is used to model the dynamic response behavior of liquid crystal (LC) directors in LC micro-optics structures with complex patterned electrodes. The method is based on Frank- Oseen continuum elastic theory by using a vectorial representation. This method can deal with liquid crystal structures with arbitrary patterned electrodes, and it is quite computational stability. Different numerical results obtained according the method are as follows: (1) the nematic LC structures with complex patterned electrodes applied by a constant voltage signal, and (2) the nematic LC structures with different thickness of LC layer, and (3) the nematic LC structures with different signal voltage. The typical results include the distribution of LC directors in LC layers, the distribution of electric potential in LC layers, and the distribution of phase retardation. The results show that the method can be used to effectively predict the formation of disclination lines, which has a strong impact on the performance of LC micro-optics structures.

  14. Three-dimensional, distendable bladder phantom for optical coherence tomography and white light cystoscopy

    PubMed Central

    Lurie, Kristen L.; Smith, Gennifer T.; Khan, Saara A.; Liao, Joseph C.; Ellerbee, Audrey K.

    2014-01-01

    Abstract. We describe a combination of fabrication techniques and a general process to construct a three-dimensional (3-D) phantom that mimics the size, macroscale structure, microscale surface topology, subsurface microstructure, optical properties, and functional characteristics of a cancerous bladder. The phantom also includes features that are recognizable in white light (i.e., the visual appearance of blood vessels), making it suitable to emulate the bladder for emerging white light+optical coherence tomography (OCT) cystoscopies and other endoscopic procedures of large, irregularly shaped organs. The fabrication process has broad applicability and can be generalized to OCT phantoms for other tissue types or phantoms for other imaging modalities. To this end, we also enumerate the nuances of applying known fabrication techniques (e.g., spin coating) to contexts (e.g., nonplanar, 3-D shapes) that are essential to establish their generalizability and limitations. We anticipate that this phantom will be immediately useful to evaluate innovative OCT systems and software being developed for longitudinal bladder surveillance and early cancer detection. PMID:24623158

  15. Three-dimensional radiation dosimetry based on optically-stimulated luminescence

    NASA Astrophysics Data System (ADS)

    Sadel, M.; Høye, E. M.; Skyt, P. S.; Muren, L. P.; Petersen, J. B. B.; Balling, P.

    2017-05-01

    A new approach to three-dimensional (3D) dosimetry based on optically-stimulated luminescence (OSL) is presented. By embedding OSL-active particles into a transparent silicone matrix (PDMS), the well-established dosimetric properties of an OSL material are exploited in a 3D-OSL dosimeter. By investigating prototype dosimeters in standard cuvettes in combination with small test samples for OSL readers, it is shown that a sufficient transparency of the 3D-OSL material can be combined with an OSL response giving an estimated >10.000 detected photons in 1 second per 1mm3 voxel of the dosimeter at a dose of 1 Gy. The dose distribution in the 3D-OSL dosimeters can be directly read out optically without the need for subsequent reconstruction by computational inversion algorithms. The dosimeters carry the advantages known from personal-dosimetry use of OSL: the dose distribution following irradiation can be stored with minimal fading for extended periods of time, and dosimeters are reusable as they can be reset, e.g. by an intense (bleaching) light field.

  16. Nonlinear optical microscopy reveals invading endothelial cells anisotropically alter three-dimensional collagen matrices

    SciTech Connect

    Lee, P.-F.; Yeh, Alvin T.; Bayless, Kayla J.

    2009-02-01

    The interactions between endothelial cells (ECs) and the extracellular matrix (ECM) are fundamental in mediating various steps of angiogenesis, including cell adhesion, migration and sprout formation. Here, we used a noninvasive and non-destructive nonlinear optical microscopy (NLOM) technique to optically image endothelial sprouting morphogenesis in three-dimensional (3D) collagen matrices. We simultaneously captured signals from collagen fibers and endothelial cells using second harmonic generation (SHG) and two-photon excited fluorescence (TPF), respectively. Dynamic 3D imaging revealed EC interactions with collagen fibers along with quantifiable alterations in collagen matrix density elicited by EC movement through and morphogenesis within the matrix. Specifically, we observed increased collagen density in the area between bifurcation points of sprouting structures and anisotropic increases in collagen density around the perimeter of lumenal structures, but not advancing sprout tips. Proteinase inhibition studies revealed membrane-associated matrix metalloproteinase were utilized for sprout advancement and lumen expansion. Rho-associated kinase (p160ROCK) inhibition demonstrated that the generation of cell tension increased collagen matrix alterations. This study followed sprouting ECs within a 3D matrix and revealed that the advancing structures recognize and significantly alter their extracellular environment at the periphery of lumens as they progress.

  17. Structural- and optical-property characterization of three-dimensional branched ZnO nanospikes

    SciTech Connect

    Chia, M.Y.; Chiu, W.S.; Daud, S.N.H.; Khiew, P.S.; Radiman, S.; Abd-Shukor, R.; Hamid, M.A.A.

    2015-08-15

    Current study reports the synthesis of three-dimensional (3-D) ZnO nanospikes with anomalous optical property, where zinc stearate is adopted as a safe, common and low-cost precursor that undergoes thermal pyrolysis under non-hydrolytic approach. High resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM) result show that the as-synthesized 3-D ZnO nanospikes are constructed by bundle of nanorods that sprout radially outwards in random orientation. The possible growth mechanism is discussed by referring to the microscopy results. X-ray diffraction (XRD) pattern confirms that the nanospikes are highly crystalline, which existed in hexagonal wurtzite crystal structure. Optical absorption characterization shows that the onset absorption for the nanospikes is slightly red-shifted if compared to commercial ZnO and the corresponding bandgap energy is estimated to be 3.1 eV. The photoluminescene (PL) result of ZnO nanospikes indicate that its optical emission exhibits weak UV emission but very intense visible-light emission that ranged from green- up to red-region. The factors that contributed to the intriguing PL characteristic are discussed. Current finding would offer a versatile synthesis scheme in engineering advanced nanostructures with new design that exhibit congruent optical property. - Graphical abstract: Display Omitted - Highlights: • Pyrolysis of zinc stearate in synthesizing 3-D ZnO nanospikes • ZnO nanospikes possess bundle of nanorods that sprout out from the hexagonal stump • Growth mechanism is deduced to elucidate the morphological evolution from nanobullet to nanospike with branching topology • PL spectrum indicate that the nanospike exhibit prominent visible-light emission that ranged from green- to red-region.

  18. Joint Applied Optics and Chinese Optics Letters feature introduction: digital holography and three-dimensional imaging.

    PubMed

    Poon, Ting-Chung

    2011-12-01

    This feature issue serves as a pilot issue promoting the joint issue of Applied Optics and Chinese Optics Letters. It focuses upon topics of current relevance to the community working in the area of digital holography and 3-D imaging.

  19. Positioning control system of three-dimensional wafer stage of lithography

    NASA Astrophysics Data System (ADS)

    Tian, Peng; Yan, Wei; Yang, Fan; Li, Fanxing; Hu, Song

    2016-10-01

    Three-dimensional wafer stage is an important component of lithography. It is required to high positioning precision and efficiency. The closed-loop positioning control system, that consists of five-phase step motor and grating scale, implements rapid and precision positioning control of the three-dimensional wafer stage. The MCU STC15W4K32S4, which is possession of six independent PWM output channels and the pulse width, period is adjustable, is used to control the three axes. The stepper motor driver and grating scale are subdivided according to the precision of lithography, and grating scale data is transmitted to the computer for display in real time via USB communication. According to the lithography material, mask parameter, incident light intensity, it's able to calculate the speed of Z axis, and then get the value of PWM period based on the mathematical formula of speed and pulse period, finally realize high precision control. Experiments show that the positioning control system of three-dimensional wafer stage can meet the requirement of lithography, the closed-loop system is high stability and precision, strong practicability.

  20. Enhanced photocurrent in thin-film amorphous silicon solar cells via shape controlled three-dimensional nanostructures.

    PubMed

    Hilali, Mohamed M; Yang, Shuqiang; Miller, Mike; Xu, Frank; Banerjee, Sanjay; Sreenivasan, S V

    2012-10-12

    In this paper, we have explored manufacturable approaches to sub-wavelength controlled three-dimensional (3D) nano-patterns with the goal of significantly enhancing the photocurrent in amorphous silicon solar cells. Here we demonstrate efficiency enhancement of about 50% over typical flat a-Si thin-film solar cells, and report an enhancement of 20% in optical absorption over Asahi textured glass by fabricating sub-wavelength nano-patterned a-Si on glass substrates. External quantum efficiency showed superior results for the 3D nano-patterned thin-film solar cells due to enhancement of broadband optical absorption. The results further indicate that this enhanced light trapping is achieved with minimal parasitic absorption losses in the deposited transparent conductive oxide for the nano-patterned substrate thin-film amorphous silicon solar cell configuration. Optical simulations are in good agreement with experimental results, and also show a significant enhancement in optical absorption, quantum efficiency and photocurrent.

  1. Optically induced three-dimensional Penrose-type photonic quasicrystal lattices in iron-doped lithium niobate crystal

    NASA Astrophysics Data System (ADS)

    Jin, Wentao; Xue, Yan Ling

    2014-07-01

    Three-dimensional Penrose-type photonic quasicrystal lattices are optically induced inside an iron-doped lithium niobate photorefractive crystal for the first time using a single multi-pinhole plate. The setup of this method is simple and compact dispense with complex optical adjustment system. Induced Penrose-type photonic quasicrystal lattices are analyzed and verified by plane wave guiding and far field diffraction pattern imaging. The quasicrystal microstructures can be maintained for a long time inside the crystal in a dark room. Other more complex three-dimensional photonic quasicrystal structures can be fabricated with this method by designing the multi-pinhole plate flexibly.

  2. Three-dimensional Segmentation of Retinal Cysts from Spectral-domain Optical Coherence Tomography Images by the Use of Three-dimensional Curvelet Based K-SVD.

    PubMed

    Esmaeili, Mahdad; Dehnavi, Alireza Mehri; Rabbani, Hossein; Hajizadeh, Fedra

    2016-01-01

    This paper presents a new three-dimensional curvelet transform based dictionary learning for automatic segmentation of intraretinal cysts, most relevant prognostic biomarker in neovascular age-related macular degeneration, from 3D spectral-domain optical coherence tomography (SD-OCT) images. In particular, we focus on the Spectralis SD-OCT (Heidelberg Engineering, Heidelberg, Germany) system, and show the applicability of our algorithm in the segmentation of these features. For this purpose, we use recursive Gaussian filter and approximate the corrupted pixels from its surrounding, then in order to enhance the cystoid dark space regions and future noise suppression we introduce a new scheme in dictionary learning and take curvelet transform of filtered image then denoise and modify each noisy coefficients matrix in each scale with predefined initial 3D sparse dictionary. Dark pixels between retinal pigment epithelium and nerve fiber layer that were extracted with graph theory are considered as cystoid spaces. The average dice coefficient for the segmentation of cystoid regions in whole 3D volume and with-in central 3 mm diameter on the MICCAI 2015 OPTIMA Cyst Segmentation Challenge dataset were found to be 0.65 and 0.77, respectively.

  3. Three-dimensional Segmentation of Retinal Cysts from Spectral-domain Optical Coherence Tomography Images by the Use of Three-dimensional Curvelet Based K-SVD

    PubMed Central

    Esmaeili, Mahdad; Dehnavi, Alireza Mehri; Rabbani, Hossein; Hajizadeh, Fedra

    2016-01-01

    This paper presents a new three-dimensional curvelet transform based dictionary learning for automatic segmentation of intraretinal cysts, most relevant prognostic biomarker in neovascular age-related macular degeneration, from 3D spectral-domain optical coherence tomography (SD-OCT) images. In particular, we focus on the Spectralis SD-OCT (Heidelberg Engineering, Heidelberg, Germany) system, and show the applicability of our algorithm in the segmentation of these features. For this purpose, we use recursive Gaussian filter and approximate the corrupted pixels from its surrounding, then in order to enhance the cystoid dark space regions and future noise suppression we introduce a new scheme in dictionary learning and take curvelet transform of filtered image then denoise and modify each noisy coefficients matrix in each scale with predefined initial 3D sparse dictionary. Dark pixels between retinal pigment epithelium and nerve fiber layer that were extracted with graph theory are considered as cystoid spaces. The average dice coefficient for the segmentation of cystoid regions in whole 3D volume and with-in central 3 mm diameter on the MICCAI 2015 OPTIMA Cyst Segmentation Challenge dataset were found to be 0.65 and 0.77, respectively. PMID:27563573

  4. A model for the three-dimensional spacecraft control laboratory experiment

    NASA Technical Reports Server (NTRS)

    Kakad, Yogendra P.

    1991-01-01

    A model for the three-dimensional Spacecraft Control Laboratory Experiment (SCOLE) is developed. The objective behind this method of modelling is to utilize the basic partial differential equations of motion for this distributed parameter system and not to use the modal expansion in developing the model. The final model obtained is in terms of a transfer function matrix which relates the flexible mast parameters like displacement, slope, shear stress, etc. to external forces and moments.

  5. The assessment of orthodontic bonding defects: optical coherence tomography followed by three-dimensional reconstruction

    NASA Astrophysics Data System (ADS)

    Rominu, R.; Sinescu, C.; Rominu, M.; Negrutiu, M.; Petrescu, E.; Pop, D.; Podoleanu, A. Gh.

    2011-10-01

    Orthodontic bonding is a simple yet important procedure that can influence the outcome of treatment in case it is performed incorrectly. An orthodontic treatment shadowed by repeated bonding failures can become unduly long and will decrease patient trust and compliance. Optical coherence tomography has been widely used in ophtalmology but is relatively new to dentistry. Using OCT one can detect aerial inclusions within the orthodontic adhesive or even identify incongruence between the bracket base and the tooth surface. The aim of our study was to identify bonding defects and reconstruct them three-dimensionally in order to be able to characterize them more accurately. We bonded 30 sound human permanent teeth with ceramic orthodontic brackets using a no-mix self-curing orthodontic adhesive. Prior to bonding all teeth were stored in tap water at 4°C and then professionally cleaned with rotary brushes and pumice. The samples were processed by the same person and the rotary brushes were changed after every fifth tooth. All interfaces were investigated by means of OCT and 4 defects were found. Subsequently, the defects were reconstructed threedimensionally using an open-source program. By identifying and reconstructing bonding defects we could assess the quality of the bonding procedure. Since bonding tends to be more accurate in vitro where the environmental conditions are close to ideal, it is probable that defects found in vivo be even greater in number, which leads to the conclusion that this type of investigation is potentially valuable.

  6. Hybrid three-dimensional dual- and broadband optically tunable terahertz metamaterials

    PubMed Central

    Meng, Qinglong; Zhong, Zheqiang; Zhang, Bin

    2017-01-01

    The optically tunable properties of the hybrid three-dimensional (3D) metamaterials with dual- and broadband response frequencies are theoretically investigated in the terahertz spectrum. The planar double-split-ring resonators (DSRRs) and the standup double-split-ring resonators are fabricated on a sapphire substrate, forming a 3D array structures. The bi-anisotropy of the hybrid 3D metamaterials is considered because the stand-up DSRRs are not symmetrical with respect to the electric field vector. Due to the electric and magnetic response realized by the planar and the standup double-split-ring resonators respectively, the dual-band resonance response and the negative refractive index can be achieved. The potential of the phase modulation under photoexcitation is also demonstrated. Further analysis indicates that, photoexcitation of free carriers in the silicon within the capacitive region of the standup DSRRs results in a broad resonance response bandwidth (about 0.47 THz), and also functions as a broadband negative refractive index that roughly lies between 0.80 and 2.01 THz. This tunable metamaterials is proposed for the potential application of electromagnetic wave propagation in terahertz area. PMID:28358357

  7. Investigation of multifocal choroiditis with panuveitis by three-dimensional high-penetration optical coherence tomography.

    PubMed

    Yasuno, Yoshiaki; Okamoto, Fumiki; Kawana, Keisuke; Yatagai, Toyohiko; Oshika, Tetsuro

    2009-07-01

    A single case of multifocal choroiditis with panuveitis (MFCPU) was investigated by a three-dimensional (3-D) high-penetration optical coherence tomography. The HP-OCT is based on a swept-source OCT technology, uses a probe beam with a center wavelength of 1060 nm, and possesses a depth resolution of 10.4 micromin tissue. Two eyes of an MFCPU patient were involved in this study. The eyes were also examined by color fundus photograph, fluorescein angiography (FA), and indocyanine green angiography (ICGA). Findings in these four modalities are comparatively discussed. The OCT scans revealed the following characteristic properties of the lesion sites. Thinning of the retina, destructuring of the retinal layers, and disappearance of the junction of the inner and outer segments of the photoreceptor (IS/OS). Due to the high penetration of this OCT system, the following characteristic properties of the lesions were also observed: localized thinning of the choroid, occlusion of the choroidal vessels, and localized hyper-reflectivity that may represent hyper-pigmentation of the choroid.

  8. Improved three-dimensional Fourier domain optical coherence tomography by index matching in alveolar structures

    NASA Astrophysics Data System (ADS)

    Meissner, Sven; Knels, Lilla; Koch, Edmund

    2009-11-01

    Three-dimensional Fourier domain optical coherence tomography (3-D FDOCT) is used to demonstrate that perfusion fixation with a mixture of glutaraldehyde and paraformaldehyde does not alter the geometry of subpleural lung parenchyma in isolated and perfused rabbit lungs. This is confirmed by simultaneous imaging of lung parenchyma with intravital microscopy. To eliminate the diffraction index interfaces between alveolar pockets and walls, we fill the fixed lungs with ethanol by perfusing with gradually increasing concentrations. This bottom-up filling process leaves no remaining air bubbles in the alveolar structures, thus drastically improving the resolution and penetration depth of 3-D FDOCT imaging. We observe an approximately 18% increase in alveolar area after ethanol filling, likely due in large part to elimination of the air/tissue interfaces. 3-D OCT datasets acquired from ethanol-filled lungs allow segmentation of the ethanol-filled structures, which were formerly air-filled, and 3-D reconstruction of larger areas of subpleural alveolar structures. Our innovative process of filling the lungs with ethanol postperfusion fixation thus enables more accurate quantification of alveolar geometries, a critical component of modeling lung function.

  9. Resonant-state expansion applied to three-dimensional open optical systems

    NASA Astrophysics Data System (ADS)

    Doost, M. Â. B.; Langbein, W.; Muljarov, E. Â. A.

    2014-07-01

    The resonant-state expansion (RSE), a rigorous perturbative method in electrodynamics, is developed for three-dimensional open optical systems. Results are presented using the analytically solvable homogeneous dielectric sphere as unperturbed system. Since any perturbation which breaks the spherical symmetry mixes transverse electric (TE) and transverse magnetic (TM) modes, the RSE is extended here to include TM modes and a zero-frequency pole of the Green's function. We demonstrate the validity of the RSE for TM modes by verifying its convergence towards the exact result for a homogeneous perturbation of the sphere. We then apply the RSE to calculate the modes for a selection of perturbations sequentially reducing the remaining symmetry, given by a change of the dielectric constant of half-sphere and quarter-sphere shape. Since no exact solutions are known for these perturbations, we verify the RSE results by comparing them with the results of state of the art finite element method (FEM) and finite difference in time domain (FDTD) solvers. We find that for the selected perturbations, the RSE provides a significantly higher accuracy than the FEM and FDTD for a given computational effort, demonstrating its potential to supersede presently used methods. We furthermore show that in contrast to presently used methods, the RSE is able to determine the perturbation of a selected group of modes by using a limited basis local to these modes, which can further reduce the computational effort by orders of magnitude.

  10. Automated quantitative assessment of three-dimensional bioprinted hydrogel scaffolds using optical coherence tomography

    PubMed Central

    Wang, Ling; Xu, Mingen; Zhang, LieLie; Zhou, QingQing; Luo, Li

    2016-01-01

    Reconstructing and quantitatively assessing the internal architecture of opaque three-dimensional (3D) bioprinted hydrogel scaffolds is difficult but vital to the improvement of 3D bioprinting techniques and to the fabrication of functional engineered tissues. In this study, swept-source optical coherence tomography was applied to acquire high-resolution images of hydrogel scaffolds. Novel 3D gelatin/alginate hydrogel scaffolds with six different representative architectures were fabricated using our 3D bioprinting system. Both the scaffold material networks and the interconnected flow channel networks were reconstructed through volume rendering and binarisation processing to provide a 3D volumetric view. An image analysis algorithm was developed based on the automatic selection of the spatially-isolated region-of–interest. Via this algorithm, the spatially-resolved morphological parameters including pore size, pore shape, strut size, surface area, porosity, and interconnectivity were quantified precisely. Fabrication defects and differences between the designed and as-produced scaffolds were clearly identified in both 2D and 3D; the locations and dimensions of each of the fabrication defects were also defined. It concludes that this method will be a key tool for non-destructive and quantitative characterization, design optimisation and fabrication refinement of 3D bioprinted hydrogel scaffolds. Furthermore, this method enables investigation into the quantitative relationship between scaffold structure and biological outcome. PMID:27231597

  11. Live-cell multiplane three-dimensional super-resolution optical fluctuation imaging.

    PubMed

    Geissbuehler, Stefan; Sharipov, Azat; Godinat, Aurélien; Bocchio, Noelia L; Sandoz, Patrick A; Huss, Anja; Jensen, Nickels A; Jakobs, Stefan; Enderlein, Jörg; Gisou van der Goot, F; Dubikovskaya, Elena A; Lasser, Theo; Leutenegger, Marcel

    2014-12-18

    Super-resolution optical fluctuation imaging (SOFI) provides an elegant way of overcoming the diffraction limit in all three spatial dimensions by computing higher-order cumulants of image sequences of blinking fluorophores acquired with a classical widefield microscope. Previously, three-dimensional (3D) SOFI has been demonstrated by sequential imaging of multiple depth positions. Here we introduce a multiplexed imaging scheme for the simultaneous acquisition of multiple focal planes. Using 3D cross-cumulants, we show that the depth sampling can be increased. The simultaneous acquisition of multiple focal planes significantly reduces the acquisition time and thus the photobleaching. We demonstrate multiplane 3D SOFI by imaging fluorescently labelled cells over an imaged volume of up to 65 × 65 × 3.5 μm(3) without depth scanning. In particular, we image the 3D network of mitochondria in fixed C2C12 cells immunostained with Alexa 647 fluorophores and the 3D vimentin structure in living Hela cells expressing the fluorescent protein Dreiklang.

  12. Hybrid three-dimensional dual- and broadband optically tunable terahertz metamaterials.

    PubMed

    Meng, Qinglong; Zhong, Zheqiang; Zhang, Bin

    2017-03-30

    The optically tunable properties of the hybrid three-dimensional (3D) metamaterials with dual- and broadband response frequencies are theoretically investigated in the terahertz spectrum. The planar double-split-ring resonators (DSRRs) and the standup double-split-ring resonators are fabricated on a sapphire substrate, forming a 3D array structures. The bi-anisotropy of the hybrid 3D metamaterials is considered because the stand-up DSRRs are not symmetrical with respect to the electric field vector. Due to the electric and magnetic response realized by the planar and the standup double-split-ring resonators respectively, the dual-band resonance response and the negative refractive index can be achieved. The potential of the phase modulation under photoexcitation is also demonstrated. Further analysis indicates that, photoexcitation of free carriers in the silicon within the capacitive region of the standup DSRRs results in a broad resonance response bandwidth (about 0.47 THz), and also functions as a broadband negative refractive index that roughly lies between 0.80 and 2.01 THz. This tunable metamaterials is proposed for the potential application of electromagnetic wave propagation in terahertz area.

  13. Hybrid three-dimensional dual- and broadband optically tunable terahertz metamaterials

    NASA Astrophysics Data System (ADS)

    Meng, Qinglong; Zhong, Zheqiang; Zhang, Bin

    2017-03-01

    The optically tunable properties of the hybrid three-dimensional (3D) metamaterials with dual- and broadband response frequencies are theoretically investigated in the terahertz spectrum. The planar double-split-ring resonators (DSRRs) and the standup double-split-ring resonators are fabricated on a sapphire substrate, forming a 3D array structures. The bi-anisotropy of the hybrid 3D metamaterials is considered because the stand-up DSRRs are not symmetrical with respect to the electric field vector. Due to the electric and magnetic response realized by the planar and the standup double-split-ring resonators respectively, the dual-band resonance response and the negative refractive index can be achieved. The potential of the phase modulation under photoexcitation is also demonstrated. Further analysis indicates that, photoexcitation of free carriers in the silicon within the capacitive region of the standup DSRRs results in a broad resonance response bandwidth (about 0.47 THz), and also functions as a broadband negative refractive index that roughly lies between 0.80 and 2.01 THz. This tunable metamaterials is proposed for the potential application of electromagnetic wave propagation in terahertz area.

  14. The characteristics of three-dimensional skin imaging system by full-colored optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Yang, Bor-Wen; Chan, Li-Ming; Wang, Kai-Cheng

    2009-05-01

    In the present cosmetic market, the skin image obtained from a hand-held camera is two-dimensional (2-D). Due to insufficient penetration, only the skin surface can be detected, and thus phenomena in the dermis cannot be observed. To take the place of the conventional 2D camera, a new hand-held imaging system is proposed for three-dimensional (3-D) skin imaging. Featuring non-invasiveness, optical coherence tomography (OCT) has become one of the popular medical imaging techniques. The dermal images shown in OCT-related reports were mainly single-colored because of the use of a monotonic light source. With three original-colored beams applied in OCT, a full-colored image can be derived for dermatology. The penetration depth of the system ranges from 0.43 to 0.78 mm, sufficient for imaging of main tissues in the dermis. Colorful and non-invasive perspectives of deep dermal structure help to advance skin science, dermatology and cosmetology.

  15. Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue

    NASA Astrophysics Data System (ADS)

    Gaertner, Maria; Cimalla, Peter; Meissner, Sven; Kuebler, Wolfgang M.; Koch, Edmund

    2012-07-01

    Although several strategies exist for a minimal-invasive treatment of patients with lung failure, the mortality rate of acute respiratory distress syndrome still reaches 30% at minimum. This striking number indicates the necessity of understanding lung dynamics on an alveolar level. To investigate the dynamical behavior on a microscale, we used three-dimensional geometrical and functional imaging to observe tissue parameters including alveolar size and length of embedded elastic fibers during ventilation. We established a combined optical coherence tomography (OCT) and confocal fluorescence microscopy system that is able to monitor the distension of alveolar tissue and elastin fibers simultaneously within three dimensions. The OCT system can laterally resolve a 4.9 μm line pair feature and has an approximately 11 μm full-width-half-maximum axial resolution in air. confocal fluorescence microscopy visualizes molecular properties of the tissue with a resolution of 0.75 μm (laterally), and 5.9 μm (axially) via fluorescence detection of the dye sulforhodamine B specifically binding to elastin. For system evaluation, we used a mouse model in situ to perform lung distension by application of different constant pressure values within the physiological regime. Our method enables the investigation of alveolar dynamics by helping to reveal basic processes emerging during artificial ventilation and breathing.

  16. Gold Nanoprobe-Enabled Three-Dimensional Ozone Imaging by Optical Coherence Tomography.

    PubMed

    Jiang, Xueqin; Tang, Peijun; Gao, Panpan; Zhang, Yu Shrike; Yi, Changqing; Zhou, Jianhua

    2017-02-21

    Ozone (O3) would be harmful to human skin for its strong oxidizing property, especially when stratum corneum or corneal epithelium is wounded. Imaging the penetration and distribution of ozone at depth is beneficial for studying the influence of ozone on skin or eyes. Here, we introduced a facile method for three-dimensional (3D) imaging of the penetration of O3 into the anterior chamber of an isolated crucian carp eye by using optical coherence tomography (OCT) combined with gold triangular nanoprisms (GTNPs) as the contrast agent and molecular probe. We illustrated the specific response of GTNPs to ozone and demonstrated that GTNPs can function as an efficient nanoprobe for sensing O3. The stabilities of GTNPs in different biologic solutions, as well as the signal intensity of GTNPs on an OCT imaging system, were investigated. Visualization of 3D penetration and distribution of O3 in the biologic tissue was proved for the first time. The quantitative analysis of O3 diffusion in the anterior chamber of the fish eye revealed a penetration depth of 311 μm within 172 min. Due to the strong scattering, near-infrared extinction band, and easy functionalization of GTNPs, they could further serve as nanoprobes for 3D OCT or multimodal imaging of other molecules or ions in the future.

  17. Real-time three-dimensional Fourier-domain optical coherence tomography video image guided microsurgeries

    NASA Astrophysics Data System (ADS)

    Kang, Jin U.; Huang, Yong; Zhang, Kang; Ibrahim, Zuhaib; Cha, Jaepyeong; Lee, W. P. Andrew; Brandacher, Gerald; Gehlbach, Peter L.

    2012-08-01

    The authors describe the development of an ultrafast three-dimensional (3D) optical coherence tomography (OCT) imaging system that provides real-time intraoperative video images of the surgical site to assist surgeons during microsurgical procedures. This system is based on a full-range complex conjugate free Fourier-domain OCT (FD-OCT). The system was built in a CPU-GPU heterogeneous computing architecture capable of video OCT image processing. The system displays at a maximum speed of 10 volume/s for an image volume size of 160×80×1024 (X×Y×Z) pixels. We have used this system to visualize and guide two prototypical microsurgical maneuvers: microvascular anastomosis of the rat femoral artery and ultramicrovascular isolation of the retinal arterioles of the bovine retina. Our preliminary experiments using 3D-OCT-guided microvascular anastomosis showed optimal visualization of the rat femoral artery (diameter<0.8 mm), instruments, and suture material. Real-time intraoperative guidance helped facilitate precise suture placement due to optimized views of the vessel wall during anastomosis. Using the bovine retina as a model system, we have performed "ultra microvascular" feasibility studies by guiding handheld surgical micro-instruments to isolate retinal arterioles (diameter˜0.1 mm). Isolation of the microvessels was confirmed by successfully passing a suture beneath the vessel in the 3D imaging environment.

  18. High-resolution imaging diagnosis of human fetal membrane by three-dimensional optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ren, Hugang; Avila, Cecilia; Kaplan, Cynthia; Pan, Yingtian

    2011-11-01

    Microscopic chorionic pseudocyst (MCP) arising in the chorion leave of the human fetal membrane (FM) is a clinical precursor for preeclampsia which may progress to fatal medical conditions (e.g., abortion) if left untreated. To examine the utility of three-dimensional (3D) optical coherence tomography (OCT) for noninvasive delineation of the morphology of human fetal membranes and early clinical detection of MCP, 60 human FM specimens were acquired from 10 different subjects undergoing term cesarean delivery for an ex vivo feasibility study. Our results showed that OCT was able to identify the four-layer architectures of human FMs consisting of high-scattering decidua vera (DV, average thickness dDV ~ 92+/-38 μm), low-scattering chorion and trophoblast (CT, dCT ~ 150+/-67 μm), high-scattering subepithelial amnion (A, dA ~ 95+/-36 μm), and low-scattering epithelium (E, dE ~ 29+/-8 μm). Importantly, 3D OCT was able to instantaneously detect MCPs (low scattering due to edema, fluid buildup, vasodilatation) and track (staging) their thicknesses dMCP ranging from 24 to 615 μm. It was also shown that high-frequency ultrasound was able to compliment OCT for detecting more advanced thicker MCPs (e.g., dMCP>615 μm) because of its increased imaging depth.

  19. Three-dimensional reconstruction of active muscle cell segment volume from two-dimensional optical sections

    NASA Astrophysics Data System (ADS)

    Lake, David S.; Griffiths, P. J.; Cecchi, G.; Taylor, Stuart R.

    1999-06-01

    An ultramicroscope coupled to a square-aspect-ratio sensor was used to image the dynamic geometry of live muscle cells. Skeletal muscle cells, dissected from frogs, were suspended in the optical axis and illuminated from one side by a focused slit of white light. The sensor detected light scattered at 90 degrees to the incident beam. Serial cross-sections were acquired as a motorized stage moved the cell through the slit of light. The axial force at right angles to the cross- sections was recorded simultaneously. Cross-sections were aligned by a least-squares fit of their centroids to a straight line, to correct for misalignments between the axes of the microscope, the stage, and the sensor. Three- dimensional volumes were reconstructed from each series and viewed from all directions to locate regions that remained at matching axial positions. The angle of the principal axis and the cross-sectional area were calculated and associated with force recorded concurrently. The cells adjusted their profile and volume to remain stable against turning as contractile force rose and fell, as predicted by the law of conservation of angular momentum.

  20. Three-dimensional reconstructions from optical sections of thick mouse inner ears using confocal microscopy.

    PubMed

    Kopecky, B J; Duncan, J S; Elliott, K L; Fritzsch, B

    2012-12-01

    Three-dimensional (3D) reconstructions of the vertebrate inner ear have provided novel insights into the development of this complex organ. 3D reconstructions enable superior analysis of phenotypic differences between wild type and mutant ears but can result in laborious work when reconstructed from physically sectioned material. Although nondestructive optical sectioning light sheet microscopy may ultimately prove the ideal solution, these technologies are not yet commercially available, or in many instances are not monetarily feasible. Here we introduce a simple technique to image a fluorescently labelled ear at different stages throughout development at high resolution enabling 3D reconstruction of any component of the inner ear using confocal microscopy. We provide a step-by-step manual from tissue preparation to imaging to 3D reconstruction and analysis including a rationale and troubleshooting guide at each step for researchers with different equipment, protocols, and access to resources to successfully incorporate the principles of this method and customize them to their laboratory settings. © 2012 The Authors Journal of Microscopy © 2012 Royal Microscopical Society.

  1. Real-time three-dimensional Fourier-domain optical coherence tomography video image guided microsurgeries

    PubMed Central

    Huang, Yong; Zhang, Kang; Ibrahim, Zuhaib; Cha, Jaepyeong; Lee, W. P. Andrew; Brandacher, Gerald; Gehlbach, Peter L.

    2012-01-01

    Abstract. The authors describe the development of an ultrafast three-dimensional (3D) optical coherence tomography (OCT) imaging system that provides real-time intraoperative video images of the surgical site to assist surgeons during microsurgical procedures. This system is based on a full-range complex conjugate free Fourier-domain OCT (FD-OCT). The system was built in a CPU-GPU heterogeneous computing architecture capable of video OCT image processing. The system displays at a maximum speed of 10  volume/s for an image volume size of 160×80×1024 (X×Y×Z) pixels. We have used this system to visualize and guide two prototypical microsurgical maneuvers: microvascular anastomosis of the rat femoral artery and ultramicrovascular isolation of the retinal arterioles of the bovine retina. Our preliminary experiments using 3D-OCT-guided microvascular anastomosis showed optimal visualization of the rat femoral artery (diameter<0.8  mm), instruments, and suture material. Real-time intraoperative guidance helped facilitate precise suture placement due to optimized views of the vessel wall during anastomosis. Using the bovine retina as a model system, we have performed “ultra microvascular” feasibility studies by guiding handheld surgical micro-instruments to isolate retinal arterioles (diameter∼0.1  mm). Isolation of the microvessels was confirmed by successfully passing a suture beneath the vessel in the 3D imaging environment. PMID:23224164

  2. Three-dimensional imaging of the developing mouse female reproductive organs with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Burton, Jason C.; Wang, Shang; Behringer, Richard R.; Larina, Irina V.

    2016-03-01

    Infertility is a known major health concern and is estimated to impact ~15% of couples in the U.S. The majority of failed pregnancies occur before or during implantation of the fertilized embryo into the uterus. Understanding the mechanisms regulating development by studying mouse reproductive organs could significantly contribute to an improved understanding of normal development of reproductive organs and developmental causes of infertility in humans. Towards this goal, we report a three-dimensional (3D) imaging study of the developing mouse reproductive organs (ovary, oviduct, and uterus) using optical coherence tomography (OCT). In our study, OCT was used for 3D imaging of reproductive organs without exogenous contrast agents and provides micro-scale spatial resolution. Experiments were conducted in vitro on mouse reproductive organs ranging from the embryonic day 14.5 to adult stages. Structural features of the ovary, oviduct, and uterus are presented. Additionally, a comparison with traditional histological analysis is illustrated. These results provide a basis for a wide range of infertility studies in mouse models. Through integration with traditional genetic and molecular biology approaches, this imaging method can improve understanding of ovary, oviduct, and uterus development and function, serving to further contribute to our understanding of fertility and infertility.

  3. Three-Dimensional Simultaneous Arbitrary-Way Orbital Angular Momentum Generator Based on Transformation Optics

    PubMed Central

    Zhang, Chen; Deng, Li; Hong, Wei Jun; Jiang, Wei Xiang; Zhu, Jian Feng; Zhou, Mi; Wang, Ling; Li, Shu Fang; Peng, Biao

    2016-01-01

    In wireless communications, people utilize the technology of diversity against multipath fading, so as to improve the reliability of communication equipment. One of the long-standing problems in diversity antennas is the limited number of diversity in a certain space. In this paper, we provide a solution to this issue by a three-dimensional (3D) simultaneous arbitrary-way orbital angular momentum (OAM) generator (3D SAWOG) based on transformation optics. The proposed 3D SAWOG consists of a metamaterial block and a group of transformation cylinders, by which arbitrary-way planar wavefronts can be converted to helical wavefronts with various topological charges simultaneously. The 2D four-way OAM generator and the 3D SAWOG are analyzed, designed, and simulated. The simulation results validate the performance of a 3D SAWOG successfully, indicating that the proposed model possess a high mode purity and expansibility. The SAWOG can be used as a novel diversity antenna array due to the orthogonal property among different modes, which could provide more degrees of freedom than traditional dual-polarization antennas, further improving the reliability of the communication systems. PMID:27929132

  4. Three-dimensional motion tracking for high-resolution optical microscopy, in vivo.

    PubMed

    Bakalar, M; Schroeder, J L; Pursley, R; Pohida, T J; Glancy, B; Taylor, J; Chess, D; Kellman, P; Xue, H; Balaban, R S

    2012-06-01

    When conducting optical imaging experiments, in vivo, the signal to noise ratio and effective spatial and temporal resolution is fundamentally limited by physiological motion of the tissue. A three-dimensional (3D) motion tracking scheme, using a multiphoton excitation microscope with a resonant galvanometer, (512 × 512 pixels at 33 frames s(-1)) is described to overcome physiological motion, in vivo. The use of commercially available graphical processing units permitted the rapid 3D cross-correlation of sequential volumes to detect displacements and adjust tissue position to track motions in near real-time. Motion phantom tests maintained micron resolution with displacement velocities of up to 200 μm min(-1), well within the drift observed in many biological tissues under physiologically relevant conditions. In vivo experiments on mouse skeletal muscle using the capillary vasculature with luminal dye as a displacement reference revealed an effective and robust method of tracking tissue motion to enable (1) signal averaging over time without compromising resolution, and (2) tracking of cellular regions during a physiological perturbation.

  5. Live-cell multiplane three-dimensional super-resolution optical fluctuation imaging

    NASA Astrophysics Data System (ADS)

    Geissbuehler, Stefan; Sharipov, Azat; Godinat, Aurélien; Bocchio, Noelia L.; Sandoz, Patrick A.; Huss, Anja; Jensen, Nickels A.; Jakobs, Stefan; Enderlein, Jörg; Gisou van der Goot, F.; Dubikovskaya, Elena A.; Lasser, Theo; Leutenegger, Marcel

    2014-12-01

    Super-resolution optical fluctuation imaging (SOFI) provides an elegant way of overcoming the diffraction limit in all three spatial dimensions by computing higher-order cumulants of image sequences of blinking fluorophores acquired with a classical widefield microscope. Previously, three-dimensional (3D) SOFI has been demonstrated by sequential imaging of multiple depth positions. Here we introduce a multiplexed imaging scheme for the simultaneous acquisition of multiple focal planes. Using 3D cross-cumulants, we show that the depth sampling can be increased. The simultaneous acquisition of multiple focal planes significantly reduces the acquisition time and thus the photobleaching. We demonstrate multiplane 3D SOFI by imaging fluorescently labelled cells over an imaged volume of up to 65 × 65 × 3.5 μm3 without depth scanning. In particular, we image the 3D network of mitochondria in fixed C2C12 cells immunostained with Alexa 647 fluorophores and the 3D vimentin structure in living Hela cells expressing the fluorescent protein Dreiklang.

  6. IBSIMU: A three-dimensional simulation software for charged particle optics

    SciTech Connect

    Kalvas, T.; Tarvainen, O.; Ropponen, T.; Steczkiewicz, O.; Aerje, J.; Clark, H.

    2010-02-15

    A general-purpose three-dimensional (3D) simulation code IBSIMU for charged particle optics with space charge is under development at JYFL. The code was originally developed for designing a slit-beam plasma extraction and nanosecond scale chopping for pulsed neutron generator, but has been developed further and has been used for many applications. The code features a nonlinear FDM Poisson's equation solver based on fast stabilized biconjugate gradient method with ILU0 preconditioner for solving electrostatic fields. A generally accepted nonlinear plasma model is used for plasma extraction. Magnetic fields can be imported to the simulations from other programs. The particle trajectories are solved using adaptive Runge-Kutta method. Steady-state and time-dependent problems can be modeled in cylindrical coordinates, two-dimensional (slit) geometry, or full 3D. The code is used via C++ programming language for versatility but it features an interactive easy-to-use postprocessing tool for diagnosing fields and particle trajectories. The open source distribution and public documentation make the code well suited for scientific use. IBSIMU has been used for modeling the 14 GHz ECR ion source extraction and for designing a four-electrode extraction for a 2.45 GHz microwave ion source at Jyvaeskylae. A grid extraction has also been designed for producing large uniform beam for creating conditions similar to solar wind. The code has also been used to design a H{sup -} extraction with electron dumping for the Cyclotron Institute of Texas A and M University.

