WorldWideScience

Sample records for 3d nonlinear optical

  1. Numerical nonlinear complex geometrical optics algorithm for the 3D Calderón problem

    DEFF Research Database (Denmark)

    Delbary, Fabrice; Knudsen, Kim

    2014-01-01

    computer implementation of the full nonlinear algorithm is given. First a boundary integral equation is solved by a Nystrom method for the traces of the complex geometrical optics solutions, second the scattering transform is computed and inverted using fast Fourier transform, and finally a boundary value...

  2. Fast spatial beam shaping by acousto-optic diffraction for 3D non-linear microscopy.

    Science.gov (United States)

    Akemann, Walther; Léger, Jean-François; Ventalon, Cathie; Mathieu, Benjamin; Dieudonné, Stéphane; Bourdieu, Laurent

    2015-11-01

    Acousto-optic deflection (AOD) devices offer unprecedented fast control of the entire spatial structure of light beams, most notably their phase. AOD light modulation of ultra-short laser pulses, however, is not straightforward to implement because of intrinsic chromatic dispersion and non-stationarity of acousto-optic diffraction. While schemes exist to compensate chromatic dispersion, non-stationarity remains an obstacle. In this work we demonstrate an efficient AOD light modulator for stable phase modulation using time-locked generation of frequency-modulated acoustic waves at the full repetition rate of a high power laser pulse amplifier of 80 kHz. We establish the non-local relationship between the optical phase and the generating acoustic frequency function and verify the system for temporal stability, phase accuracy and generation of non-linear two-dimensional phase functions.

  3. Efficient Second Harmonic Generation in 3D Nonlinear Optical-Lattice-Like Cladding Waveguide Splitters by Femtosecond Laser Inscription.

    Science.gov (United States)

    Nie, Weijie; Jia, Yuechen; Vázquez de Aldana, Javier R; Chen, Feng

    2016-02-29

    Integrated photonic devices with beam splitting function are intriguing for a broad range of photonic applications. Through optical-lattice-like cladding waveguide structures fabricated by direct femtosecond laser writing, the light propagation can be engineered via the track-confined refractive index profiles, achieving tailored output beam distributions. In this work, we report on the fabrication of 3D laser-written optical-lattice-like structures in a nonlinear KTP crystal to implement 1 × 4 beam splitting. Second harmonic generation (SHG) of green light through these nonlinear waveguide beam splitter structures provides the capability for the compact visible laser emitting devices. With Type II phase matching of the fundamental wavelength (@ 1064 nm) to second harmonic waves (@ 532 nm), the frequency doubling has been achieved through this three-dimensional beam splitter. Under 1064-nm continuous-wave fundamental-wavelength pump beam, guided-wave SHG at 532 nm are measured with the maximum power of 0.65 mW and 0.48 mW for waveguide splitters (0.67 mW and 0.51 mW for corresponding straight channel waveguides), corresponding to a SH conversion efficiency of approximately ~14.3%/W and 13.9%/W (11.2%/W, 11.3%/W for corresponding straight channel waveguides), respectively. This work paves a way to fabricate compact integrated nonlinear photonic devices in a single chip with beam dividing functions.

  4. Ultra-fast 3D scanning and holographic illumination in non-linear microscopy using acousto-optic deflectors

    Science.gov (United States)

    Akemann, Walther; Ventalon, Cathie; Léger, Jean-François; Mathieu, Benjamin; Dieudonné, Stéphane; Blochet, Baptiste; Gigan, Sylvain; Bourdieu, Laurent

    2017-04-01

    Decoding of information in the brain requires the imaging of large neuronal networks using e.g. two-photon microscopy (TPM). Fast control of the focus in 3D can be achieved with phase shaping of the light beam using acoustooptic deflectors (AODs). However, beam shaping using AODs is not straightforward because of non-stationary of acousto-optic diffraction. Here, we demonstrated a new stable AOD-based phase modulator, which operates at a rate of up to about hundred kHz. It provides opportunity for 3D scanning in TPM with the possibility to correct aberrations independently for every focus position or to achieve refocusing of scattered photons in rapidly decorrelating tissues.

  5. High resolution 3D nonlinear integrated inversion

    Institute of Scientific and Technical Information of China (English)

    Li Yong; Wang Xuben; Li Zhirong; Li Qiong; Li Zhengwen

    2009-01-01

    The high resolution 3D nonlinear integrated inversion method is based on nonlinear theory. Under layer control, the log data from several wells (or all wells) in the study area and seismic trace data adjacent to the wells are input to a network with multiple inputs and outputs and are integratedly trained to obtain an adaptive weight function of the entire study area. Integrated nonlinear mapping relationships are built and updated by the lateral and vertical geologic variations of the reservoirs. Therefore, the inversion process and its inversion results can be constrained and controlled and a stable seismic inversion section with high resolution with velocity inversion, impedance inversion, and density inversion sections, can be gained. Good geologic effects have been obtained in model computation tests and real data processing, which verified that this method has high precision, good practicality, and can be used for quantitative reservoir analysis.

  6. 3-D nonlinear evolution of MHD instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, G.; Hicks, H. R.; Wooten, J. W.

    1977-03-01

    The nonlinear evolution of ideal MHD internal instabilities is investigated in straight cylindrical geometry by means of a 3-D initial-value computer code. These instabilities are characterized by pairs of velocity vortex cells rolling off each other and helically twisted down the plasma column. The cells persist until the poloidal velocity saturates at a few tenths of the Alfven velocity. The nonlinear phase is characterized by convection around these essentially fixed vortex cells. For example, the initially centrally peaked temperature profile is convected out and around to form an annulus of high temperature surrounding a small region of lower temperature. Weak, centrally localized instabilities do not alter the edge of the plasma. Strong, large-scale instabilities, resulting from a stronger longitudinal equilibrium current, drive the plasma against the wall. After three examples of instability are analyzed in detail, the numerical methods and their verification are discussed.

  7. 3D simulation for solitons used in optical fibers

    Science.gov (United States)

    Vasile, F.; Tebeica, C. M.; Schiopu, P.; Vladescu, M.

    2016-12-01

    In this paper is described 3D simulation for solitions used in optical fibers. In the scientific works is started from nonlinear propagation equation and the solitons represents its solutions. This paper presents the simulation of the fundamental soliton in 3D together with simulation of the second order soliton in 3D. These simulations help in the study of the optical fibers for long distances and in the interactions between the solitons. This study helps the understanding of the nonlinear propagation equation and for nonlinear waves. These 3D simulations are obtained using MATLAB programming language, and we can observe fundamental difference between the soliton and the second order/higher order soliton and in their evolution.

  8. Nonlinear optics

    CERN Document Server

    Bloembergen, Nicolaas

    1996-01-01

    Nicolaas Bloembergen, recipient of the Nobel Prize for Physics (1981), wrote Nonlinear Optics in 1964, when the field of nonlinear optics was only three years old. The available literature has since grown by at least three orders of magnitude.The vitality of Nonlinear Optics is evident from the still-growing number of scientists and engineers engaged in the study of new nonlinear phenomena and in the development of new nonlinear devices in the field of opto-electronics. This monograph should be helpful in providing a historical introduction and a general background of basic ideas both for expe

  9. Nonlinear optics

    CERN Document Server

    Boyd, Robert W

    2013-01-01

    Nonlinear Optics is an advanced textbook for courses dealing with nonlinear optics, quantum electronics, laser physics, contemporary and quantum optics, and electrooptics. Its pedagogical emphasis is on fundamentals rather than particular, transitory applications. As a result, this textbook will have lasting appeal to a wide audience of electrical engineering, physics, and optics students, as well as those in related fields such as materials science and chemistry.Key Features* The origin of optical nonlinearities, including dependence on the polarization of light* A detailed treatment of the q

  10. FIT3D: Fitting optical spectra

    Science.gov (United States)

    Sánchez, S. F.; Pérez, E.; Sánchez-Blázquez, P.; González, J. J.; Rosales-Ortega, F. F.; Cano-Díaz, M.; López-Cobá, C.; Marino, R. A.; Gil de Paz, A.; Mollá, M.; López-Sánchez, A. R.; Ascasibar, Y.; Barrera-Ballesteros, J.

    2016-09-01

    FIT3D fits optical spectra to deblend the underlying stellar population and the ionized gas, and extract physical information from each component. FIT3D is focused on the analysis of Integral Field Spectroscopy data, but is not restricted to it, and is the basis of Pipe3D, a pipeline used in the analysis of datasets like CALIFA, MaNGA, and SAMI. It can run iteratively or in an automatic way to derive the parameters of a large set of spectra.

  11. 3D nanopillar optical antenna photodetectors.

    Science.gov (United States)

    Senanayake, Pradeep; Hung, Chung-Hong; Shapiro, Joshua; Scofield, Adam; Lin, Andrew; Williams, Benjamin S; Huffaker, Diana L

    2012-11-05

    We demonstrate 3D surface plasmon photoresponse in nanopillar arrays resulting in enhanced responsivity due to both Localized Surface Plasmon Resonances (LSPRs) and Surface Plasmon Polariton Bloch Waves (SPP-BWs). The LSPRs are excited due to a partial gold shell coating the nanopillar which acts as a 3D Nanopillar Optical Antenna (NOA) in focusing light into the nanopillar. Angular photoresponse measurements show that SPP-BWs can be spectrally coincident with LSPRs to result in a x2 enhancement in responsivity at 1180 nm. Full-wave Finite Difference Time Domain (FDTD) simulations substantiate both the spatial and spectral coupling of the SPP-BW / LSPR for enhanced absorption and the nature of the LSPR. Geometrical control of the 3D NOA and the self-aligned metal hole lattice allows the hybridization of both localized and propagating surface plasmon modes for enhanced absorption. Hybridized plasmonic modes opens up new avenues in optical antenna design in nanoscale photodetectors.

  12. 3D integral imaging with optical processing

    Science.gov (United States)

    Martínez-Corral, Manuel; Martínez-Cuenca, Raúl; Saavedra, Genaro; Javidi, Bahram

    2008-04-01

    Integral imaging (InI) systems are imaging devices that provide auto-stereoscopic images of 3D intensity objects. Since the birth of this new technology, InI systems have faced satisfactorily many of their initial drawbacks. Basically, two kind of procedures have been used: digital and optical procedures. The "3D Imaging and Display Group" at the University of Valencia, with the essential collaboration of Prof. Javidi, has centered its efforts in the 3D InI with optical processing. Among other achievements, our Group has proposed the annular amplitude modulation for enlargement of the depth of field, dynamic focusing for reduction of the facet-braiding effect, or the TRES and MATRES devices to enlarge the viewing angle.

  13. Multiplane 3D superresolution optical fluctuation imaging

    CERN Document Server

    Geissbuehler, Stefan; Godinat, Aurélien; Bocchio, Noelia L; Dubikovskaya, Elena A; Lasser, Theo; Leutenegger, Marcel

    2013-01-01

    By switching fluorophores on and off in either a deterministic or a stochastic manner, superresolution microscopy has enabled the imaging of biological structures at resolutions well beyond the diffraction limit. Superresolution 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 conventional widefield microscope. So far, three-dimensional (3D) SOFI has only been demonstrated by sequential imaging of multiple depth positions. Here we introduce a versatile imaging scheme which allows for the simultaneous acquisition of multiple focal planes. Using 3D cross-cumulants, we show that the depth sampling can be increased. Consequently, the simultaneous acquisition of multiple focal planes reduces the acquisition time and hence the photo-bleaching of fluorescent markers. We demonstrate multiplane 3D SOFI by imaging the mitochondria network in fixed ...

  14. Multi-resolution optical 3D sensor

    Science.gov (United States)

    Kühmstedt, Peter; Heinze, Matthias; Schmidt, Ingo; Breitbarth, Martin; Notni, Gunther

    2007-06-01

    A new multi resolution self calibrating optical 3D measurement system using fringe projection technique named "kolibri FLEX multi" will be presented. It can be utilised to acquire the all around shape of small to medium objects, simultaneously. The basic measurement principle is the phasogrammetric approach /1,2,3/ in combination with the method of virtual landmarks for the merging of the 3D single views. The system consists in minimum of two fringe projection sensors. The sensors are mounted on a rotation stage illuminating the object from different directions. The measurement fields of the sensors can be chosen different, here as an example 40mm and 180mm in diameter. In the measurement the object can be scanned at the same time with these two resolutions. Using the method of virtual landmarks both point clouds are calculated within the same world coordinate system resulting in a common 3D-point cloud. The final point cloud includes the overview of the object with low point density (wide field) and a region with high point density (focussed view) at the same time. The advantage of the new method is the possibility to measure with different resolutions at the same object region without any mechanical changes in the system or data post processing. Typical parameters of the system are: the measurement time is 2min for 12 images and the measurement accuracy is below 3μm up to 10 μm. The flexibility makes the measurement system useful for a wide range of applications such as quality control, rapid prototyping, design and CAD/CAM which will be shown in the paper.

  15. Similarities Derived from 3-D Nonlinear Psychophysics: Variance Distributions.

    Science.gov (United States)

    Gregson, Robert A. M.

    1994-01-01

    The derivation of the variance of similarity judgments is made from the 3-D process in nonlinear psychophysics. The idea of separability of dimensions in metric space theories of similarity is replaced by one parameter that represents the degree of a form of interdimensional cross-sampling. (SLD)

  16. Spatial 3-D nonlinear calibration technique for PSD

    Science.gov (United States)

    Guo, Lifeng; Zhang, Guoxiong; Zheng, Qi; Gong, Qiang; Liu, Wenyao

    2006-11-01

    A 3-D nonlinear calibration technique for Position sensitive detector (PSD) in long distance laser collimating measurement is proposed. An automatic calibration system was developed to measure the nonlinearity of a 2-D PSD in 3-D space. It is mainly composed of a high accurate 2-D motorized translational stage, a high precision distance measuring device, and a computer-based data acquisition and control system. With the aid of the calibration system, the nonlinear characteristic of 2-D PSD is checked in a long collimating distance up to 78 meters. The calibration experiment was carried out for a series of distance, e.g. every 15 meters. The results showed that the nonlinearity of 2-D PSD is different evidently when the PSD element is at different distance from the laser head. One calculating method is defined to evaluate the nonlinear errors. The spatial 3-D mapping relationship between the actual displacements of the incident light and the coordinates of 2-D PSD outputs is established using a multilayer feedforward neural network.

  17. Handbook of 3D machine vision optical metrology and imaging

    CERN Document Server

    Zhang, Song

    2013-01-01

    With the ongoing release of 3D movies and the emergence of 3D TVs, 3D imaging technologies have penetrated our daily lives. Yet choosing from the numerous 3D vision methods available can be frustrating for scientists and engineers, especially without a comprehensive resource to consult. Filling this gap, Handbook of 3D Machine Vision: Optical Metrology and Imaging gives an extensive, in-depth look at the most popular 3D imaging techniques. It focuses on noninvasive, noncontact optical methods (optical metrology and imaging). The handbook begins with the well-studied method of stereo vision and

  18. Utilization of multiple frequencies in 3D nonlinear microwave imaging

    DEFF Research Database (Denmark)

    Jensen, Peter Damsgaard; Rubæk, Tonny; Mohr, Johan Jacob

    2012-01-01

    The use of multiple frequencies in a nonlinear microwave algorithm is considered. Using multiple frequencies allows for obtaining the improved resolution available at the higher frequencies while retaining the regularizing effects of the lower frequencies. However, a number of different challenges...... at lower frequencies are used as starting guesses for reconstructions at higher frequencies. The performance is illustrated using simulated 2-D data and data obtained with the 3-D DTU microwave imaging system....

  19. The 3D solitons and vortices in 3D discrete monatomic lattices with cubic and quartic nonlinearity

    Institute of Scientific and Technical Information of China (English)

    Xu Quan; Tian Qiang

    2006-01-01

    By virtue of the method of multiple-scale and the quasi-discreteness approach, we have discussed the nonlinear vibration equation of a 3D discrete monatomic lattice with its nearest-neighbours interaction. The 3D simple cubic lattices have the same localized modes as a ID discrete monatomic chain with cubic and quartic nonlinearity. The nonlinear vibration in the 3D simple cubic lattice has 3D distorted solitons and 3D envelop solitons in the direction of kx = ky = kz = k and k =±π/6a0 in the Brillouin zone, as well as has 3D vortices in the direction of kx = ky = kz = k and k =±π/a0 in the Brillouin zone.

  20. Advances in nonlinear optics

    CERN Document Server

    Chen, Xianfeng; Zeng, Heping; Guo, Qi; She, Weilong

    2015-01-01

    This book presents an overview of the state of the art of nonlinear optics from weak light nonlinear optics, ultrafast nonlinear optics to electro-optical theory and applications. Topics range from the fundamental studies of the interaction between matter and radiation to the development of devices, components, and systems of tremendous commercial interest for widespread applications in optical telecommunications, medicine, and biotechnology.

  1. Manufacturing: 3D printed micro-optics

    Science.gov (United States)

    Juodkazis, Saulius

    2016-08-01

    Uncompromised performance of micro-optical compound lenses has been achieved by high-fidelity shape definition during two-photon absorption microfabrication. The lenses have been made directly onto image sensors and even onto the tip of an optic fibre.

  2. Optical experiments on 3D photonic crystals

    NARCIS (Netherlands)

    Koenderink, F.; Vos, W.

    2003-01-01

    Photonic crystals are optical materials that have an intricate structure with length scales of the order of the wavelength of light. The flow of photons is controlled in a manner analogous to how electrons propagate through semiconductor crystals, i.e., by Bragg diffraction and the formation of band

  3. Two excellent phase-matchable infrared nonlinear optical materials based on 3D diamond-like frameworks: RbGaSn2Se6 and RbInSn2Se6.

    Science.gov (United States)

    Lin, Hua; Chen, Hong; Zheng, Yu-Jun; Yu, Ju-Song; Wu, Xin-Tao; Wu, Li-Ming

    2017-06-28

    Mid- and far-infrared (MFIR) nonlinear optical (NLO) crystals with excellent performances are critical to laser frequency-conversion technology. However, the current commercial MFIR NLO crystals, including AgGaS2 (AGS), AgGaSe2 and ZnGeP2, suffer from certain intrinsic drawbacks and cannot achieve a good balance between large second-harmonic generation (SHG) efficiency and high laser-induced damage thresholds (LIDTs). Herein, we report two new phase-matchable MFIR NLO chalcogenides, specifically RbXSn2Se6 (X = Ga, In), which were successfully synthesized by high-temperature solid-state reactions. The remarkable structural feature of these materials was their 3D diamond-like framework (DLF) stacked by M3Se9 (M = X/Sn) asymmetric building units of vertex-sharing MSe4 tetrahedra along the c axis. Significantly, both of the materials showed the excellent NLO performances with the desired balance between their large SHG efficiencies (4.2 and 4.8 × benchmark AGS) and large LIDTs (8.9 and 8.1 × benchmark AGS), demonstrating that the title compounds meet the crucial conditions as promising MFIR NLO candidates. Furthermore, the crystal structures, synthesis, and theoretical analysis, as well as optical properties are presented herein.

  4. A 3D printed electromagnetic nonlinear vibration energy harvester

    Science.gov (United States)

    Constantinou, P.; Roy, S.

    2016-09-01

    A 3D printed electromagnetic vibration energy harvester is presented. The motion of the device is in-plane with the excitation vibrations, and this is enabled through the exploitation of a leaf isosceles trapezoidal flexural pivot topology. This topology is ideally suited for systems requiring restricted out-of-plane motion and benefits from being fabricated monolithically. This is achieved by 3D printing the topology with materials having a low flexural modulus. The presented system has a nonlinear softening spring response, as a result of designed magnetic force interactions. A discussion of fatigue performance is presented and it is suggested that whilst fabricating, the raster of the suspension element is printed perpendicular to the flexural direction and that the experienced stress is as low as possible during operation, to ensure longevity. A demonstrated power of ˜25 μW at 0.1 g is achieved and 2.9 mW is demonstrated at 1 g. The corresponding bandwidths reach up-to 4.5 Hz. The system’s corresponding power density of ˜0.48 mW cm-3 and normalised power integral density of 11.9 kg m-3 (at 1 g) are comparable to other in-plane systems found in the literature.

  5. High-resolution nonlinear ellipse rotation measurements for 3D microscopy

    Science.gov (United States)

    Miguez, M. L.; Barbano, E. C.; Coura, J. A.; Zilio, S. C.; Misoguti, L.

    2015-03-01

    Nonlinear optical effects have been widely explored for microscopy due to the possibility of three-dimension (3D) image acquisition. Harmonic generation and nonlinear absorption, for instance, were used for this purpose. Each nonlinear effect has its own characteristic, complexity, type of contrast, advantage and disadvantage, etc. Recently, we developed a new simple and sensitive method for measuring nonlinear ellipse rotation (NER) using a dual-phase lock-in amplifier, which could be successfully applied for measuring local nonlinearity distribution on a sample and, consequently, the image acquisition. The NER is a particular refractive nonlinear effect which appears when strong elliptical polarized laser beam propagates along one nonlinear material. It is type of refractive Kerr nonlinearity similar to self-focalization responsible for the signal in the Z-scan technique. The self-focalization is one of the most important refractive effects, but it cannot be used for image acquisition. On the other hand, NER does. Furthermore, such refractive nonlinearities signal can be very strong and serves as a new contrast for nonlinear microscopy.

  6. Three-Dimensional Optical Coherence Tomography (3D OCT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Applied Science Innovations, Inc. proposes to develop a new tool of 3D optical coherence tomography (OCT) for cellular level imaging at video frame rates and...

  7. Three-Dimensional Optical Coherence Tomography (3D OCT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Applied Science Innovations, Inc. proposes a new tool of 3D optical coherence tomography (OCT) for cellular level imaging at video frame rates and dramatically...

  8. A 3D Optical Metamaterial Made by Self-Assembly

    KAUST Repository

    Vignolini, Silvia

    2011-10-24

    Optical metamaterials have unusual optical characteristics that arise from their periodic nanostructure. Their manufacture requires the assembly of 3D architectures with structure control on the 10-nm length scale. Such a 3D optical metamaterial, based on the replication of a self-assembled block copolymer into gold, is demonstrated. The resulting gold replica has a feature size that is two orders of magnitude smaller than the wavelength of visible light. Its optical signature reveals an archetypal Pendry wire metamaterial with linear and circular dichroism. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Parallel Processor for 3D Recovery from Optical Flow

    Directory of Open Access Journals (Sweden)

    Jose Hugo Barron-Zambrano

    2009-01-01

    Full Text Available 3D recovery from motion has received a major effort in computer vision systems in the recent years. The main problem lies in the number of operations and memory accesses to be performed by the majority of the existing techniques when translated to hardware or software implementations. This paper proposes a parallel processor for 3D recovery from optical flow. Its main feature is the maximum reuse of data and the low number of clock cycles to calculate the optical flow, along with the precision with which 3D recovery is achieved. The results of the proposed architecture as well as those from processor synthesis are presented.

  10. Organic nonlinear optical materials

    Science.gov (United States)

    Umegaki, S.

    1987-01-01

    Recently, it became clear that organic compounds with delocalized pi electrons show a great nonlinear optical response. Especially, secondary nonlinear optical constants of more than 2 digits were often seen in the molecular level compared to the existing inorganic crystals such as LiNbO3. The crystallization was continuously tried. Organic nonlinear optical crystals have a new future as materials for use in the applied physics such as photomodulation, optical frequency transformation, opto-bistabilization, and phase conjugation optics. Organic nonlinear optical materials, e.g., urea, O2NC6H4NH2, I, II, are reviewed with 50 references.

  11. An Optically Controlled 3D Cell Culturing System

    Directory of Open Access Journals (Sweden)

    Kelly S. Ishii

    2011-01-01

    Full Text Available A novel 3D cell culture system was developed and tested. The cell culture device consists of a microfluidic chamber on an optically absorbing substrate. Cells are suspended in a thermoresponsive hydrogel solution, and optical patterns are utilized to heat the solution, producing localized hydrogel formation around cells of interest. The hydrogel traps only the desired cells in place while also serving as a biocompatible scaffold for supporting the cultivation of cells in 3D. This is demonstrated with the trapping of MDCK II and HeLa cells. The light intensity from the optically induced hydrogel formation does not significantly affect cell viability.

  12. Research of 3D display using anamorphic optics

    Science.gov (United States)

    Matsumoto, Kenji; Honda, Toshio

    1997-05-01

    This paper describes the auto-stereoscopic display which can reconstruct more reality and viewer friendly 3-D image by increasing the number of parallaxes and giving motion parallax horizontally. It is difficult to increase number of parallaxes to give motion parallax to the 3-D image without reducing the resolution, because the resolution of display device is insufficient. The magnification and the image formation position can be selected independently in horizontal direction and the vertical direction by projecting between the display device and the 3-D image with the anamorphic optics. The anamorphic optics is an optics system with different magnification in horizontal direction and the vertical direction. It consists of the combination of cylindrical lenses with different focal length. By using this optics, even if we use a dynamic display such as liquid crystal display (LCD), it is possible to display the realistic 3-D image having motion parallax. Motion parallax is obtained by assuming width of the single parallax at the viewing position to be about the same size as the pupil diameter of viewer. In addition, because the focus depth of the 3-D image is deep in this method, conflict of accommodation and convergence is small, and natural 3-D image can be displayed.

  13. Optical-CT imaging of complex 3D dose distributions

    Science.gov (United States)

    Oldham, Mark; Kim, Leonard; Hugo, Geoffrey

    2005-04-01

    The limitations of conventional dosimeters restrict the comprehensiveness of verification that can be performed for advanced radiation treatments presenting an immediate and substantial problem for clinics attempting to implement these techniques. In essence, the rapid advances in the technology of radiation delivery have not been paralleled by corresponding advances in the ability to verify these treatments. Optical-CT gel-dosimetry is a relatively new technique with potential to address this imbalance by providing high resolution 3D dose maps in polymer and radiochromic gel dosimeters. We have constructed a 1st generation optical-CT scanner capable of high resolution 3D dosimetry and applied it to a number of simple and increasingly complex dose distributions including intensity-modulated-radiation-therapy (IMRT). Prior to application to IMRT, the robustness of optical-CT gel dosimetry was investigated on geometry and variable attenuation phantoms. Physical techniques and image processing methods were developed to minimize deleterious effects of refraction, reflection, and scattered laser light. Here we present results of investigations into achieving accurate high-resolution 3D dosimetry with optical-CT, and show clinical examples of 3D IMRT dosimetry verification. In conclusion, optical-CT gel dosimetry can provide high resolution 3D dose maps that greatly facilitate comprehensive verification of complex 3D radiation treatments. Good agreement was observed at high dose levels (>50%) between planned and measured dose distributions. Some systematic discrepancies were observed however (rms discrepancy 3% at high dose levels) indicating further work is required to eliminate confounding factors presently compromising the accuracy of optical-CT 3D gel-dosimetry.

  14. Progresses in 3D integral imaging with optical processing

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Corral, Manuel; Martinez-Cuenca, Raul; Saavedra, Genaro; Navarro, Hector; Pons, Amparo [Department of Optics. University of Valencia. Calle Doctor Moliner 50, E46 100, Burjassot (Spain); Javidi, Bahram [Electrical and Computer Engineering Department, University of Connecticut, Storrs, CT 06269-1157 (United States)], E-mail: manuel.martinez@uv.es

    2008-11-01

    Integral imaging is a promising technique for the acquisition and auto-stereoscopic display of 3D scenes with full parallax and without the need of any additional devices like special glasses. First suggested by Lippmann in the beginning of the 20th century, integral imaging is based in the intersection of ray cones emitted by a collection of 2D elemental images which store the 3D information of the scene. This paper is devoted to the study, from the ray optics point of view, of the optical effects and interaction with the observer of integral imaging systems.

  15. Nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind P

    2001-01-01

    The Optical Society of America (OSA) and SPIE - The International Society for Optical Engineering have awarded Govind Agrawal with an honorable mention for the Joseph W. Goodman Book Writing Award for his work on Nonlinear Fiber Optics, 3rd edition.Nonlinear Fiber Optics, 3rd Edition, provides a comprehensive and up-to-date account of the nonlinear phenomena occurring inside optical fibers. It retains most of the material that appeared in the first edition, with the exception of Chapter 6, which is now devoted to the polarization effects relevant for light propagation in optical

  16. Nonlinear optical systems

    CERN Document Server

    Lugiato, Luigi; Brambilla, Massimo

    2015-01-01

    Guiding graduate students and researchers through the complex world of laser physics and nonlinear optics, this book provides an in-depth exploration of the dynamics of lasers and other relevant optical systems, under the umbrella of a unitary spatio-temporal vision. Adopting a balanced approach, the book covers traditional as well as special topics in laser physics, quantum electronics and nonlinear optics, treating them from the viewpoint of nonlinear dynamical systems. These include laser emission, frequency generation, solitons, optically bistable systems, pulsations and chaos and optical pattern formation. It also provides a coherent and up-to-date treatment of the hierarchy of nonlinear optical models and of the rich variety of phenomena they describe, helping readers to understand the limits of validity of each model and the connections among the phenomena. It is ideal for graduate students and researchers in nonlinear optics, quantum electronics, laser physics and photonics.

  17. Optical fabrication of lightweighted 3D printed mirrors

    Science.gov (United States)

    Herzog, Harrison; Segal, Jacob; Smith, Jeremy; Bates, Richard; Calis, Jacob; De La Torre, Alyssa; Kim, Dae Wook; Mici, Joni; Mireles, Jorge; Stubbs, David M.; Wicker, Ryan

    2015-09-01

    Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM) 3D printing technologies were utilized to create lightweight, optical grade mirrors out of AlSi10Mg aluminum and Ti6Al4V titanium alloys at the University of Arizona in Tucson. The mirror prototypes were polished to meet the λ/20 RMS and λ/4 P-V surface figure requirements. The intent of this project was to design topologically optimized mirrors that had a high specific stiffness and low surface displacement. Two models were designed using Altair Inspire software, and the mirrors had to endure the polishing process with the necessary stiffness to eliminate print-through. Mitigating porosity of the 3D printed mirror blanks was a challenge in the face of reconciling new printing technologies with traditional optical polishing methods. The prototypes underwent Hot Isostatic Press (HIP) and heat treatment to improve density, eliminate porosity, and relieve internal stresses. Metal 3D printing allows for nearly unlimited topological constraints on design and virtually eliminates the need for a machine shop when creating an optical quality mirror. This research can lead to an increase in mirror mounting support complexity in the manufacturing of lightweight mirrors and improve overall process efficiency. The project aspired to have many future applications of light weighted 3D printed mirrors, such as spaceflight. This paper covers the design/fab/polish/test of 3D printed mirrors, thermal/structural finite element analysis, and results.

  18. 3D optical manipulation of a single electron spin

    CERN Document Server

    Geiselmann, Michael; Renger, Jan; Say, Jana M; Brown, Louise J; de Abajo, F Javier García; Koppens, Frank; Quidant, Romain

    2013-01-01

    Nitrogen vacancy (NV) centers in diamond are promising elemental blocks for quantum optics [1, 2], spin-based quantum information processing [3, 4], and high-resolution sensing [5-13]. Yet, fully exploiting these capabilities of single NV centers requires strategies to accurately manipulate them. Here, we use optical tweezers as a tool to achieve deterministic trapping and 3D spatial manipulation of individual nano-diamonds hosting a single NV spin. Remarkably, we find the NV axis is nearly fixed inside the trap and can be controlled in-situ, by adjusting the polarization of the trapping light. By combining this unique spatial and angular control with coherent manipulation of the NV spin and fluorescent lifetime measurements near an integrated photonic system, we prove optically trapped NV center as a novel route for both 3D vectorial magnetometry and sensing of the local density of optical states.

  19. Distributed nonlinear optical response

    DEFF Research Database (Denmark)

    Nikolov, Nikola Ivanov

    2005-01-01

    The purpose of the research presented here is to investigate basic physical properties in nonlinear optical materials with delayed or nonlocal nonlinearity. Soliton propagation, spectral broadening and the influence of the nonlocality or delay of the nonlinearity are the main focusses in the work...

  20. 3D manipulation with a scanning near field optical nanotweezers

    CERN Document Server

    Berthelot, J; Juan, M L; Kreuzer, M P; Renger, J; Quidant, R

    2013-01-01

    Recent advances in Nanotechnologies have prompted the need for tools to accurately and non-invasively manipulate individual nano-objects. Among possible strategies, optical forces have been foreseen to provide researchers with nano-optical tweezers capable to trap a specimen and move it in 3D. In practice though, the combination of weak optical forces involved and photothermal issues have thus far prevented their experimental realization. Here, we demonstrate first 3D optical manipulation of single 50 nm dielectric objects with near field nano-tweezers. The nano-optical trap is built by engineering a bowtie plasmonic aperture at the extremity of a tapered metal-coated optical fiber. Both the trapping operation and monitoring are performed through the optical fiber making these nano-tweezers totally autonomous and free of bulky optical elements. The achieved trapping performances allow for the trapped specimen to be moved over tens of micrometers during several minutes with very low in-trap intensities. This n...

  1. Nonlinear optical materials.

    Science.gov (United States)

    Eaton, D F

    1991-07-19

    The current state of materials development in nonlinear optics is summarized, and the promise of these materials is critically evaluated. Properties and important materials constants of current commercial materials and of new, promising, inorganic and organic molecular and polymeric materials with potential in second- and third-order nonlinear optical applications are presented.

  2. Advanced optical 3D scanners using DMD technology

    Science.gov (United States)

    Muenstermann, P.; Godding, R.; Hermstein, M.

    2017-02-01

    Optical 3D measurement techniques are state-of-the-art for highly precise, non-contact surface scanners - not only in industrial development, but also in near-production and even in-line configurations. The need for automated systems with very high accuracy and clear implementation of national precision standards is growing extremely due to expanding international quality guidelines, increasing production transparency and new concepts related to the demands of the fourth industrial revolution. The presentation gives an overview about the present technical concepts for optical 3D scanners and their benefit for customers and various different applications - not only in quality control, but also in design centers or in medical applications. The advantages of DMD-based systems will be discussed and compared to other approaches. Looking at today's 3D scanner market, there is a confusing amount of solutions varying from lowprice solutions to high end systems. Many of them are linked to a very special target group or to special applications. The article will clarify the differences of the approaches and will discuss some key features which are necessary to render optical measurement systems suitable for industrial environments. The paper will be completed by examples for DMDbased systems, e. g. RGB true-color systems with very high accuracy like the StereoScan neo of AICON 3D Systems. Typical applications and the benefits for customers using such systems are described.

  3. Automatic respiration tracking for radiotherapy using optical 3D camera

    Science.gov (United States)

    Li, Tuotuo; Geng, Jason; Li, Shidong

    2013-03-01

    Rapid optical three-dimensional (O3D) imaging systems provide accurate digitized 3D surface data in real-time, with no patient contact nor radiation. The accurate 3D surface images offer crucial information in image-guided radiation therapy (IGRT) treatments for accurate patient repositioning and respiration management. However, applications of O3D imaging techniques to image-guided radiotherapy have been clinically challenged by body deformation, pathological and anatomical variations among individual patients, extremely high dimensionality of the 3D surface data, and irregular respiration motion. In existing clinical radiation therapy (RT) procedures target displacements are caused by (1) inter-fractional anatomy changes due to weight, swell, food/water intake; (2) intra-fractional variations from anatomy changes within any treatment session due to voluntary/involuntary physiologic processes (e.g. respiration, muscle relaxation); (3) patient setup misalignment in daily reposition due to user errors; and (4) changes of marker or positioning device, etc. Presently, viable solution is lacking for in-vivo tracking of target motion and anatomy changes during the beam-on time without exposing patient with additional ionized radiation or high magnet field. Current O3D-guided radiotherapy systems relay on selected points or areas in the 3D surface to track surface motion. The configuration of the marks or areas may change with time that makes it inconsistent in quantifying and interpreting the respiration patterns. To meet the challenge of performing real-time respiration tracking using O3D imaging technology in IGRT, we propose a new approach to automatic respiration motion analysis based on linear dimensionality reduction technique based on PCA (principle component analysis). Optical 3D image sequence is decomposed with principle component analysis into a limited number of independent (orthogonal) motion patterns (a low dimension eigen-space span by eigen-vectors). New

  4. Nonlinear optics and photonics

    CERN Document Server

    He, Guang S

    2015-01-01

    This book provides a comprehensive presentation on most of the major topics in nonlinear optics and photonics, with equal emphasis on principles, experiments, techniques, and applications. It covers many major new topics including optical solitons, multi-photon effects, nonlinear photoelectric effects, fast and slow light , and Terahertz photonics. Chapters 1-10 present the fundamentals of modern nonlinear optics, and could be used as a textbook with problems provided at the end of each chapter. Chapters 11-17 cover the more advanced topics of techniques and applications of nonlinear optics and photonics, serving as a highly informative reference for researchers and experts working in related areas. There are also 16 pages of color photographs to illustrate the visual appearances of some typical nonlinear optical effects and phenomena. The book could be adopted as a textbook for both undergraduates and graduate students, and serve as a useful reference work for researchers and experts in the fields of physics...

  5. Implementation of 3D Optical Scanning Technology for Automotive Applications

    Directory of Open Access Journals (Sweden)

    Abdil Kuş

    2009-03-01

    Full Text Available Reverse engineering (RE is a powerful tool for generating a CAD model from the 3D scan data of a physical part that lacks documentation or has changed from the original CAD design of the part. The process of digitizing a part and creating a CAD model from 3D scan data is less time consuming and provides greater accuracy than manually measuring the part and designing the part from scratch in CAD. 3D optical scanning technology is one of the measurement methods which have evolved over the last few years and it is used in a wide range of areas from industrial applications to art and cultural heritage. It is also used extensively in the automotive industry for applications such as part inspections, scanning of tools without CAD definition, scanning the casting for definition of the stock (i.e. the amount of material to be removed from the surface of the castings model for CAM programs and reverse engineering. In this study two scanning experiments of automotive applications are illustrated. The first one examines the processes from scanning to re-manufacturing the damaged sheet metal cutting die, using a 3D scanning technique and the second study compares the scanned point clouds data to 3D CAD data for inspection purposes. Furthermore, the deviations of the part holes are determined by using different lenses and scanning parameters.

  6. Continuous Optical 3D Printing of Green Aliphatic Polyurethanes.

    Science.gov (United States)

    Pyo, Sang-Hyun; Wang, Pengrui; Hwang, Henry H; Zhu, Wei; Warner, John; Chen, Shaochen

    2017-01-11

    Photosensitive diurethanes were prepared from a green chemistry synthesis pathway based on methacrylate-functionalized six-membered cyclic carbonate and biogenic amines. A continuous optical 3D printing method for the diurethanes was developed to create user-defined gradient stiffness and smooth complex surface microstructures in seconds. The green chemistry-derived polyurethane (gPU) showed high optical transparency, and we demonstrate the ability to tune the material stiffness of the printed structure along a gradient by controlling the exposure time and selecting various amine compounds. High-resolution 3D biomimetic structures with smooth curves and complex contours were printed using our gPU. High cell viability (over 95%) was demonstrated during cytocompatibility testing using C3H 10T1/2 cells seeded directly on the printed structures.

  7. Confocal Image 3D Surface Measurement with Optical Fiber Plate

    Institute of Scientific and Technical Information of China (English)

    WANG Zhao; ZHU Sheng-cheng; LI Bing; TAN Yu-shan

    2004-01-01

    A whole-field 3D surface measurement system for semiconductor wafer inspection is described.The system consists of an optical fiber plate,which can split the light beam into N2 subbeams to realize the whole-field inspection.A special prism is used to separate the illumination light and signal light.This setup is characterized by high precision,high speed and simple structure.

  8. Optical Sensors and Methods for Underwater 3D Reconstruction

    Directory of Open Access Journals (Sweden)

    Miquel Massot-Campos

    2015-12-01

    Full Text Available This paper presents a survey on optical sensors and methods for 3D reconstruction in underwater environments. The techniques to obtain range data have been listed and explained, together with the different sensor hardware that makes them possible. The literature has been reviewed, and a classification has been proposed for the existing solutions. New developments, commercial solutions and previous reviews in this topic have also been gathered and considered.

  9. Open-source 3D-printable optics equipment.

    Science.gov (United States)

    Zhang, Chenlong; Anzalone, Nicholas C; Faria, Rodrigo P; Pearce, Joshua M

    2013-01-01

    Just as the power of the open-source design paradigm has driven down the cost of software to the point that it is accessible to most people, the rise of open-source hardware is poised to drive down the cost of doing experimental science to expand access to everyone. To assist in this aim, this paper introduces a library of open-source 3-D-printable optics components. This library operates as a flexible, low-cost public-domain tool set for developing both research and teaching optics hardware. First, the use of parametric open-source designs using an open-source computer aided design package is described to customize the optics hardware for any application. Second, details are provided on the use of open-source 3-D printers (additive layer manufacturing) to fabricate the primary mechanical components, which are then combined to construct complex optics-related devices. Third, the use of the open-source electronics prototyping platform are illustrated as control for optical experimental apparatuses. This study demonstrates an open-source optical library, which significantly reduces the costs associated with much optical equipment, while also enabling relatively easily adapted customizable designs. The cost reductions in general are over 97%, with some components representing only 1% of the current commercial investment for optical products of similar function. The results of this study make its clear that this method of scientific hardware development enables a much broader audience to participate in optical experimentation both as research and teaching platforms than previous proprietary methods.

  10. Open-source 3D-printable optics equipment.

    Directory of Open Access Journals (Sweden)

    Chenlong Zhang

    Full Text Available Just as the power of the open-source design paradigm has driven down the cost of software to the point that it is accessible to most people, the rise of open-source hardware is poised to drive down the cost of doing experimental science to expand access to everyone. To assist in this aim, this paper introduces a library of open-source 3-D-printable optics components. This library operates as a flexible, low-cost public-domain tool set for developing both research and teaching optics hardware. First, the use of parametric open-source designs using an open-source computer aided design package is described to customize the optics hardware for any application. Second, details are provided on the use of open-source 3-D printers (additive layer manufacturing to fabricate the primary mechanical components, which are then combined to construct complex optics-related devices. Third, the use of the open-source electronics prototyping platform are illustrated as control for optical experimental apparatuses. This study demonstrates an open-source optical library, which significantly reduces the costs associated with much optical equipment, while also enabling relatively easily adapted customizable designs. The cost reductions in general are over 97%, with some components representing only 1% of the current commercial investment for optical products of similar function. The results of this study make its clear that this method of scientific hardware development enables a much broader audience to participate in optical experimentation both as research and teaching platforms than previous proprietary methods.

  11. Large optical 3D MEMS switches in access networks

    Science.gov (United States)

    Madamopoulos, Nicholas; Kaman, Volkan; Yuan, Shifu; Jerphagnon, Olivier; Helkey, Roger; Bowers, John E.

    2007-09-01

    Interest is high among residential customers and businesses for advanced, broadband services such as fast Internet access, electronic commerce, video-on-demand, digital broadcasting, teleconferencing and telemedicine. In order to satisfy such growing demand of end-customers, access technologies such as fiber-to-the-home/building (FTTH/B) are increasingly being deployed. Carriers can reduce maintenance costs, minimize technology obsolescence and introduce new services easily by reducing active elements in the fiber access network. However, having a passive optical network (PON) also introduces operational and maintenance challenges. Increased diagnostic monitoring capability of the network becomes a necessity as more and more fibers are provisioned to deliver services to the end-customers. This paper demonstrates the clear advantages that large 3D optical MEMS switches offer in solving these access network problems. The advantages in preventative maintenance, remote monitoring, test and diagnostic capability are highlighted. The low optical insertion loss for all switch optical connections of the switch enables the monitoring, grooming and serving of a large number of PON lines and customers. Furthermore, the 3D MEMS switch is transparent to optical wavelengths and data formats, thus making it easy to incorporate future upgrades, such higher bit rates or DWDM overlay to a PON.

  12. Total body irradiation with a compensator fabricated using a 3D optical scanner and a 3D printer

    Science.gov (United States)

    Park, So-Yeon; Kim, Jung-in; Joo, Yoon Ha; Lee, Jung Chan; Park, Jong Min

    2017-05-01

    We propose bilateral total body irradiation (TBI) utilizing a 3D printer and a 3D optical scanner. We acquired surface information of an anthropomorphic phantom with the 3D scanner and fabricated the 3D compensator with the 3D printer, which could continuously compensate for the lateral missing tissue of an entire body from the beam’s eye view. To test the system’s performance, we measured doses with optically stimulated luminescent dosimeters (OSLDs) as well as EBT3 films with the anthropomorphic phantom during TBI without a compensator, conventional bilateral TBI, and TBI with the 3D compensator (3D TBI). The 3D TBI showed the most uniform dose delivery to the phantom. From the OSLD measurements of the 3D TBI, the deviations between the measured doses and the prescription dose ranged from  -6.7% to 2.4% inside the phantom and from  -2.3% to 0.6% on the phantom’s surface. From the EBT3 film measurements, the prescription dose could be delivered to the entire body of the phantom within  ±10% accuracy, except for the chest region, where tissue heterogeneity is extreme. The 3D TBI doses were much more uniform than those of the other irradiation techniques, especially in the anterior-to-posterior direction. The 3D TBI was advantageous, owing to its uniform dose delivery as well as its efficient treatment procedure.

  13. Total body irradiation with a compensator fabricated using a 3D optical scanner and a 3D printer.

    Science.gov (United States)

    Park, So-Yeon; Kim, Jung-In; Joo, Yoon Ha; Lee, Jung Chan; Park, Jong Min

    2017-05-07

    We propose bilateral total body irradiation (TBI) utilizing a 3D printer and a 3D optical scanner. We acquired surface information of an anthropomorphic phantom with the 3D scanner and fabricated the 3D compensator with the 3D printer, which could continuously compensate for the lateral missing tissue of an entire body from the beam's eye view. To test the system's performance, we measured doses with optically stimulated luminescent dosimeters (OSLDs) as well as EBT3 films with the anthropomorphic phantom during TBI without a compensator, conventional bilateral TBI, and TBI with the 3D compensator (3D TBI). The 3D TBI showed the most uniform dose delivery to the phantom. From the OSLD measurements of the 3D TBI, the deviations between the measured doses and the prescription dose ranged from  -6.7% to 2.4% inside the phantom and from  -2.3% to 0.6% on the phantom's surface. From the EBT3 film measurements, the prescription dose could be delivered to the entire body of the phantom within  ±10% accuracy, except for the chest region, where tissue heterogeneity is extreme. The 3D TBI doses were much more uniform than those of the other irradiation techniques, especially in the anterior-to-posterior direction. The 3D TBI was advantageous, owing to its uniform dose delivery as well as its efficient treatment procedure.

  14. Optical parametric oscillators in isotropic photonic crystals and cavities: 3D time domain analysis

    OpenAIRE

    Conti, Claudio; Di Falco, Andrea; Assanto, Gaetano

    2004-01-01

    We investigate optical parametric oscillations through four-wave mixing in resonant cavities and photonic crystals. The theoretical analysis underlines the relevant features of the phenomenon and the role of the density of states. Using fully vectorial 3D time-domain simulations, including both dispersion and nonlinear polarization, for the first time we address this process in a face centered cubic lattice and in a photonic crystal slab. The results lead the way to the development of novel p...

  15. Nonlinear Optical Rectennas

    CERN Document Server

    Stolz, A; Markey, L; Francs, G Colas des; Bouhelier, A

    2013-01-01

    We introduce strongly-coupled optical gap antennas to interface optical radiation with current-carrying electrons at the nanoscale. The transducer relies on the nonlinear optical and electrical properties of an optical antenna operating in the tunneling regime. We discuss the underlying physical mechanisms controlling the conversion and demonstrate that a two-wire optical antenna can provide advanced optoelectronic functionalities beyond tailoring the electromagnetic response of a single emitter. Interfacing an electronic command layer with a nanoscale optical device may thus be facilitated by the optical rectennas discussed here.

  16. 3D Human cartilage surface characterization by optical coherence tomography

    Science.gov (United States)

    Brill, Nicolai; Riedel, Jörn; Schmitt, Robert; Tingart, Markus; Truhn, Daniel; Pufe, Thomas; Jahr, Holger; Nebelung, Sven

    2015-10-01

    Early diagnosis and treatment of cartilage degeneration is of high clinical interest. Loss of surface integrity is considered one of the earliest and most reliable signs of degeneration, but cannot currently be evaluated objectively. Optical Coherence Tomography (OCT) is an arthroscopically available light-based non-destructive real-time imaging technology that allows imaging at micrometre resolutions to millimetre depths. As OCT-based surface evaluation standards remain to be defined, the present study investigated the diagnostic potential of 3D surface profile parameters in the comprehensive evaluation of cartilage degeneration. To this end, 45 cartilage samples of different degenerative grades were obtained from total knee replacements (2 males, 10 females; mean age 63.8 years), cut to standard size and imaged using a spectral-domain OCT device (Thorlabs, Germany). 3D OCT datasets of 8  ×  8, 4  ×  4 and 1  ×  1 mm (width  ×  length) were obtained and pre-processed (image adjustments, morphological filtering). Subsequent automated surface identification algorithms were used to obtain the 3D primary profiles, which were then filtered and processed using established algorithms employing ISO standards. The 3D surface profile thus obtained was used to calculate a set of 21 3D surface profile parameters, i.e. height (e.g. Sa), functional (e.g. Sk), hybrid (e.g. Sdq) and segmentation-related parameters (e.g. Spd). Samples underwent reference histological assessment according to the Degenerative Joint Disease classification. Statistical analyses included calculation of Spearman’s rho and assessment of inter-group differences using the Kruskal Wallis test. Overall, the majority of 3D surface profile parameters revealed significant degeneration-dependent differences and correlations with the exception of severe end-stage degeneration and were of distinct diagnostic value in the assessment of surface integrity. None of the 3D

  17. Simulation of Fully Nonlinear 3-D Numerical Wave Tank

    Institute of Scientific and Technical Information of China (English)

    张晓兔; 滕斌; 宁德志

    2004-01-01

    A fully nonlinear numerical wave tank (NWT) has been simulated by use of a three-dimensional higher order boundary element method (HOBEM) in the time domain. Within the frame of potential flow and the adoption of simply Rankine source, the resulting boundary integral equation is repeatedly solved at each time step and the fully nonlinear free surface boundary conditions are integrated with time to update its position and boundary values. A smooth technique is also adopted in order to eliminate the possible saw-tooth numerical instabilities. The incident wave at the uptank is given as theoretical wave in this paper. The outgoing waves are absorbed inside a damping zone by spatially varying artificial damping on the free surface at the wave tank end. The numerical results show that the NWT developed by these approaches has a high accuracy and good numerical stability.

  18. Imaging of discontinuities in nonlinear 3-D seismic inversion

    Energy Technology Data Exchange (ETDEWEB)

    Carrion, P.M.; Cerveny, V. (PPPG/UFBA, Salvador (Brazil))

    1990-09-01

    The authors present a nonlinear approach for reconstruction of discontinuities in geological environment (earth's crust, say). The advantage of the proposed method is that it is not limited to a Born approximation (small angles of propagation and weak scatterers). One can expect significantly better images since larger apertures including wide angle reflection arrivals can be incorporated into the imaging operator. In this paper, they treat only compressional body waves: shear and surface waves are considered as noise.