  7. Three-Dimensional Simultaneous Arbitrary-Way Orbital Angular Momentum Generator Based on Transformation Optics

    NASA Astrophysics Data System (ADS)

    Zhang, Chen; Deng, Li; Hong, Wei Jun; Jiang, Wei Xiang; Zhu, Jian Feng; Zhou, Mi; Wang, Ling; Li, Shu Fang; Peng, Biao

    2016-12-01

    In wireless communications, people utilize the technology of diversity against multipath fading, so as to improve the reliability of communication equipment. One of the long-standing problems in diversity antennas is the limited number of diversity in a certain space. In this paper, we provide a solution to this issue by a three-dimensional (3D) simultaneous arbitrary-way orbital angular momentum (OAM) generator (3D SAWOG) based on transformation optics. The proposed 3D SAWOG consists of a metamaterial block and a group of transformation cylinders, by which arbitrary-way planar wavefronts can be converted to helical wavefronts with various topological charges simultaneously. The 2D four-way OAM generator and the 3D SAWOG are analyzed, designed, and simulated. The simulation results validate the performance of a 3D SAWOG successfully, indicating that the proposed model possess a high mode purity and expansibility. The SAWOG can be used as a novel diversity antenna array due to the orthogonal property among different modes, which could provide more degrees of freedom than traditional dual-polarization antennas, further improving the reliability of the communication systems.

  8. Three-dimensional reconstructions from optical sections of thick mouse inner ears using confocal microscopy

    PubMed Central

    B.J. KOPECKY; J.S. DUNCAN; ELLIOTT, K.L.; FRITZSCH, B.

    2013-01-01

    Summary Three-dimensional (3D) reconstructions of the vertebrate inner ear have provided novel insights into the development of this complex organ. 3D reconstructions enable superior analysis of phenotypic differences between wild type and mutant ears but can result in laborious work when reconstructed from physically sectioned material. Although nondestructive optical sectioning light sheet microscopy may ultimately prove the ideal solution, these technologies are not yet commercially available, or in many instances are not monetarily feasible. Here we introduce a simple technique to image a fluorescently labelled ear at different stages throughout development at high resolution enabling 3D reconstruction of any component of the inner ear using confocal microscopy. We provide a step-by-step manual from tissue preparation to imaging to 3D reconstruction and analysis including a rationale and troubleshooting guide at each step for researchers with different equipment, protocols, and access to resources to successfully incorporate the principles of this method and customize them to their laboratory settings. PMID:23140378

  9. Comparison of three-dimensional optical coherence tomography and high resolution photography for art conservation studies.

    PubMed

    Adler, Desmond C; Stenger, Jens; Gorczynska, Iwona; Lie, Henry; Hensick, Teri; Spronk, Ron; Wolohojian, Stephan; Khandekar, Narayan; Jiang, James Y; Barry, Scott; Cable, Alex E; Huber, Robert; Fujimoto, James G

    2007-11-26

    Gold punchwork and underdrawing in Renaissance panel paintings are analyzed using both three-dimensional swept source / Fourier domain optical coherence tomography (3D-OCT) and high resolution digital photography. 3D-OCT can generate en face images with micrometer-scale resolutions at arbitrary sectioning depths, rejecting out-of-plane light by coherence gating. Therefore 3D-OCT is well suited for analyzing artwork where a surface layer obscures details of interest. 3D-OCT also enables cross-sectional imaging and quantitative measurement of 3D features such as punch depth, which is beneficial for analyzing the tools and techniques used to create works of art. High volumetric imaging speeds are enabled by the use of a Fourier domain mode locked (FDML) laser as the 3D-OCT light source. High resolution infrared (IR) digital photography is shown to be particularly useful for the analysis of underdrawing, where the materials used for the underdrawing and paint layers have significantly different IR absrption properties. In general, 3D-OCT provides a more flexible and comprehensive analysis of artwork than high resolution photography, but also requires more complex instrumentation and data analysis.

  10. Bone tissue engineering therapeutics: controlled drug delivery in three-dimensional scaffolds

    PubMed Central

    Mouriño, Viviana; Boccaccini, Aldo R.

    2010-01-01

    This paper provides an extensive overview of published studies on the development and applications of three-dimensional bone tissue engineering (TE) scaffolds with potential capability for the controlled delivery of therapeutic drugs. Typical drugs considered include gentamicin and other antibiotics generally used to combat osteomyelitis, as well as anti-inflammatory drugs and bisphosphonates, but delivery of growth factors is not covered in this review. In each case reviewed, special attention has been given to the technology used for controlling the release of the loaded drugs. The possibility of designing multifunctional three-dimensional bone TE scaffolds for the emerging field of bone TE therapeutics is discussed. A detailed summary of drugs included in three-dimensional scaffolds and the several approaches developed to combine bioceramics with various polymeric biomaterials in composites for drug-delivery systems is included. The main results presented in the literature are discussed and the remaining challenges in the field are summarized with suggestions for future research directions. PMID:19864265

  11. Integrated three-dimensional optical MEMS for chip-based fluorescence detection

    NASA Astrophysics Data System (ADS)

    Hung, Kuo-Yung; Tseng, Fan-Gang; Khoo, Hwa-Seng

    2009-04-01

    This paper presents a novel fluorescence sensing chip for parallel protein microarray detection in the context of a 3-in-1 protein chip system. This portable microchip consists of a monolithic integration of CMOS-based avalanche photo diodes (APDs) combined with a polymer micro-lens, a set of three-dimensional (3D) inclined mirrors for separating adjacent light signals and a low-noise transformer-free dc-dc boost mini-circuit to power the APDs (ripple below 1.28 mV, 0-5 V input, 142 V and 12 mA output). We fabricated our APDs using the planar CMOS process so as to facilitate the post-CMOS integration of optical MEMS components such as the lenses. The APD arrays were arranged in unique circular patterns appropriate for detecting the specific fluorescently labelled protein spots in our study. The array-type APDs were designed so as to compensate for any alignment error as detected by a positional error signal algorithm. The condenser lens was used as a structure for light collection to enhance the fluorescent signals by about 25%. This element also helped to reduce the light loss due to surface absorption. We fabricated an inclined mirror to separate two adjacent fluorescent signals from different specimens. Excitation using evanescent waves helped reduce the interference of the excitation light source. This approach also reduced the number of required optical lenses and minimized the complexity of the structural design. We achieved detection floors for anti-rabbit IgG and Cy5 fluorescent dye as low as 0.5 ng/µl (~3.268 nM). We argue that the intrinsic nature of point-to-point and batch-detection methods as showcased in our chip offers advantages over the serial-scanning approach used in traditional scanner systems. In addition, our system is low cost and lightweight.

  12. Three-dimensional optic axis determination using variable-incidence-angle polarization-optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ugryumova, Nadezhda; Gangnus, Sergei V.; Matcher, Stephen J.

    2006-08-01

    Polarization optical coherence tomography (PSOCT) is a powerful technique to nondestructively map the retardance and fast-axis orientation of birefringent biological tissues. Previous studies have concentrated on the case where the optic axis lies on the plane of the surface. We describe a method to determine the polar angle of the optic axis of a uniaxial birefringent tissue by making PSOCT measurements with a number of incident illumination directions. The method is validated on equine flexor tendon, yielding a variability of 4% for the true birefringence and 3% for the polar angle. We use the method to map the polar angle of fibers in the transitional region of equine cartilage.

  13. Three-dimensional MEMS optical switch for fiber optic communication applications

    NASA Astrophysics Data System (ADS)

    Nguyen, Khanh C.

    2002-09-01

    Micro-electromechanical Systems (MEMS) have been around since the 1960s. Early applications of MEMS were biomedical and automotive such as drug delivery system, disposable blood pressure sensors, accelerometer used in airbag sensor and antilock braking systems. Recently, this technology, known as micro-optical MEMS or MOEMS, is invading the fiber optic communication industry for its ability of moving and managing light directly without converting the optical data to electrical signal for processing, hence it is immune to bit rate and data protocol. This paper will discuss the 3D MEMS optical switch development program at Agere Systems from the design concept to volume production and the dedicated reliability program to qualify this technology for telecom applications.

  14. Three-dimensional surface microfluidics enabled by spatiotemporal control of elastic fluidic interface.

    PubMed

    Hong, Lingfei; Pan, Tingrui

    2010-12-07

    As an emerging alternative to the conventional counterpart, surface microfluidics incorporates both intrinsic resistive solid-liquid and elastic frictionless gas-liquid interfaces, leading to unique flow-pressure characteristics. Furthermore, the open-surface microfluidic platforms can be fabricated on a monolithic substrate with high wettability contrast by the previously reported one-step lithographic process of a photosensitive superhydrophobic nanocomposite material, which permits flexible fluidic operations and direct surface modifications. In the paper, we first present three-dimensional microfluidic manipulations utilizing the unconventional gas-liquid interfaces of surface microfluidics, outlined by the micropatterned wetting boundaries (also known as the triple lines). In contrast to the primary linear (resistive) nature of the conventional closed-channel microfluidics, the distinct elastic interface of surface microfluidics enables remarkable three-dimensional (deformable) and time-dependent (capacitive) operations of the flow. Specifically, spatiotemporal dependence of microflow patterns on the planar fluidic surfaces has been theoretically analyzed and experimentally characterized. Utilizing the unconventional interface-enabled flow-pressure relationship, novel surface fluidic operations, including microflow regulation and flow-controlled switching, have been demonstrated and fully investigated. Furthermore, three-dimensional surface microfluidic networks together with analog-to-digital stereo-flow activations have been established, in which miniature capillary bridges form fluidic connections between two independent surface microfluidic circuits.

  15. Bottle beam based optical trapping system for three-dimensional trapping of high and low index microparticles

    NASA Astrophysics Data System (ADS)

    Ahluwalia, Balpreet Singh; Yuan, Xiaocong; Tao, Shaohua

    2005-08-01

    The quest for applying optical tweezers system for novel applications has aggrandized its trapping capabilities since its inception. Researchers have proposed and applied light based micro-manipulation technique in the field of colloidal sciences, bioscience, MEMS and the count is limitless. In this paper we report the self-imaged optical bottle beam based optical tweezers system. A self-imaged bottle beam possesses three-dimensional intensity-null points along the propagation axis. The transverse intensity profile of the self-imaged bottle beam oscillates along the propagation axis, hence providing three-dimensional trapping potential for high and low indices microparticles at constructive and destructive interference points, respectively. Bottle beam based optical tweezer system adds the beneficial property of Gaussian and Bessel beam based trapping systems by providing three-dimensional trapping potential and self-reconstruction ability, respectively. As self-imaged bottle beam belong to the family of propagation-invariant beams, it can be used to trap chain of high and low indices microparticles three-dimensionally along the propagation directions, which can be used to periodically stack microparticles (of different refractive index) longitudinally.

  16. 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.

  17. 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.

  18. Tactical traffic control for multiple AGV systems based on three dimensional space

    NASA Astrophysics Data System (ADS)

    Noh, Yuna; Yoon, Yoonjin

    2016-12-01

    In dynamic environment, it is required to frequently alter pre-defined path for individual AGV. A two-staged traffic control scheme for multiple AGVs is highly efficient in complex environment. The initial path table is generated from the first scheme by path following of `cost map'. The second scheme is tactical conflict resolution and the traffic controller identifies conflicts by performing the cell overlapping test. Three dimensional map, countable state space which is equally-spaced cells with discrete time domain, makes the algorithm apt for identifying conflicts. Finally, the efficiency of the proposed algorithm is examined and compared with Breadth-first search algorithm.

  19. Three-Dimensional Radiologic Study on Index Measurement of Endonasal Endoscopic Optic Nerve Decompression.

    PubMed

    Zhao, Yao; Duan, Haobo; Liu, Jianming; Cheng, Kailiang; Han, Yingying; Li, Youqiong

    2017-09-01

    To provide the radiologic basis for the clinical application of endonasal endoscopic optic nerve decompression (EEOND). CTA images were used to observe the optic canal (OC) and related structures of 60 patients (120 sides) with normal nasal, paranasal sinuses, OC, and other related structures. Optic canal could be classified as: the canal (10 sides, 8.33%), the semicanal (25 sides, 20.83%), the impression (49 sides, 40.83%), and the nonimpression (36 sides, 30%). According to its relationships with the sinuses, OC could be further typed as: ethmoid sinus (22 sides, 18.3%), sphenoid sinus (38 sides, 31.7%), ethmoid and sphenoid sinus (60 sides, 50%). The thickness of OC medial wall is about 1.11 ± 0.24 mm at orbital mouth, 0.87 ± 0.25 mm at middle part and 1.19 ± 0.27 mm at cranial mouth. The arc length of OC bone wall which can be opened from the sinus cavity is about 7.18 ± 0.76 mm at orbital mouth, 8.27 ± 0.93 mm at middle part, and 6.98 ± 0.89 mm at cranial mouth. The length of the OC medial wall is 12.18 ± 1.35 mm. In the three-dimensional Cartesian coordinate system that origined with the last point of middle turbinate root and oriented by temporal side, front side, and superior side, the coordinates of midpoints of OC medial wall are: (3.64 ± 1.11, 8.48 ± 1.65, 23.14 ± 2.67) at orbital mouth, (0.16 ± 1.21, 3.99 ± 1.80, 24.85 ± 2.67) at middle part, and (-3.59 ± 1.22, 0.77 ± 2.13, 26.39 ± 2.68) at cranial mouth. One length unit on the axes is a millimeter. Computed tomography (CT) scanning technique can measure the data of the OC in EEOND. It has great guiding significance for clinical operation.

  20. Three-dimensional dosimetry of small megavoltage radiation fields using radiochromic gels and optical CT scanning.

    PubMed

    Babic, Steven; McNiven, Andrea; Battista, Jerry; Jordan, Kevin

    2009-04-21

    The dosimetry of small fields as used in stereotactic radiotherapy, radiosurgery and intensity-modulated radiation therapy can be challenging and inaccurate due to partial volume averaging effects and possible disruption of charged particle equilibrium. Consequently, there exists a need for an integrating, tissue equivalent dosimeter with high spatial resolution to avoid perturbing the radiation beam and artificially broadening the measured beam penumbra. In this work, radiochromic ferrous xylenol-orange (FX) and leuco crystal violet (LCV) micelle gels were used to measure relative dose factors (RDFs), percent depth dose profiles and relative lateral beam profiles of 6 MV x-ray pencil beams of diameter 28.1, 9.8 and 4.9 mm. The pencil beams were produced via stereotactic collimators mounted on a Varian 2100 EX linear accelerator. The gels were read using optical computed tomography (CT). Data sets were compared quantitatively with dosimetric measurements made with radiographic (Kodak EDR2) and radiochromic (GAFChromic EBT) film, respectively. Using a fast cone-beam optical CT scanner (Vista), corrections for diffusion in the FX gel data yielded RDFs that were comparable to those obtained by minimally diffusing LCV gels. Considering EBT film-measured RDF data as reference, cone-beam CT-scanned LCV gel data, corrected for scattered stray light, were found to be in agreement within 0.5% and -0.6% for the 9.8 and 4.9 mm diameter fields, respectively. The validity of the scattered stray light correction was confirmed by general agreement with RDF data obtained from the same LCV gel read out with a laser CT scanner that is less prone to the acceptance of scattered stray light. Percent depth dose profiles and lateral beam profiles were found to agree within experimental error for the FX gel (corrected for diffusion), LCV gel (corrected for scattered stray light), and EBT and EDR2 films. The results from this study reveal that a three-dimensional dosimetry method utilizing

  1. IBSIMU: a three-dimensional simulation software for charged particle optics.

    PubMed

    Kalvas, T; Tarvainen, O; Ropponen, T; Steczkiewicz, O; Arje, J; Clark, H

    2010-02-01

    A general-purpose three-dimensional (3D) simulation code IBSIMU for charged particle optics with space charge is under development at JYFL. The code was originally developed for designing a slit-beam plasma extraction and nanosecond scale chopping for pulsed neutron generator, but has been developed further and has been used for many applications. The code features a nonlinear FDM Poisson's equation solver based on fast stabilized biconjugate gradient method with ILU0 preconditioner for solving electrostatic fields. A generally accepted nonlinear plasma model is used for plasma extraction. Magnetic fields can be imported to the simulations from other programs. The particle trajectories are solved using adaptive Runge-Kutta method. Steady-state and time-dependent problems can be modeled in cylindrical coordinates, two-dimensional (slit) geometry, or full 3D. The code is used via C++ programming language for versatility but it features an interactive easy-to-use postprocessing tool for diagnosing fields and particle trajectories. The open source distribution and public documentation make the code well suited for scientific use. IBSIMU has been used for modeling the 14 GHz ECR ion source extraction and for designing a four-electrode extraction for a 2.45 GHz microwave ion source at Jyväskylä. A grid extraction has also been designed for producing large uniform beam for creating conditions similar to solar wind. The code has also been used to design a H(-) extraction with electron dumping for the Cyclotron Institute of Texas A&M University.

  2. Automatic three-dimensional registration of intravascular optical coherence tomography images

    NASA Astrophysics Data System (ADS)

    Ughi, Giovanni J.; Adriaenssens, Tom; Larsson, Matilda; Dubois, Christophe; Sinnaeve, Peter R.; Coosemans, Mark; Desmet, Walter; D'hooge, Jan

    2012-02-01

    Intravascular optical coherence tomography (IV-OCT) is a catheter-based high-resolution imaging technique able to visualize the inner wall of the coronary arteries and implanted devices in vivo with an axial resolution below 20 μm. IV-OCT is being used in several clinical trials aiming to quantify the vessel response to stent implantation over time. However, stent analysis is currently performed manually and corresponding images taken at different time points are matched through a very labor-intensive and subjective procedure. We present an automated method for the spatial registration of IV-OCT datasets. Stent struts are segmented through consecutive images and three-dimensional models of the stents are created for both datasets to be registered. The two models are initially roughly registered through an automatic initialization procedure and an iterative closest point algorithm is subsequently applied for a more precise registration. To correct for nonuniform rotational distortions (NURDs) and other potential acquisition artifacts, the registration is consecutively refined on a local level. The algorithm was first validated by using an in vitro experimental setup based on a polyvinyl-alcohol gel tubular phantom. Subsequently, an in vivo validation was obtained by exploiting stable vessel landmarks. The mean registration error in vitro was quantified to be 0.14 mm in the longitudinal axis and 7.3-deg mean rotation error. In vivo validation resulted in 0.23 mm in the longitudinal axis and 10.1-deg rotation error. These results indicate that the proposed methodology can be used for automatic registration of in vivo IV-OCT datasets. Such a tool will be indispensable for larger studies on vessel healing pathophysiology and reaction to stent implantation. As such, it will be valuable in testing the performance of new generations of intracoronary devices and new therapeutic drugs.

  3. Automated volumetric stent analysis of in-vivo intracoronary optical coherence tomography three-dimensional datasets

    NASA Astrophysics Data System (ADS)

    Ughi, Giovanni J.; Adriaenssens, Tom; Onsea, Kevin; Dubois, Christophe; Coosemans, Mark; Sinnaeve, Peter; Desmet, Walter; D'hooge, Jan

    2011-06-01

    Intra-vascular Optical Coherence Tomography (IV-OCT) is an appropriate imaging modality for the evaluation of stent struts apposition and coverage in the coronary arteries. Most often, image analysis is performed by a time-consuming manual contour tracing process. Recently, we proposed an algorithm for fully automated lumen morphology and individual stent struts apposition/coverage quantification. In this manuscript further developments allowing for automatic segmentation of the stent contour are presented. As such, quantification of in-stent area, malapposition cross-sectional area (i.e. the area representing the space from the stent surface to the vessel wall) and coverage cross-sectional area (i.e. the area of the tissue covering the stent surface) are automatically obtained. Volumetric measurements of malapposition and coverage are then achieved through the analysis of equally-spaced consecutive IV-OCT cross-sectional images. In addition, uncovered and malapposed struts are automatically clustered through consecutive slices according to their three-dimensional spatial position. Finally, properties of each cluster (e.g. malapposition/coverage volumes and struts spatial location and distribution) are quantified allowing for a volumetric analysis of the implanted device. Validation of the algorithm was obtained taking as a reference manual measurements performed by an expert cardiologist. 102 in-vivo images, taken at random from 8 different patients, were both automatically and manually analyzed quantifying lumen and stent area. High Pearson's correlation coefficients (Rarea = 0.99) and Bland-Altman statistics, showing no significant bias and good limits of agreement, proved that the presented algorithm provides a robust and fast tool to automatically estimate apposition and coverage of stent through an entire in-vivo IV-OCT pullback. Such a tool will be important for the integration of this technology in clinical routine and large clinical trials.

  4. Three-Dimensional Spectral-Domain Optical Coherence Tomography Data Analysis for Glaucoma Detection

    PubMed Central

    Wollstein, Gadi; Bilonick, Richard A.; Folio, Lindsey S.; Nadler, Zach; Kagemann, Larry; Schuman, Joel S.

    2013-01-01

    Purpose To develop a new three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) data analysis method using a machine learning technique based on variable-size super pixel segmentation that efficiently utilizes full 3D dataset to improve the discrimination between early glaucomatous and healthy eyes. Methods 192 eyes of 96 subjects (44 healthy, 59 glaucoma suspect and 89 glaucomatous eyes) were scanned with SD-OCT. Each SD-OCT cube dataset was first converted into 2D feature map based on retinal nerve fiber layer (RNFL) segmentation and then divided into various number of super pixels. Unlike the conventional super pixel having a fixed number of points, this newly developed variable-size super pixel is defined as a cluster of homogeneous adjacent pixels with variable size, shape and number. Features of super pixel map were extracted and used as inputs to machine classifier (LogitBoost adaptive boosting) to automatically identify diseased eyes. For discriminating performance assessment, area under the curve (AUC) of the receiver operating characteristics of the machine classifier outputs were compared with the conventional circumpapillary RNFL (cpRNFL) thickness measurements. Results The super pixel analysis showed statistically significantly higher AUC than the cpRNFL (0.855 vs. 0.707, respectively, p = 0.031, Jackknife test) when glaucoma suspects were discriminated from healthy, while no significant difference was found when confirmed glaucoma eyes were discriminated from healthy eyes. Conclusions A novel 3D OCT analysis technique performed at least as well as the cpRNFL in glaucoma discrimination and even better at glaucoma suspect discrimination. This new method has the potential to improve early detection of glaucomatous damage. PMID:23408988

  5. Practical fully three-dimensional reconstruction algorithms for diffuse optical tomography.

    PubMed

    Biswas, Samir Kumar; Kanhirodan, Rajan; Vasu, Ram Mohan; Roy, Debasish

    2012-06-01

    We have developed an efficient fully three-dimensional (3D) reconstruction algorithm for diffuse optical tomography (DOT). The 3D DOT, a severely ill-posed problem, is tackled through a pseudodynamic (PD) approach wherein an ordinary differential equation representing the evolution of the solution on pseudotime is integrated that bypasses an explicit inversion of the associated, ill-conditioned system matrix. One of the most computationally expensive parts of the iterative DOT algorithm, the reevaluation of the Jacobian in each of the iterations, is avoided by using the adjoint-Broyden update formula to provide low rank updates to the Jacobian. In addition, wherever feasible, we have also made the algorithm efficient by integrating along the quadratic path provided by the perturbation equation containing the Hessian. These algorithms are then proven by reconstruction, using simulated and experimental data and verifying the PD results with those from the popular Gauss-Newton scheme. The major findings of this work are as follows: (i) the PD reconstructions are comparatively artifact free, providing superior absorption coefficient maps in terms of quantitative accuracy and contrast recovery; (ii) the scaling of computation time with the dimension of the measurement set is much less steep with the Jacobian update formula in place than without it; and (iii) an increase in the data dimension, even though it renders the reconstruction problem less ill conditioned and thus provides relatively artifact-free reconstructions, does not necessarily provide better contrast property recovery. For the latter, one should also take care to uniformly distribute the measurement points, avoiding regions close to the source so that the relative strength of the derivatives for measurements away from the source does not become insignificant.

  6. High resolution three-dimensional reconstruction of the collagenous matrix of the human optic nerve head.

    PubMed

    Winkler, Moritz; Jester, Bryan; Nien-Shy, Chyong; Massei, Salina; Minckler, Don S; Jester, James V; Brown, Donald J

    2010-02-15

    Glaucoma is the second most common cause of blindness worldwide, leading to irreversible loss of vision. Prior studies indicate that ocular pressure-induced displacement of the lamina cribrosa (LC) may be responsible for retinal ganglion cell axon damage inside the neural canal. We present a novel approach to imaging the entire lamina cribrosa and the scleral canal at high lateral and axial resolution by using a combination of array tomography and nonlinear optical imaging of serial ultrathin orthogonal sections to detect second harmonic generated (SHG) signals from collagen. The resulting images can be analyzed individually or combined to form a three-dimensional reconstruction of the lamina. Due to the specificity of SHG generated from collagen the density and distribution of collagen inside the scleral canal can be objectively quantified with a high degree of accuracy. The reconstruction shows a non-uniform distribution of collagen along both the longitudinal and orthogonal axes. Mapping the collagen density by geographic region reveals significant differences in collagen content that result in "thin spots" with low collagen density as well as areas of very high collagen content. This suggests a non-uniform mechanical stiffness across the lamina that may account for increased axon damage observed in glaucoma patients. The inferior temporal region of the ONH in particular is marked by low collagen density, which corresponds with clinical observations identifying this region as being more susceptible to damage during the onset of glaucoma. Further application of this technique will help characterize the relationship of age, race and gender on the morphology of the LC.

  7. Two-step design method for highly compact three-dimensional freeform optical system for LED surface light source.

    PubMed

    Mao, Xianglong; Li, Hongtao; Han, Yanjun; Luo, Yi

    2014-10-20

    Designing an illumination system for a surface light source with a strict compactness requirement is quite challenging, especially for the general three-dimensional (3D) case. In accordance with the two key features of an expected illumination distribution, i.e., a well-controlled boundary and a precise illumination pattern, a two-step design method is proposed in this paper for highly compact 3D freeform illumination systems. In the first step, a target shape scaling strategy is combined with an iterative feedback modification algorithm to generate an optimized freeform optical system with a well-controlled boundary of the target distribution. In the second step, a set of selected radii of the system obtained in the first step are optimized to further improve the illuminating quality within the target region. The method is quite flexible and effective to design highly compact optical systems with almost no restriction on the shape of the desired target field. As examples, three highly compact freeform lenses with ratio of center height h of the lens and the maximum dimension D of the source ≤ 2.5:1 are designed for LED surface light sources to form a uniform illumination distribution on a rectangular, a cross-shaped and a complex cross pierced target plane respectively. High light control efficiency of η > 0.7 as well as low relative standard illumination deviation of RSD < 0.07 is obtained simultaneously for all the three design examples.

  8. Vortical Solitons of Three-Dimensional Bose—Einstein Condensates under Both a Bichromatic Optical Lattice and Anharmonic Potentials

    NASA Astrophysics Data System (ADS)

    Li, Feng-Bo; Zong, Feng-De; Wang, Ying

    2013-06-01

    We study Bose—Einstein condensate vortical solitons under both a bichromatic optical lattice and anharmonic potential. The vortical solitons are built in the form of a layer-chain structure made up of two fundamental vortices along the bichromatic optical lattice direction, which have not been reported before in the three-dimensional Bose—Einstein condensate. A variation approach is applied to find the optimum initial solutions of vortical solitons. The stabilities of the vortical solitons are confirmed by the numerical simulation of the time-dependent Gross—Pitaevskii equation. In particular, stable Bose—Einstein condensate vortical solitons with fundamental vortices of different atomic numbers in the external potential within a range of experimentally achievable timescales are found. We further manipulate the vortical solitons to an arbitrary position by steadily moving the bichromatic optical lattice, and find a stable region for the successful manipulation of vortical solitons without collapse. These results provide insight into controlling and manipulating the Bose—Einstein condensate vortical solitons for macroscopic quantum applications.

  9. Optical phase cloaking of 700 nm light waves in the far field by a three-dimensional carpet cloak.

    PubMed

    Ergin, Tolga; Fischer, Joachim; Wegener, Martin

    2011-10-21

    Transformation optics is a design tool that connects the geometry of space and propagation of light. Invisibility cloaking is a corresponding benchmark example. Recent experiments at optical frequencies have demonstrated cloaking for the light amplitude only. In this Letter, we demonstrate far-field cloaking of the light phase by interferometric microscope-imaging experiments on the previously introduced three-dimensional carpet cloak at 700 nm wavelength and for arbitrary polarization of light. © 2011 American Physical Society

  10. Integrated multifunctional reprogrammable MEMS deformable mirror and three-dimensional phase retrieval based adaptive optic system implementations

    NASA Astrophysics Data System (ADS)

    Rogers, Stanley

    This research presents a fast three-dimensional phase retrieval approach used to perform optical phase modulation through the use of a segmented Micro-Electro-Mechanical Deformable-Mirror (MEMS-DM). This research demonstrates novel adaptive optic system laser-beam implementations, for beam splitting, beam steering, beam shaping, beam tracking, and aberration correction, using an inherently multifunctional phased array system. Traditional solutions to beam splitting, beam steering, beam shaping (BS3), and beam tracking and aberration correction involve multiple and sometimes costly optical components. For example, beam splitting is normally accomplished with beam splitters, beam steering is normally achieved with gimbaled mechanical devices, and beam shaping is normally done with addressable, polarized, and potentially absorptive devices such as LCDs. In addition, beam tracking and aberration correction techniques require closed loop feedback, which is provided by the closed-loop three-dimensional phase retrieval algorithm implemented in this research. Using the 3D phase retrieval algorithm with a desired far-field amplitude pattern as a constraint, a segmented wavefront control device is shown to simultaneously perform the aforementioned functions through its inherent reconfigurable operation. The MEMS-DM used is a foundry micro-fabricated device that is attractive for optical phase modulation applications primarily because of its inherent low cost and low driving voltages. The MEMS-DM provides the added advantage of "discrete imaging" versus "continuously moving" imaging systems presented by current technology. The MEMS-DM shapes the beam based on the results of a modified Fienup and Roggemann/Lee phase retrieval algorithm implemented within the system. The optical bench setup and the experimental results for BS3 and beam tracking and aberration correction are presented. Simulations have been developed and presented to represent the optical system and the phase

  11. Detection of chlorobenzene in water using a wettability-controlled three-dimensional graphene selective filter

    NASA Astrophysics Data System (ADS)

    Lim, Taekyung; Lee, Jaejun; Kim, Jihyoung; Seo, Sungwon; Ju, Sanghyun

    2017-01-01

    An oxide nanowire transistor covered with a wettability-controlled three-dimensional (3D) graphene filter was fabricated to detect chlorobenzene in water. The 3D porous graphene filter allowed chlorobenzene to pass through while blocking water because of its wettability. The chlorobenzene concentration in water could be monitored by observing the threshold voltage shift, which moved to the negative direction with increasing chlorobenzene concentration in water. The advantage of the fabricated device is that it can be used to easily estimate the chlorobenzene concentration in water by consistently monitoring current.

  12. Vertical stacking of three-dimensional nanostructures via an aerosol lithography for advanced optical applications.

    PubMed

    Lee, Kiwoong; Choi, Hoseop; Kim, Dae Seong; Jang, Min Seok; Choi, Mansoo

    2017-09-29

    In this report, we introduce a method utilizing ion-assisted aerosol lithography (IAAL) to stack 3D nanostructures vertically. The stacked 3D nanostructures exhibit extraordinary optical properties: the double layer 3D nanostructures show more than 5-fold increased surface enhanced Raman scattering (SERS) intensities compared to their single layer counterpart. This unusual enhancement of Raman intensity implies the existence of additional vertical hotspots formed by interlayer cavity effects between the lower and upper nanostructures. Allowing for full 3-dimensional control in nanofabrication, this work provides a reliable way to create complex-shaped advanced optical nanostructures with non-intuitive bulk optical properties. © 2017 IOP Publishing Ltd.

  13. Global tracking control of underactuated ODINs in three-dimensional space

    NASA Astrophysics Data System (ADS)

    Do, K. D.

    2013-02-01

    This article presents a method to design controllers that force an underactuated omni-directional intelligent navigator (ODIN), a spherical underwater vehicle, to track a reference trajectory in three-dimensional space. The vehicle under consideration has only four thrusters but six degrees of freedom to be controlled. Motivated by the vehicle's steering practice, the roll and pitch angles regarded as virtual controls plus four actual control forces provided by the thrusters are used to force the position and yaw angle of the vehicle to globally and asymptotically track their reference trajectories. The control design is based on the one-step ahead backstepping method and Lyapunov's direct method. A combination of Euler angles and unit-quaternion for the attitude representation of the vehicle is used to obtain global tracking control results. Simulations illustrate the results.

  14. System Performance Analysis of Three Dimensional Reaction Wheel for the Attitude Control of Microsatellites

    NASA Astrophysics Data System (ADS)

    Shirasawa, Yoji; Tsuda, Yuichi

    This paper presents a novel attitude control device which is called three dimensional reaction wheel (3DRW). 3DRW consists of only one levitated spherical mass which can rotate around arbitrary axes. This leads to the reduction of the weight and volume of the device as compared to existing reaction wheel. Furthermore, this device has no mechanical contact between rotor and stator, so the failure caused by the mechanical contact would be reduced. In this paper, the results of the analysis and experiment on the dynamics and control of 3DRW are shown. In the experiments of the rotation control, the air bearing system is used. Using this device, the characteristics of rotation of the spherical mass are obtained. To verify the feasibility of the concept of 3DRW, the experiments of angular velocity feedback control are carried out. The results of experiments are applied to the numerical simulation of the attitude control for microsatellites, and the feasibility of 3DRW is verified.

  15. Coordination control of quadrotor VTOL aircraft in three-dimensional space

    NASA Astrophysics Data System (ADS)

    Do, K. D.

    2015-03-01

    This paper presents a constructive design of distributed coordination controllers for a group of N quadrotor vertical take-off and landing (VTOL) aircraft in three-dimensional space. A combination of Euler angles and unit-quaternion for the attitude representation of the aircraft is used to result in an effective control design, and to reduce singularities in the aircraft's dynamics. The coordination control design is based on a new bounded control design technique for second-order systems and new pairwise collision avoidance functions. The pairwise collision functions are functions of both relative positions and relative velocities between the aircraft instead of only their relative positions as in the literature. To overcome the inherent underactuation of the aircraft, the roll and pitch angles of the aircraft are considered as immediate controls. Simulations illustrate the results.

  16. Three-dimensional patterning and morphological control of porous nanomaterials by gray-scale direct imprinting

    PubMed Central

    Ryckman, Judson D.; Jiao, Yang; Weiss, Sharon M.

    2013-01-01

    We present a method for direct three-dimensional (3D) patterning of porous nanomaterials through the application of a premastered and reusable gray-scale stamp. Four classes of 3D nanostructures are demonstrated for the first time in porous media: gradient profiles, digital patterns, curves and lens shapes, and sharp features including v-grooves, nano-pits, and ‘cookie-cutter’ particles. Further, we demonstrate this technique enables morphological tuning and direct tailoring of nanomaterial properties, including porosity, average pore size, dielectric constant, and plasmonic response. This work opens a rapid and low-cost route for fabricating novel nanostructures and devices utilizing porous nanomaterials, with promising applications spanning diffractive and plasmonic sensing, holography, micro- and transformation optics, and drug delivery and imaging. PMID:23518798

  17. Cuttlefish use visual cues to control three-dimensional skin papillae for camouflage.

    PubMed

    Allen, Justine J; Mäthger, Lydia M; Barbosa, Alexandra; Hanlon, Roger T

    2009-06-01

    Cephalopods (octopus, squid and cuttlefish) are known for their camouflage. Cuttlefish Sepia officinalis use chromatophores and light reflectors for color change, and papillae to change three-dimensional physical skin texture. Papillae vary in size, shape and coloration; nine distinct sets of papillae are described here. The objective was to determine whether cuttlefish use visual or tactile cues to control papillae expression. Cuttlefish were placed on natural substrates to evoke the three major camouflage body patterns: Uniform/Stipple, Mottle and Disruptive. Three versions of each substrate were presented: the actual substrate, the actual substrate covered with glass (removes tactile information) and a laminated photograph of the substrate (removes tactile and three-dimensional information because depth-of-field information is unavailable). No differences in Small dorsal papillae or Major lateral mantle papillae expression were observed among the three versions of each substrate. Thus, visual (not tactile) cues drive the expression of papillae in S. officinalis. Two sets of papillae (Major lateral mantle papillae and Major lateral eye papillae) showed irregular responses; their control requires future investigation. Finally, more Small dorsal papillae were shown in Uniform/Stipple and Mottle patterns than in Disruptive patterns, which may provide clues regarding the visual mechanisms of background matching versus disruptive coloration.

  18. Improvement of diffraction efficiency of three-dimensional magneto-optic spatial light modulator with magnetophotonic crystal

    SciTech Connect

    Nakamura, K.; Takagi, H. Lim, P. B.; Inoue, M.; Goto, Taichi; Horimai, H.; Yoshikawa, H.; Bove, V. M.

    2016-01-11

    We have developed three-dimensional magneto-optic spatial light modulators (3D-MOSLMs) that use magnetic domains as submicron scale pixels to represent holograms. Our display system uses a submicron-scale magnetic pixel array on an amorphous TbFe film to create a wide viewing angle hologram. However, in previous work the reconstructed images had a low intensity and a low optical contrast; brightness of the reconstructed image was 4.4 × 10{sup −2 }cd/m{sup 2} with 532 nm illumination light at 10.8 mW/cm{sup 2}, while display standard ISO13406 recommends 100 cd/m{sup 2} or more. In this paper, we describe our development of a 3D-MOSLM composed of an artificial magnetic lattice structure of magnetophotonic crystals (MPCs). The MPCs enhance the diffraction efficiency of reconstructed 3D images and reduce the power consumption for controlling the magnetic pixels by a light localization effect. We demonstrate reconstructed 3D images using the MPC and show significant brightness improvement.

  19. Three-dimensional structure and multistable optical switching of triple-twisted particle-like excitations in anisotropic fluids.

    PubMed

    Smalyukh, Ivan I; Lansac, Yves; Clark, Noel A; Trivedi, Rahul P

    2010-02-01

    Control of structures in soft materials with long-range order forms the basis for applications such as displays, liquid-crystal biosensors, tunable lenses, distributed feedback lasers, muscle-like actuators and beam-steering devices. Bistable, tristable and multistable switching of well-defined structures of molecular alignment is of special interest for all of these applications. Here we describe the facile optical creation and multistable switching of localized configurations in the molecular orientation field of a chiral nematic anisotropic fluid. These localized chiro-elastic particle-like excitations--dubbed 'triple-twist torons'--are generated by vortex laser beams and embed the localized three-dimensional (3D) twist into a uniform background. Confocal polarizing microscopy and computer simulations reveal their equilibrium internal structures, manifesting both skyrmion-like and Hopf fibration features. Robust generation of torons at predetermined locations combined with both optical and electrical reversible switching can lead to new ways of multistable structuring of complex photonic architectures in soft materials.

  20. Soft-Lithographical Fabrication of Three-dimensional Photonic Crystals in the Optical Regime

    SciTech Connect

    Lee, Jae-Hwang

    2006-01-01

    This dissertation describes several projects to realize low-cost and high-quality three-dimensional (3D) microfabrication using non-photolithographic techniques for layer-by-layer photonic crystals. Low-cost, efficient 3D microfabrication is a demanding technique not only for 3D photonic crystals but also for all other scientific areas, since it may create new functionalities beyond the limit of planar structures. However, a novel 3D microfabrication technique for photonic crystals implies the development of a complete set of sub-techniques for basic layer-by-layer stacking, inter-layer alignment, and material conversion. One of the conventional soft lithographic techniques, called microtransfer molding (μTM), was developed by the Whitesides group in 1996. Although μTM technique potentially has a number of advantages to overcome the limit of conventional photolithographic techniques in building up 3D microstructures, it has not been studied intensively after its demonstration. This is mainly because of technical challenges in the nature of layer-by-layer fabrication, such as the demand of very high yield in fabrication. After two years of study on conventional μTM, We have developed an advanced microtransfer molding technique, called two-polymer microtransfer molding (2P-μTM) that shows an extremely high yield in layer-by-layer microfabrication sufficient to produce highly layered microstructures. The use of two different photo-curable prepolymers, a filler and an adhesive, allows for fabrication of layered microstructures without thin films between layers. The capabilities of 2P-μTM are demonstrated by the fabrication of a wide-area 12-layer microstructure with high structural fidelity. Second, we also had to develop an alignment technique. We studied the 1st-order diffracted moire fringes of transparent multilayered structures comprised of irregularly deformed periodic patterns. By a comparison study of the diffracted moire fringe pattern and detailed

  1. FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): In-Situ Characterization of Three-Dimensional Optical Matters by Light Diffraction

    NASA Astrophysics Data System (ADS)

    Jiang, Lai-Dong; Dai, Qiao-Feng; Feng, Tian-Hua; Liu, Jin; Wu, Li-Jun; Lan, Sheng; Gopal V., A.; Trofimov A., V.

    2009-07-01

    Three-dimensional optical matters are created by combining the single beam optical trapping with the conventional Z-scan technique. Dynamic light diffraction is employed to evaluate the structure and quality of the optical matter formed at the optimum trapping power. The lattice constant of the optical matter is extracted based on the Bragg and Snell laws, showing that polystyrene spheres are nearly close-packed in the optical matter, confirmed by comparing the diffraction pattern of the optical matter with that of a colloidal photonic crystal fabricated by the self-assembled technique. The relatively broad diffraction peaks observed in the optical matter indicate that the density of disorders in it is higher than that in the photonic crystal. It is suggested that the optical matter possesses a random close-packed structure rather than a face centered cubic one.

  2. Lumped versus distributed thermoregulatory control: results from a three-dimensional dynamic model.

    PubMed

    Werner, J; Buse, M; Foegen, A

    1989-01-01

    In this study we use a three-dimensional model of the human thermal system, the spatial grid of which is 0.5 ... 1.0 cm. The model is based on well-known physical heat-transfer equations, and all parameters of the passive system have definite physical values. According to the number of substantially different areas and organs, 54 spatially different values are attributed to each physical parameter. Compatibility of simulation and experiment was achieved solely on the basis of physical considerations and physiological basic data. The equations were solved using a modification of the alternating direction implicit method. On the basis of this complex description of the passive system close to reality, various lumped and distributed parameter control equations were tested for control of metabolic heat production, blood flow and sweat production. The simplest control equations delivering results on closed-loop control compatible with experimental evidence were determined. It was concluded that it is essential to take into account the spatial distribution of heat production, blood flow and sweat production, and that at least for control of shivering, distributed controller gains different from the pattern of distribution of muscle tissue are required. For sweat production this is not so obvious, so that for simulation of sweating control after homogeneous heat load a lumped parameter control may be justified. Based on these conclusions three-dimensional temperature profiles for cold and heat load and the dynamics for changes of the environmental conditions were computed. In view of the exact simulation of the passive system and the compatibility with experimentally attainable variables there is good evidence that those values extrapolated by the simulation are adequately determined. The model may be used both for further analysis of the real thermoregulatory mechanisms and for special applications in environmental and clinical health care.

  3. Three-dimensional flow structures and vorticity control in fish-like swimming

    NASA Astrophysics Data System (ADS)

    Zhu, Q.; Wolfgang, M. J.; Yue, D. K. P.; Triantafyllou, M. S.

    2002-10-01

    We employ a three-dimensional, nonlinear inviscid numerical method, in conjunction with experimental data from live fish and from a fish-like robotic mechanism, to establish the three-dimensional features of the flow around a fish-like body swimming in a straight line, and to identify the principal mechanisms of vorticity control employed in fish-like swimming. The computations contain no structural model for the fish and hence no recoil correction. First, we show the near-body flow structure produced by the travelling-wave undulations of the bodies of a tuna and a giant danio. As revealed in cross-sectional planes, for tuna the flow contains dominant features resembling the flow around a two-dimensional oscillating plate over most of the length of the fish body. For the giant danio, on the other hand, a mixed longitudinal transverse structure appears along the hind part of the body. We also investigate the interaction of the body-generated vortices with the oscillating caudal fin and with tail-generated vorticity. Two distinct vorticity interaction modes are identified: the first mode results in high thrust and is generated by constructive pairing of body-generated vorticity with same-sign tail-generated vorticity, resulting in the formation of a strong thrust wake; the second corresponds to high propulsive efficiency and is generated by destructive pairing of body-generated vorticity with opposite-sign tail-generated vorticity, resulting in the formation of a weak thrust wake.

  4. Numerical study of three-dimensional separation and flow control at a wing/body junction

    NASA Technical Reports Server (NTRS)

    Ash, Robert L.; Lakshmanan, Balakrishnan

    1989-01-01

    The problem of three-dimensional separation and flow control at a wing/body junction has been investigated numerically using a three-dimensional Navier-Stokes code. The numerical code employs an algebraic grid generation technique for generating the grid for unmodified junction and an elliptic grid generation technique for filleted fin junction. The results for laminar flow past a blunt fin/flat plate junction demonstrate that after grid refinement, the computations agree with experiment and reveal a strong dependency of the number of vortices at the junction on Mach number and Reynolds number. The numerical results for pressure distribution, particle paths and limiting streamlines for turbulent flow past a swept fin show a decrease in the peak pressure and in the extent of the separated flow region compared to the laminar case. The results for a filleted juncture indicate that the streamline patterns lose much of their vortical character with proper filleting. Fillets with a radius of three and one-half times the fin leading edge diameter or two times the incoming boundary layer thickness, significantly weaken the usual necklace interaction vortex for the Mach number and Reynolds number considered in the present study.

  5. Controlled synthesis of hyper-branched inorganic nanocrystals withrich three-dimensional structures

    SciTech Connect

    Kanaras, Antonios G.; Sonnichsen, Carsten; Liu, Haitao; Alivisatos, A. Paul

    2005-07-27

    Studies of crystal growth kinetics are tightly integrated with advances in the creation of new nanoscale inorganic building blocks and their functional assemblies 1-11. Recent examples include the development of semiconductor nanorods which have potential uses in solar cells 12-17, and the discovery of a light driven process to create noble metal particles with sharp corners that can be used in plasmonics 18,19. In the course of studying basic crystal growth kinetics we developed a process for preparing branched semiconductor nanocrystals such as tetrapods and inorganic dendrimers of precisely controlled generation 20,21. Here we report the discovery of a crystal growth kinetics regime in which a new class of hyper-branched nanocrystals are formed. The shapes range from 'thorny balls', to tree-like ramified structures, to delicate 'spider net'-like particles. These intricate shapes depend crucially on a delicate balance of branching and extension. The multitudes of resulting shapes recall the diverse shapes of snowflakes 22.The three dimensional nature of the branch points here, however, lead to even more complex arrangements than the two dimensionally branched structures observed in ice. These hyper-branched particles not only extend the available three-dimensional shapes in nanoparticle synthesis ,but also provide a tool to study growth kinetics by carefully observing and modeling particle morphology.

  6. Statistics Analysis of the Uncertainties in Cloud Optical Depth Retrievals Caused by Three-Dimensional Radiative Effects

    NASA Technical Reports Server (NTRS)

    Varnai, Tamas; Marshak, Alexander

    2000-01-01

    This paper presents a simple approach to estimate the uncertainties that arise in satellite retrievals of cloud optical depth when the retrievals use one-dimensional radiative transfer theory for heterogeneous clouds that have variations in all three dimensions. For the first time, preliminary error bounds are set to estimate the uncertainty of cloud optical depth retrievals. These estimates can help us better understand the nature of uncertainties that three-dimensional effects can introduce into retrievals of this important product of the MODIS instrument. The probability distribution of resulting retrieval errors is examined through theoretical simulations of shortwave cloud reflection for a wide variety of cloud fields. The results are used to illustrate how retrieval uncertainties change with observable and known parameters, such as solar elevation or cloud brightness. Furthermore, the results indicate that a tendency observed in an earlier study, clouds appearing thicker for oblique sun, is indeed caused by three-dimensional radiative effects.

  7. Three-dimensional speckle size in generalized optical systems with limiting apertures.

    PubMed

    Ward, Jennifer E; Kelly, Damien P; Sheridan, John T

    2009-08-01

    Correlation properties of speckle fields at the output of quadratic phase systems with hard square and circular apertures are examined. Using the linear canonical transform and ABCD ray matrix techniques to describe these general optical systems, we first derive analytical formulas for determining axial and lateral speckle sizes. Then using a numerical technique, we extend the analysis so that the correlation properties of nonaxial speckles can also be considered. Using some simple optical systems as examples, we demonstrate how this approach may be conveniently applied. The results of this analysis apply broadly both to the design of metrology systems and to speckle control schemes.

  8. Controlling bi-anisotropy in infrared metamaterials using three-dimensional split-ring-resonators for purely magnetic resonance.

    PubMed

    Moritake, Yuto; Tanaka, Takuo

    2017-07-27

    We propose and demonstrate the strategy to control bi-anisotropic response in three-dimensional split-ring-resonators (3D-SRRs) array for purely magnetic resonance in the mid-infrared region. By using a metal-stress-driven self-folding method, inversion symmetry along a propagation axis of 3D-SRRs was controlled. The inversion symmetry of 3D-SRRs realized non-bi-anisotropic response of a magnetic resonant mode at around 10 μm in wavelength resulting in purely magnetic resonance with high transmission of 70%. Highly transparent purely magnetic artificial elements demonstrated in this study will be a key component for functional applications using artificial magnetism at the optical frequencies.

  9. Development of an abbreviated-typed three-dimensional optical measuring apparatus for textile

    NASA Astrophysics Data System (ADS)

    Komatsubara, Ryohei

    2002-10-01

    This research evaluates the objectivity of textile goods by using the non-contact three dimensional measuring method. The object of the measurement is a seam and wrinkle of the shirt. The evaluation of textile goods was due to watching, and it was difficult to do an absolute evaluation. The existing three-dimensional measurement device is made to correspond to textile goods, and we convert into the series to which ruggedness information is decided by ISO and can output it. The measurement device uses the pattern projection method which introduces the phase shift, and can do high density measurement in a short time. Technical paper of ISO is made for this measurement device, and the work of standardization is proceeded.

  10. Depth-tunable three-dimensional display with interactive light field control

    NASA Astrophysics Data System (ADS)

    Xie, Songlin; Wang, Peng; Sang, Xinzhu; Li, Chenyu; Dou, Wenhua; Xiao, Liquan

    2016-07-01

    A software-defined depth-tunable three-dimensional (3D) display with interactive 3D depth control is presented. With the proposed post-processing system, the disparity of the multi-view media can be freely adjusted. Benefiting from a wealth of information inherently contains in dense multi-view images captured with parallel arrangement camera array, the 3D light field is built and the light field structure is controlled to adjust the disparity without additional acquired depth information since the light field structure itself contains depth information. A statistical analysis based on the least square is carried out to extract the depth information inherently exists in the light field structure and the accurate depth information can be used to re-parameterize light fields for the autostereoscopic display, and a smooth motion parallax can be guaranteed. Experimental results show that the system is convenient and effective to adjust the 3D scene performance in the 3D display.

  11. Controlling the crystalline three-dimensional order in bulk materials by single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    López-Andarias, Javier; López, Juan Luis; Atienza, Carmen; Brunetti, Fulvio G.; Romero-Nieto, Carlos; Guldi, Dirk M.; Martín, Nazario

    2014-04-01

    The construction of ordered single-wall carbon nanotube soft-materials at the nanoscale is currently an important challenge in science. Here we use single-wall carbon nanotubes as a tool to gain control over the crystalline ordering of three-dimensional bulk materials composed of suitably functionalized molecular building blocks. We prepare p-type nanofibres from tripeptide and pentapeptide-containing small molecules, which are covalently connected to both carboxylic and electron-donating 9,10-di(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene termini. Adding small amounts of single-wall carbon nanotubes to the so-prepared p-nanofibres together with the externally controlled self assembly by charge screening by means of Ca2+ results in new and stable single-wall carbon nanotube-based supramolecular gels featuring remarkably long-range internal order.

  12. High-resolution liquid patterns via three-dimensional droplet shape control

    NASA Astrophysics Data System (ADS)

    Raj, Rishi; Adera, Solomon; Enright, Ryan; Wang, Evelyn N.

    2014-09-01

    Understanding liquid dynamics on surfaces can provide insight into nature’s design and enable fine manipulation capability in biological, manufacturing, microfluidic and thermal management applications. Of particular interest is the ability to control the shape of the droplet contact area on the surface, which is typically circular on a smooth homogeneous surface. Here, we show the ability to tailor various droplet contact area shapes ranging from squares, rectangles, hexagons, octagons, to dodecagons via the design of the structure or chemical heterogeneity on the surface. We simultaneously obtain the necessary physical insights to develop a universal model for the three-dimensional droplet shape by characterizing the droplet side and top profiles. Furthermore, arrays of droplets with controlled shapes and high spatial resolution can be achieved using this approach. This liquid-based patterning strategy promises low-cost fabrication of integrated circuits, conductive patterns and bio-microarrays for high-density information storage and miniaturized biochips and biosensors, among others.

  13. UAV formation control design with obstacle avoidance in dynamic three-dimensional environment.

    PubMed

    Chang, Kai; Xia, Yuanqing; Huang, Kaoli

    2016-01-01

    This paper considers the artificial potential field method combined with rotational vectors for a general problem of multi-unmanned aerial vehicle (UAV) systems tracking a moving target in dynamic three-dimensional environment. An attractive potential field is generated between the leader and the target. It drives the leader to track the target based on the relative position of them. The other UAVs in the formation are controlled to follow the leader by the attractive control force. The repulsive force affects among the UAVs to avoid collisions and distribute the UAVs evenly on the spherical surface whose center is the leader-UAV. Specific orders or positions of the UAVs are not required. The trajectories of avoidance obstacle can be obtained through two kinds of potential field with rotation vectors. Every UAV can choose the optimal trajectory to avoid the obstacle and reconfigure the formation after passing the obstacle. Simulations study on UAV are presented to demonstrate the effectiveness of proposed method.

  14. Three-dimensional Optical Coherence Tomography for Optical Biopsy of Lymph Nodes and Assessment of Metastatic Disease

    PubMed Central

    John, Renu; Adie, Steven G.; Chaney, Eric J.; Marjanovic, Marina; Tangella, Krishnarao V.; Boppart, Stephen A.

    2013-01-01

    Background Numerous techniques have been developed for localizing lymph nodes before surgical resection and for their histological assessment. Nondestructive high-resolution transcapsule optical imaging of lymph nodes offers the potential for in situ assessment of metastatic involvement, potentially during surgical procedures. Methods Three-dimensional optical coherence tomography (3-D OCT) was used for imaging and assessing resected popliteal lymph nodes from a preclinical rat metastatic tumor model over a 9-day time-course study after tumor induction. The spectral-domain OCT system utilized a center wavelength of 800 nm, provided axial and transverse resolutions of 3 and 12 µm, respectively, and performed imaging at 10,000 axial scans per second. Results OCT is capable of providing high-resolution labelfree images of intact lymph node microstructure based on intrinsic optical scattering properties with penetration depths of ~1–2 mm. The results demonstrate that OCT is capable of differentiating normal, reactive, and metastatic lymph nodes based on microstructural changes. The optical scattering and structural changes revealed by OCT from day 3 to day 9 after the injection of tumor cells into the lymphatic system correlate with inflammatory and immunological changes observed in the capsule, precortical regions, follicles, and germination centers found during histopathology. Conclusions We report for the first time a longitudinal study of 3-D transcapsule OCT imaging of intact lymph nodes demonstrating microstructural changes during metastatic infiltration. These results demonstrate the potential of OCT as a technique for intraoperative, real-time in situ 3-D optical biopsy of lymph nodes for the intraoperative staging of cancer. PMID:22688663

  15. Formation of spatially and geometrically controlled three-dimensional tissues in soft gels by sacrificial micromolding.

    PubMed

    Cerchiari, Alec; Garbe, James C; Todhunter, Michael E; Jee, Noel Y; Pinney, James R; LaBarge, Mark A; Desai, Tejal A; Gartner, Zev J

    2015-06-01

    Patterned three-dimensional (3D) cell culture models aim to more accurately represent the in vivo architecture of a tissue for the purposes of testing drugs, studying multicellular biology, or engineering functional tissues. However, patterning 3D multicellular structures within very soft hydrogels (<500 Pa) that mimic the physicochemical environment of many tissues remains a challenge for existing methods. To overcome this challenge, we use a Sacrificial Micromolding technique to temporarily form spatially and geometrically defined 3D cell aggregates in degradable scaffolds before transferring and culturing them in a reconstituted extracellular matrix. Herein, we demonstrate that Sacrificial Micromolding (1) promotes cyst formation and proper polarization of established epithelial cell lines, (2) allows reconstitution of heterotypic cell-cell interactions in multicomponent epithelia, and (3) can be used to control the lumenization-state of epithelial cysts as a function of tissue size. In addition, we discuss the potential of Sacrificial Micromolding as a cell-patterning tool for future studies.

  16. Spin injection and helicity control of surface spin photocurrent in a three dimensional topological insulator.

    PubMed

    Huang, Y Q; Song, Y X; Wang, S M; Buyanova, I A; Chen, W M

    2017-05-22

    A three-dimensional (3D) topological insulator (TI) is a unique quantum phase of matter with exotic physical properties and promising spintronic applications. However, surface spin current in a common 3D TI remains difficult to control and the out-of-plane spin texture is largely unexplored. Here, by means of surface spin photocurrent in Bi2Te3 TI devices driven by circular polarized light, we identify the subtle effect of the spin texture of the topological surface state including the hexagonal warping term on the surface current. By exploring the out-of-plane spin texture, we demonstrate spin injection from GaAs to TI and its significant contribution to the surface current, which can be manipulated by an external magnetic field. These discoveries pave the way to not only intriguing new physics but also enriched spin functionalities by integrating TI with conventional semiconductors, such that spin-enabled optoelectronic devices may be fabricated in such hybrid structures.

  17. Spin injection and helicity control of surface spin photocurrent in a three dimensional topological insulator

    NASA Astrophysics Data System (ADS)

    Huang, Y. Q.; Song, Y. X.; Wang, S. M.; Buyanova, I. A.; Chen, W. M.

    2017-05-01

    A three-dimensional (3D) topological insulator (TI) is a unique quantum phase of matter with exotic physical properties and promising spintronic applications. However, surface spin current in a common 3D TI remains difficult to control and the out-of-plane spin texture is largely unexplored. Here, by means of surface spin photocurrent in Bi2Te3 TI devices driven by circular polarized light, we identify the subtle effect of the spin texture of the topological surface state including the hexagonal warping term on the surface current. By exploring the out-of-plane spin texture, we demonstrate spin injection from GaAs to TI and its significant contribution to the surface current, which can be manipulated by an external magnetic field. These discoveries pave the way to not only intriguing new physics but also enriched spin functionalities by integrating TI with conventional semiconductors, such that spin-enabled optoelectronic devices may be fabricated in such hybrid structures.

  18. Spatially controlled simultaneous patterning of multiple growth factors in three-dimensional hydrogels

    NASA Astrophysics Data System (ADS)

    Wylie, Ryan G.; Ahsan, Shoeb; Aizawa, Yukie; Maxwell, Karen L.; Morshead, Cindi M.; Shoichet, Molly S.

    2011-10-01

    Three-dimensional (3D) protein-patterned scaffolds provide a more biomimetic environment for cell culture than traditional two-dimensional surfaces, but simultaneous 3D protein patterning has proved difficult. We developed a method to spatially control the immobilization of different growth factors in distinct volumes in 3D hydrogels, and to specifically guide differentiation of stem/progenitor cells therein. Stem-cell differentiation factors sonic hedgehog (SHH) and ciliary neurotrophic factor (CNTF) were simultaneously immobilized using orthogonal physical binding pairs, barnase-barstar and streptavidin-biotin, respectively. Barnase and streptavidin were sequentially immobilized using two-photon chemistry for subsequent concurrent complexation with fusion proteins barstar-SHH and biotin-CNTF, resulting in bioactive 3D patterned hydrogels. The technique should be broadly applicable to the patterning of a wide range of proteins.

  19. Controlling microstructure of three-dimensional scaffolds from regenerated silk fibroin by adjusting pH.

    PubMed

    Cho, Se Youn; Heo, Semi; Jin, Hyoung-Joon

    2012-01-01

    For tissue engineering, it is very important to design and control the pore architecture of three-dimensional (3D) polymeric scaffolds, which plays an important role in directing tissue formation and function. In this study, 3D porous silk fibroin scaffolds produced using a freeze drying technique were prepared at pHs ranging from 5 to 9. The effects of pH on the pore microstructure of the silk fibroin scaffold were examined by rheometry, FESEM and FTIR. Different pore structures were formed according to the pH of silk fibroin because silk fibroin exhibits water-like behavior under basic conditions and gel-like behavior under acidic conditions.

  20. Differentiation of benign and malignant breast tumors by in-vivo three-dimensional parallel-plate diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Choe, Regine; Konecky, Soren D.; Corlu, Alper; Lee, Kijoon; Durduran, Turgut; Busch, David R.; Pathak, Saurav; Czerniecki, Brian J.; Tchou, Julia; Fraker, Douglas L.; Demichele, Angela; Chance, Britton; Arridge, Simon R.; Schweiger, Martin; Culver, Joseph P.; Schnall, Mitchell D.; Putt, Mary E.; Rosen, Mark A.; Yodh, Arjun G.

    2009-03-01

    We have developed a novel parallel-plate diffuse optical tomography (DOT) system for three-dimensional in vivo imaging of human breast tumor based on large optical data sets. Images of oxy-, deoxy-, and total hemoglobin concentration as well as blood oxygen saturation and tissue scattering were reconstructed. Tumor margins were derived using the optical data with guidance from radiology reports and magnetic resonance imaging. Tumor-to-normal ratios of these endogenous physiological parameters and an optical index were computed for 51 biopsy-proven lesions from 47 subjects. Malignant cancers (N=41) showed statistically significant higher total hemoglobin, oxy-hemoglobin concentration, and scattering compared to normal tissue. Furthermore, malignant lesions exhibited a twofold average increase in optical index. The influence of core biopsy on DOT results was also explored; the difference between the malignant group measured before core biopsy and the group measured more than 1 week after core biopsy was not significant. Benign tumors (N=10) did not exhibit statistical significance in the tumor-to-normal ratios of any parameter. Optical index and tumor-to-normal ratios of total hemoglobin, oxy-hemoglobin concentration, and scattering exhibited high area under the receiver operating characteristic curve values from 0.90 to 0.99, suggesting good discriminatory power. The data demonstrate that benign and malignant lesions can be distinguished by quantitative three-dimensional DOT.

  1. Three-dimensional correction of conduction velocity in the embryonic heart using integrated optical mapping and optical coherence tomography

    PubMed Central

    Ma, Pei; Wang, Yves T.; Gu, Shi; Watanabe, Michiko; Jenkins, Michael W.; Rollins, Andrew M.

    2014-01-01

    Abstract. Optical mapping (OM) of cardiac electrical activity conventionally collects information from a three-dimensional (3-D) surface as a two-dimensional (2-D) projection map. When applied to measurements of the embryonic heart, this method ignores the substantial and complex curvature of the heart surface, resulting in significant errors when calculating conduction velocity, an important electrophysiological parameter. Optical coherence tomography (OCT) is capable of imaging the 3-D structure of the embryonic heart and accurately characterizing the surface topology. We demonstrate an integrated OCT/OM imaging system capable of simultaneous conduction mapping and 3-D structural imaging. From these multimodal data, we obtained 3-D activation maps and corrected conduction velocity maps of early embryonic quail hearts. 3-D correction eliminates underestimation bias in 2-D conduction velocity measurements, therefore enabling more accurate measurements with less experimental variability. The integrated system will also open the door to correlate the structure and electrophysiology, thereby improving our understanding of heart development. PMID:24996663

  2. Integration of optical clearing and optical sectioning microscopy for three-dimensional imaging of natural biomaterial scaffolds in thin sections

    NASA Astrophysics Data System (ADS)

    Tseng, S.-Ja; Lee, Ying-Hui; Chen, Zhi-Hao; Lin, Hui-Hao; Lin, Chih-Yung; Tang, Shiue-Cheng

    2009-07-01

    The intrinsic turbidity of scaffolds formed by natural biomaterials such as collagen fibers prevents high-resolution light microscopy in depth. In this research, we have developed a new method of using light microscopy for penetrative three-dimensional (3-D) visualization of scaffolds formed by collagen, chitosan, or cellulose. First, we applied an optical-clearing solution, FocusClear, to permeate and reduce the turbidity of the scaffolds. The improved photon penetration allowed fluorophores for efficient excitation and emission in the FocusClear solution. Confocal microscopy was applied to achieve cellular-level resolution up to 350 μm for both the fibroblast/collagen and the osteoblast/chitosan constructs and micrometer-level resolution up to 40 μm for the cellulose membrane. The depth of imaging of the cellulose membrane was further improved to 80 μm using two-photon microscopy. Significantly, these voxel-based confocal/two-photon micrographs allowed postrecording image processing via Amira projection algorithms for 3-D visualization and analysis of the scanned region. Although this optical method remains limited in viewing block scaffolds in thin sections, our approach provides a noninvasive way to microscopically examine the scaffold structure, which would be a valuable tool to studying biomaterials and their interactions with the molecule/cell of interest within the scaffold in an integrated fashion.

  3. Surface Description and Motion Control for Animated Three Dimensional Computer Generated Characters.

    ERIC Educational Resources Information Center

    Hutchinson, Thomas Lloyd

    This study of the relationship of computer technology to character animation focuses on the advantages and constraints of developing three-dimensional characters for computer animation. Three different levels of the complexity involved in animating characters are examined: (1) a three-dimensional computer environment and simple motion within this…

  4. Surface Description and Motion Control for Animated Three Dimensional Computer Generated Characters.

    ERIC Educational Resources Information Center

    Hutchinson, Thomas Lloyd

    This study of the relationship of computer technology to character animation focuses on the advantages and constraints of developing three-dimensional characters for computer animation. Three different levels of the complexity involved in animating characters are examined: (1) a three-dimensional computer environment and simple motion within this…

  5. Longitudinal spin separation of light and its performance in three-dimensionally controllable spin-dependent focal shift

    PubMed Central

    Liu, Sheng; Li, Peng; Zhang, Yi; Gan, Xuetao; Wang, Meirong; Zhao, Jianlin

    2016-01-01

    Spin Hall effect of light, which is normally explored as a transverse spin-dependent separation of a light beam, has attracted enormous research interests. However, it seems there is no indication for the existence of the longitudinal spin separation of light. In this paper, we propose and experimentally realize the spin separation along the propagation direction by modulating the Pancharatnam-Berry (PB) phase. Due to the spin-dependent divergence and convergence determined by the PB phase, a focused Gaussian beam could split into two opposite spin states, and focuses at different distances, representing the longitudinal spin separation. By combining this longitudinal spin separation with the transverse one, we experimentally achieve the controllable spin-dependent focal shift in three dimensional space. This work provides new insight on steering the spin photons, and is expected to explore novel applications of optical trapping, manipulating, and micromachining with higher degree of freedom. PMID:26882995

  6. Longitudinal spin separation of light and its performance in three-dimensionally controllable spin-dependent focal shift

    NASA Astrophysics Data System (ADS)

    Liu, Sheng; Li, Peng; Zhang, Yi; Gan, Xuetao; Wang, Meirong; Zhao, Jianlin

    2016-02-01

    Spin Hall effect of light, which is normally explored as a transverse spin-dependent separation of a light beam, has attracted enormous research interests. However, it seems there is no indication for the existence of the longitudinal spin separation of light. In this paper, we propose and experimentally realize the spin separation along the propagation direction by modulating the Pancharatnam-Berry (PB) phase. Due to the spin-dependent divergence and convergence determined by the PB phase, a focused Gaussian beam could split into two opposite spin states, and focuses at different distances, representing the longitudinal spin separation. By combining this longitudinal spin separation with the transverse one, we experimentally achieve the controllable spin-dependent focal shift in three dimensional space. This work provides new insight on steering the spin photons, and is expected to explore novel applications of optical trapping, manipulating, and micromachining with higher degree of freedom.

  7. Three-dimensional surface profiling and optical characterization of liquid microlens using a Shack-Hartmann wave front sensor.

    PubMed

    Li, Chenhui; Hall, Gunnsteinn; Zeng, Xuefeng; Zhu, Difeng; Eliceiri, Kevin; Jiang, Hongrui

    2011-04-25

    We demonstrate three-dimensional (3D) surface profiling of the water-oil interface in a tunable liquid microlens using a Shack-Hartmann wave front sensor. The principles and the optical setup for achieving 3D surface measurements are presented and a hydrogel-actuated liquid lens was measured at different focal lengths. The 3D surface profiles are then used to study the optical properties of the liquid lens. Our method of 3D surface profiling could foster the improvement of liquid lens design and fabrication, including surface treatment and aberration reduction.

  8. A novel lithography process for 3D (three-dimensional) interconnect using an optical direct-writing exposure system

    NASA Astrophysics Data System (ADS)

    Azuma, T.; Sekiguchi, M.; Matsuo, M.; Kawasaki, A.; Hagiwara, K.; Matsui, H.; Kawamura, N.; Kishimoto, K.; Nakamura, A.; Washio, Y.

    2010-03-01

    A novel lithography process for 3D (Three-dimensional) interconnect was developed using an optical direct-writing exposure tool. A reflective IR (Infra-red) alignment system allows a direct detection of alignment marks both on front-side and back-side of wafer, and consequently allows feasible micro-fabrication for 3D interconnect using the reversed wafer. A combination of the optical direct-writing exposure tool of Dainippon Screen MFG. Co., Ltd. with the reflective IR alignment system and a high aspect chemically amplified resist of Tokyo Ohka Kogyo Co., Ltd. provides the lithography process exclusively for 12-inch wafer level 3D interconnect.

  9. Theoretical description of two ultracold atoms in finite three-dimensional optical lattices using realistic interatomic interaction potentials

    SciTech Connect

    Grishkevich, Sergey; Sala, Simon; Saenz, Alejandro

    2011-12-15

    A theoretical approach is described for an exact numerical treatment of a pair of ultracold atoms interacting via a central potential and that are trapped in a finite three-dimensional optical lattice. The coupling of center-of-mass and relative-motion coordinates is treated using an exact diagonalization (configuration-interaction) approach. The orthorhombic symmetry of an optical lattice with three different but orthogonal lattice vectors is explicitly considered as is the fermionic or bosonic symmetry in the case of indistinguishable particles.

  10. Holographically formed three-dimensional Penrose-type photonic quasicrystal through a lab-made single diffractive optical element.

    PubMed

    Harb, Ahmad; Torres, Faraon; Ohlinger, Kris; Lin, Yuankun; Lozano, Karen; Xu, Di; Chen, Kevin P

    2010-09-13

    Large-area three-dimensional Penrose-type photonic quasicrystals are fabricated through a holographic lithography method using a lab-made diffractive optical element and a single laser exposure. The diffractive optical element consists of five polymer gratings symmetrically orientated around a central opening. The fabricated Penrose-type photonic quasicrystal shows ten-fold rotational symmetry. The Laue diffraction pattern from the photonic quasi-crystal is observed to be similar to that of the traditional alloy quasi-crystal. A golden ratio of 1.618 is also observed for the radii of diffraction rings, which has not been observed before in artificial photonic quasicrystals.

  11. Fractal frequency spectrum in laser resonators and three-dimensional geometric topology of optical coherent waves

    NASA Astrophysics Data System (ADS)

    Tung, J. C.; Tuan, P. H.; Liang, H. C.; Huang, K. F.; Chen, Y. F.

    2016-08-01

    We theoretically verify that the symmetry breaking in spherical resonators can result in a fractal frequency spectrum that is full of numerous new accidental degeneracies to cluster around the unperturbed degenerate cavity. We further experimentally discover that the fractal frequency spectrum excellently reflects the intimate connection between the emission power and the degenerate mode numbers. It is observed that the wave distributions of lasing modes at the accidental degeneracies are strongly concentrated on three-dimensional (3D) geometric topology. Considering the overlapping effect, the wave representation of the coherent states is analytically derived to manifest the observed 3D geometric surfaces.

  12. Characteristics of the autostereoscopic three-dimensional LED display based on diffractive optical elements sheet

    NASA Astrophysics Data System (ADS)

    Su, Ping; An, Pengli; Ma, Jianshe; An, Shu; Cao, Liangcai

    2016-10-01

    Research on the characteristic of the autostereoscopic LED display (ALEDD) using DOEs sheet is of prime importance to the widely application of the (ALEDD). In this paper, the effects caused by the assembling errors between the LED display and DOEs sheet are theoretically and experimentally analyzed. The results show that, the tolerance assembling errors are | Δ z |<= 1mm , and, Δθ Δθ <= 1°, respectively. This conclusion will benefit a lot in instructing the installation of the autostereoscopic three-dimensional LED display system to reduce the crosstalk and improve the quality of 3D perception.

  13. Three-dimensional imaging of eye surface pathologies and contact lens fit with high resolution spectral optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Wojtkowski, M.; Kałużny, B.; Szkulmowska, A.; Bajraszewski, T.; Szkulmowski, M.; Targowski, P.; Kowalczyk, A.

    2007-02-01

    Purpose: To show potential of Spectral Optical Coherence Tomography system for high resolution, cross-sectional and three-dimensional imaging of eye surface pathologies. Methods: High-speed spectral OCT prototype instrument with 4.5 μm axial resolution was designed and constructed for clinical use. Measurements of anterior segment of human eye have been performed in ophthalmology clinic on 86 patients suffering various eye surface disorders including corneal dystrophies, corneal scars, conjunctival folds, keratoconus, bullus keratopathy, filtration blebs and other post-operative changes. Additionally, examinations of contact lens fit on 97 healthy corneas have been performed up to date. Results: High quality, high resolution cross-sectional images and three-dimensional reconstructions of cornea, conjunctiva and sclera of pathologic eyes together with examples of numerical analysis including segmentation of fluid in filtration blebs, scars and deposits are shown. Quantitative analysis of contact lens fit is demonstrated.

  14. Image formation of holographic three-dimensional display based on spatial light modulator in paraxial optical systems

    NASA Astrophysics Data System (ADS)

    Li, Junchang; Lin, Yu-Chih; Tu, Han-Yen; Gui, Jinbin; Li, Chongguang; Lou, Yuli; Cheng, Chau-Jern

    2015-10-01

    This work describes the image formation and properties of holographic three-dimensional (3-D) display based on spatial light modulators (SLMs) combined with optical imaging systems. Existing pixelated SLMs with periodic mesh structures affect the holographic reconstruction and display properties. According to a holographic 3-D display architecture based on SLM in paraxial optical systems, this study applied the ray matrix optics and scalar diffraction theory to regard the light wave emitting from the holographic plane to the image plane as an optical system composed of four matrix elements. The image quality and depth of field (DOF) of the holographic 3-D display system are investigated, and the relationship between the impulse response and the matrix elements of the holographic imaging system is derived. In addition, the imaging properties and DOF are explored and verified through optical experimentation.

  15. X-ray guided three-dimensional diffuse optical tomography: in vivo study of osteoarthritis in the finger joints

    NASA Astrophysics Data System (ADS)

    Zhang, Qizhi; Yuan, Zhen; Sobel, Eric; Jiang, Huabei

    2007-02-01

    Osteoarthritis (OA), characterized by the damage of the articular cartilage, is the most common joint problem worldwide. In the effort of developing new clinical tools with the potential to alter the natural history of OA, near-infrared diffuse optical tomography (DOT) has received much attention due to its unique advantages. For optical imaging in highly heterogeneous media such as the finger joints, prior information could improve the quality of optical imaging. We report a hybrid imaging system for early detection of OA in the finger joints by imposing the geometry information obtained by X-ray on three-dimensional near-infrared DOT. X-ray tomosynthesis was employed to recover the three-dimensional structure of the two bones based on 16 X-ray projections generated with a mini C-arm system at different directions within a range of 180 degrees. The interface was carefully designed to guarantee an accurate co-registration of the optical and x-ray modalities. The prior structural information of bones was incorporated into our multi-modality imaging reconstruction algorithm to enhance the recovery of the optical properties of joint tissues. Several healthy and OA finger joints were examined. The initial clinical results showed that this hybrid imaging system had the ability to provide much enhanced image resolution and contrast than DOT alone for OA detection.

  16. Three-dimensional negative index of refraction at optical frequencies by coupling plasmonic waveguides.

    PubMed

    Verhagen, Ewold; de Waele, René; Kuipers, L; Polman, Albert

    2010-11-26

    We identify a route towards achieving a negative index of refraction at optical frequencies based on coupling between plasmonic waveguides that support backwards waves. We show how modal symmetry can be exploited in metal-dielectric waveguide pairs to achieve negative refraction of both phase and energy. Control of waveguide coupling yields a metamaterial consisting of a one-dimensional multilayer stack that exhibits an isotropic index of -1 at a free-space wavelength of 400 nm. The concepts developed here may inspire new low-loss metamaterial designs operating close to the metal plasma frequency.

  17. Three-dimensional controlled growth of monodisperse sub-50 nm heterogeneous nanocrystals

    PubMed Central

    Liu, Deming; Xu, Xiaoxue; Du, Yi; Qin, Xian; Zhang, Yuhai; Ma, Chenshuo; Wen, Shihui; Ren, Wei; Goldys, Ewa M.; Piper, James A.; Dou, Shixue; Liu, Xiaogang; Jin, Dayong

    2016-01-01

    The ultimate frontier in nanomaterials engineering is to realize their composition control with atomic scale precision to enable fabrication of nanoparticles with desirable size, shape and surface properties. Such control becomes even more useful when growing hybrid nanocrystals designed to integrate multiple functionalities. Here we report achieving such degree of control in a family of rare-earth-doped nanomaterials. We experimentally verify the co-existence and different roles of oleate anions (OA−) and molecules (OAH) in the crystal formation. We identify that the control over the ratio of OA− to OAH can be used to directionally inhibit, promote or etch the crystallographic facets of the nanoparticles. This control enables selective grafting of shells with complex morphologies grown over nanocrystal cores, thus allowing the fabrication of a diverse library of monodisperse sub-50 nm nanoparticles. With such programmable additive and subtractive engineering a variety of three-dimensional shapes can be implemented using a bottom–up scalable approach. PMID:26743184

  18. Induced thermal stress fields for three-dimensional distortion control of Si wafer topography

    NASA Astrophysics Data System (ADS)

    Schaper, Charles D.; Chen, Been-Der; Pease, R. Fabian W.

    2004-06-01

    Localized, controlled heating can induce a thermal stress field in silicon wafers and displace the surface topography in three dimensions, which is useful for nanoscale regulation of overlay in microcontact printing systems. Simulation and experimental results are presented to demonstrate the use of a thermal array consisting of a dense distribution of independent heating elements to locally displace silicon wafer alignment microstructures. An experimental apparatus comprised of a 7×7 array of thermal cycling sources is used to control the absolute three-dimensional position of surface microstructures. The system is used to demonstrate out-of-plane sensitivity of 1.4 μm/°C by thermomechanical displacement contributions from thermal expansion of the heating element. Rolloff in out-of-plane displacement of 200 nm/mm/°C in silicon at the boundary between heated and nonheated regions in this apparatus is exhibited. Dynamic real-time control of the substrate flatness is thus feasible and is demonstrated with the apparatus using feedback from three alignment microscopes, to sub-100 nm levels of regulation. Control of the in-plane microstructure position is achieved by stabilizing the vertical displacement with a mechanical nanopositioning stage, while establishing a thermal stress field to produce displacement sensitivity of 70 nm/°C. Real-time feedback control of the in-plane microstructure position is demonstrated, also within sub-100 nm of the target regulation level.

  19. Three-dimensional deployment of electro-dynamic tether via tension and current control with constraints

    NASA Astrophysics Data System (ADS)

    Wen, Hao; Jin, Dongping; Hu, Haiyan

    2016-12-01

    The concept of space tether has found a great deal of promising applications in space engineering. A prerequisite of any space tether mission is to deploy its tether to a commanded length. This paper aims to achieving the three-dimensional deployment of an electro-dynamic tether system in a propellant-free manner via the feedback control of the tension and electric current in the tether. The proposed controller is formulated in an analytical form with an extremely low level of computational load, and can explicitly account for the physical bounds of the tether tension and electric current by using a pair of strictly increasing saturation functions. In addition, the Lyapunov analysis is made to gain an insight into the stability characteristics of the proposed control strategy. To facilitate the theoretical analysis, the dynamic model of the system is developed under the widely used dumbbell assumption, along with the geomagnetic field modeled using a tilted dipole approximation. Finally, numerical case studies on a representative electro-dynamic tether system are conducted to evaluate the performance of the proposed controller and the influence of the actuating conditions and orbital inclinations.

  20. Three-dimensional light distribution near the focus of a tightly focused beam of few-cycle optical pulses

    SciTech Connect

    Romallosa, Kristine Marie; Bantang, Johnrob; Saloma, Caesar

    2003-09-01

    Via the Richards-Wolf vector diffraction theory, we analyze the three-dimensional intensity distribution of the focal volume that is produced by a strongly focused 750-nm beam of ultrafast, Gaussian-shaped optical pulses (10{sup -9} s{>=} pulse width {tau}{>=}1 fs=10{sup -15} s). Knowledge of the three-dimensional distribution near focus is essential in determining the diffraction-limited resolution of an optical microscope. The optical spectrum of a short pulse is characterized by side frequencies about the carrier frequency. The effect of spectral broadening on the focused intensity distribution is evaluated via the Linfoot's criteria of fidelity, structural content, and correlation quality and with reference to a 750-nm cw focused beam. Different values are considered for {tau} and numerical aperture of the focusing lens (0.1{<=}X{sub NA}{<=}1.2). At X{sub NA}=0.8, rapid deterioration of the focused intensity distribution is observed at {tau}=1.2 fs. This happens because a 750-nm optical pulse with {tau}=1.2 fs has an associated coherence length of 359.7 nm which is less than the Nyquist sampling interval of 375 nm that is required to sample 750 nm sinusoid without loss of information. The ill-effects of spectral broadening is weaker in two-photon excitation microscope than in its single-photon counterpart for the same focusing lens and light source.