  19. Optical characterization of different types of 3D displays

    Science.gov (United States)

    Boher, Pierre; Leroux, Thierry; Bignon, Thibault; Collomb-Patton, Véronique

    2012-03-01

    All 3D displays have the same intrinsic method to induce depth perception. They provide different images in the left and right eye of the observer to obtain the stereoscopic effect. The three most common solutions already available on the market are active glass, passive glass and auto-stereoscopic 3D displays. The three types of displays are based on different physical principle (polarization, time selection or spatial emission) and consequently require different measurement instruments and techniques. In the proposed paper, we present some of these solutions and the technical characteristics that can be obtained to compare the displays. We show in particular that local and global measurements can be made in the three cases to access to different characteristics. We also discuss the new technologies currently under development and their needs in terms of optical characterization.

  20. Innovations in 3D printing: a 3D overview from optics to organs.

    Science.gov (United States)

    Schubert, Carl; van Langeveld, Mark C; Donoso, Larry A

    2014-02-01

    3D printing is a method of manufacturing in which materials, such as plastic or metal, are deposited onto one another in layers to produce a three dimensional object, such as a pair of eye glasses or other 3D objects. This process contrasts with traditional ink-based printers which produce a two dimensional object (ink on paper). To date, 3D printing has primarily been used in engineering to create engineering prototypes. However, recent advances in printing materials have now enabled 3D printers to make objects that are comparable with traditionally manufactured items. In contrast with conventional printers, 3D printing has the potential to enable mass customisation of goods on a large scale and has relevance in medicine including ophthalmology. 3D printing has already been proved viable in several medical applications including the manufacture of eyeglasses, custom prosthetic devices and dental implants. In this review, we discuss the potential for 3D printing to revolutionise manufacturing in the same way as the printing press revolutionised conventional printing. The applications and limitations of 3D printing are discussed; the production process is demonstrated by producing a set of eyeglass frames from 3D blueprints.

  1. Ultrafast nonlinear optics

    CERN Document Server

    Leburn, Christopher; Reid, Derryck

    2013-01-01

    The field of ultrafast nonlinear optics is broad and multidisciplinary, and encompasses areas concerned with both the generation and measurement of ultrashort pulses of light, as well as those concerned with the applications of such pulses. Ultrashort pulses are extreme events – both in terms of their durations, and also the high peak powers which their short durations can facilitate. These extreme properties make them powerful experiment tools. On one hand, their ultrashort durations facilitate the probing and manipulation of matter on incredibly short timescales. On the other, their ultrashort durations can facilitate high peak powers which can drive highly nonlinear light-matter interaction processes. Ultrafast Nonlinear Optics covers a complete range of topics, both applied and fundamental in nature, within the area of ultrafast nonlinear optics. Chapters 1 to 4 are concerned with the generation and measurement of ultrashort pulses. Chapters 5 to 7 are concerned with fundamental applications of ultrasho...

  2. 3D OPTICAL AND IR SPECTROSCOPY OF EXCEPTIONAL HII GALAXIES

    Directory of Open Access Journals (Sweden)

    E. Telles

    2009-01-01

    Full Text Available In this contribution I will very brie y summarize some recent results obtained applying 3D spectroscopy to observations of the well known HII galaxy II Zw 40, both in the optical and near-IR. I have studied the distribution of the dust in the starburst region, the velocity and velocity dispersion, and the geometry of the molecular hydrogen and ionized gas. I found a clear correlation between the component of the ISM and the velocity eld suggesting that the latter has a fundamental role in de ning the modes of the star formation process.

  3. Optical monitoring of scoliosis by 3D medical laser scanner

    Science.gov (United States)

    Rodríguez-Quiñonez, Julio C.; Sergiyenko, Oleg Yu.; Preciado, Luis C. Basaca; Tyrsa, Vera V.; Gurko, Alexander G.; Podrygalo, Mikhail A.; Lopez, Moises Rivas; Balbuena, Daniel Hernandez

    2014-03-01

    Three dimensional recording of the human body surface or anatomical areas have gained importance in many medical applications. In this paper, our 3D Medical Laser Scanner is presented. It is based on the novel principle of dynamic triangulation. We analyze the method of operation, medical applications, orthopedically diseases as Scoliosis and the most common types of skin to employ the system the most proper way. It is analyzed a group of medical problems related to the application of optical scanning in optimal way. Finally, experiments are conducted to verify the performance of the proposed system and its method uncertainty.

  4. Nonlinear effects in optical fibers

    CERN Document Server

    Ferreira, Mario F

    2011-01-01

    Cutting-edge coverage of nonlinear phenomena occurring inside optical fibers Nonlinear fiber optics is a specialized part of fiber optics dealing with optical nonlinearities and their applications. As fiber-optic communication systems have become more advanced and complex, the nonlinear effects in optical fibers have increased in importance, as they adversely affect system performance. Paradoxically, the same nonlinear phenomena also offer the promise of addressing the bandwidth bottleneck for signal processing for future ultra-high speed optical networks. Nonlinear Effects in Optical Fiber

  5. 3D refractive index measurements of special optical fibers

    Science.gov (United States)

    Yan, Cheng; Huang, Su-Juan; Miao, Zhuang; Chang, Zheng; Zeng, Jun-Zhang; Wang, Ting-Yun

    2016-09-01

    A digital holographic microscopic chromatography-based approach with considerably improved accuracy, simplified configuration and performance stability is proposed to measure three dimensional refractive index of special optical fibers. Based on the approach, a measurement system is established incorporating a modified Mach-Zehnder interferometer and lab-developed supporting software for data processing. In the system, a phase projection distribution of an optical fiber is utilized to obtain an optimal digital hologram recorded by a CCD, and then an angular spectrum theory-based algorithm is adopted to extract the phase distribution information of an object wave. The rotation of the optic fiber enables the experimental measurements of multi-angle phase information. Based on the filtered back projection algorithm, a 3D refraction index of the optical fiber is thus obtained at high accuracy. To evaluate the proposed approach, both PANDA fibers and special elliptical optical fiber are considered in the system. The results measured in PANDA fibers agree well with those measured using S14 Refractive Index Profiler, which is, however, not suitable for measuring the property of a special elliptical fiber.

  6. Linearizing nonlinear optics

    CERN Document Server

    Schmidt, Bruno E; Ernotte, Guilmot; Clerici, Matteo; Morandotti, Roberto; Ibrahim, Heide; Legare, Francois

    2016-01-01

    In the framework of linear optics, light fields do not interact with each other in a medium. Yet, when their field amplitude becomes comparable to the electron binding energies of matter, the nonlinear motion of these electrons emits new dipole radiation whose amplitude, frequency and phase differ from the incoming fields. Such high fields are typically achieved with ultra-short, femtosecond (1fs = 10-15 sec.) laser pulses containing very broad frequency spectra. Here, the matter not only couples incoming and outgoing fields but also causes different spectral components to interact and mix through a convolution process. In this contribution, we describe how frequency domain nonlinear optics overcomes the shortcomings arising from this convolution in conventional time domain nonlinear optics1. We generate light fields with previously inaccessible properties because the uncontrolled coupling of amplitudes and phases is turned off. For example, arbitrary phase functions are transferred linearly to the second har...

  7. High-order finite difference solution for 3D nonlinear wave-structure interaction

    DEFF Research Database (Denmark)

    Ducrozet, Guillaume; Bingham, Harry B.; Engsig-Karup, Allan Peter;

    2010-01-01

    This contribution presents our recent progress on developing an efficient fully-nonlinear potential flow model for simulating 3D wave-wave and wave-structure interaction over arbitrary depths (i.e. in coastal and offshore environment). The model is based on a high-order finite difference scheme...... OceanWave3D presented in [1, 2]. A nonlinear decomposition of the solution into incident and scattered fields is used to increase the efficiency of the wave-structure interaction problem resolution. Application of the method to the diffraction of nonlinear waves around a fixed, bottom mounted circular...

  8. Fundamentals of nonlinear optics

    CERN Document Server

    Powers, Peter E

    2011-01-01

    Peter Powers's rigorous but simple description of a difficult field keeps the reader's attention throughout. … All chapters contain a list of references and large numbers of practice examples to be worked through. … By carefully working through the proposed problems, students will develop a sound understanding of the fundamental principles and applications. … the book serves perfectly for an introductory-level course for second- and third-order nonlinear optical phenomena. The author's writing style is refreshing and original. I expect that Fundamentals of Nonlinear Optics will fast become pop

  9. Volumetric (3D) compressive sensing spectral domain optical coherence tomography.

    Science.gov (United States)

    Xu, Daguang; Huang, Yong; Kang, Jin U

    2014-11-01

    In this work, we proposed a novel three-dimensional compressive sensing (CS) approach for spectral domain optical coherence tomography (SD OCT) volumetric image acquisition and reconstruction. Instead of taking a spectral volume whose size is the same as that of the volumetric image, our method uses a sub set of the original spectral volume that is under-sampled in all three dimensions, which reduces the amount of spectral measurements to less than 20% of that required by the Shan-non/Nyquist theory. The 3D image is recovered from the under-sampled spectral data dimension-by-dimension using the proposed three-step CS reconstruction strategy. Experimental results show that our method can significantly reduce the sampling rate required for a volumetric SD OCT image while preserving the image quality.

  10. Nonlinear fibre optics overview

    DEFF Research Database (Denmark)

    Travers, J. C.; Frosz, Michael Henoch; Dudley, J. M.

    2010-01-01

    , provides a background to the associated nonlinear optical processes, treats the generation mechanisms from continuous wave to femtosecond pulse pump regimes and highlights the diverse applications. A full discussion of numerical methods and comprehensive computer code are also provided, enabling readers...

  11. Handbook of nonlinear optical crystals

    CERN Document Server

    Dmitriev, Valentin G; Nikogosyan, David N

    1991-01-01

    This Handbook of Nonlinear Optical Crystals provides a complete description of the properties and applications of nonlinear crystals In addition, it presents the most important equations for calculating the main parameters of nonlinear frequency converters This comprehensive reference work will be of great value to all scientists and engineers working in nonlinear optics, quantum electronics and laser physics

  12. Nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2012-01-01

    Since the 4e appeared, a fast evolution of the field has occurred. The 5e of this classic work provides an up-to-date account of the nonlinear phenomena occurring inside optical fibers, the basis of all our telecommunications infastructure as well as being used in the medical field. Reflecting the big developments in research, this new edition includes major new content: slow light effects, which offers a reduction in noise and power consumption and more ordered network traffic-stimulated Brillouin scattering; vectorial treatment of highly nonlinear fibers; and a brand new chapter o

  13. Effects of nonlinear strength parameters on stability of 3D soil slopes

    Institute of Scientific and Technical Information of China (English)

    高玉峰; 吴迪; 张飞; 秦红玉; 朱德胜

    2016-01-01

    Actual slope stability problems have three-dimensional (3D) characteristics and the soils of slopes have curved failure envelopes. This incorporates a power-law nonlinear failure criterion into the kinematic approach of limit analysis to conduct the evaluation of the stability of 3D slopes. A tangential technique is adopted to simplify the nonlinear failure criterion in the form of equivalent Mohr-Coulomb strength parameters. A class of 3D admissible rotational failure mechanisms is selected for soil slopes including three types of failure mechanisms: face failure, base failure, and toe failure. The upper-bound solutions and corresponding critical slip surfaces can be obtained by an efficient optimization method. The results indicate that the nonlinear parameters have significant influences on the assessment of slope stability, especially on the type of failure mechanism. The effects of nonlinear parameters appear to be pronounced for gentle slopes constrained to a narrow width. Compared with the solutions derived from plane-strain analysis, the 3D solutions are more sensitive to the values of nonlinear parameters.

  14. Optical 3D sensor for large objects in industrial application

    Science.gov (United States)

    Kuhmstedt, Peter; Heinze, Matthias; Himmelreich, Michael; Brauer-Burchardt, Christian; Brakhage, Peter; Notni, Gunther

    2005-06-01

    A new self calibrating optical 3D measurement system using fringe projection technique named "kolibri 1500" is presented. It can be utilised to acquire the all around shape of large objects. The basic measuring principle is the phasogrammetric approach introduced by the authors /1, 2/. The "kolibri 1500" consists of a stationary system with a translation unit for handling of objects. Automatic whole body measurement is achieved by using sensor head rotation and changeable object position, which can be done completely computer controlled. Multi-view measurement is realised by using the concept of virtual reference points. In this way no matching procedures or markers are necessary for the registration of the different images. This makes the system very flexible to realise different measurement tasks. Furthermore, due to self calibrating principle mechanical alterations are compensated. Typical parameters of the system are: the measurement volume extends from 400 mm up to 1500 mm max. length, the measurement time is between 2 min for 12 images up to 20 min for 36 images and the measurement accuracy is below 50μm.The flexibility makes the measurement system useful for a wide range of applications such as quality control, rapid prototyping, design and CAD/CAM which will be shown in the paper.

  15. Cordless hand-held optical 3D sensor

    Science.gov (United States)

    Munkelt, Christoph; Bräuer-Burchardt, Christian; Kühmstedt, Peter; Schmidt, Ingo; Notni, Gunther

    2007-07-01

    A new mobile optical 3D measurement system using phase correlation based fringe projection technique will be presented. The sensor consist of a digital projection unit and two cameras in a stereo arrangement, whereby both are battery powered. The data transfer to a base station will be done via WLAN. This gives the possibility to use the system in complicate, remote measurement situations, which are typical in archaeology and architecture. In the measurement procedure the sensor will be hand-held by the user, illuminating the object with a sequence of less than 10 fringe patterns, within a time below 200 ms. This short sequence duration was achieved by a new approach, which combines the epipolar constraint with robust phase correlation utilizing a pre-calibrated sensor head, containing two cameras and a digital fringe projector. Furthermore, the system can be utilized to acquire the all around shape of objects by using the phasogrammetric approach with virtual land marks introduced by the authors 1, 2. This way no matching procedures or markers are necessary for the registration of multiple views, which makes the system very flexible in accomplishing different measurement tasks. The realized measurement field is approx. 100 mm up to 400 mm in diameter. The mobile character makes the measurement system useful for a wide range of applications in arts, architecture, archaeology and criminology, which will be shown in the paper.

  16. Study on portable optical 3D coordinate measuring system

    Science.gov (United States)

    Ren, Tongqun; Zhu, Jigui; Guo, Yinbiao

    2009-05-01

    A portable optical 3D coordinate measuring system based on digital Close Range Photogrammetry (CRP) technology and binocular stereo vision theory is researched. Three ultra-red LED with high stability is set on a hand-hold target to provide measuring feature and establish target coordinate system. Ray intersection based field directional calibrating is done for the intersectant binocular measurement system composed of two cameras by a reference ruler. The hand-hold target controlled by Bluetooth wireless communication is free moved to implement contact measurement. The position of ceramic contact ball is pre-calibrated accurately. The coordinates of target feature points are obtained by binocular stereo vision model from the stereo images pair taken by cameras. Combining radius compensation for contact ball and residual error correction, object point can be resolved by transfer of axes using target coordinate system as intermediary. This system is suitable for on-field large-scale measurement because of its excellent portability, high precision, wide measuring volume, great adaptability and satisfying automatization. It is tested that the measuring precision is near to +/-0.1mm/m.

  17. Essentials of nonlinear optics

    CERN Document Server

    Murti, Y V G S

    2014-01-01

    Current literature on Nonlinear Optics varies widely in terms of content, style, and coverage of specific topics, relative emphasis of areas and the depth of treatment. While most of these books are excellent resources for the researchers, there is a strong need for books appropriate for presenting the subject at the undergraduate or postgraduate levels in Universities. The need for such a book to serve as a textbook at the level of the bachelors and masters courses was felt by the authors while teaching courses on nonlinear optics to students of both science and engineering during the past two decades. This book has emerged from an attempt to address the requirement of presenting the subject at college level. A one-semester course covering the essentials can effectively be designed based on this.

  18. Nonlinear tracking control of a 3-D overhead crane with friction and payload compensations

    OpenAIRE

    Anh-Huy Vo; Quoc-Toan Truong; Ha-Quang-Thinh Ngo; Quoc-Chi Nguyen

    2016-01-01

    In this paper, a nonlinear adaptive control of a 3D overhead crane is investigated. A dynamic model of the overhead crane was developed, where the crane system is assumed as a lumped mass model. Under the mutual effects of the sway motions of the payload and the hoisting motion, the nonlinear behavior of the crane system is considered. A nonlinear control model-based scheme was designed to achieve the three objectives: (i) drive the crane system to the desired positions, (ii) suppresses the v...

  19. Improved 3D Superresolution Localization Microscopy Using Adaptive Optics

    CERN Document Server

    Piro, Nicolas; Olivier, Nicolas; Manley, Suliana

    2014-01-01

    We demonstrate a new versatile method for 3D super-resolution microscopy by using a deformable mirror to shape the point spread function of our microscope in a continuous and controllable way. We apply this for 3D STORM imaging of microtubules.

  20. Configurable Input Devices for 3D Interaction using Optical Tracking

    NARCIS (Netherlands)

    Rhijn, A.J. van

    2007-01-01

    Three-dimensional interaction with virtual objects is one of the aspects that needs to be addressed in order to increase the usability and usefulness of virtual reality. Human beings have difficulties understanding 3D spatial relationships and manipulating 3D user interfaces, which require the contr

  1. Remote Atmospheric Nonlinear Optical Magnetometry

    Science.gov (United States)

    2014-04-28

    Boyd , Nonlinear Optics (Elsevier, Burlington, MA, 2008). [13] M. Scully and S. Zubairy, Quantum Optics (Cambridge U. Press, Cambridge, UK, 1997...Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6703--14-9548 Remote Atmospheric Nonlinear Optical Magnetometry PhilliP SPrangle...b. ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT Remote Atmospheric Nonlinear Optical Magnetometry Phillip Sprangle, Luke

  2. Terahertz Nonlinear Optics in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias C.

    2013-01-01

    We demonstrate the nonlinear optical effects – selfphase modulation and saturable absorption of a single-cycle THz pulse in a semiconductor. Resulting from THz-induced modulation of Drude plasma, these nonlinear optical effects, in particular, lead to self-shortening and nonlinear spectral...

  3. Magneto-acoustic waves in sunspots: first results from a new 3D nonlinear magnetohydrodynamic code

    CERN Document Server

    Felipe, T; Collados, M

    2010-01-01

    Waves observed in the photosphere and chromosphere of sunspots show complex dynamics and spatial patterns. The interpretation of high-resolution sunspot wave observations requires modeling of three-dimensional non-linear wave propagation and mode transformation in the sunspot upper layers in realistic spot model atmospheres. Here we present the first results of such modeling. We have developed a 3D non-linear numerical code specially designed to calculate the response of magnetic structures in equilibrium to an arbitrary perturbation. The code solves the 3D nonlinear MHD equations for perturbations; it is stabilized by hyper-diffusivity terms and is fully parallelized. The robustness of the code is demonstrated by a number of standard tests. We analyze several simulations of a sunspot perturbed by pulses of different periods at subphotospheric level, from short periods, introduced for academic purposes, to longer and realistic periods of three and five minutes. We present a detailed description of the three-d...

  4. Optical 3D shape measurement for dynamic process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    3D shape dynamic measurement is essential to the study of machine vision, hydromechanics, high-speed rotation, deformation of material, stress analysis, deformation in impact, explosion process and biomedicine. in recent years. In this paper,the results of our research, including the theoretical analysis, some feasible methods and relevant verifying experiment results, are compendiously reported. At present, these results have been used in our assembling instruments for 3D shape measurement of dynamic process.

  5. Nonlinear optical thin films

    Science.gov (United States)

    Leslie, Thomas M.

    1993-01-01

    A focused approach to development and evaluation of organic polymer films for use in optoelectronics is presented. The issues and challenges that are addressed include: (1) material synthesis, purification, and the tailoring of the material properties; (2) deposition of uniform thin films by a variety of methods; (3) characterization of material physical properties (thermal, electrical, optical, and electro-optical); and (4) device fabrication and testing. Photonic materials, devices, and systems were identified as critical technology areas by the Department of Commerce and the Department of Defense. This approach offers strong integration of basic material issues through engineering applications by the development of materials that can be exploited as the active unit in a variety of polymeric thin film devices. Improved materials were developed with unprecedented purity and stability. The absorptive properties can be tailored and controlled to provide significant improvement in propagation losses and nonlinear performance. Furthermore, the materials were incorporated into polymers that are highly compatible with fabrication and patterning processes for integrated optical devices and circuits. By simultaneously addressing the issues of materials development and characterization, keeping device design and fabrication in mind, many obstacles were overcome for implementation of these polymeric materials and devices into systems. We intend to considerably improve the upper use temperature, poling stability, and compatibility with silicon based devices. The principal device application that was targeted is a linear electro-optic modulation etalon. Organic polymers need to be properly designed and coupled with existing integrated circuit technology to create new photonic devices for optical communication, image processing, other laser applications such as harmonic generation, and eventually optical computing. The progression from microscopic sample to a suitable film

  6. Nonlinear Optical Terahertz Technology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Our approach is based on high-Q optical WGM resonators made with a nonlinear crystal. Such resonators have been demonstrated to dramatically enhance nonlinear...

  7. Joint Applied Optics and Chinese Optics Letters Feature Introduction: Digital Holography and 3D Imaging

    Institute of Scientific and Technical Information of China (English)

    Ting-Chung Poon; Changhe Zhou; Toyohiko Yatagai; Byoungho Lee; Hongchen Zhai

    2011-01-01

    This feature issue is the fifth installment on digital holography since its inception four years ago.The last four issues have been published after the conclusion of each Topical Meeting "Digital Holography and 3D imaging (DH)." However,this feature issue includes a new key feature-Joint Applied Optics and Chinese Optics Letters Feature Issue.The DH Topical Meeting is the world's premier forum for disseminating the science and technology geared towards digital holography and 3D information processing.Since the meeting's inception in 2007,it has steadily and healthily grown to 130 presentations this year,held in Tokyo,Japan,May 2011.

  8. Air-structured optical fibre drawn from a 3D-printed preform

    CERN Document Server

    Cook, Kevin; Leon-Saval, Sergio; Reid, Zane; Hossain, Md Arafat; Comatti, Jade-Edouard; Luo, Yanhua; Peng, Gang-Ding

    2016-01-01

    A structured optical fibre is drawn from a 3D-printed structured preform. Preforms containing a single ring of holes around the core are fabricated using filament made from a modified butadiene polymer. More broadly, 3D printers capable of processing soft glasses, silica and other materials are likely to come on line in the not-so distant future. 3D printing of optical preforms signals a new milestone in optical fibre manufacture.

  9. Flexible Holographic Fabrication of 3D Photonic Crystal Templates with Polarization Control through a 3D Printed Reflective Optical Element

    Directory of Open Access Journals (Sweden)

    David Lowell

    2016-07-01

    Full Text Available In this paper, we have systematically studied the holographic fabrication of three-dimensional (3D structures using a single 3D printed reflective optical element (ROE, taking advantage of the ease of design and 3D printing of the ROE. The reflective surface was setup at non-Brewster angles to reflect both s- and p-polarized beams for the interference. The wide selection of reflective surface materials and interference angles allow control of the ratio of s- and p-polarizations, and intensity ratio of side-beam to central beam for interference lithography. Photonic bandgap simulations have also indicated that both s and p-polarized waves are sometimes needed in the reflected side beams for maximum photonic bandgap size and certain filling fractions of dielectric inside the photonic crystals. The flexibility of single ROE and single exposure based holographic fabrication of 3D structures was demonstrated with reflective surfaces of ROEs at non-Brewster angles, highlighting the capability of the ROE technique of producing umbrella configurations of side beams with arbitrary angles and polarizations and paving the way for the rapid throughput of various photonic crystal templates.

  10. Nonlinear tracking control of a 3-D overhead crane with friction and payload compensations

    Directory of Open Access Journals (Sweden)

    Anh-Huy Vo

    2016-07-01

    Full Text Available In this paper, a nonlinear adaptive control of a 3D overhead crane is investigated. A dynamic model of the overhead crane was developed, where the crane system is assumed as a lumped mass model. Under the mutual effects of the sway motions of the payload and the hoisting motion, the nonlinear behavior of the crane system is considered. A nonlinear control model-based scheme was designed to achieve the three objectives: (i drive the crane system to the desired positions, (ii suppresses the vibrations of the payload, and (iii velocity tracking of hoisting motion. The nonlinear control scheme employs adaptation laws that estimate unknown system parameters, friction forces and the mass of the payload. The estimated values were used to compute control forces applied to the trolley of the crane. The asymptotic stability of the crane system is investigated by using the Lyapunov method. The effectiveness of the proposed control scheme is verified by numerical simulation results.

  11. Validation of optical codes based on 3D nanostructures

    Science.gov (United States)

    Carnicer, Artur; Javidi, Bahram

    2017-05-01

    Image information encoding using random phase masks produce speckle-like noise distributions when the sample is propagated in the Fresnel domain. As a result, information cannot be accessed by simple visual inspection. Phase masks can be easily implemented in practice by attaching cello-tape to the plain-text message. Conventional 2D-phase masks can be generalized to 3D by combining glass and diffusers resulting in a more complex, physical unclonable function. In this communication, we model the behavior of a 3D phase mask using a simple approach: light is propagated trough glass using the angular spectrum of plane waves whereas the diffusor is described as a random phase mask and a blurring effect on the amplitude of the propagated wave. Using different designs for the 3D phase mask and multiple samples, we demonstrate that classification is possible using the k-nearest neighbors and random forests machine learning algorithms.

  12. Focus issue introduction: nonlinear optics.

    Science.gov (United States)

    Boulanger, Benoît; Cundiff, Steven T; Gauthier, Daniel J; Karlsson, Magnus; Lu, Yan-Qing; Norwood, Robert A; Skryabin, Dmitry; Taira, Takunori

    2011-11-07

    It is now fifty years since the original observation of second harmonic generation ushered in the field of nonlinear optics, close on the heels of the invention of the laser. This feature issue celebrates this anniversary with papers that span the range from new nonlinear optical materials, through the increasingly novel methods that have been developed for phase matching, to emerging areas such as nonlinear metamaterials and plasmonic enhancement of optical properties. It is clear that the next fifty years of nonlinear optics will witness a proliferation of new applications with increasing technological impact.

  13. Design of 3D isotropic metamaterial device using smart transformation optics.

    Science.gov (United States)

    Shin, Dongheok; Kim, Junhyun; Yoo, Do-Sik; Kim, Kyoungsik

    2015-08-24

    We report here a design method for a 3 dimensional (3D) isotropic transformation optical device using smart transformation optics. Inspired by solid mechanics, smart transformation optics regards a transformation optical medium as an elastic solid and deformations as coordinate transformations. Further developing from our previous work on 2D smart transformation optics, we introduce a method of 3D smart transformation optics to design 3D transformation optical devices by maintaining isotropic materials properties for all types of polarizations imposing free or nearly free boundary conditions. Due to the material isotropy, it is possible to fabricate such devices with structural metamaterials made purely of common dielectric materials. In conclusion, the practical importance of the method reported here lies in the fact that it enables us to fabricate, without difficulty, arbitrarily shaped 3D devices with existing 3D printing technology.

  14. An efficient flexible-order model for 3D nonlinear water waves

    DEFF Research Database (Denmark)

    Engsig-Karup, Allan Peter; Bingham, Harry B.; Lindberg, Ole

    2009-01-01

    The flexible-order, finite difference based fully nonlinear potential flow model described in [H.B. Bingham, H. Zhang, On the accuracy of finite difference solutions for nonlinear water waves, J. Eng. Math. 58 (2007) 211-228] is extended to three dimensions (3D). In order to obtain an optimal...... scaling of the solution effort multigrid is employed to precondition a GMRES iterative solution of the discretized Laplace problem. A robust multigrid method based on Gauss-Seidel smoothing is found to require special treatment of the boundary conditions along solid boundaries, and in particular...

  15. A 3-D nonlinear recursive digital filter for video image processing

    Science.gov (United States)

    Bauer, P. H.; Qian, W.

    1991-01-01

    This paper introduces a recursive 3-D nonlinear digital filter, which is capable of performing noise suppression without degrading important image information such as edges in space or time. It also has the property of unnoticeable bandwidth reduction immediately after a scene change, which makes the filter an attractive preprocessor to many interframe compression algorithms. The filter consists of a nonlinear 2-D spatial subfilter and a 1-D temporal filter. In order to achieve the required computational speed and increase the flexibility of the filter, all of the linear shift-variant filter modules are of the IIR type.

  16. Nonlinear dynamics of Airy-Vortex 3D wave packets: Emission of vortex light waves

    CERN Document Server

    Driben, Rodislav

    2014-01-01

    The dynamics of 3D Airy-vortex wave packets is studied under the action of strong self-focusing Kerr nonlinearity. Emissions of nonlinear 3D waves out of the main wave packets with the topological charges were demonstrated. Due to the conservation of the total angular momentum, charges of the emitted waves are equal to those carried by the parental light structure. The rapid collapse imposes a severe limitation on the propagation of multidimensional waves in Kerr media. However, the structure of the Airy beam carrier allows the coupling of light from the leading, most intense peak into neighboring peaks and consequently strongly postpones the collapse. The dependence of the critical input amplitude for the appearance of a fast collapse on the beam width is studied for wave packets with zero and non-zero topological charges. Wave packets carrying angular momentum are found to be much more resistant to the rapid collapse, especially those having small width.

  17. Nonlinear dynamics of Airy-vortex 3D wave packets: emission of vortex light waves.

    Science.gov (United States)

    Driben, Rodislav; Meier, Torsten

    2014-10-01

    The dynamics of 3D Airy-vortex wave packets is studied under the action of strong self-focusing Kerr nonlinearity. Emissions of nonlinear 3D waves out of the main wave packets with the topological charges were demonstrated. Because of the conservation of the total angular momentum, charges of the emitted waves are equal to those carried by the parental light structure. The rapid collapse imposes a severe limitation on the propagation of multidimensional waves in Kerr media. However, the structure of the Airy beam carrier allows the coupling of light from the leading, most intense peak into neighboring peaks and consequently strongly postpones the collapse. The dependence of the critical input amplitude for the appearance of a fast collapse on the beam width is studied for wave packets with zero and nonzero topological charges. Wave packets carrying angular momentum are found to be much more resistant to the rapid collapse.

  18. Model-based optical metrology and visualization of 3-D complex objects

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-li; LI A-meng; ZHAO Xiao-bo; GAO Peng-dong; TIAN Jin-dong; PENG Xiang

    2007-01-01

    This letter addresses several key issues in the process of model-based optical metrology, including three dimensional (3D) sensing, calibration, registration and fusion of range images, geometric representation, and visualization of reconstructed 3D model by taking into account the shape measurement of 3D complex structures,and some experimental results are presented.

  19. 3-D zebrafish embryo image filtering by nonlinear partial differential equations.

    Science.gov (United States)

    Rizzi, Barbara; Campana, Matteo; Zanella, Cecilia; Melani, Camilo; Cunderlik, Robert; Krivá, Zuzana; Bourgine, Paul; Mikula, Karol; Peyriéras, Nadine; Sarti, Alessandro

    2007-01-01

    We discuss application of nonlinear PDE based methods to filtering of 3-D confocal images of embryogenesis. We focus on the mean curvature driven and the regularized Perona-Malik equations, where standard as well as newly suggested edge detectors are used. After presenting the related mathematical models, the practical results are given and discussed by visual inspection and quantitatively using the mean Hausdorff distance.

  20. 3D computation of non-linear eddy currents: Variational method and superconducting cubic bulk

    Science.gov (United States)

    Pardo, Enric; Kapolka, Milan

    2017-09-01

    Computing the electric eddy currents in non-linear materials, such as superconductors, is not straightforward. The design of superconducting magnets and power applications needs electromagnetic computer modeling, being in many cases a three-dimensional (3D) problem. Since 3D problems require high computing times, novel time-efficient modeling tools are highly desirable. This article presents a novel computing modeling method based on a variational principle. The self-programmed implementation uses an original minimization method, which divides the sample into sectors. This speeds-up the computations with no loss of accuracy, while enabling efficient parallelization. This method could also be applied to model transients in linear materials or networks of non-linear electrical elements. As example, we analyze the magnetization currents of a cubic superconductor. This 3D situation remains unknown, in spite of the fact that it is often met in material characterization and bulk applications. We found that below the penetration field and in part of the sample, current flux lines are not rectangular and significantly bend in the direction parallel to the applied field. In conclusion, the presented numerical method is able to time-efficiently solve fully 3D situations without loss of accuracy.

  1. (HEL MRI) 3D Meta Optics for High Energy Lasers

    Science.gov (United States)

    2016-09-13

    optical communication link using orbital angular momentum multiplexing ." Optics express 24, no. 9 (2016): 9794-9805. 3. Li, Yuan, Wenzhe Li, J. Miller, and...Magnusson, R.; Binun, P.; McCormick, K., "Wavelength Selection and Polarization Multiplexing of Blue Laser Diodes," in Photonics Technology Letters, IEEE...spatial multiplexing can take advantage of a non-Gaussian beam profile. If the components are to be used as out-couplers in bulk lasers , the optics

  2. Comparative Results on 3D Navigation of Quadrotor using two Nonlinear Model based Controllers

    Science.gov (United States)

    Bouzid, Y.; Siguerdidjane, H.; Bestaoui, Y.

    2017-01-01

    Recently the quadrotors are being increasingly employed in both military and civilian areas where a broad range of nonlinear flight control techniques are successfully implemented. With this advancement, it has become necessary to investigate the efficiency of these flight controllers by studying theirs features and compare their performance. In this paper, the control of Unmanned Aerial Vehicle (UAV) quadrotor, using two different approaches, is presented. The first controller is Nonlinear PID (NLPID) whilst the second one is Nonlinear Internal Model Control (NLIMC) that are used for the stabilization as well as for the 3D trajectory tracking. The numerical simulations have shown satisfactory results using nominal system model or disturbed model for both of them. The obtained results are analyzed with respect to several criteria for the sake of comparison.

  3. Applications of nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2008-01-01

    * The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The bo

  4. Focus issue introduction: nonlinear optics 2013.

    Science.gov (United States)

    Dadap, Jerry I; Karlsson, Magnus; Panoiu, Nicolae C

    2013-12-16

    Nonlinear Optics has continued to develop over the last few years at an extremely fast pace, with significant advances being reported in nonlinear optical metamaterials, optical signal processing, quantum optics, nonlinear optics at subwavelength scale, and biophotonics. These exciting new developments have generated significant potential for a broad spectrum of technological applications in which nonlinear-optical processes play a central role.

  5. Nonlinear Optics: Principles and Applications

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Tidemand-Lichtenberg, Peter

    As nonlinear optics further develops as a field of research in electromagnetic wave propagation, its state-of-the-art technologies will continue to strongly impact real-world applications in a variety of fields useful to the practicing scientist and engineer. From basic principles to examples...... of applications, Nonlinear Optics: Principles and Applications effectively bridges physics and mathematics with relevant applied material for real-world use. The book progresses naturally from fundamental aspects to illustrative examples, and presents a strong theoretical foundation that equips the reader...... and matter, this text focuses on the physical understanding of nonlinear optics, and explores optical material response functions in the time and frequency domain....

  6. Field guide to nonlinear optics

    CERN Document Server

    Powers, Peter E

    2013-01-01

    Optomechanics is a field of mechanics that addresses the specific design challenges associated with optical systems. This [i]Field Guide [/i]describes how to mount optical components, as well as how to analyze a given design. It is intended for practicing optical and mechanical engineers whose work requires knowledge in both optics and mechanics. This Field Guide is designed for those looking for a condensed and concise source of key concepts, equations, and techniques for nonlinear optics. Topics covered include technologically important effects, recent developments in nonlinear optics

  7. A stabilized complementarity formulation for nonlinear analysis of 3D bimodular materials

    Science.gov (United States)

    Zhang, L.; Zhang, H. W.; Wu, J.; Yan, B.

    2016-06-01

    Bi-modulus materials with different mechanical responses in tension and compression are often found in civil, composite, and biological engineering. Numerical analysis of bimodular materials is strongly nonlinear and convergence is usually a problem for traditional iterative schemes. This paper aims to develop a stabilized computational method for nonlinear analysis of 3D bimodular materials. Based on the parametric variational principle, a unified constitutive equation of 3D bimodular materials is proposed, which allows the eight principal stress states to be indicated by three parametric variables introduced in the principal stress directions. The original problem is transformed into a standard linear complementarity problem (LCP) by the parametric virtual work principle and a quadratic programming algorithm is developed by solving the LCP with the classic Lemke's algorithm. Update of elasticity and stiffness matrices is avoided and, thus, the proposed algorithm shows an excellent convergence behavior compared with traditional iterative schemes. Numerical examples show that the proposed method is valid and can accurately analyze mechanical responses of 3D bimodular materials. Also, stability of the algorithm is greatly improved.

  8. An Optically-Assisted 3-D Cellular Array Machine

    Science.gov (United States)

    1993-11-05

    Presented by: Physical Optics Corporation 0 Research & Development Division 20600 Gramercy Place, Suite 103 Torrance, California 90501 Principal...Computer Machine (Constructed Hardware) (Planned Hardware Design) Processing Techniques Digital Only Digital and Analog Analog Processor N/A Celular Neural

  9. Focusing optics of a parallel beam CCD optical tomography apparatus for 3D radiation gel dosimetry.

    Science.gov (United States)

    Krstajić, Nikola; Doran, Simon J

    2006-04-21

    Optical tomography of gel dosimeters is a promising and cost-effective avenue for quality control of radiotherapy treatments such as intensity-modulated radiotherapy (IMRT). Systems based on a laser coupled to a photodiode have so far shown the best results within the context of optical scanning of radiosensitive gels, but are very slow ( approximately 9 min per slice) and poorly suited to measurements that require many slices. Here, we describe a fast, three-dimensional (3D) optical computed tomography (optical-CT) apparatus, based on a broad, collimated beam, obtained from a high power LED and detected by a charged coupled detector (CCD). The main advantages of such a system are (i) an acquisition speed approximately two orders of magnitude higher than a laser-based system when 3D data are required, and (ii) a greater simplicity of design. This paper advances our previous work by introducing a new design of focusing optics, which take information from a suitably positioned focal plane and project an image onto the CCD. An analysis of the ray optics is presented, which explains the roles of telecentricity, focusing, acceptance angle and depth-of-field (DOF) in the formation of projections. A discussion of the approximation involved in measuring the line integrals required for filtered backprojection reconstruction is given. Experimental results demonstrate (i) the effect on projections of changing the position of the focal plane of the apparatus, (ii) how to measure the acceptance angle of the optics, and (iii) the ability of the new scanner to image both absorbing and scattering gel phantoms. The quality of reconstructed images is very promising and suggests that the new apparatus may be useful in a clinical setting for fast and accurate 3D dosimetry.

  10. Test target for characterizing 3D resolution of optical coherence tomography

    Science.gov (United States)

    Hu, Zhixiong; Hao, Bingtao; Liu, Wenli; Hong, Baoyu; Li, Jiao

    2014-12-01

    Optical coherence tomography (OCT) is a non-invasive 3D imaging technology which has been applied or investigated in many diagnostic fields including ophthalmology, dermatology, dentistry, cardiovasology, endoscopy, brain imaging and so on. Optical resolution is an important characteristic that can describe the quality and utility of an image acquiring system. We employ 3D printing technology to design and fabricate a test target for characterizing 3D resolution of optical coherence tomography. The test target which mimics USAF 1951 test chart was produced with photopolymer. By measuring the 3D test target, axial resolution as well as lateral resolution of a spectral domain OCT system was evaluated. For comparison, conventional microscope and surface profiler were employed to characterize the 3D test targets. The results demonstrate that the 3D resolution test targets have the potential of qualitatively and quantitatively validating the performance of OCT systems.

  11. PRONTO3D users` instructions: A transient dynamic code for nonlinear structural analysis

    Energy Technology Data Exchange (ETDEWEB)

    Attaway, S.W.; Mello, F.J.; Heinstein, M.W.; Swegle, J.W.; Ratner, J.A. [Sandia National Labs., Albuquerque, NM (United States); Zadoks, R.I. [Univ. of Texas, El Paso, TX (United States)

    1998-06-01

    This report provides an updated set of users` instructions for PRONTO3D. PRONTO3D is a three-dimensional, transient, solid dynamics code for analyzing large deformations of highly nonlinear materials subjected to extremely high strain rates. This Lagrangian finite element program uses an explicit time integration operator to integrate the equations of motion. Eight-node, uniform strain, hexahedral elements and four-node, quadrilateral, uniform strain shells are used in the finite element formulation. An adaptive time step control algorithm is used to improve stability and performance in plasticity problems. Hourglass distortions can be eliminated without disturbing the finite element solution using either the Flanagan-Belytschko hourglass control scheme or an assumed strain hourglass control scheme. All constitutive models in PRONTO3D are cast in an unrotated configuration defined using the rotation determined from the polar decomposition of the deformation gradient. A robust contact algorithm allows for the impact and interaction of deforming contact surfaces of quite general geometry. The Smooth Particle Hydrodynamics method has been embedded into PRONTO3D using the contact algorithm to couple it with the finite element method.

  12. Programmable Bidirectional Folding of Metallic Thin Films for 3D Chiral Optical Antennas.

    Science.gov (United States)

    Mao, Yifei; Zheng, Yun; Li, Can; Guo, Lin; Pan, Yini; Zhu, Rui; Xu, Jun; Zhang, Weihua; Wu, Wengang

    2017-03-10

    3D structures with characteristic lengths ranging from nanometer to micrometer scale often exhibit extraordinary optical properties, and have been becoming an extensively explored field for building new generation nanophotonic devices. Albeit a few methods have been developed for fabricating 3D optical structures, constructing 3D structures with nanometer accuracy, diversified materials, and perfect morphology is an extremely challenging task. This study presents a general 3D nanofabrication technique, the focused ion beam stress induced deformation process, which allows a programmable and accurate bidirectional folding (-70°-+90°) of various metal and dielectric thin films. Using this method, 3D helical optical antennas with different handedness, improved surface smoothness, and tunable geometries are fabricated, and the strong optical rotation effects of single helical antennas are demonstrated.

  13. Step-index optical fibre drawn from 3D printed preforms

    CERN Document Server

    CooK, Kevin; Canning, John; Chartier, Loic; Athanaze, Tristan; Hossain, Md Arafat; Han, Chunyang; Comatti, Jade-Edouard; Luo, Yanhua; Peng, Gang-Ding

    2016-01-01

    Optical fibre is drawn from a dual-head 3D printer fabricated preform made of two optically transparent plastics with a high index core (NA ~ 0.25, V > 60). The asymmetry observed in the fibre arises from asymmetry in the 3D printing process. The highly multi-mode optical fibre has losses measured by cut-back as low as {\\alpha} ~ 0.44 dB/cm in the near IR.

  14. Nonlinear optics principles and applications

    CERN Document Server

    Li, Chunfei

    2017-01-01

    This book reflects the latest advances in nonlinear optics. Besides the simple, strict mathematical deduction, it also discusses the experimental verification and possible future applications, such as the all-optical switches. It consistently uses the practical unit system throughout. It employs simple physical images, such as "light waves" and "photons" to systematically explain the main principles of nonlinear optical effects. It uses the first-order nonlinear wave equation in frequency domain under the condition of “slowly varying amplitude approximation" and the classical model of the interaction between the light and electric dipole. At the same time, it also uses the rate equations based on the energy-level transition of particle systems excited by photons and the energy and momentum conservation principles to explain the nonlinear optical phenomenon. The book is intended for researchers, engineers and graduate students in the field of the optics, optoelectronics, fiber communication, information tech...

  15. 3D reconstruction of SEM images by use of optical photogrammetry software.

    Science.gov (United States)

    Eulitz, Mona; Reiss, Gebhard

    2015-08-01

    Reconstruction of the three-dimensional (3D) surface of an object to be examined is widely used for structure analysis in science and many biological questions require information about their true 3D structure. For Scanning Electron Microscopy (SEM) there has been no efficient non-destructive solution for reconstruction of the surface morphology to date. The well-known method of recording stereo pair images generates a 3D stereoscope reconstruction of a section, but not of the complete sample surface. We present a simple and non-destructive method of 3D surface reconstruction from SEM samples based on the principles of optical close range photogrammetry. In optical close range photogrammetry a series of overlapping photos is used to generate a 3D model of the surface of an object. We adapted this method to the special SEM requirements. Instead of moving a detector around the object, the object itself was rotated. A series of overlapping photos was stitched and converted into a 3D model using the software commonly used for optical photogrammetry. A rabbit kidney glomerulus was used to demonstrate the workflow of this adaption. The reconstruction produced a realistic and high-resolution 3D mesh model of the glomerular surface. The study showed that SEM micrographs are suitable for 3D reconstruction by optical photogrammetry. This new approach is a simple and useful method of 3D surface reconstruction and suitable for various applications in research and teaching.

  16. Optically nonlinear materials

    CERN Document Server

    Whittam, A J

    2001-01-01

    susceptibility from 26 pm/V (same film without octadecanoic acid) to 40 pm/V. This increase in the second-order susceptibility occurred even though the amount of NLO-active dye was effectively diluted by the addition of the inactive octadecanoic acid. The wavelength of the absorption maximum ranged from 346-440 nm and there was direct correlation between the susceptibilities and the transparency of the films at the harmonic wavelength. Hemicyanine dyes were synthesised, with the general formulae: - (a) C sub 1 sub 8 H sub 3 sub 7 -A sup + -[CH=CH-C sub 6 H sub 4] sub x -N(CH sub 3) sub 2 I (b) C sub 1 sub 8 H sub 3 sub 7 -A sup + -[CH=CH] sub y -C sub 6 H sub 4 -N(CH sub 3) sub 2 I where A sup + is a pyridinium or isoquinolinium acceptor, and x = 1 or 2, and y = 1 or 2. The optically nonlinear dyes were investigated via the Langmuir-Blodgett (LB) technique. The dyes all produced isotherm data, with molecular areas of 22-60 A sup 2 per molecule, which are consistent with the cross-sectional areas of the chromo...

  17. Cytology 3D structure formation based on optical microscopy images

    Science.gov (United States)

    Pronichev, A. N.; Polyakov, E. V.; Shabalova, I. P.; Djangirova, T. V.; Zaitsev, S. M.

    2017-01-01

    The article the article is devoted to optimization of the parameters of imaging of biological preparations in optical microscopy using a multispectral camera in visible range of electromagnetic radiation. A model for the image forming of virtual preparations was proposed. The optimum number of layers was determined for the object scan in depth and holistic perception of its switching according to the results of the experiment.

  18. DETERMINATION OF INTERNAL STRAIN IN 3-D BRAIDED COMPOSITES USING OPTIC FIBER STRAIN SENSORS

    Institute of Scientific and Technical Information of China (English)

    YuanShenfang; HuangRui; LiXianghua; LiuXiaohui

    2004-01-01

    A reliable understanding of the properties of 3-D braided composites is of primary importance for proper utilization of these materials. A new method is introduced to study the mechanical performance of braided composite materials using embedded optic fiber sensors. Experimental research is performed to devise a method of incorporating optic fibers into a 3-D braided composite structure. The efficacy of this new testing method is evaluated on two counts. First,the optical performance of optic fibers is studied before and after incorporated into 3-D braided composites, as well as after completion of the manufacturing process for 3-D braided composites,to validate the ability of the optic fiber to survive the manufacturing process. On the other hand,the influence of incorporated optic fiber on the original braided composite is also researched by tension and compression experiments. Second, two kinds of optic fiber sensors are co-embedded into 3-D braided composites to evaluate their respective ability to measure the internal strain.Experimental results show that multiple optic fiber sensors can be co-braided into 3-D braided composites to determine their internal strain which is difficult to be fulfilled by other current existing methods.

  19. Optic flow-based vision system for autonomous 3D localization and control of small aerial vehicles

    OpenAIRE

    Kendoul, Farid; Fantoni, Isabelle; Nonami, Kenzo

    2009-01-01

    International audience; The problem considered in this paper involves the design of a vision-based autopilot for small and micro Unmanned Aerial Vehicles (UAVs). The proposed autopilot is based on an optic flow-based vision system for autonomous localization and scene mapping, and a nonlinear control system for flight control and guidance. This paper focusses on the development of a real-time 3D vision algorithm for estimating optic flow, aircraft self-motion and depth map, using a low-resolu...

  20. Electro-optical measurements of 3D-stc detectors fabricated at ITC-irst

    Energy Technology Data Exchange (ETDEWEB)

    Zoboli, Andrea [INFN and Department of ICT, University of Trento, via Sommarive, 14 - 38050 Povo di Trento (Italy)], E-mail: zoboli@dit.unitn.it; Boscardin, Maurizio [ITC-irst, Microsystems Division, via Sommarive, 18 - 38050 Povo di Trento (Italy); Bosisio, Luciano [INFN and Department of Physics, University of Trieste, via A. Valerio, 2 - 34127 Trieste (Italy); Dalla Betta, Gian-Franco [INFN and Department of ICT, University of Trento, via Sommarive, 14 - 38050 Povo di Trento (Italy); Piemonte, Claudio; Pozza, Alberto; Ronchin, Sabina; Zorzi, Nicola [ITC-irst, Microsystems Division, via Sommarive, 18 - 38050 Povo di Trento (Italy)

    2007-12-11

    In the past two years 3D silicon radiation detectors have been developed at ITC-irst (Trento, Italy). As a first step toward full 3D devices, simplified structures featuring columnar electrodes of one doping type only were fabricated. This paper reports the electro-optical characterization of 3D test diodes made with this approach. Experimental results and TCAD simulations provide good insight into the charge collection mechanism and response speed limitation of these structures.

  1. Tomographic active optical trapping of arbitrarily shaped objects by exploiting 3-D refractive index maps

    CERN Document Server

    Kim, Kyoohyun

    2016-01-01

    Optical trapping can be used to manipulate the three-dimensional (3-D) motion of spherical particles based on the simple prediction of optical forces and the responding motion of samples. However, controlling the 3-D behaviour of non-spherical particles with arbitrary orientations is extremely challenging, due to experimental difficulties and the extensive computations. Here, we achieved the real-time optical control of arbitrarily shaped particles by combining the wavefront shaping of a trapping beam and measurements of the 3-D refractive index (RI) distribution of samples. Engineering the 3-D light field distribution of a trapping beam based on the measured 3-D RI map of samples generates a light mould, which can be used to manipulate colloidal and biological samples which have arbitrary orientations and/or shapes. The present method provides stable control of the orientation and assembly of arbitrarily shaped particles without knowing a priori information about the sample geometry. The proposed method can ...

  2. Nonlinear optics: the next decade.

    Science.gov (United States)

    Kivshar, Yuri S

    2008-12-22

    This paper concludes the Focus Serial assembled of invited papers in key areas of nonlinear optics (Editors: J.M. Dudley and R.W. Boyd), and it discusses new directions for future research in this field.

  3. Characterizing the propagation of gravity waves in 3D nonlinear simulations of solar-like stars

    CERN Document Server

    Alvan, L; Brun, A S; Mathis, S; Garcia, R A

    2015-01-01

    The revolution of helio- and asteroseismology provides access to the detailed properties of stellar interiors by studying the star's oscillation modes. Among them, gravity (g) modes are formed by constructive interferences between progressive internal gravity waves (IGWs), propagating in stellar radiative zones. Our new 3D nonlinear simulations of the interior of a solar-like star allows us to study the excitation, propagation, and dissipation of these waves. The aim of this article is to clarify our understanding of the behavior of IGWs in a 3D radiative zone and to provide a clear overview of their properties. We use a method of frequency filtering that reveals the path of {individual} gravity waves of different frequencies in the radiative zone. We are able to identify the region of propagation of different waves in 2D and 3D, to compare them to the linear raytracing theory and to distinguish between propagative and standing waves (g modes). We also show that the energy carried by waves is distributed in d...