  1. Collisions of three-dimensional bipolar optical solitons in an array of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zhukov, Alexander V.; Bouffanais, Roland; Malomed, Boris A.; Leblond, Hervé; Mihalache, Dumitru; Fedorov, Eduard G.; Rosanov, Nikolay N.; Belonenko, Mikhail B.

    2016-11-01

    We study interactions of extremely short three-dimensional bipolar electromagnetic pulses propagating towards each other in an array of semiconductor carbon nanotubes, along any direction perpendicular to their axes. The analysis provides a full account of the effects of the nonuniformity of the pulses' fields along the axes. The evolution of the electromagnetic field and charge density in the sample is derived from the Maxwell's equations and the continuity equation, respectively. In particular, we focus on indirect interaction of the pulses via the action of their fields on the electronic subsystem of the nanotube array. Changes in the shape of pulses in the course of their propagation and interaction are analyzed by calculating and visualizing the distribution of the electric field in the system. The numerical analysis reveals a possibility of stable post-collision propagation of pulses over distances much greater than their sizes.

  2. Incomplete optical shielding in cold atom traps: three-dimensional Landau-Zener theory

    SciTech Connect

    Yurovsky, V.A.; Ben-Reuven, A.

    1997-05-01

    Ultracold atom collisions in the presence of a linearly polarized blueshifted laser field are studied theoretically. An analytical solution is presented within the framework of the Landau-Zener approximation. The effect of incomplete shielding is mostly accounted for by incorporating the three-dimensional character of the collisions, using a partial-wave analysis with space degeneracy. A model of two electronic states, including effects of indistinguishability of the colliding atoms, is used. The model associates the incomplete shielding with a process involving two crossing points. The theory is applied to the case of metastable xenon traps, obtaining a fair agreement with the experimental data. {copyright} {ital 1997} {ital The American Physical Society}

  3. Stability and Control of Constrained Three-Dimensional Robotic Systems with Application to Bipedal Postural Movements

    NASA Astrophysics Data System (ADS)

    Kallel, Hichem

    Three classes of postural adjustments are investigated with the view of a better understanding of the control mechanisms involved in human movement. The control mechanisms and responses of human or computer models to deliberately induced disturbances in postural adjustments are the focus of this dissertation. The classes of postural adjustments are automatic adjustments, (i.e. adjustments not involving voluntary deliberate movement), adjustments involving imposition of constraints for the purpose of maintaining support forces, and adjustments involving violation and imposition of constraints for the purpose of maintaining balance, (i.e. taking one or more steps). For each class, based on the physiological attributes of the control mechanisms in human movements, control strategies are developed to synthesize the desired postural response. The control strategies involve position and velocity feedback control, on line relegation control, and pre-stored trajectory control. Stability analysis for constrained and unconstrained maneuvers is carried out based on Lyapunov stability theorems. The analysis is based on multi-segment biped robots. Depending on the class of postural adjustments, different biped models are developed. An eight-segment three dimensional biped model is formulated for the study of automatic adjustments and adjustments for balance. For the study of adjustments for support, a four segment lateral biped model is considered. Muscle synergies in automatic adjustments are analyzed based on a three link six muscle system. The muscle synergies considered involve minimal muscle number and muscle co-activation. The role of active and passive feedback in these automatic adjustments is investigated based on the specified stiffness and damping of the segments. The effectiveness of the control strategies and the role of muscle synergies in automatic adjustments are demonstrated by a number of digital computer simulations.

  4. Three-dimensional control of light in a two-dimensional photonic crystal slab.

    PubMed

    Chow, E; Lin, S Y; Johnson, S G; Villeneuve, P R; Joannopoulos, J D; Wendt, J R; Vawter, G A; Zubrzycki, W; Hou, H; Alleman, A

    2000-10-26

    Optoelectronic devices are increasingly important in communication and information technology. To achieve the necessary manipulation of light (which carries information in optoelectronic devices), considerable efforts are directed at the development of photonic crystals--periodic dielectric materials that have so-called photonic bandgaps, which prohibit the propagation of photons having energies within the bandgap region. Straightforward application of the bandgap concept is generally thought to require three-dimensional (3D) photonic crystals; their two-dimensional (2D) counterparts confine light in the crystal plane, but not in the perpendicular z direction, which inevitably leads to diffraction losses. Nonetheless, 2D photonic crystals still attract interest because they are potentially more amenable to fabrication by existing techniques and diffraction losses need not seriously impair utility. Here we report the fabrication of a waveguide-coupled photonic crystal slab (essentially a free-standing 2D photonic crystal) with a strong 2D bandgap at wavelengths of about 1.5 microm, yet which is capable of fully controlling light in all three dimensions. These features confirm theoretical calculations on the possibility of achieving 3D light control using 2D bandgaps, with index guiding providing control in the third dimension, and raise the prospect of being able to realize unusual photonic-crystal devices, such as thresholdless lasers.

  5. Shape-controlled synthesis of hybrid nanomaterials via three-dimensional hydrodynamic focusing.

    PubMed

    Lu, Mengqian; Yang, Shikuan; Ho, Yi-Ping; Grigsby, Christopher L; Leong, Kam W; Huang, Tony Jun

    2014-10-28

    Shape-controlled synthesis of nanomaterials through a simple, continuous, and low-cost method is essential to nanomaterials research toward practical applications. Hydrodynamic focusing, with its advantages of simplicity, low-cost, and precise control over reaction conditions, has been used for nanomaterial synthesis. While most studies have focused on improving the uniformity and size control, few have addressed the potential of tuning the shape of the synthesized nanomaterials. Here we demonstrate a facile method to synthesize hybrid materials by three-dimensional hydrodynamic focusing (3D-HF). While keeping the flow rates of the reagents constant and changing only the flow rate of the buffer solution, the molar ratio of two reactants (i.e., tetrathiafulvalene (TTF) and HAuCl4) within the reaction zone varies. The synthesized TTF-Au hybrid materials possess very different and predictable morphologies. The reaction conditions at different buffer flow rates are studied through computational simulation, and the formation mechanisms of different structures are discussed. This simple one-step method to achieve continuous shape-tunable synthesis highlights the potential of 3D-HF in nanomaterials research.

  6. Gesture-controlled interactive three dimensional anatomy: a novel teaching tool in head and neck surgery.

    PubMed

    Hochman, Jordan B; Unger, Bertram; Kraut, Jay; Pisa, Justyn; Hombach-Klonisch, Sabine

    2014-01-01

    There is a need for innovative anatomic teaching tools. This paper describes a three dimensional (3D) tool employing the Microsoft Kinect™. Using this instrument, 3D temporal bone anatomy can be manipulated with the use of hand gestures, in the absence of mouse or keyboard. CT Temporal bone data is imported into an image processing program and segmented. This information is then exported in polygonal mesh format to an in-house designed 3D graphics engine with an integrated Microsoft Kinect™. Motion in the virtual environment is controlled by tracking hand position relative to the user's left shoulder. The tool successfully tracked scene depth and user joint locations. This permitted gesture-based control over the entire 3D environment. Stereoscopy was deemed appropriate with significant object projection, while still maintaining the operator's ability to resolve image details. Specific anatomical structures can be selected from within the larger virtual environment. These structures can be extracted and rotated at the discretion of the user. Voice command employing the Kinect's™ intrinsic speech library was also implemented, but is easily confounded by environmental noise. There is a need for the development of virtual anatomy models to complement traditional education. Initial development is time intensive. Nonetheless, our novel gesture-controlled interactive 3D model of the temporal bone represents a promising interactive teaching tool utilizing a novel interface.

  7. Stability and collapse of localized solutions of the controlled three-dimensional Gross-Pitaevskii equation

    NASA Astrophysics Data System (ADS)

    Fedele, R.; Jovanović, D.; Eliasson, B.; de Nicola, S.; Shukla, P. K.

    2010-03-01

    On the basis of recent investigations, a newly developed analytical procedure is used for constructing a wide class of localized solutions of the controlled three-dimensional (3D) Gross-Pitaevskii equation (GPE) that governs the dynamics of Bose-Einstein condensates (BECs) in the presence of a spatio-temporally varying external potential. The controlled 3D GPE is decomposed into a two-dimensional (2D) linear Schrödinger equation (called the `transverse equation’) and a one-dimensional (1D) nonlinear Schrödinger equation (called the `longitudinal equation’), constrained by a variational condition for the controlling potential. The latter corresponds to the requirement for the minimization of the control operation in the transverse plane. Then, the above class of localized solutions are constructed as the product of the solutions of the transverse and longitudinal equations. A consistency condition between the transverse and longitudinal solutions yields a relationship between the transverse and longitudinal restoring forces produced by the external trapping potential well through a `controlling parameter’ (i.e. the average, with respect to the transverse profile, of the nonlinear inter-atomic interaction term of the GPE). It is found that the longitudinal profile supports localized solutions in the form of bright, dark or grey solitons with time-dependent amplitudes, widths and centroids. The related longitudinal phase is varying in space and time with time-dependent curvature radius and wavenumber. In turn, all the above parameters (i.e. amplitudes, widths, centroids, curvature radius and wavenumbers) can be easily expressed in terms of the controlling parameter. It is also found that the transverse profile has the form of Hermite-Gauss functions (depending on the transverse coordinates), and the explicit spatio-temporal dependence of the controlling potential is self-consistently determined. On the basis of these exact 3D analytical solutions, a stability

  8. Controllable load sharing for soft adhesive interfaces on three-dimensional surfaces

    NASA Astrophysics Data System (ADS)

    Song, Sukho; Drotlef, Dirk-Michael; Majidi, Carmel; Sitti, Metin

    2017-05-01

    For adhering to three-dimensional (3D) surfaces or objects, current adhesion systems are limited by a fundamental trade-off between 3D surface conformability and high adhesion strength. This limitation arises from the need for a soft, mechanically compliant interface, which enables conformability to nonflat and irregularly shaped surfaces but significantly reduces the interfacial fracture strength. In this work, we overcome this trade-off with an adhesion-based soft-gripping system that exhibits enhanced fracture strength without sacrificing conformability to nonplanar 3D surfaces. Composed of a gecko-inspired elastomeric microfibrillar adhesive membrane supported by a pressure-controlled deformable gripper body, the proposed soft-gripping system controls the bonding strength by changing its internal pressure and exploiting the mechanics of interfacial equal load sharing. The soft adhesion system can use up to ˜26% of the maximum adhesion of the fibrillar membrane, which is 14× higher than the adhering membrane without load sharing. Our proposed load-sharing method suggests a paradigm for soft adhesion-based gripping and transfer-printing systems that achieves area scaling similar to that of a natural gecko footpad.

  9. Controlling collagen fiber microstructure in three-dimensional hydrogels using ultrasound

    PubMed Central

    Garvin, Kelley A.; VanderBurgh, Jacob; Hocking, Denise C.; Dalecki, Diane

    2013-01-01

    Type I collagen is the primary fibrillar component of the extracellular matrix, and functional properties of collagen arise from variations in fiber structure. This study investigated the ability of ultrasound to control collagen microstructure during hydrogel fabrication. Under appropriate conditions, ultrasound exposure of type I collagen during polymerization altered fiber microstructure. Scanning electron microscopy and second-harmonic generation microscopy revealed decreased collagen fiber diameters in response to ultrasound compared to sham-exposed samples. Results of mechanistic investigations were consistent with a thermal mechanism for the effects of ultrasound on collagen fiber structure. To control collagen microstructure site-specifically, a high frequency, 8.3-MHz, ultrasound beam was directed within the center of a large collagen sample producing dense networks of short, thin collagen fibrils within the central core of the gel and longer, thicker fibers outside the beam area. Fibroblasts seeded onto these gels migrated rapidly into small, circularly arranged aggregates only within the beam area, and clustered fibroblasts remodeled the central, ultrasound-exposed collagen fibrils into dense sheets. These investigations demonstrate the capability of ultrasound to spatially pattern various collagen microstructures within an engineered tissue noninvasively, thus enhancing the level of complexity of extracellular matrix microenvironments and cellular functions achievable within three-dimensional engineered tissues. PMID:23927189

  10. Three Dimensional Solution of Pneumatic Active Control of Forebody Vortex Asymmetry

    NASA Technical Reports Server (NTRS)

    Kandil, Osama A.; SharafEl-Din, Hazem H.; Liu, C. H.

    1995-01-01

    Pneumatic active control of asymmetric vortical flows around a slender pointed forebody is investigated using the three dimensional solution for the compressible thin-layer Navier-Stokes equation. The computational applications cover the normal and tangential injection control of asymmetric flows around a 5 degree semi-apex angle cone at a 40 degree angle of attack, 1.4 freestream Mach number and 6 x 10(exp 6) freestream Reynolds number (based on the cone length). The effective tangential angle range of 67.5 approaches minus 67.5 degrees is used for both normal and tangential ports of injection. The effective axial length of injection is varied from 0.03 to 0.05. The computational solver uses the implicit, upwind, flux difference splitting finite volume scheme, and the grid consists of 161 x 55 x 65 points in the wrap around, normal and axial directions, respectively. The results show that tangential injection is more effective than normal injection.

  11. Coordinated Control of Three-Dimensional Components of Smooth Pursuit to Rotating and Translating Textures.

    PubMed

    Edinger, Janick; Pai, Dinesh K; Spering, Miriam

    2017-01-01

    The neural control of pursuit eye movements to visual textures that simultaneously translate and rotate has largely been neglected. Here we propose that pursuit of such targets-texture pursuit-is a fully three-dimensional task that utilizes all three degrees of freedom of the eye, including torsion. Head-fixed healthy human adults (n = 8) tracked a translating and rotating random dot pattern, shown on a computer monitor, with their eyes. Horizontal, vertical, and torsional eye positions were recorded with a head-mounted eye tracker. The torsional component of pursuit is a function of the rotation of the texture, aligned with its visual properties. We observed distinct behaviors between those trials in which stimulus rotation was in the same direction as that of a rolling ball ("natural") in comparison to those with the opposite rotation ("unnatural"): Natural rotation enhanced and unnatural rotation reversed torsional velocity during pursuit, as compared to torsion triggered by a nonrotating random dot pattern. Natural rotation also triggered pursuit with a higher horizontal velocity gain and fewer and smaller corrective saccades. Furthermore, we show that horizontal corrective saccades are synchronized with torsional corrective saccades, indicating temporal coupling of horizontal and torsional saccade control. Pursuit eye movements have a torsional component that depends on the visual stimulus. Horizontal and torsional eye movements are separated in the motor periphery. Our findings suggest that translational and rotational motion signals might be coordinated in descending pursuit pathways.

  12. Cell volume control at a surface for three-dimensional grid generation packages

    NASA Technical Reports Server (NTRS)

    Alter, Stephen J.; Weilmuenster, Kenneth J.

    1992-01-01

    An alternate method of calculating the cell size for orthogonality control in the solution of Poisson's 3D space equations is presented. The method provides the capability to enforce a better initial guess for the grid distribution required for boundary layer resolution. This grid point distribution is accomplished by enforcing grid spacing from a grid block boundary where orthogonality is required. The actual grid spacing or cell size for that boundary is determined by the two or four adjacent boundaries in the grid block definition, which are two dimensional grids. These two dimensional grids are in turn defined by the user using insight into the flow field and boundary layer characteristics. The adjoining boundaries are extended using a multifunctional blending scheme, with user control of the blending and interpolating functions to be used. This grid generation procedure results in an enhanced computational fluid dynamics calculation by allowing a quicker resolution of the configuration's boundary layer and flow field and by limiting the number of grid re-adaptations. The cell size specification calculation was applied to a variety of configurations ranging from axisymmetric to complex three-dimensional configurations. Representative grids are shown for the Space Shuttle and the Langley Lifting Body (HL-20).

  13. Controllable load sharing for soft adhesive interfaces on three-dimensional surfaces

    PubMed Central

    Song, Sukho; Drotlef, Dirk-Michael; Majidi, Carmel; Sitti, Metin

    2017-01-01

    For adhering to three-dimensional (3D) surfaces or objects, current adhesion systems are limited by a fundamental trade-off between 3D surface conformability and high adhesion strength. This limitation arises from the need for a soft, mechanically compliant interface, which enables conformability to nonflat and irregularly shaped surfaces but significantly reduces the interfacial fracture strength. In this work, we overcome this trade-off with an adhesion-based soft-gripping system that exhibits enhanced fracture strength without sacrificing conformability to nonplanar 3D surfaces. Composed of a gecko-inspired elastomeric microfibrillar adhesive membrane supported by a pressure-controlled deformable gripper body, the proposed soft-gripping system controls the bonding strength by changing its internal pressure and exploiting the mechanics of interfacial equal load sharing. The soft adhesion system can use up to ∼26% of the maximum adhesion of the fibrillar membrane, which is 14× higher than the adhering membrane without load sharing. Our proposed load-sharing method suggests a paradigm for soft adhesion-based gripping and transfer-printing systems that achieves area scaling similar to that of a natural gecko footpad. PMID:28507143

  14. Assembling of three-dimensional crystals by optical depletion force induced by a single focused laser beam.

    PubMed

    Deng, Hai-Dong; Li, Guang-Can; Liu, Hai-Ying; Dai, Qiao-Feng; Wu, Li-Jun; Lan, Sheng; Gopal, Achanta Venu; Trofimov, Vyacheslav A; Lysak, Tatiana M

    2012-04-23

    We proposed a method to assemble microspheres into a three-dimensional crystal by utilizing the giant nonequilibrium depletion force produced by nanoparticles. Such assembling was demonstrated in a colloid formed by suitably mixing silica microspheres and magnetic nanoparticles. The giant nonequilibrium depletion force was generated by quickly driving magnetic nanoparticles out of the focusing region of a laser light through both optical force and thermophoresis. The thermophoretic binding of silica beads is so tight that a colloidal photonic crystal can be achieved after complete evaporation of solvent. This technique could be employed for fabrication of colloidal photonic crystals and molecular sieves.

  15. Three-dimensional light-scattering and deformation of individual biconcave human blood cells in optical tweezers.

    PubMed

    Yu, Lingyao; Sheng, Yunlong; Chiou, Arthur

    2013-05-20

    For studying the elastic properties of a biconcave red blood cell using the dual-trap optical tweezers without attaching microbeads to the cell, we implemented a three-dimensional finite element simulation of the light scattering and cell's deformation using the coupled electromagnetic and continuum mechanics modules. We built the vector field of the trapping beams, the cell structure layout, the hyperelastic and viscoelastic cell materials, and we reinforced the constraints on the cell constant volume in the simulation. This computation model can be useful for studying the scattering and the other mechanical properties of the biological cells.

  16. Reconstruction of mechanically recorded sound from an edison cylinder using three dimensional non-contact optical surface metrology

    SciTech Connect

    Fadeyev, V.; Haber, C.; Maul, C.; McBride, J.W.; Golden, M.

    2004-04-20

    Audio information stored in the undulations of grooves in a medium such as a phonograph disc record or cylinder may be reconstructed, without contact, by measuring the groove shape using precision optical metrology methods and digital image processing. The viability of this approach was recently demonstrated on a 78 rpm shellac disc using two dimensional image acquisition and analysis methods. The present work reports the first three dimensional reconstruction of mechanically recorded sound. The source material, a celluloid cylinder, was scanned using color coded confocal microscopy techniques and resulted in a faithful playback of the recorded information.

  17. Optical absorption enhancement with low structural-parameter sensitivity in three-dimensional silicon nanocavity array for solar photovoltaics

    NASA Astrophysics Data System (ADS)

    Zhang, Fuqiang; Sun, Ruinan; Hu, Ya; Peng, Kui-Qing

    2016-01-01

    Effective light trapping is essential for improving the efficiency and reducing the cost of thin-film silicon solar cells. Here, we numerically study the optical characteristics of periodic three-dimensional (3D) silicon nanocavity arrays. We found that the 3D silicon nanocavity array shows low sensitivity to geometric structural parameters for photon capture and achieves an outstanding efficiency superior to those of previously reported silicon nanostructures such as a nanowire and a nanohole with the same thickness. This excellence is attributed to a better antireflection capability and more resonant modes. The 3D silicon nanocavity array provides a new light-trapping strategy for thin-film photovoltaic devices.

  18. Three-dimensional phase transformation by impedance-matched dielectric slabs and generation of hollow beams based on transformation optics

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Yang, Shuaisai; Tang, Zhixiang; Shu, Weixing

    2016-10-01

    We propose a three-dimensional (3D) phase transformation method by an impedance-matched dielectric slab and apply it to generating hollow beams. We first employ transformation optics to establish a method for the transformation between two arbitrary 3D wavefronts through a flat dielectric and impedance-matched material. Then the method is used to convert a solid beam into a hollow beam with desired wavefront. By tuning the transformation surface, different hollow beams can be produced. The results are further validated by 3D finite-difference time-domain simulations.

  19. Modeling, Control and Simulation of Three-Dimensional Robotic Systems with Applications to Biped Locomotion.

    NASA Astrophysics Data System (ADS)

    Zheng, Yuan-Fang

    A three-dimensional, five link biped system is established. Newton-Euler state space formulation is employed to derive the equations of the system. The constraint forces involved in the equations can be eliminated by projection onto a smaller state space system for deriving advanced control laws. A model-referenced adaptive control scheme is developed to control the system. Digital computer simulations of point to point movement are carried out to show that the model-referenced adaptive control increases the dynamic range and speeds up the response of the system in comparison with linear and nonlinear feedback control. Further, the implementation of the controller is simpler. Impact effects of biped contact with the environment are modeled and studied. The instant velocity change at the moment of impact is derived as a function of the biped state and contact speed. The effects of impact on the state, as well as constraints are studied in biped landing on heels and toes simultaneously or on toes first. Rate and nonlinear position feedback are employed for stability of the biped after the impact. The complex structure of the foot is properly modeled. A spring and dashpot pair is suggested to represent the action of plantar fascia during the impact. This action prevents the arch of the foot from collapsing. A mathematical model of the skeletal muscle is discussed. A direct relationship between the stimulus rate and the active state is established. A piecewise linear relation between the length of the contractile element and the isometric force is considered. Hill's characteristic equation is maintained for determining the actual output force during different shortening velocities. A physical threshold model is proposed for recruitment which encompasses the size principle, its manifestations and exceptions to the size principle. Finally the role of spindle feedback in stability of the model is demonstrated by study of a pair of muscles.

  20. Identification of muscle necrosis in the mdx mouse model of Duchenne muscular dystrophy using three-dimensional optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Klyen, Blake R.; Shavlakadze, Thea; Radley-Crabb, Hannah G.; Grounds, Miranda D.; Sampson, David D.

    2011-07-01

    Three-dimensional optical coherence tomography (3D-OCT) was used to image the structure and pathology of skeletal muscle tissue from the treadmill-exercised mdx mouse model of human Duchenne muscular dystrophy. Optical coherence tomography (OCT) images of excised muscle samples were compared with co-registered hematoxylin and eosin-stained and Evans blue dye fluorescence histology. We show, for the first time, structural 3D-OCT images of skeletal muscle dystropathology well correlated with co-located histology. OCT could identify morphological features of interest and necrotic lesions within the muscle tissue samples based on intrinsic optical contrast. These findings demonstrate the utility of 3D-OCT for the evaluation of small-animal skeletal muscle morphology and pathology, particularly for studies of mouse models of muscular dystrophy.

  1. SPIRALING OUT OF CONTROL: THREE-DIMENSIONAL HYDRODYNAMICAL MODELING OF THE COLLIDING WINDS IN {eta} CARINAE

    SciTech Connect

    Parkin, E. R.; Pittard, J. M.; Corcoran, M. F.; Hamaguchi, K.

    2011-01-10

    Three-dimensional adaptive mesh refinement hydrodynamical simulations of the wind-wind collision between the enigmatic supermassive star {eta} Car and its mysterious companion star are presented which include radiative driving of the stellar winds, gravity, optically thin radiative cooling, and orbital motion. Simulations with static stars with a periastron passage separation reveal that the preshock companion star's wind speed is sufficiently reduced so that radiative cooling in the postshock gas becomes important, permitting the runaway growth of nonlinear thin-shell instabilities (NTSIs) which massively distort the wind-wind collision region (WCR). However, large-scale simulations, which include the orbital motion of the stars, show that orbital motion reduces the impact of radiative inhibition and thus increases the acquired preshock velocities. As such, the postshock gas temperature and cooling time see a commensurate increase, and sufficient gas pressure is preserved to stabilize the WCR against catastrophic instability growth. We then compute synthetic X-ray spectra and light curves and find that, compared to previous models, the X-ray spectra agree much better with XMM-Newton observations just prior to periastron. The narrow width of the 2009 X-ray minimum can also be reproduced. However, the models fail to reproduce the extended X-ray minimum from previous cycles. We conclude that the key to explaining the extended X-ray minimum is the rate of cooling of the companion star's postshock wind. If cooling is rapid then powerful NTSIs will heavily disrupt the WCR. Radiative inhibition of the companion star's preshock wind, albeit with a stronger radiation-wind coupling than explored in this work, could be an effective trigger.

  2. Spin injection and helicity control of surface spin photocurrent in a three dimensional topological insulator

    PubMed Central

    Huang, Y. Q.; Song, Y. X.; Wang, S. M.; Buyanova, I. A.; Chen, W. M.

    2017-01-01

    A three-dimensional (3D) topological insulator (TI) is a unique quantum phase of matter with exotic physical properties and promising spintronic applications. However, surface spin current in a common 3D TI remains difficult to control and the out-of-plane spin texture is largely unexplored. Here, by means of surface spin photocurrent in Bi2Te3 TI devices driven by circular polarized light, we identify the subtle effect of the spin texture of the topological surface state including the hexagonal warping term on the surface current. By exploring the out-of-plane spin texture, we demonstrate spin injection from GaAs to TI and its significant contribution to the surface current, which can be manipulated by an external magnetic field. These discoveries pave the way to not only intriguing new physics but also enriched spin functionalities by integrating TI with conventional semiconductors, such that spin-enabled optoelectronic devices may be fabricated in such hybrid structures. PMID:28530227

  3. Three-dimensional core-shell hybrid solar cells via controlled in situ materials engineering.

    PubMed

    Mariani, Giacomo; Wang, Yue; Wong, Ping-Show; Lech, Andrew; Hung, Chung-Hong; Shapiro, Joshua; Prikhodko, Sergey; El-Kady, Maher; Kaner, Richard B; Huffaker, Diana L

    2012-07-11

    Three-dimensional core-shell organic-inorganic hybrid solar cells with tunable properties are demonstrated via electropolymerization. Air-stable poly(3,4-ethylenedioxythiophene) (PEDOT) shells with controlled thicknesses are rapidly coated onto periodic GaAs nanopillar arrays conformally, preserving the vertical 3D structure. The properties of the organic layer can be readily tuned in situ, allowing for (1) the lowering of the highest occupied molecular orbital level (|ΔE| ∼ 0.28 eV), leading to the increase of open-circuit voltage (V(OC)), and (2) an improvement in PEDOT conductivity that results in enhanced short-circuit current densities (J(SC)). The incorporation of various anionic dopants in the polymer during the coating process also enables the tailoring of the polymer/semiconductor interface transport properties. Systematic tuning of the device properties results in a J(SC) of 13.6 mA cm(-2), V(OC) of 0.63 V, peak external quantum efficiency of 58.5%, leading to a power conversion efficiencies of 4.11%.

  4. Site-controlled synthesis and mechanism of three-dimensional Mo2S3 flowers

    NASA Astrophysics Data System (ADS)

    Zhong, Yu; Zhang, Yong; Zhang, Gaixia; Li, Ruying; Sun, Xueliang

    2012-12-01

    High-density three-dimensional Mo2S3 flowers have been facilely synthesized with controlled sites by introducing gold particles as the nucleation sites in a chemical vapor deposition process. The whole size of each flower is in micro scale while individual petal has extremely small thickness of around 10 nm. The role of gold particles and precursor concentration in the growth has been carefully investigated. Without gold particles, dense nanopetals were not able to be obtained unless in a highly concentrated sulfur atmosphere. With Au particles, dense products were steadily achieved in a wide precursor concentration range with S:MoO3 molar ratio from 1:5 to 5:1. The morphology and structure of the as-synthesized nanostructures were characterized using field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM). The growth mechanism was proposed in which gold particles acted as the initial nucleation sites fixing the nucleation position of the flowers following vapor-solid growth mechanism.

  5. Matrix mechanics and fluid shear stress control stem cells fate in three dimensional microenvironment.

    PubMed

    Chen, Guobao; Lv, Yonggang; Guo, Pan; Lin, Chongwen; Zhang, Xiaomei; Yang, Li; Xu, Zhiling

    2013-07-01

    Stem cells have the ability to self-renew and to differentiate into multiple mature cell types during early life and growth. Stem cells adhesion, proliferation, migration and differentiation are affected by biochemical, mechanical and physical surface properties of the surrounding matrix in which stem cells reside and stem cells can sensitively feel and respond to the microenvironment of this matrix. More and more researches have proven that three dimensional (3D) culture can reduce the gap between cell culture and physiological environment where cells always live in vivo. This review summarized recent findings on the studies of matrix mechanics that control stem cells (primarily mesenchymal stem cells (MSCs)) fate in 3D environment, including matrix stiffness and extracellular matrix (ECM) stiffness. Considering the exchange of oxygen and nutrients in 3D culture, the effect of fluid shear stress (FSS) on fate decision of stem cells was also discussed in detail. Further, the difference of MSCs response to matrix stiffness between two dimensional (2D) and 3D conditions was compared. Finally, the mechanism of mechanotransduction of stem cells activated by matrix mechanics and FSS in 3D culture was briefly pointed out.

  6. Semiconductor Nanomembrane Tubes: Three-Dimensional Confinement for Controlled Neurite Outgrowth

    PubMed Central

    Yu, Minrui; Huang, Yu; Ballweg, Jason; Shin, Hyuncheol; Huang, Minghuang; Savage, Donald E.; Lagally, Max G.; Dent, Erik W.; Blick, Robert H.; Williams, Justin C.

    2013-01-01

    In many neural culture studies, neurite migration on a flat, open surface does not reflect the three-dimensional (3D) microenvironment in vivo. With that in mind, we fabricated arrays of semiconductor tubes using strained silicon (Si) and germanium (Ge) nanomembranes and employed them as a cell culture substrate for primary cortical neurons. Our experiments show that the SiGe substrate and the tube fabrication process are biologically viable for neuron cells. We also observe that neurons are attracted by the tube topography, even in the absence of adhesion factors, and can be guided to pass through the tubes during outgrowth. Coupled with selective seeding of individual neurons close to the tube opening, growth within a tube can be limited to a single axon. Furthermore, the tube feature resembles the natural myelin, both physically and electrically, and it is possible to control the tube diameter to be close to that of an axon, providing a confined 3D contact with the axon membrane and potentially insulating it from the extracellular solution. PMID:21366271

  7. In vitro three-dimensional bone tissue models: from cells to controlled and dynamic environment.

    PubMed

    Bouet, Guenaelle; Marchat, David; Cruel, Magali; Malaval, Luc; Vico, Laurence

    2015-02-01

    Most of our knowledge of bone cell physiology is derived from experiments carried out in vitro on polystyrene substrates. However, these traditional monolayer cell cultures do not reproduce the complex and dynamic three-dimensional (3D) environment experienced by cells in vivo. Thus, there is a growing interest in the use of 3D culture systems as tools for understanding bone biology. These in-vitro-engineered systems, less complex than in vivo models, should ultimately recapitulate and control the main biophysical, biochemical, and biomechanical cues that define the in vivo bone environment, while allowing their monitoring. This review focuses on state-of-the-art and the current advances in the development of 3D culture systems for bone biology research. It describes more specifically advantages related to the use of such systems, and details main characteristics and challenges associated with its three main components, that is, scaffold, cells, and perfusion bioreactor systems. Finally, future challenges for noninvasive imaging technologies are addressed.

  8. Automatic segmentation in three-dimensional analysis of fibrovascular pigmentepithelial detachment using high-definition optical coherence tomography.

    PubMed

    Ahlers, C; Simader, C; Geitzenauer, W; Stock, G; Stetson, P; Dastmalchi, S; Schmidt-Erfurth, U

    2008-02-01

    A limited number of scans compromise conventional optical coherence tomography (OCT) to track chorioretinal disease in its full extension. Failures in edge-detection algorithms falsify the results of retinal mapping even further. High-definition-OCT (HD-OCT) is based on raster scanning and was used to visualise the localisation and volume of intra- and sub-pigment-epithelial (RPE) changes in fibrovascular pigment epithelial detachments (fPED). Two different scanning patterns were evaluated. 22 eyes with fPED were imaged using a frequency-domain, high-speed prototype of the Cirrus HD-OCT. The axial resolution was 6 mum, and the scanning speed was 25 kA scans/s. Two different scanning patterns covering an area of 6 x 6 mm in the macular retina were compared. Three-dimensional topographic reconstructions and volume calculations were performed using MATLAB-based automatic segmentation software. Detailed information about layer-specific distribution of fluid accumulation and volumetric measurements can be obtained for retinal- and sub-RPE volumes. Both raster scans show a high correlation (p<0.01; R2>0.89) of measured values, that is PED volume/area, retinal volume and mean retinal thickness. Quality control of the automatic segmentation revealed reasonable results in over 90% of the examinations. Automatic segmentation allows for detailed quantitative and topographic analysis of the RPE and the overlying retina. In fPED, the 128 x 512 scanning-pattern shows mild advantages when compared with the 256 x 256 scan. Together with the ability for automatic segmentation, HD-OCT clearly improves the clinical monitoring of chorioretinal disease by adding relevant new parameters. HD-OCT is likely capable of enhancing the understanding of pathophysiology and benefits of treatment for current anti-CNV strategies in future.

  9. Three-dimensional surface measurement based on the projected defocused pattern technique using imaging fiber optics

    NASA Astrophysics Data System (ADS)

    Parra Escamilla, Geliztle A.; Kobayashi, Fumio; Otani, Yukitoshi

    2017-05-01

    We present a three-dimensional surface measurement system using imaging fiber endoscope and the measurement is based on the focus technique in uniaxial configuration. The surface height variation of the sample is retrieved by taking into account the contrast modulation change obtained from a projected fringe pattern on the sample. The technique takes into account the defocus change of the fringe pattern due to the height variation of the sample and by a Gaussian fitting process the height reconstruction can be retrieved. A baseline signal procedure was implemented to remove back reflection light coming from the two fiber-surfaces (inlet and outlet) and also a Fourier transform filter was used to remove the pixelated appearance of the images. The depth range of the system is 1.1 mm and a lateral range of 2 mm by 2 mm. The novelties of the implementation are that the system uses the same imaging fiber as illumination and measurement and offers the advantage of the transportability to the measurement to a confined space having potential application on medical or industrial endoscopes systems. We demonstrate the technique by showing the surface profile of a measured object.

  10. Type-II Weyl points in three-dimensional cold-atom optical lattices

    NASA Astrophysics Data System (ADS)

    Xu, Yong; Duan, L.-M.

    2016-11-01

    Topological Lifshitz phase transition characterizes an abrupt change of the topology of the Fermi surface through a continuous deformation of parameters. Recently, Lifshitz transition has been predicted to separate two types of Weyl points: type-I and type-II (or called structured Weyl points), which has attracted considerable attention in various fields. Although recent experimental investigation has seen a rapid progress on type-II Weyl points, it still remains a significant challenge to observe their characteristic Lifshitz transition. Here, we propose a scheme to realize both type-I and type-II Weyl points in three-dimensional ultracold atomic gases by introducing an experimentally feasible configuration based on current spin-orbit coupling technology. In the resultant Hamiltonian, we find three degenerate points: two Weyl points carrying a Chern number -1 and a fourfold degenerate point carrying a Chern number 2. Remarkably, by continuous tuning of a convenient experimental knob, all these degenerate points can transition from type-I to type-II, thereby providing an ideal platform to study different types of Weyl points and directly probe their Lifshitz phase transition.

  11. Three-dimensional motion correction using speckle and phase for in vivo computed optical interferometric tomography

    PubMed Central

    Shemonski, Nathan D.; Ahn, Shawn S.; Liu, Yuan-Zhi; South, Fredrick A.; Carney, P. Scott; Boppart, Stephen A.

    2014-01-01

    Over the years, many computed optical interferometric techniques have been developed to perform high-resolution volumetric tomography. By utilizing the phase and amplitude information provided with interferometric detection, post-acquisition corrections for defocus and optical aberrations can be performed. The introduction of the phase, though, can dramatically increase the sensitivity to motion (most prominently along the optical axis). In this paper, we present two algorithms which, together, can correct for motion in all three dimensions with enough accuracy for defocus and aberration correction in computed optical interferometric tomography. The first algorithm utilizes phase differences within the acquired data to correct for motion along the optical axis. The second algorithm utilizes the addition of a speckle tracking system using temporally- and spatially-coherent illumination to measure motion orthogonal to the optical axis. The use of coherent illumination allows for high-contrast speckle patterns even when imaging apparently uniform samples or when highly aberrated beams cannot be avoided. PMID:25574426

  12. Three-dimensional chemical profile manipulation using two-dimensional autonomous microfluidic control.

    PubMed

    Kim, Yongtae; Pekkan, Kerem; Messner, William C; Leduc, Philip R

    2010-02-03

    The ability to specify or control spatiotemporal chemical environments is critical for controlling diverse processes from chemical synthesis to cellular responses. When established by microfluidics methods, this chemical control has largely been limited to two dimensions and by the need for using complex approaches. The ability to create three-dimensional (3D) chemical patterns is becoming more critical as microfluidics is beginning to have novel applications at larger millifluidic scales, including model organism behavior, embryonic development, and optofluidics. Here, we present a simple approach to create 3D chemical patterns that can be controlled in space and time via two-dimensional (2D), single-layer fluidic modules. Not only can we employ autonomous flow in a 2D fluidic configuration to produce a 3D pattern, but with very simple changes in the 2D configuration, the chemical pattern can be "focused and defocused" within the 3D cross section. We also show that these chemical patterns can be predicted by computational fluid dynamics simulations with high experimental correlation. These simulations allow analyses of the characteristics of interface behaviors with respect to three basic yet critical parameters that need to be thoroughly considered in scaling-up from microfluidic to millifluidic research: Reynolds number (Re), inlet geometry, and channel height. The findings not only indicate proof of concept for 3D pattern creation but also reveal that a number of fluidic experiments may have inherent limitations resulting from unrecognized 3D profiles that depend on these parameter choices. These results will be useful for research areas including embryonic development, cellular stimulation, and chemical fabrication approaches.

  13. An optical profilometer for spatial characterization of three-dimensional surfaces

    NASA Technical Reports Server (NTRS)

    Kelly, W. L., IV; Burcher, E. E.; Skolaut, M. W., Jr.

    1977-01-01

    The design concept and system operation of an optical profilometer are discussed, and a preliminary evaluation of a breadboard system is presented to demonstrate the feasibility of the optical profilometer technique. Measurement results are presented for several test surfaces; and to illustrate a typical application, results are shown for a cleft palate cast used by dental surgeons. Finally, recommendations are made for future development of the optical profilometer technique for specific engineering or scientific applications.

  14. [Design of a three-dimensionally controlled multi-cell-assembly system based on the control of a mixer nozzle].

    PubMed

    Wang, Qiujun; Xu, Mingen; Li, Yanlei; Yuan, Meijuan; Hu, Jinfu

    2011-10-01

    Three-dimensionally controlled cell-assembly technique makes fabricating tissues and organs in vitro to be possible. However, for real tissues and organs with complex structure and various cells, fabricating tissues and organs in vitro need a technique that could assemble and locate multi cells and materials precisely in the space. Facing the needs of multi-cell assembly, we designed a mixer nozzle and the matching pulse switching circuit which based on the single-nozzle cell assembly system, and developed a multi-cell-assembly system. We also carried out some assembly experiments with this system using materials that were similar to the multi-component extracellular matrix materials. The results demonstrated that the system could assemble various cells and materials into three-dimensional inhomogeneous structures precisely.

  15. Three-dimensional shape measurement based on light patterns projection using diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Twardowski, P.; Serio, B.; Raulot, V.; Guilhem, M.

    2010-05-01

    We propose a structured light micro-opto electromechanical system (MOEMS) projector specially designed to display successively a set of patterns in order to extract the 3-D shape of an object using a CCD cameras module and a small ARM-based computer for control, registration and numerical analysis. This method consists in a temporal codification using a modified Gray code combined with a classical phase shifting technique. Our approach is to combine the unambiguous and robust codification of the Gray code method with the high resolution of the phase shifting method to result in highly accurate 3D reconstructions. The proposed MOEMS is based on an array of vertical-cavity surface-emitting laser (VCSEL) combined with two planar static diffractive optical elements (DOEs) arrays. DOEs masters on quartz substrate have been fabricated using photolithography therefore replication in polycarbonate is possible at low cost. The first DOE array is designed to collimate the VCSEL light (Fresnel-type element) and the second one to project the codification patterns. DOEs have been designed and fabricated by surface etching to achieve a good diffraction efficiency using four phase levels. First we introduce the MEOMS principle and the features of the different components. We present the layout design of the DOEs and describe the issues related to the micro-fabrication process. An experimental study of the topography of the DOEs is presented and discussed. We then discuss fabrication aspects including the DOEs integration and packaging.

  16. Three-dimensional Doppler, polarization-gradient, and magneto-optical forces for atoms and molecules with dark states

    NASA Astrophysics Data System (ADS)

    Devlin, J. A.; Tarbutt, M. R.

    2016-12-01

    We theoretically investigate the damping and trapping forces in a three-dimensional magneto-optical trap (MOT), by numerically solving the optical Bloch equations. We focus on the case where there are dark states because the atom is driven on a ‘type-II’ system where the angular momentum of the excited state, F\\prime , is less than or equal to that of the ground state, F. For these systems we find that the force in a three-dimensional light field has very different behaviour to its one dimensional counterpart. This differs from the more commonly used ‘type-I’ systems (F\\prime =F+1) where the 1D and 3D behaviours are similar. Unlike type-I systems where, for red-detuned light, both Doppler and sub-Doppler forces damp the atomic motion towards zero velocity, in type-II systems in 3D, the Doppler force and polarization gradient force have opposite signs. As a result, the atom is driven towards a non-zero equilibrium velocity, v 0, where the two forces cancel. We find that {v}02 scales linearly with the intensity of the light and is fairly insensitive to the detuning from resonance. We also discover a new magneto-optical force that alters the normal MOT force at low magnetic fields and whose influence is greatest in the type-II systems. We discuss the implications of these findings for the laser cooling and magneto-optical trapping of molecules where type-II transitions are unavoidable in realising closed optical cycling transitions.

  17. Optical mode confinement in three-dimensional Al/SiO2 nano-cavities with hyperbolic dispersion

    NASA Astrophysics Data System (ADS)

    Bacco, Carla; Kelly, Priscilla; Kuznetsova, Lyuba

    2015-09-01

    Today's technological needs are demanding for faster and smaller optical components. Optical microcavities offer a high confinement of electromagnetic field in a small volume, with dimensions comparable to the wavelength of light, which provides a unique system for the enhancement of light-matter interactions on the nanoscale. However, further reducing the size of the optical cavity (from microcavity to nanocavity) is limited to the fundamental diffraction limit. In hyperbolic metamaterials, large wave vectors can be achieved. Therefore, optical cavities, created from hyperbolic metamaterials, allow the confinement of the electromagnetic field to an extremely small volume with dimensions significantly smaller than the wavelength of light. This paper presents the results of numerical study of the optical mode confinement in nanocavities with hyperbolic dispersion using nanolayered Al/SiO2 hyperbolic metamaterial with different Al fill fractions. The fundamental properties of the optical modes and resonance frequencies for the nanocavities are studied using the finite-elementmethod numerical technique. Numerical simulations show that the light can be well confined in a disk with radius up to λ/65. This paper will also focus on other variables such as Q-factor and Al fill fraction. Potential future applications for three-dimensional nanocavities with hyperbolic dispersion include: silicon photonics optical communications networks, ultrafast LEDs and biological nanoparticles sensing.

  18. Hall effect control of magnetotail dawn-dusk asymmetry: A three-dimensional global hybrid simulation

    NASA Astrophysics Data System (ADS)

    Lu, San; Lin, Y.; Angelopoulos, V.; Artemyev, A. V.; Pritchett, P. L.; Lu, Quanming; Wang, X. Y.

    2016-12-01

    Magnetotail reconnection and related phenomena (e.g., flux ropes, dipolarizing flux bundles, flow bursts, and particle injections) occur more frequently on the duskside than on the dawnside. Because this asymmetry can directly result in dawn-dusk asymmetric space weather effects, uncovering its physical origin is important for better understanding, modeling, and prediction of the space weather phenomena. However, the cause of this pervasive asymmetry is unclear. Using three-dimensional global hybrid simulations, we demonstrate that the Hall physics in the magnetotail current sheet is responsible for the asymmetry. The current sheet thins progressively under enhanced global convection; when its thickness reaches ion kinetic scales, some ions are decoupled from the magnetized electrons (the Hall effect). The resultant Hall electric field Ez is directed toward the neutral plane. The Hall effect is stronger (grows faster) on the duskside; i.e., more ions become unmagnetized there and do not comove with the magnetized dawnward Ez × Bx drifting electrons, thus creating a larger additional cross-tail current intensity jy (in addition to the diamagnetic current) on the duskside, compared to the dawnside. The stronger Hall effect strength on the duskside is controlled by the higher ion temperature, thinner current sheet, and smaller normal magnetic field Bz there. These asymmetric current sheet properties are in turn controlled by two competing processes that correspond to the Hall effect: (1) the dawnward E × B drift of the magnetic flux and magnetized ions and electrons and (2) the transient motion of the unmagnetized ions which do not execute E × B drift.

  19. Three-dimensional nanometer-scale optical cavities of indefinite medium

    PubMed Central

    Yao, Jie; Yang, Xiaodong; Yin, Xiaobo; Bartal, Guy; Zhang, Xiang

    2011-01-01

    Miniaturization of optical cavities has numerous advantages for enhancing light–matter interaction in quantum optical devices, low-threshold lasers with minimal power consumption, and efficient integration of optoelectronic devices at large scale. However, the realization of a truly nanometer-scale optical cavity is hindered by the diffraction limit of the nature materials. In addition, the scaling of the photon life time with the cavity size significantly reduces the quality factor of small cavities. Here we theoretically present an approach to achieve ultrasmall optical cavities using indefinite medium with hyperbolic dispersion, which allows propagation of electromagnetic waves with wave vectors much larger than those in vacuum enabling extremely small 3D cavity down to (λ/20)3. These cavities exhibit size-independent resonance frequencies and anomalous scaling of quality factors in contrast to the conventional cavities, resulting in nanocavities with both high Q/Vm ratio and broad bandwidth. PMID:21709266

  20. Three-dimensional optical sensing network written in fused silica glass with femtosecond laser.

    PubMed

    Zhang, Haibin; Ho, Stephen; Eaton, Shane M; Li, Jianzhao; Herman, Peter R

    2008-09-01

    A single-step fast-writing method of burst ultrafast laser modification was applied to form a mesh network of multi-wavelength Bragg grating waveguides in bulk fused silica glass. Strain-optic and thermo-optic responses of the laser-written internal sensors are reported for the first time. A dual planar layout provided independent temperature- and strain-compensated characterization of temperature and strain distribution with coarse spatial resolution. The grating responses were thermally stable to 500 masculineC. To our best knowledge, the grating network represents the first demonstration of 3D distributed optical sensing network in a bulk transparent medium. Such 3D grating networks open new directions for strain and temperature sensing in optical circuits, optofluidic, MEMS or lab-on-a-chip microsystems, actuators, and windows and other large display or civil structures.

  1. Reconstruction of three-dimensional occluded object using optical flow and triangular mesh reconstruction in integral imaging.

    PubMed

    Jung, Jae-Hyun; Hong, Keehoon; Park, Gilbae; Chung, Indeok; Park, Jae-Hyeung; Lee, Byoungho

    2010-12-06

    We proposed a reconstruction method for the occluded region of three-dimensional (3D) object using the depth extraction based on the optical flow and triangular mesh reconstruction in integral imaging. The depth information of sub-images from the acquired elemental image set is extracted using the optical flow with sub-pixel accuracy, which alleviates the depth quantization problem. The extracted depth maps of sub-image array are segmented by the depth threshold from the histogram based segmentation, which is represented as the point clouds. The point clouds are projected to the viewpoint of center sub-image and reconstructed by the triangular mesh reconstruction. The experimental results support the validity of the proposed method with high accuracy of peak signal-to-noise ratio and normalized cross-correlation in 3D image recognition.

  2. Tailoring the optical property by a three-dimensional epitaxial heterostructure: a case of ZnO/SnO2.

    PubMed

    Kuang, Qin; Jiang, Zhi-Yuan; Xie, Zhao-Xiong; Lin, Shui-Chao; Lin, Zhi-Wei; Xie, Su-Yuan; Huang, Rong-Bin; Zheng, Lan-Sun

    2005-08-24

    Epitaxial growth, as a best strategy to attain a heterostructure with a well-defined and clean interface, usually takes place on a planar substrate. In this paper, using a ZnO/SnO2 core-shell heterostructure as an example, we demonstrate the possibility of establishing a three-dimensional epitaxial interface between two materials with different crystal systems for the first time and show possible tailoring optical properties by building the heteroepitaxial crystal interface. The characterization results of element mapping, high-resolution transmission electron microscopy, and selected area electric diffraction reveal that the as-prepared ZnO/SnO2 heterostructure has a tetrapod-like ZnO core and a SnO2 shell with 15-30 nm, and their special epitaxial relation is (010)SnO2//(010)ZnO and [100]SnO2//[0001]ZnO. Such three-dimensional epitaxy between the ZnO core and SnO2 shell is quite different from the usual planar epitaxy or three-dimensional epitaxy between materials having the same crystal structure. A rational model of such complicated epitaxy has been proposed through investigating the certain structural comparability between the wurtzite ZnO and rutile SnO2 crystals. The as-prepared T-ZnO/SnO2 epitaxial heterostructure exhibits unique luminescence properties in contrast with individual tetrapod ZnO and SnO2 nanostructures, in which the epitaxial interface induces new luminescence properties. This result may inspire great interest in exploring other complicated epitaxy systems and their potential applications in laser, gas sensor, solar energy conversion, photo catalysis, and nanodevices in the future.

  3. 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.

  4. Engrailed controls epaxial-hypaxial muscle innervation and the establishment of vertebrate three-dimensional mobility.

    PubMed

    Ahmed, Mohi U; Maurya, Ashish K; Cheng, Louise; Jorge, Erika C; Schubert, Frank R; Maire, Pascal; Basson, M Albert; Ingham, Philip W; Dietrich, Susanne

    2017-10-01

    Chordates are characterised by contractile muscle on either side of the body that promotes movement by side-to-side undulation. In the lineage leading to modern jawed vertebrates (crown group gnathostomes), this system was refined: body muscle became segregated into distinct dorsal (epaxial) and ventral (hypaxial) components that are separately innervated by the medial and hypaxial motors column, respectively, via the dorsal and ventral ramus of the spinal nerves. This allows full three-dimensional mobility, which in turn was a key factor in their evolutionary success. How the new gnathostome system is established during embryogenesis and how it may have evolved in the ancestors of modern vertebrates is not known. Vertebrate Engrailed genes have a peculiar expression pattern as they temporarily demarcate a central domain of the developing musculature at the epaxial-hypaxial boundary. Moreover, they are the only genes known with this particular expression pattern. The aim of this study was to investigate whether Engrailed genes control epaxial-hypaxial muscle development and innervation. Investigating chick, mouse and zebrafish as major gnathostome model organisms, we found that the Engrailed expression domain was associated with the establishment of the epaxial-hypaxial boundary of muscle in all three species. Moreover, the outgrowing epaxial and hypaxial nerves orientated themselves with respect to this Engrailed domain. In the chicken, loss and gain of Engrailed function changed epaxial-hypaxial somite patterning. Importantly, in all animals studied, loss and gain of Engrailed function severely disrupted the pathfinding of the spinal motor axons, suggesting that Engrailed plays an evolutionarily conserved role in the separate innervation of vertebrate epaxial-hypaxial muscle. Copyright © 2017. Published by Elsevier Inc.

  5. Recent progress in see-through three-dimensional displays using holographic optical elements [Invited].

    PubMed

    Jang, Changwon; Lee, Chang-Kun; Jeong, Jinsoo; Li, Gang; Lee, Seungjae; Yeom, Jiwoon; Hong, Keehoon; Lee, Byoungho

    2016-01-20

    The principles and characteristics of see-through 3D displays are presented. We especially focus on the integral-imaging display system using a holographic optical element (IDHOE), which is able to display 3D images and satisfy the see-through property at the same time. The technique has the advantage of the high transparency and capability of displaying autostereoscopic 3D images. We have analyzed optical properties of IDHOE for both recording and displaying stages. Furthermore, various studies of new applications and system improvements for IDHOE are introduced. Thanks to the characteristics of holographic volume grating, it is possible to implement a full-color lens-array holographic optical element and conjugated reconstruction as well as 2D/3D convertible IDHOE. Studies on the improvements of viewing characteristics including a viewing angle, fill factor, and resolution are also presented. Lastly, essential issues and their possible solutions are discussed as future work.

  6. In vivo label-free three-dimensional imaging of zebrafish vasculature with optical projection tomography

    NASA Astrophysics Data System (ADS)

    Bassi, Andrea; Fieramonti, Luca; D'Andrea, Cosimo; Mione, Marina; Valentini, Gianluca

    2011-10-01

    We introduce flow optical projection tomography, an imaging technique capable of visualizing the vasculature of living specimens in 3-D. The method detects the movement of cells in the bloodstream and creates flow maps using a motion-analysis procedure. Then, flow maps obtained from projection taken at several angles are used to reconstruct sections of the circulatory system of the specimen. We therefore demonstrate an in vivo, 3-D optical imaging technique that, without the use of any labeling, is able to reconstruct and visualize the vascular network of transparent and weakly scattering living specimens.

  7. Three-dimensional confinement of vapor in nanostructures for sub-Doppler optical resolution

    NASA Astrophysics Data System (ADS)

    Ballin, Philippe; Moufarej, Elias; Maurin, Isabelle; Laliotis, Athanasios; Bloch, Daniel

    2013-06-01

    We confine a Cs thermal vapor in the interstitial regions of a glass opal. We perform linear reflection spectroscopy on a cell whose window is covered with a thin film (10 or 20 layers) of ˜1000 nm (or 400 nm) diameter glass spheres and observe sub-Doppler structures in the optical spectrum for a large range of oblique incidences. This original feature associated with the inner (3-dimensional) confinement of the vapor in the interstitial regions of the opal evokes a Dicke narrowing. We finally consider possible micron-size references for optical frequency clocks based on weak, hard to saturate, molecular lines.

  8. Elevating optical activity: Efficient on-edge lithography of three-dimensional starfish metamaterial

    SciTech Connect

    Dietrich, K. Menzel, C.; Lehr, D.; Puffky, O.; Pertsch, T.; Tünnermann, A.; Kley, E.-B.; Hübner, U.

    2014-05-12

    We present an approach for extremely fast, wafer-scale fabrication of chiral starfish metamaterials based on electron beam- and on-edge lithography. A millimeter sized array of both the planar chiral and the true 3D chiral starfish is realized, and their chiroptical performances are compared by circular dichroism measurements. We find optical activity in the visible and near-infrared spectral range, where the 3D starfish clearly outperforms the planar design by almost 2 orders of magnitude, though fabrication efforts are only moderately increased. The presented approach is capable of bridging the gap between high performance optical chiral metamaterials and industrial production by nanoimprint technology.

  9. Three-dimensional quasi-conformal transformation optics through numerical optimization.

    PubMed

    Junqueira, Mateus A F C; Gabrielli, Lucas H; Beltrán-Mejía, Felipe; Spadoti, Danilo H

    2016-07-25

    In this paper we demonstrate the possibility to achieve 3-dimensional quasi-conformal transformation optics through parametrization and numerical optimization without using sliding boundary conditions. The proposed technique, which uses a quasi-Newton method, is validated in two cylindrical waveguide bends as design examples. Our results indicate an arbitrarily small average anisotropy can be achieved in 3D transformation optics as the number of degrees of freedom provided by the parametrization was increased. The waveguide simulations confirm modal preservation when the residual anisotropy is neglected.

  10. High-resolution x-ray guided three-dimensional diffuse optical tomography of joint tissues in hand osteoarthritis: Morphological and functional assessments

    PubMed Central

    Yuan, Zhen; Zhang, Qizhi; Sobel, Eric S.; Jiang, Huabei

    2010-01-01

    Purpose: The aim of this study was to investigate the potential use of multimodality functional imaging techniques to identify the quantitative optical findings that can be used to distinguish between osteoarthritic and normal finger joints. Methods: Between 2006 and 2009, the distal interphalangeal finger joints from 40 female subjects including 22 patients and 18 healthy controls were examined clinically and scanned by a hybrid imaging system. This system integrated x-ray tomosynthetic setup with a diffuse optical imaging system. Optical absorption and scattering images were recovered based on a regularization-based hybrid reconstruction algorithm. A receiver operating characteristic curve was used to calculate the statistical significance of specific optical features obtained from osteoarthritic and healthy joints groups. Results: The three-dimensional optical and x-ray images captured made it possible to quantify optical properties and joint space width of finger joints. Based on the recovered optical absorption and scattering parameters, the authors observed statistically significant differences between healthy and osteoarthritis finger joints. Conclusions: The statistical results revealed that sensitivity and specificity values up to 92% and 100%, respectively, can be achieved when optical properties of joint tissues were used as classifiers. This suggests that these optical imaging parameters are possible indicators for diagnosing osteoarthritis and monitoring its progression. PMID:20879594

  11. High-resolution x-ray guided three-dimensional diffuse optical tomography of joint tissues in hand osteoarthritis: Morphological and functional assessments

    SciTech Connect

    Yuan Zhen; Zhang Qizhi; Sobel, Eric S.; Jiang Huabei

    2010-08-15

    Purpose: The aim of this study was to investigate the potential use of multimodality functional imaging techniques to identify the quantitative optical findings that can be used to distinguish between osteoarthritic and normal finger joints. Methods: Between 2006 and 2009, the distal interphalangeal finger joints from 40 female subjects including 22 patients and 18 healthy controls were examined clinically and scanned by a hybrid imaging system. This system integrated x-ray tomosynthetic setup with a diffuse optical imaging system. Optical absorption and scattering images were recovered based on a regularization-based hybrid reconstruction algorithm. A receiver operating characteristic curve was used to calculate the statistical significance of specific optical features obtained from osteoarthritic and healthy joints groups. Results: The three-dimensional optical and x-ray images captured made it possible to quantify optical properties and joint space width of finger joints. Based on the recovered optical absorption and scattering parameters, the authors observed statistically significant differences between healthy and osteoarthritis finger joints. Conclusions: The statistical results revealed that sensitivity and specificity values up to 92% and 100%, respectively, can be achieved when optical properties of joint tissues were used as classifiers. This suggests that these optical imaging parameters are possible indicators for diagnosing osteoarthritis and monitoring its progression.

  12. Development of methods for accurate modeling of optical equipment for three-dimensional printing

    NASA Astrophysics Data System (ADS)

    Saitgalina, A. K.; Tolstoba, N. D.; Mitiushkin, A. V.

    2016-09-01

    The task of this research project is to define the extent of applicability of such 3D self-manufacture approach to the production of optical fastenings. The resulting lack of equipment, to be used for demonstration of simple experiments, which would be both competitive in performance and cheap to produce, led to the decision to research opportunities for self-manufacturing.

  13. Three-dimensional optical topography of brain activity in infants watching videos of human movement

    NASA Astrophysics Data System (ADS)

    Correia, Teresa; Lloyd-Fox, Sarah; Everdell, Nick; Blasi, Anna; Elwell, Clare; Hebden, Jeremy C.; Gibson, Adam

    2012-03-01

    We present 3D optical topography images reconstructed from data obtained previously while infants observed videos of adults making natural movements of their eyes and hands. The optical topography probe was placed over the temporal cortex, which in adults is responsible for cognitive processing of similar stimuli. Increases in oxyhaemoglobin were measured and reconstructed using a multispectral imaging algorithm with spatially variant regularization to optimize depth discrimination. The 3D optical topography images suggest that similar brain regions are activated in infants and adults. Images were presented showing the distribution of activation in a plane parallel to the surface, as well as changes in activation with depth. The time-course of activation was followed in the pixel which demonstrated the largest change, showing that changes could be measured with high temporal resolution. These results suggest that infants a few months old have regions which are specialized for reacting to human activity, and that these subtle changes can be effectively analysed using 3D optical topography.

  14. Coincident optical and thermal airborne imagery for three dimensional characterisation of forest canopies during snowmelt

    NASA Astrophysics Data System (ADS)

    Webster, Clare; Westoby, Matt; Rutter, Nick; Dunning, Stuart; Jonas, Tobias

    2017-04-01

    Remotely sensed data describing 3D forest structures are commonly retrieved using airborne or terrestrial light detection and ranging (LiDAR) methods. More recently, improvements in the affordability and accessibility of lightweight unmanned aerial system (UAS) technology has facilitated lower cost methods to obtain 2D images for input into structure from motion (SfM) models of forest canopies. Furthermore, thermal imaging technology has advanced to the stage where survey grade, portable, and easy to use cameras are readily available. The processing of 2D thermal imagery to produce complete 3D models containing thermal information has yet to be fully explored in the context of vegetation structure. We present a workflow combining airborne optical and infrared thermal imagery for generating 3D structural thermal data. Coincident optical and thermal imagery from a low-altitude UAS platform were used within SfM methods to produce 3D optical and thermal models of a standalone tree and a discontinuous forest stand. Optical and thermal point cloud densities were 35,254 and 776 points/m, compared to 78 points/m for a LiDAR dataset of the same area. Despite comparatively low resolution of thermal imagery, forest structural elements in the upper canopy can be accurately resolved.

  15. Three-dimensional optical reconstruction of vocal fold kinematics using high-speed video with a laser projection system

    PubMed Central

    Luegmair, Georg; Mehta, Daryush D.; Kobler, James B.; Döllinger, Michael

    2015-01-01

    Vocal fold kinematics and its interaction with aerodynamic characteristics play a primary role in acoustic sound production of the human voice. Investigating the temporal details of these kinematics using high-speed videoendoscopic imaging techniques has proven challenging in part due to the limitations of quantifying complex vocal fold vibratory behavior using only two spatial dimensions. Thus, we propose an optical method of reconstructing the superior vocal fold surface in three spatial dimensions using a high-speed video camera and laser projection system. Using stereo-triangulation principles, we extend the camera-laser projector method and present an efficient image processing workflow to generate the three-dimensional vocal fold surfaces during phonation captured at 4000 frames per second. Initial results are provided for airflow-driven vibration of an ex vivo vocal fold model in which at least 75% of visible laser points contributed to the reconstructed surface. The method captures the vertical motion of the vocal folds at a high accuracy to allow for the computation of three-dimensional mucosal wave features such as vibratory amplitude, velocity, and asymmetry. PMID:26087485

  16. Three-Dimensional Optical Reconstruction of Vocal Fold Kinematics Using High-Speed Video With a Laser Projection System.

    PubMed

    Luegmair, Georg; Mehta, Daryush D; Kobler, James B; Döllinger, Michael

    2015-12-01

    Vocal fold kinematics and its interaction with aerodynamic characteristics play a primary role in acoustic sound production of the human voice. Investigating the temporal details of these kinematics using high-speed videoendoscopic imaging techniques has proven challenging in part due to the limitations of quantifying complex vocal fold vibratory behavior using only two spatial dimensions. Thus, we propose an optical method of reconstructing the superior vocal fold surface in three spatial dimensions using a high-speed video camera and laser projection system. Using stereo-triangulation principles, we extend the camera-laser projector method and present an efficient image processing workflow to generate the three-dimensional vocal fold surfaces during phonation captured at 4000 frames per second. Initial results are provided for airflow-driven vibration of an ex vivo vocal fold model in which at least 75% of visible laser points contributed to the reconstructed surface. The method captures the vertical motion of the vocal folds at a high accuracy to allow for the computation of three-dimensional mucosal wave features such as vibratory amplitude, velocity, and asymmetry.

  17. Three-dimensional optical coherence micro-elastography of skeletal muscle tissue.

    PubMed

    Chin, Lixin; Kennedy, Brendan F; Kennedy, Kelsey M; Wijesinghe, Philip; Pinniger, Gavin J; Terrill, Jessica R; McLaughlin, Robert A; Sampson, David D

    2014-09-01

    In many muscle pathologies, impairment of skeletal muscle function is closely linked to changes in the mechanical properties of the muscle constituents. Optical coherence micro-elastography (OCME) uses optical coherence tomography (OCT) imaging of tissue under a quasi-static, compressive mechanical load to map variations in tissue mechanical properties on the micro-scale. We present the first study of OCME on skeletal muscle tissue. We show that this technique can resolve features of muscle tissue including fibers, fascicles and tendon, and can also detect necrotic lesions in skeletal muscle from the mdx mouse model of Duchenne muscular dystrophy. In many instances, OCME provides better or additional contrast complementary to that provided by OCT. These results suggest that OCME could provide new understanding and opportunity for assessment of skeletal muscle pathologies.

  18. Three-dimensional optical coherence micro-elastography of skeletal muscle tissue

    PubMed Central

    Chin, Lixin; Kennedy, Brendan F.; Kennedy, Kelsey M.; Wijesinghe, Philip; Pinniger, Gavin J.; Terrill, Jessica R.; McLaughlin, Robert A.; Sampson, David D.

    2014-01-01

    In many muscle pathologies, impairment of skeletal muscle function is closely linked to changes in the mechanical properties of the muscle constituents. Optical coherence micro-elastography (OCME) uses optical coherence tomography (OCT) imaging of tissue under a quasi-static, compressive mechanical load to map variations in tissue mechanical properties on the micro-scale. We present the first study of OCME on skeletal muscle tissue. We show that this technique can resolve features of muscle tissue including fibers, fascicles and tendon, and can also detect necrotic lesions in skeletal muscle from the mdx mouse model of Duchenne muscular dystrophy. In many instances, OCME provides better or additional contrast complementary to that provided by OCT. These results suggest that OCME could provide new understanding and opportunity for assessment of skeletal muscle pathologies. PMID:25401023

  19. Using nanoscale and mesoscale anisotropy to engineer the optical response of three-dimensional plasmonic metamaterials.

    PubMed

    Ross, Michael B; Blaber, Martin G; Schatz, George C

    2014-06-17

    The a priori ability to design electromagnetic wave propagation is crucial for the development of novel metamaterials. Incorporating plasmonic building blocks is of particular interest due to their ability to confine visible light. Here we explore the use of anisotropy in nanoscale and mesoscale plasmonic array architectures to produce noble metal-based metamaterials with unusual optical properties. We find that the combination of nanoscale and mesoscale anisotropy leads to rich opportunities for metamaterials throughout the visible and near-infrared. The low volume fraction (<5%) plasmonic metamaterials explored herein exhibit birefringence, a skin depth approaching that of pure metals for selected wavelengths, and directionally confined waves similar to those found in optical fibres. These data provide design principles with which the electromagnetic behaviour of plasmonic metamaterials can be tailored using high aspect ratio nanostructures that are accessible via a variety of synthesis and assembly methods.

  20. Three-dimensional line-field Fourier domain optical coherence tomography for in vivo dermatological investigation.

    PubMed

    Yasuno, Yoshiaki; Endo, Takashi; Makita, Shuichi; Aoki, Gouki; Itoh, Masahide; Yatagai, Toyohiko

    2006-01-01

    We demonstrate 3-D optical coherence tomography using only 1-D mechanical scanning. This system uses the principle of Fourier domain optical coherence tomography for depth resolution, 1-D imaging for lateral vertical resolution, and mechanical scanning by a galvanometer for lateral horizontal resolution. An in vivo human fingerpad is investigated in three dimensions with an image size of 480 points (vertical) x 300 points (horizontal) x 1024 points (depth), which corresponds to 2.1 x 1.4 x 1.3 mm. The acquisition time for a single cross section is 1 ms and that for a single volume is 10 s. The system sensitivity is 75.6 dB at a probe beam power of 1.1 mW.

  1. Evaluating a hybrid three-dimensional metrology system: merging data from optical and touch probe devices

    NASA Astrophysics Data System (ADS)

    Gerde, Janice R.; Christens-Barry, William A.

    2011-08-01

    In a project to meet requirements for CBP Laboratory analysis of footwear under the Harmonized Tariff Schedule of the United States (HTSUS), a hybrid metrology system comprising both optical and touch probe devices has been assembled. A unique requirement must be met: To identify the interface-typically obscured in samples of concern-of the "external surface area upper" (ESAU) and the sole without physically destroying the sample. The sample outer surface is determined by discrete point cloud coordinates obtained using laser scanner optical measurements. Measurements from the optically inaccessible insole region are obtained using a coordinate measuring machine (CMM). That surface similarly is defined by point cloud data. Mathematically, the individual CMM and scanner data sets are transformed into a single, common reference frame. Custom software then fits a polynomial surface to the insole data and extends it to intersect the mesh fitted to the outer surface point cloud. This line of intersection defines the required ESAU boundary, thus permitting further fractional area calculations to determine the percentage of materials present. With a draft method in place, and first-level method validation underway, we examine the transformation of the two dissimilar data sets into the single, common reference frame. We also will consider the six previously-identified potential error factors versus the method process. This paper reports our on-going work and discusses our findings to date.

  2. Three-dimensional imaging of intracochlear tissue by scanning laser optical tomography (SLOT)

    NASA Astrophysics Data System (ADS)

    Tinne, N.; Nolte, L.; Antonopoulos, G. C.; Schulze, J.; Andrade, J.; Heisterkamp, A.; Meyer, H.; Warnecke, A.; Majdani, O.; Ripken, T.

    2016-02-01

    The presented study focuses on the application of scanning laser optical tomography (SLOT) for non-destructive visualization of anatomical structures inside the human cochlea ex vivo. SLOT is a laser-based highly efficient microscopy technique, which allows for tomographic imaging of the internal structure of transparent large-scale specimens (up to 1 cm3). Thus, in the field of otology this technique is best convenient for an ex vivo study of the inner ear anatomy. For this purpose, the preparation before imaging comprises mechanically assisted decalcification, dehydration as well as optical clearing of the cochlea samples. Here, we demonstrate results of SLOT visualizing hard and soft tissue structures of the human cochlea with an optical resolution in the micrometer range using absorption and autofluorescence as contrast mechanisms. Furthermore, we compare our results with the method of X-ray micro tomography (micro-CT, μCT) as clinical gold standard which is based only on absorption. In general, SLOT can provide the advantage of covering all contrast mechanisms known from other light microscopy techniques, such as fluorescence or scattering. For this reason, a protocol for antibody staining has been developed, which additionally enables selective mapping of cellular structures within the cochlea. Thus, we present results of SLOT imaging rodent cochleae showing specific anatomical structures such as hair cells and neurofilament via fluorescence. In conclusion, the presented study has shown that SLOT is an ideally suited tool in the field of otology for in toto visualization of the inner ear microstructure.

  3. Three-dimensional fluorescence-enhanced optical tomography using a hand-held probe based imaging system

    PubMed Central

    Ge, Jiajia; Zhu, Banghe; Regalado, Steven; Godavarty, Anuradha

    2008-01-01

    Hand-held based optical imaging systems are a recent development towards diagnostic imaging of breast cancer. To date, all the hand-held based optical imagers are used to perform only surface mapping and target localization, but are not capable of demonstrating tomographic imaging. Herein, a novel hand-held probe based optical imager is developed towards three-dimensional (3-D) optical tomography studies. The unique features of this optical imager, which primarily consists of a hand-held probe and an intensified charge coupled device detector, are its ability to; (i) image large tissue areas (5×10 sq. cm) in a single scan, (ii) perform simultaneous multiple point illumination and collection, thus reducing the overall imaging time; and (iii) adapt to varying tissue curvatures, from a flexible probe head design. Experimental studies are performed in the frequency domain on large slab phantoms (∼650 ml) using fluorescence target(s) under perfect uptake (1:0) contrast ratios, and varying target depths (1–2 cm) and X-Y locations. The effect of implementing simultaneous over sequential multiple point illumination towards 3-D tomography is experimentally demonstrated. The feasibility of 3-D optical tomography studies has been demonstrated for the first time using a hand-held based optical imager. Preliminary fluorescence-enhanced optical tomography studies are able to reconstruct 0.45 ml target(s) located at different target depths (1–2 cm). However, the depth recovery was limited as the actual target depth increased, since only reflectance measurements were acquired. Extensive tomography studies are currently carried out to determine the resolution and performance limits of the imager on flat and curved phantoms. PMID:18697559

  4. Photorefractive Three-Dimensional Disks for Optical Data Storage and Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Li, Hsin-Yu Sidney

    This thesis is on the application of 3-D photorefractive crystals disks for holographic optical data storage and optical neural networks. Chapter 1 gives some introductory background and motivation for the materials given in this thesis. In Chapter 2, the coupled-mode analysis and Born's approximation in anisotropic crystals is reviewed. The results are similar to that of isotropic materials. However, there are approximations that are often neglected in the literature. Chapter 3 starts with the description of the holographic 3-D disk for data storage, and analyzes the various alignment errors and tolerance problems for a 3-D disk system. Of particular interest is the effects in image reconstruction caused by rotational angle error. An optimum configuration is found that minimizes this error. Chapter 4 examines the data storage density of 3-D disks and volume holographic storage systems that utilize wavelength/angle and spatial multiplexing. The maximum storage density and the geometry that achieves this density is derived. Chapter 5 discusses the diffraction efficiency of 3-D disks fabricated with photorefractive crystals. Practical geometries and crystal orientations for achieving maximum uniform diffraction efficiency are given and compared to the maximum obtainable diffraction efficiencies using arbitrary cut crystals. Experimental results are shown. Also derived in this chapter are the double grating effect from crystal anisotropy, and the optimum configuration for getting maximum diffraction efficiency using the 90 degree recording geometry. The Khuktarev band-transport model of the photorefractive effect is examined briefly with emphasis on the anisotropy of the material. The proper expression for the permittivity term in the space-charge field formula is derived. Chapter 6 gives an example of an optical neural network that uses photorefractive crystals. It is the real time face-recognition system. The setup and experiments are described. Some properties of

  5. Three-dimensional choroidal segmentation in spectral OCT volumes using optic disc prior information

    NASA Astrophysics Data System (ADS)

    Hu, Zhihong; Girkin, Christopher A.; Hariri, Amirhossein; Sadda, SriniVas R.

    2016-03-01

    Recently, much attention has been focused on determining the role of the peripapillary choroid - the layer between the outer retinal pigment epithelium (RPE)/Bruchs membrane (BM) and choroid-sclera (C-S) junction, whether primary or secondary in the pathogenesis of glaucoma. However, the automated choroidal segmentation in spectral-domain optical coherence tomography (SD-OCT) images of optic nerve head (ONH) has not been reported probably due to the fact that the presence of the BM opening (BMO, corresponding to the optic disc) can deflect the choroidal segmentation from its correct position. The purpose of this study is to develop a 3D graph-based approach to identify the 3D choroidal layer in ONH-centered SD-OCT images using the BMO prior information. More specifically, an initial 3D choroidal segmentation was first performed using the 3D graph search algorithm. Note that varying surface interaction constraints based on the choroidal morphological model were applied. To assist the choroidal segmentation, two other surfaces of internal limiting membrane and innerouter segment junction were also segmented. Based on the segmented layer between the RPE/BM and C-S junction, a 2D projection map was created. The BMO in the projection map was detected by a 2D graph search. The pre-defined BMO information was then incorporated into the surface interaction constraints of the 3D graph search to obtain more accurate choroidal segmentation. Twenty SD-OCT images from 20 healthy subjects were used. The mean differences of the choroidal borders between the algorithm and manual segmentation were at a sub-voxel level, indicating a high level segmentation accuracy.

  6. Optical and transport properties in three-dimensional Dirac and Weyl semimetals

    NASA Astrophysics Data System (ADS)

    Tabert, C. J.; Carbotte, J. P.; Nicol, E. J.

    2016-02-01

    Within a Kubo formalism, we study dc transport and ac optical properties of 3D Dirac and Weyl semimetals. Emphasis is placed on the approach to charge neutrality and on the differences between Dirac and Weyl materials. At charge neutrality, the zero-temperature limit of the dc conductivity is not universal and also depends on the residual scattering model employed. However, the Lorenz number L retains its usual value L0. With increasing temperature, the Wiedemann-Franz law is violated. At high temperatures, L exhibits a new plateau at a value dependent on the details of the scattering rate. Such details can also appear in the optical conductivity, both in the Drude response and interband background. In the clean limit, the interband background is linear in photon energy and always extrapolates to the origin. This background can be shifted to the right through the introduction of a massless gap. In this case, the extrapolation can cut the axis at a finite photon energy as is observed in some experiments. It is also of interest to differentiate between the two types of Weyl semimetals: those with broken time-reversal symmetry and those with broken spatial-inversion symmetry. We show that, while the former will follow the same behavior as the 3D Dirac semimetals, for the zero magnetic field properties discussed here, the latter type will show a double step in the optical conductivity at finite doping and a single absorption edge at charge neutrality. The Drude conductivity is always finite in this case, even at charge neutrality.

  7. Three-dimensional optical imaging of microvascular networks within intact lymph node in vivo

    NASA Astrophysics Data System (ADS)

    Jung, Yeongri; Zhi, Zhongwei; Wang, Ruikang K.

    2010-09-01

    Sentinel lymph nodes (SLNs) are the first lymph nodes to drain wastes originated from cancerous tissue. There is a need for an in vivo imaging method that can image the intact SLN to further our understanding of its normal as well as abnormal functions. We report the use of ultrahigh sensitive optical microangiography (UHS-OMAG) to image functional microvascular and lymphatic vessel networks that innervate the intact lymph node in mice in vivo. The promising results show a potential role of UHS-OMAG in the future understanding and diagnosis of the SLN involvement in cancer development.

  8. The Three-Dimensional Ray Trajectories of the WKB Optical Fiber Modes

    DTIC Science & Technology

    1993-03-01

    source-free, homogeneous media , we have [Vt+k 2(r)]E=0, (2-1) where k(r) is the wave number and E is the electric field. It is noted that this equation...homogeneous media , we have optical fibers, the approximate Eikonal ray approach [21, which in turn is based on Fermat’s [V+k2()=E-l) extremum...that (r, 0, z) locate the ray , For purposes of analysis the geometrica relationships are more carefully defined in the nex’ Figure 31: Geometry of the

  9. Optical scanning holography as a technique for high-resolution three-dimensional biological microscopy

    NASA Astrophysics Data System (ADS)

    Swoger, Jim; Martinez-Corral, Manuel; Huisken, Jan; Stelzer, Ernst H. K.

    2002-09-01

    The applicability of optical scanning holography (OSH) to the field of microscopic imaging for biological applications is assessed. A generalized mathematical description of OSH that takes into account polarization effects, high numerical apertures, and generalized illumination wave fronts is presented. This description is used to show that the proposed single-beam scanning technique relaxes the restrictions under which OSH functions correctly compared with the conventional double-beam scanning method. It is also shown that, although in general OSH is restricted to thin samples, this condition can be relaxed in nonrefracting fluorescence samples, which are of importance in biological microscopy.

  10. Visualizing biofilm formation in endotracheal tubes using endoscopic three-dimensional optical coherence tomography

    PubMed Central

    Heidari, Andrew E.; Moghaddam, Samer; Truong, Kimberly K.; Chou, Lidek; Genberg, Carl; Brenner, Matthew; Chen, Zhongping

    2015-01-01

    Abstract. Biofilm formation has been linked to ventilator-associated pneumonia, which is a prevalent infection in hospital intensive care units. Currently, there is no rapid diagnostic tool to assess the degree of biofilm formation or cellular biofilm composition. Optical coherence tomography (OCT) is a minimally invasive, nonionizing imaging modality that can be used to provide high-resolution cross-sectional images. Biofilm deposited in critical care patients’ endotracheal tubes was analyzed in vitro. This study demonstrates that OCT could potentially be used as a diagnostic tool to analyze and assess the degree of biofilm formation and extent of airway obstruction caused by biofilm in endotracheal tubes. PMID:26720877

  11. Image aberrations in optical three-dimensional measurement systems with fringe projection.

    PubMed

    Brakhage, Peter; Notni, Gunther; Kowarschik, Richard

    2004-06-01

    In optical shape measurement systems, systematic errors appear as a result of imaging aberrations of the lens assemblies in the cameras and projectors. A mathematical description of this effect is intended to correct the whole measurement area with a few independent coefficients. We apply the ideas of photogrammetry to one- and two-dimensional fringe projection techniques. We also introduce some new terms for close-range applications and telecentric objectives. Further, an algorithm for distance-dependent corrections is introduced. Also, we describe a new method with which to determine coefficients of aberration with an optimization-based method.

  12. Optical authentication method using a three-dimensional phase object with various wavelength readouts.

    PubMed

    Matoba, Osamu; Sawasaki, Tomo; Nitta, Kouichi

    2008-08-20

    An optical system for authentication using a 3D (3D) random phase object with various wavelength readouts is proposed. The 3D phase object without surface modulation is secure when the scattering is strong enough because it prevents from the interferometric measurement. The identification is implemented by the correlation between a measured speckle pattern of the 3D phase object and stored speckle patterns. For accurate identification, two speckle patterns of the 3D object obtained by illuminating two wavelengths are used. Experimental demonstrations and numerical evaluations of wavelength selectivity are presented.

  13. Three-dimensional movement analysis for near infrared system using stereo vision and optical flow techniques

    NASA Astrophysics Data System (ADS)

    Parra Escamilla, Geliztle A.; Serrano Garcia, David I.; Otani, Yukitoshi

    2017-04-01

    The purpose of this paper is the measurement of spatial-temporal movements by using stereo vision and 3D optical flow algorithms applied at biological samples. Stereo calibration procedures and algorithms for enhance the contrast intensity were applied. The system was implemented for working at the first near infrared windows (NIR-I) at 850 nm due of the penetration depth obtained at this region in biological tissue. Experimental results of 3D tracking of human veins are presented showing the characteristics of the implementation.