  4. 3D Printing Optical Engine for Controlling Material Microstructure

    Science.gov (United States)

    Huang, Wei-Chin; Chang, Kuang-Po; Wu, Ping-Han; Wu, Chih-Hsien; Lin, Ching-Chih; Chuang, Chuan-Sheng; Lin, De-Yau; Liu, Sung-Ho; Horng, Ji-Bin; Tsau, Fang-Hei

    Controlling the cooling rate of alloy during melting and resolidification is the most commonly used method for varying the material microstructure and consequently the resuling property. However, the cooling rate of a selective laser melting (SLM) production is restricted by a preset optimal parameter of a good dense product. The head room for locally manipulating material property in a process is marginal. In this study, we invent an Optical Engine for locally controlling material microstructure in a SLM process. It develops an invovative method to control and adjust thermal history of the solidification process to gain desired material microstucture and consequently drastically improving the quality. Process parameters selected locally for specific materials requirement according to designed characteristics by using thermal dynamic principles of solidification process. It utilize a technique of complex laser beam shape of adaptive irradiation profile to permit local control of material characteristics as desired. This technology could be useful for industrial application of medical implant, aerospace and automobile industries.

  5. A New Energy-Based Method for 3-D Finite-Element Nonlinear Flux Linkage computation of Electrical Machines

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Rasmussen, Peter Omand; Ritchie, Ewen

    2011-01-01

    This paper presents a new method for computation of the nonlinear flux linkage in 3-D finite-element models (FEMs) of electrical machines. Accurate computation of the nonlinear flux linkage in 3-D FEM is not an easy task. Compared to the existing energy-perturbation method, the new technique......-perturbation method. The new method proposed is validated using experimental results on two different permanent magnet machines....

  6. Characterization of fatigue resistance in photochromic composite materials for 3D rewritable optical memory applications

    Energy Technology Data Exchange (ETDEWEB)

    Samoylova, Elena, E-mail: Elena.Samoylova@physik.uni-muenchen.de [Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Dallari, William; Allione, Marco; Pignatelli, Francesca; Marini, Lara; Cingolani, Roberto; Diaspro, Alberto [Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Athanassiou, Athanassia, E-mail: athanassia.athanassiou@iit.it [Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Center for Biomolecular Nanotechnologies-Unile, Istituto Italiano di Tecnologia, via Barsanti, 73010 Arnesano, Lecce (Italy)

    2013-06-01

    Highlights: • Fatigue resistance of diarylethene–polymer composites was tested with optical absorption and fluorescence methods upon repetitive UV–VIS irradiation. • Significant differences in fatigue were found in different polymeric matrices and in one-photon and two-photon excitation experiments. • Several explanations for fatigue resistance of the composites are proposed based on the physico-chemical properties of the diarylethenes and polymeric matrices. -- Abstract: Fatigue resistance of the photochromic diarylethene molecules 1,2-bis[2-methylbenzo[b]thyophen-3-yl] -3,3,4,4,5,5-hexafluoro-1-cyclopentene embedded in three different acrylic polymers is studied upon multiple coloration–decoloration cycles. The resistance to photofatigue is found to be different in the three polymeric materials when one-photon excitation was used for the reversible photoconversion experiment. In particular, the photochromic molecules lose their photoisomerization ability faster if they are embedded in poly(methyl methacrylate) (PMMA) with respect to poly(ethyl methacrylate-co-methyl acrylate) (PEMMA) and poly(ethyl methacrylate) (PEMA). We propose several explanations based on the physico-chemical properties of the matrix and of the photochromic molecules. In the case of two-photon excitation, which is necessary for 3D optical writing, the fatigue resistance is found to be poorer than in the one-photon case. The accelerated photodegradation can be assigned to the non-linear nature of interaction between the polymeric composite material and light.

  7. Rapid Prototyping across the Spectrum: RF to Optical 3D Electromagnetic Structures

    Science.gov (United States)

    2015-11-17

    microbiology, surveillance, energy harvesting , defense technology as well as sensing platforms to name a few [85, 86]. The structure of materials...AFRL-RW-EG-TP-2015-002 Rapid Prototyping across the Spectrum: RF to Optical 3D Electromagnetic Structures Jeffery W. Allen Monica S. Allen Brett...11-17-2015 Interim Report Feb. 2012 – Dec. 2015 4. TITLE AND SUBTITLE Rapid Prototyping across the Spectrum: RF to Optical 3D Electromagnetic

  8. Oscillating solitons in nonlinear optics

    Indian Academy of Sciences (India)

    Lin Xiao-Gang; Liu Wen-Jun; Lei Ming

    2016-03-01

    Oscillating solitons are obtained in nonlinear optics. Analytical study of the variable coefficient nonlinear Schrödinger equation, which is used to describe the soliton propagation in those systems, is carried out using the Hirota’s bilinear method. The bilinear forms and analytic soliton solutions are derived, and the relevant properties and features of oscillating solitons are illustrated. Oscillating solitons are controlled by the reciprocal of the group velocity and Kerr nonlinearity. Results of this paper will be valuable to the study of dispersion-managed optical communication system and mode-locked fibre lasers.

  9. 3D early embryogenesis image filtering by nonlinear partial differential equations.

    Science.gov (United States)

    Krivá, Z; Mikula, K; Peyriéras, N; Rizzi, B; Sarti, A; Stasová, O

    2010-08-01

    We present nonlinear diffusion equations, numerical schemes to solve them and their application for filtering 3D images obtained from laser scanning microscopy (LSM) of living zebrafish embryos, with a goal to identify the optimal filtering method and its parameters. In the large scale applications dealing with analysis of 3D+time embryogenesis images, an important objective is a correct detection of the number and position of cell nuclei yielding the spatio-temporal cell lineage tree of embryogenesis. The filtering is the first and necessary step of the image analysis chain and must lead to correct results, removing the noise, sharpening the nuclei edges and correcting the acquisition errors related to spuriously connected subregions. In this paper we study such properties for the regularized Perona-Malik model and for the generalized mean curvature flow equations in the level-set formulation. A comparison with other nonlinear diffusion filters, like tensor anisotropic diffusion and Beltrami flow, is also included. All numerical schemes are based on the same discretization principles, i.e. finite volume method in space and semi-implicit scheme in time, for solving nonlinear partial differential equations. These numerical schemes are unconditionally stable, fast and naturally parallelizable. The filtering results are evaluated and compared first using the Mean Hausdorff distance between a gold standard and different isosurfaces of original and filtered data. Then, the number of isosurface connected components in a region of interest (ROI) detected in original and after the filtering is compared with the corresponding correct number of nuclei in the gold standard. Such analysis proves the robustness and reliability of the edge preserving nonlinear diffusion filtering for this type of data and lead to finding the optimal filtering parameters for the studied models and numerical schemes. Further comparisons consist in ability of splitting the very close objects which

  10. Nonlinear optics and organic materials

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Y.R.

    1994-07-01

    We shall consider an interesting topic relating nonlinear optics and organic materials: how nonlinear optics can be used to study organic materials. One of the main differences between linear and nonlinear responses of a medium to incoming radiation is in their symmetries. It leads to the possibility that some properties of the medium could be more sensitively probed by nonlinear, rather than linear, optical means, or vise versa. A well-known example is that some vibrational modes of a medium could be Raman-active but infrared-inactive, and would be more readily observed by Raman scattering, which is a two-photon transition process. In this paper, we shall discuss, with the help of three examples, how we can use second harmonic generation (SHG) and sum frequency generation (SFG) to obtain unique information about a material. We shall focus on thin films, surfaces, and interfaces.

  11. Nonlinear Optics and Turbulence

    Science.gov (United States)

    1992-10-01

    currently at Queen Mary College, London Patrick Dunne, (Ph.D., 1987, M.I.T., Hydrodynamic Stability, Nonlinear Waves), 1987-1988. Alecsander Dyachenko...U I I I U I I 3 9 3 V. BIOGRAPHIES A. FACULTY BRUCE BAYLY, 31, Ph.D. 1986, Princeton University. Postdoctoral visiting member 1986-88 at Courant...Caputo, A. C. Newell, and M. Shelley , "Nonlinear Wave Propagation Through a Random Medium and Soliton Tunneling", Integrable Systems and

  12. Integration of 3D anatomical data obtained by CT imaging and 3D optical scanning for computer aided implant surgery

    Directory of Open Access Journals (Sweden)

    Paoli Alessandro

    2011-02-01

    Full Text Available Abstract Background A precise placement of dental implants is a crucial step to optimize both prosthetic aspects and functional constraints. In this context, the use of virtual guiding systems has been recognized as a fundamental tool to control the ideal implant position. In particular, complex periodontal surgeries can be performed using preoperative planning based on CT data. The critical point of the procedure relies on the lack of accuracy in transferring CT planning information to surgical field through custom-made stereo-lithographic surgical guides. Methods In this work, a novel methodology is proposed for monitoring loss of accuracy in transferring CT dental information into periodontal surgical field. The methodology is based on integrating 3D data of anatomical (impression and cast and preoperative (radiographic template models, obtained by both CT and optical scanning processes. Results A clinical case, relative to a fully edentulous jaw patient, has been used as test case to assess the accuracy of the various steps concurring in manufacturing surgical guides. In particular, a surgical guide has been designed to place implants in the bone structure of the patient. The analysis of the results has allowed the clinician to monitor all the errors, which have been occurring step by step manufacturing the physical templates. Conclusions The use of an optical scanner, which has a higher resolution and accuracy than CT scanning, has demonstrated to be a valid support to control the precision of the various physical models adopted and to point out possible error sources. A case study regarding a fully edentulous patient has confirmed the feasibility of the proposed methodology.

  13. Nonlinear coupling analysis of coal seam floor during mining based on FLAC3D

    Institute of Scientific and Technical Information of China (English)

    YAO Duo-xi; XU Ji-ying; LU Hai-feng

    2011-01-01

    Based on the hydro-geological conditions of 1028 mining face in Suntuan Coal Mine, mining seepage strain mechanism of seam floor was simulated by a nonlinear coupling method, which applied fluid-solid coupling analysis module of FLAC3D. The results indicate that the permeability coefficient of adjoining rock changes a lot due to mining. The maximum value reaches 1 379.9 times to the original value, where it is at immediate roof of the mined-out area. According to the analysis on the seepage field, mining does not destroy water resistance of the floor aquiclude. The mining fissure does not conduct lime-stone aquifer, and it is less likely to form damage. The plastic zone does not exactly correspond to the seepage area, and the scope of the altered seepage area is much larger than the plastic zone.

  14. Corotational formulation for 3d solids. An analysis of geometrically nonlinear foam deformation

    CERN Document Server

    Kaczmarczyk, Łukasz; Pearce, Chris J

    2011-01-01

    This paper presents theory for the Lagrange co-rotational (CR) formulation of finite elements in the geometrically nonlinear analysis of 3D structures. In this paper strains are assumed to be small while the magnitude of rotations from the reference configuration is not restricted. A new best fit rotator and consistent spin filter are derived. Lagrange CR formulation is applied with Hybrid Trefftz Stress elements, although presented methodology can be applied to arbitrary problem formulation and discretization technique, f.e. finite volume methods and lattice models, discreet element methods. Efficiency of CR formulation can be utilized in post-buckling stability analysis, damage and fracture mechanics, modelling of dynamic fragmentation of bodies made from quasi-brittle materials, solid fluid interactions and analysis of post-stressed structures, discreet body dynamics.

  15. 3D Nonlinear Numerical Simulation of Intact and Debonded Reinforced Concrete Beams

    Institute of Scientific and Technical Information of China (English)

    Chen Quan(陈权); Marcus L.

    2004-01-01

    To study the behaviour of reinforced concrete (RC) structures with sections of concrete removed and the reinforcement exposed, 3D nonlinear numerical analysis was performed upon both intact and debonded RC beams by using finite element techniques. The deformational characteristics and the ultimate loads were obtained through numerical models, as well as crack and stress distributions. The failure modes can also be deduced from computational results. Compared with intact beams, the normal assumptions of plane section behaviour is not hold true and the patterns of stress and strain are different in debonded RC beams. The numerical results show good consistency with experimental data. This kind of numerical simulation is a supplement to existing codes.

  16. The Singularity Threshold of the Nonlinear Sigma Model Using 3D Adaptive Mesh Refinement

    CERN Document Server

    Liebling, S L

    2002-01-01

    Numerical solutions to the nonlinear sigma model (NLSM), a wave map from 3+1 Minkowski space to S^3, are computed in three spatial dimensions (3D) using adaptive mesh refinement (AMR). For initial data with compact support the model is known to have two regimes, one in which regular initial data forms a singularity and another in which the energy is dispersed to infinity. The transition between these regimes has been shown in spherical symmetry to demonstrate threshold behavior similar to that between black hole formation and dispersal in gravitating theories. Here, I generalize the result by removing the assumption of spherical symmetry. The evolutions suggest that the spherically symmetric critical solution remains an intermediate attractor separating the two end states.

  17. New nonlinear optical materials based on ferrofluids

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J P [Department of Physics, Fudan University, Shanghai 200433 (China); Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Institute of Theoretical Physics, Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); Yu, K W [Department of Physics, Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); Institute of Theoretical Physics, Chinese University of Hong Kong, Shatin, NT, Hong Kong (China)

    2006-01-01

    We exploit theoretically a new class of magneto-controlled nonlinear optical material based on ferrofluids in which ferromagnetic nanoparticles are coated with a nonmagnetic metallic nonlinear shell. Such an optical material can have anisotropic nonlinear optical properties and a giant enhancement of nonlinearity, as well as an attractive figure of merit.

  18. Threshold response using modulated continuous wave illumination for multilayer 3D optical data storage

    Science.gov (United States)

    Saini, A.; Christenson, C. W.; Khattab, T. A.; Wang, R.; Twieg, R. J.; Singer, K. D.

    2017-01-01

    In order to achieve a high capacity 3D optical data storage medium, a nonlinear or threshold writing process is necessary to localize data in the axial dimension. To this end, commercial multilayer discs use thermal ablation of metal films or phase change materials to realize such a threshold process. This paper addresses a threshold writing mechanism relevant to recently reported fluorescence-based data storage in dye-doped co-extruded multilayer films. To gain understanding of the essential physics, single layer spun coat films were used so that the data is easily accessible by analytical techniques. Data were written by attenuating the fluorescence using nanosecond-range exposure times from a 488 nm continuous wave laser overlapping with the single photon absorption spectrum. The threshold writing process was studied over a range of exposure times and intensities, and with different fluorescent dyes. It was found that all of the dyes have a common temperature threshold where fluorescence begins to attenuate, and the physical nature of the thermal process was investigated.

  19. Combining 3D optical imaging and dual energy absorptiometry to measure three compositional components

    Science.gov (United States)

    Malkov, Serghei; Shepherd, John

    2014-02-01

    We report on the design of the technique combining 3D optical imaging and dual-energy absorptiometry body scanning to estimate local body area compositions of three compartments. Dual-energy attenuation and body shape measures are used together to solve for the three compositional tissue thicknesses: water, lipid, and protein. We designed phantoms with tissue-like properties as our reference standards for calibration purposes. The calibration was created by fitting phantom values using non-linear regression of quadratic and truncated polynomials. Dual-energy measurements were performed on tissue-mimicking phantoms using a bone densitometer unit. The phantoms were made of materials shown to have similar x-ray attenuation properties of the biological compositional compartments. The components for the solid phantom were tested and their high energy/low energy attenuation ratios are in good correspondent to water, lipid, and protein for the densitometer x-ray region. The three-dimensional body shape was reconstructed from the depth maps generated by Microsoft Kinect for Windows. We used open-source Point Cloud Library and freeware software to produce dense point clouds. Accuracy and precision of compositional and thickness measures were calculated. The error contributions due to two modalities were estimated. The preliminary phantom composition and shape measurements are found to demonstrate the feasibility of the method proposed.

  20. Terahertz semiconductor nonlinear optics

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias

    2013-01-01

    nonlinearity in doped semiconductors originates from the near-instantaneous heating of free electrons in the ponderomotive potential created by electric field of the THz pulse, leading to ultrafast increase of electron effective mass by intervalley scattering. Modification of effective mass in turn leads...

  1. Resource Letter NO-1: Nonlinear Optics

    Science.gov (United States)

    Garmire, Elsa

    2011-03-01

    This Resource Letter provides a guide to the literature on nonlinear optics. Books, journals, and websites are introduced that cover the general subject. Journal articles and websites are cited covering the following topics: second-order nonlinearities in transparent media including second-harmonic generation and optical parametric oscillation, third-order and higher nonlinearities, nonlinear refractive index, absorptive nonlinearities such as saturable absorption and multiphoton absorption, and scattering nonlinearities such as stimulated Raman scattering and stimulated Brillouin scattering. Steady-state and transient phenomena, fiber optics, solitons, nonlinear wave mixing, optical phase conjugation, nonlinear spectroscopy, and multiphoton microscopy are all outlined.

  2. Progress in nonlinear nano-optics

    CERN Document Server

    Lienau, Christoph; Grunwald, Rüdiger

    2015-01-01

    This book presents the state of the art in nonlinear nanostructures for ultrafast laser applications. Most recent results in two emerging fields are presented: (i) generation of laser-induced nanostructures in materials like metals, metal oxides and semiconductors, and (ii) ultrafast excitation and energy transfer in nanoscale physical, chemical and hybrid systems. Particular emphasis is laid on the up-to-date controversially discussed mechanisms of sub-wavelength ripple formation including models of self-organized material transport and multiphoton excitation channels, nonlinear optics of plasmonic structures (nanotips, nanowires, 3D-metamaterials), and energy localization and transport on ultrafast time scale and spatial nanoscale. High-resolution spectroscopy, simulation and characterization techniques are reported. New applications of ultrashort-pulsed lasers for materials processing and the use of nanostructured materials for characterizing laser fields and laser-matter-interactions are discussed.

  3. Nanoimprint of a 3D structure on an optical fiber for light wavefront manipulation

    Science.gov (United States)

    Calafiore, Giuseppe; Koshelev, Alexander; Allen, Frances I.; Dhuey, Scott; Sassolini, Simone; Wong, Edward; Lum, Paul; Munechika, Keiko; Cabrini, Stefano

    2016-09-01

    Integration of complex photonic structures onto optical fiber facets enables powerful platforms with unprecedented optical functionalities. Conventional nanofabrication technologies, however, do not permit viable integration of complex photonic devices onto optical fibers owing to their low throughput and high cost. In this paper we report the fabrication of a three-dimensional structure achieved by direct nanoimprint lithography on the facet of an optical fiber. Nanoimprint processes and tools were specifically developed to enable a high lithographic accuracy and coaxial alignment of the optical device with respect to the fiber core. To demonstrate the capability of this new approach, a 3D beam splitter has been designed, imprinted and optically characterized. Scanning electron microscopy and optical measurements confirmed the good lithographic capabilities of the proposed approach as well as the desired optical performance of the imprinted structure. The inexpensive solution presented here should enable advancements in areas such as integrated optics and sensing, achieving enhanced portability and versatility of fiber optic components.

  4. Nanoimprint of a 3D structure on an optical fiber for light wavefront manipulation.

    Science.gov (United States)

    Calafiore, Giuseppe; Koshelev, Alexander; Allen, Frances I; Dhuey, Scott; Sassolini, Simone; Wong, Edward; Lum, Paul; Munechika, Keiko; Cabrini, Stefano

    2016-09-16

    Integration of complex photonic structures onto optical fiber facets enables powerful platforms with unprecedented optical functionalities. Conventional nanofabrication technologies, however, do not permit viable integration of complex photonic devices onto optical fibers owing to their low throughput and high cost. In this paper we report the fabrication of a three-dimensional structure achieved by direct nanoimprint lithography on the facet of an optical fiber. Nanoimprint processes and tools were specifically developed to enable a high lithographic accuracy and coaxial alignment of the optical device with respect to the fiber core. To demonstrate the capability of this new approach, a 3D beam splitter has been designed, imprinted and optically characterized. Scanning electron microscopy and optical measurements confirmed the good lithographic capabilities of the proposed approach as well as the desired optical performance of the imprinted structure. The inexpensive solution presented here should enable advancements in areas such as integrated optics and sensing, achieving enhanced portability and versatility of fiber optic components.

  5. Design of extended viewing zone at autostereoscopic 3D display based on diffusing optical element

    Science.gov (United States)

    Kim, Min Chang; Hwang, Yong Seok; Hong, Suk-Pyo; Kim, Eun Soo

    2012-03-01

    In this paper, to realize a non-glasses type 3D display as next step from the current glasses-typed 3D display, it is suggested that a viewing zone is designed for the 3D display using DOE (Diffusing Optical Element). Viewing zone of proposed method is larger than that of the current parallax barrier method or lenticular method. Through proposed method, it is shown to enable the expansion and adjustment of the area of viewing zone according to viewing distance.

  6. 3D printing optical watermark algorithms based on the combination of DWT and Fresnel transformation

    Science.gov (United States)

    Hu, Qi; Duan, Jin; Zhai, Di; Wang, LiNing

    2016-10-01

    With the continuous development of industrialization, 3D printing technology steps into individuals' lives gradually, however, the consequential security issue has become the urgent problem which is imminent. This paper proposes the 3D printing optical watermark algorithms based on the combination of DWT and Fresnel transformation and utilizes authorized key to restrict 3D model printing's permissions. Firstly, algorithms put 3D model into affine transform, and take the distance from the center of gravity to the vertex of 3D object in order to generate a one-dimensional discrete signal; then make this signal into wavelet transform and put the transformed coefficient into Fresnel transformation. Use math model to embed watermark information into it and finally generate 3D digital model with watermarking. This paper adopts VC++.NET and DIRECTX 9.0 SDK for combined developing and testing, and the results show that in fixed affine space, achieve the robustness in translation, revolving and proportion transforms of 3D model and better watermark-invisibility. The security and authorization of 3D model have been protected effectively.

  7. Large core plastic planar optical splitter fabricated by 3D printing technology

    Science.gov (United States)

    Prajzler, Václav; Kulha, Pavel; Knietel, Marian; Enser, Herbert

    2017-10-01

    We report on the design, fabrication and optical properties of large core multimode optical polymer splitter fabricated using fill up core polymer in substrate that was made by 3D printing technology. The splitter was designed by the beam propagation method intended for assembling large core waveguide fibers with 735 μm diameter. Waveguide core layers were made of optically clear liquid adhesive, and Veroclear polymer was used as substrate and cover layers. Measurement of optical losses proved that the insertion optical loss was lower than 6.8 dB in the visible spectrum.

  8. Design, Simulation and Optimisation of a Fibre-optic 3D Accelerometer

    Science.gov (United States)

    Yang, Zhen; Fang, Xiao-Yong; Zhou, Yan; Li, Ya-lin; Yuan, Jie; Cao, Mao-Sheng

    2013-07-01

    Using an inertia pendulum comprised of two prisms, flexible beams and an elastic flake, we present a novel fibre-optic 3D accelerometer design. The total reverse reflection of the cube-corner prism and the spectroscopic property of an orthogonal holographic grating enable the measurement of the two transverse components of the 3D acceleration simultaneously, while the longitudinal component can be determined from the elastic deformation of the flake. Due to optical interferometry, this sensor may provide a wider range, higher sensitivity and better resolving power than other accelerometers. Moreover, we use finite element analysis to study the performance and to optimise the structural design of the sensor.

  9. Nonlinear Optics of Hexaphenyl Nanofibers

    DEFF Research Database (Denmark)

    Balzer, Frank; Al-Shamery, Katharina; Neuendorf, Rolf

    2003-01-01

    measurements reveal that the nonlinear optical transition dipole moment is oriented with an angle of 75° with respect to the needles long axes. The absolute value of the macroscopic second-order susceptibility, averaged over a size distribution of p-6P nanoaggregates, is estimated to be of the order of 6...

  10. Analysis and adaptive synchronization of eight-term 3-D polynomial chaotic systems with three quadratic nonlinearities

    Science.gov (United States)

    Vaidyanathan, S.

    2014-06-01

    This paper proposes a eight-term 3-D polynomial chaotic system with three quadratic nonlinearities and describes its properties. The maximal Lyapunov exponent (MLE) of the proposed 3-D chaotic system is obtained as L 1 = 6.5294. Next, new results are derived for the global chaos synchronization of the identical eight-term 3-D chaotic systems with unknown system parameters using adaptive control. Lyapunov stability theory has been applied for establishing the adaptive synchronization results. Numerical simulations are shown using MATLAB to describe the main results derived in this paper.

  11. Deformation analysis of 3D tagged cardiac images using an optical flow method

    Directory of Open Access Journals (Sweden)

    Gorman Robert C

    2010-03-01

    Full Text Available Abstract Background This study proposes and validates a method of measuring 3D strain in myocardium using a 3D Cardiovascular Magnetic Resonance (CMR tissue-tagging sequence and a 3D optical flow method (OFM. Methods Initially, a 3D tag MR sequence was developed and the parameters of the sequence and 3D OFM were optimized using phantom images with simulated deformation. This method then was validated in-vivo and utilized to quantify normal sheep left ventricular functions. Results Optimizing imaging and OFM parameters in the phantom study produced sub-pixel root-mean square error (RMS between the estimated and known displacements in the x (RMSx = 0.62 pixels (0.43 mm, y (RMSy = 0.64 pixels (0.45 mm and z (RMSz = 0.68 pixels (1 mm direction, respectively. In-vivo validation demonstrated excellent correlation between the displacement measured by manually tracking tag intersections and that generated by 3D OFM (R ≥ 0.98. Technique performance was maintained even with 20% Gaussian noise added to the phantom images. Furthermore, 3D tracking of 3D cardiac motions resulted in a 51% decrease in in-plane tracking error as compared to 2D tracking. The in-vivo function studies showed that maximum wall thickening was greatest in the lateral wall, and increased from both apex and base towards the mid-ventricular region. Regional deformation patterns are in agreement with previous studies on LV function. Conclusion A novel method was developed to measure 3D LV wall deformation rapidly with high in-plane and through-plane resolution from one 3D cine acquisition.

  12. Internal Strain Measurement in 3D Braided Composites Using Co-braided Optical Fiber Sensors

    Institute of Scientific and Technical Information of China (English)

    Shenfang YUAN; Rui HUANG; Yunjiang RAO

    2004-01-01

    3D braided composite technology has stimulated a great deal of interest in the world at large. But due to the threedimensional nature of these kinds of composites, coupled with the shortcomings of currently-adopted experimental test methods, it is difficult to measure the internal parameters of this materials, hence causes it difficult to understand the material performance. A new method is introduced herein to measure the internal strain of braided composite materials using co-braided fiber optic sensors. Two kinds of fiber optic sensors are co-braided into 3D braided composites to measure internal strain. One of these is the Fabry-Parrot (F-P) fiber optic sensor; the other is the polarimetric fiber optic sensor. Experiments are conducted to measure internal strain under tension, bending and thermal environments in the 3D carbon fiber braided composite specimens, both locally and globally. Experimental results show that multiple fiber optic sensors can be braided into the 3D braided composites to measure the internal parameters, providing a more accurate measurement method and leading to a better understanding of these materials.

  13. Target Tracking in 3-D Using Estimation Based Nonlinear Control Laws for UAVs

    Directory of Open Access Journals (Sweden)

    Mousumi Ahmed

    2016-02-01

    Full Text Available This paper presents an estimation based backstepping like control law design for an Unmanned Aerial Vehicle (UAV to track a moving target in 3-D space. A ground-based sensor or an onboard seeker antenna provides range, azimuth angle, and elevation angle measurements to a chaser UAV that implements an extended Kalman filter (EKF to estimate the full state of the target. A nonlinear controller then utilizes this estimated target state and the chaser’s state to provide speed, flight path, and course/heading angle commands to the chaser UAV. Tracking performance with respect to measurement uncertainty is evaluated for three cases: (1 stationary white noise; (2 stationary colored noise and (3 non-stationary (range correlated white noise. Furthermore, in an effort to improve tracking performance, the measurement model is made more realistic by taking into consideration range-dependent uncertainties in the measurements, i.e., as the chaser closes in on the target, measurement uncertainties are reduced in the EKF, thus providing the UAV with more accurate control commands. Simulation results for these cases are shown to illustrate target state estimation and trajectory tracking performance.

  14. A novel 3-D jerk chaotic system with three quadratic nonlinearities and its adaptive control

    Directory of Open Access Journals (Sweden)

    Vaidyanathan Sundarapandian

    2016-03-01

    Full Text Available This paper announces an eight-term novel 3-D jerk chaotic system with three quadratic nonlinearities. The phase portraits of the novel jerk chaotic system are displayed and the qualitative properties of the jerk system are described. The novel jerk chaotic system has two equilibrium points, which are saddle-foci and unstable. The Lyapunov exponents of the novel jerk chaotic system are obtained as L1 = 0.20572,L2 = 0 and L3 = −1.20824. Since the sum of the Lyapunov exponents of the jerk chaotic system is negative, we conclude that the chaotic system is dissipative. The Kaplan-Yorke dimension of the novel jerk chaotic system is derived as DKY = 2.17026. Next, an adaptive controller is designed via backstepping control method to globally stabilize the novel jerk chaotic system with unknown parameters. Moreover, an adaptive controller is also designed via backstepping control method to achieve global chaos synchronization of the identical jerk chaotic systems with unknown parameters. The backstepping control method is a recursive procedure that links the choice of a Lyapunov function with the design of a controller and guarantees global asymptotic stability of strict feedback systems. MATLAB simulations have been depicted to illustrate the phase portraits of the novel jerk chaotic system and also the adaptive backstepping control results.

  15. Nonlinear 3-D simulation of high-intensity focused ultrasound therapy in the kidney

    CERN Document Server

    Suomi, Visa; Treeby, Bradley; Cleveland, Robin

    2016-01-01

    Kidney cancer is a severe disease which can be treated non-invasively using high-intensity focused ultrasound (HIFU) therapy. However, tissue in front of the transducer and the deep location of kidney can cause significant losses to the efficiency of the treatment. The effect of attenuation, refraction and reflection due to different tissue types on HIFU therapy of the kidney was studied using a nonlinear ultrasound simulation model. The geometry of the tissue was derived from a computed tomography (CT) dataset of a patient which had been segmented for water, bone, soft tissue, fat and kidney. The combined effect of inhomogeneous attenuation and sound-speed was found to result in an 11.0 dB drop in spatial peak-temporal average (SPTA) intensity in the kidney compared to pure water. The simulation without refraction effects showed a 6.3 dB decrease indicating that both attenuation and refraction contribute to the loss in focal intensity. The losses due to reflections at soft tissue interfaces were less than 0....

  16. Reconstruction of 3D refractive index profiles of PM PANDA optical fiber using digital holographic method

    Science.gov (United States)

    Wahba, H. H.

    2014-10-01

    In this paper, the refractive indices distributions on the two birefringent axes of polarization maintaining (PM) PANDA type optical fiber are reconstructed. The local refraction of the incident rays crossing the PM optical fiber is considered. Off-axis digital holographic interferometric phase shifting arrangement is employed in this investigation. The recorded mutual phase shifted holograms, starts with 0° with steps of π/4, are combined and numerically reconstructed in the image plane to obtain the optical interference phase map. Consequently, the optical phase differences due to the PM optical fiber are extracted after unwrapping and background subtraction of the enhanced optical interference phase map. The birefringence and the beat length in the two directions, fast and slow axes of PM optical fiber, of polarizations in the core region are calculated. This holographic technique and the advanced analysis of the phase shifting permit the calculation of the 3D refractive index distributions for PM PANDA optical fiber.

  17. Nanoimprint of a 3D structure on an optical fiber for light wavefront manipulation

    CERN Document Server

    Calafiore, Giuseppe; Allen, Frances I; Dhuey, Scott; Sassolini, Simone; Wong, Edward; Lum, Paul; Munechika, Keiko; Cabrini, Stefano

    2016-01-01

    Integration of complex photonic structures onto optical fiber facets enables powerful platforms with unprecedented optical functionalities. Conventional nanofabrication technologies, however, do not permit viable integration of complex photonic devices onto optical fibers owing to their low throughput and high cost. In this paper we report the fabrication of a three dimensional structure achieved by direct Nanoimprint Lithography on the facet of an optical fiber. Nanoimprint processes and tools were specifically developed to enable a high lithographic accuracy and coaxial alignment of the optical device with respect to the fiber core. To demonstrate the capability of this new approach, a 3D beam splitter has been designed, imprinted and optically characterized. Scanning electron microscopy and optical measurements confirmed the excellent lithographic capabilities of the proposed approach as well as the desired optical performance of the imprinted structure. The inexpensive solution presented here should enabl...

  18. 3D mapping of elastic modulus using shear wave optical micro-elastography

    Science.gov (United States)

    Zhu, Jiang; Qi, Li; Miao, Yusi; Ma, Teng; Dai, Cuixia; Qu, Yueqiao; He, Youmin; Gao, Yiwei; Zhou, Qifa; Chen, Zhongping

    2016-10-01

    Elastography provides a powerful tool for histopathological identification and clinical diagnosis based on information from tissue stiffness. Benefiting from high resolution, three-dimensional (3D), and noninvasive optical coherence tomography (OCT), optical micro-elastography has the ability to determine elastic properties with a resolution of ~10 μm in a 3D specimen. The shear wave velocity measurement can be used to quantify the elastic modulus. However, in current methods, shear waves are measured near the surface with an interference of surface waves. In this study, we developed acoustic radiation force (ARF) orthogonal excitation optical coherence elastography (ARFOE-OCE) to visualize shear waves in 3D. This method uses acoustic force perpendicular to the OCT beam to excite shear waves in internal specimens and uses Doppler variance method to visualize shear wave propagation in 3D. The measured propagation of shear waves agrees well with the simulation results obtained from finite element analysis (FEA). Orthogonal acoustic excitation allows this method to measure the shear modulus in a deeper specimen which extends the elasticity measurement range beyond the OCT imaging depth. The results show that the ARFOE-OCE system has the ability to noninvasively determine the 3D elastic map.

  19. Monocular accommodation condition in 3D display types through geometrical optics

    Science.gov (United States)

    Kim, Sung-Kyu; Kim, Dong-Wook; Park, Min-Chul; Son, Jung-Young

    2007-09-01

    Eye fatigue or strain phenomenon in 3D display environment is a significant problem for 3D display commercialization. The 3D display systems like eyeglasses type stereoscopic or auto-stereoscopic multiview, Super Multi-View (SMV), and Multi-Focus (MF) displays are considered for detail calculation about satisfaction level of monocular accommodation by geometrical optics calculation means. A lens with fixed focal length is used for experimental verification about numerical calculation of monocular defocus effect caused by accommodation at three different depths. And the simulation and experiment results consistently show relatively high level satisfaction about monocular accommodation at MF display condition. Additionally, possibility of monocular depth perception, 3D effect, at monocular MF display is discussed.

  20. 3D automatic quantification applied to optically sectioned images to improve microscopy analysis

    Directory of Open Access Journals (Sweden)

    JE Diaz-Zamboni

    2009-08-01

    Full Text Available New fluorescence microscopy techniques, such as confocal or digital deconvolution microscopy, allow to easily obtain three-dimensional (3D information from specimens. However, there are few 3D quantification tools that allow extracting information of these volumes. Therefore, the amount of information acquired by these techniques is difficult to manipulate and analyze manually. The present study describes a model-based method, which for the first time shows 3D visualization and quantification of fluorescent apoptotic body signals, from optical serial sections of porcine hepatocyte spheroids correlating them to their morphological structures. The method consists on an algorithm that counts apoptotic bodies in a spheroid structure and extracts information from them, such as their centroids in cartesian and radial coordinates, relative to the spheroid centre, and their integrated intensity. 3D visualization of the extracted information, allowed us to quantify the distribution of apoptotic bodies in three different zones of the spheroid.

  1. Nonlinear fiber optics formerly quantum electronics

    CERN Document Server

    Agrawal, Govind

    1995-01-01

    The field of nonlinear fiber optics has grown substantially since the First Edition of Nonlinear Fiber Optics, published in 1989. Like the First Edition, this Second Edition is a comprehensive, tutorial, and up-to-date account of nonlinear optical phenomena in fiber optics. It synthesizes widely scattered research material and presents it in an accessible manner for students and researchers already engaged in or wishing to enter the field of nonlinear fiber optics. Particular attention is paid to the importance of nonlinear effects in the design of optical fiber communication systems. This is

  2. Bone tissue phantoms for optical flowmeters at large interoptode spacing generated by 3D-stereolithography.

    Science.gov (United States)

    Binzoni, Tiziano; Torricelli, Alessandro; Giust, Remo; Sanguinetti, Bruno; Bernhard, Paul; Spinelli, Lorenzo

    2014-08-01

    A bone tissue phantom prototype allowing to test, in general, optical flowmeters at large interoptode spacings, such as laser-Doppler flowmetry or diffuse correlation spectroscopy, has been developed by 3D-stereolithography technique. It has been demonstrated that complex tissue vascular systems of any geometrical shape can be conceived. Absorption coefficient, reduced scattering coefficient and refractive index of the optical phantom have been measured to ensure that the optical parameters reasonably reproduce real human bone tissue in vivo. An experimental demonstration of a possible use of the optical phantom, utilizing a laser-Doppler flowmeter, is also presented.

  3. Changes in quantitative 3D shape features of the optic nerve head associated with age

    Science.gov (United States)

    Christopher, Mark; Tang, Li; Fingert, John H.; Scheetz, Todd E.; Abramoff, Michael D.

    2013-02-01

    Optic nerve head (ONH) structure is an important biological feature of the eye used by clinicians to diagnose and monitor progression of diseases such as glaucoma. ONH structure is commonly examined using stereo fundus imaging or optical coherence tomography. Stereo fundus imaging provides stereo views of the ONH that retain 3D information useful for characterizing structure. In order to quantify 3D ONH structure, we applied a stereo correspondence algorithm to a set of stereo fundus images. Using these quantitative 3D ONH structure measurements, eigen structures were derived using principal component analysis from stereo images of 565 subjects from the Ocular Hypertension Treatment Study (OHTS). To evaluate the usefulness of the eigen structures, we explored associations with the demographic variables age, gender, and race. Using regression analysis, the eigen structures were found to have significant (p glaucoma, disease progression and outcomes, and genetic factors.

  4. Unsymmetrical squaraines for nonlinear optical materials

    Science.gov (United States)

    Marder, Seth R. (Inventor); Chen, Chin-Ti (Inventor); Cheng, Lap-Tak (Inventor)

    1996-01-01

    Compositions for use in non-linear optical devices. The compositions have first molecular electronic hyperpolarizability (.beta.) either positive or negative in sign and therefore display second order non-linear optical properties when incorporated into non-linear optical devices.

  5. Single Camera 3-D Coordinate Measuring System Based on Optical Probe Imaging

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new vision coordinate measuring system——single camera 3-D coordinate measuring system based on optical probe imaging is presented. A new idea in vision coordinate measurement is proposed. A linear model is deduced which can distinguish six freedom degrees of optical probe to realize coordinate measurement of the object surface. The effects of some factors on the resolution of the system are analyzed. The simulating experiments have shown that the system model is available.

  6. Fiber Optic 3-D Space Piezoelectric Accelerometer and its Antinoise Technology

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The mechanical structure of piezoelectric accelerometer is designed, and the operation equations on X-, Y-, and Z-axes are deduced. The test results of 3-D frequency response are given. Noise disturbances are effectively eliminated by using fiber optic transmission and synchronous detection.

  7. 3-D printed sensing patches with embedded polymer optical fibre Bragg gratings

    DEFF Research Database (Denmark)

    Zubel, Michal G.; Sugden, Kate; Saez-Rodriguez, D.

    2016-01-01

    The first demonstration of a polymer optical fibre Bragg grating (POFBG) embedded in a 3-D printed structure is reported. Its cyclic strain performance and temperature characteristics are examined and discussed. The sensing patch has a repeatable strain sensitivity of 0.38 pm/mu epsilon. Its...

  8. Rewritable 3D bit optical data storage in a PMMA-based photorefractive polymer

    Energy Technology Data Exchange (ETDEWEB)

    Day, D.; Gu, M. [Swinburne Univ. of Tech., Hawthorn, Vic. (Australia). Centre for Micro-Photonics; Smallridge, A. [Victoria Univ., Melbourne (Australia). School of Life Sciences and Technology

    2001-07-04

    A cheap, compact, and rewritable high-density optical data storage system for CD and DVD applications is presented by the authors. Continuous-wave illumination under two-photon excitation in a new poly(methylmethacrylate) (PMMA) based photorefractive polymer allows 3D bit storage of sub-Tbyte data. (orig.)

  9. GEOMETRIC OPTICS FOR 3D-HARTREE-TYPE EQUATION WITH COULOMB POTENTIAL

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This article considers a family of 3D-Hartree-type equation with Coulomb potential |x|-1, whose initial data oscillates so that a caustic appears. In the linear geometric optics case, by using the Lagrangian integrals, a uniform description of the solution outside the caustic, and near the caustic are obtained.

  10. 3D tomographic breast imaging in-vivo using a handheld optical imager

    Science.gov (United States)

    Erickson, Sarah J.; Martinez, Sergio; Gonzalez, Jean; Roman, Manuela; Nunez, Annie; Godavarty, Anuradha

    2011-02-01

    Hand-held optical imagers are currently developed toward clinical imaging of breast tissue. However, the hand-held optical devices developed to are not able to coregister the image to the tissue geometry for 3D tomography. We have developed a hand-held optical imager which has demonstrated automated coregistered imaging and 3D tomography in phantoms, and validated coregistered imaging in normal human subjects. Herein, automated coregistered imaging is performed in a normal human subject with a 0.45 cm3 spherical target filled with 1 μM indocyanine green (fluorescent contrast agent) placed superficially underneath the flap of the breast tissue. The coregistered image data is used in an approximate extended Kalman filter (AEKF) based reconstruction algorithm to recover the 3D location of the target within the breast tissue geometry. The results demonstrate the feasibility of performing 3D tomographic imaging and recovering a fluorescent target in breast tissue of a human subject for the first time using a hand-held based optical imager. The significance of this work is toward clinical imaging of breast tissue for cancer diagnostics and therapy monitoring.

  11. Coordinates calibration in precision detection of 3D optical deformation measurement system

    Science.gov (United States)

    Lu, Honggang; Hu, Chunsheng; Wang, Xingshu; Gao, Yang; Wu, Wei

    2012-11-01

    In order to validate the detection precision of a three Dimensions Optical Deformation Measure System (3D-OMS), a calibration method of auxiliary coordinate and the optical coordinate base on theodolites has been proposed. The installation method by using theodolites to calibrate the auxiliary coordinate and the optical coordinate has been proposed. Specifically, after the auxiliary mirrors installed, the installation accuracy is detected, then we analyzed the influence of Axis-Error of theodolite under the practical condition of our experiment. Furthermore, the influence of validation precision for the 3D-OMS caused by the misalignment of auxiliary coordinate and optical coordinate is analyzed. According to our theoretical analysis and experiments results, the validation precision of the 3D-OMS can achieve an accuracy of 1″ at the conditions of the coordinate alignment accuracy is no more than 10' and the measuring range of 3D-OMS within +/-3'. Therefore, the proposed method can meet our high accuracy requirement while not sensitive to the installation error of auxiliary mirrors. This method is also available for other similar work.

  12. 3-D printed sensing patches with embedded polymer optical fibre Bragg gratings

    DEFF Research Database (Denmark)

    Zubel, Michal G.; Sugden, Kate; Saez-Rodriguez, D.;

    2016-01-01

    The first demonstration of a polymer optical fibre Bragg grating (POFBG) embedded in a 3-D printed structure is reported. Its cyclic strain performance and temperature characteristics are examined and discussed. The sensing patch has a repeatable strain sensitivity of 0.38 pm/mu epsilon. Its temp...

  13. 3D optical vortices generated by micro-optical elements and its novel applications

    Institute of Scientific and Technical Information of China (English)

    BU J.; LIN J.; K. J. Moh; B. P. S. Ahluwalia; CHEN H. L.; PENG X.; NIU H. B.; YUAN X.C.

    2007-01-01

    In this paper we report on recent development in the areas of optical vortices generated by micro-optical elements and applications of optical vortices, including optical manipulation, radial polarization and secure free space optical communication

  14. 3D optical coherence tomography super pixel with machine classifier analysis for glaucoma detection.

    Science.gov (United States)

    Xu, Juan; Ishikawa, Hiroshi; Wollstein, Gadi; Schuman, Joel S

    2011-01-01

    Current standard quantitative 3D spectral-domain optical coherence tomography (SD-OCT) analyses of various ocular diseases is limited in detecting structural damage at early pathologic stages. This is mostly because only a small fraction of the 3D data is used in the current method of quantifying the structure of interest. This paper presents a novel SD-OCT data analysis technique, taking full advantage of the 3D dataset. The proposed algorithm uses machine classifier to analyze SD-OCT images after grouping adjacent pixels into super pixel in order to detect glaucomatous damage. A 3D SD-OCT image is first converted into a 2D feature map and partitioned into over a hundred super pixels. Machine classifier analysis using boosting algorithm is performed on super pixel features. One hundred and ninety-two 3D OCT images of the optic nerve head region were tested. Area under the receiver operating characteristic (AUC) was computed to evaluate the glaucoma discrimination performance of the algorithm and compare it to the commercial software output. The AUC of normal vs glaucoma suspect eyes using the proposed method was statistically significantly higher than the current method (0.855 and 0.707, respectively, p=0.031). This new method has the potential to improve early detection of glaucomatous structural damages.

  15. A physical model eye with 3D resolution test targets for optical coherence tomography

    Science.gov (United States)

    Hu, Zhixiong; Liu, Wenli; Hong, Baoyu; Hao, Bingtao; Wang, Lele; Li, Jiao

    2014-09-01

    Optical coherence tomography (OCT) has been widely employed as non-invasive 3D imaging diagnostic instrument, particularly in the field of ophthalmology. Although OCT has been approved for use in clinic in USA, Europe and Asia, international standardization of this technology is still in progress. Validation of OCT imaging capabilities is considered extremely important to ensure its effective use in clinical diagnoses. Phantom with appropriate test targets can assist evaluate and calibrate imaging performance of OCT at both installation and throughout lifetime of the instrument. In this paper, we design and fabricate a physical model eye with 3D resolution test targets to characterize OCT imaging performance. The model eye was fabricated with transparent resin to simulate realistic ophthalmic testing environment, and most key optical elements including cornea, lens and vitreous body were realized. The test targets which mimic USAF 1951 test chart were fabricated on the fundus of the model eye by 3D printing technology. Differing from traditional two dimensional USAF 1951 test chart, a group of patterns which have different thickness in depth were fabricated. By measuring the 3D test targets, axial resolution as well as lateral resolution of an OCT system can be evaluated at the same time with this model eye. To investigate this specialized model eye, it was measured by a scientific spectral domain OCT instrument and a clinical OCT system respectively. The results demonstrate that the model eye with 3D resolution test targets have the potential of qualitatively and quantitatively validating the performance of OCT systems.

  16. Investigation of inclined dual-fiber optical tweezers for 3D manipulation and force sensing.

    Science.gov (United States)

    Liu, Yuxiang; Yu, Miao

    2009-08-03

    Optical tweezers provide a versatile tool in biological and physical researches. Optical tweezers based on optical fibers are more flexible and ready to be integrated when compared with those based on microscope objectives. In this paper, the three-dimensional (3D) trapping ability of an inclined dual-fiber optical tweezers is demonstrated. The trapping efficiency with respect to displacement is experimentally calibrated along two dimensions. The system is studied numerically using a modified ray-optics model. The spring constants obtained in the experiment are predicted by simulations. It is found both experimentally and numerically that there is a critical value for the fiber inclination angle to retain the 3D trapping ability. The inclined dual-fiber optical tweezers are demonstrated to be more robust to z-axis misalignment than the counter-propagating fiber optical tweezers, which is a special case of th former when the fiber inclination angle is 90 masculine. This inclined dual-fiber optical tweezers can serve as both a manipulator and a force sensor in integrated systems, such as microfluidic systems and lab-on-a-chip systems.

  17. Single-cycle nonlinear optics

    Energy Technology Data Exchange (ETDEWEB)

    Max-Planck-Institut fur Quantenoptik; Goulielmakis, E.; Schultze, M.; Hofstetter, M.; Yakovlev, V. S.; Gagnon, J.; Uiberacker, M.; Aquila, A. L.; gullikson, E. M.; attwood, D. T.; Kienberger, R.; Krausz, F.; Kleineberg, U.

    2008-11-05

    Nonlinear optics plays a central role in the advancement of optical science and laser-based technologies. We report on the confinement of the nonlinear interaction of light with matter to a single wave cycle and demonstrate its utility for time-resolved and strong-field science. The electric field of 3.3-femtosecond, 0.72-micron laser pulses with a controlled and measured waveform ionizes atoms near the crests of the central wave cycle, with ionization being virtually switched off outside this interval. Isolated sub-100-attosecond pulses of extreme ultraviolet light (photon energy {approx} 80 electron volts), containing {approx} 0.5 nanojoule of energy, emerge from the interaction with a conversion efficiency of {approx} 10{sup -6}. These tools enable the study of the precision control of electron motion with light fields and electron-electron interactions with a resolution approaching the atomic unit of time ({approx} 24 attoseconds).

  18. Quantum Computation with Nonlinear Optics

    Science.gov (United States)

    Liu, Yang; Zhang, Wen-Hong; Zhang, Cun-Lin; Long, Gui-Lu

    2008-01-01

    We propose a scheme of quantum computation with nonlinear quantum optics. Polarization states of photons are used for qubits. Photons with different frequencies represent different qubits. Single qubit rotation operation is implemented through optical elements like the Faraday polarization rotator. Photons are separated into different optical paths, or merged into a single optical path using dichromatic mirrors. The controlled-NOT gate between two qubits is implemented by the proper combination of parametric up and down conversions. This scheme has the following features: (1) No auxiliary qubits are required in the controlled-NOT gate operation; (2) No measurement is required in the course of the computation; (3) It is resource efficient and conceptually simple.

  19. Quantum Computation with Nonlinear Optics

    Institute of Scientific and Technical Information of China (English)

    LU Ke; LIU Yang; LIN Zhen-Quan; ZHANG Wen-Hong; SUN Yun-Fei; ZHANG Cun-Lin; LONG Gui-Lu

    2008-01-01

    We propose a scheme of quantum computation with nonlinear quantum optics. Polarization states of photons are used for qubits. Photons with different frequencies represent different qubits. Single qubit rotation operation is implemented through optical elements like the Faraday polarization rotator. Photons are separated into different optical paths, or merged into a single optical path using dichromatic mirrors. The controlled-NOT gate between two qubits is implemented by the proper combination of parametric up and down conversions. This scheme has the following features: (1) No auxiliary qubits are required in the controlled-NOT gate operation; (2) No measurement is required in the courseof the computation; (3) It is resource efficient and conceptually simple.