  14. Three-dimensional imaging of micro-specimen by optical scanning holography

    NASA Astrophysics Data System (ADS)

    Liu, Jung-Ping; Tsou, Cheng-Hao

    2017-04-01

    Optical scanning holography (OSH) is a scanning-type digital holographic technique. In OSH, a heterodyne interference pattern is generated to raster scan the object. OSH can be operated in the incoherent mode and thus is able to record a fluorescence hologram. In addition, resolution of the OSH is proportional to the density of the interference pattern. Here we use a high-NA microscope objective to generate a dynamic Fresnel zone plate to record a hologram of micro-specimen. The achieved transverse resolution and longitudinal resolution are 0.78μm and 3.1μm, respectively.

  15. Comparison of two and three-dimensional optical tomographic image reconstructions of human finger joints.

    PubMed

    Song, Rong; Klose, Alexander D; Scheel, Alexander K; Netz, Uwe; Beuthan, Jurgen; Hielscher, Andreas H

    2006-01-01

    We have developed an images reconstruction algorithm to recover spatial distribution of optical properties in human finger joints for early diagnosis and monitoring of rheumatoid arthritis (RA). An optimization method iteratively employs a light propagation and scattering coefficients distribution for near-infrared (NIR) light inside the joint tissue. We developed the differences in cross-sectional images obtained by using the reconstruction algorithms with 2-dimensional and 3-dimensional light propagation models. In particular we examined how these different approaches affect the discrimination between healthy and RA joints.

  16. Visualizing biofilm formation in endotracheal tubes using endoscopic three-dimensional optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Heidari, Andrew E.; Moghaddam, Samer; Troung, Kimberly K.; Chou, Lidek; Genberg, Carl; Brenner, Matthew; Chen, Zhongping

    2015-12-01

    Biofilm formation has been linked to ventilator-associated pneumonia, which is a prevalent infection in hospital intensive care units. Currently, there is no rapid diagnostic tool to assess the degree of biofilm formation or cellular biofilm composition. Optical coherence tomography (OCT) is a minimally invasive, nonionizing imaging modality that can be used to provide high-resolution cross-sectional images. Biofilm deposited in critical care patients' endotracheal tubes was analyzed in vitro. This study demonstrates that OCT could potentially be used as a diagnostic tool to analyze and assess the degree of biofilm formation and extent of airway obstruction caused by biofilm in endotracheal tubes.

  17. Visualizing dynamics of angiogenic sprouting from a three-dimensional microvasculature model using stage-top optical coherence tomography

    PubMed Central

    Takahashi, Haruko; Kato, Keisuke; Ueyama, Kenji; Kobayashi, Masayoshi; Baik, Gunwoong; Yukawa, Yasuhiro; Suehiro, Jun-ichi; Matsunaga, Yukiko T.

    2017-01-01

    Three-dimensional (3D) in vitro microvasculature in a polydimethylsiloxane-based microdevice was developed as a physiologically relevant model of angiogenesis. The angiogenic process is monitored using stage-top optical coherence tomography (OCT). OCT allows non-invasive monitoring of the 3D structures of the prepared host microvasculature and sprouted neovasculature without fluorescence staining. OCT monitoring takes only a few minutes to scan through the several-millimetre scale range, which provides the advantage of rapid observation of living samples. The obtained OCT cross-sectional images capture 3D features of the angiogenic sprouting process and provide information on the dynamics of luminal formation. The stage-top system used in this study enables the observer to visualize the in vitro dynamics of 3D cultured cells simply and conveniently, offering an alternative monitoring method for studies on angiogenesis and providing quantitative information about vascular morphological changes. PMID:28186184

  18. Visualizing dynamics of angiogenic sprouting from a three-dimensional microvasculature model using stage-top optical coherence tomography.

    PubMed

    Takahashi, Haruko; Kato, Keisuke; Ueyama, Kenji; Kobayashi, Masayoshi; Baik, Gunwoong; Yukawa, Yasuhiro; Suehiro, Jun-Ichi; Matsunaga, Yukiko T

    2017-02-10

    Three-dimensional (3D) in vitro microvasculature in a polydimethylsiloxane-based microdevice was developed as a physiologically relevant model of angiogenesis. The angiogenic process is monitored using stage-top optical coherence tomography (OCT). OCT allows non-invasive monitoring of the 3D structures of the prepared host microvasculature and sprouted neovasculature without fluorescence staining. OCT monitoring takes only a few minutes to scan through the several-millimetre scale range, which provides the advantage of rapid observation of living samples. The obtained OCT cross-sectional images capture 3D features of the angiogenic sprouting process and provide information on the dynamics of luminal formation. The stage-top system used in this study enables the observer to visualize the in vitro dynamics of 3D cultured cells simply and conveniently, offering an alternative monitoring method for studies on angiogenesis and providing quantitative information about vascular morphological changes.

  19. Segmentation of nucleus and cytoplasm of a single cell in three-dimensional tomogram using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Chang, Chia-Kai; Tsai, Chien-Chung; Hsu, Wan-Yi; Chen, Jau-Shiuh; Liao, Yi-Hua; Sheen, Yi-Shuan; Hong, Jin-Bon; Lin, Ming-Yi; Tjiu, Jeng-Wei; Huang, Sheng-Lung

    2017-03-01

    A random rayburst sampling (RRBS) framework was developed to detect the nucleus and cell membrane boundaries in three-dimensional (3-D) space. Raw images were acquired through a full-field optical coherence tomography system with submicron resolution-i.e., 0.8 μm in lateral and 0.9 μm in axial directions. The near-isometric resolution enables 3-D segmentation of a nucleus and cell membrane for determining the volumetric nuclear-to-cytoplasmic (N/C) ratio of a single cell. The RRBS framework was insensitive to the selection of seeds and image pixel noise. The robustness of the RRBS framework was verified through the convergence of the N/C ratio searching algorithm. The relative standard deviation of the N/C ratio between different randomly selected seed sets was only 2%. This technique is useful for various in vitro assays on single-cell analyses.

  20. Gold coated optical fibers as three-dimensional electrodes for microfluidic enzymatic biofuel cells: Toward geometrically enhanced performance

    PubMed Central

    Desmaële, Denis; Renaud, Louis; Tingry, Sophie

    2015-01-01

    For the first time, we report on the preliminary evaluation of gold coated optical fibers (GCOFs) as three-dimensional (3D) electrodes for a membraneless glucose/O2 enzymatic biofuel cell. Two off-the-shelf 125 μm diameter GCOFs were integrated into a 3D microfluidic chip fabricated via rapid prototyping. Using soluble enzymes and a 10 mM glucose solution flowing at an average velocity of 16 mm s−1 along 3 mm long GCOFs, the maximum power density reached 30.0 ± 0.1 μW cm−2 at a current density of 160.6 ± 0.3 μA cm−2. Bundles composed of multiple GCOFs could further enhance these first results while serving as substrates for enzyme immobilization. PMID:26339305

  1. Three-dimensional segmentation and reconstruction of the retinal vasculature from spectral-domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Guimarães, Pedro; Rodrigues, Pedro; Celorico, Dirce; Serranho, Pedro; Bernardes, Rui

    2015-01-01

    We reconstruct the three-dimensional shape and location of the retinal vascular network from commercial spectral-domain (SD) optical coherence tomography (OCT) data. The two-dimensional location of retinal vascular network on the eye fundus is obtained through support vector machines classification of properly defined fundus images from OCT data, taking advantage of the fact that on standard SD-OCT, the incident light beam is absorbed by hemoglobin, creating a shadow on the OCT signal below each perfused vessel. The depth-wise location of the vessel is obtained as the beginning of the shadow. The classification of crossovers and bifurcations within the vascular network is also addressed. We illustrate the feasibility of the method in terms of vessel caliber estimation and the accuracy of bifurcations and crossovers classification.

  2. Segmentation of nucleus and cytoplasm of a single cell in three-dimensional tomogram using optical coherence tomography.

    PubMed

    Chang, Chia-Kai; Tsai, Chien-Chung; Hsu, Wan-Yi; Chen, Jau-Shiuh; Liao, Yi-Hua; Sheen, Yi-Shuan; Hong, Jin-Bon; Lin, Ming-Yi; Tjiu, Jeng-Wei; Huang, Sheng-Lung

    2017-03-01

    A random rayburst sampling (RRBS) framework was developed to detect the nucleus and cell membrane boundaries in three-dimensional (3-D) space. Raw images were acquired through a full-field optical coherence tomography system with submicron resolution—i.e., 0.8 ?? ? m in lateral and 0.9 ?? ? m in axial directions. The near-isometric resolution enables 3-D segmentation of a nucleus and cell membrane for determining the volumetric nuclear-to-cytoplasmic (N/C) ratio of a single cell. The RRBS framework was insensitive to the selection of seeds and image pixel noise. The robustness of the RRBS framework was verified through the convergence of the N/C ratio searching algorithm. The relative standard deviation of the N/C ratio between different randomly selected seed sets was only 2%. This technique is useful for various in vitro assays on single-cell analyses.

  3. Quantifying three-dimensional rodent retina vascular development using optical tissue clearing and light-sheet microscopy

    NASA Astrophysics Data System (ADS)

    Singh, Jasmine N.; Nowlin, Taylor M.; Seedorf, Gregory J.; Abman, Steven H.; Shepherd, Douglas P.

    2017-07-01

    Retinal vasculature develops in a highly orchestrated three-dimensional (3-D) sequence. The stages of retinal vascularization are highly susceptible to oxygen perturbations. We demonstrate that optical tissue clearing of intact rat retinas and light-sheet microscopy provides rapid 3-D characterization of vascular complexity during retinal development. Compared with flat mount preparations that dissect the retina and primarily image the outermost vascular layers, intact cleared retinas imaged using light-sheet fluorescence microscopy display changes in the 3-D retinal vasculature rapidly without the need for point scanning techniques. Using a severe model of retinal vascular disruption, we demonstrate that a simple metric based on Sholl analysis captures the vascular changes observed during retinal development in 3-D. Taken together, these results provide a methodology for rapidly quantifying the 3-D development of the entire rodent retinal vasculature.

  4. Automated three-dimensional registration and volume rebuilding for wide-field angiographic and structural optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Zang, Pengxiao; Liu, Gangjun; Zhang, Miao; Wang, Jie; Hwang, Thomas S.; Wilson, David J.; Huang, David; Li, Dengwang; Jia, Yali

    2017-02-01

    We propose a three-dimensional (3-D) registration method to correct motion artifacts and construct the volume structure for angiographic and structural optical coherence tomography (OCT). This algorithm is particularly suitable for the nonorthogonal wide-field OCT scan acquired by a ultrahigh-speed swept-source system (>200 kHz A-scan rate). First, the transverse motion artifacts are corrected by the between-frame registration based on en face OCT angiography (OCTA). After A-scan transverse translation between B-frames, the axial motions are corrected based on the rebuilt boundary of inner limiting membrane. Finally, a within-frame registration is performed for local optimization based on cross-sectional OCTA. We evaluated this algorithm on retinal volumes of six normal subjects. The results showed significantly improved retinal smoothness in 3-D-registered structural OCT and image contrast on en face OCTA.

  5. Three-dimensional optical coherence tomography of the embryonic murine cardiovascular system

    NASA Astrophysics Data System (ADS)

    Luo, Wei; Marks, Daniel L.; Ralston, Tyler S.; Boppart, Stephen A.

    2006-03-01

    Optical coherence tomography (OCT) is an emerging high-resolution real-time biomedical imaging technology that has potential as a novel investigational tool in developmental biology and functional genomics. In this study, murine embryos and embryonic hearts are visualized with an OCT system capable of 2-µm axial and 15-µm lateral resolution and with real-time acquisition rates. We present, to our knowledge, the first sets of high-resolution 2- and 3-D OCT images that reveal the internal structures of the mammalian (murine) embryo (E10.5) and embryonic (E14.5 and E17.5) cardiovascular system. Strong correlations are observed between OCT images and corresponding hematoxylin- and eosin-stained histological sections. Real-time in vivo embryonic (E10.5) heart activity is captured by spectral-domain optical coherence tomography, processed, and displayed at a continuous rate of five frames per second. With the ability to obtain not only high-resolution anatomical data but also functional information during cardiovascular development, the OCT technology has the potential to visualize and quantify changes in murine development and in congenital and induced heart disease, as well as enable a wide range of basic in vitro and in vivo research studies in functional genomics.

  6. Method for the three-dimensional localization of intramyocardial excitation centers using optical imaging.

    PubMed

    Khait, Vadim D; Bernus, Olivier; Mironov, Sergey F; Pertsov, Arkady M

    2006-01-01

    This study explores the possibility of localizing the excitation centers of electrical waves inside the heart wall using voltage-sensitive dyes (fluorescent or absorptive). In the present study, we propose a method for the 3-D localization of excitation centers from pairs of 2-D images obtained in two modes of observation: reflection and transillumination. Such images can be obtained using high-speed charge-coupled device (CCD) cameras and photodiode arrays with time resolution up to 0.5 ms. To test the method, we simulate optical signals produced by point sources and propagating ellipsoidal waves in 1-cm-thick slabs of myocardial tissue. Solutions of the optical diffusion equation are constructed by employing the method of images with Robin boundary conditions. The coordinates of point sources as well as of the centers of expanding waves can be accurately determined using the proposed algorithm. The method can be extended to depth estimations of the outer boundaries of the expanding wave. The depth estimates are based on ratios of spatially integrated images. The method shows high tolerance to noise and can give accurate results even at relatively low signal-to-noise ratios. In conclusion, we propose a novel and efficient algorithm for the localization of excitation centers in 3-D cardiac tissue.

  7. Three-dimensional optical tomographic brain imaging during kainic-acid-induced seizures in rats

    NASA Astrophysics Data System (ADS)

    Bluestone, Avraham Y.; Sakamoto, Kenichi; Hielscher, Andreas H.; Stewart, Mark

    2005-04-01

    In this study, we explored the potential of diffuse optical tomography for brain oximetry and describe our efforts towards imaging hemodynamic changes in rat brains during kainic-acid (KA) induced seizures. Using electrophysiological techniques we first showed that KA induces a pronounced transient hypotension in urethane anesthetized rats that is coincident with seizure activity beginning in ventral and spreading to dorsal hippocampus. We observed sustained increases in vagus and sympathetic activity during generalized limbic seizure activity, which alters blood pressure regulation and heart rhythms. Subsequently, we used optical tomographic methods to study KA induced seizures in anesthetized animals to better define the hemodynamic cerebral vascular response. We observed a lateralized increase in deoxyhemoglobin after KA injection at the time when the blood pressure (BP) was decreased. By contrast, injection of phenylephrine produced a symmetric global increase in total hemoglobin. These findings indicate that our instrument is sensitive to the local hemodynamics, both in response to a global increase in blood pressure (phenylephrine injection) and a lateralized decrease in oxyhemoglobin produced by an asymmetric response to KA; a response that may be critically important for severe autonomic nervous system alterations during seizures. The results of this study provide the impetus for combining complimentary modalities, imaging and electrophysiological, to ultimately gain a better understanding of the underlying physiology of seizure activity in the rat.

  8. Multispectral in vivo three-dimensional optical coherence tomography of human skin

    NASA Astrophysics Data System (ADS)

    Alex, Aneesh; Považay, Boris; Hofer, Bernd; Popov, Sergei; Glittenberg, Carl; Binder, Susanne; Drexler, Wolfgang

    2010-03-01

    The capability of optical coherence tomography (OCT) to perform ``optical biopsy'' of tissues within a depth range of 1 to 2 mm with micron-scale resolution in real time makes it a promising biomedical imaging modality for dermatologic applications. Three high-speed, spectrometer-based frequency-domain OCT systems operating at 800 nm (20,000 A-scans/s), 1060 nm, and 1300 nm (both 47,000 A-scans/s) at comparable signal-to-noise ratio (SNR), SNR roll-off with scanning depth, and transverse resolution (<15 μm) were used to acquire 3-D tomograms of glabrous and hairy human skin in vivo. Images obtained using these three systems were compared in terms of penetration depth, resolution, and contrast. Normal as well as abnormal sites like moles and scar tissue were examined. In this preliminary study, skin pigmentation had little effect on penetration accomplished at three different wavelengths. The epidermis and dermal-epidermal junction could be properly delineated using OCT at 800 nm, and this wavelength offered better contrast over the other two wavelength regions. OCT at 1300 nm permits imaging of deeper dermal layers, critical for detecting deeper tumor boundaries and other deeper skin pathologies. The performance at 1060 nm compromises between the other wavelengths in terms of penetration depth and image contrast.

  9. Chaos and band structure in a three-dimensional optical lattice.

    PubMed

    Boretz, Yingyue; Reichl, L E

    2015-04-01

    Classical chaos is known to affect wave propagation because it signifies the presence of broken symmetries. The effect of chaos has been observed experimentally for matter waves, electromagnetic waves, and acoustic waves. When these three types of waves propagate through a spatially periodic medium, the allowed propagation energies form bands. For energies in the band gaps, no wave propagation is possible. We show that optical lattices provide a well-defined system that allows a study of the effect of chaos on band structure. We have determined the band structure of a body-centered-cubic optical lattice for all theoretically possible couplings, and we find that the band structure for those lattices realizable in the laboratory differs significantly from that expected for the bands in an "empty" body-centered-cubic crystal. However, as coupling is increased, the lattice becomes increasingly chaotic and it becomes possible to produce band structure that has behavior qualitatively similar to the "empty" body-centered-cubic band structure, although with fewer degeneracies.

  10. Development of a three-dimensional correction method for optical distortion of flow field inside a liquid droplet.

    PubMed

    Gim, Yeonghyeon; Ko, Han Seo

    2016-04-15

    In this Letter, a three-dimensional (3D) optical correction method, which was verified by simulation, was developed to reconstruct droplet-based flow fields. In the simulation, a synthetic phantom was reconstructed using a simultaneous multiplicative algebraic reconstruction technique with three detectors positioned at the synthetic object (represented by the phantom), with offset angles of 30° relative to each other. Additionally, a projection matrix was developed using the ray tracing method. If the phantom is in liquid, the image of the phantom can be distorted since the light passes through a convex liquid-vapor interface. Because of the optical distortion effect, the projection matrix used to reconstruct a 3D field should be supplemented by the revision ray, instead of the original projection ray. The revision ray can be obtained from the refraction ray occurring on the surface of the liquid. As a result, the error on the reconstruction field of the phantom could be reduced using the developed optical correction method. In addition, the developed optical method was applied to a Taylor cone which was caused by the high voltage between the droplet and the substrate.

  11. Bragg Gratings in Polarization Maintaining Optical Fiber as Three Dimensional Strain Sensor

    NASA Astrophysics Data System (ADS)

    Quintana, Joel

    Fiber-Bragg Gratings (FBG) for Structural Health Monitoring (SHM) have been studied extensively as they offer electrically passive operation, electromagnetic interference (EMI) immunity, high sensitivity and multiplexing as compared to conventional electric strain sensors. FBG sensors written within polarization maintaining (PM) optical fiber offer additional dimensions of strain measurement, greatly reducing the number of sensors needed to properly monitor a structure. This reduction however, adds complexity to the dis- crimination of the sensor's optical response to its corresponding applied strains. This dissertation defines the set of algorithms needed to measure planar strain using PM-FBGs exclusively. It defines the minimum number of sensors needed to reconstruct the full state of strain, epsilon and the maximum number of strain tensor components a single PM-FBG is capable of measuring. Two experiments were performed under the same test specifications; a single PM-FBG and 2 multiplexed PM-FBGs in a rosette pattern adhered to a test spec- imen subject to uniaxial tension. The far field strain was measured at the location of the sensor using only the optical response and PM-FBG axes orientation with respect to the specimen axes. Strains at the surface of the specimen were measured using Digital Image Correlation (DIC) analysis and an electronic extensometer. The PM-FBG measurements where then compared to the DIC/extensometer data for validation. The comparison of the strains epsilonxx, epsilon yy, and epsilonxy resulted in a high correlation, averaging .97 between the strain mea- surement techniques. The PM-FBG measured specimen surface strains with low percent error values (approximately 20%). PM-FBG sensitivity is greatly affected by the sensor's material properties and installation or embedding techniques. The algorithm for measuring a full state of planar strain at a point presented in this dissertation and is validated though experimental analysis. It can

  12. Low temperature hermetically sealed three-dimensional MEMS device for wireless optical communication

    NASA Astrophysics Data System (ADS)

    Agarwal, Rahul

    Novel processes were developed that resulted in a self-packaged device during the system integration, along with a transparent lid for inspection or optical probing. A new process was developed for improving the verticality in Micro Electro Mechanical Systems (MEMS) structures using Deep Reactive Ion Etching (DRIE). A self-pattered, mask-less photolithography technique was developed to metallize these vertical structures while maintaining a transparent window, for packaging of various MEMS devices. The verticality and metallization coverage were evaluated by incorporating the MEMS structures into an optical Corner Cube Retroreflector (CCR). A low temperature, hermetic sealing technique was also developed using In-Au thermo-compression bonding at 160°C. Cross-shaped 550microm deep vertical mirrors, with sidewall angles of 90.08° were etched with this new DRIE technique. This is the best reported sidewall angle for such deep structures. The typical scalloped DRIE sidewall roughness was reduced to 40nm using wet polishing. A bonded Pyrex wafer was used as the handle wafer during DRIE; it eventually forms the package window after DRIE. The metallized, vertical mirrors were bonded to a MEMS device chip to assemble and package the CCR. The MEMS device chip consisted of an array of torsion mirrors. The mirrors were designed to modulate at 6Vp-p--20V p-p, with the resonant frequencies ranging from 25 KHz--50 KHz. The design and simulation results are presented. To test the hermetic seal, helium leak tests were performed on the packaged device. Leak rates of as low as 2.8x10-8atm cc/s air were detected, which is better than the MIL-STD-883G of 5x10-8 atm cc/s air for a package volume of 7.8x10-3 CC. A microprocessor and temperature/humidity sensor was then integrated with the CCR to assemble a passive optical digital data communicator. A flexible circuit design and a folded packaging scheme were utilized to minimize the overall form factor. Flat, flexible polymer

  13. Arithmetic of focused vortex beams in three-dimensional optical lattice arrays.

    PubMed

    Davis, Jeffrey A; Cottrell, Don M; McCormick, Kyle R; Albero, Jorge; Moreno, Ignacio

    2014-04-01

    In this work, we present a method to generate a 3D lattice of vortex beams. We apply phase look-up tables (LUTs) designed to generate gratings having an arbitrary content of diffraction orders. This phase LUT can be applied to a variety of diffraction optical elements, such as linear phase gratings, blazed diffractive lenses, and spiral phase patterns. We concentrate on combinations of all of these to create 3D structures of vortex beams. In particular, we generate all of these elements in the first output quadrant and eliminate the zero-order diffraction that often unavoidably accompanies these patterns. We discuss different ways of producing these 3D vortex gratings, and how the various output beams are related to the arithmetic of the 3D distribution of topological charges. Experimental results are provided by means of a liquid crystal spatial light modulator.

  14. Three-dimensional OCT based guinea pig eye model: relating morphology and optics

    PubMed Central

    Pérez-merino, Pablo; Velasco-Ocana, Miriam; Martinez-Enriquez, Eduardo; Revuelta, Luis; McFadden, Sally A; Marcos, Susana

    2017-01-01

    Custom Spectral Optical Coherence Tomography (SOCT) provided with automatic quantification and distortion correction algorithms was used to measure the 3-D morphology in guinea pig eyes (n = 8, 30 days; n = 5, 40 days). Animals were measured awake in vivo under cyclopegia. Measurements showed low intraocular variability (<4% in corneal and anterior lens radii and <8% in the posterior lens radii, <1% interocular distances). The repeatability of the surface elevation was less than 2 µm. Surface astigmatism was the individual dominant term in all surfaces. Higher-order RMS surface elevation was largest in the posterior lens. Individual surface elevation Zernike terms correlated significantly across corneal and anterior lens surfaces. Higher-order-aberrations (except spherical aberration) were comparable with those predicted by OCT-based eye models. PMID:28736663

  15. Three-dimensional OCT based guinea pig eye model: relating morphology and optics.

    PubMed

    Pérez-Merino, Pablo; Velasco-Ocana, Miriam; Martinez-Enriquez, Eduardo; Revuelta, Luis; McFadden, Sally A; Marcos, Susana

    2017-04-01

    Custom Spectral Optical Coherence Tomography (SOCT) provided with automatic quantification and distortion correction algorithms was used to measure the 3-D morphology in guinea pig eyes (n = 8, 30 days; n = 5, 40 days). Animals were measured awake in vivo under cyclopegia. Measurements showed low intraocular variability (<4% in corneal and anterior lens radii and <8% in the posterior lens radii, <1% interocular distances). The repeatability of the surface elevation was less than 2 µm. Surface astigmatism was the individual dominant term in all surfaces. Higher-order RMS surface elevation was largest in the posterior lens. Individual surface elevation Zernike terms correlated significantly across corneal and anterior lens surfaces. Higher-order-aberrations (except spherical aberration) were comparable with those predicted by OCT-based eye models.

  16. Optical coherence tomography of cell dynamics in three-dimensional engineered tissues

    NASA Astrophysics Data System (ADS)

    Tan, Wei; Desai, Tejal A.; Leckband, Deborah; Boppart, Stephen A.

    2005-03-01

    Cell-based engineered tissue models have been increasingly useful in the field of tissue engineering, in in vitro drug screening systems, and in complex cell biology studies. While techniques for engineering tissue models have advanced, there have been few imaging technique capable of assessing the complex 3-D cell behaviors in real-time and at the depths that comprise thick tissues. Understanding cell behavior requires advanced imaging tools to progress from characterizing 2-D cell cultures to complex, highly-scattering, thick 3-D tissue constructs. Optical coherence tomography (OCT) is an emerging biomedical imaging technique that can perform cellular-resolution imaging in situ and in real-time. OCT, which uses near-infrared laser light, provides deep-tissue imaging up to several millimeters within highly-scattering tissue, thus permitting visualization of changes at depths previously unattainable. In this study, we demonstrate that it is possible to use OCT to evaluate dynamic cell behavior and function in a quantitative fashion in four dimensions (3-D space plus time). We investigated and characterized cell dynamics and processes in deep tissue models, such as cell de-adhesion, cell proliferation, cell chemotaxis migration, cell necrosis, and cell apoptosis. This optical imaging technique was developed and utilized in order to gain new insights into how chemical microenvironments influence cellular functions and dynamics in multi-dimensional models. In addition, by detecting the changes in cell dynamics, effective chemical concentration could be estimated. With high penetration depth and increased spatial and temporal resolution in 3-D space, OCT will be a useful tool for improving our understanding of cell dynamics in situ and in real-time, for elucidating the complex biological interactions, and for directing our designs toward functional and biomimetic engineered tissues.

  17. Demonstration of a Controllable Three-Dimensional Brownian Motor in Symmetric Potentials

    SciTech Connect

    Sjoelund, P.; Petra, S.J.H.; Dion, C.M.; Jonsell, S.; Nylen, M.; Kastberg, A.; Sanchez-Palencia, L.

    2006-05-19

    We demonstrate a Brownian motor, based on cold atoms in optical lattices, where isotropic random fluctuations are rectified in order to induce controlled atomic motion in arbitrary directions. In contrast to earlier demonstrations of ratchet effects, our Brownian motor operates in potentials that are spatially and temporally symmetric, but where spatiotemporal symmetry is broken by a phase shift between the potentials and asymmetric transfer rates between them. The Brownian motor is demonstrated in three dimensions and the noise-induced drift is controllable in our system.

  18. The interaction of Escherichia coli with its surrounding three dimensional substrate measured by oscillatory optical tweezers

    NASA Astrophysics Data System (ADS)

    Yen, Pei-Wen; Su, Pin-Tzu; Hung, Li-Jen; Wei, Ming-Tzo; Syu, Wan-Jr; Chiou, Arthur

    2009-08-01

    It has been known that the shape, the locomotion, and the growth of cells and bacteria are often affected by their interactions with extra cellular matrix (ECM). However, it is difficult to quantify such interactions with conventional biochemical methods. In this paper we report the application of oscillatory optical tweezers to trap and oscillate three types of E. coli, in 0.2% LB agar substrate to quantify the E. coli - substrate interactions in terms of the elasticity modulus G'. The three types of E. coli are BW25113 (wild-type, normal with flagellum), BW25113 (normal with flagellum, but subjected to UV light exposure for 1 hr to deactivate the flagellum), and JW1923 (a null-flagellum mutant of BW25113). Our results indicate that the value of G' for the later two is significantly higher than that for the normal wild-type (WT). We speculated that the interaction with the surrounding is perturbed, and hence reduced, mainly by the motion of the flagellum in the case of the WT.

  19. Three-dimensional photonic crystal fluorinated tin oxide (FTO) electrodes : synthesis and optical and electrical properties.

    SciTech Connect

    Yang, Z.; Gao, S.; Li, W.; Vlasko-Vlasov, V.; Welp, U.; Kwok, W.-K.; Xu, T.

    2011-04-01

    Photovoltaic (PV) schemes often encounter a pair of fundamentally opposing requirements on the thickness of semiconductor layer: a thicker PV semiconductor layer provides enhanced optical density, but inevitably increases the charge transport path length. An effective approach to solve this dilemma is to enhance the interface area between the terminal electrode, i.e., transparent conducting oxide (TCO) and the semiconductor layer. As such, we report a facile, template-assisted, and solution chemistry-based synthesis of 3-dimensional inverse opal fluorinated tin oxide (IO-FTO) electrodes. Synergistically, the photonic crystal structure possessed in the IO-FTO exhibits strong light trapping capability. Furthermore, the electrical properties of the IO-FTO electrodes are studied by Hall effect and sheet resistance measurement. Using atomic layer deposition method, an ultrathin TiO{sub 2} layer is coated on all surfaces of the IO-FTO electrodes. Cyclic voltammetry study indicates that the resulting TiO{sub 2}-coated IO-FTO shows excellent potentials as electrodes for electrolyte-based photoelectrochemical solar cells.

  20. Three Dimensional Motion Tracking for High Resolution Optical Microscopy, in vivo

    PubMed Central

    Pursley, Randall; Pohida, Thomas J.; Glancy, Brian; Taylor, Joni; Chess, David; Kellman, Peter; Xue, Hui; Balaban, Robert S.

    2013-01-01

    When conducting optical imaging experiments, in vivo, the signal to noise ratio and effective spatial and temporal resolution is fundamentally limited by physiological motion of the tissue. A 3-dimensional motion tracking scheme, using a multi-photon excitation microscope with a resonant galvanometer, (512×512 pixels at 33 frames/sec) is described to overcome physiological motion, in vivo. The use of commercially available graphical processing units permitted the rapid 3-dimensional cross-correlation of sequential volumes to detect displacements and adjust tissue position to track motions in near real-time. Motion phantom tests maintained micron resolution with displacement velocities of up to 200 μm/min, well within the drift observed in many biological tissues under physiologically relevant conditions. In vivo experiments on mouse skeletal muscle using the capillary vasculature with luminal dye as a displacement reference revealed an effective and robust method of tracking tissue motion to enable (1) signal averaging over time without compromising resolution, and (2) tracking of cellular regions during a physiological perturbation. PMID:22582797

  1. Analyzing three-dimensional ultrastructure of human cervical tissue using optical coherence tomography.

    PubMed

    Gan, Yu; Yao, Wang; Myers, Kristin M; Vink, Joy Y; Wapner, Ronald J; Hendon, Christine P

    2015-04-01

    During pregnancy, the uterine cervix is the mechanical barrier that prevents delivery of a fetus. The underlying cervical collagen ultrastructure, which influences the overall mechanical properties of the cervix, plays a role in maintaining a successful pregnancy until term. Yet, not much is known about this collagen ultrastructure in pregnant and nonpregnant human tissue. We used optical coherence tomography to investigate the directionality and dispersion of collagen fiber bundles in the human cervix. An image analysis tool has been developed, combining a stitching method with a fiber orientation measurement, to study axially sliced cervix samples. This tool was used to analyze the ultrastructure of ex-vivo pregnant and non-pregnant hysterectomy tissue samples taken at the internal os, which is the region of the cervix adjacent to the uterus. With this tool, directionality maps of collagen fiber bundles and dispersion of collagen fiber orientation were analyzed. It was found that that the overall preferred directionality of the collagen fibers for both the nonpregnant and pregnant samples were circling around the inner cervical canal. Pregnant samples showed greater dispersion than non-pregnant samples. Lastly, we observed regional differences in collagen fiber dispersion. Fibers closer to the inner canal showed more dispersion than the fibers on the radial edges.

  2. High-Speed GPU-Based Fully Three-Dimensional Diffuse Optical Tomographic System.

    PubMed

    Saikia, Manob Jyoti; Kanhirodan, Rajan; Mohan Vasu, Ram

    2014-01-01

    We have developed a graphics processor unit (GPU-) based high-speed fully 3D system for diffuse optical tomography (DOT). The reduction in execution time of 3D DOT algorithm, a severely ill-posed problem, is made possible through the use of (1) an algorithmic improvement that uses Broyden approach for updating the Jacobian matrix and thereby updating the parameter matrix and (2) the multinode multithreaded GPU and CUDA (Compute Unified Device Architecture) software architecture. Two different GPU implementations of DOT programs are developed in this study: (1) conventional C language program augmented by GPU CUDA and CULA routines (C GPU), (2) MATLAB program supported by MATLAB parallel computing toolkit for GPU (MATLAB GPU). The computation time of the algorithm on host CPU and the GPU system is presented for C and Matlab implementations. The forward computation uses finite element method (FEM) and the problem domain is discretized into 14610, 30823, and 66514 tetrahedral elements. The reconstruction time, so achieved for one iteration of the DOT reconstruction for 14610 elements, is 0.52 seconds for a C based GPU program for 2-plane measurements. The corresponding MATLAB based GPU program took 0.86 seconds. The maximum number of reconstructed frames so achieved is 2 frames per second.

  3. High-Speed GPU-Based Fully Three-Dimensional Diffuse Optical Tomographic System

    PubMed Central

    Saikia, Manob Jyoti; Kanhirodan, Rajan; Mohan Vasu, Ram

    2014-01-01

    We have developed a graphics processor unit (GPU-) based high-speed fully 3D system for diffuse optical tomography (DOT). The reduction in execution time of 3D DOT algorithm, a severely ill-posed problem, is made possible through the use of (1) an algorithmic improvement that uses Broyden approach for updating the Jacobian matrix and thereby updating the parameter matrix and (2) the multinode multithreaded GPU and CUDA (Compute Unified Device Architecture) software architecture. Two different GPU implementations of DOT programs are developed in this study: (1) conventional C language program augmented by GPU CUDA and CULA routines (C GPU), (2) MATLAB program supported by MATLAB parallel computing toolkit for GPU (MATLAB GPU). The computation time of the algorithm on host CPU and the GPU system is presented for C and Matlab implementations. The forward computation uses finite element method (FEM) and the problem domain is discretized into 14610, 30823, and 66514 tetrahedral elements. The reconstruction time, so achieved for one iteration of the DOT reconstruction for 14610 elements, is 0.52 seconds for a C based GPU program for 2-plane measurements. The corresponding MATLAB based GPU program took 0.86 seconds. The maximum number of reconstructed frames so achieved is 2 frames per second. PMID:24891848

  4. Reliability and validity of measurements of facial swelling with a stereophotogrammetry optical three-dimensional scanner.

    PubMed

    van der Meer, Wicher J; Dijkstra, Pieter U; Visser, Anita; Vissink, Arjan; Ren, Yijin

    2014-12-01

    Volume changes in facial morphology can be assessed using the 3dMD DSP400 stereo-optical 3-dimensional scanner, which uses visible light and has a short scanning time. Its reliability and validity have not to our knowledge been investigated for the assessment of facial swelling. Our aim therefore was to assess them for measuring changes in facial contour, in vivo and in vitro. Twenty-four healthy volunteers with and without an artificial swelling of the cheek were scanned, twice in the morning and twice in the afternoon (in vivo measurements). A mannequin head was scanned 4 times with and without various externally applied artificial swellings (in vitro measurements). The changes in facial contour caused by the artificial swelling were measured as the change in volume of the cheek (with and without artificial swelling in place) using 3dMD Vultus software. In vivo and in vitro reliability expressed in intraclass correlations were 0.89 and 0.99, respectively. In vivo and in vitro repeatability coefficients were 5.9 and 1.3 ml, respectively. The scanner underestimated the volume by 1.2 ml (95% CI -0.9 to 3.4) in vivo and 0.2 ml (95% CI 0.02 to 0.4) in vitro. The 3dMD stereophotogrammetry scanner is a valid and reliable tool to measure volumetric changes in facial contour of more than 5.9 ml and for the assessment of facial swelling.

  5. Quantitative Evaluation of the Natural Progression of Keratoconus Using Three-Dimensional Optical Coherence Tomography.

    PubMed

    Fujimoto, Hisataka; Maeda, Naoyuki; Shintani, Ayumi; Nakagawa, Tomoya; Fuchihata, Mutsumi; Higashiura, Ritsuko; Nishida, Kohji

    2016-07-01

    We quantified the chronologic progression of keratoconus using anterior segment optical coherence tomography (AS-OCT). A total of 217 eyes from 113 patients with keratoconus, keratoconus suspect, or forme fruste keratoconus were evaluated by corneal tomography using swept-source OCT. Age-dependent changes in the radius of the posterior best-fit sphere (Rpost), minimum corneal thickness (Tmin), and distance from the thinnest point to the corneal vertex (Dmin) were examined over follow-up periods of up to 5.79 years and were analyzed using generalized estimating equation (GEE) nonlinear regression model. Annual changes in Rpost (mean, -0.017 mm) and Tmin (-2.69 μm) were significantly higher in younger patients (P < 0.01, GEE nonlinear regression) and in patients with higher maximal K value (Kmax; P < 0.01, GEE nonlinear regression), whereas no changes were observed in Dmin. Even in patients 30 years or older, 14% of eyes revealed remarkable progression in Rpost. In eyes with acute hydrops, annual changes in Rpost (-0.22 mm) and Tmin (-33.8 μm) before acute corneal hydrops were more than 10 times faster than those in other eyes (P < 0.001, GEE nonlinear regression). Chronologic measurements of corneal tomography in keratoconus demonstrated that the progression of steepening at posterior corneal surface was found not only in patients under 30 years but also in older patients, particularly in advanced keratoconus. The rate of progression can be measured by mapping of corneal curvature and thickness using OCT, and the risk of progression was greater in younger patients with steeper Kmax.

  6. Three-Dimensional Analysis of Enamel Crack Behavior Using Optical Coherence Tomography.

    PubMed

    Segarra, M S; Shimada, Y; Sadr, A; Sumi, Y; Tagami, J

    2017-03-01

    The aim of this study was to nondestructively analyze enamel crack behavior on different areas of teeth using 3D swept source-optical coherence tomography (SS-OCT). Ten freshly extracted human teeth of each type on each arch ( n = 80 teeth) were inspected for enamel crack patterns on functional, contact and nonfunctional, or noncontact areas using 3D SS-OCT. The predominant crack pattern for each location on each specimen was noted and analyzed. The OCT observations were validated by direct observations of sectioned specimens under confocal laser scanning microscopy (CLSM). Cracks appeared as bright lines with SS-OCT, with 3 crack patterns identified: Type I - superficial horizontal cracks; Type II - vertically (occluso-gingival) oriented cracks; and Type III - hybrid or complicated cracks, a combination of a Type I and Type III cracks, which may or may not be confluent with each other. Type II cracks were predominant on noncontacting surfaces of incisors and canines and nonfunctional cusps of posterior teeth. Type I and III cracks were predominant on the contacting surfaces of incisors, cusps of canines, and functional cusps of posterior teeth. Cracks originating from the dental-enamel junction and enamel tufts, crack deflections, and the initiation of new cracks within the enamel (internal cracks) were observed as bright areas. CLSM observations corroborated the SS-OCT findings. We found that crack pattern, tooth type, and the location of the crack on the tooth exhibited a strong correlation. We show that the use of 3D SS-OCT permits for the nondestructive 3D imaging and analysis of enamel crack behavior in whole human teeth in vitro. 3D SS-OCT possesses potential for use in clinical studies for the analysis of enamel crack behavior.

  7. Three dimensional data-driven multi scale atomic representation of optical coherence tomography.

    PubMed

    Kafieh, Raheleh; Rabbani, Hossein; Selesnick, Ivan

    2015-05-01

    In this paper, we discuss about applications of different methods for decomposing a signal over elementary waveforms chosen in a family called a dictionary (atomic representations) in optical coherence tomography (OCT). If the representation is learned from the data, a nonparametric dictionary is defined with three fundamental properties of being data-driven, applicability on 3D, and working in multi-scale, which make it appropriate for processing of OCT images. We discuss about application of such representations including complex wavelet based K-SVD, and diffusion wavelets on OCT data. We introduce complex wavelet based K-SVD to take advantage of adaptability in dictionary learning methods to improve the performance of simple dual tree complex wavelets in speckle reduction of OCT datasets in 2D and 3D. The algorithm is evaluated on 144 randomly selected slices from twelve 3D OCTs taken by Topcon 3D OCT-1000 and Cirrus Zeiss Meditec. Improvement of contrast to noise ratio (CNR) (from 0.9 to 11.91 and from 3.09 to 88.9, respectively) is achieved. Furthermore, two approaches are proposed for image segmentation using diffusion. The first method is designing a competition between extended basis functions at each level and the second approach is defining a new distance for each level and clustering based on such distances. A combined algorithm, based on these two methods is then proposed for segmentation of retinal OCTs, which is able to localize 12 boundaries with unsigned border positioning error of 9.22 ±3.05 μm, on a test set of 20 slices selected from 13 3D OCTs.