  20. A 3D integral imaging optical see-through head-mounted display.

    Science.gov (United States)

    Hua, Hong; Javidi, Bahram

    2014-06-02

    An optical see-through head-mounted display (OST-HMD), which enables optical superposition of digital information onto the direct view of the physical world and maintains see-through vision to the real world, is a vital component in an augmented reality (AR) system. A key limitation of the state-of-the-art OST-HMD technology is the well-known accommodation-convergence mismatch problem caused by the fact that the image source in most of the existing AR displays is a 2D flat surface located at a fixed distance from the eye. In this paper, we present an innovative approach to OST-HMD designs by combining the recent advancement of freeform optical technology and microscopic integral imaging (micro-InI) method. A micro-InI unit creates a 3D image source for HMD viewing optics, instead of a typical 2D display surface, by reconstructing a miniature 3D scene from a large number of perspective images of the scene. By taking advantage of the emerging freeform optical technology, our approach will result in compact, lightweight, goggle-style AR display that is potentially less vulnerable to the accommodation-convergence discrepancy problem and visual fatigue. A proof-of-concept prototype system is demonstrated, which offers a goggle-like compact form factor, non-obstructive see-through field of view, and true 3D virtual display.

  1. Virtual touch 3D interactive system for autostereoscopic display with embedded optical sensor

    Science.gov (United States)

    Huang, Yi-Pai; Wang, Guo-Zhen; Ma, Ming-Ching; Tung, Shang-Yu; Huang, Shu-Yi; Tseng, Hung-Wei; Kuo, Chung-Hong; Li, Chun-Huai

    2011-06-01

    The traidational 3D interactive sysetm which uses CCD camera to capture image is difficult to operate on near range for mobile applications.Therefore, 3D interactive display with embedded optical sensor was proposed. Based on optical sensor based system, we proposed four different methods to support differenct functions. T mark algorithm can obtain 5- axis information (x, y, z,θ, and φ)of LED no matter where LED was vertical or inclined to panel and whatever it rotated. Sequential mark algorithm and color filter based algorithm can support mulit-user. Finally, bare finger touch system with sequential illuminator can achieve to interact with auto-stereoscopic images by bare finger. Furthermore, the proposed methods were verified on a 4-inch panel with embedded optical sensors.

  2. Performance of an improved first generation optical CT scanner for 3D dosimetry.

    Science.gov (United States)

    Qian, Xin; Adamovics, John; Wuu, Cheng-Shie

    2013-12-21

    Performance analysis of a modified 3D dosimetry optical scanner based on the first generation optical CT scanner OCTOPUS is presented. The system consists of PRESAGE dosimeters, the modified 3D scanner, and a new developed in-house user control panel written in Labview program which provides more flexibility to optimize mechanical control and data acquisition technique. The total scanning time has been significantly reduced from initial 8 h to ∼2 h by using the modified scanner. The functional performance of the modified scanner has been evaluated in terms of the mechanical integrity uncertainty of the data acquisition process. Optical density distribution comparison between the modified scanner, OCTOPUS and the treatment plan system has been studied. It has been demonstrated that the agreement between the modified scanner and treatment plans is comparable with that between the OCTOPUS and treatment plans.

  3. Organosilicon Polymeric Nonlinear Optical Materials for Optical Switching and Modulation

    Science.gov (United States)

    1994-02-28

    Organosilicon Polymeric Nonlinear Optical Materials for Optical C: F49620-93-C-0039 Switching and Modulation 6. AUTHOR(S) Mr. Sandip K. Sengupta, Dr...D FINAL REPORT for Organosilicon Polymeric Nonlinear Optical Materials for Optical Switching and Modulation Prepared for: USAF, AFMC (AFOSR) Air Force...34Organosilicon Polymeric Nonlinear Optical Materials for Optical Switching and Modulation," contract number F49620-93-C-0039. The work has been performed by Dr

  4. Generation of nearly 3D-unpolarized evanescent optical near fields using total internal reflection.

    Science.gov (United States)

    Hassinen, Timo; Popov, Sergei; Friberg, Ari T; Setälä, Tero

    2016-07-01

    We analyze the time-domain partial polarization of optical fields composed of two evanescent waves created in total internal reflection by random electromagnetic beams with orthogonal planes of incidence. We show that such a two-beam configuration enables to generate nearly unpolarized, genuine three-component (3D) near fields. This result complements earlier studies on spectral polarization, which state that at least three symmetrically propagating beams are required to produce a 3D-unpolarized near field. The degree of polarization of the near field can be controlled by adjusting the polarization states and mutual correlation of the incident beams.

  5. Traceability of Height Measurements on Green Sand Molds using Optical 3D Scanning

    DEFF Research Database (Denmark)

    Mohaghegh, Kamran; Yazdanbakhsh, S.A.; Tiedje, N. S.

    2016-01-01

    (CMM) which is traceable to the meter unit. Optical scanners are increasingly used for dimensional metrology without the risk of damaging the surface, but lack of international standards makes it difficult to establish traceability of their measurements and compare them to tactile instruments....... This paper presents a metrological approach for height measurement on green sand molds using an optical 3D scanner with fringe projection. A new sand sample was developed with a hard binder to withstand the contact force of a touch probe, while keeping optical cooperativeness similar to green sand...

  6. Realization of optical multimode TSV waveguides for Si-Interposer in 3D-chip-stacks

    Science.gov (United States)

    Killge, S.; Charania, S.; Richter, K.; Neumann, N.; Al-Husseini, Z.; Plettemeier, D.; Bartha, J. W.

    2017-05-01

    Optical connectivity has the potential to outperform copper-based TSVs in terms of bandwidth at the cost of more complexity due to the required electro-optical and opto-electrical conversion. The continuously increasing demand for higher bandwidth pushes the breakeven point for a profitable operation to shorter distances. To integrate an optical communication network in a 3D-chip-stack optical through-silicon vertical VIAs (TSV) are required. While the necessary effort for the electrical/optical and vice versa conversion makes it hard to envision an on-chip optical interconnect, a chip-to-chip optical link appears practicable. In general, the interposer offers the potential advantage to realize electro-optical transceivers on affordable expense by specific, but not necessarily CMOS technology. We investigated the realization and characterization of optical interconnects as a polymer based waveguide in high aspect ratio (HAR) TSVs proved on waferlevel. To guide the optical field inside a TSV as optical-waveguide or fiber, its core has to have a higher refractive index than the surrounding material. Comparing different material / technology options it turned out that thermal grown silicon dioxide (SiO2) is a perfect candidate for the cladding (nSiO2 = 1.4525 at 850 nm). In combination with SiO2 as the adjacent polymer layer, the negative resist SU-8 is very well suited as waveguide material (nSU-8 = 1.56) for the core. Here, we present the fabrication of an optical polymer based multimode waveguide in TSVs proved on waferlevel using SU-8 as core and SiO2 as cladding. The process resulted in a defect-free filling of waveguide TSVs with SU-8 core and SiO2 cladding up to aspect ratio (AR) 20:1 and losses less than 3 dB.

  7. Linear and nonlinear MHD mode coupling of the fast magnetoacoustic wave about a 3D magnetic null point

    Science.gov (United States)

    Thurgood, J. O.; McLaughlin, J. A.

    2012-09-01

    Context. Coronal magnetic null points have been implicated as possible locations for localised heating events in 2D models. We investigate this possibility about fully 3D null points. Aims: We investigate the nature of the fast magnetoacoustic wave about a fully 3D magnetic null point, with a specific interest in its propagation, and we look for evidence of MHD mode coupling and/or conversion to the Alfvén mode. Methods: A special fieldline and flux-based coordinate system was constructed to permit the introduction of a pure fast magnetoacoustic wave in the vicinity of proper and improper 3D null points. We considered the ideal, β = 0, MHD equations, which are solved using the LARE3D numerical code. The constituent modes of the resulting wave were isolated and identified using the special coordinate system. Numerical results were supported by analytical work derived from perturbation theory and a linear implementation of the WKB method. Results: An initially pure fast wave is found to be permanently decoupled from the Alfvén mode both linearly and nonlinearly for both proper and improper 3D null points. The pure fast mode also generates and sustains a nonlinear disturbance aligned along the equilibrium magnetic field. The resulting pure fast magnetoacoustic pulse has transient behaviour, which is found to be governed by the (equilibrium) Alfvén-speed profile, and a refraction effect focuses all the wave energy towards the null point. Conclusions: Thus, the main results from previous 2D work do indeed carry over to the fully 3D magnetic null points and so we conclude that 3D null points are locations for preferential heating in the corona by 3D fast magnetoacoustic waves.

  8. 3D printing of tissue-simulating phantoms for calibration of biomedical optical devices

    Science.gov (United States)

    Zhao, Zuhua; Zhou, Ximing; Shen, Shuwei; Liu, Guangli; Yuan, Li; Meng, Yuquan; Lv, Xiang; Shao, Pengfei; Dong, Erbao; Xu, Ronald X.

    2016-10-01

    Clinical utility of many biomedical optical devices is limited by the lack of effective and traceable calibration methods. Optical phantoms that simulate biological tissues used for optical device calibration have been explored. However, these phantoms can hardly simulate both structural and optical properties of multi-layered biological tissue. To address this limitation, we develop a 3D printing production line that integrates spin coating, light-cured 3D printing and Fused Deposition Modeling (FDM) for freeform fabrication of optical phantoms with mechanical and optical heterogeneities. With the gel wax Polydimethylsiloxane (PDMS), and colorless light-curable ink as matrix materials, titanium dioxide (TiO2) powder as the scattering ingredient, graphite powder and black carbon as the absorption ingredient, a multilayer phantom with high-precision is fabricated. The absorption and scattering coefficients of each layer are measured by a double integrating sphere system. The results demonstrate that the system has the potential to fabricate reliable tissue-simulating phantoms to calibrate optical imaging devices.

  9. Mapping 3D fiber orientation in tissue using dual-angle optical polarization tractography.

    Science.gov (United States)

    Wang, Y; Ravanfar, M; Zhang, K; Duan, D; Yao, G

    2016-10-01

    Optical polarization tractography (OPT) has recently been applied to map fiber organization in the heart, skeletal muscle, and arterial vessel wall with high resolution. The fiber orientation measured in OPT represents the 2D projected fiber angle in a plane that is perpendicular to the incident light. We report here a dual-angle extension of the OPT technology to measure the actual 3D fiber orientation in tissue. This method was first verified by imaging the murine extensor digitorum muscle placed at various known orientations in space. The accuracy of the method was further studied by analyzing the 3D fiber orientation of the mouse tibialis anterior muscle. Finally we showed that dual-angle OPT successfully revealed the unique 3D "arcade" fiber structure in the bovine articular cartilage.

  10. Toward a scalable flexible-order model for 3D nonlinear water waves

    DEFF Research Database (Denmark)

    Engsig-Karup, Allan Peter; Ducrozet, Guillaume; Bingham, Harry B.

    strategy on a time-invariant mesh. The 3D numerical model is based on a finite difference method as in the original works \\cite{LiFleming1997,BinghamZhang2007}. Full details and other aspects of an improved 3D solution can be found in \\cite{EBL08}. The new and improved approach for three...

  11. Obstacle detection and terrain characterization using optical flow without 3-D reconstruction

    Science.gov (United States)

    Young, Gin-Shu; Hong, Tsai Hong; Herman, Martin; Yang, Jackson C. S.

    1992-11-01

    For many applications in computer vision, it is important to recover range, 3-D motion, and/or scene geometry from a sequence of images. However, there are many robot behaviors which can be achieved by extracting relevant 2-D information from the imagery and using this information directly, without recovery of such information. In this paper, we focus on two behaviors, obstacle avoidance and terrain navigation. A novel method of these two behaviors has been developed without 3-D reconstruction. This approach is often called purposive active vision. A linear relationship, plotted as a line and called a reference flow line, has been found. The difference between a plotted line and the reference flow line can be used to detect discrete obstacles above or below the reference terrain. For terrain characterization, slopes of surface regions can be calculated directly from optical flow. Some error analysis is also done. The main features of this approach are that (1) discrete obstacles are detected directly from 2-D optical flow, no 3-D reconstruction is performed; (2) terrain slopes are also calculated from 2- D optical flow; (3) knowledge about the terrain model, camera-to-ground coordinate transformation, or vehicle (or camera) motion is not required; (4) the error sources involved are reduced to a minimum, since the only information required is a component of optical flow. An initial experiment using noisy synthetic data is also included to demonstrate the applicability and robustness of the method.

  12. Nonlinear optical interactions in silicon waveguides

    Science.gov (United States)

    Kuyken, B.; Leo, F.; Clemmen, S.; Dave, U.; Van Laer, R.; Ideguchi, T.; Zhao, H.; Liu, X.; Safioui, J.; Coen, S.; Gorza, S. P.; Selvaraja, S. K.; Massar, S.; Osgood, R. M.; Verheyen, P.; Van Campenhout, J.; Baets, R.; Green, W. M. J.; Roelkens, G.

    2017-03-01

    The strong nonlinear response of silicon photonic nanowire waveguides allows for the integration of nonlinear optical functions on a chip. However, the detrimental nonlinear optical absorption in silicon at telecom wavelengths limits the efficiency of many such experiments. In this review, several approaches are proposed and demonstrated to overcome this fundamental issue. By using the proposed methods, we demonstrate amongst others supercontinuum generation, frequency comb generation, a parametric optical amplifier, and a parametric optical oscillator.

  13. Automatic 3-D Optical Detection on Orientation of Randomly Oriented Industrial Parts for Rapid Robotic Manipulation

    Directory of Open Access Journals (Sweden)

    Liang-Chia Chen

    2012-12-01

    Full Text Available This paper proposes a novel method employing a developed 3-D optical imaging and processing algorithm for accurate classification of an object’s surface characteristics in robot pick and place manipulation. In the method, 3-D geometry of industrial parts can be rapidly acquired by the developed one-shot imaging optical probe based on Fourier Transform Profilometry (FTP by using digital-fringe projection at a camera’s maximum sensing speed. Following this, the acquired range image can be effectively segmented into three surface types by classifying point clouds based on the statistical distribution of the normal surface vector of each detected 3-D point, and then the scene ground is reconstructed by applying least squares fitting and classification algorithms. Also, a recursive search process incorporating the region-growing algorithm for registering homogeneous surface regions has been developed. When the detected parts are randomly overlapped on a workbench, a group of defined 3-D surface features, such as surface areas, statistical values of the surface normal distribution and geometric distances of defined features, can be uniquely recognized for detection of the part’s orientation. Experimental testing was performed to validate the feasibility of the developed method for real robotic manipulation.

  14. BER Analysis Using Beat Probability Method of 3D Optical CDMA Networks with Double Balanced Detection

    Directory of Open Access Journals (Sweden)

    Chih-Ta Yen

    2015-01-01

    Full Text Available This study proposes novel three-dimensional (3D matrices of wavelength/time/spatial code for code-division multiple-access (OCDMA networks, with a double balanced detection mechanism. We construct 3D carrier-hopping prime/modified prime (CHP/MP codes by extending a two-dimensional (2D CHP code integrated with a one-dimensional (1D MP code. The corresponding coder/decoder pairs were based on fiber Bragg gratings (FBGs and tunable optical delay lines integrated with splitters/combiners. System performance was enhanced by the low cross correlation properties of the 3D code designed to avoid the beat noise phenomenon. The CHP/MP code cardinality increased significantly compared to the CHP code under the same bit error rate (BER. The results indicate that the 3D code method can enhance system performance because both the beating terms and multiple-access interference (MAI were reduced by the double balanced detection mechanism. Additionally, the optical component can also be relaxed for high transmission scenery.

  15. Graphene - a rather ordinary nonlinear optical material

    CERN Document Server

    khurgin, Jacob B

    2014-01-01

    An analytical expression for the nonlinear refractive index of graphene has been derived and used to obtain the performance metrics of third order nonlinear devices using graphene as a nonlinear medium. None of the metrics is found to be superior to the existing nonlinear optical materials.

  16. Quantification of smoothing requirement for 3D optic flow calculation of volumetric images

    DEFF Research Database (Denmark)

    Bab-Hadiashar, Alireza; Tennakoon, Ruwan B.; de Bruijne, Marleen

    2013-01-01

    that a (surprisingly) small amount of local smoothing is required to satisfy both the necessary and sufficient conditions for accurate optic flow estimation. This notion is called 'just enough' smoothing, and its proper implementation has a profound effect on the preservation of local information in processing 3D...... dynamic scans. To demonstrate the effect of 'just enough' smoothing, a robust 3D optic flow method with quantized local smoothing is presented, and the effect of local smoothing on the accuracy of motion estimation in dynamic lung CT images is examined using both synthetic and real image sequences......Complexities of dynamic volumetric imaging challenge the available computer vision techniques on a number of different fronts. This paper examines the relationship between the estimation accuracy and required amount of smoothness for a general solution from a robust statistics perspective. We show...

  17. Design and verification of diffractive optical elements for speckle generation of 3-D range sensors

    Science.gov (United States)

    Du, Pei-Qin; Shih, Hsi-Fu; Chen, Jenq-Shyong; Wang, Yi-Shiang

    2016-09-01

    The optical projection using speckles is one of the structured light methods that have been applied to three-dimensional (3-D) range sensors. This paper investigates the design and fabrication of diffractive optical elements (DOEs) for generating the light field with uniformly distributed speckles. Based on the principles of computer generated holograms, the iterative Fourier transform algorithm was adopted for the DOE design. It was used to calculate the phase map for diffracting the incident laser beam into a goal pattern with distributed speckles. Four patterns were designed in the study. Their phase maps were first examined by a spatial light modulator and then fabricated on glass substrates by microfabrication processes. Finally, the diffraction characteristics of the fabricated devices were verified. The experimental results show that the proposed methods are applicable to the DOE design of 3-D range sensors. Furthermore, any expected diffraction area and speckle density could be possibly achieved according to the relations presented in the paper.

  18. Optical properties of 3d-ions in crystals spectroscopy and crystal field analysis

    CERN Document Server

    Brik, Mikhail

    2013-01-01

    "Optical Properties of 3d-Ions in Crystals: Spectroscopy and Crystal Field Analysis" discusses spectral, vibronic and magnetic properties of 3d-ions in a wide range of crystals, used as active media for solid state lasers and potential candidates for this role. Crystal field calculations (including first-principles calculations of energy levels and absorption spectra) and their comparison with experimental spectra, the Jahn-Teller effect, analysis of vibronic spectra, materials science applications are systematically presented. The book is intended for researchers and graduate students in crystal spectroscopy, materials science and optical applications. Dr. N.M. Avram is an Emeritus Professor at the Physics Department, West University of Timisoara, Romania; Dr. M.G. Brik is a Professor at the Institute of Physics, University of Tartu, Estonia.

  19. Design and verification of diffractive optical elements for speckle generation of 3-D range sensors

    Science.gov (United States)

    Du, Pei-Qin; Shih, Hsi-Fu; Chen, Jenq-Shyong; Wang, Yi-Shiang

    2016-12-01

    The optical projection using speckles is one of the structured light methods that have been applied to three-dimensional (3-D) range sensors. This paper investigates the design and fabrication of diffractive optical elements (DOEs) for generating the light field with uniformly distributed speckles. Based on the principles of computer generated holograms, the iterative Fourier transform algorithm was adopted for the DOE design. It was used to calculate the phase map for diffracting the incident laser beam into a goal pattern with distributed speckles. Four patterns were designed in the study. Their phase maps were first examined by a spatial light modulator and then fabricated on glass substrates by microfabrication processes. Finally, the diffraction characteristics of the fabricated devices were verified. The experimental results show that the proposed methods are applicable to the DOE design of 3-D range sensors. Furthermore, any expected diffraction area and speckle density could be possibly achieved according to the relations presented in the paper.

  20. Nonlinear optical crystals a complete survey

    CERN Document Server

    Nikogosyan, David N

    2005-01-01

    Nonlinear optical crystals are widely used in modern optical science and technology for frequency conversion of laser light, i.e. to generate laser radiation at any specific wavelength in visible, UV or IR spectral regions. This unrivalled reference book contains the most complete and up-to-date information on properties of nonlinear optical crystals. It includes: * Database of 63 common and novel nonlinear optical crystals * Periodically-poled and self-frequency-doubling materials * Full description of linear and nonlinear optical properties * Significant amount of crystallophysical, thermophysical, spectroscopic, electro-optic and magneto-optic information * 7 mini-reviews on novel applications, such as deep-UV light generation, terahertz-wave generation, ultrashort laser pulse compression, photonic band-gap crystals, x3 nonlinearity, etc. * More than 1500 different references with full titles It is a vital source of information for scientists and engineers dealing with modern applications of nonlinear opti...

  1. Quantum nonlinear optics without photons

    Science.gov (United States)

    Stassi, Roberto; Macrı, Vincenzo; Kockum, Anton Frisk; Di Stefano, Omar; Miranowicz, Adam; Savasta, Salvatore; Nori, Franco

    2017-08-01

    Spontaneous parametric down-conversion is a well-known process in quantum nonlinear optics in which a photon incident on a nonlinear crystal spontaneously splits into two photons. Here we propose an analogous physical process where one excited atom directly transfers its excitation to a pair of spatially separated atoms with probability approaching 1. The interaction is mediated by the exchange of virtual rather than real photons. This nonlinear atomic process is coherent and reversible, so the pair of excited atoms can transfer the excitation back to the first one: the atomic analog of sum-frequency generation of light. The parameters used to investigate this process correspond to experimentally demonstrated values in ultrastrong circuit quantum electrodynamics. This approach can be extended to realize other nonlinear interatomic processes, such as four-atom mixing, and is an attractive architecture for the realization of quantum devices on a chip. We show that four-qubit mixing can efficiently implement quantum repetition codes and, thus, can be used for error-correction codes.

  2. 3D printed sensing patches with embedded polymer optical fibre Bragg gratings

    Science.gov (United States)

    Zubel, Michal G.; Sugden, Kate; Saez-Rodriguez, D.; Nielsen, K.; Bang, O.

    2016-05-01

    The first demonstration of a polymer optical fibre Bragg grating (POFBG) embedded in a 3-D printed structure is reported. Its cyclic strain performance and temperature characteristics are examined and discussed. The sensing patch has a repeatable strain sensitivity of 0.38 pm/μepsilon. Its temperature behaviour is unstable, with temperature sensitivity values varying between 30-40 pm/°C.

  3. Rapid fabrication of complex 3D extracellular microenvironments by dynamic optical projection stereolithography.

    Science.gov (United States)

    Zhang, A Ping; Qu, Xin; Soman, Pranav; Hribar, Kolin C; Lee, Jin W; Chen, Shaochen; He, Sailing

    2012-08-16

    The topographic features of the extracelluar matrix (ECM) lay the foundation for cellular behavior. A novel biofabrication method using a digital-mirror device (DMD), called dynamic optical projection stereolithography (DOPsL) is demonstrated. This robust and versatile platform can generate complex biomimetic scaffolds within seconds. Such 3D scaffolds have promising potentials for studying cell interactions with microenvironments in vitro and in vivo.

  4. Application of adaptive non-linear 2D and 3D postprocessing filters for reduced dose abdominal CT.

    Science.gov (United States)

    Borgen, Lars; Kalra, Mannudeep K; Laerum, Frode; Hachette, Isabelle W; Fredriksson, Carina H; Sandborg, Michael; Smedby, Orjan

    2012-04-01

    Abdominal computed tomography (CT) is a frequently performed imaging procedure, resulting in considerable radiation doses to the patient population. Postprocessing filters are one of several dose reduction measures that might help to reduce radiation doses without loss of image quality. To assess and compare the effect of two- and three-dimensional (2D, 3D) non-linear adaptive filters on reduced dose abdominal CT images. Two baseline abdominal CT image series with a volume computer tomography dose index (CTDI (vol)) of 12 mGy and 6 mGy were acquired for 12 patients. Reduced dose images were postprocessed with 2D and 3D filters. Six radiologists performed blinded randomized, side-by-side image quality assessments. Objective noise was measured. Data were analyzed using visual grading regression and mixed linear models. All image quality criteria were rated as superior for 3D filtered images compared to reduced dose baseline and 2D filtered images (P 0.05). There were no significant variations of objective noise between standard dose and 2D or 3D filtered images. The quality of 3D filtered reduced dose abdominal CT images is superior compared to reduced dose unfiltered and 2D filtered images. For patients with BMI < 30 kg/m(2), 3D filtered images are comparable to standard dose images.

  5. Target Tracking in 3-D Using Estimation Based Nonlinear Control Laws for UAVs

    National Research Council Canada - National Science Library

    Mousumi Ahmed; Kamesh Subbarao

    2016-01-01

    ...) to track a moving target in 3-D space. A ground-based sensor or an onboard seeker antenna provides range, azimuth angle, and elevation angle measurements to a chaser UAV that implements an extended Kalman filter (EKF...

  6. Active optical system for advanced 3D surface structuring by laser remelting

    Science.gov (United States)

    Pütsch, O.; Temmler, A.; Stollenwerk, J.; Willenborg, E.; Loosen, P.

    2015-03-01

    Structuring by laser remelting enables completely new possibilities for designing surfaces since material is redistributed but not wasted. In addition to technological advantages, cost and time benefits yield from shortened process times, the avoidance of harmful chemicals and the elimination of subsequent finishing steps such as cleaning and polishing. The functional principle requires a completely new optical machine technology that maintains the spatial and temporal superposition and manipulation of three different laser beams emitted from two laser sources of different wavelength. The optical system has already been developed and demonstrated for the processing of flat samples of hot and cold working steel. However, since particularly the structuring of 3D-injection molds represents an application example of high innovation potential, the optical system has to take into account the elliptical beam geometry that occurs when the laser beams irradiate a curved surface. To take full advantage of structuring by remelting for the processing of 3D surfaces, additional optical functionality, called EPS (elliptical pre-shaping) has to be integrated into the existing set-up. The development of the beam shaping devices not only requires the analysis of the mechanisms of the beam projection but also a suitable optical design. Both aspects are discussed in this paper.

  7. Application of adaptive non-linear 2D and 3D postprocessing filters for reduced dose abdominal CT

    Energy Technology Data Exchange (ETDEWEB)

    Borgen, Lars (Dept. of Radiology, Drammen Hospital, Drammen and Buskerud Univ. College, Drammen (Norway)), Email: lars.borgen@vestreviken.no; Kalra, Mannudeep K. (Massachusetts General Hospital Imaging, Harvard Medical School, Massachusetts General Hospital, Boston (United States)); Laerum, Frode (Dept. of Radiology, Akershus Univ. Hospital, Loerenskog (Norway)); Hachette, Isabelle W.; Fredriksson, Carina H. (ContextVision AB, Linkoeping (Sweden)); Sandborg, Michael (Dept. of Medical Physics, IMH, Faculty of Health Sciences, Linkoeping Univ., County Council of Oestergoetland, Linkoeping (Sweden); Center for Medical Image Science and Visualization, Linkoeping (Sweden)); Smedby, Oerjan (Center for Medical Image Science and Visualization, Linkoeping (Sweden); Dept. of Radiology, Linkoeping Univ., Linkoeping (Sweden))

    2012-04-15

    Background: Abdominal computed tomography (CT) is a frequently performed imaging procedure, resulting in considerable radiation doses to the patient population. Postprocessing filters are one of several dose reduction measures that might help to reduce radiation doses without loss of image quality. Purpose: To assess and compare the effect of two- and three-dimensional (2D, 3D) non-linear adaptive filters on reduced dose abdominal CT images. Material and Methods: Two baseline abdominal CT image series with a volume computer tomography dose index (CTDI{sub vol}) of 12 mGy and 6 mGy were acquired for 12 patients. Reduced dose images were postprocessed with 2D and 3D filters. Six radiologists performed blinded randomized, side-by-side image quality assessments. Objective noise was measured. Data were analyzed using visual grading regression and mixed linear models. Results: All image quality criteria were rated as superior for 3D filtered images compared to reduced dose baseline and 2D filtered images (P < 0.01). Standard dose images had better image quality than reduced dose 3D filtered images (P < 0.01), but similar image noise. For patients with body mass index (BMI) < 30 kg/m2 however, 3D filtered images were rated significantly better than normal dose images for two image criteria (P < 0.05), while no significant difference was found for the remaining three image criteria (P > 0.05). There were no significant variations of objective noise between standard dose and 2D or 3D filtered images. Conclusion: The quality of 3D filtered reduced dose abdominal CT images is superior compared to reduced dose unfiltered and 2D filtered images. For patients with BMI < 30 kg/m2, 3D filtered images are comparable to standard dose images

  8. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images.

    Science.gov (United States)

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N; Zangwill, Linda M

    2014-03-18

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the "non-progressing" and "progressing" glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection.

  9. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images

    Science.gov (United States)

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N.; Zangwill, Linda M.

    2014-03-01

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the "non-progressing" and "progressing" glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection.

  10. Block matching 3D random noise filtering for absorption optical projection tomography

    Energy Technology Data Exchange (ETDEWEB)

    Fumene Feruglio, P; Vinegoni, C; Weissleder, R [Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, MA 02114 (United States); Gros, J [Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston MA 02115 (United States); Sbarbati, A, E-mail: cvinegoni@mgh.harvard.ed [Department of Morphological and Biomedical Sciences, University of Verona, Strada Le Grazie 8, 37134 Verona (Italy)

    2010-09-21

    Absorption and emission optical projection tomography (OPT), alternatively referred to as optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT), are recently developed three-dimensional imaging techniques with value for developmental biology and ex vivo gene expression studies. The techniques' principles are similar to the ones used for x-ray computed tomography and are based on the approximation of negligible light scattering in optically cleared samples. The optical clearing is achieved by a chemical procedure which aims at substituting the cellular fluids within the sample with a cell membranes' index matching solution. Once cleared the sample presents very low scattering and is then illuminated with a light collimated beam whose intensity is captured in transillumination mode by a CCD camera. Different projection images of the sample are subsequently obtained over a 360{sup 0} full rotation, and a standard backprojection algorithm can be used in a similar fashion as for x-ray tomography in order to obtain absorption maps. Because not all biological samples present significant absorption contrast, it is not always possible to obtain projections with a good signal-to-noise ratio, a condition necessary to achieve high-quality tomographic reconstructions. Such is the case for example, for early stage's embryos. In this work we demonstrate how, through the use of a random noise removal algorithm, the image quality of the reconstructions can be considerably improved even when the noise is strongly present in the acquired projections. Specifically, we implemented a block matching 3D (BM3D) filter applying it separately on each acquired transillumination projection before performing a complete three-dimensional tomographical reconstruction. To test the efficiency of the adopted filtering scheme, a phantom and a real biological sample were processed. In both cases, the BM3D filter led to a signal-to-noise ratio

  11. The quantum theory of nonlinear optics

    CERN Document Server

    Drummond, Peter D

    2014-01-01

    Playing a prominent role in communications, quantum science and laser physics, quantum nonlinear optics is an increasingly important field. This book presents a self-contained treatment of field quantization and covers topics such as the canonical formalism for fields, phase-space representations and the encompassing problem of quantization of electrodynamics in linear and nonlinear media. Starting with a summary of classical nonlinear optics, it then explains in detail the calculation techniques for quantum nonlinear optical systems and their applications, quantum and classical noise sources in optical fibers and applications of nonlinear optics to quantum information science. Supplemented by end-of-chapter exercises and detailed examples of calculation techniques in different systems, this book is a valuable resource for graduate students and researchers in nonlinear optics, condensed matter physics, quantum information and atomic physics. A solid foundation in quantum mechanics and classical electrodynamic...

  12. Development of a nonlinear 3D solid finite element model for the calculation of bending moments of flexural members

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A numerical model is developed in this paper to calculate the bending moments of flexural members through integration in 3D solid finite element analyses according to the nonlinear constitutive model of concrete and the elastoplastic constitutive model of steel,utilizing the stress condition of the cross-section,considering the destruction characteristic of reinforced concrete members,and based on the plane cross-section assumption.The results of this model give good agreement with those of the classical me...

  13. Equilibrium equations for nonlinear buckling analysis of drill-strings in 3D curved well-bores

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    With the development of drilling technology, the oil/gas well has evolved from its early vertical straight form to the inclined, horizontal, plane curved, or even 3D curved well-bore. Understanding of the buck- ling behavior of a drill-string in a well-bore is crucial for the success of a drilling operation. Therefore, equilibrium equations for analyzing the buckling behavior of a drill-string in a 3D curved well-bore are required. Based on Love’s equilibrium equations for a curved and twisted rod in space, a set of equi- librium equations for the nonlinear buckling analysis of a drill-string in a 3D curved well-bore are de- rived by introducing a radial constraint of the well-bore. The proposed formulae can account for the well curvature and tortuosity. Thus, it can be used to analyze the buckling behaviors of a drill-string constrained in a well-bore and subjected to axial compression, torsion at its upper end, and gravity simultaneously. It is worth noting that the existing equations in the literature for a drill-string in a straight and plane curved well-bore with a constant curvature are a special case of the proposed model. Thus, the present model can provide a theoretical basis for the nonlinear buckling analysis of a drill-string constrained in a 3D curved well-bore.

  14. Equilibrium equations for nonlinear buckling analysis of drill-strings in 3D curved well-bores

    Institute of Scientific and Technical Information of China (English)

    TAN MeiLan; GAN LiFei

    2009-01-01

    With the development of drilling technology, the oil/gas well has evolved from its early vertical straight form to the inclined, horizontal, plane curved, or even 3D curved well-bore. Understanding of the buck-ling behavior of a drill-string in a well-bore is crucial for the success of a drilling operation. Therefore, equilibrium equations for analyzing the buckling behavior of a drill-string in a 3D curved well-bore are required. Based on Love's equilibrium equations for a curved and twisted rod in space, s set of equi-librium equations for the nonlinear buckling analysis of a drill-string in a 3D curved well-bore are de-rived by introducing a radial constraint of the well-bore. The proposed formulae can account for the well curvature and tortuosity. Thus, it can be used to analyze the buckling behaviors of a drill-string constrained in a well-bore and subjected to axial compression, torsion at its upper end, and gravity simultaneously. It is worth noting that the existing equations in the literature for a drill-string in a straight and plane curved well-bore with a constant curvature are a special case of the proposed model. Thus, the present model can provide s theoretical basis for the nonlinear buckling analysis of a drill-string constrained in a 3D curved well-bore.

  15. New 3D parallel GILD electromagnetic modeling and nonlinear inversion using global magnetic integral and local differential equation

    Energy Technology Data Exchange (ETDEWEB)

    Xie, G.; Li, J.; Majer, E.; Zuo, D.

    1998-07-01

    This paper describes a new 3D parallel GILD electromagnetic (EM) modeling and nonlinear inversion algorithm. The algorithm consists of: (a) a new magnetic integral equation instead of the electric integral equation to solve the electromagnetic forward modeling and inverse problem; (b) a collocation finite element method for solving the magnetic integral and a Galerkin finite element method for the magnetic differential equations; (c) a nonlinear regularizing optimization method to make the inversion stable and of high resolution; and (d) a new parallel 3D modeling and inversion using a global integral and local differential domain decomposition technique (GILD). The new 3D nonlinear electromagnetic inversion has been tested with synthetic data and field data. The authors obtained very good imaging for the synthetic data and reasonable subsurface EM imaging for the field data. The parallel algorithm has high parallel efficiency over 90% and can be a parallel solver for elliptic, parabolic, and hyperbolic modeling and inversion. The parallel GILD algorithm can be extended to develop a high resolution and large scale seismic and hydrology modeling and inversion in the massively parallel computer.

  16. A comprehensive evaluation of the PRESAGE/optical-CT 3D dosimetry system

    Energy Technology Data Exchange (ETDEWEB)

    Sakhalkar, H. S.; Adamovics, J.; Ibbott, G.; Oldham, M. [Department of Radiation Oncology Physics, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Chemistry and Biology, Rider University, Lawrenceville, New Jersey 08648 (United States); Department of Radiation Physics, M. D. Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiation Oncology Physics, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2009-01-15

    This work presents extensive investigations to evaluate the robustness (intradosimeter consistency and temporal stability of response), reproducibility, precision, and accuracy of a relatively new 3D dosimetry system comprising a leuco-dye doped plastic 3D dosimeter (PRESAGE) and a commercial optical-CT scanner (OCTOPUS 5x scanner from MGS Research, Inc). Four identical PRESAGE 3D dosimeters were created such that they were compatible with the Radiologic Physics Center (RPC) head-and-neck (H and N) IMRT credentialing phantom. Each dosimeter was irradiated with a rotationally symmetric arrangement of nine identical small fields (1x3 cm{sup 2}) impinging on the flat circular face of the dosimeter. A repetitious sequence of three dose levels (4, 2.88, and 1.28 Gy) was delivered. The rotationally symmetric treatment resulted in a dose distribution with high spatial variation in axial planes but only gradual variation with depth along the long axis of the dosimeter. The significance of this treatment was that it facilitated accurate film dosimetry in the axial plane, for independent verification. Also, it enabled rigorous evaluation of robustness, reproducibility and accuracy of response, at the three dose levels. The OCTOPUS 5x commercial scanner was used for dose readout from the dosimeters at daily time intervals. The use of improved optics and acquisition technique yielded substantially improved noise characteristics (reduced to {approx}2%) than has been achieved previously. Intradosimeter uniformity of radiochromic response was evaluated by calculating a 3D gamma comparison between each dosimeter and axially rotated copies of the same dosimeter. This convenient technique exploits the rotational symmetry of the distribution. All points in the gamma comparison passed a 2% difference, 1 mm distance-to-agreement criteria indicating excellent intradosimeter uniformity even at low dose levels. Postirradiation, the dosimeters were all found to exhibit a slight increase in

  17. Nonlinear Photonics and Novel Optical Phenomena

    CERN Document Server

    Morandotti, Roberto

    2012-01-01

    Nonlinear Photonics and Novel Optical Phenomena contains contributed chapters from leading experts in nonlinear optics and photonics, and provides a comprehensive survey of fundamental concepts as well as hot topics in current research on nonlinear optical waves and related novel phenomena. The book covers self-accelerating airy beams, integrated photonics based on high index doped-silica glass, linear and nonlinear spatial beam dynamics in photonic lattices and waveguide arrays, polariton solitons and localized structures in semiconductor microcavities, terahertz waves, and other novel phenomena in different nanophotonic and optical systems.

  18. 3D optical printing of piezoelectric nanoparticle-polymer composite materials.

    Science.gov (United States)

    Kim, Kanguk; Zhu, Wei; Qu, Xin; Aaronson, Chase; McCall, William R; Chen, Shaochen; Sirbuly, Donald J

    2014-10-28

    Here we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be optically printed into three-dimensional (3D) microstructures using digital projection printing. Piezoelectric polymers were fabricated by incorporating barium titanate (BaTiO3, BTO) nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate and exposing to digital optical masks that could be dynamically altered to generate user-defined 3D microstructures. To enhance the mechanical-to-electrical conversion efficiency of the composites, the BTO nanoparticles were chemically modified with acrylate surface groups, which formed direct covalent linkages with the polymer matrix under light exposure. The composites with a 10% mass loading of the chemically modified BTO nanoparticles showed piezoelectric coefficients (d(33)) of ∼ 40 pC/N, which were over 10 times larger than composites synthesized with unmodified BTO nanoparticles and over 2 times larger than composites containing unmodified BTO nanoparticles and carbon nanotubes to boost mechanical stress transfer efficiencies. These results not only provide a tool for fabricating 3D piezoelectric polymers but lay the groundwork for creating highly efficient piezoelectric polymer materials via nanointerfacial tuning.

  19. A new way to characterize autostereoscopic 3D displays using Fourier optics instrument

    Science.gov (United States)

    Boher, P.; Leroux, T.; Bignon, T.; Collomb-Patton, V.

    2009-02-01

    Auto-stereoscopic 3D displays offer presently the most attractive solution for entertainment and media consumption. Despite many studies devoted to this type of technology, efficient characterization methods are still missing. We present here an innovative optical method based on high angular resolution viewing angle measurements with Fourier optics instrument. This type of instrument allows measuring the full viewing angle aperture of the display very rapidly and accurately. The system used in the study presents a very high angular resolution below 0.04 degree which is mandatory for this type of characterization. We can predict from the luminance or color viewing angle measurements of the different views of the 3D display what will be seen by an observer at any position in front of the display. Quality criteria are derived both for 3D and standard properties at any observer position and Qualified Stereo Viewing Space (QSVS) is determined. The use of viewing angle measurements at different locations on the display surface during the observer computation gives more realistic estimation of QSVS and ensures its validity for the entire display surface. Optimum viewing position, viewing freedom, color shifts and standard parameters are also quantified. Simulation of the moire issues can be made leading to a better understanding of their origin.

  20. Accurate 3D maps from depth images and motion sensors via nonlinear Kalman filtering

    CERN Document Server

    Hervier, Thibault; Goulette, François

    2012-01-01

    This paper investigates the use of depth images as localisation sensors for 3D map building. The localisation information is derived from the 3D data thanks to the ICP (Iterative Closest Point) algorithm. The covariance of the ICP, and thus of the localization error, is analysed, and described by a Fisher Information Matrix. It is advocated this error can be much reduced if the data is fused with measurements from other motion sensors, or even with prior knowledge on the motion. The data fusion is performed by a recently introduced specific extended Kalman filter, the so-called Invariant EKF, and is directly based on the estimated covariance of the ICP. The resulting filter is very natural, and is proved to possess strong properties. Experiments with a Kinect sensor and a three-axis gyroscope prove clear improvement in the accuracy of the localization, and thus in the accuracy of the built 3D map.

  1. Fibre-optic nonlinear optical microscopy and endoscopy.

    Science.gov (United States)

    Fu, L; Gu, M

    2007-06-01

    Nonlinear optical microscopy has been an indispensable laboratory tool of high-resolution imaging in thick tissue and live animals. Rapid developments of fibre-optic components in terms of growing functionality and decreasing size provide enormous opportunities for innovations in nonlinear optical microscopy. Fibre-based nonlinear optical endoscopy is the sole instrumentation to permit the cellular imaging within hollow tissue tracts or solid organs that are inaccessible to a conventional optical microscope. This article reviews the current development of fibre-optic nonlinear optical microscopy and endoscopy, which includes crucial technologies for miniaturized nonlinear optical microscopy and their embodiments of endoscopic systems. A particular attention is given to several classes of photonic crystal fibres that have been applied to nonlinear optical microscopy due to their unique properties for ultrashort pulse delivery and signal collection. Furthermore, fibre-optic nonlinear optical imaging systems can be classified into portable microscopes suitable for imaging behaving animals, rigid endoscopes that allow for deep tissue imaging with minimally invasive manners, and flexible endoscopes enabling imaging of internal organs. Fibre-optic nonlinear optical endoscopy is coming of age and a paradigm shift leading to optical microscope tools for early cancer detection and minimally invasive surgery.

  2. Three-Axis Distributed Fiber Optic Strain Measurement in 3D Woven Composite Structures

    Science.gov (United States)

    Castellucci, Matt; Klute, Sandra; Lally, Evan M.; Froggatt, Mark E.; Lowry, David

    2013-01-01

    Recent advancements in composite materials technologies have broken further from traditional designs and require advanced instrumentation and analysis capabilities. Success or failure is highly dependent on design analysis and manufacturing processes. By monitoring smart structures throughout manufacturing and service life, residual and operational stresses can be assessed and structural integrity maintained. Composite smart structures can be manufactured by integrating fiber optic sensors into existing composite materials processes such as ply layup, filament winding and three-dimensional weaving. In this work optical fiber was integrated into 3D woven composite parts at a commercial woven products manufacturing facility. The fiber was then used to monitor the structures during a VARTM manufacturing process, and subsequent static and dynamic testing. Low cost telecommunications-grade optical fiber acts as the sensor using a high resolution commercial Optical Frequency Domain Reflectometer (OFDR) system providing distributed strain measurement at spatial resolutions as low as 2mm. Strain measurements using the optical fiber sensors are correlated to resistive strain gage measurements during static structural loading. Keywords: fiber optic, distributed strain sensing, Rayleigh scatter, optical frequency domain reflectometry

  3. Development of scanning laser sensor for underwater 3D imaging with the coaxial optics

    Science.gov (United States)

    Ochimizu, Hideaki; Imaki, Masaharu; Kameyama, Shumpei; Saito, Takashi; Ishibashi, Shoujirou; Yoshida, Hiroshi

    2014-06-01

    We have developed the scanning laser sensor for underwater 3-D imaging which has the wide scanning angle of 120º (Horizontal) x 30º (Vertical) with the compact size of 25 cm diameter and 60 cm long. Our system has a dome lens and a coaxial optics to realize both the wide scanning angle and the compactness. The system also has the feature in the sensitivity time control (STC) circuit, in which the receiving gain is increased according to the time of flight. The STC circuit contributes to detect a small signal by suppressing the unwanted signals backscattered by marine snows. We demonstrated the system performance in the pool, and confirmed the 3-D imaging with the distance of 20 m. Furthermore, the system was mounted on the autonomous underwater vehicle (AUV), and demonstrated the seafloor mapping at the depth of 100 m in the ocean.

  4. Encryption of digital hologram of 3-D object by virtual optics

    Science.gov (United States)

    Kim, Hyun; Kim, Do-Hyung; Lee, Yeon H.

    2004-10-01

    We present a simple technique to encrypt a digital hologram of a three-dimensional (3-D) object into a stationary white noise by use of virtual optics and then to decrypt it digitally. In this technique the digital hologram is encrypted by our attaching a computer-generated random phase key to it and then forcing them to Fresnel propagate to an arbitrary plane with an illuminating plane wave of a given wavelength. It is shown in experiments that the proposed system is robust to blind decryptions without knowing the correct propagation distance, wavelength, and phase key used in the encryption. Signal-to-noise ratio (SNR) and mean-square-error (MSE) of the reconstructed 3-D object are calculated for various decryption distances and wavelengths, and partial use of the correct phase key.

  5. Intrathoracic tumour motion estimation from CT imaging using the 3D optical flow method

    Science.gov (United States)

    Guerrero, Thomas; Zhang, Geoffrey; Huang, Tzung-Chi; Lin, Kang-Ping

    2004-09-01

    The purpose of this work was to develop and validate an automated method for intrathoracic tumour motion estimation from breath-hold computed tomography (BH CT) imaging using the three-dimensional optical flow method (3D OFM). A modified 3D OFM algorithm provided 3D displacement vectors for each voxel which were used to map tumour voxels on expiration BH CT onto inspiration BH CT images. A thoracic phantom and simulated expiration/inspiration BH CT pairs were used for validation. The 3D OFM was applied to the measured inspiration and expiration BH CT images from one lung cancer and one oesophageal cancer patient. The resulting displacements were plotted in histogram format and analysed to provide insight regarding the tumour motion. The phantom tumour displacement was measured as 1.20 and 2.40 cm with full-width at tenth maximum (FWTM) for the distribution of displacement estimates of 0.008 and 0.006 cm, respectively. The maximum error of any single voxel's motion estimate was 1.1 mm along the z-dimension or approximately one-third of the z-dimension voxel size. The simulated BH CT pairs revealed an rms error of less than 0.25 mm. The displacement of the oesophageal tumours was nonuniform and up to 1.4 cm, this was a new finding. A lung tumour maximum displacement of 2.4 cm was found in the case evaluated. In conclusion, 3D OFM provided an accurate estimation of intrathoracic tumour motion, with estimated errors less than the voxel dimension in a simulated motion phantom study. Surprisingly, oesophageal tumour motion was large and nonuniform, with greatest motion occurring at the gastro-oesophageal junction. Presented at The IASTED Second International Conference on Biomedical Engineering (BioMED 2004), Innsbruck, Austria, 16-18 February 2004.

  6. Electrifying photonic metamaterials for tunable nonlinear optics.

    Science.gov (United States)

    Kang, Lei; Cui, Yonghao; Lan, Shoufeng; Rodrigues, Sean P; Brongersma, Mark L; Cai, Wenshan

    2014-08-11

    Metamaterials have not only enabled unprecedented flexibility in producing unconventional optical properties that are not found in nature, they have also provided exciting potential to create customized nonlinear media with high-order properties correlated to linear behaviour. Two particularly compelling directions are active metamaterials, whose optical properties can be purposely tailored by external stimuli in a reversible manner, and nonlinear metamaterials, which enable intensity-dependent frequency conversion of light waves. Here, by exploring the interaction of these two directions, we leverage the electrical and optical functions simultaneously supported in nanostructured metals and demonstrate electrically controlled nonlinear optical processes from a metamaterial. Both second harmonic generation and optical rectification, enhanced by the resonance behaviour in the metamaterial absorber, are modulated externally with applied voltage signals. Our results reveal an opportunity to exploit optical metamaterials as self-contained, dynamic electro-optic systems with intrinsically embedded electrical functions and optical nonlinearities.

  7. Influence of surface roughness on nonlinear flow behaviors in 3D self-affine rough fractures: Lattice Boltzmann simulations

    Science.gov (United States)

    Wang, Min; Chen, Yi-Feng; Ma, Guo-Wei; Zhou, Jia-Qing; Zhou, Chuang-Bing

    2016-10-01

    This study investigates the impacts of surface roughness on the nonlinear fluid flow through three-dimensional (3D) self-affine rock fractures, whose original surface roughness is decomposed into primary roughness (i.e. the large-scale waviness of the fracture morphology) and secondary roughness (i.e. the small-scale unevenness) with a wavelet analysis technique. A 3D Lattice Boltzmann method (LBM) is adopted to predict the flow physics in rock fractures numerically created with and without consideration of the secondary roughness, respectively. The simulation results show that the primary roughness mostly controls the pressure distribution and fracture flow paths at a large scale, whereas the secondary roughness determines the nonlinear properties of the fluid flow at a local scale. As the pressure gradient increases, the secondary roughness enhances the local complexity of velocity distribution by generating and expanding the eddy flow and back flow regions in the vicinity of asperities. It was found that the Forchheimer's law characterizes well the nonlinear flow behavior in fractures of varying roughness. The inertial effects induced by the primary roughness differ only marginally in fractures with the roughness exponent varying from 0.5 to 0.8, and it is the secondary roughness that significantly enhances the nonlinear flow and leads to earlier onset of nonlinearity. Further examined were the effects of surface roughness on the transmissivity, hydraulic aperture and the tortuosity of flow paths, demonstrating again the dominant role of the secondary roughness, especially for the apparent transmissivity and the equivalent hydraulic aperture at high pressure gradient or high Reynolds number. The results may enhance our understanding of the role of surface roughness in the nonlinear flow behaviors in natural rock fractures.

  8. Extended volume and surface scatterometer for optical characterization of 3D-printed elements

    Science.gov (United States)

    Dannenberg, Florian; Uebeler, Denise; Weiß, Jürgen; Pescoller, Lukas; Weyer, Cornelia; Hahlweg, Cornelius

    2015-09-01

    The use of 3d printing technology seems to be a promising way for low cost prototyping, not only of mechanical, but also of optical components or systems. It is especially useful in applications where customized equipment repeatedly is subject to immediate destruction, as in experimental detonics and the like. Due to the nature of the 3D-printing process, there is a certain inner texture and therefore inhomogeneous optical behaviour to be taken into account, which also indicates mechanical anisotropy. Recent investigations are dedicated to quantification of optical properties of such printed bodies and derivation of corresponding optimization strategies for the printing process. Beside mounting, alignment and illumination means, also refractive and reflective elements are subject to investigation. The proposed measurement methods are based on an imaging nearfield scatterometer for combined volume and surface scatter measurements as proposed in previous papers. In continuation of last year's paper on the use of near field imaging, which basically is a reflective shadowgraph method, for characterization of glossy surfaces like printed matter or laminated material, further developments are discussed. The device has been extended for observation of photoelasticity effects and therefore homogeneity of polarization behaviour. A refined experimental set-up is introduced. Variation of plane of focus and incident angle are used for separation of various the images of the layers of the surface under test, cross and parallel polarization techniques are applied. Practical examples from current research studies are included.