  8. Three-dimensional fluorescence tomography of human breast tissues in vivo using a hand-held optical imager

    PubMed Central

    Erickson, Sarah J; Martinez, Sergio L; DeCerce, Joseph; Romero, Adrian; Caldera, Lizeth; Godavarty, Anuradha

    2013-01-01

    Diffuse optical imaging using non-ionizing radiation is a non-invasive method that shows promise towards breast cancer diagnosis. Hand-held optical imagers show potential for clinical translation of the technology, yet they have not been used towards 3D tomography. Herein, 3D tomography of human breast tissue in vivo is demonstrated for the first time using a hand-held optical imager with automated coregistration facilities. Simulation studies are performed on breast geometries to demonstrate the feasibility of 3D tomographic imaging using a hand-held imager under perfect (1:0) and imperfect (100:1, 50:1) fluorescence absorption contrast ratios. Experimental studies are performed in vivo using a 1 μM ICG filled phantom target placed non-invasively underneath the flap of the breast tissue. Results show the ability to perform automated tracking and coregistered imaging of human breast tissue (with tracking accuracy on the order of ~1 cm). Three-dimensional tomography results demonstrated the ability to recover a single target placed at a depth of 2.5 cm, from both the simulated (at 1:0, 100:1 and 50:1 contrasts) and experimental cases on actual breast tissues. Ongoing efforts to improve target depth recovery are carried out via implementation of transmittance imaging in the hand-held imager. PMID:23417060

  9. Fast computation of Fresnel diffraction field of a three-dimensional object for a pixelated optical device.

    PubMed

    Esmer, G Bora

    2013-01-01

    In this paper, a fast algorithm is proposed for accurate calculation of the scalar optical diffraction on a pixelated optical device used in the reconstruction process from a three-dimensional object that is formed by scattered sample points over the space. In computer-generated holography, fast and accurate calculation of the diffraction field is an important and a challenging problem. Therefore, several fast algorithms can be found in the literature. The accuracy of the calculations can be determined by the signal processing techniques and the numerical methods used in the calculation of diffraction fields. Furthermore, the quality of reconstructed objects can be affected by the properties of optical devices employed in the reconstruction process. For instance, the pixelated structure of those devices has a significant effect on the reconstruction process. Therefore, the pixelated structure of the display device has to be taken into account. Furthermore, fast calculation of the diffraction pattern can be a bottleneck in dynamic holographic content generation. As a solution to the problems, we propose a fast and accurate algorithm based on a precomputed one-dimensional kernel and scaling of that kernel for the computation of the diffraction pattern for a pixelated display.

  10. Synchronous triple-optical-path digital speckle pattern interferometry with fast discrete curvelet transform for measuring three-dimensional displacements

    NASA Astrophysics Data System (ADS)

    Gu, Guoqing; Wang, Kaifu; Wang, Yanfang; She, Bin

    2016-06-01

    Digital speckle pattern interferometry (DSPI) is a well-established and widely used optical measurement technique for obtaining qualitative as well as quantitative measurements of objects deformation. The simultaneous measurement of an object's surface displacements in three dimensions using DSPI is of great interest. This paper presents a triple-optical-path DSPI based method for the simultaneous and independent measurement of three-dimensional (3D) displacement fields. In the proposed method, in-plane speckle interferometers with dual-observation geometry and an out-of-plane interferometer are optimally combined to construct an integrated triple-optical-path DSPI system employing the phase shift technique, which uses only a single laser source and three cameras. These cameras are placed along a single line to synchronously capture real-time visible speckle fringe patterns in three dimensions. In addition, a pre-filtering method based on the fast discrete curvelet transform (FDCT) is utilized for denoising the obtained wrapped phase patterns to improve measurement accuracy. Finally, the simultaneous measurement of the 3D displacement fields of a simple beam and a composite laminated plate respectively subjected to three-point and single-point bend loading are investigated to validate the feasibility and effectiveness of the proposed method.

  11. Fast segmentation and high-quality three-dimensional volume mesh creation from medical images for diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Jermyn, Michael; Ghadyani, Hamid; Mastanduno, Michael A.; Turner, Wes; Davis, Scott C.; Dehghani, Hamid; Pogue, Brian W.

    2013-08-01

    Multimodal approaches that combine near-infrared (NIR) and conventional imaging modalities have been shown to improve optical parameter estimation dramatically and thus represent a prevailing trend in NIR imaging. These approaches typically involve applying anatomical templates from magnetic resonance imaging/computed tomography/ultrasound images to guide the recovery of optical parameters. However, merging these data sets using current technology requires multiple software packages, substantial expertise, significant time-commitment, and often results in unacceptably poor mesh quality for optical image reconstruction, a reality that represents a significant roadblock for translational research of multimodal NIR imaging. This work addresses these challenges directly by introducing automated digital imaging and communications in medicine image stack segmentation and a new one-click three-dimensional mesh generator optimized for multimodal NIR imaging, and combining these capabilities into a single software package (available for free download) with a streamlined workflow. Image processing time and mesh quality benchmarks were examined for four common multimodal NIR use-cases (breast, brain, pancreas, and small animal) and were compared to a commercial image processing package. Applying these tools resulted in a fivefold decrease in image processing time and 62% improvement in minimum mesh quality, in the absence of extra mesh postprocessing. These capabilities represent a significant step toward enabling translational multimodal NIR research for both expert and nonexpert users in an open-source platform.

  12. Three-dimensional defocused orientation sensing of single bimetallic core-shell gold nanorods as multifunctional optical probes.

    PubMed

    Kim, Geun Wan; Lee, So Young; Ha, Ji Won

    2017-03-13

    Bimetallic core-shell gold nanorods (AuNRs) are promising multifunctional orientation probes that can be employed in biological and physical studies. This paper presents the optical properties of single AuNRs coated with palladium (Pd) and platinum (Pt) under scattering-based dark-field (DF) microscopy. Strong longitudinal plasmon damping was observed for the bimetallic AuNRs due to Pd and Pt metals on the AuNR surface. Despite the strong plasmon damping, the bimetallic AuNRs yielded characteristic doughnut-shaped scattering patterns under defocused DF microscopy. Interestingly, a solid bright spot appeared at the center of the defocused scattering patterns due to strong damping in the longitudinal plasmon and the increased contribution from the transverse dipoles to the image patterns, which was verified further by a simulation study. Furthermore, the defocused scattering field distributions enabled a determination of the three-dimensional (3D) orientations of single bimetallic AuNRs through a pattern-match analysis technique without angular degeneracy. Therefore, deeper insight into the optical properties and defocused scattering patterns of single bimetallic AuNRs is provided, which can be used to develop multifunctional optical probes that are capable of sensing of the 3D orientation of a probe, biomolecules based on LSPR shift, gas and humidity, etc.

  13. Monitoring the response to primary medical therapy for breast cancer using three- dimensional time-resolved optical mammography.

    PubMed

    Enfield, L C; Cantanhede, G; Westbroek, D; Douek, M; Purushotham, A D; Hebden, J C; Gibson, A P

    2011-12-01

    Primary medical therapy is used to reduce tumour size prior to surgery in women with locally advanced breast cancer. Optical tomography is a functional imaging technique using near- infrared light to produce three-dimensional breast images of tissue oxygen saturation and haemoglobin concentration. Its advantages include the ability to display quantitative physiological information, and to allow repeated scans without the hazards associated with exposure to ionising radiation. There is a need for a non-invasive functional imaging tool to evaluate response to treatment, so that non-responders can be given the opportunity to change their treatment regimen. Here, we evaluate the use of optical tomography for this purpose. Four women with newly diagnosed breast cancer who were about to undergo primary medical therapy gave informed and voluntary consent to take part in the study. Changes in physiological and optical properties within the tumour were evaluated during the course of neoadjuvant chemotherapy. Optical imaging was performed prior to treatment, after the first cycle of chemotherapy, halfway through, and on completion of chemotherapy. Images of light absorption and scatter at two wavelengths were produced, from which images of total haemoglobin concentration and oxygen saturation were derived. All patients that showed a good or complete response to treatment on MRI showed a corresponding recovery in the haemoglobin concentration images. Changes in mean tumour total haemoglobin concentration could be seen four weeks into treatment. The tumour oxygen saturation was low compared to background in three out of four patients, and also showed a return to baseline over treatment. Optical imaging of the breast is feasible during primary medical therapy and can be used to assess response to treatment over six months.

  14. Quadcopter control in three-dimensional space using a noninvasive motor imagery based brain-computer interface

    PubMed Central

    LaFleur, Karl; Cassady, Kaitlin; Doud, Alexander; Shades, Kaleb; Rogin, Eitan; He, Bin

    2013-01-01

    Objective At the balanced intersection of human and machine adaptation is found the optimally functioning brain-computer interface (BCI). In this study, we report a novel experiment of BCI controlling a robotic quadcopter in three-dimensional physical space using noninvasive scalp EEG in human subjects. We then quantify the performance of this system using metrics suitable for asynchronous BCI. Lastly, we examine the impact that operation of a real world device has on subjects’ control with comparison to a two-dimensional virtual cursor task. Approach Five human subjects were trained to modulate their sensorimotor rhythms to control an AR Drone navigating a three-dimensional physical space. Visual feedback was provided via a forward facing camera on the hull of the drone. Individual subjects were able to accurately acquire up to 90.5% of all valid targets presented while travelling at an average straight-line speed of 0.69 m/s. Significance Freely exploring and interacting with the world around us is a crucial element of autonomy that is lost in the context of neurodegenerative disease. Brain-computer interfaces are systems that aim to restore or enhance a user’s ability to interact with the environment via a computer and through the use of only thought. We demonstrate for the first time the ability to control a flying robot in the three-dimensional physical space using noninvasive scalp recorded EEG in humans. Our work indicates the potential of noninvasive EEG based BCI systems to accomplish complex control in three-dimensional physical space. The present study may serve as a framework for the investigation of multidimensional non-invasive brain-computer interface control in a physical environment using telepresence robotics. PMID:23735712

  15. Three-Dimensional Proton Beam Writing of Optically Active Coherent Vacancy Spins in Silicon Carbide.

    PubMed

    Kraus, H; Simin, D; Kasper, C; Suda, Y; Kawabata, S; Kada, W; Honda, T; Hijikata, Y; Ohshima, T; Dyakonov, V; Astakhov, G V

    2017-05-10

    Constructing quantum devices comprises various challenging tasks, especially when concerning their nanoscale geometry. For quantum color centers, the traditional approach is to fabricate the device structure after the nondeterministic placement of the centers. Reversing this approach, we present the controlled generation of quantum centers in silicon carbide (SiC) by focused proton beam in a noncomplex manner without need for pre- or postirradiation treatment. The generation depth and resolution can be predicted by matching the proton energy to the material's stopping power, and the amount of quantum centers at one specific sample volume is tunable from ensembles of millions to discernible single photon emitters. We identify the generated centers as silicon vacancies through their characteristic magnetic resonance signatures and demonstrate that they possess a long spin-echo coherence time of 42 ± 20 μs at room temperature. Our approach hence enables the fabrication of quantum hybrid nanodevices based on SiC platform, where spin centers are integrated into p-i-n diodes, photonic cavities, and mechanical resonators.

  16. Comparison of the three-dimensional correctness of impression techniques: a randomized controlled trial.

    PubMed

    Luthardt, Ralph Gunnar; Walter, Michael H; Quaas, Sebastian; Koch, Rainer; Rudolph, Heike

    2010-01-01

    In vitro studies showed superior impression correctness for one-stage impressions. However, clinical data, especially clinical trials, are lacking in this matter. The aim of the study was to investigate the three-dimensional correctness of impressions for final restorations applying three different impression techniques. Three impressions each were made from 48 patients with different techniques using metal stock trays. In a randomized order, one-stage putty-wash, two-stage putty-wash, and monophase impressions (respectively, Dimension Penta H and Garant L, Dimension Penta H Quick and Garant L Quick, Impregum Penta; 3M ESPE) were made with either polyvinyl siloxane or polyether materials. The double-cord technique was applied at all abutment teeth. Factors potentially influencing the correctness of the impressions were recorded. The precision of the impressions was three-dimensionally analyzed using the resulting gypsum models. Discrepancies between the impressions were calculated using the one-stage putty-wash impression as reference. Discrepancies between the one-stage putty-wash impressions and the monophase impressions are significantly lower compared with two-stage putty-wash impressions. The depth of the most subgingival portion of the preparation margin significantly influences the discrepancies between the impression techniques. In light of the major influence of clinical parameters on impression correctness, one-stage procedures should be favored. These findings support the results of in vitro investigations.

  17. Three-dimensional visualization of choroidal vessels by using standard and ultra-high resolution scattering optical coherence angiography

    NASA Astrophysics Data System (ADS)

    Hong, Youngjoo; Makita, Shuich; Yamanari, Masahiro; Miura, Masahiro; Kim, Soohyun; Yatagai, Toyohiko; Yasuno, Yoshiaki

    2007-06-01

    Scattering optical coherence angiography (S-OCA) is a noninvasive imaging method that is based on the high-speed standard 800nm band spectral-domain optical coherence tomography (SD-OCT) and the ultra-high-resolution SD-OCT which has the axial resolution of 6.1 μm and 2.9 μm in tissue, respectively. In this paper, we have demonstrated the use of this method for in vivo human retinal imaging. A three-dimensional view of the choroidal vasculature was obtained by segmenting the choroidal vessels; this was done using intensity threshold based binarization at each depth plane relative to the retinal pigment epithelium. A vascular projection image was obtained by integrating the segmented choroidal vasculature. In order to assess the feasibility of the proposed method, we compared these images with those obtained using existing invasive methods such as fluorescein angiography and indocyanine green angiography. Clinically worthful images are obtained from the application of S-OCA to the agerelated macular degeneration and polypoidal choroidal vasculopathy.

  18. Three-dimensional reconstruction of flame temperature and emissivity distribution using optical tomographic and two-colour pyrometric techniques

    NASA Astrophysics Data System (ADS)

    Moinul Hossain, Md; Lu, Gang; Sun, Duo; Yan, Yong

    2013-07-01

    This paper presents an experimental investigation, visualization and validation in the three-dimensional (3D) reconstruction of flame temperature and emissivity distributions by using optical tomographic and two-colour pyrometric techniques. A multi-camera digital imaging system comprising eight optical imaging fibres and two RGB charged-couple device (CCD) cameras are used to acquire two-dimensional (2D) images of the flame simultaneously from eight equiangular directions. A combined logical filtered back-projection (LFBP) and simultaneous iterative reconstruction and algebraic reconstruction technique (SART) algorithm is utilized to reconstruct the grey-level intensity of the flame for the two primary colour (red and green) images. The temperature distribution of the flame is then determined from the ratio of the reconstructed grey-level intensities and the emissivity is estimated from the ratio of the grey level of a primary colour image to that of a blackbody source at the same temperature. The temperature measurement of the system was calibrated using a blackbody furnace as a standard temperature source. Experimental work was undertaken to validate the flame temperature obtained by the imaging system against that obtained using high-precision thermocouples. The difference between the two measurements is found no greater than ±9%. Experimental results obtained on a laboratory-scale propane fired combustion test rig demonstrate that the imaging system and applied technical approach perform well in the reconstruction of the 3D temperature and emissivity distributions of the sooty flame.

  19. Study of laser carving three-dimensional structures on ceramics: Quality controlling and mechanisms

    NASA Astrophysics Data System (ADS)

    Wang, Cheng; Zeng, Xiaoyan

    2007-10-01

    Three-dimensional (3D) laser carving is a new, very flexible process and is very useful for machining the hard and/or brittle materials such as ceramics, carbide and hardened steel with high precision, excellent productivity and surface quality. In this paper, the effects of laser processing parameters on single-layer carving depth and surface quality are analyzed by laser carving on an Al 2O 3 ceramic with different processing parameters. The mechanisms of laser carving are also studied. A mathematical model of the relationship between the laser processing parameters and the laser carving depth is established, which is useful in obtaining the best machining parameters with the shortest time. Finally, a 3D pattern is successfully carved using the optimum parameters.

  20. Control of three-dimensional cell adhesion by the chirality of nanofibers in hydrogels.

    PubMed

    Liu, Guo-Feng; Zhang, Di; Feng, Chuan-Liang

    2014-07-21

    In the three-dimensional (3D) extracellular matrix (ECM), the influence of nanofiber chirality on cell behavior is very important; the helical nanofibrous structure is closely related to the relevant biological events. Herein, we describe the use of the two enantiomers of a 1,4-benzenedicarboxamide phenylalanine derivative as supramolecular gelators to investigate the influence of the chirality of nanofibers on cell adhesion and proliferation in three dimensions. It was found that left-handed helical nanofibers can increase cell adhesion and proliferation, whereas right-handed nanofibers have the opposite effect. These effects are ascribed to the mediation of the stereospecific interaction between chiral nanofibers and fibronectin. The results stress the crucial role of the chirality of nanofibers on cell-adhesion and cell-proliferation behavior in 3D environments.

  1. Optical topography guided semi-three-dimensional diffuse optical tomography for a multi-layer model of occipital cortex: a pilot methodological study

    NASA Astrophysics Data System (ADS)

    Ding, Hao; Zhang, Yao; He, Jie; Zhao, Huijuan; Gao, Feng

    2016-03-01

    In this paper, an optical topography (OT) guided diffuse optical tomography (DOT) scheme is developed for functional imaging of the occipital cortex. The method extends the previously proposed semi-three-dimensional DOT methodology to reconstruction of two-dimensional extracerebral and cerebral images using a visual cortex oriented five-layered slab geometry, and incorporate the OT localization regularization in the cerebral reconstruction to achieve enhanced quantitative accuracy and spatial resolution. We validate the methodology using simulated data and demonstrate its merits in comparison to the standalone OT and DOT.

  2. Real-time three-dimensional optical coherence tomography image-guided core-needle biopsy system

    PubMed Central

    Kuo, Wei-Cheng; Kim, Jongsik; Shemonski, Nathan D.; Chaney, Eric J.; Spillman, Darold R.; Boppart, Stephen A.

    2012-01-01

    Advances in optical imaging modalities, such as optical coherence tomography (OCT), enable us to observe tissue microstructure at high resolution and in real time. Currently, core-needle biopsies are guided by external imaging modalities such as ultrasound imaging and x-ray computed tomography (CT) for breast and lung masses, respectively. These image-guided procedures are frequently limited by spatial resolution when using ultrasound imaging, or by temporal resolution (rapid real-time feedback capabilities) when using x-ray CT. One feasible approach is to perform OCT within small gauge needles to optically image tissue microstructure. However, to date, no system or core-needle device has been developed that incorporates both three-dimensional OCT imaging and tissue biopsy within the same needle for true OCT-guided core-needle biopsy. We have developed and demonstrate an integrated core-needle biopsy system that utilizes catheter-based 3-D OCT for real-time image-guidance for target tissue localization, imaging of tissue immediately prior to physical biopsy, and subsequent OCT imaging of the biopsied specimen for immediate assessment at the point-of-care. OCT images of biopsied ex vivo tumor specimens acquired during core-needle placement are correlated with corresponding histology, and computational visualization of arbitrary planes within the 3-D OCT volumes enables feedback on specimen tissue type and biopsy quality. These results demonstrate the potential for using real-time 3-D OCT for needle biopsy guidance by imaging within the needle and tissue during biopsy procedures. PMID:22741064

  3. Dual-wavelength optical-resolution photoacoustic microscopy for cells with gold nanoparticle bioconjugates in three-dimensional cultures

    NASA Astrophysics Data System (ADS)

    Lee, Po-Yi; Liu, Wei-Wen; Chen, Shu-Ching; Li, Pai-Chi

    2016-03-01

    Three-dimensional (3D) in vitro models bridge the gap between typical two-dimensional cultures and in vivo conditions. However, conventional optical imaging methods such as confocal microscopy and two-photon microscopy cannot accurately depict cellular processing in 3D models due to limited penetration of photons. We developed a dualwavelength optical-resolution photoacoustic microscopy (OR-PAM), which provides sufficient penetration depth and spatial resolution, for studying CD8+ cytotoxic T lymphocytes (CTLs) trafficking in an in vitro 3D tumor microenvironment. CTLs play a cardinal role in host defense against tumor. Efficient trafficking of CTLs to the tumor microenvironment is a critical step for cancer immunotherapy. For the proposed system, gold nanospheres and indocyanine green (ICG) have been remarkable choices for contrast agents for photoacoustic signals due to their excellent biocompatibility and high optical absorption. With distinct absorption spectrums, targeted cells with gold nanospheres and ICG respectively can be identified by switching 523-nm and 800-nm laser irradiation. Moreover, we use an x-y galvanometer scanner to obtain high scanning rate. In the developed system, lateral and axial resolutions were designed at 1.6 μm and 5 μm, respectively. We successfully showed that dual-spectral OR-PAM can map either the distribution of CTLs with gold nanospheres at a visible wavelength of 523 nm or the 3D structure of tumor spheres with ICG in an in vitro 3D microenvironment. Our OR-PAM can provide better biological relevant information in cellular interaction and is potential for preclinical screening of anti-cancer drugs.

  4. Continuous Three-Dimensional Control of a Virtual Helicopter Using a Motor Imagery Based Brain-Computer Interface

    PubMed Central

    Doud, Alexander J.; Lucas, John P.; Pisansky, Marc T.; He, Bin

    2011-01-01

    Brain-computer interfaces (BCIs) allow a user to interact with a computer system using thought. However, only recently have devices capable of providing sophisticated multi-dimensional control been achieved non-invasively. A major goal for non-invasive BCI systems has been to provide continuous, intuitive, and accurate control, while retaining a high level of user autonomy. By employing electroencephalography (EEG) to record and decode sensorimotor rhythms (SMRs) induced from motor imaginations, a consistent, user-specific control signal may be characterized. Utilizing a novel method of interactive and continuous control, we trained three normal subjects to modulate their SMRs to achieve three-dimensional movement of a virtual helicopter that is fast, accurate, and continuous. In this system, the virtual helicopter's forward-backward translation and elevation controls were actuated through the modulation of sensorimotor rhythms that were converted to forces applied to the virtual helicopter at every simulation time step, and the helicopter's angle of left or right rotation was linearly mapped, with higher resolution, from sensorimotor rhythms associated with other motor imaginations. These different resolutions of control allow for interplay between general intent actuation and fine control as is seen in the gross and fine movements of the arm and hand. Subjects controlled the helicopter with the goal of flying through rings (targets) randomly positioned and oriented in a three-dimensional space. The subjects flew through rings continuously, acquiring as many as 11 consecutive rings within a five-minute period. In total, the study group successfully acquired over 85% of presented targets. These results affirm the effective, three-dimensional control of our motor imagery based BCI system, and suggest its potential applications in biological navigation, neuroprosthetics, and other applications. PMID:22046274

  5. Three-dimensionally modulated anisotropic structure for diffractive optical elements created by one-step three-beam polarization holographic photoalignment

    SciTech Connect

    Kawai, Kotaro Sakamoto, Moritsugu; Noda, Kohei; Sasaki, Tomoyuki; Ono, Hiroshi; Kawatsuki, Nobuhiro

    2016-03-28

    A diffractive optical element with a three-dimensional liquid crystal (LC) alignment structure for advanced control of polarized beams was fabricated by a highly efficient one-step photoalignment method. This study is of great significance because different two-dimensional continuous and complex alignment patterns can be produced on two alignment films by simultaneously irradiating an empty glass cell composed of two unaligned photocrosslinkable polymer LC films with three-beam polarized interference beam. The polarization azimuth, ellipticity, and rotation direction of the diffracted beams from the resultant LC grating widely varied depending on the two-dimensional diffracted position and the polarization states of the incident beams. These polarization diffraction properties are well explained by theoretical analysis based on Jones calculus.

  6. Three-dimensionally modulated anisotropic structure for diffractive optical elements created by one-step three-beam polarization holographic photoalignment

    NASA Astrophysics Data System (ADS)

    Kawai, Kotaro; Sakamoto, Moritsugu; Noda, Kohei; Sasaki, Tomoyuki; Kawatsuki, Nobuhiro; Ono, Hiroshi

    2016-03-01

    A diffractive optical element with a three-dimensional liquid crystal (LC) alignment structure for advanced control of polarized beams was fabricated by a highly efficient one-step photoalignment method. This study is of great significance because different two-dimensional continuous and complex alignment patterns can be produced on two alignment films by simultaneously irradiating an empty glass cell composed of two unaligned photocrosslinkable polymer LC films with three-beam polarized interference beam. The polarization azimuth, ellipticity, and rotation direction of the diffracted beams from the resultant LC grating widely varied depending on the two-dimensional diffracted position and the polarization states of the incident beams. These polarization diffraction properties are well explained by theoretical analysis based on Jones calculus.

  7. Modeling and boundary control of translational and rotational motions of nonlinear slender beams in three-dimensional space

    NASA Astrophysics Data System (ADS)

    Do, K. D.

    2017-02-01

    Equations of motion of extensible and shearable slender beams with large translational and rotational motions under external loads in three-dimensional space are first derived in a vector form. Boundary feedback controllers are then designed to ensure that the beams are practically K∞-exponentially stable at the equilibrium. The control design, well-posedness, and stability analysis are based on two Lyapunov-type theorems developed for a class of evolution systems in Hilbert space. Numerical simulations on a slender beam immersed in sea water are included to illustrate the effectiveness of the proposed control design.

  8. 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.

  9. 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

  10. Three dimensional mesoscale analysis of translamellar cross-bridge morphologies in the annulus fibrosus using optical coherence tomography.

    PubMed

    Han, Sang Kuy; Chen, Chao-Wei; Wierwille, Jerry; Chen, Yu; Hsieh, Adam H

    2015-03-01

    The defining characteristic of the annulus fibrosus (AF) of the intervertebral disc (IVD) has long been the lamellar structures that consist of highly ordered collagen fibers arranged in alternating oblique angles from one layer to the next. However, a series of recent histologic studies have demonstrated that AF lamellae contain elastin- and type VI collagen-rich secondary "cross-bridge" structures across lamellae. In this study, we use optical coherence tomography (OCT) to elucidate the three-dimensional (3-D) morphologies of these translamellar cross-bridges in AF tissues. Mesoscale volumetric images by OCT revealed a 3-D network of heterogeneously distributed cross-bridges. The results of this study confirm the translamellar cross-bridge is identifiable as a distinguishable structure, which lies in the interbundle space of adjacent lamellae and crisscrosses multiple lamellae in the radial direction. In contrast to previously proposed models extrapolated from 2-D sections, results from this current study show that translamellar cross-bridges exist as a complex, interconnected network. We also found much greater variation in lengths of cross-bridges within the interbundle space of lamellae (0.8-1.4 mm from the current study versus 0.3-0.6 mm from 2-D sections). OCT-based 3-D morphology of translamellar cross-bridge provides novel insight into the AF structure.

  11. In vivo three-dimensional imaging of human corneal nerves using Fourier-domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Shin, Jun Geun; Hwang, Ho Sik; Eom, Tae Joong; Lee, Byeong Ha

    2017-01-01

    We have employed Fourier-domain optical coherence tomography (FD-OCT) to achieve corneal nerve imaging, which could be useful in surgical planning and refractive surgery. Because the three-dimensional (3-D) images of the corneal nerves were acquired in vivo, unintentional movement of the subject during the measurement led to imaging artifacts. These artifacts were compensated for with a series of signal processing techniques, namely realigning A-scan images to flatten the boundary and cross-correlating adjacent B-scan images. To overcome the undesirably large signal from scattering at the corneal surface and iris, volume rendering and maximum intensity projections were performed with only the data taken in the stromal region of the cornea, which is located between 200 and 500 μm from the corneal surface. The 3-D volume imaging of a 10×10 mm2 area took 9.8 s, which is slightly shorter than the normal tear breakup time. This allowed us to image the branched and threadlike corneal nerve bundles within the human eye. The experimental results show that FD-OCT systems have the potential to be useful in clinical investigations of corneal nerves and by minimizing nerve injury during clinical or surgical procedures.

  12. 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.

  13. Microvascular anastomosis guidance and evaluation using real-time three-dimensional Fourier-domain Doppler optical coherence tomography

    PubMed Central

    Ibrahim, Zuhaib; Tong, Dedi; Zhu, Shan; Mao, Qi; Pang, John; Andrew Lee, Wei Ping; Brandacher, Gerald; Kang, Jin U.

    2013-01-01

    Abstract. Vascular and microvascular anastomoses are critical components of reconstructive microsurgery, vascular surgery, and transplant surgery. Intraoperative surgical guidance using a surgical imaging modality that provides an in-depth view and three-dimensional (3-D) imaging can potentially improve outcome following both conventional and innovative anastomosis techniques. Objective postoperative imaging of the anastomosed vessel can potentially improve the salvage rate when combined with other clinical assessment tools, such as capillary refill, temperature, blanching, and skin turgor. Compared to other contemporary postoperative monitoring modalities—computed tomography angiograms, magnetic resonance (MR) angiograms, and ultrasound Doppler—optical coherence tomography (OCT) is a noninvasive high-resolution (micron-level), high-speed, 3-D imaging modality that has been adopted widely in biomedical and clinical applications. For the first time, to the best of our knowledge, the feasibility of real-time 3-D phase-resolved Doppler OCT (PRDOCT) as an assisted intra- and postoperative imaging modality for microvascular anastomosis of rodent femoral vessels is demonstrated, which will provide new insights and a potential breakthrough to microvascular and supermicrovascular surgery. PMID:23856833

  14. Automated framework for intraretinal cystoid macular edema segmentation in three-dimensional optical coherence tomography images with macular hole

    NASA Astrophysics Data System (ADS)

    Zhu, Weifang; Zhang, Li; Shi, Fei; Xiang, Dehui; Wang, Lirong; Guo, Jingyun; Yang, Xiaoling; Chen, Haoyu; Chen, Xinjian

    2017-07-01

    Cystoid macular edema (CME) and macular hole (MH) are the leading causes for visual loss in retinal diseases. The volume of the CMEs can be an accurate predictor for visual prognosis. This paper presents an automatic method to segment the CMEs from the abnormal retina with coexistence of MH in three-dimensional-optical coherence tomography images. The proposed framework consists of preprocessing and CMEs segmentation. The preprocessing part includes denoising, intraretinal layers segmentation and flattening, and MH and vessel silhouettes exclusion. In the CMEs segmentation, a three-step strategy is applied. First, an AdaBoost classifier trained with 57 features is employed to generate the initialization results. Second, an automated shape-constrained graph cut algorithm is applied to obtain the refined results. Finally, cyst area information is used to remove false positives (FPs). The method was evaluated on 19 eyes with coexistence of CMEs and MH from 18 subjects. The true positive volume fraction, FP volume fraction, dice similarity coefficient, and accuracy rate for CMEs segmentation were 81.0%±7.8%, 0.80%±0.63%, 80.9%±5.7%, and 99.7%±0.1%, respectively.

  15. 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

  16. 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.

  17. A high sensitivity multi-spectral three-dimensional fluorescence optical tomography system for small animal imaging

    NASA Astrophysics Data System (ADS)

    Li, Changqing; Mitchell, Gregory S.; Dutta, Joyita; Ahn, Sangtae; Leahy, Richard M.; Cherry, Simon R.

    2009-02-01

    We have designed a three dimensional (3D) fluorescence optical tomography system for small animal imaging based on an innovative system geometry that uses a truncated conical mirror which permits the entire surface of the animal to be viewed simultaneously by a single CCD camera. Compared with traditional approaches that employ a flat mirror, the conical mirror system has approximately 3 times better measurement sensitivity. By utilizing a fast switching filter wheel (switching time < 100 milliseconds), emission data at multiple wavelengths can be efficiently collected. An array of appropriately shaped neutral density filters, mounted on a linear stage, can be used to increase the system measurement dynamic range by 3 orders of magnitude. An x-y galvo mirror scanning system makes it possible to scan a collimated laser beam to any location on the mouse surface. A pattern of structured light incident on the animal surface is used to extract the surface geometry. A finite element based algorithm is applied to model photon propagation in the turbid media and a preconditioned conjugate gradient (PCG) method is used to solve the large linear system matrix. The reconstruction algorithm and the system performance are evaluated by phantom experiments.

  18. Variations in three-dimensional cancellous bone architecture of the proximal femur in female hip fractures and in controls.

    PubMed

    Ciarelli, T E; Fyhrie, D P; Schaffler, M B; Goldstein, S A

    2000-01-01

    Cubes of cancellous bone were obtained from proximal femora of women with hip fractures (n = 26) and from female cadaveric controls (n = 32) to compare architecture and mechanics between groups. Specimens were scanned on a microcomputed tomography system. Stereologic algorithms and model-based estimates were applied to the data to characterize the three-dimensional cancellous microstructure. Cubes were mechanically tested to failure to obtain mechanical properties. Specimens from control subjects had significantly higher bone volume fraction, trabecular number, and connectivity than specimens from patients with hip fractures; no difference in trabecular thickness was observed between groups. Both maximum modulus and ultimate stress were significantly higher in the control than in the fracture group, consistent with the higher bone volume found in the control group. No statistical differences in any of these architectural or mechanical variables were found when groups were matched for bone volume. Specimens from both patients with hip fractures and controls demonstrated strong relationships between trabecular number and bone volume fraction that were statistically equivalent, suggesting that for a given bone mass, both groups have the same overall number of trabeculae. However, there was an architectural difference between fracture and control groups in terms of the three-dimensional spatial arrangement of trabeculae. Fracture specimens had a significantly more anisotropic (oriented) structure than control specimens, with proportionately fewer trabecular elements transverse to the primary load axis, even when matched for bone volume. Relationships between mechanical and architectural parameters were significantly different between groups, suggesting that fracture and control groups have different structure-mechanics relationships, which we hypothesize may be a consequence of the altered three-dimensional structure between groups.

  19. Three Dimensionally Interconnected Silicon Nanomembranes for Optical Phased Array (OPA) and Optical True Time Delay (TTD) Applications

    DTIC Science & Technology

    2012-06-01

    Freude , "High-speed low-voltage electro-optic modulator with a polymer-infiltrated silicon photonic crystal waveguide," Optics Express 16 (6), 4177...Lett. 97, 093304 (2010). [9-3] J.-M. Brosi, C. Koos, L. C. Andreani, M. Waldow, J. Leuthold, and W. Freude , Optics Express 16, 4177 (2008). [9-4

  20. Control of the pore architecture in three-dimensional hydroxyapatite-reinforced hydrogel scaffolds.

    PubMed

    Román, Jesús; Cabañas, María Victoria; Peña, Juan; Vallet-Regí, María

    2011-08-01

    Hydrogels (gellan or agarose) reinforced with nanocrystalline carbonated hydroxyapatite (nCHA) were prepared by the GELPOR3D technique. This simple method is characterized by compositional flexibility; it does not require expensive equipment, thermal treatment, or aggressive or toxic solvents, and yields a three-dimensional (3D) network of interconnected pores 300-900 μm in size. In addition, an interconnected porosity is generated, yielding a hierarchical porous architecture from the macro to the molecular scale. This porosity depends on both the drying/preservation technology (freeze drying or oven drying at 37 (○)C) and on the content and microstructure of the reinforcing ceramic. For freeze-dried samples, the porosities were approximately 30, 66 and below 3% for pore sizes of 600-900 μm, 100-200 μm and 50-100 nm, respectively. The pore structure depends much on the ceramic content, so that higher contents lead to the disappearance of the characteristic honeycomb structure observed in low-ceramic scaffolds and to a lower fraction of the 100-200-μm-sized pores. The nature of the hydrogel did not affect the pore size distribution but was crucial for the behavior of the scaffolds in a hydrated medium: gellan-containing scaffolds showed a higher swelling degree owing to the presence of more hydrophilic groups.

  1. Three-Dimensional Mapping of Microenvironmental Control of Methyl Rotational Barriers

    SciTech Connect

    Hembree, William I; Baudry, Jerome Y

    2011-01-01

    Sterical (van der Waals-induced) rotational barriers of methyl groups are investigated theoretically, using ab initio and empirical force field calculations, for various three-dimensional microenvironmental conditions around the methyl group rotator of a model neopentane molecule. The destabilization (reducing methyl rotational barriers) or stabilization (increasing methyl rotational barriers) of the staggered conformation of the methyl rotator depends on a combination of microenvironmental contributions from (i) the number of atoms around the rotator, (ii) the distance between the rotator and the microenvironmental atoms, and (iii) the dihedral angle between the stator, rotator, and molecular environment around the rotator. These geometrical criteria combine their respective effects in a linearly additive fashion, with no apparent cooperative effects, and their combination in space around a rotator may increase, decrease, or leave the rotator s rotational barrier unmodified. This is exemplified in a geometrical analysis of the alanine dipeptide crystal where microenvironmental effects on methyl rotators barrier of rotation fit the geometrical mapping described in the neopentane model.

  2. Three-Dimensional Printing of Photoresponsive Biomaterials for Control of Bacterial Microenvironments.

    PubMed

    Connell, Jodi L; Ritschdorff, Eric T; Shear, Jason B

    2016-12-20

    Advances in microscopic three-dimensional (μ3D) printing provide a means to microfabricate an almost limitless range of arbitrary geometries, offering new opportunities to rapidly prototype complex architectures for microfluidic and cellular applications. Such 3D lithographic capabilities present a tantalizing prospect for engineering micromechanical components, for example, pumps and valves, for cellular environments composed of smart materials whose size, shape, permeability, stiffness, and other attributes might be modified in real time to precisely manipulate ultralow-volume samples. Unfortunately, most materials produced using μ3D printing are synthetic polymers that are inert to biologically tolerated chemical and light-based triggers and provide low compatibility as materials for cell culture and encapsulation applications. We previously demonstrated feasibility for μ3D printing environmentally sensitive, microstructured protein hydrogels that undergo volume changes in response to pH, ionic strength, and thermal triggers, cues that may be incompatible with sensitive chemical and biological systems. Here, we report the systematic investigation of photoillumination as a minimally invasive and remotely applied means to trigger morphological change in protein-based μ3D-printed smart materials. Detailed knowledge of material responsiveness is exploited to develop individually addressable "smart" valves that can be used to capture, "farm", and then dilute motile bacteria at specified times in multichamber picoliter edifices, capabilities that offer new opportunities for studying cell-cell interactions in ultralow-volume environments.

  3. Three-dimensional multilayered nanostructures with controlled orientation of microdomains from cross-linkable block copolymers.

    PubMed

    Jung, Hyunjung; Hwang, Dongjune; Kim, Eunhye; Kim, Byung-Jae; Lee, Won Bo; Poelma, Justin E; Kim, Jihyun; Hawker, Craig J; Huh, June; Ryu, Du Yeol; Bang, Joona

    2011-08-23

    Three-dimensional (3D) nanostructures were obtained by the directed formation of multilayer block copolymer (BCP) thin films. The initial step in this strategy involves the assembly and cross-linking of cylinder-forming polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) BCP, in which 1.5 mol % of reactive azido (-N(3)) groups were randomly incorporated along the styrene backbone. Significantly, assembly of thin films of lamellar-forming BCPs on top of the underlying cross-linked cylindrical layer exhibited perpendicular orientations of microdomains between lamellae and cylinder layers. From the theoretical calculation of free energy in the multilayers, it was found that the nematic interactions between polymer chains at the interface play a critical role in the perpendicular orientation of lamellae on the cross-linked cylinder layers. Removal of the PMMA domains then affords nonsymmetrical nanostructures which illustrate the promise of this strategy for the design of well-defined 3D nanotemplates. It was also demonstrated that this structure can be effectively used to enhance the light extraction efficiency of GaN light-emitting diodes. Furthermore, we anticipate that such 3D nanotemplates can be applied to various areas, including advanced BCP nanolithography and responsive surface coating. © 2011 American Chemical Society

  4. Control of the pore architecture in three-dimensional hydroxyapatite-reinforced hydrogel scaffolds

    PubMed Central

    Román, Jesús; Cabañas, María Victoria; Peña, Juan; Vallet-Regí, María

    2011-01-01

    Hydrogels (gellan or agarose) reinforced with nanocrystalline carbonated hydroxyapatite (nCHA) were prepared by the GELPOR3D technique. This simple method is characterized by compositional flexibility; it does not require expensive equipment, thermal treatment, or aggressive or toxic solvents, and yields a three-dimensional (3D) network of interconnected pores 300–900 μm in size. In addition, an interconnected porosity is generated, yielding a hierarchical porous architecture from the macro to the molecular scale. This porosity depends on both the drying/preservation technology (freeze drying or oven drying at 37 ○C) and on the content and microstructure of the reinforcing ceramic. For freeze-dried samples, the porosities were approximately 30, 66 and below 3% for pore sizes of 600–900 μm, 100–200 μm and 50–100 nm, respectively. The pore structure depends much on the ceramic content, so that higher contents lead to the disappearance of the characteristic honeycomb structure observed in low-ceramic scaffolds and to a lower fraction of the 100–200-μm-sized pores. The nature of the hydrogel did not affect the pore size distribution but was crucial for the behavior of the scaffolds in a hydrated medium: gellan-containing scaffolds showed a higher swelling degree owing to the presence of more hydrophilic groups. PMID:27877422

  5. The Use of Optical Clearing and Multiphoton Microscopy for Investigation of Three-Dimensional Tissue-Engineered Constructs

    PubMed Central

    Calle, Elizabeth A.; Vesuna, Sam; Dimitrievska, Sashka; Zhou, Kevin; Huang, Angela; Zhao, Liping; Niklason, Laura E.