  9. In vivo multimodal nonlinear optical imaging of mucosal tissue

    Science.gov (United States)

    Sun, Ju; Shilagard, Tuya; Bell, Brent; Motamedi, Massoud; Vargas, Gracie

    2004-05-01

    We present a multimodal nonlinear imaging approach to elucidate microstructures and spectroscopic features of oral mucosa and submucosa in vivo. The hamster buccal pouch was imaged using 3-D high resolution multiphoton and second harmonic generation microscopy. The multimodal imaging approach enables colocalization and differentiation of prominent known spectroscopic and structural features such as keratin, epithelial cells, and submucosal collagen at various depths in tissue. Visualization of cellular morphology and epithelial thickness are in excellent agreement with histological observations. These results suggest that multimodal nonlinear optical microscopy can be an effective tool for studying the physiology and pathology of mucosal tissue.

  10. Fiber optic vibration sensor for high-power electric machines realized using 3D printing technology

    Science.gov (United States)

    Igrec, Bojan; Bosiljevac, Marko; Sipus, Zvonimir; Babic, Dubravko; Rudan, Smiljko

    2016-03-01

    The objective of this work was to demonstrate a lightweight and inexpensive fiber-optic vibration sensor, built using 3D printing technology, for high-power electric machines and similar applications. The working principle is based on modulating the light intensity using a blade attached to a bendable membrane. The sensor prototype was manufactured using PolyJet Matrix technology with DM 8515 Grey 35 Polymer. The sensor shows linear response, expected bandwidth (< 150 Hz), and from our measurements we estimated the damping ratio for used polymer to be ζ ≍ 0.019. The developed prototype is simple to assemble, adjust, calibrate and repair.

  11. Nonlinear analysis of chaotic flow in a 3D closed-loop pulsating heat pipe

    CERN Document Server

    Pouryoussefi, S M

    2016-01-01

    Numerical simulation has been conducted for the chaotic flow in a 3D closed-loop pulsating heat pipe (PHP). Heat flux and constant temperature boundary conditions were applied for evaporator and condenser sections, respectively. Water and ethanol were used as working fluids. Volume of Fluid (VOF) method has been employed for two-phase flow simulation. Spectral analysis of temperature time series was carried out using Power Spectrum Density (PSD) method. Existence of dominant peak in PSD diagram indicated periodic or quasi-periodic behavior in temperature oscillations at particular frequencies. Correlation dimension values for ethanol as working fluid was found to be higher than that for water under the same operating conditions. Similar range of Lyapunov exponent values for the PHP with water and ethanol as working fluids indicated strong dependency of Lyapunov exponent to the structure and dimensions of the PHP. An O-ring structure pattern was obtained for reconstructed 3D attractor at periodic or quasi-peri...

  12. An improved input shaping design for an efficient sway control of a nonlinear 3D overhead crane with friction

    Science.gov (United States)

    Maghsoudi, Mohammad Javad; Mohamed, Z.; Sudin, S.; Buyamin, S.; Jaafar, H. I.; Ahmad, S. M.

    2017-08-01

    This paper proposes an improved input shaping scheme for an efficient sway control of a nonlinear three dimensional (3D) overhead crane with friction using the particle swarm optimization (PSO) algorithm. Using this approach, a higher payload sway reduction is obtained as the input shaper is designed based on a complete nonlinear model, as compared to the analytical-based input shaping scheme derived using a linear second order model. Zero Vibration (ZV) and Distributed Zero Vibration (DZV) shapers are designed using both analytical and PSO approaches for sway control of rail and trolley movements. To test the effectiveness of the proposed approach, MATLAB simulations and experiments on a laboratory 3D overhead crane are performed under various conditions involving different cable lengths and sway frequencies. Their performances are studied based on a maximum residual of payload sway and Integrated Absolute Error (IAE) values which indicate total payload sway of the crane. With experiments, the superiority of the proposed approach over the analytical-based is shown by 30-50% reductions of the IAE values for rail and trolley movements, for both ZV and DZV shapers. In addition, simulations results show higher sway reductions with the proposed approach. It is revealed that the proposed PSO-based input shaping design provides higher payload sway reductions of a 3D overhead crane with friction as compared to the commonly designed input shapers.

  13. Nonlinear optics quantum computing with circuit QED.

    Science.gov (United States)

    Adhikari, Prabin; Hafezi, Mohammad; Taylor, J M

    2013-02-08

    One approach to quantum information processing is to use photons as quantum bits and rely on linear optical elements for most operations. However, some optical nonlinearity is necessary to enable universal quantum computing. Here, we suggest a circuit-QED approach to nonlinear optics quantum computing in the microwave regime, including a deterministic two-photon phase gate. Our specific example uses a hybrid quantum system comprising a LC resonator coupled to a superconducting flux qubit to implement a nonlinear coupling. Compared to the self-Kerr nonlinearity, we find that our approach has improved tolerance to noise in the qubit while maintaining fast operation.

  14. Measuring nonlinear stresses generated by defects in 3D colloidal crystals

    CERN Document Server

    Lin, Neil Y C; Schall, Peter; Sethna, James P; Cohen, Itai

    2016-01-01

    The mechanical, structural and functional properties of crystals are determined by their defects and the distribution of stresses surrounding these defects has broad implications for the understanding of transport phenomena. When the defect density rises to levels routinely found in real-world materials, transport is governed by local stresses that are predominantly nonlinear. Such stress fields however, cannot be measured using conventional bulk and local measurement techniques. Here, we report direct and spatially resolved experimental measurements of the nonlinear stresses surrounding colloidal crystalline defect cores, and show that the stresses at vacancy cores generate attractive interactions between them. We also directly visualize the softening of crystalline regions surrounding dislocation cores, and find that stress fluctuations in quiescent polycrystals are uniformly distributed rather than localized at grain boundaries, as is the case in strained atomic polycrystals. Nonlinear stress measurements ...

  15. Design of Organic Nonlinear Optical Materials

    Science.gov (United States)

    1990-06-01

    This project deals with a new approach to designing organic nonlinear optical materials for second harmonic generation based on the use of hydrogen...patterns for even simple organic molecules. For organic nonlinear optical materials this dilemma means that even the most promising organic molecule may

  16. Hydrothermal synthesis, characterization and optical properties of 3D flower like indium sulfide nanostructures

    Science.gov (United States)

    Ghaderi Sheikhi abadi, Parvaneh; Salavati-Niasari, Masoud; Davar, Fatemeh

    2013-01-01

    High-quality and high-yield 3D flower like indium sulfide (In2S3) nanostructures with cubic structure were synthesized by a wet chemical route, without using any surfactant and organic solvents at 160 °C for 12 h, by using InCl3 and 2-aminothiophenol (2-ATP) as starting reagents. The obtained In2S3 with different morphologies and size was characterized by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-vis) spectroscopy. The effects of reaction parameters, such as temperature, precursor concentration and reaction time on the morphology, and particle size of products were investigated. Our experimental results showed that temperature and time reaction played key roles in the final morphology of In2S3. The morphology of In2S3 structures could be changed from one-dimensional (1D) structures to three-dimensional (3D) structures by increasing reaction time to 24 h. In the present study the optical properties 3D In2S3 structures were investigated.

  17. Polymer optical fibers integrated directly into 3D orthogonal woven composites for sensing

    Science.gov (United States)

    Hamouda, Tamer; Seyam, Abdel-Fattah M.; Peters, Kara

    2015-02-01

    This study demonstrates that standard polymer optical fibers (POF) can be directly integrated into composites from 3D orthogonal woven preforms during the weaving process and then serve as in-situ sensors to detect damage due to bending or impact loads. Different composite samples with embedded POF were fabricated of 3D orthogonal woven composites with different parameters namely number of y-/x-layers and x-yarn density. The signal of POF was not affected significantly by the preform structure. During application of resin using VARTM technique, significant drop in backscattering level was observed due to pressure caused by vacuum on the embedded POF. Measurements of POF signal while in the final composites after resin cure indicated that the backscattering level almost returned to the original level of un-embedded POF. The POF responded to application of bending and impact loads to the composite with a reduction in the backscattering level. The backscattering level almost returned back to its original level after removing the bending load until damage was present in the composite. Similar behavior occurred due to impact events. As the POF itself is used as the sensor and can be integrated throughout the composite, large sections of future 3D woven composite structures could be monitored without the need for specialized sensors or complex instrumentation.

  18. 3D optical sectioning with a new hyperspectral confocal fluorescence imaging system.

    Energy Technology Data Exchange (ETDEWEB)

    Nieman, Linda T.; Sinclair, Michael B.; Davidson, George S.; Van Benthem, Mark Hilary; Haaland, David Michael; Timlin, Jerilyn Ann; Sasaki, Darryl Yoshio; Bachand, George David; Jones, Howland D. T.

    2007-02-01

    A novel hyperspectral fluorescence microscope for high-resolution 3D optical sectioning of cells and other structures has been designed, constructed, and used to investigate a number of different problems. We have significantly extended new multivariate curve resolution (MCR) data analysis methods to deconvolve the hyperspectral image data and to rapidly extract quantitative 3D concentration distribution maps of all emitting species. The imaging system has many advantages over current confocal imaging systems including simultaneous monitoring of numerous highly overlapped fluorophores, immunity to autofluorescence or impurity fluorescence, enhanced sensitivity, and dramatically improved accuracy, reliability, and dynamic range. Efficient data compression in the spectral dimension has allowed personal computers to perform quantitative analysis of hyperspectral images of large size without loss of image quality. We have also developed and tested software to perform analysis of time resolved hyperspectral images using trilinear multivariate analysis methods. The new imaging system is an enabling technology for numerous applications including (1) 3D composition mapping analysis of multicomponent processes occurring during host-pathogen interactions, (2) monitoring microfluidic processes, (3) imaging of molecular motors and (4) understanding photosynthetic processes in wild type and mutant Synechocystis cyanobacteria.

  19. High resolution 3D imaging of living cells with sub-optical wavelength phonons

    Science.gov (United States)

    Pérez-Cota, Fernando; Smith, Richard J.; Moradi, Emilia; Marques, Leonel; Webb, Kevin F.; Clark, Matt

    2016-12-01

    Label-free imaging of living cells below the optical diffraction limit poses great challenges for optical microscopy. Biologically relevant structural information remains below the Rayleigh limit and beyond the reach of conventional microscopes. Super-resolution techniques are typically based on the non-linear and stochastic response of fluorescent labels which can be toxic and interfere with cell function. In this paper we present, for the first time, imaging of live cells using sub-optical wavelength phonons. The axial imaging resolution of our system is determined by the acoustic wavelength (λa = λprobe/2n) and not on the NA of the optics allowing sub-optical wavelength acoustic sectioning of samples using the time of flight. The transverse resolution is currently limited to the optical spot size. The contrast mechanism is significantly determined by the mechanical properties of the cells and requires no additional contrast agent, stain or label to image the cell structure. The ability to breach the optical diffraction limit to image living cells acoustically promises to bring a new suite of imaging technologies to bear in answering exigent questions in cell biology and biomedicine.

  20. Multigrid techniques for nonlinear eigenvalue probems: Solutions of a nonlinear Schroedinger eigenvalue problem in 2D and 3D

    Science.gov (United States)

    Costiner, Sorin; Taasan, Shlomo

    1994-01-01

    This paper presents multigrid (MG) techniques for nonlinear eigenvalue problems (EP) and emphasizes an MG algorithm for a nonlinear Schrodinger EP. The algorithm overcomes the mentioned difficulties combining the following techniques: an MG projection coupled with backrotations for separation of solutions and treatment of difficulties related to clusters of close and equal eigenvalues; MG subspace continuation techniques for treatment of the nonlinearity; an MG simultaneous treatment of the eigenvectors at the same time with the nonlinearity and with the global constraints. The simultaneous MG techniques reduce the large number of self consistent iterations to only a few or one MG simultaneous iteration and keep the solutions in a right neighborhood where the algorithm converges fast.

  1. Three-axis distributed fiber optic strain measurement in 3D woven composite structures

    Science.gov (United States)

    Castellucci, Matt; Klute, Sandra; Lally, Evan M.; Froggatt, Mark E.; Lowry, David

    2013-03-01

    Recent advancements in composite materials technologies have broken further from traditional designs and require advanced instrumentation and analysis capabilities. Success or failure is highly dependent on design analysis and manufacturing processes. By monitoring smart structures throughout manufacturing and service life, residual and operational stresses can be assessed and structural integrity maintained. Composite smart structures can be manufactured by integrating fiber optic sensors into existing composite materials processes such as ply layup, filament winding and three-dimensional weaving. In this work optical fiber was integrated into 3D woven composite parts at a commercial woven products manufacturing facility. The fiber was then used to monitor the structures during a VARTM manufacturing process, and subsequent static and dynamic testing. Low cost telecommunications-grade optical fiber acts as the sensor using a high resolution commercial Optical Frequency Domain Reflectometer (OFDR) system providing distributed strain measurement at spatial resolutions as low as 2mm. Strain measurements using the optical fiber sensors are correlated to resistive strain gage measurements during static structural loading.

  2. 3D automatic segmentation method for retinal optical coherence tomography volume data using boundary surface enhancement

    Directory of Open Access Journals (Sweden)

    Yankui Sun

    2016-03-01

    Full Text Available With the introduction of spectral-domain optical coherence tomography (SD-OCT, much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, there is a critical need for the development of three-dimensional (3D segmentation methods for processing these data. We present here a novel 3D automatic segmentation method for retinal OCT volume data. Briefly, to segment a boundary surface, two OCT volume datasets are obtained by using a 3D smoothing filter and a 3D differential filter. Their linear combination is then calculated to generate new volume data with an enhanced boundary surface, where pixel intensity, boundary position information, and intensity changes on both sides of the boundary surface are used simultaneously. Next, preliminary discrete boundary points are detected from the A-Scans of the volume data. Finally, surface smoothness constraints and a dynamic threshold are applied to obtain a smoothed boundary surface by correcting a small number of error points. Our method can extract retinal layer boundary surfaces sequentially with a decreasing search region of volume data. We performed automatic segmentation on eight human OCT volume datasets acquired from a commercial Spectralis OCT system, where each volume of datasets contains 97 OCT B-Scan images with a resolution of 496×512 (each B-Scan comprising 512 A-Scans containing 496 pixels; experimental results show that this method can accurately segment seven layer boundary surfaces in normal as well as some abnormal eyes.

  3. 3D shape measurement of optical free-form surface based on fringe projection

    Science.gov (United States)

    Li, Shaohui; Liu, Shugui; Zhang, Hongwei

    2011-05-01

    Present a novel method of 3D shape measurement of optical free-from surface based on fringe projection. A virtual reference surface is proposed which can be used to improve the detection efficiency and realize the automation of measuring process. Sinusoidal fringe patterns are projected to the high reflected surface of the measured object. The deflection fringe patterns that modulated by the object surface are captured by the CCD camera. The slope information can be obtained by analyzing the relationship between the phase deflectometry and the slope of the object surface. The wave-front reconstruction method is used to reconstruct the surface. With the application of fringe projection technology the accuracy of optical free-form surfaces measurement could reach the level of tens of micrometer or even micrometer.

  4. Mixtures of 3D disperse systems with nano- and micro-particles: Optical characterization

    Directory of Open Access Journals (Sweden)

    Alexandra G. Bezrukova

    2016-12-01

    Full Text Available Multiparameter analysis of simultaneous optical data for systems of nano- and/or micro-particles (3D disperse systems, dispersions, colloids, ensembles by presentation of system characteristics as N-dimensional vectors of optical parameters (ND-vectors can help to elucidate changes in the state of the particles in systems. In this paper, the application of the ND-vector approach is shown on the examples of dispersion mixtures: a mixture of influenza virus particles with albumin proteins (as a model of dispersions at the process of vaccine production; a mixture of coli bacillus and clay dispersions (as natural water model. This approach can serve as an on-line control platform for the management of technological processes with mixtures.

  5. Optical-CT 3D Dosimetry Using Fresnel Lenses with Minimal Refractive-Index Matching Fluid.

    Directory of Open Access Journals (Sweden)

    Steven Bache

    Full Text Available Telecentric optical computed tomography (optical-CT is a state-of-the-art method for visualizing and quantifying 3-dimensional dose distributions in radiochromic dosimeters. In this work a prototype telecentric system (DFOS-Duke Fresnel Optical-CT Scanner is evaluated which incorporates two substantial design changes: the use of Fresnel lenses (reducing lens costs from $10-30K t0 $1-3K and the use of a 'solid tank' (which reduces noise, and the volume of refractively matched fluid from 1 ltr to 10 cc. The efficacy of DFOS was evaluated by direct comparison against commissioned scanners in our lab. Measured dose distributions from all systems were compared against the predicted dose distributions from a commissioned treatment planning system (TPS. Three treatment plans were investigated including a simple four-field box treatment, a multiple small field delivery, and a complex IMRT treatment. Dosimeters were imaged within 2 h post irradiation, using consistent scanning techniques (360 projections acquired at 1 degree intervals, reconstruction at 2mm. DFOS efficacy was evaluated through inspection of dose line-profiles, and 2D and 3D dose and gamma maps. DFOS/TPS gamma pass rates with 3%/3mm dose difference/distance-to-agreement criteria ranged from 89.3% to 92.2%, compared to from 95.6% to 99.0% obtained with the commissioned system. The 3D gamma pass rate between the commissioned system and DFOS was 98.2%. The typical noise rates in DFOS reconstructions were up to 3%, compared to under 2% for the commissioned system. In conclusion, while the introduction of a solid tank proved advantageous with regards to cost and convenience, further work is required to improve the image quality and dose reconstruction accuracy of the new DFOS optical-CT system.

  6. 3-D neurohistology of transparent tongue in health and injury with optical clearing

    Directory of Open Access Journals (Sweden)

    Tzu-En eHua

    2013-10-01

    Full Text Available Tongue receives extensive innervation to perform taste, sensory, and motor functions. Details of the tongue neuroanatomy and its plasticity in response to injury offer insights to investigate tongue neurophysiology and pathophysiology. However, due to the dispersed nature of the neural network, standard histology cannot provide a global view of the innervation. We prepared transparent mouse tongue by optical clearing to reveal the spatial features of the tongue innervation and its remodeling in injury. Immunostaining of neuronal markers, including PGP9.5 (pan-neuronal marker, calcitonin gene-related peptide (sensory nerves, tyrosine hydroxylase (sympathetic nerves, and vesicular acetylcholine transporter (cholinergic parasympathetic nerves and neuromuscular junctions, was combined with vessel painting and nuclear staining to label the tissue network and architecture. The tongue specimens were immersed in the optical-clearing solution to facilitate photon penetration for 3-dimensiontal (3-D confocal microscopy. Taking advantage of the transparent tissue, we simultaneously revealed the tongue microstructure and innervation with subcellular-level resolution. 3-D projection of the papillary neurovascular complex and taste bud innervation was used to demonstrate the spatial features of tongue mucosa and the panoramic imaging approach. In the tongue injury induced by 4-nitroquinoline 1-oxide administration in the drinking water, we observed neural tissue remodeling in response to the changes of mucosal and muscular structures. Neural networks and the neuromuscular junctions were both found rearranged at the peri-lesional region, suggesting the nerve-lesion interactions in response to injury. Overall, this new tongue histological approach provides a useful tool for 3-D imaging of neural tissues to better characterize their roles with the mucosal and muscular components in health and disease.

  7. Pico-projector-based optical sectioning microscopy for 3D chlorophyll fluorescence imaging of mesophyll cells

    Science.gov (United States)

    Chen, Szu-Yu; Hsu, Yu John; Yeh, Chia-Hua; Chen, S.-Wei; Chung, Chien-Han

    2015-03-01

    A pico-projector-based optical sectioning microscope (POSM) was constructed using a pico-projector to generate structured illumination patterns. A net rate of 5.8 × 106 pixel/s and sub-micron spatial resolution in three-dimensions (3D) were achieved. Based on the pico-projector’s flexibility in pattern generation, the characteristics of POSM with different modulation periods and at different imaging depths were measured and discussed. With the application of different modulation periods, 3D chlorophyll fluorescence imaging of mesophyll cells was carried out in freshly plucked leaves of four species without sectioning or staining. For each leaf, an average penetration depth of 120 μm was achieved. Increasing the modulation period along with the increment of imaging depth, optical sectioning images can be obtained with a compromise between the axial resolution and signal-to-noise ratio. After ∼30 min imaging on the same area, photodamage was hardly observed. Taking the advantages of high speed and low damages of POSM, the investigation of the dynamic fluorescence responses to temperature changes was performed under three different treatment temperatures. The three embedded blue, green and red light-emitting diode light sources were applied to observe the responses of the leaves with different wavelength excitation.

  8. Miniaturization of an optical 3D sensor by additive manufacture of metallic mirrors

    Science.gov (United States)

    Sigel, Andre; Merkel, Markus; Heinrich, Andreas

    2017-06-01

    Based on progress in the field of additive manufacturing optical components can now be printed with rapid prototyping technologies. In this contribution the possibilities of rapid prototyping for optical metrology are exemplified by the fabrication of miniaturized reflectors and the construction of a miniaturized metrology system designed for an industrial metrology application. Focusing on the manufacturing and post processing steps the process chain to fabricate the miniaturized mirror is described. This includes an evaluation of the mirror based on roughness measurements. The reflectors are later utilized in a miniaturized sensor system to scan the interior of small pipes. The additively manufactured mirror is used in the metrology system to create a defined sampling signal within the cavity. Thereby the sensor system generates a point cloud of the internal surfaces using a 3D acquisition algorithm based on the laser triangulation principle. Part of this contribution will be the setup, the 3D acquisition and calibration principle as well as an evaluation of the metrology system. To optimize the point cloud acquisition three different hardware setups were designed using different cameras and calibration algorithms. These three approaches are evaluated and compared.

  9. Optical lens-shift design for increasing spatial resolution of 3D ToF cameras

    Science.gov (United States)

    Lietz, Henrik; Hassan, M. Muneeb; Eberhardt, Jörg

    2017-02-01

    Sensor resolution of 3D time-of-flight (ToF) outdoor-capable cameras is strongly limited because of its large pixel dimensions. Computational imaging permits enhancement of the optical system's resolving power without changing physical sensor properties. Super-resolution (SR) algorithms superimpose several sub-pixel-shifted low-resolution (LR) images to overcome the system's limited spatial sampling rate. In this paper, we propose a novel opto-mechanical system to implement sub-pixel shifts by moving an optical lens. This method is more flexible in terms of implementing SR techniques than current sensor-shift approaches. In addition, we describe a SR observation model that has been optimized for the use of LR 3D ToF cameras. A state-of-the-art iteratively reweighted minimization algorithm executes the SR process. It is proven that our method achieves nearly the same resolution increase as if the pixel area would be halved physically. Resolution enhancement is measured objectively for amplitude images of a static object scene.

  10. Optically Clear and Resilient Free-Form μ-Optics 3D-Printed via Ultrafast Laser Lithography

    Science.gov (United States)

    Jonušauskas, Linas; Gailevičius, Darius; Mikoliūnaitė, Lina; Sakalauskas, Danas; Šakirzanovas, Simas; Juodkazis, Saulius; Malinauskas, Mangirdas

    2017-01-01

    We introduce optically clear and resilient free-form micro-optical components of pure (non-photosensitized) organic-inorganic SZ2080 material made by femtosecond 3D laser lithography (3DLL). This is advantageous for rapid printing of 3D micro-/nano-optics, including their integration directly onto optical fibers. A systematic study of the fabrication peculiarities and quality of resultant structures is performed. Comparison of microlens resiliency to continuous wave (CW) and femtosecond pulsed exposure is determined. Experimental results prove that pure SZ2080 is ∼20 fold more resistant to high irradiance as compared with standard lithographic material (SU8) and can sustain up to 1.91 GW/cm2 intensity. 3DLL is a promising manufacturing approach for high-intensity micro-optics for emerging fields in astro-photonics and atto-second pulse generation. Additionally, pyrolysis is employed to homogeneously shrink structures up to 40% by removing organic SZ2080 constituents. This opens a promising route towards downscaling photonic lattices and the creation of mechanically robust glass-ceramic microstructures. PMID:28772389

  11. Optically Clear and Resilient Free-Form µ-Optics 3D-Printed via Ultrafast Laser Lithography.

    Science.gov (United States)

    Jonušauskas, Linas; Gailevičius, Darius; Mikoliūnaitė, Lina; Sakalauskas, Danas; Šakirzanovas, Simas; Juodkazis, Saulius; Malinauskas, Mangirdas

    2017-01-02

    We introduce optically clear and resilient free-form micro-optical components of pure (non-photosensitized) organic-inorganic SZ2080 material made by femtosecond 3D laser lithography (3DLL). This is advantageous for rapid printing of 3D micro-/nano-optics, including their integration directly onto optical fibers. A systematic study of the fabrication peculiarities and quality of resultant structures is performed. Comparison of microlens resiliency to continuous wave (CW) and femtosecond pulsed exposure is determined. Experimental results prove that pure SZ2080 is ∼20 fold more resistant to high irradiance as compared with standard lithographic material (SU8) and can sustain up to 1.91 GW/cm² intensity. 3DLL is a promising manufacturing approach for high-intensity micro-optics for emerging fields in astro-photonics and atto-second pulse generation. Additionally, pyrolysis is employed to homogeneously shrink structures up to 40% by removing organic SZ2080 constituents. This opens a promising route towards downscaling photonic lattices and the creation of mechanically robust glass-ceramic microstructures.

  12. Optically Clear and Resilient Free-Form µ-Optics 3D-Printed via Ultrafast Laser Lithography

    Directory of Open Access Journals (Sweden)

    Linas Jonušauskas

    2017-01-01

    Full Text Available We introduce optically clear and resilient free-form micro-optical components of pure (non-photosensitized organic-inorganic SZ2080 material made by femtosecond 3D laser lithography (3DLL. This is advantageous for rapid printing of 3D micro-/nano-optics, including their integration directly onto optical fibers. A systematic study of the fabrication peculiarities and quality of resultant structures is performed. Comparison of microlens resiliency to continuous wave (CW and femtosecond pulsed exposure is determined. Experimental results prove that pure SZ2080 is ∼20 fold more resistant to high irradiance as compared with standard lithographic material (SU8 and can sustain up to 1.91 GW/cm2 intensity. 3DLL is a promising manufacturing approach for high-intensity micro-optics for emerging fields in astro-photonics and atto-second pulse generation. Additionally, pyrolysis is employed to homogeneously shrink structures up to 40% by removing organic SZ2080 constituents. This opens a promising route towards downscaling photonic lattices and the creation of mechanically robust glass-ceramic microstructures.

  13. Development of a nonlinear 3D solid finite element model for the calculation of bending moments of flexural members

    Institute of Scientific and Technical Information of China (English)

    Jin Wencheng; Zhou Xiaoyong; Li Na

    2008-01-01

    A numerical model is developed in this paper to calculate the bending moments of flexural members through integration in 3D solid finite element analyses according to the nonlinear constitutive model of concrete and the elastoplastic constitutive model of steel, utilizing the stress condition of the cross-section, considering the destruction characteristic of reinforced concrete members, and based on the plane cross-section assumption. The results of this model give good agreement with those of the classical method. Consequently, we can also deduce the corresponding numerical expression for eccentrically loaded members according to the analysis method.

  14. DYNAMICAL ANALYSIS OF A 3-D CHAOTIC SYSTEM WITH ONLY TWO QUADRATIC NONLINEARITIES

    Institute of Scientific and Technical Information of China (English)

    Zeraoulia ELHADJ

    2008-01-01

    The paper reports the dynamical study of a three-dimensional quadratic autonomous chaotic system with only two quadratic nonlinearities, which is a special case of the so-called conjugate Lü system. Basic properties of this system are analyzed by means of Lyapunov exponent spectrum and bifurcation diagram. The analysis shows that the system has complex dynamics with some interesting characteristics in which there are several periodic regions, but each of them has quite different periodic orbits.

  15. Implementation of a 3-D nonlinear MHD calculation on the Intel hypercube

    Energy Technology Data Exchange (ETDEWEB)

    Drake, J.B.; Lawkins, W.F.; Carreras, B.A.; Hicks, H.R.

    1987-08-01

    As part of an exploratory study of the suitability of hypercube multiprocessors for scientific computations, the non-linear magnetohydrodynamics (MHD) code RSF was parallelized for use on an Intel iPSC hypercube. This report presents the numerical algorithm of RSF and the techniques used to obtain parallelism without sacrificing the numerical properties of the serial algorithm. Timing results are presented for a sample problem.

  16. Nonlinear imaging and 3D-mapping of terahertz fields with Kerr media

    CERN Document Server

    Clerici, Matteo; Caspani, Lucia; Peccianti, Marco; Rubino, Eleonora; Razzari, Luca; Légaré, François; Ozaki, Tsuneyuki; Morandotti, Roberto

    2013-01-01

    We investigate the spatially and temporally resolved four-wave mixing of terahertz fields and optical pulses in large band-gap dielectrics, such as diamond. We show that it is possible to perform beam profiling and space-time resolved mapping of terahertz fields with sub-wavelength THz resolution by encoding the spatial information into an optical signal, which can then be recorded by a standard CCD camera.

  17. Nonlinear optical properties of ultrathin metal layers

    DEFF Research Database (Denmark)

    Lysenko, Oleg

    2016-01-01

    . The optical characterization of the plasmonic waveguides is performed using femtosecond and picosecond optical pulses. Two nonlinear optical effects in the strip plasmonic waveguides are experimentally observed and reported. The first effect is the nonlinear power transmission of the plasmonic mode......-order nonlinear susceptibility of the plasmonic mode in the gold strip waveguides significantly depends on the metal layer thickness and laser pulse duration. This dependence is explained in detail in terms of the free-electron temporal dynamics in gold. The third-order nonlinear susceptibility of the gold layer...... duration dependence of the third-order nonlinear susceptibility of gold is calculated in the broad range from tens of femtoseconds to tens of picoseconds using the two-temperature model of the free-electron temporal dynamics of gold, and shows the saturation of the thirdorder nonlinear susceptibility...

  18. Tunable Optical Sources and Synthetic Nonlinear Media: Growth and Characterization of Nonlinear Optical Materials

    Science.gov (United States)

    1992-02-13

    niobate and absolute measurements of nonlinear optical coefficients of six different commonly used nonlinear optical materials. The refractometry data for...applied radiation and is now an established technology for Nd:YAG lasers. Optical parametric oscillation and amplification provide a method of generating...continuously tunable output -3- The relative advantages of nonlinear optical frequency conversion compared to other methods for the generation of near

  19. Fiber based optical tweezers for simultaneous in situ force exertion and measurements in a 3D polyacrylamide gel compartment.

    Science.gov (United States)

    Ti, Chaoyang; Thomas, Gawain M; Ren, Yundong; Zhang, Rui; Wen, Qi; Liu, Yuxiang

    2015-07-01

    Optical tweezers play an important role in biological applications. However, it is difficult for traditional optical tweezers based on objective lenses to work in a three-dimensional (3D) solid far away from the substrate. In this work, we develop a fiber based optical trapping system, namely inclined dual fiber optical tweezers, that can simultaneously apply and measure forces both in water and in a 3D polyacrylamide gel matrix. In addition, we demonstrate in situ, non-invasive characterization of local mechanical properties of polyacrylamide gel by measurements on an embedded bead. The fiber optical tweezers measurements agree well with those of atomic force microscopy (AFM). The inclined dual fiber optical tweezers provide a promising and versatile tool for cell mechanics study in 3D environments.

  20. Nonlinear Synchronization for Automatic Learning of 3D Pose Variability in Human Motion Sequences

    Directory of Open Access Journals (Sweden)

    Mozerov M

    2010-01-01

    Full Text Available A dense matching algorithm that solves the problem of synchronizing prerecorded human motion sequences, which show different speeds and accelerations, is proposed. The approach is based on minimization of MRF energy and solves the problem by using Dynamic Programming. Additionally, an optimal sequence is automatically selected from the input dataset to be a time-scale pattern for all other sequences. The paper utilizes an action specific model which automatically learns the variability of 3D human postures observed in a set of training sequences. The model is trained using the public CMU motion capture dataset for the walking action, and a mean walking performance is automatically learnt. Additionally, statistics about the observed variability of the postures and motion direction are also computed at each time step. The synchronized motion sequences are used to learn a model of human motion for action recognition and full-body tracking purposes.

  1. Simulation of 3D tumor cell growth using nonlinear finite element method.

    Science.gov (United States)

    Dong, Shoubing; Yan, Yannan; Tang, Liqun; Meng, Junping; Jiang, Yi

    2016-01-01

    We propose a novel parallel computing framework for a nonlinear finite element method (FEM)-based cell model and apply it to simulate avascular tumor growth. We derive computation formulas to simplify the simulation and design the basic algorithms. With the increment of the proliferation generations of tumor cells, the FEM elements may become larger and more distorted. Then, we describe a remesh and refinement processing of the distorted or over large finite elements and the parallel implementation based on Message Passing Interface to improve the accuracy and efficiency of the simulation. We demonstrate the feasibility and effectiveness of the FEM model and the parallelization methods in simulations of early tumor growth.

  2. Axial-Stereo 3-D Optical Metrology for Inner Profile of Pipes Using a Scanning Laser Endoscope.

    Science.gov (United States)

    Gong, Yuanzheng; Johnston, Richard S; Melville, C David; Seibel, Eric J

    As the rapid progress in the development of optoelectronic components and computational power, 3D optical metrology becomes more and more popular in manufacturing and quality control due to its flexibility and high speed. However, most of the optical metrology methods are limited to external surfaces. This paper proposed a new approach to measure tiny internal 3D surfaces with a scanning fiber endoscope and axial-stereo vision algorithm. A dense, accurate point cloud of internally machined threads was generated to compare with its corresponding X-ray 3D data as ground truth, and the quantification was analyzed by Iterative Closest Points algorithm.

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

    Science.gov (United States)

    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.

  4. Numerical and Experimental Verification of a 3D Quasi-Optical System

    Directory of Open Access Journals (Sweden)

    Zejian Lu

    2015-01-01

    Full Text Available A modular and efficient Gaussian beam (GB analysis method, incorporating frame-based Gabor transformation, GB reflection, and a 3D GB diffraction technique, was developed to analyze both the reflectors and frequency selective surface (FSS in quasi-optical (QO system. To validate this analysis method, a 3D dual-channel QO system operating at 183 and 325 GHz was designed and tested. The proposed QO system employs two-layer structure with a FSS of perforated hexagonal array transmitting the 325 GHz signal on the top layer while diverting the 183 GHz signal to the bottom layer. Measured results of the system demonstrate that the agreement can be achieved down to −30 dB signal level for both channels in the far field pattern. The discrepancy between the calculation and measurement is within 2 dB in the main beam region (2.5 times −3 dB beamwidth, verifying the effectiveness and accuracy of the proposed method.

  5. 3D micro-optical elements for generation of tightly focused vortex beams

    Directory of Open Access Journals (Sweden)

    Balčytis Armandas

    2015-01-01

    Full Text Available Orbital angular momentum carrying light beams are usedfor optical trapping and manipulation. This emerging trend provides new challenges involving device miniaturization for improved performance and enhanced functionality at the microscale. Here we discus a new fabrication method based on combining the additive 3D structuring capability laser photopolymerization and the substractive sub-wavelength resolution patterning of focused ion beam lithography to produce micro-optical elements capable of compound functionality. As a case in point of this approach binary spiral zone pattern based high numerical aperture micro-lenses capable of generating topological charge carrying tightly focused vortex beams in a single wavefront transformation step are presented. The devices were modelled using finite-difference time-domain simulations, and the theoretical predictions were verified by optically characterizing the propagation properties of light transmitted through the fabricated structures. The resulting devices had focal lengths close to the predicted values of f = 18 µm and f = 13 µm as well as topological charge ℓ dependent vortex focal spot sizes of ~ 1:3 µm and ~ 2:0 µm for ℓ = 1 and ℓ = 2 respectively.

  6. 3D optical phase reconstruction within PMMA samples using a spectral OCT system

    Science.gov (United States)

    Briones-R., Manuel d. J.; De La Torre-Ibarra, Manuel H.; Mendoza Santoyo, Fernando

    2015-08-01

    The optical coherence tomography (OCT) technique has proved to be a useful method in biomedical areas such as ophthalmology, dentistry, dermatology, among many others. In all these applications the main target is to reconstruct the internal structure of the samples from which the physician's expertise may recognize and diagnose the existence of a disease. Nowadays OCT has been applied one step further and is used to study the mechanics of some particular type of materials, where the resulting information involves more than just their internal structure and the measurement of parameters such as displacements, stress and strain. Here we report on a spectral OCT system used to image the internal 3D microstructure and displacement maps from a PMMA (Poly-methyl-methacrylate) sample, subjected to a deformation by a controlled three point bending and tilting. The internal mechanical response of the polymer is shown as consecutive 2D images.

  7. Analytical models of icosahedral shells for 3D optical imaging of viruses

    CERN Document Server

    Jafarpour, Aliakbar

    2014-01-01

    A modulated icosahedral shell with an inclusion is a concise description of many viruses, including recently-discovered large double-stranded DNA ones. Many X-ray scattering patterns of such viruses show major polygonal fringes, which can be reproduced in image reconstruction with a homogeneous icosahedral shell. A key question regarding a low-resolution reconstruction is how to introduce further changes to the 3D profile in an efficient way with only a few parameters. Here, we derive and compile different analytical models of such an object with consideration of practical optical setups and typical structures of such viruses. The benefits of such models include 1) inherent filtering and suppressing different numerical errors of a discrete grid, 2) providing a concise and meaningful set of descriptors for feature extraction in high-throughput classification/sorting and higher-resolution cumulative reconstructions, 3) disentangling (physical) resolution from (numerical) discretization step and having a vector ...

  8. Full optical characterization of autostereoscopic 3D displays using local viewing angle and imaging measurements

    Science.gov (United States)

    Boher, Pierre; Leroux, Thierry; Bignon, Thibault; Collomb-Patton, Véronique

    2012-03-01

    Two commercial auto-stereoscopic 3D displays are characterized a using Fourier optics viewing angle system and an imaging video-luminance-meter. One display has a fixed emissive configuration and the other adapts its emission to the observer position using head tracking. For a fixed emissive condition, three viewing angle measurements are performed at three positions (center, right and left). Qualified monocular and binocular viewing spaces in front of the display are deduced as well as the best working distance. The imaging system is then positioned at this working distance and crosstalk homogeneity on the entire surface of the display is measured. We show that the crosstalk is generally not optimized on all the surface of the display. Display aspect simulation using viewing angle measurements allows understanding better the origin of those crosstalk variations. Local imperfections like scratches and marks generally increase drastically the crosstalk, demonstrating that cleanliness requirements for this type of display are quite critical.

  9. Optical security and anti-counterfeiting using 3D screen printing

    Science.gov (United States)

    Wu, W. H.; Yang, W. K.; Cheng, S. H.; Kuo, M. K.; Lee, H. W.; Chang, C. C.; Jeng, G. R.; Liu, C. P.

    2007-04-01

    This work presents a novel method for optical decrypted key production by screen printing technology. The key is mainly used to decrypt encoded information hidden inside documents containing Moire patterns and integral photographic 3D auto-stereoscopic images as a second-line security file. The proposed method can also be applied as an anti-counterfeiting measure in artistic screening. Decryption is performed by matching the correct angle between the decoding key and the document with a text or a simple geometric pattern. This study presents the theoretical analysis and experimental results of the decoded key production by the best parameter combination of Moire pattern size and screen printing elements. Experimental results reveal that the proposed method can be applied in anti-counterfeit document design for the fast and low-cost production of decryption key.

  10. 3D micro-optical lens scanner made by multi-wafer bonding technology

    Science.gov (United States)

    Bargiel, S.; Gorecki, C.; Barański, M.; Passilly, N.; Wiemer, M.; Jia, C.; Frömel, J.

    2013-03-01

    We present the preliminary design, construction and technology of a microoptical, millimeter-size 3-D microlens scanner, which is a key-component for a number of optical on-chip microscopes with emphasis on the architecture of confocal microscope. The construction of the device relies on the vertical integration of micromachined building blocks: top glass lid, silicon electrostatic comb-drive X-Y and Z microactuators with integrated scanning microlenses, ceramic LTCC spacer, and bottom lid with focusing microlens. All components are connected on the wafer level only by sequential anodic bonding. The technology of through wafer vias is applied to create electrical connections through a stack of wafers. More generally, the presented bonding/connection technologies are also of a great importance for the development of various silicon-based devices based on vertical integration scheme. This approach offers a space-effective integration of complex MOEMS devices and an effective integration of various heterogeneous technologies.

  11. Particle-based optical pressure sensors for 3D pressure mapping.

    Science.gov (United States)

    Banerjee, Niladri; Xie, Yan; Chalaseni, Sandeep; Mastrangelo, Carlos H

    2015-10-01

    This paper presents particle-based optical pressure sensors for in-flow pressure sensing, especially for microfluidic environments. Three generations of pressure sensitive particles have been developed- flat planar particles, particles with integrated retroreflectors and spherical microballoon particles. The first two versions suffer from pressure measurement dependence on particles orientation in 3D space and angle of interrogation. The third generation of microspherical particles with spherical symmetry solves these problems making particle-based manometry in microfluidic environment a viable and efficient methodology. Static and dynamic pressure measurements have been performed in liquid medium for long periods of time in a pressure range of atmospheric to 40 psi. Spherical particles with radius of 12 μm and balloon-wall thickness of 0.5 μm are effective for more than 5 h in this pressure range with an error of less than 5%.

  12. 3D simulations of supernova remnants evolution including non-linear particle acceleration

    CERN Document Server

    Ferrand, Gilles; Ballet, Jean; Teyssier, Romain; Fraschetti, Federico

    2009-01-01

    If a sizeable fraction of the energy of supernova remnant shocks is channeled into energetic particles (commonly identified with Galactic cosmic rays), then the morphological evolution of the remnants must be distinctly modified. Evidence of such modifications has been recently obtained with the Chandra and XMM-Newton X-ray satellites. To investigate these effects, we coupled a semi-analytical kinetic model of shock acceleration with a 3D hydrodynamic code (by means of an effective adiabatic index). This enables us to study the time-dependent compression of the region between the forward and reverse shocks due to the back reaction of accelerated particles, concomitantly with the development of the Rayleigh-Taylor hydrodynamic instability at the contact discontinuity. Density profiles depend critically on the injection level eta of particles: for eta up to about 10^-4 modifications are weak and progressive, for eta of the order of 10^-3 modifications are strong and immediate. Nevertheless, the extension of the...

  13. Numerical estimation of 3D mechanical forces exerted by cells on non-linear materials.

    Science.gov (United States)

    Palacio, J; Jorge-Peñas, A; Muñoz-Barrutia, A; Ortiz-de-Solorzano, C; de Juan-Pardo, E; García-Aznar, J M

    2013-01-04

    The exchange of physical forces in both cell-cell and cell-matrix interactions play a significant role in a variety of physiological and pathological processes, such as cell migration, cancer metastasis, inflammation and wound healing. Therefore, great interest exists in accurately quantifying the forces that cells exert on their substrate during migration. Traction Force Microscopy (TFM) is the most widely used method for measuring cell traction forces. Several mathematical techniques have been developed to estimate forces from TFM experiments. However, certain simplifications are commonly assumed, such as linear elasticity of the materials and/or free geometries, which in some cases may lead to inaccurate results. Here, cellular forces are numerically estimated by solving a minimization problem that combines multiple non-linear FEM solutions. Our simulations, free from constraints on the geometrical and the mechanical conditions, show that forces are predicted with higher accuracy than when using the standard approaches.

  14. 3-D Model of Broadband Emission from Supernova Remnants Undergoing Non-linear Diffusive Shock Acceleration

    CERN Document Server

    Lee, Shiu-Hang; Ellison, Donald C

    2008-01-01

    We present a 3-dimensional model of supernova remnants (SNRs) where the hydrodynamical evolution of the remnant is modeled consistently with nonlinear diffusive shock acceleration occuring at the outer blast wave. The model includes particle escape and diffusion outside of the forward shock, and particle interactions with arbitrary distributions of external ambient material, such as molecular clouds. We include synchrotron emission and cooling, bremsstrahlung radiation, neutral pion production, inverse-Compton (IC), and Coulomb energy-loss. Boardband spectra have been calculated for typical parameters including dense regions of gas external to a 1000 year old SNR. In this paper, we describe the details of our model but do not attempt a detailed fit to any specific remnant. We also do not include magnetic field amplification (MFA), even though this effect may be important in some young remnants. In this first presentation of the model we don't attempt a detailed fit to any specific remnant. Our aim is to devel...

  15. Intra-retinal layer segmentation of 3D optical coherence tomography using coarse grained diffusion map.

    Science.gov (United States)

    Kafieh, Raheleh; Rabbani, Hossein; Abramoff, Michael D; Sonka, Milan

    2013-12-01

    Optical coherence tomography (OCT) is a powerful and noninvasive method for retinal imaging. In this paper, we introduce a fast segmentation method based on a new variant of spectral graph theory named diffusion maps. The research is performed on spectral domain (SD) OCT images depicting macular and optic nerve head appearance. The presented approach does not require edge-based image information in localizing most of boundaries and relies on regional image texture. Consequently, the proposed method demonstrates robustness in situations of low image contrast or poor layer-to-layer image gradients. Diffusion mapping applied to 2D and 3D OCT datasets is composed of two steps, one for partitioning the data into important and less important sections, and another one for localization of internal layers. In the first step, the pixels/voxels are grouped in rectangular/cubic sets to form a graph node. The weights of the graph are calculated based on geometric distances between pixels/voxels and differences of their mean intensity. The first diffusion map clusters the data into three parts, the second of which is the area of interest. The other two sections are eliminated from the remaining calculations. In the second step, the remaining area is subjected to another diffusion map assessment and the internal layers are localized based on their textural similarities. The proposed method was tested on 23 datasets from two patient groups (glaucoma and normals). The mean unsigned border positioning errors (mean ± SD) was 8.52 ± 3.13 and 7.56 ± 2.95 μm for the 2D and 3D methods, respectively.

  16. Seismic Hazard Maps for Seattle, Washington, Incorporating 3D Sedimentary Basin Effects, Nonlinear Site Response, and Rupture Directivity

    Science.gov (United States)

    Frankel, Arthur D.; Stephenson, William J.; Carver, David L.; Williams, Robert A.; Odum, Jack K.; Rhea, Susan

    2007-01-01

    This report presents probabilistic seismic hazard maps for Seattle, Washington, based on over 500 3D simulations of ground motions from scenario earthquakes. These maps include 3D sedimentary basin effects and rupture directivity. Nonlinear site response for soft-soil sites of fill and alluvium was also applied in the maps. The report describes the methodology for incorporating source and site dependent amplification factors into a probabilistic seismic hazard calculation. 3D simulations were conducted for the various earthquake sources that can affect Seattle: Seattle fault zone, Cascadia subduction zone, South Whidbey Island fault, and background shallow and deep earthquakes. The maps presented in this document used essentially the same set of faults and distributed-earthquake sources as in the 2002 national seismic hazard maps. The 3D velocity model utilized in the simulations was validated by modeling the amplitudes and waveforms of observed seismograms from five earthquakes in the region, including the 2001 M6.8 Nisqually earthquake. The probabilistic seismic hazard maps presented here depict 1 Hz response spectral accelerations with 10%, 5%, and 2% probabilities of exceedance in 50 years. The maps are based on determinations of seismic hazard for 7236 sites with a spacing of 280 m. The maps show that the most hazardous locations for this frequency band (around 1 Hz) are soft-soil sites (fill and alluvium) within the Seattle basin and along the inferred trace of the frontal fault of the Seattle fault zone. The next highest hazard is typically found for soft-soil sites in the Duwamish Valley south of the Seattle basin. In general, stiff-soil sites in the Seattle basin exhibit higher hazard than stiff-soil sites outside the basin. Sites with shallow bedrock outside the Seattle basin have the lowest estimated hazard for this frequency band.

  17. Oscillating optical tweezer-based 3-D confocal microrheometer for investigating the intracellular micromechanics and structures

    Science.gov (United States)

    Ou-Yang, H. D.; Rickter, E. A.; Pu, C.; Latinovic, O.; Kumar, A.; Mengistu, M.; Lowe-Krentz, L.; Chien, S.

    2005-08-01

    Mechanical properties of living biological cells are important for cells to maintain their shapes, support mechanical stresses and move through tissue matrix. The use of optical tweezers to measure micromechanical properties of cells has recently made significant progresses. This paper presents a new approach, the oscillating optical tweezer cytorheometer (OOTC), which takes advantage of the coherent detection of harmonically modulated particle motions by a lock-in amplifier to increase sensitivity, temporal resolution and simplicity. We demonstrate that OOTC can measure the dynamic mechanical modulus in the frequency range of 0.1-6,000 Hz at a rate as fast as 1 data point per second with submicron spatial resolution. More importantly, OOTC is capable of distinguishing the intrinsic non-random temporal variations from random fluctuations due to Brownian motion; this capability, not achievable by conventional approaches, is particular useful because living systems are highly dynamic and often exhibit non-thermal, rhythmic behavior in a broad time scale from a fraction of a second to hours or days. Although OOTC is effective in measuring the intracellular micromechanical properties, unless we can visualize the cytoskeleton in situ, the mechanical property data would only be as informative as that of "Blind men and the Elephant". To solve this problem, we take two steps, the first, to use of fluorescent imaging to identify the granular structures trapped by optical tweezers, and second, to integrate OOTC with 3-D confocal microscopy so we can take simultaneous, in situ measurements of the micromechanics and intracellular structure in living cells. In this paper, we discuss examples of applying the oscillating tweezer-based cytorheometer for investigating cultured bovine endothelial cells, the identification of caveolae as some of the granular structures in the cell as well as our approach to integrate optical tweezers with a spinning disk confocal microscope.

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

    Science.gov (United States)

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

    2012-03-01

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

  19. Metamaterials with tailored nonlinear optical response.

    Science.gov (United States)

    Husu, Hannu; Siikanen, Roope; Mäkitalo, Jouni; Lehtolahti, Joonas; Laukkanen, Janne; Kuittinen, Markku; Kauranen, Martti

    2012-02-08

    We demonstrate that the second-order nonlinear optical response of noncentrosymmetric metal nanoparticles (metamolecules) can be efficiently controlled by their mutual ordering in an array. Two samples with minor change in ordering have nonlinear responses differing by a factor of up to 50. The results arise from polarization-dependent plasmonic resonances modified by long-range coupling associated with metamolecular ordering. The approach opens new ways for tailoring the nonlinear responses of metamaterials and their tensorial properties.

  20. Non-linear 3D evaluation of different oral implant-abutment connections.

    Science.gov (United States)

    Streckbein, P; Streckbein, R G; Wilbrand, J F; Malik, C Y; Schaaf, H; Howaldt, H P; Flach, M

    2012-12-01

    Micro-gaps and osseous overload in the implant-abutment connection are the most common causes of peri-implant bone resorption and implant failure. These undesirable events can be visualized on standardized three-dimensional finite element models and by radiographic methods. The present study investigated the influence of 7 available implant systems (Ankylos, Astra, Bego, Brånemark, Camlog, Straumann, and Xive) with different implant-abutment connections on bone overload and the appearance of micro-gaps in vitro. The individual geometries of the implants were transferred to three-dimensional finite element models. In a non-linear analysis considering the pre-loading of the occlusion screw, friction between the implant and abutment, the influence of the cone angle on bone strain, and the appearance of micro-gaps were determined. Increased bone strains were correlated with small (< 15°) cone angles. Conical implant-abutment connections efficiently avoided micro-gaps but had a negative effect on peri-implant bone strain. Bone strain was reduced in implants with greater wall thickness (Ankylos) or a smaller cone angle (Bego). The results of our in silico study provide a solid basis for the reduction of peri-implant bone strain and micro-gaps in the implant-abutment connection to improve long-term stability.

  1. Nonlinear soliton matching between optical fibers

    DEFF Research Database (Denmark)

    Agger, Christian; Sørensen, Simon Toft; Thomsen, Carsten L.

    2011-01-01

    In this Letter, we propose a generic nonlinear coupling coefficient, η2 NL ¼ ηjγ=β2jfiber2=jγ=β2jfiber1, which gives a quantitative measure for the efficiency of nonlinear matching of optical fibers by describing how a fundamental soliton couples from one fiber into another. Specifically, we use η...

  2. All-optical switching in optically induced nonlinear waveguide couplers

    Energy Technology Data Exchange (ETDEWEB)

    Diebel, Falko, E-mail: falko.diebel@uni-muenster.de; Boguslawski, Martin; Rose, Patrick; Denz, Cornelia [Institut für Angewandte Physik and Center for Nonlinear Science (CeNoS), Westfälische Wilhelms-Universität Münster, 48149 Münster (Germany); Leykam, Daniel; Desyatnikov, Anton S. [Nonlinear Physics Centre, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia)

    2014-06-30

    We experimentally demonstrate all-optical vortex switching in nonlinear coupled waveguide arrays optically induced in photorefractive media. Our technique is based on multiplexing of nondiffracting Bessel beams to induce various types of waveguide configurations. Using double- and quadruple-well potentials, we demonstrate precise control over the coupling strength between waveguides, the linear and nonlinear dynamics and symmetry-breaking bifurcations of guided light, and a power-controlled optical vortex switch.

  3. Development of Organic Nonlinear Optical Materials

    Science.gov (United States)

    1992-10-22

    10 SOVRCE Of FUNO#NG NUM#E*S DM J .j PROGRAM PR0jECT TA5. ~ *0. I1I TITLE &Vila* So.Ivety ClaUMC400NJ Development of Organic NonLinear Optical Materials (U...0102-LF-014-6603 UNCLASSIFIED (U) AFOSR Contract: F4962040-C 0097 FINAL REPORT Development of Organic Nonlinear Optical Materials by J. Sounnk IL

  4. Nonlinear optical localization in embedded chalcogenide waveguide arrays

    Directory of Open Access Journals (Sweden)

    Mingshan Li

    2014-05-01

    Full Text Available We report the nonlinear optical localization in an embedded waveguide array fabricated in chalcogenide glass. The array, which consists of seven waveguides with circularly symmetric cross sections, is realized by ultrafast laser writing. Light propagation in the chalcogenide waveguide array is studied with near infrared laser pulses centered at 1040 nm. The peak intensity required for nonlinear localization for the 1-cm long waveguide array was 35.1 GW/cm2, using 10-nJ pulses with 300-fs pulse width, which is 70 times lower than that reported in fused silica waveguide arrays and with over 7 times shorter interaction distance. Results reported in this paper demonstrated that ultrafast laser writing is a viable tool to produce 3D all-optical switching waveguide circuits in chalcogenide glass.

  5. Label-free optical detection of cells grown in 3D silicon microstructures.

    Science.gov (United States)

    Merlo, Sabina; Carpignano, Francesca; Silva, Gloria; Aredia, Francesca; Scovassi, A Ivana; Mazzini, Giuliano; Surdo, Salvatore; Barillaro, Giuseppe

    2013-08-21

    We demonstrate high aspect-ratio photonic crystals that could serve as three-dimensional (3D) microincubators for cell culture and also provide label-free optical detection of the cells. The investigated microstructures, fabricated by electrochemical micromachining of standard silicon wafers, consist of periodic arrays of silicon walls separated by narrow deeply etched air-gaps (50 μm high and 5 μm wide) and feature the typical spectral properties of photonic crystals in the wavelength range 1.0-1.7 μm: their spectral reflectivity is characterized by wavelength regions where reflectivity is high (photonic bandgaps), separated by narrow wavelength regions where reflectivity is very low. In this work, we show that the presence of cells, grown inside the gaps, strongly affects light propagation across the photonic crystal and, therefore, its spectral reflectivity. Exploiting a label-free optical detection method, based on a fiberoptic setup, we are able to probe the extension of cells adherent to the vertical silicon walls with a non-invasive direct testing. In particular, the intensity ratio at two wavelengths is the experimental parameter that can be well correlated to the cell spreading on the silicon wall inside the gaps.

  6. A 3D approach to reconstruct continuous optical images using lidar and MODIS

    Institute of Scientific and Technical Information of China (English)

    HuaGuo; Huang; Jun; Lian

    2015-01-01

    Background: Monitoring forest health and biomass for changes over time in the global environment requires the provision of continuous satellite images. However, optical images of land surfaces are generally contaminated when clouds are present or rain occurs.Methods: To estimate the actual reflectance of land surfaces masked by clouds and potential rain, 3D simulations by the RAPID radiative transfer model were proposed and conducted on a forest farm dominated by birch and larch in Genhe City, Da Xing’An Ling Mountain in Inner Mongolia, China. The canopy height model(CHM) from lidar data were used to extract individual tree structures(location, height, crown width). Field measurements related tree height to diameter of breast height(DBH), lowest branch height and leaf area index(LAI). Series of Landsat images were used to classify tree species and land cover. MODIS LAI products were used to estimate the LAI of individual trees. Combining all these input variables to drive RAPID, high-resolution optical remote sensing images were simulated and validated with available satellite images.Results: Evaluations on spatial texture, spectral values and directional reflectance were conducted to show comparable results.Conclusions: The study provides a proof-of-concept approach to link lidar and MODIS data in the parameterization of RAPID models for high temporal and spatial resolutions of image reconstruction in forest dominated areas.

  7. A 3D approach to reconstruct continuous optical images using lidar and MODIS

    Directory of Open Access Journals (Sweden)

    HuaGuo Huang

    2015-06-01

    Full Text Available Background Monitoring forest health and biomass for changes over time in the global environment requires the provision of continuous satellite images. However, optical images of land surfaces are generally contaminated when clouds are present or rain occurs. Methods To estimate the actual reflectance of land surfaces masked by clouds and potential rain, 3D simulations by the RAPID radiative transfer model were proposed and conducted on a forest farm dominated by birch and larch in Genhe City, DaXing’AnLing Mountain in Inner Mongolia, China. The canopy height model (CHM from lidar data were used to extract individual tree structures (location, height, crown width. Field measurements related tree height to diameter of breast height (DBH, lowest branch height and leaf area index (LAI. Series of Landsat images were used to classify tree species and land cover. MODIS LAI products were used to estimate the LAI of individual trees. Combining all these input variables to drive RAPID, high-resolution optical remote sensing images were simulated and validated with available satellite images. Results Evaluations on spatial texture, spectral values and directional reflectance were conducted to show comparable results. Conclusions The study provides a proof-of-concept approach to link lidar and MODIS data in the parameterization of RAPID models for high temporal and spatial resolutions of image reconstruction in forest dominated areas.

  8. 3D optical simulation formalism OPTOS for textured silicon solar cells.

    Science.gov (United States)

    Tucher, Nico; Eisenlohr, Johannes; Kiefel, Peter; Höhn, Oliver; Hauser, Hubert; Peters, Marius; Müller, Claas; Goldschmidt, Jan Christoph; Bläsi, Benedikt

    2015-11-30

    In this paper we introduce the three-dimensional formulation of the OPTOS formalism, a matrix-based method that allows for the efficient simulation of non-coherent light propagation and absorption in thick textured sheets. As application examples, we calculate the absorptance of solar cells featuring textures on front and rear side with different feature sizes operating in different optical regimes. A discretization of polar and azimuth angle enables a three-dimensional description of systems with arbitrary surface textures. We present redistribution matrices for 3D surface textures, including pyramidal textures, binary crossed gratings and a Lambertian scatterer. The results of the OPTOS simulations for silicon sheets with different combinations of these surfaces are in accordance with both optical measurements and results based on established simulation methods like ray tracing. Using OPTOS, we show that the integration of a diffractive grating at the rear side of a silicon solar cell featuring a pyramidal front side results in absorption close to the Yablonovitch Limit enhancing the photocurrent density by 0.6 mA/cm2 for a 200 µm thick cell.

  9. Nonlinear rheology in ASPECT: benchmarking and an application to 3D subduction

    Science.gov (United States)

    Glerum, Anne; Thieulot, Cedric; Fraters, Menno; Spakman, Wim

    2014-05-01

    ASPECT (Advanced Solver for Problems in Earth's ConvecTion) is a promising new code designed for modelling thermal convection in the mantle (Kronbichler et al. 2012). The massively parallel code uses state-of-the-art numerical methods, such as high performance solvers and adaptive mesh refinement. It builds on tried-and-well-tested libraries and works with plug-ins allowing easy extension to fine-tune it to the user's specific needs. We extended the code by implementing a frictional plasticity criterion that can be combined with a viscous creep rheology, allowing for thermo-mechanically coupled visco-plastic flow. This way we can accommodate for the nonlinear behavior of the Earth's materials and incorporate for instance the localization of deformation through plastic yielding. This has been shown to be of great importance for modelling lithosphere deformation. Three well-known benchmarks are used to test and validate our implementation of plasticity: the punch benchmark (e.g. Thieulot et al. 2008), which considers the indentation of a perfectly plastic material and allows for comparison with an analytical solution; the brick benchmark (Kaus 2010), performed in both a compressional and tensional regime with shear band angles bounded by results of other codes and theory; and the sandbox experiment by Buiter et al. (2006) modelling the time evolution of the extension of viscous and plastic layers in the presence of a free surface. We further showcase ASPECT's capabilities with a more geodynamical application: the subduction of an oceanic plate in a three-dimensional thermo-mechanically coupled system. We compare the use of nonlinear rheologies versus that of constant mantle and plate viscosities with an adaptation of the subducting/overriding plate setup of Schellart and Moresi (2013). These models also demonstrate how the adaptive mesh refinement allows for high resolutions locally while the code remains computationally efficient even in the presence of large

  10. Dental non-linear image registration and collection method with 3D reconstruction and change detection

    Science.gov (United States)

    Rahmes, Mark; Fagan, Dean; Lemieux, George

    2017-03-01

    The capability of a software algorithm to automatically align same-patient dental bitewing and panoramic x-rays over time is complicated by differences in collection perspectives. We successfully used image correlation with an affine transform for each pixel to discover common image borders, followed by a non-linear homography perspective adjustment to closely align the images. However, significant improvements in image registration could be realized if images were collected from the same perspective, thus facilitating change analysis. The perspective differences due to current dental image collection devices are so significant that straightforward change analysis is not possible. To address this, a new custom dental tray could be used to provide the standard reference needed for consistent positioning of a patient's mouth. Similar to sports mouth guards, the dental tray could be fabricated in standard sizes from plastic and use integrated electronics that have been miniaturized. In addition, the x-ray source needs to be consistently positioned in order to collect images with similar angles and scales. Solving this pose correction is similar to solving for collection angle in aerial imagery for change detection. A standard collection system would provide a method for consistent source positioning using real-time sensor position feedback from a digital x-ray image reference. Automated, robotic sensor positioning could replace manual adjustments. Given an image set from a standard collection, a disparity map between images can be created using parallax from overlapping viewpoints to enable change detection. This perspective data can be rectified and used to create a three-dimensional dental model reconstruction.

  11. 3-D Model of Broadband Emission from Supernova Remnants Undergoing Non-linear Diffusive Shock Acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Shiu-Hang; Kamae, Tuneyoshi; Ellison, Donald C.

    2008-07-02

    We present a 3-dimensional model of supernova remnants (SNRs) where the hydrodynamical evolution of the remnant is modeled consistently with nonlinear diffusive shock acceleration occurring at the outer blast wave. The model includes particle escape and diffusion outside of the forward shock, and particle interactions with arbitrary distributions of external ambient material, such as molecular clouds. We include synchrotron emission and cooling, bremsstrahlung radiation, neutral pion production, inverse-Compton (IC), and Coulomb energy-loss. Boardband spectra have been calculated for typical parameters including dense regions of gas external to a 1000 year old SNR. In this paper, we describe the details of our model but do not attempt a detailed fit to any specific remnant. We also do not include magnetic field amplification (MFA), even though this effect may be important in some young remnants. In this first presentation of the model we don't attempt a detailed fit to any specific remnant. Our aim is to develop a flexible platform, which can be generalized to include effects such as MFA, and which can be easily adapted to various SNR environments, including Type Ia SNRs, which explode in a constant density medium, and Type II SNRs, which explode in a pre-supernova wind. When applied to a specific SNR, our model will predict cosmic-ray spectra and multi-wavelength morphology in projected images for instruments with varying spatial and spectral resolutions. We show examples of these spectra and images and emphasize the importance of measurements in the hard X-ray, GeV, and TeV gamma-ray bands for investigating key ingredients in the acceleration mechanism, and for deducing whether or not TeV emission is produced by IC from electrons or pion-decay from protons.

  12. Beyond optical molasses: 3D raman sideband cooling of atomic cesium to high phase-space density

    Science.gov (United States)

    Kerman; Vuletic; Chin; Chu

    2000-01-17

    We demonstrate a simple, general purpose method to cool neutral atoms. A sample containing 3x10(8) cesium atoms prepared in a magneto-optical trap is cooled and simultaneously spin polarized in 10 ms at a density of 1.1x10(11) cm (-3) to a phase space density nlambda(3)(dB) = 1/500, which is almost 3 orders of magnitude higher than attainable in free space with optical molasses. The technique is based on 3D degenerate Raman sideband cooling in optical lattices and remains efficient even at densities where the mean lattice site occupation is close to unity.

  13. Optical Nonlinearities and Ultrafast Carrier Dynamics in Semiconductor Quantum Dots

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, V.; McBranch, D.; Schwarz, C.

    1998-08-10

    Low-dimensional semiconductors have attracted great interest due to the potential for tailoring their linear and nonlinear optical properties over a wide-range. Semiconductor nanocrystals (NC's) represent a class of quasi-zero-dimensional objects or quantum dots. Due to quantum cordhement and a large surface-to-volume ratio, the linear and nonlinear optical properties, and the carrier dynamics in NC's are significantly different horn those in bulk materials. napping at surface states can lead to a fast depopulation of quantized states, accompanied by charge separation and generation of local fields which significantly modifies the nonlinear optical response in NC's. 3D carrier confinement also has a drastic effect on the energy relaxation dynamics. In strongly confined NC's, the energy-level spacing can greatly exceed typical phonon energies. This has been expected to significantly inhibit phonon-related mechanisms for energy losses, an effect referred to as a phonon bottleneck. It has been suggested recently that the phonon bottleneck in 3D-confined systems can be removed due to enhanced role of Auger-type interactions. In this paper we report femtosecond (fs) studies of ultrafast optical nonlinearities, and energy relaxation and trap ping dynamics in three types of quantum-dot systems: semiconductor NC/glass composites made by high temperature precipitation, ion-implanted NC's, and colloidal NC'S. Comparison of ultrafast data for different samples allows us to separate effects being intrinsic to quantum dots from those related to lattice imperfections and interface properties.

  14. Real-time 3D Fourier-domain optical coherence tomography guided microvascular anastomosis

    Science.gov (United States)

    Huang, Yong; Ibrahim, Zuhaib; Lee, W. P. A.; Brandacher, Gerald; Kang, Jin U.

    2013-03-01

    Vascular and microvascular anastomosis is considered to be the foundation of plastic and reconstructive surgery, hand surgery, transplant surgery, vascular surgery and cardiac surgery. In the last two decades innovative techniques, such as vascular coupling devices, thermo-reversible poloxamers and suture-less cuff have been introduced. Intra-operative surgical guidance using a surgical imaging modality that provides in-depth view and 3D imaging can improve outcome following both conventional and innovative anastomosis techniques. Optical coherence tomography (OCT) is a noninvasive high-resolution (micron level), high-speed, 3D imaging modality that has been adopted widely in biomedical and clinical applications. In this work we performed a proof-of-concept evaluation study of OCT as an assisted intraoperative and post-operative imaging modality for microvascular anastomosis of rodent femoral vessels. The OCT imaging modality provided lateral resolution of 12 μm and 3.0 μm axial resolution in air and 0.27 volume/s imaging speed, which could provide the surgeon with clearly visualized vessel lumen wall and suture needle position relative to the vessel during intraoperative imaging. Graphics processing unit (GPU) accelerated phase-resolved Doppler OCT (PRDOCT) imaging of the surgical site was performed as a post-operative evaluation of the anastomosed vessels and to visualize the blood flow and thrombus formation. This information could help surgeons improve surgical precision in this highly challenging anastomosis of rodent vessels with diameter less than 0.5 mm. Our imaging modality could not only detect accidental suture through the back wall of lumen but also promptly diagnose and predict thrombosis immediately after reperfusion. Hence, real-time OCT can assist in decision-making process intra-operatively and avoid post-operative complications.

  15. Optical Measurement of Micromechanics and Structure in a 3D Fibrin Extracellular Matrix

    Science.gov (United States)

    Kotlarchyk, Maxwell Aaron

    2011-07-01

    In recent years, a significant number of studies have focused on linking substrate mechanics to cell function using standard methodologies to characterize the bulk properties of the hydrogel substrates. However, current understanding of the correlations between the microstructural mechanical properties of hydrogels and cell function in 3D is poor, in part because of a lack of appropriate techniques. Methods for tuning extracellular matrix (ECM) mechanics in 3D cell culture that rely on increasing the concentration of either protein or cross-linking molecules fail to control important parameters such as pore size, ligand density, and molecular diffusivity. Alternatively, ECM stiffness can be modulated independently from protein concentration by mechanically loading the ECM. We have developed an optical tweezers-based microrheology system to investigate the fundamental role of ECM mechanical properties in determining cellular behavior. Further, this thesis outlines the development of a novel device for generating stiffness gradients in naturally derived ECMs, where stiffness is tuned by inducing strain, while local structure and mechanical properties are directly determined by laser tweezers-based passive and active microrheology respectively. Hydrogel substrates polymerized within 35 mm diameter Petri dishes are strained non-uniformly by the precise rotation of an embedded cylindrical post, and exhibit a position-dependent stiffness with little to no modulation of local mesh geometry. Here we present microrheological studies in the context of fibrin hydrogels. Microrheology and confocal imaging were used to directly measure local changes in micromechanics and structure respectively in unstrained hydrogels of increasing fibrinogen concentration, as well as in our strain gradient device, in which the concentration of fibrinogen is held constant. Orbital particle tracking, and raster image correlation analysis are used to quantify changes in fibrin mechanics on the

  16. Multimodal photoacoustic and optical coherence tomography scanner using an all optical detection scheme for 3D morphological skin imaging.

    Science.gov (United States)

    Zhang, Edward Z; Povazay, Boris; Laufer, Jan; Alex, Aneesh; Hofer, Bernd; Pedley, Barbara; Glittenberg, Carl; Treeby, Bradley; Cox, Ben; Beard, Paul; Drexler, Wolfgang

    2011-08-01

    A noninvasive, multimodal photoacoustic and optical coherence tomography (PAT/OCT) scanner for three-dimensional in vivo (3D) skin imaging is described. The system employs an integrated, all optical detection scheme for both modalities in backward mode utilizing a shared 2D optical scanner with a field-of-view of ~13 × 13 mm(2). The photoacoustic waves were detected using a Fabry Perot polymer film ultrasound sensor placed on the surface of the skin. The sensor is transparent in the spectral range 590-1200 nm. This permits the photoacoustic excitation beam (670-680 nm) and the OCT probe beam (1050 nm) to be transmitted through the sensor head and into the underlying tissue thus providing a backward mode imaging configuration. The respective OCT and PAT axial resolutions were 8 and 20 µm and the lateral resolutions were 18 and 50-100 µm. The system provides greater penetration depth than previous combined PA/OCT devices due to the longer wavelength of the OCT beam (1050 nm rather than 829-870 nm) and by operating in the tomographic rather than the optical resolution mode of photoacoustic imaging. Three-dimensional in vivo images of the vasculature and the surrounding tissue micro-morphology in murine and human skin were acquired. These studies demonstrated the complementary contrast and tissue information provided by each modality for high-resolution 3D imaging of vascular structures to depths of up to 5 mm. Potential applications include characterizing skin conditions such as tumors, vascular lesions, soft tissue damage such as burns and wounds, inflammatory conditions such as dermatitis and other superficial tissue abnormalities.

  17. Adaptive backstepping control, synchronization and circuit simulation of a 3-D novel jerk chaotic system with two hyperbolic sinusoidal nonlinearities

    Directory of Open Access Journals (Sweden)

    Vaidyanathan Sundarapandian

    2014-09-01

    Full Text Available In this research work, a six-term 3-D novel jerk chaotic system with two hyperbolic sinusoidal nonlinearities has been proposed, and its qualitative properties have been detailed. The Lyapunov exponents of the novel jerk system are obtained as L1 = 0.07765,L2 = 0, and L3 = −0.87912. The Kaplan-Yorke dimension of the novel jerk system is obtained as DKY = 2.08833. Next, an adaptive backstepping controller is designed to stabilize the novel jerk chaotic system with two unknown parameters. Moreover, an adaptive backstepping controller is designed to achieve complete chaos synchronization of the identical novel jerk chaotic systems with two unknown parameters. Finally, an electronic circuit realization of the novel jerk chaotic system using Spice is presented in detail to confirm the feasibility of the theoretical model

  18. A 3-D Novel Highly Chaotic System with Four Quadratic Nonlinearities, its Adaptive Control and Anti-Synchronization with Unknown Parameters

    OpenAIRE

    Vaidyanathan, S.

    2014-01-01

    This research work proposes a seven-term 3-D novel dissipative chaotic system with four quadratic nonlinearities. The Lyapunov exponents of the 3-D novel chaotic system are obtained as L1 = 11.36204, L2 = 0 and L3 = –47.80208. Since the sum of the Lyapunov exponents is negative, the 3-D novel chaotic system is dissipative. Also, the Kaplan-Yorke dimension of the 3-D novel chaotic system is obtained as DKY = 2.23769. The maximal Lyapunov exponent (MLE) of the novel chaotic system i...

  19. 3D non-linear inversion of magnetic anomalies caused by prismatic bodies using differential evolution algorithm

    Science.gov (United States)

    Balkaya, Çağlayan; Ekinci, Yunus Levent; Göktürkler, Gökhan; Turan, Seçil

    2017-01-01

    3D non-linear inversion of total field magnetic anomalies caused by vertical-sided prismatic bodies has been achieved by differential evolution (DE), which is one of the population-based evolutionary algorithms. We have demonstrated the efficiency of the algorithm on both synthetic and field magnetic anomalies by estimating horizontal distances from the origin in both north and east directions, depths to the top and bottom of the bodies, inclination and declination angles of the magnetization, and intensity of magnetization of the causative bodies. In the synthetic anomaly case, we have considered both noise-free and noisy data sets due to two vertical-sided prismatic bodies in a non-magnetic medium. For the field case, airborne magnetic anomalies originated from intrusive granitoids at the eastern part of the Biga Peninsula (NW Turkey) which is composed of various kinds of sedimentary, metamorphic and igneous rocks, have been inverted and interpreted. Since the granitoids are the outcropped rocks in the field, the estimations for the top depths of two prisms representing the magnetic bodies were excluded during inversion studies. Estimated bottom depths are in good agreement with the ones obtained by a different approach based on 3D modelling of pseudogravity anomalies. Accuracy of the estimated parameters from both cases has been also investigated via probability density functions. Based on the tests in the present study, it can be concluded that DE is a useful tool for the parameter estimation of source bodies using magnetic anomalies.

  20. Completely integrable models of nonlinear optics

    Indian Academy of Sciences (India)

    Andrey I Maimistov

    2001-11-01

    The models of the nonlinear optics in which solitons appeared are considered. These models are of paramount importance in studies of nonlinear wave phenomena. The classical examples of phenomena of this kind are the self-focusing, self-induced transparency and parametric interaction of three waves. At present there are a number of theories based on completely integrable systems of equations, which are, both, generations of the original known models and new ones. The modified Korteweg-de Vries equation, the nonlinear Schrödinger equation, the derivative nonlinear Schrödinger equation, Sine–Gordon equation, the reduced Maxwell–Bloch equation, Hirota equation, the principal chiral field equations, and the equations of massive Thirring model are some soliton equations, which are usually to be found in nonlinear optics theory.

  1. Scale-invariant nonlinear optics in gases

    CERN Document Server

    Heyl, C M; Miranda, M; Louisy, M; Kovacs, K; Tosa, V; Balogh, E; Varjú, K; L'Huillier, A; Couairon, A; Arnold, C L

    2015-01-01

    Nonlinear optical methods are becoming ubiquitous in many areas of modern photonics. They are, however, often limited to a certain range of input parameters, such as pulse energy and average power, since restrictions arise from, for example, parasitic nonlinear effects, damage problems and geometrical considerations. Here, we show that many nonlinear optics phenomena in gaseous media are scale-invariant if spatial coordinates, gas density and laser pulse energy are scaled appropriately. We develop a general scaling model for (3+1)-dimensional wave equations, demonstrating the invariant scaling of nonlinear pulse propagation in gases. Our model is numerically applied to high-order harmonic generation and filamentation as well as experimentally verified using the example of pulse post-compression via filamentation. Our results provide a simple recipe for up-or downscaling of nonlinear processes in gases with numerous applications in many areas of science.

  2. Fast, high-resolution 3D dosimetry utilizing a novel optical-CT scanner incorporating tertiary telecentric collimation

    OpenAIRE

    Sakhalkar, H. S.; Oldham, M

    2008-01-01

    This study introduces a charge coupled device (CCD) area detector based optical-computed tomography (optical-CT) scanner for comprehensive verification of radiation dose distributions recorded in nonscattering radiochromic dosimeters. Defining characteristics include: (i) a very fast scanning time of ~5 min to acquire a complete three-dimensional (3D) dataset, (ii) improved image formation through the use of custom telecentric optics, which ensures accurate projection images and minimizes art...

  3. A prototype fan-beam optical CT scanner for 3D dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Warren G.; Rudko, D. A.; Braam, Nicolas A.; Jirasek, Andrew [University of Victoria, Victoria, British Columbia V8P 5C2 (Canada); Wells, Derek M. [British Columbia Cancer Agency, Vancouver Island Centre, Victoria, British Columbia V8R 6V5 (Canada)

    2013-06-15

    Purpose: The objective of this work is to introduce a prototype fan-beam optical computed tomography scanner for three-dimensional (3D) radiation dosimetry. Methods: Two techniques of fan-beam creation were evaluated: a helium-neon laser (HeNe, {lambda} = 543 nm) with line-generating lens, and a laser diode module (LDM, {lambda} = 635 nm) with line-creating head module. Two physical collimator designs were assessed: a single-slot collimator and a multihole collimator. Optimal collimator depth was determined by observing the signal of a single photodiode with varying collimator depths. A method of extending the dynamic range of the system is presented. Two sample types were used for evaluations: nondosimetric absorbent solutions and irradiated polymer gel dosimeters, each housed in 1 liter cylindrical plastic flasks. Imaging protocol investigations were performed to address ring artefacts and image noise. Two image artefact removal techniques were performed in sinogram space. Collimator efficacy was evaluated by imaging highly opaque samples of scatter-based and absorption-based solutions. A noise-based flask registration technique was developed. Two protocols for gel manufacture were examined. Results: The LDM proved advantageous over the HeNe laser due to its reduced noise. Also, the LDM uses a wavelength more suitable for the PRESAGE{sup TM} dosimeter. Collimator depth of 1.5 cm was found to be an optimal balance between scatter rejection, signal strength, and manufacture ease. The multihole collimator is capable of maintaining accurate scatter-rejection to high levels of opacity with scatter-based solutions (T < 0.015%). Imaging protocol investigations support the need for preirradiation and postirradiation scanning to reduce reflection-based ring artefacts and to accommodate flask imperfections and gel inhomogeneities. Artefact removal techniques in sinogram space eliminate streaking artefacts and reduce ring artefacts of up to {approx}40% in magnitude. The

  4. Investigation of Optical Fibers for Nonlinear Optics.

    Science.gov (United States)

    1984-04-17

    Northwestern University, 1970. Experience Dr. Harrington has 13 years of research experi- ence in the area of optical properties of solids . Since joining...dynamics, and optical properties of solids . 34 34I ANTONIO C. PASTOR, Member of the Technical Staff, Optical Physics Department, Hughes Research

  5. Nonlinear Integrated Optical Waveguides in Chalcogenide Glasses

    Institute of Scientific and Technical Information of China (English)

    Yinlan; Ruan; Barry; Luther-Davies; Weitang; Li; Andrei; Rode; Marek; Samoc

    2003-01-01

    This paper reports on the study and measurement of the third order optical nonlinearity in bulk sulfide-based chalcogenide glasses; The fabrication process of the ultrafast laser deposited As-S-(Se)-based chalcogenide films and optical waveguides using two techniques: wet chemistry etching and plasma etching.

  6. Evaluation of hybrid polymers for high-precision manufacturing of 3D optical interconnects by two-photon absorption lithography

    Science.gov (United States)

    Schleunitz, A.; Klein, J. J.; Krupp, A.; Stender, B.; Houbertz, R.; Gruetzner, G.

    2017-02-01

    The fabrication of optical interconnects has been widely investigated for the generation of optical circuit boards. Twophoton absorption (TPA) lithography (or high-precision 3D printing) as an innovative production method for direct manufacture of individual 3D photonic structures gains more and more attention when optical polymers are employed. In this regard, we have evaluated novel ORMOCER-based hybrid polymers tailored for the manufacture of optical waveguides by means of high-precision 3D printing. In order to facilitate future industrial implementation, the processability was evaluated and the optical performance of embedded waveguides was assessed. The results illustrate that hybrid polymers are not only viable consumables for industrial manufacture of polymeric micro-optics using generic processes such as UV molding. They also are potential candidates to fabricate optical waveguide systems down to the chip level where TPA-based emerging manufacturing techniques are engaged. Hence, it is shown that hybrid polymers continue to meet the increasing expectations of dynamically growing markets of micro-optics and optical interconnects due to the flexibility of the employed polymer material concept.

  7. Forbidden second order optical nonlinearity of graphene

    CERN Document Server

    Cheng, J L; Sipe, J E

    2016-01-01

    We present a practical scheme to separate the contributions of the electric quadrupole-like and the magnetic dipole-like effects to the forbidden second order optical nonlinear response of graphene, and give analytic expressions for the second order optical conductivities, calculated from the independent particle approximation, with relaxation described in a phenomenological way. We predict strong second order nonlinear effects, including second harmonic generation, photon drag, and difference frequency generation. We discuss in detail the controllablity of these responses by tuning the chemical potential, where the interband optical transitions play a dominant role.

  8. Optical nonlinearities of small polarons in lithium niobate

    Science.gov (United States)

    Imlau, Mirco; Badorreck, Holger; Merschjann, Christoph

    2015-12-01

    An overview of optical nonlinearities of small bound polarons is given, which can occur in the congruently melting composition of LiNbO3. Such polarons decisively influence the linear and nonlinear optical performance of this material that is important for the field of optics and photonics. On the basis of an elementary phenomenological approach, the localization of carriers in a periodic lattice with intrinsic defects is introduced. It is applied to describe the binding energies of four electron and hole small polarons in LiNbO3: small free NbNb4 + polarons, small bound NbLi4 + polarons, small bound NbLi4 +:NbNb4 + bipolarons, and small bound O- hole polarons. For the understanding of their linear interaction with light, an optically induced transfer between nearest-neighboring polaronic sites is assumed. It reveals spectrally well separated optical absorption features in the visible and near-infrared spectral range, their small polaron peak energies and lineshapes. Nonlinear interaction of light is assigned to the optical formation of short-lived small polarons as a result of carrier excitation by means of band-to-band transitions. It is accompanied by the appearance of a transient absorption being spectrally constituted by the individual fingerprints of the small polarons involved. The relaxation dynamics of the transients is thermally activated and characterized phenomenologically by a stretched exponential behavior, according to incoherent 3D small polaron hopping between regular and defect sites of the crystal lattice. It is shown that the analysis of the dynamics is a useful tool for revealing the recombination processes between small polarons of different charge. Nonlinear interaction of small polarons with light furthermore results in changes of the index of refraction. Besides its causal relation to the transients via Kramers-Kronig relation, pronounced index changes may occur due to optically generated electric fields modulating the index of refraction

  9. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    . The combination of a small core size and zero-dispersion wavelength at the operating wavelength of widely available femtosecond Ti:sapphire lasers led to an extensive research in supercontinuum generation and other nonlinear effects in PCFs. It is crucial for the efficiency of many nonlinear mechanisms...... that the pump laser wavelength is close to the zero-dispersion wavelength and that the core size is small. Recently, work in fabricating PCFs from materials other than silica has intensified. One of the advantages of using alternative materials can be a higher inherent material nonlinearity, which...... to accurately obtain a small core size while maintaining small structural variations during fibre drawing. This talk will give a presentation of how the mPOFs are fabricated and the route to obtaining nonlinear effects in them....

  10. Mesoscale Engineering of Nanocomposite Nonlinear Optical Materials

    Energy Technology Data Exchange (ETDEWEB)

    Afonso, C.N.; Feldman, L.C.; Gonella, F.; Haglund, R.F.; Luepke, G.; Magruder, R.H.; Mazzoldi, P.; Osborne, D.H.; Solis, J.; Zuhr, R.A.

    1999-11-01

    Complex nonlinear optical materials comprising elemental, compound or alloy quantum dots embedded in appropriate dielectric or semiconducting hosts may be suitable for deployment in photonic devices. Ion implantation, ion exchange followed by ion implantation, and pulsed laser deposition have ail been used to synthesize these materials. However, the correlation between the parameters of energetic-beam synthesis and the nonlinear optical properties is still very rudimentary when one starts to ask what is happening at nanoscale dimensions. Systems integration of complex nonlinear optical materials requires that the mesoscale materials science be well understood within the context of device structures. We discuss the effects of beam energy and energy density on quantum-dot size and spatial distribution, thermal conductivity, quantum-dot composition, crystallinity and defects - and, in turn, on the third-order optical susceptibility of the composite material. Examples from recent work in our laboratories are used to illustrate these effects.

  11. Nonlinear dynamics in atom optics

    Energy Technology Data Exchange (ETDEWEB)

    Chen Wenyu; Dyrting, S.; Milburn, G.J. [Queensland Univ., St. Lucia, QLD (Australia). Dept. of Physics

    1996-12-31

    In this paper theoretical work on classical and quantum nonlinear dynamics of cold atoms is reported. The basic concepts in nonlinear dynamics are reviewed and then applied to the motion of atoms in time-dependent standing waves and to the atomic bouncer. The quantum dynamics for the cases of regular and chaotic classical dynamics is described. The effect of spontaneous emission and external noise is also discussed. 104 refs., 1 tab., 21 figs.

  12. A new technique of recognition for coded targets in optical 3D measurement

    Science.gov (United States)

    Guo, Changye; Cheng, Xiaosheng; Cui, Haihua; Dai, Ning; Weng, Jinping

    2014-11-01

    A new technique for coded targets recognition in optical 3D-measurement application is proposed in this paper. Traditionally, point cloud registration is based on homologous features, such as the curvature, which is time-consuming and not reliable. For this, we paste some coded targets onto the surface of the object to be measured to improve the optimum target location and accurate correspondence among multi-source images. Circular coded targets are used, and an algorithm to automatically detecting them is proposed. This algorithm extracts targets with intensive bimodal histogram features from complex background, and filters noise according to their size, shape and intensity. In addition, the coded targets' identification is conducted out by their ring codes. We affine them around the circle inversely, set foreground and background respectively as 1 and 0 to constitute a binary number, and finally shift one bit every time to calculate a decimal one of the binary number to determine a minimum decimal number as its code. In this 3Dmeasurement application, we build a mutual relationship between different viewpoints containing three or more coded targets with different codes. Experiments show that it is of efficiency to obtain global surface data of an object to be measured and is robust to the projection angles and noise.

  13. Close-range optical measurement of aircraft's 3D attitude and accuracy evaluation

    Institute of Scientific and Technical Information of China (English)

    Zhe Li; Zhenliang Ding; Feng Yuan

    2008-01-01

    A new screen-spot imaging method based on optical measurement is proposed, which is applicable to the close-range measurement of aircraft's three-dimensional (3D) attitude parameters. Laser tracker is used to finish the global calibrations of the high-speed cameras and the fixed screens on test site, as well as to establish media-coordinate-frames among various coordinate systems. The laser cooperation object mounted on the aircraft surface projects laser beams on the screens and the high-speed cameras syn-chronously record the light-spots' position changing with aircraft attitude. The recorded image sequences are used to compute the aircraft attitude parameters. Based on the matrix analysis, the error sources of the measurement accuracy are analyzed, and the maximum relative error of this mathematical model is estimated. The experimental result shows that this method effectively makes the change of aircraft position distinguishable, and the error of this method is no more than 3' while the rotation angles of three axes are within a certain range.

  14. 3D Curvelet-Based Segmentation and Quantification of Drusen in Optical Coherence Tomography Images

    Directory of Open Access Journals (Sweden)

    M. Esmaeili

    2017-01-01

    Full Text Available Spectral-Domain Optical Coherence Tomography (SD-OCT is a widely used interferometric diagnostic technique in ophthalmology that provides novel in vivo information of depth-resolved inner and outer retinal structures. This imaging modality can assist clinicians in monitoring the progression of Age-related Macular Degeneration (AMD by providing high-resolution visualization of drusen. Quantitative tools for assessing drusen volume that are indicative of AMD progression may lead to appropriate metrics for selecting treatment protocols. To address this need, a fully automated algorithm was developed to segment drusen area and volume from SD-OCT images. The proposed algorithm consists of three parts: (1 preprocessing, which includes creating binary mask and removing possible highly reflective posterior hyaloid that is used in accurate detection of inner segment/outer segment (IS/OS junction layer and Bruch’s membrane (BM retinal layers; (2 coarse segmentation, in which 3D curvelet transform and graph theory are employed to get the possible candidate drusenoid regions; (3 fine segmentation, in which morphological operators are used to remove falsely extracted elongated structures and get the refined segmentation results. The proposed method was evaluated in 20 publically available volumetric scans acquired by using Bioptigen spectral-domain ophthalmic imaging system. The average true positive and false positive volume fractions (TPVF and FPVF for the segmentation of drusenoid regions were found to be 89.15% ± 3.76 and 0.17% ± .18%, respectively.

  15. Nonlinear optics with stationary pulses of light

    OpenAIRE

    Andre, A.; Bajcsy, M.; Zibrov, A. S.; Lukin, M. D.

    2004-01-01

    We show that the recently demonstrated technique for generating stationary pulses of light [Nature {\\bf 426}, 638 (2003)] can be extended to localize optical pulses in all three spatial dimensions in a resonant atomic medium. This method can be used to dramatically enhance the nonlinear interaction between weak optical pulses. In particular, we show that an efficient Kerr-like interaction between two pulses can be implemented as a sequence of several purely linear optical processes. The resul...

  16. Nonlinear optical properties of metal nanoparticle composites for optical applications

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Y. E-mail: takeda.yoshihiko@nims.go.jp; Kishimoto, N

    2003-05-01

    Optical absorption and nonlinear optical response were investigated for nanoparticle composites in amorphous SiO{sub 2} fabricated by negative Ta ion implantation at 60 keV. X-ray photoelectron spectroscopy was used to identify Ta and the oxide formation in the matrix. Optical absorption clearly indicated a surface plasmon peak at 2.2 eV and the peak resulted from formation of nanoparticles embedded in the matrix. The measured absorption was compared with calculated ones, evaluated by Maxwell-Garnett theory. Nonlinear absorption was measured with a pump-probe method using a femtosecond laser system. The pumping laser transiently bleached the surface plasmon band and lead to the nonlinearity. The transient response recovered in several picoseconds and behaved in terms of electron dynamics in metallic nanoparticles. The Ta nanoparticle composite is one of the promising candidates for nonlinear optical materials with good thermal stability.

  17. Fast optical 3D form measurement of aspheres including determination of thickness and wedge and decenter errors

    Science.gov (United States)

    Stover, E.; Berger, G.; Wendel, M.; Petter, J.

    2015-10-01

    A method for non-contact 3D form testing of aspheric surfaces including determination of decenter and wedge errors and lens thickness is presented. The principle is based on the absolute measurement capability of multi-wavelength interferometry (MWLI). The approach produces high density 3D shape information and geometric parameters at high accuracy in short measurement times. The system allows inspection of aspheres without restrictions in terms of spherical departures, of segmented and discontinuous optics. The optics can be polished or ground and made of opaque or transparent materials.

  18. Femtosecond laser aided processing of optical sensor fibers for 3D medical navigation and tracking (FiberNavi)

    Science.gov (United States)

    Waltermann, Christian; Koch, Jan; Angelmahr, Martin; Schade, Wolfgang; Witte, Michael; Kohn, Nils; Wilhelm, Dirk; Schneider, Armin; Reiser, Silvano; Feußner, Hubertus

    2014-05-01

    A new concept for fiber-optical 3D shape sensing applying femtosecond laser technology for highprecision direct writing of Bragg gratings within the core and the cladding of single core standard telecom fibers is presented. This new technology enables a cost-efficient and real-time 3D shape sensing and navigation of medical catheters or endoscopes only by means of passive optical sensor elements. First prototypes showed the possibility to achieve absolute navigation accuracy of four mm per meter and have successfully been tested in clinical environment.

  19. Optical rogue waves and soliton turbulence in nonlinear fibre optics

    DEFF Research Database (Denmark)

    Genty, G.; Dudley, J. M.; de Sterke, C. M.

    2009-01-01

    We examine optical rogue wave generation in nonlinear fibre propagation in terms of soliton turbulence. We show that higher-order dispersion is sufficient to generate localized rogue soliton structures, and Raman scattering effects are not required.......We examine optical rogue wave generation in nonlinear fibre propagation in terms of soliton turbulence. We show that higher-order dispersion is sufficient to generate localized rogue soliton structures, and Raman scattering effects are not required....

  20. Interferometric and nonlinear-optical spectral-imaging techniques for outer space and live cells

    Science.gov (United States)

    Itoh, Kazuyoshi

    2015-12-01

    Multidimensional signals such as the spectral images allow us to have deeper insights into the natures of objects. In this paper the spectral imaging techniques that are based on optical interferometry and nonlinear optics are presented. The interferometric imaging technique is based on the unified theory of Van Cittert-Zernike and Wiener-Khintchine theorems and allows us to retrieve a spectral image of an object in the far zone from the 3D spatial coherence function. The retrieval principle is explained using a very simple object. The promising applications to space interferometers for astronomy that are currently in progress will also be briefly touched on. An interesting extension of interferometric spectral imaging is a 3D and spectral imaging technique that records 4D information of objects where the 3D and spectral information is retrieved from the cross-spectral density function of optical field. The 3D imaging is realized via the numerical inverse propagation of the cross-spectral density. A few techniques suggested recently are introduced. The nonlinear optical technique that utilizes stimulated Raman scattering (SRS) for spectral imaging of biomedical targets is presented lastly. The strong signals of SRS permit us to get vibrational information of molecules in the live cell or tissue in real time. The vibrational information of unstained or unlabeled molecules is crucial especially for medical applications. The 3D information due to the optical nonlinearity is also the attractive feature of SRS spectral microscopy.

  1. Nonlinear optical properties of semiconductor nanocrystals

    Science.gov (United States)

    Ricard, Gianpiero Banfi Vittorio Degiorgio Daniel

    1998-05-01

    This review is devoted to the description of recent experimental results concerning the nonlinear optical properties of semiconductor-doped glasses SDGs with particular emphasis on the regime in which the energy of the incident photon is smaller than the energy gap. A considerable theoretical and experimental effort has been devoted in the last 10years to the fundamental aspects of quantumconfined structures, which have properties somewhat intermediate between the bulk crystals and atoms or molecules. From this point of view, SDGs represent an easily available test system, and optical techniques have been a major diagnostic tool. Luminescence and absorption spectroscopy were extensively used to characterize the electronic states. The experiments aimed at the measurement of the real and imaginary parts of the third-order optical susceptibility of SDGs below the bandgap are described in some detail, and the results obtained with different techniques are compared. Besides the intrinsic fast nonlinearity due to bound electrons, SDGs may present a larger but much slower nonlinearity due to the free carriers generated by two-photon absorption. This implies that experiments have to be properly designed for separation of the two effects. In this article we stress the importance of a detailed structural characterization of the samples. Knowledge of the volume fraction occupied by the nanocrystals is necessary in order to derive from the experimental data the intrinsic nonlinearity and to compare it with the bulk nonlinearity. We discuss recent experiments in which the dependence of the intrinsic nonlinearity on the crystal size is derived by performing, on the samples, measurements of the real part and imaginary part of the nonlinear optical susceptibility and measurements of crystal size and volume fraction. Structural characterization is of interest also for a better understanding of the physical processes underlying the growth of crystallites in SDGs. The average size of

  2. Nonlinear optical model for strip plasmonic waveguides

    DEFF Research Database (Denmark)

    Lysenko, Oleg; Bache, Morten; Lavrinenko, Andrei

    2016-01-01

    This paper presents a theoretical model of nonlinear optical properties for strip plasmonic waveguides. The particular waveguides geometry that we investigate contains a gold core, adhesion layers, and silicon dioxide cladding. It is shown that the third-order susceptibility of the gold core...... significantly depends on the layer thickness and has the dominant contribution to the effective third-order susceptibility of the long-range plasmon polariton mode. This results in two nonlinear optical effects in plasmonic waveguides, which we experimentally observed and reported in [Opt. Lett. 41, 317 (2016......)]. The first effect is the nonlinear power saturation of the plasmonic mode, and the second effect is the spectral broadening of the plasmonic mode. Both nonlinear plasmonic effects can be used for practical applications and their appropriate model will be important for further developments in communication...

  3. Accuracy of optical scanning methods of the Cerec®3D system in the process of making ceramic inlays

    Directory of Open Access Journals (Sweden)

    Trifković Branka

    2010-01-01

    Full Text Available Background/Aim. One of the results of many years of Cerec® 3D CAD/CAM system technological development is implementation of one intraoral and two extraoral optical scanning methods which, depending on the current indications, are applied in making fixed restorations. The aim of this study was to determine the degree of precision of optical scanning methods by the use of the Cerec®3D CAD/CAM system in the process of making ceramic inlays. Methods. The study was conducted in three experimental groups of inlays prepared using the procedure of three methods of scanning Cerec ®3D system. Ceramic inlays made by conventional methodology were the control group. The accuracy of optical scanning methods of the Cerec®3D system computer aided designcomputer aided manufacturing (CAD/CAM was indirectly examined by measuring a marginal gap size between inlays and demarcation preparation by scanning electron microscope (SEM. Results. The results of the study showed a difference in the accuracy of the existing methods of scanning dental CAD/CAM systems. The highest level of accuracy was achieved by the extraoral optical superficial scanning technique. The value of marginal gap size inlays made with the technique of extraoral optical superficial scanning was 32.97 ± 13.17 μ. Techniques of intraoral optical superficial and extraoral point laser scanning showed a lower level of accuracy (40.29 ± 21.46 μ for inlays of intraoral optical superficial scanning and 99.67 ± 37.25 μ for inlays of extraoral point laser scanning. Conclusion. Optical scanning methods in dental CAM/CAM technologies are precise methods of digitizing the spatial models; application of extraoral optical scanning methods provides the hightest precision.

  4. Constrained non-linear optimization in 3D reflexion tomography; Problemes d'optimisation non-lineaire avec contraintes en tomographie de reflexion 3D

    Energy Technology Data Exchange (ETDEWEB)

    Delbos, F.

    2004-11-01

    Reflexion tomography allows the determination of a subsurface velocity model from the travel times of seismic waves. The introduction of a priori information in this inverse problem can lead to the resolution of a constrained non-linear least-squares problem. The goal of the thesis is to improve the resolution techniques of this optimization problem, whose main difficulties are its ill-conditioning, its large scale and an expensive cost function in terms of CPU time. Thanks to a detailed study of the problem and to numerous numerical experiments, we justify the use of a sequential quadratic programming method, in which the tangential quadratic programs are solved by an original augmented Lagrangian method. We show the global linear convergence of the latter. The efficiency and robustness of the approach are demonstrated on several synthetic examples and on two real data cases. (author)

  5. Rotational Doppler effect in nonlinear optics

    Science.gov (United States)

    Li, Guixin; Zentgraf, Thomas; Zhang, Shuang

    2016-08-01

    The translational Doppler effect of electromagnetic and sound waves has been successfully applied in measurements of the speed and direction of vehicles, astronomical objects and blood flow in human bodies, and for the Global Positioning System. The Doppler effect plays a key role for some important quantum phenomena such as the broadened emission spectra of atoms and has benefited cooling and trapping of atoms with laser light. Despite numerous successful applications of the translational Doppler effect, it fails to measure the rotation frequency of a spinning object when the probing wave propagates along its rotation axis. This constraint was circumvented by deploying the angular momentum of electromagnetic waves--the so-called rotational Doppler effect. Here, we report on the demonstration of rotational Doppler shift in nonlinear optics. The Doppler frequency shift is determined for the second harmonic generation of a circularly polarized beam passing through a spinning nonlinear optical crystal with three-fold rotational symmetry. We find that the second harmonic generation signal with circular polarization opposite to that of the fundamental beam experiences a Doppler shift of three times the rotation frequency of the optical crystal. This demonstration is of fundamental significance in nonlinear optics, as it provides us with insight into the interaction of light with moving media in the nonlinear optical regime.

  6. Analysis of 3D-printed metal for rapid-prototyped reflective terahertz optics

    Science.gov (United States)

    Headland, Daniel; Withayachumnankul, Withawat; Webb, Michael; Ebendorff-Heidepriem, Heike; Luiten, Andre; Abbott, Derek

    2016-07-01

    We explore the potential of 3D metal printing to realize complex conductive terahertz devices. Factors impacting performance such as printing resolution, surface roughness, oxidation, and material loss are investigated via analytical, numerical, and experimental approaches. The high degree of control offered by a 3D-printed topology is exploited to realize a zone plate operating at 530 GHz. Reflection efficiency at this frequency is found to be over 90%. The high-performance of this preliminary device suggest that 3D metal printing can play a strong role in guided-wave and general beam control devices in the terahertz range.