    2014-01-01

    Recent advances in three-dimensional (3D) tissue engineering have concomitantly generated a need for new methods to visualize and assess the tissue. In particular, methods for imaging intact volumes of whole tissue, rather than a single plane, are required. Herein, we describe the use of multiphoton microscopy, combined with optical clearing, to noninvasively probe decellularized lung extracellular matrix scaffolds and decellularized, tissue-engineered blood vessels. We also evaluate recellularized lung tissue scaffolds. In addition to nondestructive imaging of tissue volumes greater than 4 mm3, the lung tissue can be visualized using three distinct signals, combined or singly, that allow for simple separation of cells and different components of the extracellular matrix. Because the 3D volumes are not reconstructions, they do not require registration algorithms to generate digital volumes, and maintenance of isotropic resolution is not required when acquiring stacks of images. Once a virtual volume of tissue is generated, structures that have innate 3D features, such as the lumens of vessels and airways, are easily animated and explored in all dimensions. In blood vessels, individual collagen fibers can be visualized at the micron scale and their alignment assessed at various depths through the tissue, potentially providing some nondestructive measure of vessel integrity and mechanics. Finally, both the lungs and vessels assayed here were optically cleared, imaged, and visualized in a matter of hours, such that the added benefits of these techniques can be achieved with little more hassle or processing time than that associated with traditional histological methods. PMID:24251630

  6. Qualitative and quantitative evaluation of human dental enamel after bracket debonding: a noncontact three-dimensional optical profilometry analysis.

    PubMed

    Ferreira, Fabiano G; Nouer, Darcy F; Silva, Nelson P; Garbui, Ivana U; Correr-Sobrinho, Lourenço; Nouer, Paulo R A

    2014-09-01

    The aim of this study was to undertake a qualitative and quantitative evaluation of changes on enamel surfaces after debonding of brackets followed by finishing procedures, using a high-resolution three-dimensional optical profiler and to investigate the accuracy of the technique. The labial surfaces of 36 extracted upper central incisors were examined. Before bonding, the enamel surfaces were subjected to profilometry, recording four amplitude parameters. Brackets were then bonded using two types of light-cured orthodontic adhesive: composite resin and resin-modified glass ionomer cement. Finishing was performed by three different methods: pumice on a rubber cup, fine and ultrafine aluminum oxide discs, and microfine diamond cups followed by silicon carbide brushes. The samples were subsequently re-analyzed by profilometry. Wilcoxon signed-rank test, Kruskal-Wallis test (p < 0.05) and a posteriori Mann-Whitney U test with Bonferroni correction (p < 0.0167) revealed a significant reduction of enamel roughness when diamond cups followed by silicon carbide brushes were used to finish surfaces that had remnants of resin-modified glass ionomer adhesive and when pumice was used to finish surfaces that had traces of composite resin. Enamel loss was minimal. The 3D optical profilometry technique was able to provide accurate qualitative and quantitative assessment of changes on the enamel surface after debonding. Morphological changes in the topography of dental surfaces, especially if related to enamel loss and roughness, are of considerable clinical importance. The quantitative evaluation method used herein enables a more comprehensive understanding of the effects of orthodontic bonding on teeth.

  7. Optical fiber tip with point light source of SPPs driven by three-dimensional nanostructured asymmetric metal-insulator-metal layer cap

    NASA Astrophysics Data System (ADS)

    Oshikane, Yasushi; Murai, Kensuke; Nakano, Motohiro

    2015-09-01

    Numerical analysis of three dimensional optical electro-magnetic field in a circular-truncated conical optical fiber covered by asymmetric MIM structure has been performed by a commercial finite element method package, COMSOL Multiphysics coupled with Wave Optics Module. The outermost thick metallic layer has twin nano-hole, and the waveguiding twin-hole could draw surface plasmon polaritions (SPPs) excited in the MIM structure to the surface. Finally the guided two SPPs could unite each other and may create a single bright spot. The systematic simulation is continuing, and the results will give us valuable counsel for control of surface plasmon polaritons (SPPs) appearing around the MIM structure and twin nano-hole. (1) Optimal design of the 3D FEM model for 8-core Xeon server and rational approach for the FEM analysis, (2) behavior of SPPs affected by wavelength and polarization of light travel through fiber, (3) change in excitation condition of SPPs caused by shape of the MIM structure and twin-hole, (4) effectiveness of additional nanostructures that are aimed at focusing control of two SPPs come out from the corners of twin-hole, (5) scanning ability of the MIM/twin-hole probe at nanostructured sample surface (i.e. amount of forward and backward scattering of SPPs) will be presented and discussed. Several FIBed prototypes and their characteristic of light emission will also reported.

  8. Randomized controlled clinical trial on the three-dimensional accuracy of fast-set impression materials.

    PubMed

    Rudolph, Heike; Quaas, Sebastian; Haim, Manuela; Preißler, Jörg; Walter, Michael H; Koch, Rainer; Luthardt, Ralph G

    2013-06-01

    The use of fast-setting impression materials with different viscosities for the one-stage impression technique demands precise working times when mixing. We examined the effect of varying working time on impression precision in a randomized clinical trial. Focusing on tooth 46, three impressions were made from each of 96 volunteers, using either a polyether (PE: Impregum Penta H/L DuoSoft Quick, 3 M ESPE) or an addition-curing silicone (AS: Aquasil Ultra LV, Dentsply/DeTrey), one with the manufacturer's recommended working time (used as a reference) and two with altered working times. All stages of the impression-taking were subject to randomization. The three-dimensional precision of the non-standard working time impressions was digitally analyzed compared to the reference impression. Statistical analysis was performed using multivariate models. The mean difference in the position of the lower right first molar (vs. the reference impression) ranged from ±12 μm for PE to +19 and -14 μm for AS. Significantly higher mean values (+62 to -40 μm) were found for AS compared to PE (+21 to -26 μm) in the area of the distal adjacent tooth. Fast-set impression materials offer high precision when used for single tooth restorations as part of a one-stage impression technique, even when the working time (mixing plus application of the light- and heavy-body components) diverges significantly from the manufacturer's recommended protocol. Best accuracy was achieved with machine-mixed heavy-body/light-body polyether. Both materials examined met the clinical requirements regarding precision when the teeth were completely syringed with light material.

  9. Controlled chaos: three-dimensional kinematics, fiber histochemistry, and muscle contractile dynamics of autotomized lizard tails.

    PubMed

    Higham, Timothy E; Lipsett, Kathryn R; Syme, Douglas A; Russell, Anthony P

    2013-01-01

    The ability to shed an appendage occurs in both vertebrates and invertebrates, often as a tactic to avoid predation. The tails of lizards, unlike most autotomized body parts of animals, exhibit complex and vigorous movements once disconnected from the body. Despite the near ubiquity of autotomy across groups of lizards and the fact that this is an extraordinary event involving the self-severing of the spinal cord, our understanding of why and how tails move as they do following autotomy is sparse. We herein explore the histochemistry and physiology of the tail muscles of the leopard gecko (Eublepharis macularius), a species that exhibits vigorous and variable tail movements following autotomy. To confirm that the previously studied tail movements of this species are generally representative of geckos and therefore suitable for in-depth muscle studies, we quantified the three-dimensional kinematics of autotomized tails in three additional species. The movements of the tails of all species were generally similar and included jumps, flips, and swings. Our preliminary analyses suggest that some species of gecko exhibit short but high-frequency movements, whereas others exhibit larger-amplitude but lower-frequency movements. We then compared the ATPase and oxidative capacity of muscle fibers and contractile dynamics of isolated muscle bundles from original tails, muscle from regenerate tails, and fast fibers from an upper limb muscle (iliofibularis) of the leopard gecko. Histochemical analysis revealed that more than 90% of the fibers in original and regenerate caudal muscles had high ATPase but possessed a superficial layer of fibers with low ATPase and high oxidative capacity. We found that contraction kinetics, isometric force, work, power output, and the oscillation frequency at which maximum power was generated were lowest in the original tail, followed by the regenerate tail and then the fast fibers of the iliofibularis. Muscle from the original tail exhibited

  10. Morphometrical study of plant vacuolar dynamics in single cells using three-dimensional reconstruction from optical sections.

    PubMed

    Kutsuna, Natsumaro; Hasezawa, Seiichiro

    2005-12-01

    In higher plants, vacuoles increase their volumes in accordance with cell enlargement and occupy most of the cell volume. However, quantitative analyses of vacuolar contributions during changes in cell morphology have been hampered by the inadequacies and frequent artifacts associated with current three-dimensional (3-D) reconstruction methods of images derived from light microscopy. To overcome the limitations of quantifying 3-D structures, we have introduced 3-D morphometrics into light microscopy, adopting a contour-based approach for which we have developed an interpolation method. Using this software, named REANT, the morphological and morphometrical changes in protoplasts and vacuoles during plasmolysis could be investigated. We employed the tobacco (Nicotiana tabacum) BY-2 cell line No.7, expressing a GFP-AtVam3p fusion protein, BY-GV7, using GFP as a marker of vacuolar membranes (VMs). By vital staining of the plasma membrane (PM) of cells, we simultaneously obtained optical sections of both the PM and VM. We, therefore, reconstructed the 3-D structures of protoplasts and vacuoles before and after plasmolysis. We were able to identify the appearance of elliptical structures of VMs in the vacuolar lumen, and to determine that they were derived from cytoplasmic strands. From the 3-D structures, the volumes and surface areas were measured at the single cell level. The shrinkage of vacuoles accounted for most of the decrease in protoplast volume, while the surface area of the vacuoles remained mostly unchanged. These morphometrical analyses suggest that the elliptical structures are reservoirs for excess VMs that result from the response to rapid decreases in vacuolar and protoplast volumes. (c) 2005 Wiley-Liss, Inc.

  11. Three-dimensional (3D) evaluation of liquid distribution in shake flask using an optical fluorescence technique.

    PubMed

    Azizan, Amizon; Büchs, Jochen

    2017-01-01

    Biotechnological development in shake flask necessitates vital engineering parameters e.g. volumetric power input, mixing time, gas liquid mass transfer coefficient, hydromechanical stress and effective shear rate. Determination and optimization of these parameters through experiments are labor-intensive and time-consuming. Computational Fluid Dynamics (CFD) provides the ability to predict and validate these parameters in bioprocess engineering. This work provides ample experimental data which are easily accessible for future validations to represent the hydrodynamics of the fluid flow in the shake flask. A non-invasive measuring technique using an optical fluorescence method was developed for shake flasks containing a fluorescent solution with a waterlike viscosity at varying filling volume (VL = 15 to 40 mL) and shaking frequency (n = 150 to 450 rpm) at a constant shaking diameter (do = 25 mm). The method detected the leading edge (LB) and tail of the rotating bulk liquid (TB) relative to the direction of the centrifugal acceleration at varying circumferential heights from the base of the shake flask. The determined LB and TB points were translated into three-dimensional (3D) circumferential liquid distribution plots. The maximum liquid height (Hmax) of the bulk liquid increased with increasing filling volume and shaking frequency of the shaking flask, as expected. The toroidal shapes of LB and TB are clearly asymmetrical and the measured TB differed by the elongation of the liquid particularly towards the torus part of the shake flask. The 3D liquid distribution data collected at varying filling volume and shaking frequency, comprising of LB and TB values relative to the direction of the centrifugal acceleration are essential for validating future numerical solutions using CFD to predict vital engineering parameters in shake flask.

  12. Five beam holographic lithography for simultaneous fabrication of three dimensional photonic crystal templates and line defects using phase tunable diffractive optical element.

    PubMed

    Lin, Yuankun; Harb, Ahmad; Lozano, Karen; Xu, Di; Chen, K P

    2009-09-14

    This paper demonstrates an approach for laser holographic patterning of three-dimensional photonic lattice structures using a single diffractive optical element. The diffractive optical element is fabricated by recording gratings in a photosensitive polymer using a two-beam interference method and has four diffraction gratings oriented with four-fold symmetry around a central opening. Four first-order diffracted beams from the gratings and one non-diffracted central beam overlap and form a three-dimensional interference pattern. The phase of one side beam is delayed by inserting a thin piece of microscope glass slide into the beam. By rotating the glass slide, thus tuning the phase of the side beam, the five beam interference pattern changes from face-center tetragonal symmetry into diamond-like lattice symmetry with an optimal bandgap. Three-dimensional photonic crystal templates are produced in a photoresist and show the phase tuning effect for bandgap optimization. Furthermore, by integrating an amplitude mask in the central opening, line defects are produced within the photonic crystal template. This paper presents the first experimental demonstration on the holographic fabrication approach of three-dimensional photonic crystal templates with functional defects by a single laser exposure using a single optical element.

  13. Impact angle constrained three-dimensional integrated guidance and control for STT missile in the presence of input saturation.

    PubMed

    Wang, Sen; Wang, Weihong; Xiong, Shaofeng

    2016-09-01

    Considering a class of skid-to-turn (STT) missile with fixed target and constrained terminal impact angles, a novel three-dimensional (3D) integrated guidance and control (IGC) scheme is proposed in this paper. Based on coriolis theorem, the fully nonlinear IGC model without the assumption that the missile flies heading to the target at initial time is established in the three-dimensional space. For this strict-feedback form of multi-variable system, dynamic surface control algorithm is implemented combining with extended observer (ESO) to complete the preliminary design. Then, in order to deal with the problems of the input constraints, a hyperbolic tangent function is introduced to approximate the saturation function and auxiliary system including a Nussbaum function established to compensate for the approximation error. The stability of the closed-loop system is proven based on Lyapunov theory. Numerical simulations results show that the proposed integrated guidance and control algorithm can ensure the accuracy of target interception with initial alignment angle deviation and the input saturation is suppressed with smooth deflection curves. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Size-controlled conformal nanofabrication of biotemplated three-dimensional TiO2 and ZnO nanonetworks

    PubMed Central

    Ceylan, Hakan; Ozgit-Akgun, Cagla; Erkal, Turan S.; Donmez, Inci; Garifullin, Ruslan; Tekinay, Ayse B.; Usta, Hakan; Biyikli, Necmi; Guler, Mustafa O.

    2013-01-01

    A solvent-free fabrication of TiO2 and ZnO nanonetworks is demonstrated by using supramolecular nanotemplates with high coating conformity, uniformity, and atomic scale size control. Deposition of TiO2 and ZnO on three-dimensional nanofibrous network template is accomplished. Ultrafine control over nanotube diameter allows robust and systematic evaluation of the electrochemical properties of TiO2 and ZnO nanonetworks in terms of size-function relationship. We observe hypsochromic shift in UV absorbance maxima correlated with decrease in wall thickness of the nanotubes. Photocatalytic activities of anatase TiO2 and hexagonal wurtzite ZnO nanonetworks are found to be dependent on both the wall thickness and total surface area per unit of mass. Wall thickness has effect on photoexcitation properties of both TiO2 and ZnO due to band gap energies and total surface area per unit of mass. The present work is a successful example that concentrates on nanofabrication of intact three-dimensional semiconductor nanonetworks with controlled band gap energies. PMID:23892593

  15. Three-dimensional pointwise comparison of human retinal optical property at 845 and 1060 nm using optical frequency domain imaging

    NASA Astrophysics Data System (ADS)

    Chen, Yueli; Burnes, Daina L.; de Bruin, Martijn; Mujat, Mircea; de Boer, Johannes F.

    2009-03-01

    To compare the optical properties of the human retina, 3-D volumetric images of the same eye are acquired with two nearly identical optical coherence tomography (OCT) systems at center wavelengths of 845 and 1060 nm using optical frequency domain imaging (OFDI). To characterize the contrast of individual tissue layers in the retina at these two wavelengths, the 3-D volumetric data sets are carefully spatially matched. The relative scattering intensities from different layers such as the nerve fiber, photoreceptor, pigment epithelium, and choroid are measured and a quantitative comparison is presented. OCT retinal imaging at 1060 nm is found to have a significantly better depth penetration but a reduced contrast between the retinal nerve fiber, the ganglion cell, and the inner plexiform layers compared to the OCT retinal imaging at 845 nm.

  16. Three-dimensional pointwise comparison of human retinal optical property at 845 and 1060 nm using optical frequency domain imaging.

    PubMed

    Chen, Yueli; Burnes, Daina L; de Bruin, Martijn; Mujat, Mircea; de Boer, Johannes F

    2009-01-01

    To compare the optical properties of the human retina, 3-D volumetric images of the same eye are acquired with two nearly identical optical coherence tomography (OCT) systems at center wavelengths of 845 and 1060 nm using optical frequency domain imaging (OFDI). To characterize the contrast of individual tissue layers in the retina at these two wavelengths, the 3-D volumetric data sets are carefully spatially matched. The relative scattering intensities from different layers such as the nerve fiber, photoreceptor, pigment epithelium, and choroid are measured and a quantitative comparison is presented. OCT retinal imaging at 1060 nm is found to have a significantly better depth penetration but a reduced contrast between the retinal nerve fiber, the ganglion cell, and the inner plexiform layers compared to the OCT retinal imaging at 845 nm.

  17. Discrete and continuous description of a three-dimensional scene for quality control of radiotherapy treatment planning systems

    NASA Astrophysics Data System (ADS)

    Denis, Eloise; Guédon, JeanPierre; Beaumont, Stéphane; Normand, Nicolas

    2006-03-01

    Quality Control (QC) procedures are mandatory to achieve accuracy in radiotherapy treatments. For that purpose, classical methods generally use physical phantoms that are acquired by the system in place of the patient. In this paper, the use of digital test objects (DTO) replace the actual acquisition1. A DTO is a 3D scene description composed of simple and complex shapes from which discrete descriptions can be obtained. For QC needs, both the DICOM format (for Treatment Planning System (TPS) inputs) as well as continuous descriptions are required. The aim of this work is to define an equivalence model between a continuous description of the three dimensional (3D) scene used to define the DTO, and the DTO characteristics. The purpose is to have an XML- DTO description in order to compute discrete calculations from a continuous description. The defined structure allows also to obtain the three dimensional matrix of the DTO and then the series of slices stored in the DICOM format. Thus, it is shown how possibly design DTO for quality control in CT simulation and dosimetry.

  18. Preliminary investigations on the determination of three-dimensional dose distributions using scintillator blocks and optical tomography

    SciTech Connect

    Kroll, Florian; Karsch, Leonhard; Pawelke, Jörg

    2013-08-15

    Purpose: Clinical QA in teletherapy as well as the characterization of experimental radiation sources for future medical applications requires effective methods for measuring three-dimensional (3D) dose distributions generated in a water-equivalent medium. Current dosimeters based on ionization chambers, diodes, thermoluminescence detectors, radiochromic films, or polymer gels exhibit various drawbacks: High quality 3D dose determination is either very sophisticated and expensive or requires high amounts of effort and time for the preparation or read out. New detectors based on scintillator blocks in combination with optical tomography are studied, since they have the potential to facilitate the desired cost-effective, transportable, and long-term stable dosimetry system that is able to determine 3D dose distributions with high spatial resolution in a short time.Methods: A portable detector prototype was set up based on a plastic scintillator block and four digital cameras. During irradiation the scintillator emits light, which is detected by the fixed cameras. The light distribution is then reconstructed by optical tomography, using maximum-likelihood expectation maximization. The result of the reconstruction approximates the 3D dose distribution. First performance tests of the prototype using laser light were carried out. Irradiation experiments were performed with ionizing radiation, i.e., bremsstrahlung (6 to 21 MV), electrons (6 to 21 MeV), and protons (68 MeV), provided by clinical and research accelerators.Results: Laser experiments show that the current imaging properties differ from the design specifications: The imaging scale of the optical systems is position dependent, ranging from 0.185 mm/pixel to 0.225 mm/pixel. Nevertheless, the developed dosimetry method is proven to be functional for electron and proton beams. Induced radiation doses of 50 mGy or more made 3D dose reconstructions possible. Taking the imaging properties into account, determined

  19. Three-dimensional sensing, graphics, and interactive control in a human-machine system for decontamination and decommissioning applications

    NASA Astrophysics Data System (ADS)

    Thayer, Scott M.; Gourley, Christopher S.; Butler, Philip L.; Costello, Hugh; Trivedi, Mohan M.; Chen, ChuXin; Marapane, Suresh B.

    1992-11-01

    Decontamination and Decommissioning (D important requirement of the U.S. Department of Energy''s Environmental Restoration and Waste Management (ERWM) program. Means need to be devised to minimize radiation exposure to humans involved in the D research presented in this paper describes a human-machine system which can be employed for performing radiation scan and pipe cutting operations in a typical D Advanced Servomanipulator (ASM) from the Oak Ridge National Laboratory (ORNL), we have designed a hybrid telerobotic pipe-cutting module. The module, when fully integrated, will allow users of the ASM to exploit the original functionality of the telerobot when our pipe cutting system is not in use. Comprising the pipe-cutting system are interactive three- dimensional object localization, graphical task modeler, arm control, human-machine interface, radiation sensor, and cut-tool sub-systems. Only the task modeler and interactive object localization modules are discussed in this paper. The goal of these modules is to interactively localize an object, usually a pipe, and display it in a three-dimensional rendering of the work space. Through interaction with these modules, the supervisor coordinates a task- specific sequence of actions that the lower-level sub-systems will perform.

  20. Three-dimensional non-destructive optical evaluation of laser-processing performance using optical coherence tomography

    PubMed Central

    Kim, Youngseop; Choi, Eun Seo; Kwak, Wooseop; Shin, Yongjin; Jung, Woonggyu; Ahn, Yeh-Chan; Chen, Zhongping

    2014-01-01

    We demonstrate the use of optical coherence tomography (OCT) as a non-destructive diagnostic tool for evaluating laser-processing performance by imaging the features of a pit and a rim. A pit formed on a material at different laser-processing conditions is imaged using both a conventional scanning electron microscope (SEM) and OCT. Then using corresponding images, the geometrical characteristics of the pit are analyzed and compared. From the results, we could verify the feasibility and the potential of the application of OCT to the monitoring of the laser-processing performance. PMID:24932051

  1. Vital effects in coral skeletal composition display strict three-dimensional control

    NASA Astrophysics Data System (ADS)

    Meibom, Anders; Yurimoto, Hiyayoshi; Cuif, Jean-Pierre; Domart-Coulon, Isabelle; Houlbreque, Fanny; Constantz, Brent; Dauphin, Yannicke; Tambutté, E.; Tambutté, Sylvie; Allemand, Denis; Wooden, Joseph; Dunbar, Robert

    2006-06-01

    Biological control over coral skeletal composition is poorly understood but critically important to paleo-environmental reconstructions. We present micro-analytical measurements of trace-element abundances as well as oxygen and carbon isotopic compositions of individual skeletal components in the zooxanthellate coral Colpophyllia sp. Our data show that centers of calcification (COC) have higher trace element concentrations and distinctly lighter isotopic compositions than the fibrous components of the skeleton. These observations necessitate that COC and the fibrous skeleton are precipitated by different mechanisms, which are controlled by specialized domains of the calicoblastic cell-layer. Biological processes control the composition of the skeleton even at the ultra-structure level.

  2. Three-dimensional position control of a parallel micromanipulator using visual servoing

    NASA Astrophysics Data System (ADS)

    Kallio, Pasi; Zhou, Quan; Korpinen, Juha; Koivo, Heikki N.

    2000-10-01

    This paper presents a computer-vision based position controller for a highly non-linear parallel piezohydraulic micromanipulator: in addition to its non-linear kinematics the micromanipulator experiences hysteresis and drive induced by piezoelectric actuators. The controller consists of a decoupling matrix that provides the decoupled translations (xyz) in the task frame and three Single Input Single Output (SISO) PI controllers for the translations. Position measurement is performed by a vision system that determines the x and y coordinates of the end- effector using a modified Hierarchical Chamfer Matching Algoritm (HCMA) and the z position using a depth-from-defocus method. Experiments show that the proposed controller is capable of serving the parallel micromanipulator with a sub-micron accuracy at a sampling rate of 18 Hz.

  3. Three-dimensional tracking with misalignment between display and control axes

    NASA Technical Reports Server (NTRS)

    Ellis, Stephen R.; Tyler, Mitchell; Kim, Won S.; Stark, Lawrence

    1991-01-01

    Consideration is given to experiments for examining 3D pursuit tracking when operators of teleoperation simulations are faced with misalignment between the display and control frames of reference. It is concluded that manual 3D pursuit tracking errors produced by display-control rotational misalignments have two linearly separable components: a purely visual component and a visual-motor component. Both components may independently influence the tracking performance. Human subjects can simultaneously adapt to a variety of display-control misalignments if position control during pursuit tracking is used with a simulation update rate of at least 30 Hz. This capability will enable trained operators to quickly adapt to changes in the position and orientation of viewing cameras during teleoperation and telemanipulation.

  4. Active control of elastic and rigid body response of a three-dimensional underwater structure

    SciTech Connect

    Suzuki, H.; Yoshida, K.; Watanabe, K.

    1995-02-01

    One key technology for the offshore development of the increasing water depth will be remotely operated installation and construction of flexible structure in the deep water or on the seabed. The flexibility comes from scale-up or weight reduction of the structure. Conventional operation from the sea surfaces is affected by the weather conditions, and, therefore, not so efficient. This paper presents basic research on active control of elastic response and rigid body motion of an underwater elastic structure toward the remotely operated installation technique. The numerical model of the dynamics of the structural model is formulated, and based on the numerical model the control is formulated. The formulated control is tested by computer simulations and model experiments. The structural model is propelled by thrusters and taken from initial position to another position, while the elastic responses are controlled by variable buoyancy-type actuators.

  5. Three-dimensional visualization and control of electronic warfare (EW) payloads

    NASA Astrophysics Data System (ADS)

    Kirsch, Patricia; Tremper, David; Cortesi, Roger

    2008-04-01

    The proliferation of unmanned vehicles carrying tactical payloads in the battle-space has accelerated the need for user-friendly visualization with graphical interfaces to provide remote command and control. Often these platforms and payloads receive their control functions from command centers located half a world away via satellite communications. Operators require situational awareness tools capable of graphically presenting the remote battlefield asset positions and collected sensor data. Often these systems use 2D software mapping tools in conjunction with video for real time situational awareness. The Special Projects Group (SPG) in the Tactical Electronic Warfare Division of the U.S. Naval Research Laboratory has been developing an operator control interface called the Jammer Control Station (JCS) to provide 3D battle-space visualization with built-in, remote EW payload command and control (C2) capabilities. The JCS interface presents the operator with graphic depictions of both the platforms' states and the RF environment. Text based messaging between the JCS and the EW payload reduces the impact of the system on the available bandwidth. This paper will discuss the use of the SIMDIS 3-D visualization tool as a real-time command and control interface for electronic warfare (EW) payloads.

  6. Feedback Control of the Wake of a Three-Dimensional Blunt Bluff Body

    NASA Astrophysics Data System (ADS)

    Flinois, Thibault; Morgans, Aimee

    2013-11-01

    When cars or trucks drive on motorways, more than two thirds of their fuel consumption is due to aerodynamic drag, a significant part of which is caused by the large scale separation that takes place near their trailing edge. We tackle this problem using Large Eddy Simulations and use feedback control of synthetic jets to reduce the losses associated with large-scale structures in the wake. The geometry is a long surface mounted block, whose leading edge is not modelled for computational efficiency and the structure of the unforced flow field around this body is similar to the flow over a surface mounted block or hump. Considering this flow field as a control system, the base pressure force was used as the system output and the input is a slot jet actuator located near the trailing edge. Using open-loop forcing, a form drag reduction of about 7.5% was obtained. Open-loop system identification also allowed a transfer function that models the system's response to actuation to be found. Finally, a set of feedback controllers were applied to the plant and their performance was analysed. These controllers successfully reduce the fluctuations in the near wake, with only a small control effort. However, more significant mean drag reductions are expected at higher Reynolds numbers. PhD Student, Imperial College London.

  7. A Three-Dimensional Object Orientation Detector Assisting People with Developmental Disabilities to Control Their Environmental Stimulation through Simple Occupational Activities with a Nintendo Wii Remote Controller

    ERIC Educational Resources Information Center

    Shih, Ching-Hsiang; Chang, Man-Ling; Mohua, Zhang

    2012-01-01

    This study evaluated whether two people with developmental disabilities would be able to actively perform simple occupational activities to control their preferred environmental stimulation using a Nintendo Wii Remote Controller with a newly developed three-dimensional object orientation detection program (TDOODP, i.e. a new software program,…

  8. A Three-Dimensional Object Orientation Detector Assisting People with Developmental Disabilities to Control Their Environmental Stimulation through Simple Occupational Activities with a Nintendo Wii Remote Controller

    ERIC Educational Resources Information Center

    Shih, Ching-Hsiang; Chang, Man-Ling; Mohua, Zhang

    2012-01-01

    This study evaluated whether two people with developmental disabilities would be able to actively perform simple occupational activities to control their preferred environmental stimulation using a Nintendo Wii Remote Controller with a newly developed three-dimensional object orientation detection program (TDOODP, i.e. a new software program,…

  9. Vital effects in coral skeletal composition display strict three-dimensional control

    USGS Publications Warehouse

    Meibom, A.; Yurimoto, H.; Cuif, J.-P.; Domart-Coulon, I.; Houlbreque, F.; Constantz, B.; Dauphin, Y.; Tambutte, E.; Tambutte, S.; Allemand, D.; Wooden, J.; Dunbar, R.

    2006-01-01

    Biological control over coral skeletal composition is poorly understood but critically important to paleoenvironmental reconstructions. We present microanalytical measurements of trace-element abundances as well as oxygen and carbon isotopic compositions of individual skeletal components in the zooxanthellate coral Colpophyllia sp. Our data show that centers of calcification (COC) have higher trace element concentrations and distinctly lighter isotopic compositions than the fibrous components of the skeleton. These observations necessitate that COC and the fibrous skeleton are precipitated by different mechanisms, which are controlled by specialized domains of the calicoblastic cell-layer. Biological processes control the composition of the skeleton even at the ultra-structure level. Copyright 2006 by the American Geophysical Union.

  10. Controlling three-dimensional vortices using multiple and moving external fields

    NASA Astrophysics Data System (ADS)

    Das, Nirmali Prabha; Dutta, Sumana

    2017-08-01

    Spirals or scroll wave activities in cardiac tissues are the cause of lethal arrhythmias. The external control of these waves is thus of prime interest to scientists and physicians. In this article, we demonstrate the spatial control of scroll waves by using external electric fields and thermal gradients in experiments with the Belousov-Zhabotinsky reaction. We show that a scroll ring can be made to trace cyclic trajectories under a rotating electric field. Application of a thermal gradient in addition to the electric field deflects the motion and changes the nature of the trajectory. Our experimental results are analyzed and corroborated by numerical simulations based on an excitable reaction diffusion model.

  11. Regional groundwater flow in mountainous terrain: Three-dimensional simulations of topographic and hydrogeologic controls

    USGS Publications Warehouse

    Gleeson, T.; Manning, A.H.

    2008-01-01

    This study uses numerical simulations to define the salient controls on regional groundwater flow in 3-D mountainous terrain by systematically varying topographic and hydrogeologic variables. Topography for idealized multiple-basin mountainous terrain is derived from geomatic data and literature values. Water table elevation, controlled by the ratio of recharge to hydraulic conductivity, largely controls the distribution of recharged water into local, regional, and perpendicular flow systems, perpendicular flow being perpendicular to the regional topographic gradient. Both the relative (%) and absolute (m 3/d) values of regional flow and perpendicular flow are examined. The relationship between regional flow and water table elevation is highly nonlinear. With lower water table elevations, relative and absolute regional flow dramatically increase and decrease, respectively, as the water table is lowered further. However, for higher water table elevations above the top of the headwater stream, changes in water table elevation have little effect on regional flow. Local flow predominates in high water table configurations, with regional and perpendicular flow <15% and <10%, respectively, of total recharge in the models tested. Both the relative and the maximum absolute regional flow are directly controlled by the degree of incision of the mountain drainage network; the elevation of mountain ridges is considerably less important. The percentage of the headwater stream with perennial streamflow is a potentially powerful indicator of regional flow in all water table configurations and may be a good indicator of the susceptibility of mountain groundwater systems to increased aridity. Copyright 2008 by the American Geophysical Union.

  12. Three-Dimensional Model for Electrospinning Processes in Controlled Gas Counterflow.

    PubMed

    Lauricella, Marco; Pisignano, Dario; Succi, Sauro

    2016-07-14

    We study the effects of a controlled gas flow on the dynamics of electrified jets in the electrospinning process. The main idea is to model the air drag effects of the gas flow by using a nonlinear Langevin-like approach. The model is employed to investigate the dynamics of electrified polymer jets at different conditions of air drag force, showing that a controlled gas counterflow can lead to a decrease of the average diameter of electrospun fibers, and potentially to an improvement of the quality of electrospun products. We probe the influence of air drag effects on the bending instabilities of the jet and on its angular fluctuations during the process. The insights provided by this study might prove useful for the design of future electrospinning experiments and polymer nanofiber materials.

  13. Three-Dimensional Model for Electrospinning Processes in Controlled Gas Counterflow

    PubMed Central

    2016-01-01

    We study the effects of a controlled gas flow on the dynamics of electrified jets in the electrospinning process. The main idea is to model the air drag effects of the gas flow by using a nonlinear Langevin-like approach. The model is employed to investigate the dynamics of electrified polymer jets at different conditions of air drag force, showing that a controlled gas counterflow can lead to a decrease of the average diameter of electrospun fibers, and potentially to an improvement of the quality of electrospun products. We probe the influence of air drag effects on the bending instabilities of the jet and on its angular fluctuations during the process. The insights provided by this study might prove useful for the design of future electrospinning experiments and polymer nanofiber materials. PMID:26859532

  14. Preparation and investigation of controlled-release glipizide novel oral device with three-dimensional printing.

    PubMed

    Li, Qijun; Wen, Haoyang; Jia, Danyang; Guan, Xiaoying; Pan, Hao; Yang, Yue; Yu, Shihui; Zhu, Zhihong; Xiang, Rongwu; Pan, Weisan

    2017-04-01

    The purpose of this study was to explore the feasibility of combining fused deposition modeling (FDM) 3D printing technology with hot melt extrusion (HME) to fabricate a novel controlled-release drug delivery device. Glipizide used in the treatment of diabetes was selected as model drug, and was successfully loaded into commercial polyvinyl alcohol(PVA) filaments by HME method. The drug-loaded filaments were printed through a dual-nozzle 3D printer, and finally formed a double-chamber device composed by a tablet embedded within a larger tablet (DuoTablet), each chamber contains different contents of glipizide. The drug-loaded 3D printed device was evaluated for drug release under in-vitro dissolution condition, and we found the release profile fit Korsmeyer-Peppas release kinetics. With the double-chamber design, it is feasible to design either controlled drug release or delayed drug release behavior by reasonably arranging the concentration distribution of the drug in the device. The characteristics of the external layer performed main influence on the release profile of the internal compartment such as lag-time or rate of release. The results of this study suggest the potential of 3D printing to fabricate controlled-release drug delivery system containing multiple drug concentration distributions via hot melt extrusion method and specialized design configurations.

  15. Vector theory of laser radiation scattering in an integrated optical waveguide with three-dimensional irregularities in the presence of noise

    SciTech Connect

    Egorov, Alexander A

    2004-08-31

    The vector theory of laser radiation scattering in an integrated optical waveguide with three-dimensional irregularities in the presence of noise is developed. The solution of the electrodynamic problem of laser radiation scattering in an irregular waveguide is obtained by the mode coupling technique using the perturbation theory. An approximate solution of the inhomogeneous three-dimensional wave equation is obtained by the method of Green's functions. The analytic formulas are derived for the radiation fields of propagating and evanescent modes. A physical interpretation is given for the obtained results. The role of noise as an independent depolarising factor (in addition to the classical one) during scattering of light is pointed out. (integrated optical waveguides and devices)

  16. A diffuser-based three-dimensional measurement of polarization-dependent scattering characteristics of optical films for 3D-display applications.

    PubMed

    Kim, Dae-Yeon; Seo, Jong-Wook

    2015-01-26

    We propose an accurate and easy-to-use three-dimensional measurement method using a diffuser plate to analyze the scattering characteristics of optical films. The far-field radiation pattern of light scattered by the optical film is obtained from the illuminance pattern created on the diffuser plate by the light. A mathematical model and calibration methods were described, and the results were compared with those obtained by a direct measurement using a luminance meter. The new method gave very precise three-dimensional polarization-dependent scattering characteristics of scattering polarizer films, and it can play an effective role in developing high performance polarization-selective screens for 3D display applications.

  17. Dynamics and Control of Three-Dimensional Perching Maneuver under Dynamic Stall Influence

    NASA Astrophysics Data System (ADS)

    Feroskhan, Mir Alikhan Bin Mohammad

    Perching is a type of aggressive maneuver performed by the class 'Aves' species to attain precision point landing with a generally short landing distance. Perching capability is desirable on unmanned aerial vehicles (UAVs) due to its efficient deceleration process that potentially expands the functionality and flight envelope of the aircraft. This dissertation extends the previous works on perching, which is mostly limited to two-dimensional (2D) cases, to its state-of-the-art threedimensional (3D) variety. This dissertation presents the aerodynamic modeling and optimization framework adopted to generate unprecedented variants of the 3D perching maneuver that include the sideslip perching trajectory, which ameliorates the existing 2D perching concept by eliminating the undesirable undershoot and reliance on gravity. The sideslip perching technique methodically utilizes the lateral and longitudinal drag mechanisms through consecutive phases of yawing and pitching-up motion. Since perching maneuver involves high rates of change in the angles of attack and large turn rates, introduction of three internal variables thus becomes necessary for addressing the influence of dynamic stall delay on the UAV's transient post-stall behavior. These variables are then integrated into a static nonlinear aerodynamic model, developed using empirical and analytical methods, and into an optimization framework that generates a trajectory of sideslip perching maneuver, acquiring over 70% velocity reduction. An impact study of the dynamic stall influence on the optimal perching trajectories suggests that consideration of dynamic stall delay is essential due to the significant discrepancies in the corresponding control inputs required. A comparative study between 2D and 3D perching is also conducted to examine the different drag mechanisms employed by 2D and 3D perching respectively. 3D perching is presented as a more efficient deceleration technique with respect to spatial costs and

  18. Three-dimensional morphology control during wet chemical synthesis of porous chromium oxide spheres.

    PubMed

    Chen, Lifang; Song, Zhi; Wang, Xue; Prikhodko, Sergey V; Hu, Juncheng; Kodambaka, Suneel; Richards, Ryan

    2009-09-01

    Controlling the morphological evolution in nanostructures is essential for improving their functionality, for example, in catalysis. Here, we demonstrate, using chromium oxide as a model system, that morphologies of functional binary oxide particles can be tailored by an efficient template-free synthetic approach. We construct a morphological "phase diagram" for chromium oxide spheres that shows the evolution of size and surface roughness as a function of the precursor and urea concentrations. It is notable that these chromium oxide spheres show an exceptional ability to remove azo-dye pollutant in water treatment. Thus, the porous chromium oxide spheres with very good dye absorptions are expected to be useful in alternative absorption technologies.

  19. Bioprinting three-dimensional cell-laden tissue constructs with controllable degradation

    PubMed Central

    Wu, Zhengjie; Su, Xin; Xu, Yuanyuan; Kong, Bin; Sun, Wei; Mi, Shengli

    2016-01-01

    Alginate hydrogel is a popular biologically inert material that is widely used in 3D bioprinting, especially in extrusion-based printing. However, the printed cells in this hydrogel could not degrade the surrounding alginate gel matrix, causing them to remain in a poorly proliferating and non-differentiating state. Here, we report a novel study of the 3D printing of human corneal epithelial cells (HCECs)/collagen/gelatin/alginate hydrogel incubated with a medium containing sodium citrate to obtain degradation-controllable cell-laden tissue constructs. The 3D-printed hydrogel network with interconnected channels and a macroporous structure was stable and achieved high cell viability (over 90%). By altering the mole ratio of sodium citrate/sodium alginate, the degradation time of the bioprinting constructs can be controlled. Cell proliferation and specific marker protein expression results also revealed that with the help of sodium citrate degradation, the printed HCECs showed a higher proliferation rate and greater cytokeratin 3(CK3) expression, indicating that this newly developed method may help to improve the alginate bioink system for the application of 3D bioprinting in tissue engineering. PMID:27091175

  20. Three-dimensional Moho topography in Italy: New constraints from receiver functions and controlled source seismology

    NASA Astrophysics Data System (ADS)

    di Stefano, R.; Bianchi, I.; Ciaccio, M. G.; Carrara, G.; Kissling, E.

    2011-09-01

    In complex tectonics regions, seismological, geophysical, and geodynamic modeling require accurate definition of the Moho geometry. Various active and passive seismic experiments performed in the central Mediterranean region revealed local information on the Moho depth, in some cases used to produce interpolated maps. In this paper, we present a new and original map of the 3-D Moho geometry obtained by integrating selected high-quality controlled source seismic and teleseismic receiver function data. The very small cell size makes the retrieved model suitable for detailed regional studies, crustal corrections in teleseismic tomography, advanced 3-D ray tracing in regional earthquake location, and local earthquake tomography. Our results show the geometry of three different Moho interfaces: the European, Adriatic-Ionian, and Tyrrhenian. The three distinct Moho are fashioned following the Alpine and Apennines subduction, collision, and back-arc spreading and show medium- to high-frequency topographic undulations reflecting the complexity of the geodynamic evolution.