  7. Analysis of 3D-printed metal for rapid-prototyped reflective terahertz optics

    CERN Document Server

    Headland, Daniel; Webb, Michael; Ebendorff-Heidepriem, Heike; Luiten, Andre; Abbott, Derek

    2016-01-01

    We explore the potential of 3D metal printing to realize complex conductive terahertz devices. Factors impacting performance such as printing resolution, surface roughness, oxidation, and material loss are investigated via analytical, numerical, and experimental approaches. The high degree of control offered by a 3D-printed topology is exploited to realize a zone plate operating at 530 GHz. Reflection efficiency at this frequency is found to be over 90%. The high-performance of this preliminary device suggest that 3D metal printing can play a strong role in guided-wave and general beam control devices in the terahertz range.

  8. Characterization of 3D printing output using an optical sensing system

    Science.gov (United States)

    Straub, Jeremy

    2015-05-01

    This paper presents the experimental design and initial testing of a system to characterize the progress and performance of a 3D printer. The system is based on five Raspberry Pi single-board computers. It collects images of the 3D printed object, which are compared to an ideal model. The system, while suitable for printers of all sizes, can potentially be produced at a sufficiently low cost to allow its incorporation into consumer-grade printers. The efficacy and accuracy of this system is presented and discussed. The paper concludes with a discussion of the benefits of being able to characterize 3D printer performance.

  9. Tunable nanowire nonlinear optical probe

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Yuri; Pauzauskie, Peter J.; Radenovic, Aleksandra; Onorato, Robert M.; Saykally, Richard J.; Liphardt, Jan; Yang, Peidong

    2008-02-18

    One crucial challenge for subwavelength optics has been thedevelopment of a tunable source of coherent laser radiation for use inthe physical, information, and biological sciences that is stable at roomtemperature and physiological conditions. Current advanced near-fieldimaging techniques using fiber-optic scattering probes1,2 have alreadyachieved spatial resolution down to the 20-nm range. Recently reportedfar-field approaches for optical microscopy, including stimulatedemission depletion (STED)3, structured illumination4, and photoactivatedlocalization microscopy (PALM)5, have also enabled impressive,theoretically-unlimited spatial resolution of fluorescent biomolecularcomplexes. Previous work with laser tweezers6-8 has suggested the promiseof using optical traps to create novel spatial probes and sensors.Inorganic nanowires have diameters substantially below the wavelength ofvisible light and have unique electronic and optical properties9,10 thatmake them prime candidates for subwavelength laser and imagingtechnology. Here we report the development of an electrode-free,continuously-tunable coherent visible light source compatible withphysiological environments, from individual potassium niobate (KNbO3)nanowires. These wires exhibit efficient second harmonic generation(SHG), and act as frequency converters, allowing the local synthesis of awide range of colors via sum and difference frequency generation (SFG,DFG). We use this tunable nanometric light source to implement a novelform of subwavelength microscopy, in which an infrared (IR) laser is usedto optically trap and scan a nanowire over a sample, suggesting a widerange of potential applications in physics, chemistry, materials science,and biology.

  10. Towards multimodal nonlinear optical tomography - experimental methodology

    Science.gov (United States)

    Vogler, N.; Medyukhina, A.; Latka, I.; Kemper, S.; Böhm, M.; Dietzek, B.; Popp, J.

    2011-08-01

    All-optical microspectroscopic and tomographic tools reveal great potential for clinical dermatologic diagnostics, i.e., investigation of human skin and skin diseases. While optical-coherence tomography has been complemented by two-photon fluorescence tomography and second-harmonic generation tomography, a joint study of various nonlinear optical microspectroscopies, i.e., application of the recently developed multimodal imaging approach, to sizable human-tissue samples has not been evaluated up to now. Here, we present such multimodal approach combining different nonlinear optical contrast mechanisms for imaging, namely two-photon excited fluorescence (TPF), second-harmonic generation (SHG), and coherent anti-Stokes Raman scattering (CARS) into a joint microscopic experiment. We show the potential of imaging large skin areas and discuss the information obtained in a case study comparing normal skin and keloid tissue.

  11. Progress in understanding disruptions triggered by massive gas injection via 3D non-linear MHD modelling with JOREK

    Science.gov (United States)

    Nardon, E.; Fil, A.; Hoelzl, M.; Huijsmans, G.; contributors, JET

    2017-01-01

    3D non-linear MHD simulations of a D 2 massive gas injection (MGI) triggered disruption in JET with the JOREK code provide results which are qualitatively consistent with experimental observations and shed light on the physics at play. In particular, it is observed that the gas destabilizes a large m/n  =  2/1 tearing mode, with the island O-point coinciding with the gas deposition region, by enhancing the plasma resistivity via cooling. When the 2/1 island gets so large that its inner side reaches the q  =  3/2 surface, a 3/2 tearing mode grows. Simulations suggest that this is due to a steepening of the current profile right inside q  =  3/2. Magnetic field stochastization over a large fraction of the minor radius as well as the growth of higher n modes ensue rapidly, leading to the thermal quench (TQ). The role of the 1/1 internal kink mode is discussed. An I p spike at the TQ is obtained in the simulations but with a smaller amplitude than in the experiment. Possible reasons are discussed.

  12. Quantum nonlinear optics: nonlinear optics meets the quantum world (Conference Presentation)

    Science.gov (United States)

    Boyd, Robert W.

    2016-02-01

    This presentation first reviews the historical development of the field of nonlinear optics, starting from its inception in 1961. It then reviews some of its more recent developments, including especially how nonlinear optics has become a crucial tool for the developing field of quantum technologies. Fundamental quantum processes enabled by nonlinear optics, such as the creation of squeezed and entangled light states, are reviewed. We then illustrate these concepts by means of specific applications, such as the development of secure communication systems based on the quantum states of light.

  13. 3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head

    Science.gov (United States)

    Lee, Kyungmoo; Abràmoff, Michael D.; Niemeijer, Meindert; Garvin, Mona K.; Sonka, Milan

    2010-03-01

    Segmentation of retinal blood vessels can provide important information for detecting and tracking retinal vascular diseases including diabetic retinopathy, arterial hypertension, arteriosclerosis and retinopathy of prematurity (ROP). Many studies on 2-D segmentation of retinal blood vessels from a variety of medical images have been performed. However, 3-D segmentation of retinal blood vessels from spectral-domain optical coherence tomography (OCT) volumes, which is capable of providing geometrically accurate vessel models, to the best of our knowledge, has not been previously studied. The purpose of this study is to develop and evaluate a method that can automatically detect 3-D retinal blood vessels from spectral-domain OCT scans centered on the optic nerve head (ONH). The proposed method utilized a fast multiscale 3-D graph search to segment retinal surfaces as well as a triangular mesh-based 3-D graph search to detect retinal blood vessels. An experiment on 30 ONH-centered OCT scans (15 right eye scans and 15 left eye scans) from 15 subjects was performed, and the mean unsigned error in 3-D of the computer segmentations compared with the independent standard obtained from a retinal specialist was 3.4 +/- 2.5 voxels (0.10 +/- 0.07 mm).

  14. Optical low-cost and portable arrangement for full field 3D displacement measurement using a single camera

    Science.gov (United States)

    López-Alba, E.; Felipe-Sesé, L.; Schmeer, S.; Díaz, F. A.

    2016-11-01

    In the current paper, an optical low-cost system for 3D displacement measurement based on a single camera and 3D digital image correlation is presented. The conventional 3D-DIC set-up based on a two-synchronized-cameras system is compared with a proposed pseudo-stereo portable system that employs a mirror system integrated in a device for a straightforward application achieving a novel handle and flexible device for its use in many scenarios. The proposed optical system splits the image by the camera into two stereo images of the object. In order to validate this new approach and quantify its uncertainty compared to traditional 3D-DIC systems, solid rigid in and out-of-plane displacements experiments have been performed and analyzed. The differences between both systems have been studied employing an image decomposition technique which performs a full image comparison. Therefore, results of all field of view are compared with those using a stereoscopy system and 3D-DIC, discussing the accurate results obtained with the proposed device not having influence any distortion or aberration produced by the mirrors. Finally, the adaptability of the proposed system and its accuracy has been tested performing quasi-static and dynamic experiments using a silicon specimen under high deformation. Results have been compared and validated with those obtained from a conventional stereoscopy system showing an excellent level of agreement.

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

    Science.gov (United States)

    2017-03-01

    acrylonitrile butadiene styrene (ABS), and polylactic acid (PLA). All three materials are common, low-cost, 3-D printed materials. Pictures of... Lewis , R. A., “3D Printed Terahertz Diffraction Gratings and Lenses,” Journal of Infrared Millimeter and Terahertz Waves, Volume 36, pp. 72-80...Impact polystyrene mm millimeters ns nanosecond PLA polylactic acid pp p-polarized R Reflection ss s-polarized T Transmission THz

  16. A 3D Optical Surface Profilometer Using a Dual-Frequency Liquid Crystal-Based Dynamic Fringe Pattern Generator

    Directory of Open Access Journals (Sweden)

    Kyung-Il Joo

    2016-10-01

    Full Text Available We propose a liquid crystal (LC-based 3D optical surface profilometer that can utilize multiple fringe patterns to extract an enhanced 3D surface depth profile. To avoid the optical phase ambiguity and enhance the 3D depth extraction, 16 interference patterns were generated by the LC-based dynamic fringe pattern generator (DFPG using four-step phase shifting and four-step spatial frequency varying schemes. The DFPG had one common slit with an electrically controllable birefringence (ECB LC mode and four switching slits with a twisted nematic LC mode. The spatial frequency of the projected fringe pattern could be controlled by selecting one of the switching slits. In addition, moving fringe patterns were obtainable by applying voltages to the ECB LC layer, which varied the phase difference between the common and the selected switching slits. Notably, the DFPG switching time required to project 16 fringe patterns was minimized by utilizing the dual-frequency modulation of the driving waveform to switch the LC layers. We calculated the phase modulation of the DFPG and reconstructed the depth profile of 3D objects using a discrete Fourier transform method and geometric optical parameters.

  17. Recent Issues on Nonlinear Effects in Optical Fibers

    Institute of Scientific and Technical Information of China (English)

    Takashi; Inoue; Osamu; Aso; Shu; Namiki

    2003-01-01

    This talk will discuss the types of optical signal degradation due to fiber nonlinearity and review recently invented fibers for suppressing the effects. It also introduces efficiency of highly nonlinear fibers and their applications to nonlinear signal processing.

  18. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    is potentially the case for microstructured polymer optical fibres (mPOFs). Another advantage is that polymer materials have a higher biocompatibility than silica, meaning that it is easier to bond certain types of biosensor materials to a polymer surface than to silica. As with silica PCFs, it is difficult...

  19. FreeCAD visualization of realistic 3D physical optics beams within a CAD system-model

    Science.gov (United States)

    Gayer, D.; O'Sullivan, C.; Scully, S.; Burke, D.; Brossard, J.; Chapron, C.

    2016-07-01

    The facility to realise the shape and extent of optical beams within a telescope or beamcombiner can aid greatly in the design and layout of optical elements within the system. It can also greatly facilitate communication between the optical design team and other teams working on the mechanical design of an instrument. Beyond the realm where raytracing is applicable however, it becomes much more difficult to realise accurate 3D beams which incorporate diffraction effects. It then is another issue to incorporate this into a CAD model of the system. A novel method is proposed which has been used to aid with the design of an optical beam combiner for the QUBIC (Q and U Bolometric Interferometer for Cosmology) 1 experiment operating at 150 GHz and 220 GHz. The method combines calculation work in GRASP 2, a commercial physical optics modelling tool from TICRA, geometrical work in Mathematica, and post processing in MATLAB. Finally, the Python console of the open source package FreeCAD3 is exploited to realise the 3D beams in a complete CAD system-model of the QUBIC optical beam combiner. This paper details and explains the work carried out to reach the goal and presents some graphics of the outcome. 3D representations of beams from some back-to-back input horns of the QUBIC instrument are shown within the CAD model. Beams of the -3dB and -13dB contour envelope are shown as well as envelopes enclosing 80% and 95% of the power of the beam. The ability to see these beams in situ with all the other elements of the combiner such as mirrors, cold stop, beam splitter and cryostat widows etc. greatly simplified the design for these elements and facilitated communication of element dimension and location between different subgroups within the QUBIC group.

  20. Localized Turing patterns in nonlinear optical cavities

    Science.gov (United States)

    Kozyreff, G.

    2012-05-01

    The subcritical Turing instability is studied in two classes of models for laser-driven nonlinear optical cavities. In the first class of models, the nonlinearity is purely absorptive, with arbitrary intensity-dependent losses. In the second class, the refractive index is real and is an arbitrary function of the intracavity intensity. Through a weakly nonlinear analysis, a Ginzburg-Landau equation with quintic nonlinearity is derived. Thus, the Maxwell curve, which marks the existence of localized patterns in parameter space, is determined. In the particular case of the Lugiato-Lefever model, the analysis is continued to seventh order, yielding a refined formula for the Maxwell curve and the theoretical curve is compared with recent numerical simulation by Gomila et al. [D. Gomila, A. Scroggie, W. Firth, Bifurcation structure of dissipative solitons, Physica D 227 (2007) 70-77.

  1. Infiltrated microstructured fibers as tunable and nonlinear optical devices

    DEFF Research Database (Denmark)

    Rosberg, Christian Romer; Bennet, Francis; Neshev, Dragomir N.;

    We study the light guiding properties of microstructured optical fibers infiltrated with nonlinear liquids and demonstrate their applicability for spatial beam control in novel type tunable and nonlinear optical devices....

  2. Laser and nonlinear optical materials: SPIE volume 681

    Energy Technology Data Exchange (ETDEWEB)

    De Shazer, L.G.

    1987-01-01

    This book contains papers arranged under the following session headings: Nonlinear optical crystals; Laser host crystals; Electro-optic and magneto-optic materials; and Characterization of optical materials.

  3. Nonlinear compression of optical solitons

    Indian Academy of Sciences (India)

    M N Vinoj; V C Kuriakose

    2001-11-01

    In this paper, we consider nonlinear Schrödinger (NLS) equations, both in the anomalous and normal dispersive regimes, which govern the propagation of a single field in a fiber medium with phase modulation and fibre gain (or loss). The integrability conditions are arrived from linear eigen value problem. The variable transformations which connect the integrable form of modified NLS equations are presented. We succeed in Hirota bilinearzing the equations and on solving, exact bright and dark soliton solutions are obtained. From the results, we show that the soliton is alive, i.e. pulse area can be conserved by the inclusion of gain (or loss) and phase modulation effects.

  4. 3D modelling of non-linear visco-elasto-plastic crustal and lithospheric processes using LaMEM

    Science.gov (United States)

    Popov, Anton; Kaus, Boris

    2016-04-01

    LaMEM (Lithosphere and Mantle Evolution Model) is a three-dimensional thermo-mechanical numerical code to simulate crustal and lithospheric deformation. The code is based on a staggered finite difference (FDSTAG) discretization in space, which is a stable and very efficient technique to solve the (nearly) incompressible Stokes equations that does not suffer from spurious pressure modes or artificial compressibility (a typical feature of low-order finite element techniques). Higher order finite element methods are more accurate than FDSTAG methods under idealized test cases where the jump in viscosity is exactly aligned with the boundaries of the elements. Yet, geodynamically more realistic cases involve evolving subduction zones, nonlinear rheologies or localized plastic shear bands. In these cases, the viscosity pattern evolves spontaneously during a simulation or even during nonlinear iterations, and the advantages of higher order methods disappear and they all converge with approximately first order accuracy, similar to that of FDSTAG [1]. Yet, since FDSTAG methods have considerably less degrees of freedom than quadratic finite element methods, they require about an order of magnitude less memory for the same number of nodes in 3D which also implies that every matrix-vector multiplication is significantly faster. LaMEM is build on top of the PETSc library and uses the particle-in-cell technique to track material properties, history variables which makes it straightforward to incorporate effects like phase changes or chemistry. An internal free surface is present, together with (simple) erosion and sedimentation processes, and a number of methods are available to import complex geometries into the code (e.g, http://geomio.bitbucket.org). Customized Galerkin coupled geometric multigrid preconditioners are implemented which resulted in a good parallel scalability of the code (we have tested LaMEM on 458'752 cores [2]). Yet, the drawback of using FDSTAG

  5. NONLINEAR OPTICS: Nonlinear optical processes in planar waveguides and excitation of surface polaritons

    Science.gov (United States)

    Yashkir, O. V.; Yashkir, Yu N.

    1987-11-01

    An investigation is made of nonlinear optical interaction of light propagating in a planar waveguide with surface polaritons. Reduced wave equations for the amplitudes of the waveguide modes and surface polaritons are used to study the characteristics of generation of surface polaritons of difference frequency, parametric frequency up-conversion of the polaritons, and stimulated Raman scattering by the polaritons. An analysis is made of the characteristic properties of the investigated nonlinear optical processes.

  6. Investigations into the feasibility of optical-CT 3D dosimetry with minimal use of refractively matched fluids

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, Kelsey; Miles, Devin [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 (United States); Rankine, Leith [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Oldham, Mark, E-mail: mark.oldham@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2015-05-15

    Purpose: In optical-CT, the use of a refractively matched polyurethane solid-tank in place of a fluid bath has the potential to greatly increase practical convenience, reduce cost, and possibly improve the efficacy of flood corrections. This work investigates the feasibility of solid-tank optical-CT imaging for 3D dosimetry through computer simulation. Methods: A MATLAB ray-tracing simulation platform, ScanSim, was used to model a parallel-source telecentric optical-CT imaging system through a polyurethane solid-tank containing a central cylindrical hollow into which PRESAGE radiochromic dosimeters can be placed. A small amount of fluid fills the 1–5 mm gap between the dosimeter and the walls of the tank. The use of the solid-tank reduces the required amount of fluid by approximately 97%. To characterize the efficacy of solid-tank, optical-CT scanning simulations investigated sensitivity to refractive index (RI) mismatches between dosimeter, solid-tank, and fluid, for a variety of dosimeter (RI = 1.5–1.47) and fluid (RI = 1.55–1.0) combinations. Efficacy was evaluated through the usable radius (r{sub u}) metric, defined as the fraction of the radius of the dosimeter where measured dose is predicted to be within 2% of the ground truth entered into the simulation. Additional simulations examined the effect of increasing gap size (1–5 mm) between the dosimeter and solid-tank well. The effects of changing the lens tolerance (0.5°–5.0°) were also investigated. Results: As the RI mismatch between the dosimeter and solid-tank increased from 0 to 0.02, the usable radius decreased from 97.6% to 50.2%. The optimal fluid RI decreased nonlinearly from 1.5 to 1.34 as the mismatch increased and was up to 9% lower than the tank. Media mismatches between the dosimeter and solid-tank also exacerbate the effects of changing the gap size, with no easily quantifiable relationship with usable radius. Generally, the optimal fluid RI value increases as gap size increases and

  7. Implementing a Matrix-free Analytical Jacobian to Handle Nonlinearities in Models of 3D Lithospheric Deformation

    Science.gov (United States)

    Kaus, B.; Popov, A.

    2015-12-01

    The analytical expression for the Jacobian is a key component to achieve fast and robust convergence of the nonlinear Newton-Raphson iterative solver. Accomplishing this task in practice often requires a significant algebraic effort. Therefore it is quite common to use a cheap alternative instead, for example by approximating the Jacobian with a finite difference estimation. Despite its simplicity it is a relatively fragile and unreliable technique that is sensitive to the scaling of the residual and unknowns, as well as to the perturbation parameter selection. Unfortunately no universal rule can be applied to provide both a robust scaling and a perturbation. The approach we use here is to derive the analytical Jacobian for the coupled set of momentum, mass, and energy conservation equations together with the elasto-visco-plastic rheology and a marker in cell/staggered finite difference method. The software project LaMEM (Lithosphere and Mantle Evolution Model) is primarily developed for the thermo-mechanically coupled modeling of the 3D lithospheric deformation. The code is based on a staggered grid finite difference discretization in space, and uses customized scalable solvers form PETSc library to efficiently run on the massively parallel machines (such as IBM Blue Gene/Q). Currently LaMEM relies on the Jacobian-Free Newton-Krylov (JFNK) nonlinear solver, which approximates the Jacobian-vector product using a simple finite difference formula. This approach never requires an assembled Jacobian matrix and uses only the residual computation routine. We use an approximate Jacobian (Picard) matrix to precondition the Krylov solver with the Galerkin geometric multigrid. Because of the inherent problems of the finite difference Jacobian estimation, this approach doesn't always result in stable convergence. In this work we present and discuss a matrix-free technique in which the Jacobian-vector product is replaced by analytically-derived expressions and compare results

  8. Efficient 3D nonlinear warping of computed tomography: two high-performance implementations using OpenGL

    Science.gov (United States)

    Levin, David; Dey, Damini; Slomka, Piotr

    2005-04-01

    We have implemented two hardware accelerated Thin Plate Spline (TPS) warping algorithms. The first algorithm is a hardware-software approach (HW-TPS) that uses OpenGL Vertex Shaders to perform a grid warp. The second is a Graphics Processor based approach (GPU-TPS) that uses the OpenGL Shading Language to perform all warping calculations on the GPU. Comparison with a software TPS algorithm was used to gauge the speed and quality of both hardware algorithms. Quality was analyzed visually and using the Sum of Absolute Difference (SAD) similarity metric. Warping was performed using 92 user-defined displacement vectors for 512x512x173 serial lung CT studies, matching normal-breathing and deep-inspiration scans. On a Xeon 2.2 Ghz machine with an ATI Radeon 9800XT GPU the GPU-TPS required 26.1 seconds to perform a per-voxel warp compared to 148.2 seconds for the software algorithm. The HW-TPS needed 1.63 seconds to warp the same study while the GPU-TPS required 1.94 seconds and the software grid transform required 22.8 seconds. The SAD values calculated between the outputs of each algorithm and the target CT volume were 15.2%, 15.4% and 15.5% for the HW-TPS, GPU-TPS and both software algorithms respectively. The computing power of ubiquitous 3D graphics cards can be exploited in medical image processing to provide order of magnitude acceleration of nonlinear warping algorithms without sacrificing output quality.

  9. Generating multi-GeV electron bunches using single stage laser wakefield acceleration in a 3D nonlinear regime

    Directory of Open Access Journals (Sweden)

    W. Lu

    2007-06-01

    Full Text Available The extraordinary ability of space-charge waves in plasmas to accelerate charged particles at gradients that are orders of magnitude greater than in current accelerators has been well documented. We develop a phenomenological framework for laser wakefield acceleration (LWFA in the 3D nonlinear regime, in which the plasma electrons are expelled by the radiation pressure of a short pulse laser, leading to nearly complete blowout. Our theory provides a recipe for designing a LWFA for given laser and plasma parameters and estimates the number and the energy of the accelerated electrons whether self-injected or externally injected. These formulas apply for self-guided as well as externally guided pulses (e.g. by plasma channels. We demonstrate our results by presenting a sample particle-in-cell (PIC simulation of a 30   fs, 200 TW laser interacting with a 0.75 cm long plasma with density 1.5×10^{18}  cm^{-3} to produce an ultrashort (10 fs monoenergetic bunch of self-injected electrons at 1.5 GeV with 0.3 nC of charge. For future higher-energy accelerator applications, we propose a parameter space, which is distinct from that described by Gordienko and Pukhov [Phys. Plasmas 12, 043109 (2005PHPAEN1070-664X10.1063/1.1884126] in that it involves lower plasma densities and wider spot sizes while keeping the intensity relatively constant. We find that this helps increase the output electron beam energy while keeping the efficiency high.

  10. Anisotropic and nonlinear optical waveguides

    CERN Document Server

    Someda, CG

    1992-01-01

    Dielectric optical waveguides have been investigated for more than two decades. In the last ten years they have had the unique position of being simultaneously the backbone of a very practical and fully developed technology, as well as an extremely exciting area of basic, forefront research. Existing waveguides can be divided into two sets: one consisting of waveguides which are already in practical use, and the second of those which are still at the laboratory stage of their evolution. This book is divided into two separate parts: the first dealing with anisotropic waveguides, an

  11. Extreme nonlinear optics and laser damage

    Science.gov (United States)

    Maldutis, Evaldas

    2010-11-01

    The study of laser induced damage threshold caused by series of identical laser pulses (LID-T-N) on gamma radiation resistant glasses and their analogs is performed applying know-how ultra stable laser radiation. The presented results and analysis of earlier received results show that nonlinear optical phenomena in extreme conditions of interaction are different from the traditional nonlinear optical processes, because they depend not only on intensity of electromagnetic field of laser radiation, but also on the pulse number in series of identical laser pulses. This range of laser intensities is not wide; it is different for each material and determines the range of Extreme Nonlinear Optics. The dependence of LID-T-N on pulse number N for different kinds of high quality transparent glasses was observed. The study of dynamics of these processes (i.e. the study of dependence on N) at different intensities in series of incident laser pulses provides new information about properties of the materials useful for studying laser damage fundamentals and their application. The expectation that gamma radiation resistant glasses could give useful information for technology of resistant optics for high power lasers has not proved. The received results well correspond with the earlier proposed model of laser damage.

  12. Rigorous theory of molecular orientational nonlinear optics

    Directory of Open Access Journals (Sweden)

    Chong Hoon Kwak

    2015-01-01

    Full Text Available Classical statistical mechanics of the molecular optics theory proposed by Buckingham [A. D. Buckingham and J. A. Pople, Proc. Phys. Soc. A 68, 905 (1955] has been extended to describe the field induced molecular orientational polarization effects on nonlinear optics. In this paper, we present the generalized molecular orientational nonlinear optical processes (MONLO through the calculation of the classical orientational averaging using the Boltzmann type time-averaged orientational interaction energy in the randomly oriented molecular system under the influence of applied electric fields. The focal points of the calculation are (1 the derivation of rigorous tensorial components of the effective molecular hyperpolarizabilities, (2 the molecular orientational polarizations and the electronic polarizations including the well-known third-order dc polarization, dc electric field induced Kerr effect (dc Kerr effect, optical Kerr effect (OKE, dc electric field induced second harmonic generation (EFISH, degenerate four wave mixing (DFWM and third harmonic generation (THG. We also present some of the new predictive MONLO processes. For second-order MONLO, second-order optical rectification (SOR, Pockels effect and difference frequency generation (DFG are described in terms of the anisotropic coefficients of first hyperpolarizability. And, for third-order MONLO, third-order optical rectification (TOR, dc electric field induced difference frequency generation (EFIDFG and pump-probe transmission are presented.

  13. Optical sensing technologies for the generation of reality-based 3D models of Cultural Heritage artifacts

    OpenAIRE

    2012-01-01

    The central theme of the thesis is the use of triangulation laser scanning and other optical three-dimensional surveying systems for the realization of 3D models of objects of historical and artistic interest - sculptures, archaeological finds, decorative elements in architecture. The subject is faced keeping in mind the purposes and needs the models should or could meet, and which are the challenging steps to become a more common tool. To name one, a fundamental aspect is bridging gaps betwe...

  14. 3D imaging of optically cleared tissue using a simplified CLARITY method and on-chip microscopy

    KAUST Repository

    Zhang, Yibo

    2017-08-12

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

  15. A 3-D Novel Highly Chaotic System with Four Quadratic Nonlinearities, its Adaptive Control and Anti-Synchronization with Unknown Parameters

    Directory of Open Access Journals (Sweden)

    S. Vaidyanathan

    2014-11-01

    Full Text Available This research work proposes a seven-term 3-D novel dissipative chaotic system with four quadratic nonlinearities. The Lyapunov exponents of the 3-D novel chaotic system are obtained as L1 = 11.36204, L2 = 0 and L3 = –47.80208. Since the sum of the Lyapunov exponents is negative, the 3-D novel chaotic system is dissipative. Also, the Kaplan-Yorke dimension of the 3-D novel chaotic system is obtained as DKY = 2.23769. The maximal Lyapunov exponent (MLE of the novel chaotic system is L1 = 11.36204, which is a large value for a polynomial chaotic system. Thus, the proposed 3-D novel chaotic system is highly chaotic. The phase portraits of the novel chaotic system simulated using MATLAB depict the highly chaotic attractor of the novel system. This research work also discusses other qualitative properties of the system. Next, an adaptive controller is designed to stabilize the 3-D novel chaotic system with unknown parameters. Also, an adaptive synchronizer is designed to achieve anti-synchronization of the identical 3-D novel chaotic systems with unknown parameters. The adaptive results derived in this work are established using Lyapunov stability theory. MATLAB simulations have been shown to illustrate and validate all the main results derived in this work.

  16. DYNA3D: A nonlinear, explicit, three-dimensional finite element code for solid and structural mechanics, User manual. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Whirley, R.G.; Engelmann, B.E.

    1993-11-01

    This report is the User Manual for the 1993 version of DYNA3D, and also serves as a User Guide. DYNA3D is a nonlinear, explicit, finite element code for analyzing the transient dynamic response of three-dimensional solids and structures. The code is fully vectorized and is available on several computer platforms. DYNA3D includes solid, shell, beam, and truss elements to allow maximum flexibility in modeling physical problems. Many material models are available to represent a wide range of material behavior, including elasticity, plasticity, composites, thermal effects, and rate dependence. In addition, DYNA3D has a sophisticated contact interface capability, including frictional sliding and single surface contact. Rigid materials provide added modeling flexibility. A material model driver with interactive graphics display is incorporated into DYNA3D to permit accurate modeling of complex material response based on experimental data. Along with the DYNA3D Example Problem Manual, this document provides the information necessary to apply DYNA3D to solve a wide range of engineering analysis problems.

  17. Nonlinear Mixing in Optical Multicarrier Systems

    Science.gov (United States)

    Hameed, Mahmood Abdul

    Although optical fiber has a vast spectral bandwidth, efficient use of this bandwidth is still important in order to meet the ever increased capacity demand of optical networks. In addition to wavelength division multiplexing, it is possible to partition multiple low-rate subcarriers into each high speed wavelength channel. Multicarrier systems not only ensure efficient use of optical and electrical components, but also tolerate transmission impairments. The purpose of this research is to understand the impact of mixing among subcarriers in Radio-Over-Fiber (RoF) and high speed optical transmission systems, and experimentally demonstrate techniques to minimize this impact. We also analyze impact of clipping and quantization on multicarrier signals and compare bandwidth efficiency of two popular multiplexing techniques, namely, orthogonal frequency division multiplexing (OFDM) and Nyquist modulation. For an OFDM-RoF system, we present a novel technique that minimizes the RF domain signal-signal beat interference (SSBI), relaxes the phase noise limit on the RF carrier, realizes the full potential of optical heterodyne-based RF carrier generation, and increases the performance-to-cost ratio of RoF systems. We demonstrate a RoF network that shares the same RF carrier for both downlink and uplink, avoiding the need of an additional RF oscillator in the customer unit. For multi-carrier optical transmission, we first experimentally compare performance degradations of coherent optical OFDM and single-carrier Nyquist pulse modulated systems in a nonlinear environment. We then experimentally evaluate SSBI compensation techniques in the presence of semiconductor optical amplifier (SOA) induced nonlinearities for a multicarrier optical system with direct detection. We show that SSBI contamination can be significantly reduced from the data signal when the carrier-to-signal power ratio is sufficiently low.

  18. New Architecture of Optical Interconnect for High-Speed Optical Computerized Data Networks (Nonlinear Response

    Directory of Open Access Journals (Sweden)

    El-Sayed A. El-Badawy

    2008-02-01

    Full Text Available Although research into the use of optics in computers has increased in the last and current decades, the fact remains that electronics is still superior to optics in almost every way. Research into the use of optics at this stage mirrors the research into electronics after the 2nd World War. The advantages of using fiber optics over wiring are the same as the argument for using optics over electronics in computers. Even through totally optical computers are now a reality, computers that combine both electronics and optics, electro-optic hybrids, have been in use for some time. In the present paper, architecture of optical interconnect is built up on the bases of four Vertical-Cavity Surface- Emitting Laser Diodes (VCSELD and two optical links where thermal effects of both the diodes and the links are included. Nonlinear relations are correlated to investigate the power-current and the voltage-current dependences of the four devices. The good performance (high speed of the interconnect is deeply and parametrically investigated under wide ranges of the affecting parameters. The high speed performance is processed through three different effects, namely the device 3-dB bandwidth, the link dispersion characteristics, and the transmitted bit rate (soliton. Eight combinations are investigated; each possesses its own characteristics. The best architecture is the one composed of VCSELD that operates at 850 nm and the silica fiber whatever the operating set of causes. This combination possesses the largest device 3-dB bandwidth, the largest link bandwidth and the largest soliton transmitted bit rate. The increase of the ambient temperature reduces the high-speed performance of the interconnect

  19. New Architecture of Optical Interconnect for High-Speed Optical Computerized Data Networks (Nonlinear Response

    Directory of Open Access Journals (Sweden)

    El-Sayed A. El-Badawy

    2008-02-01

    Full Text Available Although research into the use of optics in computers has increased in the last and current decades, the fact remains that electronics is still superior to optics in almost every way. Research into the use of optics at this stage mirrors the research into electronics after the 2nd World War. The advantages of using fiber optics over wiring are the same as the argument for using optics over electronics in computers. Even through totally optical computers are now a reality, computers that combine both electronics and optics, electro-optic hybrids, have been in use for some time. In the present paper, architecture of optical interconnect is built up on the bases of four Vertical-Cavity Surface- Emitting Laser Diodes (VCSELD and two optical links where thermal effects of both the diodes and the links are included. Nonlinear relations are correlated to investigate the power-current and the voltage-current dependences of the four devices. The good performance (high speed of the interconnect is deeply and parametrically investigated under wide ranges of the affecting parameters. The high speed performance is processed through three different effects, namely the device 3-dB bandwidth, the link dispersion characteristics, and the transmitted bit rate (soliton. Eight combinations are investigated; each possesses its own characteristics. The best architecture is the one composed of VCSELD that operates at 850 nm and the silica fiber whatever the operating set of causes. This combination possesses the largest device 3-dB bandwidth, the largest link bandwidth and the largest soliton transmitted bit rate. The increase of the ambient temperature reduces the high-speed performance of the interconnect

  20. Quantum Information Processing using Nonlinear Optical Effects

    DEFF Research Database (Denmark)

    Andersen, Lasse Mejling

    of the converted idler depends on the other pump. This allows for temporal-mode-multiplexing. When the effects of nonlinear phase modulation (NPM) are included, the phases of the natural input and output modes are changed, reducing the separability. These effects are to some degree mediated by pre......This PhD thesis treats applications of nonlinear optical effects for quantum information processing. The two main applications are four-wave mixing in the form of Bragg scattering (BS) for quantum-state-preserving frequency conversion, and sum-frequency generation (SFG) in second-order nonlinear...... to obtain a 100 % conversion efficiency is to use multiple stages of frequency conversion, but this setup suffers from the combined effects of NPM. This problem is circumvented by using asymmetrically pumped BS, where one pump is continuous wave. For this setup, NPM is found to only lead to linear phase...

  1. Holographic 3D multi-spot two-photon excitation for fast optical stimulation in brain

    Science.gov (United States)

    Takiguchi, Yu; Toyoda, Haruyoshi

    2017-04-01

    We report here a holographic high speed accessing microscope of sensory-driven synaptic activity across all inputs to single living neurons in the context of the intact cerebral cortex. This system is based on holographic multiple beam generation with spatial light modulator, we have demonstrated performance of the holographic excitation efficiency in several in vitro prototype system. 3D weighted iterative Fourier Transform method using the Ewald sphere in consideration of calculation speed has been adopted; multiple locations can be patterned in 3D with single hologram. Standard deviation of intensities of spots are still large due to the aberration of the system and/or hologram calculation, we successfully excited multiple locations of neurons in living mouse brain to monitor the calcium signals.

  2. Optically nonlinear Langmuir Blodgett films

    CERN Document Server

    Amiri, M A

    2003-01-01

    A series of novel amphiphilic molecules plus a new class of chevron-shaped materials, without aliphatic tails, were designed, synthesised and non-centrosymmetrically aligned by the Langmuir-Blodgett technique. Their LB films exhibited optical second-harmonic generation (SHG). The chevron-shaped molecules have a central cationic acceptor and two pi-bridged donor groups with an angle of ca. 120 deg between the charge-transfer axes of the D-pi-(A sup +)-pi-D unit. A monolayer LB film of a representative example, 1-butyl-2,6-bis[2- (4-dibutylaminophenyl)vinyl]pyridinium iodide, has an effective susceptibility, chi sup ( sup 2 sup ) sub e sub f sub f , of 120 pm V sup - sup 1 at 1064 nm, a thickness of 1.16 nm and an area in contact with the substrate of 0.91 nm sup 2 molecule sup - sup 1. The second-harmonic intensity (1.6 x 10 sup - sup 4 versus quartz) is similar to those of the extensively studied conventional amphiphilic hemicyanines but as a result of non-centrosymmetric alignment, without the need for long ...

  3. Manufacturing of polymer optical waveguides using self-assembly effect on pre-conditioned 3D-thermoformed flexible substrates

    Science.gov (United States)

    Hoffmann, Gerd-Albert; Wolfer, Tim; Zeitler, Jochen; Franke, Jörg; Suttmann, Oliver; Overmeyer, Ludger

    2017-02-01

    Optical data communication is increasingly interesting for many applications in industrial processes. Therefore mass production is required to meet the requested price and lot sizes. Polymer optical waveguides show great promises to comply with price requirements while providing sufficient optical quality for short range data transmission. A high efficient fabrication technology using polymer materials could be able to create the essential backbone for 3D-optical data transmission in the future. The approach for high efficient fabrication technology of micro optics described in this paper is based on a self-assembly effect of fluids on preconditioned 3D-thermoformed polymer foils. Adjusting the surface energy on certain areas on the flexible substrate by flexographic printing mechanism is presented in this paper. With this technique conditioning lines made of silicone containing UV-varnish are printed on top of the foils and create gaps with the exposed substrate material in between. Subsequent fabrication processes are selected whether the preconditioned foil is coated with acrylate containing waveguide material prior or after the thermoforming process. Due to the different surface energy this material tends to dewet from the conditioning lines. It acts like regional barriers and sets the width of the arising waveguides. With this fabrication technology it is possible to produce multiple waveguides with a single coating process. The relevant printing process parameters that affect the quality of the generated waveguides are discussed and results of the produced waveguides with width ranging from 10 to 300 μm are shown.

  4. Towards a Noninvasive Intracranial Tumor Irradiation Using 3D Optical Imaging and Multimodal Data Registration

    Science.gov (United States)

    Posada, R.; Daul, Ch.; Wolf, D.; Aletti, P.

    2007-01-01

    Conformal radiotherapy (CRT) results in high-precision tumor volume irradiation. In fractioned radiotherapy (FRT), lesions are irradiated in several sessions so that healthy neighbouring tissues are better preserved than when treatment is carried out in one fraction. In the case of intracranial tumors, classical methods of patient positioning in the irradiation machine coordinate system are invasive and only allow for CRT in one irradiation session. This contribution presents a noninvasive positioning method representing a first step towards the combination of CRT and FRT. The 3D data used for the positioning is point clouds spread over the patient's head (CT-data usually acquired during treatment) and points distributed over the patient's face which are acquired with a structured light sensor fixed in the therapy room. The geometrical transformation linking the coordinate systems of the diagnosis device (CT-modality) and the 3D sensor of the therapy room (visible light modality) is obtained by registering the surfaces represented by the two 3D point sets. The geometrical relationship between the coordinate systems of the 3D sensor and the irradiation machine is given by a calibration of the sensor position in the therapy room. The global transformation, computed with the two previous transformations, is sufficient to predict the tumor position in the irradiation machine coordinate system with only the corresponding position in the CT-coordinate system. Results obtained for a phantom show that the mean positioning error of tumors on the treatment machine isocentre is 0.4 mm. Tests performed with human data proved that the registration algorithm is accurate (0.1 mm mean distance between homologous points) and robust even for facial expression changes. PMID:18364992

  5. Time-reversed wave mixing in nonlinear optics.

    Science.gov (United States)

    Zheng, Yuanlin; Ren, Huaijin; Wan, Wenjie; Chen, Xianfeng

    2013-11-19

    Time-reversal symmetry is important to optics. Optical processes can run in a forward or backward direction through time when such symmetry is preserved. In linear optics, a time-reversed process of laser emission can enable total absorption of coherent light fields inside an optical cavity of loss by time-reversing the original gain medium. Nonlinearity, however, can often destroy such symmetry in nonlinear optics, making it difficult to study time-reversal symmetry with nonlinear optical wave mixings. Here we demonstrate time-reversed wave mixings for optical second harmonic generation (SHG) and optical parametric amplification (OPA) by exploring this well-known but underappreciated symmetry in nonlinear optics. This allows us to observe the annihilation of coherent beams. Our study offers new avenues for flexible control in nonlinear optics and has potential applications in efficient wavelength conversion, all-optical computing.

  6. Pre-Processing of Point-Data from Contact and Optical 3D Digitization Sensors

    Directory of Open Access Journals (Sweden)

    Mirko Soković

    2012-01-01

    Full Text Available Contemporary 3D digitization systems employed by reverse engineering (RE feature ever-growing scanning speeds with the ability to generate large quantity of points in a unit of time. Although advantageous for the quality and efficiency of RE modelling, the huge number of point datas can turn into a serious practical problem, later on, when the CAD model is generated. In addition, 3D digitization processes are very often plagued by measuring errors, which can be attributed to the very nature of measuring systems, various characteristics of the digitized objects and subjective errors by the operator, which also contribute to problems in the CAD model generation process. This paper presents an integral system for the pre-processing of point data, i.e., filtering, smoothing and reduction, based on a cross-sectional RE approach. In the course of the proposed system development, major emphasis was placed on the module for point data reduction, which was designed according to a novel approach with integrated deviation analysis and fuzzy logic reasoning. The developed system was verified through its application on three case studies, on point data from objects of versatile geometries obtained by contact and laser 3D digitization systems. The obtained results demonstrate the effectiveness of the system.

  7. Making of a nonlinear optical cavity

    CERN Document Server

    Martínez-Lorente, R; Esteban-Martín, A; García-Monreal, J; Roldán, E; Silva, F

    2016-01-01

    In the article we explain in detail how to build a photorefractive oscillator (PRO), which is a laser-pumped nonlinear optical cavity containing a photorefractive crystal. The specific PRO whose construction we describe systematically, is based on a Fabry-Perot optical cavity working in a non-degenerate four wave-mixing configuration. This particular PRO has the property that the generated beam exhibits laser-like phase invariance and, as an application, we show how a suitably modulated injected beam converts the output field from phase-invariant into phase-bistable. While the emphasis is made on the making of the experimental device and on the way measurements are implemented, some introduction to the photorefractive effect as well as to the necessary concepts of nonlinear dynamics are also given, so that the article is reasonably self-contained.

  8. Impact of nonlinearities on fiber optic communications

    CERN Document Server

    2011-01-01

    This book covers the recent progress in fiber-optic communication systems with a main focus on the impact of fiber nonlinearities on system performance. There has been significant progress in coherent communication systems in the past few years due to the advances in digital signal processing techniques. This has led to renewed interest in fiber linear and nonlinear impairments as well as techniques to mitigate them in the electrical domain. In this book, the reader will find all the important topics of fiber optic communication systems in one place, with in-depth coverage by the experts of each sub-topic. Pioneers from each of the sub-topics have been invited to contribute. Each chapter will have a section on fundamentals as well as reviews of literature and of recent developments. Readers will benefit from this approach since many of the conference proceedings and journal articles mainly focus on the authors’ research, without spending space on preliminaries.

  9. Nonlinear optics of astaxanthin thin films

    Science.gov (United States)

    Esser, A.; Fisch, Herbert; Haas, Karl-Heinz; Haedicke, E.; Paust, J.; Schrof, Wolfgang; Ticktin, Anton

    1993-02-01

    Carotinoids exhibit large nonlinear optical properties due to their extended (pi) -electron system. Compared to other polyenes which show a broad distribution of conjugation lengths, carotinoids exhibit a well defined molecular structure, i.e. a well defined conjugation length. Therefore the carotinoid molecules can serve as model compounds to study the relationship between structure and nonlinear optical properties. In this paper the synthesis of four astaxanthins with C-numbers ranging from 30 to 60, their preparation into thin films, wavelength dispersive Third Harmonic Generation (THG) measurements and some molecular modelling calculations will be presented. Resonant (chi) (3) values reach 1.2(DOT)10-10 esu for C60 astaxanthin. In the nonresonant regime a figure of merit (chi) (3)/(alpha) of several 10-13 esu-cm is demonstrated.

  10. Writing of 3D optical integrated circuits with ultrashort laser pulses in the presence of strong spherical aberration

    Science.gov (United States)

    Bukharin, M. A.; Skryabin, N. N.; Khudyakov, D. V.; Vartapetov, S. K.

    2016-09-01

    A novel technique was proposed for 3D femtosecond writing of waveguides and optical integrated circuits in the presence of strong spherical aberration, caused by inscription at significantly different depth under the surface of optical glasses and crystals. Strong negative effect of spherical aberration and related asymmetry of created structures was reduced due to transition to the cumulative thermal regime of femtosecond interaction with the material. The differences in the influence of spherical aberration effect in a broad depth range (larger than 200 µm) was compensated by dynamic adjustment of laser pulse energy during the process of waveguides recording. The presented approach has been experimentally implemented in fused silica. Obtained results can be used in production of a broad class of femtosecond written three-dimensional integrated optical systems, inscripted at non-optimal (for focusing lens) optical depth or in significantly extended range of depths.

  11. Nonlinear optical studies of organic monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Y.R.

    1988-02-01

    Second-order nonlinear optical effects are forbidden in a medium with inversion symmetry, but are necessarily allowed at a surface where the inversion summary is broken. They are often sufficiently strong so that a submonolayer perturbation of the surface can be readily detected. They can therefore be used as effective tools to study monolayers adsorbed at various interfaces. We discuss here a number of recent experiments in which optical second harmonic generation (SHG) and sum-frequency generation (SFG) are employed to probe and characterize organic monolayers. 15 refs., 5 figs.

  12. Topological nature of nonlinear optical effects in solids

    OpenAIRE

    Morimoto, Takahiro; Nagaosa, Naoto

    2015-01-01

    There are a variety of nonlinear optical effects including higher harmonic generations, photovoltaic effects, and nonlinear Kerr rotations. They are realized by the strong light irradiation to materials that results in nonlinear polarizations in the electric field. These are of great importance in studying the physics of excited states of the system as well as for applications to optical devices and solar cells. Nonlinear properties of materials are usually described by the nonlinear suscepti...

  13. Enhanced optical nonlinearities in air-cladding silicon pedestal waveguides

    CERN Document Server

    Zhang, Yaojing; Yao, Yifei; Tsang, Hon Ki

    2016-01-01

    The third-order optical nonlinearity in optical waveguides has found applications in optical switching, optical wavelength conversion, optical frequency comb generation, and ultrafast optical signal processing. The development of an integrated waveguide platform with a high nonlinearity is therefore important for nonlinear integrated photonics. Here, we report the observation of an enhancement in the nonlinearity of an air-cladding silicon pedestal waveguide. We observe enhanced nonlinear spectral broadening compared to a conventional silicon-on-insulator waveguide. At the center wavelength of 1555 nm, the nonlinear-index coefficient of air-cladding silicon pedestal waveguide is measured to be about 5% larger than that of a conventional silicon-on-insulator waveguide. We observe enhanced spectral broadening from self-phase modulation of an optical pulse in the pedestal waveguide. The interaction of light with the confined acoustic phonons in the pedestal structure gives rise to a larger nonlinear-index coeffi...

  14. Nonlinear inversion schemes for fluorescence optical tomography.

    Science.gov (United States)

    Freiberger, Manuel; Egger, Herbert; Scharfetter, Hermann

    2010-11-01

    Fluorescence optical tomography is a non-invasive imaging modality that employs the absorption and re-emission of light by fluorescent dyes. The aim is to reconstruct the fluorophore distribution in a body from measurements of light intensities at the boundary. Due to the diffusive nature of light propagation in tissue, fluorescence tomography is a nonlinear and severely ill-posed problem, and some sort of regularization is required for a stable solution. In this paper we investigate reconstruction methods based on Tikhonov regularization with nonlinear penalty terms, namely total-variation regularization and a levelset-type method using a nonlinear parameterization of the unknown function. Moreover, we use the full threedimensional nonlinear forward model, which arises from the governing system of partial differential equations. We discuss the numerical realization of the regularization schemes by Newtontype iterations, present some details of the discretization by finite element methods, and outline the efficient implementation of sensitivity systems via adjoint methods. As we will demonstrate in numerical tests, the proposed nonlinear methods provide better reconstructions than standard methods based on linearized forward models and linear penalty terms. We will additionally illustrate, that the careful discretization of the methods derived on the continuous level allows to obtain reliable, mesh independent reconstruction algorithms.

  15. WebTOP: A 3D Interactive System for Teaching and Learning Optics

    Science.gov (United States)

    Mzoughi, Taha; Herring, S. Davis; Foley, John T.; Morris, Matthew J.; Gilbert, Peter J.

    2007-01-01

    WebTOP is a three-dimensional, Web-based, interactive computer graphics system that helps instructors teach and students learn about waves and optics. Current subject areas include waves, geometrical optics, reflection and refraction, polarization, interference, diffraction, lasers, and scattering. Some of the topics covered are suited for…

  16. Fiber-optic nonlinear endomicroscopy with focus scanning by using shape memory alloy actuation

    Science.gov (United States)

    Wu, Yicong; Zhang, Yuying; Xi, Jiefeng; Li, Ming-Jun; Li, Xingde

    2010-01-01

    A miniature fiber optic endomicroscope with built-in dynamic focus scanning capability is developed for the first time for 3-D two-photon fluorescence (TPF) imaging of biological samples. Fast 2-D lateral beam scanning is realized by resonantly vibrating a double-clad fiber cantilever with a tubular piezoactuator. Slow axial scanning is achieved by moving the distal end of the imaging probe with an extremely compact electrically driven shape memory alloy (SMA). The 10-mm-long SMA allows 150-μm contractions with a driving voltage varying only from 50 to 100 mV. The response of the SMA contraction with the applied voltage is nonlinear, but repeatable and can be accurately calibrated. Depth-resolved imaging of acriflavine-stained biological tissues and unstained white paper with the endomicroscope is performed, and the results demonstrate the feasibility of 3-D nonlinear optical imaging with the SMA-based scanning fiber-optic endomicroscope. PMID:21198147

  17. Correlation between Optic Nerve Parameters Obtained Using 3D Nonmydriatic Retinal Camera and Optical Coherence Tomography: Interobserver Agreement on the Disc Damage Likelihood Scale

    Directory of Open Access Journals (Sweden)

    Jae Wook Han

    2014-01-01

    Full Text Available Purpose. To compare stereometric parameters obtained by three-dimensional (3D optic disc photography and optical coherence tomography (OCT and assess interobserver agreement on the disc damage likelihood scale (DDLS. Methods. This retrospective study included 190 eyes from 190 patients classified as normal, glaucoma suspect, or glaucomatous. Residents at different levels of training completed the DDLS for each patient before and after attending a training module. 3D optic disc photography and OCT were performed on each eye, and correlations between the DDLS and various parameters obtained by each device were calculated. Results. We found moderate agreement (weighted kappa value, 0.59 ± 0.03 between DDLS scores obtained by 3D optic disc photography and the glaucoma specialist. The weighted kappa values for agreement and interobserver concordance increased among residents after the training module. Interobserver concordance was the poorest at DDLS stages 5 and 6. The DDLS scored by the glaucoma specialist had the highest predictability value (0.941. Conclusions. The DDLS obtained by 3D optic disc photography is a useful diagnostic tool for glaucoma. A supervised teaching program increased trainee interobserver agreement on the DDLS. DDLS stages 5 and 6 showed the poorest interobserver agreement, suggesting that caution is required when recording these stages.

  18. Correlation between Optic Nerve Parameters Obtained Using 3D Nonmydriatic Retinal Camera and Optical Coherence Tomography: Interobserver Agreement on the Disc Damage Likelihood Scale.

    Science.gov (United States)

    Han, Jae Wook; Cho, Soon Young; Kang, Kui Dong

    2014-01-01

    Purpose. To compare stereometric parameters obtained by three-dimensional (3D) optic disc photography and optical coherence tomography (OCT) and assess interobserver agreement on the disc damage likelihood scale (DDLS). Methods. This retrospective study included 190 eyes from 190 patients classified as normal, glaucoma suspect, or glaucomatous. Residents at different levels of training completed the DDLS for each patient before and after attending a training module. 3D optic disc photography and OCT were performed on each eye, and correlations between the DDLS and various parameters obtained by each device were calculated. Results. We found moderate agreement (weighted kappa value, 0.59 ± 0.03) between DDLS scores obtained by 3D optic disc photography and the glaucoma specialist. The weighted kappa values for agreement and interobserver concordance increased among residents after the training module. Interobserver concordance was the poorest at DDLS stages 5 and 6. The DDLS scored by the glaucoma specialist had the highest predictability value (0.941). Conclusions. The DDLS obtained by 3D optic disc photography is a useful diagnostic tool for glaucoma. A supervised teaching program increased trainee interobserver agreement on the DDLS. DDLS stages 5 and 6 showed the poorest interobserver agreement, suggesting that caution is required when recording these stages.

  19. Measurement of dynamic cell-induced 3D displacement fields in vitro for traction force optical coherence microscopy.

    Science.gov (United States)

    Mulligan, Jeffrey A; Bordeleau, François; Reinhart-King, Cynthia A; Adie, Steven G

    2017-02-01

    Traction force microscopy (TFM) is a method used to study the forces exerted by cells as they sense and interact with their environment. Cell forces play a role in processes that take place over a wide range of spatiotemporal scales, and so it is desirable that TFM makes use of imaging modalities that can effectively capture the dynamics associated with these processes. To date, confocal microscopy has been the imaging modality of choice to perform TFM in 3D settings, although multiple factors limit its spatiotemporal coverage. We propose traction force optical coherence microscopy (TF-OCM) as a novel technique that may offer enhanced spatial coverage and temporal sampling compared to current methods used for volumetric TFM studies. Reconstructed volumetric OCM data sets were used to compute time-lapse extracellular matrix deformations resulting from cell forces in 3D culture. These matrix deformations revealed clear differences that can be attributed to the dynamic forces exerted by normal versus contractility-inhibited NIH-3T3 fibroblasts embedded within 3D Matrigel matrices. Our results are the first step toward the realization of 3D TF-OCM, and they highlight the potential use of OCM as a platform for advancing cell mechanics research.

  20. Light engine and optics for HELIUM3D auto-stereoscopic laser scanning display

    OpenAIRE

    Aksit, K.; Olcer, S.; Erden, E.; Kishore, V. C.; Urey, H.; Willman, E.; Baghsiahi, H.; Day, S. E.; Selviah, D. R.; Fernandez, F. A.; Surman, P.

    2011-01-01

    This paper presents a laser based auto-stereoscopic 3D display technique and a prototype utilizing a dual projector light engine. The solution described is able to form dynamic exit pupils under the control of a multi-user head-tracker. A prototype completed recently is able to provide a glasses-free solution for a single user at a fixed position. At the end of the prototyping phase it is expected to enable a multiple user interface with an integration of the pupil tracker and the spatial lig...

  1. 3D monitoring and quality control using intraoral optical camera systems.

    Science.gov (United States)

    Mehl, A; Koch, R; Zaruba, M; Ender, A

    2013-01-01

    The quality of intraoral scanning systems is steadily improving, and they are becoming easier and more reliable to operate. This opens up possibilities for routine clinical applications. A special aspect is that overlaying (superimposing) situations recorded at different times facilitates an accurate three-dimensional difference analysis. Such difference analyses can also be used to advantage in other areas of dentistry where target/actual comparisons are required. This article presents potential indications using a newly developed software, explaining the functionality of the evaluation process and the prerequisites and limitations of 3D monitoring.

  2. Optical stability of 3d transition metal ions doped-cadmium borate glasses towards γ-rays interaction

    Science.gov (United States)

    Marzouk, M.; ElBatal, H.; Eisa, W.

    2016-07-01

    This work reports the preparation of glasses of binary cadmium borate with the basic composition (mol% 45 CdO 55 B2O3) and samples of the same composition containing 0.2 wt% dopants of 3d transition metal (TM) oxides (TiO2 → CuO). The glasses have been investigated by combined optical and Fourier Transform infrared spectroscopic measurements before and after being subjected to gamma irradiation with a dose of 8 Mrad (8 × 104 Gy). Optical absorption of the undoped glass before irradiation reveals strong charge transfer UV absorption which is related to the presence of unavoidable contaminated trace iron impurities (mainly Fe3+) within the raw materials used for the preparation of the base cadmium borate glass. The optical spectra of the 3d TM ions exhibit characteristic bands which are related the stable oxidation state of the 3d TM ions within the host glass. Gamma irradiation produces some limited variations in the optical spectra due to the stability of the host glass containing high percent 45 mol% of heavy metal oxide (CdO) which causes some shielding effects towards irradiation. From the absorption edge data, the values of the optical band gap Eopt and Urbach energy (∆E) have been calculated. The values of the optical energy gap are found to be dependent on the glass composition. Infrared absorption spectral measurements reveal characteristic absorption bands due to both triangular and tetrahedral borate groups with the BO3 units vibrations more intense than BO4 units due to the known limit value for the change of BO3 to BO4 groups. The introduction of 3d TM ions with the doping level (0.2 wt%) causes no changes in the number or position of the IR bands because of the presence of TM ions in modifying sites in the glass network. It is observed that gamma irradiation causes some limited changes in the FT-IR spectral bands due to the stability of the host heavy cadmium borate glass.

  3. 3D documentation of footwear impressions and tyre tracks in snow with high resolution optical surface scanning.

    Science.gov (United States)

    Buck, Ursula; Albertini, Nicola; Naether, Silvio; Thali, Michael J

    2007-09-13

    The three-dimensional documentation of footwear and tyre impressions in snow offers an opportunity to capture additional fine detail for the identification as present photographs. For this approach, up to now, different casting methods have been used. Casting of footwear impressions in snow has always been a difficult assignment. This work demonstrates that for the three-dimensional documentation of impressions in snow the non-destructive method of 3D optical surface scanning is suitable. The new method delivers more detailed results of higher accuracy than the conventional casting techniques. The results of this easy to use and mobile 3D optical surface scanner were very satisfactory in different meteorological and snow conditions. The method is also suitable for impressions in soil, sand or other materials. In addition to the side by side comparison, the automatic comparison of the 3D models and the computation of deviations and accuracy of the data simplify the examination and delivers objective and secure results. The results can be visualized efficiently. Data exchange between investigating authorities at a national or an international level can be achieved easily with electronic data carriers.

  4. 3D optical two-mirror scanner with focus-tunable lens.

    Science.gov (United States)

    Pokorny, Petr; Miks, Antonin

    2015-08-01

    The paper presents formulas for a ray tracing in the optical system of two-mirror optical scanner with a focus-tunable lens. Furthermore, equations for the calculation of focal length which ensure focusing of a beam in the desired point in a detection plane are derived. The uncertainty description of such focal length follows as well. The chosen vector approach is general; therefore, the application of formulas in various configurations of the optical systems is possible. In the example situation, the authors derived formulas for mirrors' rotations and the focal length depending on the position of the point in the detection plane.

  5. Third-Order Nonlinear Optical Susceptibility of Indium Phosphide Nanocrystals

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-Li; WANG Dong; CHEN Guang-De; LIU Hui

    2007-01-01

    InP nanocrystals synthesized by refluxing and annealing of organic solvent are determined from XRD measurements to have an average granularity of 25 nm. The nonlinear optical properties of the InP nanocrystals studied by using laser Z-scan technique with 50ps pulses at 532nm are found to reveal strong nonlinear optical properties and two-photon absorption phenomenon. Also, the nonlinear absorption coefficient, the nonlinear refractive index and the third-order nonlinear optical susceptibility are determined by experiments, in which the nonlinear refractive index is three orders of magnitude larger than that of bulk InP.

  6. Treating benign optic nerve tumors with a 3-D conformal plan

    Energy Technology Data Exchange (ETDEWEB)

    Millunchick, Cheryl Hope, E-mail: mordechaimillunchick@gmail.com [Rush University Medical Center, Radiation Oncology, Chicago, IL (United States)

    2013-07-01

    A 68 year old male patient presented for radiation therapy for treatment of a benign tumor, a glioma of his left optic nerve. The radiation oncologist intended to prescribe 52.2 Gy to the planning target volume, while maintaining a maximum of 54 Gy to the optic nerves and the optic chiasm and a maximum of 40–45 Gy to the globes in order to minimize the possibility of damaging the optic system, which is especially important as this is a benign tumor. The dosimetrist devised a conformal non-coplanar three-dimensional plan with a slightly weighted forward planning component. This plan was created in approximately 15 minutes after the critical organs and the targets were delineated and resulted in an extremely conformal and homogenous plan, treating the target while sparing the nearby critical structures. This approach can also be extended to other tumors in the brain - benign or malignant.

  7. Multicolor 3D super-resolution imaging by quantum dot stochastic optical reconstruction microscopy.

    Science.gov (United States)

    Xu, Jianquan; Tehrani, Kayvan F; Kner, Peter

    2015-03-24

    We demonstrate multicolor three-dimensional super-resolution imaging with quantum dots (QSTORM). By combining quantum dot asynchronous spectral blueing with stochastic optical reconstruction microscopy and adaptive optics, we achieve three-dimensional imaging with 24 nm lateral and 37 nm axial resolution. By pairing two short-pass filters with two appropriate quantum dots, we are able to image single blueing quantum dots on two channels simultaneously, enabling multicolor imaging with high photon counts.

  8. 3D visualization of the initial Yersinia ruckeri infection route in rainbow trout (Oncorhynchus mykiss) by optical projection tomography

    DEFF Research Database (Denmark)

    Otani, Maki; Villumsen, Kasper Rømer; Kragelund Strøm, Helene;

    2014-01-01

    , optical projection tomography (OPT), a novel three-dimensional (3D) bio-imaging technique, was applied. OPT not only enables the visualization of Y. ruckeri on mucosal surfaces but also the 3D spatial distribution in whole organs, without sectioning. Rainbow trout were infected by bath challenge exposure...... as 1 minute post infection. Both OPT and IHC analysis confirmed that the secondary gill lamellae were the only tissues infected at this early time point, indicating that Y. ruckeri initially infects gill epithelial cells. The experimentally induced infection caused septicemia, and Y. ruckeri was found...... trout. Using OPT scanning it was possible to visualize the initial route of entry, as well as secondary infection routes along with the proliferation and spread of Y. ruckeri, ultimately causing significant mortality in the exposed rainbow trout. These results demonstrate that OPT is a state...

  9. DSP Approach to the Design of Nonlinear Optical Devices

    Directory of Open Access Journals (Sweden)

    Steve Blair

    2005-06-01

    Full Text Available Discrete-time signal processing (DSP tools have been used to analyze numerous optical filter configurations in order to optimize their linear response. In this paper, we propose a DSP approach to design nonlinear optical devices by treating the desired nonlinear response in the weak perturbation limit as a discrete-time filter. Optimized discrete-time filters can be designed and then mapped onto a specific optical architecture to obtain the desired nonlinear response. This approach is systematic and intuitive for the design of nonlinear optical devices. We demonstrate this approach by designing autoregressive (AR and autoregressive moving average (ARMA lattice filters to obtain a nonlinear phase shift response.

  10. 3D printed disposable optics and lab-on-a-chip devices for chemical sensing with cell phones

    Science.gov (United States)

    Comina, G.; Suska, A.; Filippini, D.

    2017-02-01

    Digital manufacturing (DM) offers fast prototyping capabilities and great versatility to configure countless architectures at affordable development costs. Autonomous lab-on-a-chip (LOC) devices, conceived as only disposable accessory to interface chemical sensing to cell phones, require specific features that can be achieved using DM techniques. Here we describe stereo-lithography 3D printing (SLA) of optical components and unibody-LOC (ULOC) devices using consumer grade printers. ULOC devices integrate actuation in the form of check-valves and finger pumps, as well as the calibration range required for quantitative detection. Coupling to phone camera readout depends on the detection approach, and includes different types of optical components. Optical surfaces can be locally configured with a simple polishing-free post-processing step, and the representative costs are 0.5 US$/device, same as ULOC devices, both involving fabrication times of about 20 min.

  11. Feasibility study of a single-shot 3D electron bunch shape monitor with an electro-optic sampling technique

    Directory of Open Access Journals (Sweden)

    Yuichi Okayasu

    2013-05-01

    Full Text Available We developed a three-dimensional electron bunch charge distribution (3D-BCD monitor with single-shot detection, and a spectral decoding based electro-optic (EO sampling technique for a nondestructive monitor enables real-time reconstruction of the three-dimensional distribution of a bunch charge. We realized three goals by simultaneously probing a number of Pockels EO crystals that surround the electron beam axis with hollow and radial polarized laser pulses. First, we performed a feasibility test as a simple case of a 3D-BCD monitor probing two ZnTe crystals as EO detectors installed on the opposite angle to the electron beam axis and confirmed that we simultaneously obtained both EO signals. Since the adopted hollow probe laser pulse is not only radially polarized but also temporally shifted azimuthally, some disorders in the radial polarization distribution of such a laser pulse were numerically analyzed with a plane-wave expansion method. Based on the above investigations, the 3D-BCD monitor is feasible both in experimental and numerical estimations. Furthermore, we previously developed a femtosecond response organic crystal as a Pockels EO detector and a broadband probe laser (≥350  nm in FWHM; the 3D-BCD monitor realizes 30- to 40-fs (FWHM temporal resolution. Eventually, the monitor is expected to be equipped in such advanced accelerators as XFEL to measure and adjust the electron bunch charge distribution in real time. The 3D-BCD measurement works as a critical tool to provide feedback to seeded FELs.

  12. Analysis, Adaptive Control and Adaptive Synchronization of a Nine-Term Novel 3-D Chaotic System with Four Quadratic Nonlinearities and its Circuit Simulation

    Directory of Open Access Journals (Sweden)

    S. Vaidyanathan

    2014-11-01

    Full Text Available This research work describes a nine-term novel 3-D chaotic system with four quadratic nonlinearities and details its qualitative properties. The phase portraits of the 3-D novel chaotic system simulated using MATLAB, depict the strange chaotic attractor of the system. For the parameter values chosen in this work, the Lyapunov exponents of the novel chaotic system are obtained as L1 = 6.8548, L2 = 0 and L3 = −32.8779. Also, the Kaplan-Yorke dimension of the novel chaotic system is obtained as DKY = 2.2085. Next, an adaptive controller is design to achieve global stabilization of the 3-D novel chaotic system with unknown system parameters. Moreover, an adaptive controller is designed to achieve global chaos synchronization of two identical novel chaotic systems with unknown system parameters. Finally, an electronic circuit realization of the novel chaotic system is presented using SPICE to confirm the feasibility of the theoretical model.

  13. Scanning laser optical computed tomography system for large volume 3D dosimetry

    Science.gov (United States)

    Dekker, Kurtis H.; Battista, Jerry J.; Jordan, Kevin J.

    2017-04-01

    Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.

  14. Scanning laser optical computed tomography system for large volume 3D dosimetry.

    Science.gov (United States)

    Dekker, Kurtis H; Battista, Jerry J; Jordan, Kevin J

    2017-04-07

    Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.

  15. Optical 3D Nano-fabrication: Drawing or Growing? (Conference Presentation)

    Science.gov (United States)

    Kawata, Satoshi

    2016-05-01

    Conventional nanotechnology based on the lithography and scanning probe microscopy is limited to 2D fabrication and modification. Here, I will talk about the method for 3D laser fabrication with two-photon polymerization [1], two-photon isomerization [2], and two-photon photo-reduction [3]. Self-growth technology, such as self-grown fiber structures of polymer [4] and self-grown metallic fractal metamaterials structures [5] will be also discussed. [1] S. Kawata, et. al, Nature 412, 697-698, 2001. [2] S. Kawata and Y. Kawata, Chem Rev. 88, 083110, 2006. [3] Y. -Y. Cao, et. al., Small 5, 1144-1148, 2009 [4] S. Shoji and S. Kawata, Appl. Phys. Lett. 75, 737-739, 1999. [5] N. Takeyasu, N. Nishimura, S. Kawata, submitted.

  16. Study of negative hydrogen ion beam optics using the 3D3V PIC model

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, K., E-mail: kmiyamot@naruto-u.ac.jp [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima, 772-8502 (Japan); Nishioka, S.; Goto, I.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, 223-8522 (Japan); Hanada, M.; Kojima, A. [Japan Atomic Energy Agency, 801-1,Mukoyama, Naka, 319-0913 (Japan)

    2015-04-08

    The mechanism of negative ion extraction under real conditions with the complex magnetic field is studied by using the 3D PIC simulation code. The extraction region of the negative ion source for the negative ion based neutral beam injection system in fusion reactors is modelled. It is shown that the E x B drift of electrons is caused by the magnetic filter and the electron suppression magnetic field, and the resultant asymmetry of the plasma meniscus. Furthermore, it is indicated that that the asymmetry of the plasma meniscus results in the asymmetry of negative ion beam profile including the beam halo. It could be demonstrated theoretically that the E x B drift is not significantly weakened by the elastic collisions of the electrons with neutral particles.

  17. Application of optical 3D measurement on thin film buckling to estimate interfacial toughness

    Science.gov (United States)

    Jia, H. K.; Wang, S. B.; Li, L. A.; Wang, Z. Y.; Goudeau, P.

    2014-03-01

    The shape-from-focus (SFF) method has been widely studied as a passive depth recovery and 3D reconstruction method for digital images. An important step in SFF is the calculation of the focus level for different points in an image by using a focus measure. In this work, an image entropy-based focus measure is introduced into the SFF method to measure the 3D buckling morphology of an aluminum film on a polymethylmethacrylate (PMMA) substrate at a micro scale. Spontaneous film wrinkles and telephone-cord wrinkles are investigated after the deposition of a 300 nm thick aluminum film onto the PMMA substrate. Spontaneous buckling is driven by the highly compressive stress generated in the Al film during the deposition process. The interfacial toughness between metal films and substrates is an important parameter for the reliability of the film/substrate system. The height profiles of different sections across the telephone-cord wrinkle can be considered a straight-sided model with uniform width and height or a pinned circular model that has a delamination region characterized by a sequence of connected sectors. Furthermore, the telephone-cord geometry of the thin film can be used to calculate interfacial toughness. The instability of the finite element model is introduced to fit the buckling morphology obtained by SFF. The interfacial toughness is determined to be 0.203 J/m2 at a 70.4° phase angle from the straight-sided model and 0.105 J/m2 at 76.9° from the pinned circular model.

  18. New optical four-quadrant phase detector integrated into a photogate array for small and precise 3D cameras

    Science.gov (United States)

    Schwarte, Rudolf; Xu, Zhanping; Heinol, Horst-Guenther; Olk, Joachim; Buxbaum, Bernd

    1997-03-01

    The photonic mixer device (PMD) is a new electro-optical mixing semiconductor device. Integrated into a line or an array it may contribute a significant improvement in developing an extremely fast, flexible, robust and low cost 3D-solid-state camera. Three dimensional (3D)-cameras are of dramatically increasing interest in industrial automation, especially for production integrated quality control, in- house navigation, etc. The type of 3D-camera here under consideration is based on the principle of time-of-flight respectively phase delay of surface reflected echoes of rf- modulated light. In contrast to 3D-laser radars there is no scanner required since the whole 3D-scene is illuminated simultaneously using intensity-modulated incoherent light, e.g. in the 10 to 1000 MHz range. The rf-modulated light reflected from the 3D-scene represents the total depth information within the local delay of the back scattered phase front. If this incoming wave front is again rf- modulated by a 2D-mixer within the whole receiving aperture we get a quasi-stationary rf-inference pattern respectively rf-interferogram which may be captured by means of a conventional CCD-camera. This procedure is called rf- modulation interferometry (RFMI). Corresponding to first simulative results the new PMD-array will be appropriate to the RFMI-procedure. Though looking like a modified CCD-array or CMOS-photodetector array it will be able to perform both, the pixelwise mixing process for phase delay respectively depth evaluation and the pixelwise light intensity acquisition for gray level or color evaluation. Further advantageous properties are achieved by means of a four- quadrant (4Q)-PMD array which operates as a balanced inphase/quadrature phase (I/Q)-mixer and will be able to capture the total 3D-scene information of several 100,000 voxels within the microsecond(s) - to ms-range.

  19. Fast, high-resolution 3D dosimetry utilizing a novel optical-CT scanner incorporating tertiary telecentric collimation.

    Science.gov (United States)

    Sakhalkar, H S; Oldham, M

    2008-01-01

    This study introduces a charge coupled device (CCD) area detector based optical-computed tomography (optical-CT) scanner for comprehensive verification of radiation dose distributions recorded in nonscattering radiochromic dosimeters. Defining characteristics include: (i) a very fast scanning time of approximately 5 min to acquire a complete three-dimensional (3D) dataset, (ii) improved image formation through the use of custom telecentric optics, which ensures accurate projection images and minimizes artifacts from scattered and stray-light sources, and (iii) high resolution (potentially 50 microm) isotropic 3D dose readout. The performance of the CCD scanner for 3D dose readout was evaluated by comparison with independent 3D readout from the single laser beam OCTOPUS-scanner for the same PRESAGE dosimeters. The OCTOPUS scanner was considered the "gold standard" technique in light of prior studies demonstrating its accuracy. Additional comparisons were made against calculated dose distributions from the ECLIPSE treatment-planning system. Dose readout for the following treatments were investigated: (i) a single rectangular beam irradiation to investigate small field and very steep dose gradient dosimetry away from edge effects, (ii) a 2-field open beam parallel-opposed irradiation to investigate dosimetry along steep dose gradients, and (iii) a 7-field intensity modulated radiation therapy (IMRT) irradiation to investigate dosimetry for complex treatment delivery involving modulation of fluence and for dosimetry along moderate dose gradients. Dose profiles, dose-difference plots, and gamma maps were employed to evaluate quantitative estimates of agreement between independently measured and calculated dose distributions. Results indicated that dose readout from the CCD scanner was in agreement with independent gold-standard readout from the OCTOPUS-scanner as well as the calculated ECLIPSE dose distribution for all treatments, except in regions within a few

  20. 3D-integrated optics component for astronomical spectro-interferometry.

    Science.gov (United States)

    Saviauk, Allar; Minardi, Stefano; Dreisow, Felix; Nolte, Stefan; Pertsch, Thomas

    2013-07-01

    We present the experimental characterization of a spectro-interferometry setup based on a laser-written three-dimensional integrated optics component. By exploiting the interferometric capability of a two-dimensional array of evanescently coupled waveguides, we measure the mutual coherence properties of three different polychromatic optical fields. Direct application of our discrete beam combiner (DBC) component is astronomical interferometry. The DBC can be scaled up to combine arbitrary large number of telescopes for the determination of coherence properties of astronomical targets. Besides applications to astronomy, the DBC can be also applied to optical integrated metrology system requiring nanometric position monitoring. The working principle, the experimental setup used, and the broadband performance of the DBC are presented.

  1. Anterior segment optical coherence tomography for the diagnosis of corneal dystrophies according to the IC3D classification.

    Science.gov (United States)

    Siebelmann, Sebastian; Scholz, Paula; Sonnenschein, Simon; Bachmann, Björn; Matthaei, Mario; Cursiefen, Claus; Heindl, Ludwig M

    2017-08-09

    Corneal dystrophies are categorized according to the International Committee for Classification of Corneal Dystrophies (IC3D) classification, and their treatment depends on the affected structures and layer of the cornea. Therefore, estimating the depth and extent of the morphological changes due to the specific dystrophy is crucial when deciding between different treatment options. Besides superficial laser treatments and penetrating keratoplasty, minimal invasive lamellar keratoplasties such as Descemet membrane endothelial keratoplasty, deep anterior lamellar keratoplasty, or Descemet stripping automated keratoplasty have become increasingly popular to exchange the specific opaque layers in dystrophic eyes. To determine the morphological changes of the cornea in the different dystrophies, in addition to slit-lamp examination, anterior segment optical coherence tomography has become an important tool with nearly histological resolution. Nonetheless, only a few case series describe the characteristics of changes seen on anterior segment optical coherence tomography. Therefore, we summarize anterior segment optical coherence tomography signs and correlate with slit-lamp examination, as well as the histopathological findings, of corneal dystrophies according to the IC3D classification. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Optical CT scanner for in-air readout of gels for external radiation beam 3D dosimetry.

    Science.gov (United States)

    Ramm, Daniel; Rutten, Thomas P; Shepherd, Justin; Bezak, Eva

    2012-06-21

    Optical CT scanners for a 3D readout of externally irradiated radiosensitive hydrogels currently require the use of a refractive index (RI) matching liquid bath to obtain suitable optical ray paths through the gel sample to the detector. The requirement for a RI matching liquid bath has been negated by the design of a plastic cylindrical gel container that provides parallel beam geometry through the gel sample for the majority of the projection. The design method can be used for various hydrogels. Preliminary test results for the prototype laser beam scanner with ferrous xylenol-orange gel show geometric distortion of 0.2 mm maximum, spatial resolution limited to beam spot size of about 0.4 mm and 0.8% noise (1 SD) for a uniform irradiation. Reconstruction of a star pattern irradiated through the cylinder walls demonstrates the suitability for external beam applications. The extremely simple and cost-effective construction of this optical CT scanner, together with the simplicity of scanning gel samples without RI matching fluid increases the feasibility of using 3D gel dosimetry for clinical external beam dose verifications.

  3. Differential axial contrast of optical sections: laser microtomography and quantitative 3D reconstruction

    Science.gov (United States)

    Pogorelova, M. A.; Golichenkov, V. A.; Pogorelov, A. G.

    2014-03-01

    Specific features of the quantitative laser microtomography of biological samples are discussed. The method exhibits the main advantages of a confocal microscope (rapid measurement of a stack of parallel optical cross sections and accurate displacement of an object along the optical axis). A relatively high contrast is reached owing to the superposition of pairwise complementary images on neighboring cross sections. A simple and convenient algorithm for image processing does not require additional software and can be computerized using a conventional graphic editor. The applicability of the method is illustrated using volume measurements of a single cell of an early mouse embryo.

  4. Investigation on a replica step gauge for optical 3D scanning of micro parts

    DEFF Research Database (Denmark)

    Cantatore, Angela; De Chiffre, Leonardo; Carmignato, S.

    2010-01-01

    . The stability over time of the step gauge was evaluated by repetitive measurement campaigns over a period of eight months, using measurements taken with a tactile CMM and with an optical scanner. Surface cooperativeness was investigated by measuring artefact grooves and pitch and comparing results with tactile......This work deals with investigation of the stability over time and surface cooperativeness of a calibration artefact intended for optical scanner verification. A replica step gauge with 11 grooves, made of bisacryl material for dental applications (luxabite) and previously fabricated was studied...

  5. Optically clearing tissue as an initial step for 3D imaging of core biopsies to diagnose pancreatic cancer

    Science.gov (United States)

    Das, Ronnie; Agrawal, Aishwarya; Upton, Melissa P.; Seibel, Eric J.

    2014-02-01

    The pancreas is a deeply seated organ requiring endoscopically, or radiologically guided biopsies for tissue diagnosis. Current approaches include either fine needle aspiration biopsy (FNA) for cytologic evaluation, or core needle biopsies (CBs), which comprise of tissue cores (L = 1-2 cm, D = 0.4-2.0 mm) for examination by brightfield microscopy. Between procurement and visualization, biospecimens must be processed, sectioned and mounted on glass slides for 2D visualization. Optical information about the native tissue state can be lost with each procedural step and a pathologist cannot appreciate 3D organization from 2D observations of tissue sections 1-8 μm in thickness. Therefore, how might histological disease assessment improve if entire, intact CBs could be imaged in both brightfield and 3D? CBs are mechanically delicate; therefore, a simple device was made to cut intact, simulated CBs (L = 1-2 cm, D = 0.2-0.8 mm) from porcine pancreas. After CBs were laid flat in a chamber, z-stack images at 20x and 40x were acquired through the sample with and without the application of an optical clearing agent (FocusClear®). Intensity of transmitted light increased by 5-15x and islet structures unique to pancreas were clearly visualized 250-300 μm beneath the tissue surface. CBs were then placed in index matching square capillary tubes filled with FocusClear® and a standard optical clearing agent. Brightfield z-stack images were then acquired to present 3D visualization of the CB to the pathologist.

  6. Bacteriorhodopsin: Tunable Optical Nonlinear Magnetic Response

    CERN Document Server

    Bovino, F A; Sibilia, C; Giardina, M; Váró, G; Gergely, C

    2011-01-01

    We report on a strong and tunable magnetic optical nonlinear response of Bacteriorhodopsin (BR) under "off resonance" femtosecond (fs) pulse excitation, by detecting the polarization map of the noncollinear second harmonic signal of an oriented BR film, as a function of the input beam power. BR is a light-driven proton pump with a unique photochemistry initiated by the all trans retinal chromophore embedded in the protein. An elegant application of this photonic molecular machine has been recently found in the new area of optogenetics, where genetic expression of BR in brain cells conferred a light responsivity to the cells enabling thus specific stimulation of neurons. The observed strong tunable magnetic nonlinear response of BR might trigger promising applications in the emerging area of pairing optogenetics and functional magnetic resonance imaging susceptible to provide an unprecedented complete functional mapping of neural circuits.

  7. Editorial: 3DIM-DS 2015: Optical image processing in the context of 3D imaging, metrology, and data security

    Science.gov (United States)

    Alfalou, Ayman

    2017-02-01

    Following the first International Symposium on 3D Imaging, Metrology, and Data Security (3DIM-DS) held in Shenzhen during september 2015, this special issue gathers a series of articles dealing with the main topics discussed during this symposium. These topics highlighted the importance of studying complex data treatment systems and intensive calculations designed for high dimensional imaging and metrology for which high image quality and high transmission speed become critical issues in a number of technological applications. A second purpose was to celebrate the International Year of Light by emphasizing the important role of optics in actual information processing systems.

  8. Metallo-dielectric core-shell nanospheres as building blocks for optical 3D isotropic negative-index metamaterials

    CERN Document Server

    Paniagua-Domínguez, R; Marqués, R

    2011-01-01

    We propose a fully 3D, isotropic metamaterial with strong electric and magnetic response in the optical regime, based on metal-dielectric core-shell nanospheres. The magnetic response stems from the lowest, magnetic-dipole resonance of the dielectric nanoshell with high refractive index. The magnetic resonance can be tuned to coincide with the plasmon resonance of the metal core, responsible for the electric response. Since the response does not stem from coupling between structures, no particular periodic arrangement needs to be imposed.

  9. Optical 3D laser measurement system for navigation of autonomous mobile robot

    Science.gov (United States)

    Básaca-Preciado, Luis C.; Sergiyenko, Oleg Yu.; Rodríguez-Quinonez, Julio C.; García, Xochitl; Tyrsa, Vera V.; Rivas-Lopez, Moises; Hernandez-Balbuena, Daniel; Mercorelli, Paolo; Podrygalo, Mikhail; Gurko, Alexander; Tabakova, Irina; Starostenko, Oleg

    2014-03-01

    In our current research, we are developing a practical autonomous mobile robot navigation system which is capable of performing obstacle avoiding task on an unknown environment. Therefore, in this paper, we propose a robot navigation system which works using a high accuracy localization scheme by dynamic triangulation. Our two main ideas are (1) integration of two principal systems, 3D laser scanning technical vision system (TVS) and mobile robot (MR) navigation system. (2) Novel MR navigation scheme, which allows benefiting from all advantages of precise triangulation localization of the obstacles, mostly over known camera oriented vision systems. For practical use, mobile robots are required to continue their tasks with safety and high accuracy on temporary occlusion condition. Presented in this work, prototype II of TVS is significantly improved over prototype I of our previous publications in the aspects of laser rays alignment, parasitic torque decrease and friction reduction of moving parts. The kinematic model of the MR used in this work is designed considering the optimal data acquisition from the TVS with the main goal of obtaining in real time, the necessary values for the kinematic model of the MR immediately during the calculation of obstacles based on the TVS data.

  10. Non-linear dynamic analyses of 3D masonry structures by means of a homogenized rigid body and spring model (HRBSM)

    Science.gov (United States)

    Bertolesi, Elisa; Milani, Gabriele; Casolo, Siro

    2016-12-01

    A simple homogenized rigid body and spring model (HRBSM) is presented and applied for the non-linear dynamic analysis of 3D masonry structures. The approach, previously developed by the authors for the modeling of in-plane loaded walls is herein extended to real 3D buildings subjected to in- and out-of-plane deformation modes. The elementary cell is discretized by means of three-noded plane stress elements and non-linear interfaces. At a structural level, the non-linear analyses are performed replacing the homogenized orthotropic continuum with a rigid element and non-linear spring assemblage (RBSM) by means of which both in and out of plane mechanisms are allowed. All the simulations here presented are performed using the commercial software Abaqus. In order to validate the proposed model for the analyses of full scale structures subjected to seismic actions, two different examples are critically discussed, namely a church façade and an in-scale masonry building, both subjected to dynamic excitation. The results obtained are compared with experimental or numerical results available in literature.

  11. Nonlinear Quantum Optics in Artificially Structured Media

    Science.gov (United States)

    Helt, Lukas Gordon

    This thesis presents an analysis of photon pairs generated via either spontaneous parametric downconversion or spontaneous four-wave mixing in channel waveguides as well as in microring resonators side-coupled to channel waveguides. The state of photons exiting a particular device is calculated within a general Hamiltonian formalism that simplifies the link between quantum nonlinear optics experiments and classical nonlinear optics experiments. This state contains information regarding photon pair production efficiency as well as modal and spectral correlations between the two photons, characterized by a two-dimensional spectral distribution function called the biphoton wave function. In the limit of a low probability of pair production, photon pair production efficiencies are cast into forms resembling corresponding well-known classical nonlinear optical frequency conversion efficiencies, making it easy to see what plays the role of a classical "seed" field in an un-seeded (quantum) process. This also allows photon pair production efficiencies to be calculated based on the results of classical nonlinear optical experiments. It is further calculated that, unless generated photons are collected over a very narrow frequency range, their generation efficiency does not scale the same way with device length in a channel waveguide, or resonance quality factor in a microring resonator, as might be expected from the corresponding classical frequency conversion efficiency. Although calculations do not include self- or cross-phase modulation, nor two-photon absorption or free-carrier absorption, it is calculated that their neglect is justified in the low pair production probability limit. Linear (scattering) loss is also neglected, though partially addressed in the final chapter of this thesis. Biphoton wave functions are calculated explicitly, such that their shape and orientation, including approximate analytic expressions for their widths, can easily be determined. This

  12. Nonlinear optical properties of induced transmission filters.

    Science.gov (United States)

    Owens, Daniel T; Fuentes-Hernandez, Canek; Hales, Joel M; Perry, Joseph W; Kippelen, Bernard

    2010-08-30

    The nonlinear optical (NLO) properties of induced transmission filters (ITFs) based on Ag are experimentally determined using white light continuum pump-probe measurements. The experimental results are supported using simulations based on the matrix transfer method. The magnitude of the NLO response is shown to be 30 times that of an isolated Ag film of comparable thickness. The impacts of design variations on the linear and NLO response are simulated. It is shown that the design can be modified to enhance the NLO response of an ITF by a factor of 2 or more over a perfectly matched ITF structure.

  13. Nonlinear Optics in AlGaAs on Insulator

    DEFF Research Database (Denmark)

    Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta;

    2016-01-01

    AlGaAs on insulator is a powerful nonlinear platform sporting a high effective nonlinearity and the possibility to fabricate complex designs. We will present low loss waveguides enabling efficient optical signal processing and Kerr comb generation.......AlGaAs on insulator is a powerful nonlinear platform sporting a high effective nonlinearity and the possibility to fabricate complex designs. We will present low loss waveguides enabling efficient optical signal processing and Kerr comb generation....

  14. Fast, background-free, 3D super-resolution optical fluctuation imaging (SOFI).

    Science.gov (United States)

    Dertinger, T; Colyer, R; Iyer, G; Weiss, S; Enderlein, J

    2009-12-29

    Super-resolution optical microscopy is a rapidly evolving area of fluorescence microscopy with a tremendous potential for impacting many fields of science. Several super-resolution methods have been developed over the last decade, all capable of overcoming the fundamental diffraction limit of light. We present here an approach for obtaining subdiffraction limit optical resolution in all three dimensions. This method relies on higher-order statistical analysis of temporal fluctuations (caused by fluorescence blinking/intermittency) recorded in a sequence of images (movie). We demonstrate a 5-fold improvement in spatial resolution by using a conventional wide-field microscope. This resolution enhancement is achieved in iterative discrete steps, which in turn allows the evaluation of images at different resolution levels. Even at the lowest level of resolution enhancement, our method features significant background reduction and thus contrast enhancement and is demonstrated on quantum dot-labeled microtubules of fibroblast cells.

  15. Depth-resolved 3D visualization of coronary microvasculature with optical microangiography

    Science.gov (United States)

    Qin, Wan; Roberts, Meredith A.; Qi, Xiaoli; Murry, Charles E.; Zheng, Ying; Wang, Ruikang K.

    2016-11-01

    In this study, we propose a novel implementation of optical coherence tomography-based angiography combined with ex vivo perfusion of fixed hearts to visualize coronary microvascular structure and function. The extracorporeal perfusion of Intralipid solution allows depth-resolved angiographic imaging, control of perfusion pressure, and high-resolution optical microangiography. The imaging technique offers new opportunities for microcirculation research in the heart, which has been challenging due to motion artifacts and the lack of independent control of pressure and flow. With the ability to precisely quantify structural and functional features, this imaging platform has broad potential for the study of the pathophysiology of microvasculature in the heart as well as other organs.

  16. Omnidirectional 3D nanoplasmonic optical antenna array via soft-matter transformation.

    Science.gov (United States)

    Ross, Benjamin M; Wu, Liz Y; Lee, Luke P

    2011-07-13

    Inspired by the natural processes during morphogenesis, we demonstrate the transformation capability of active soft-matter to define nanoscale metal-on-polymer architectures below the resolution limit of conventional lithography. Specifically, using active polymers, we fabricate and characterize ultradense nanoplasmonic antenna arrays with sub-10 nm tip-to-tip nanogaps. In addition, the macroscale morphology can be independently manipulated into arbitrary three-dimensional geometries, demonstrated with the fabrication of an omnidirectional nanoplasmonic optical antenna array.

  17. Adaptive Optics Assisted 3D spectroscopy observations for black hole mass measurements

    OpenAIRE

    Pastorini, Guia

    2006-01-01

    The very high spatial resolution provided by Adaptive Optics assisted spectroscopic observations at 8m-class telescopes (e.g. with SINFONI at the VLT) will allow to greatly increase the number of direct black hole (BH) mass measurements which is currently very small. This is a fundamental step to investigate the tight link between galaxy evolution and BH growth, revealed by the existing scaling relations between $M_{BH}$ and galaxy structural parameters. I present preliminary results from SIN...

  18. Linear and nonlinear MHD mode coupling of the fast magnetoacoustic wave about a 3D magnetic null point

    CERN Document Server

    Thurgood, J O; 10.1051/0004-6361/201219850

    2012-01-01

    Context: Coronal magnetic null points have been implicated as possible locations for localised heating events in 2D models. We investigate this possibility about fully 3D null points. Aims: We investigate the nature of the fast magnetoacoustic wave about a fully 3D magnetic null point, with a specific interest in its propagation, and we look for evidence of MHD mode coupling and/or conversion to the Alfv\\'en mode. Methods: A special fieldline and flux-based coordinate system was constructed to permit the introduction of a pure fast magnetoacoustic wave in the vicinity of proper and improper 3D null points. We considered the ideal, {\\beta} = 0, MHD equations, which are solved using the LARE3D numerical code. The constituent modes of the resulting wave were isolated and identified using the special coordinate system. Numerical results were supported by analytical work derived from perturbation theory and a linear implementation of the WKB method. Results: An initially pure fast wave is found to be permanently d...

  19. Nonlinear 3-D Microwave Imaging for Breast-Cancer Screening: Log, Phase, and Log-Phase Formulation

    DEFF Research Database (Denmark)

    Jensen, Peter Damsgaard; Rubæk, Tonny; Mohr, Johan Jacob;

    2011-01-01

    The imaging algorithm used in the 3-D microwave imaging system for breast cancer screening, currently being developed at the Technical University of Denmark, is based on an iterative Newton-type algorithm. In this algorithm, the distribution of the electromagnetic constitutive parameters is updat...

  20. 3D laser inspection of fuel assembly grid spacers for nuclear reactors based on diffractive optical elements

    Science.gov (United States)

    Finogenov, L. V.; Lemeshko, Yu A.; Zav'yalov, P. S.; Chugui, Yu V.

    2007-06-01

    Ensuring the safety and high operation reliability of nuclear reactors takes 100% inspection of geometrical parameters of fuel assemblies, which include the grid spacers performed as a cellular structure with fuel elements. The required grid spacer geometry of assembly in the transverse and longitudinal cross sections is extremely important for maintaining the necessary heat regime. A universal method for 3D grid spacer inspection using a diffractive optical element (DOE), which generates as the structural illumination a multiple-ring pattern on the inner surface of a grid spacer cell, is investigated. Using some DOEs one can inspect the nomenclature of all produced grids. A special objective has been developed for forming the inner surface cell image. The problems of diffractive elements synthesis, projecting optics calculation, adjusting methods as well as calibration of the experimental measuring system are considered. The algorithms for image processing for different constructive elements of grids (cell, channel hole, outer grid spacer rim) and the experimental results are presented.

  1. GPS/Optical/Inertial Integration for 3D Navigation Using Multi-Copter Platforms

    Science.gov (United States)

    Dill, Evan T.; Young, Steven D.; Uijt De Haag, Maarten

    2017-01-01

    In concert with the continued advancement of a UAS traffic management system (UTM), the proposed uses of autonomous unmanned aerial systems (UAS) have become more prevalent in both the public and private sectors. To facilitate this anticipated growth, a reliable three-dimensional (3D) positioning, navigation, and mapping (PNM) capability will be required to enable operation of these platforms in challenging environments where global navigation satellite systems (GNSS) may not be available continuously. Especially, when the platform's mission requires maneuvering through different and difficult environments like outdoor opensky, outdoor under foliage, outdoor-urban and indoor, and may include transitions between these environments. There may not be a single method to solve the PNM problem for all environments. The research presented in this paper is a subset of a broader research effort, described in [1]. The research is focused on combining data from dissimilar sensor technologies to create an integrated navigation and mapping method that can enable reliable operation in both an outdoor and structured indoor environment. The integrated navigation and mapping design is utilizes a Global Positioning System (GPS) receiver, an Inertial Measurement Unit (IMU), a monocular digital camera, and three short to medium range laser scanners. This paper describes specifically the techniques necessary to effectively integrate the monocular camera data within the established mechanization. To evaluate the developed algorithms a hexacopter was built, equipped with the discussed sensors, and both hand-carried and flown through representative environments. This paper highlights the effect that the monocular camera has on the aforementioned sensor integration scheme's reliability, accuracy and availability.

  2. Coherent addressing of individual neutral atoms in a 3D optical lattice

    CERN Document Server

    Wang, Yang; Corcovilos, Theodore A; Kumar, Aishwarya; Weiss, David S

    2015-01-01

    We demonstrate arbitrary coherent addressing of individual neutral atoms in a $5\\times 5\\times 5$ array formed by an optical lattice. Addressing is accomplished using rapidly reconfigurable crossed laser beams to selectively ac Stark shift target atoms, so that only target atoms are resonant with state-changing microwaves. The effect of these targeted single qubit gates on the quantum information stored in non-targeted atoms is smaller than $3\\times 10^{-3}$ in state fidelity. This is an important step along the path of converting the scalability promise of neutral atoms into reality.

  3. Coherent Addressing of Individual Neutral Atoms in a 3D Optical Lattice.

    Science.gov (United States)

    Wang, Yang; Zhang, Xianli; Corcovilos, Theodore A; Kumar, Aishwarya; Weiss, David S

    2015-07-24

    We demonstrate arbitrary coherent addressing of individual neutral atoms in a 5×5×5 array formed by an optical lattice. Addressing is accomplished using rapidly reconfigurable crossed laser beams to selectively ac Stark shift target atoms, so that only target atoms are resonant with state-changing microwaves. The effect of these targeted single qubit gates on the quantum information stored in nontargeted atoms is smaller than 3×10^{-3} in state fidelity. This is an important step along the path of converting the scalability promise of neutral atoms into reality.

  4. Data Assimilation of Lightning using 1D+3D/4D WRF Var Assimilation Schemes with Non-Linear Observation Operators

    Science.gov (United States)

    Navon, M. I.; Stefanescu, R.; Fuelberg, H. E.; Marchand, M.

    2012-12-01

    NASA's launch of the GOES-R Lightning Mapper (GLM) in 2015 will provide continuous, full disc, high resolution total lightning (IC + CG) data. The data will be available at a horizontal resolution of approximately 9 km. Compared to other types of data, the assimilation of lightning data into operational numerical models has received relatively little attention. Previous efforts of lightning assimilation mostly have employed nudging. This paper will describe the implementation of 1D+3D/4D Var assimilation schemes of existing ground-based WTLN (Worldwide Total Lightning Network) lightning observations using non-linear observation operators in the incremental WRFDA system. To mimic the expected output of GLM, the WTLN data were used to generate lightning super-observations characterized by flash rates/81 km2/20 min. A major difficulty associated with variational approaches is the complexity of the observation operator that defines the model equivalent of lightning. We use Convective Available Potential Energy (CAPE) as a proxy between lightning data and model variables. This operator is highly nonlinear. Marecal and Mahfouf (2003) have shown that nonlinearities can prevent direct assimilation of rainfall rates in the ECMWF 4D-VAR (using the incremental formulation proposed by Courtier et al. (1994)) from being successful. Using data from the 2011 Tuscaloosa, AL tornado outbreak, we have proved that the direct assimilation of lightning data into the WRF 3D/4D - Var systems is limited due to this incremental approach. Severe threshold limits must be imposed on the innovation vectors to obtain an improved analysis. We have implemented 1D+3D/4D Var schemes to assimilate lightning observations into the WRF model. Their use avoids innovation vector constrains from preventing the inclusion of a greater number of lightning observations Their use also minimizes the problem that nonlinearities in the moist convective scheme can introduce discontinuities in the cost function

  5. Enhanced Kerr electro-optic nonlinearity through cascaded Pockels effects

    CERN Document Server

    Li, Guang-Zhen; Jiang, Hao-Wei; Chen, Xian-Feng

    2015-01-01

    We demonstrated a large enhancement of Kerr electro-optic nonlinearity through cascaded Pockels effects in a domain inversion ferroelectric crystal. We designed a structure that can implement the cascaded Pockels effects and second-harmonic generation simultaneously. The energy coupling between the fundamental lights of different polarizations led to a large nonlinear phase shift, and thus an effective electro-optic nonlinear refractive index. The effective nonlinearity can be either positive or negative, causing the second-harmonic spectra to move towards the coupling center, which in turn, offered us a way to measure the effective electro-optic nonlinear refractive index. The corresponding enhanced Kerr electro-optic nonlinearity is more than three orders of magnitude higher than the intrinsic value. These results open a door to manipulate the nonlinear phase by applying external electric field instead of light intensity in noncentrosymmetric crystals.

  6. Full 3D translational and rotational optical control of multiple rod-shaped bacteria.

    Science.gov (United States)

    Hörner, Florian; Woerdemann, Mike; Müller, Stephanie; Maier, Berenike; Denz, Cornelia

    2010-07-01

    The class of rod-shaped bacteria is an important example of non-spherical objects where defined alignment is desired for the observation of intracellular processes or studies of the flagella. However, all available methods for orientational control of rod-shaped bacteria are either limited with respect to the accessible rotational axes or feasible angles or restricted to one single bacterium. In this paper we demonstrate a scheme to orientate rod-shaped bacteria with holographic optical tweezers (HOT) in any direction. While these bacteria have a strong preference to align along the direction of the incident laser beam, our scheme provides for the first time full rotational control of multiple bacteria with respect to any arbitrary axis. In combination with the translational control HOT inherently provide, this enables full control of all three translational and the two important rotational degrees of freedom of multiple rod-shaped bacteria and allows one to arrange them in any desired configuration.

  7. Optical non-invasive 3D characterization of pottery of pre-colonial Paranaiba valley tribes

    Science.gov (United States)

    Magalhães, Wagner; Alves, Márcia Angelina; Costa, Manuel F.

    2014-08-01

    Optical non-invasive inspection tools and methods had expensively proven, for several decades now, their invaluable importance in the preservation of cultural heritage and artwork. In this paper we will report on an optical non-invasive microtopographic characterization work on pre-historical and pre-colonial ceramics and pottery of tribes in the Paranaiba valley in Minas Gerais, Brazil. The samples object of this work were collected at the Inhazinha archeological site (19º 10'00" S / 47° 11'00" W) in the vicinity of Perdizes municipality in transition between the West mining area and the "triangle" area in the center of Brazil. It is a hilly region (850m high) traversed by a number of rivers and streams tributary of Araguari river like Quebra Anzol river and Macaúba and Olegário streams. The Inhazinha site' excavations are part of the Project Jigsaw Hook which since 1980 aimed the establishment of a chrono-cultural framework associated with the study of the socio-cultural dynamics corresponding to successive occupations of hunter-recollector-farmer' tribes in prehistoric and pre-colonial times in the Paranaíba valley in Minas Gerais, Brazil. Two groups of indigenous Indian occupations were found. Both of the pre-colonial period dated at 1,095 ± 186 years ago (TL-FATEC/SP for Zone 1) and of the early nineteenth century dated at 212 ± 19 years ago (EMS-CENA-USP/SP) and 190 ± 30 years ago (C14- BETA/USA) in Zone 2 seemingly occupied by southern Kayapós tribes. The pottery found is decorated with incisions with different geometric distributions and levels of complexity.

  8. 3-D nonlinear dynamic progressive collapse analysis of multi-storey steel composite frame buildings—Parametric study

    OpenAIRE

    Fu, F.

    2010-01-01

    A 3-dimensional finite element model built by the author was used in this paper to analyze the progressive collapse of a multi-storey steel composite frame building. The proposed model can represent the global 3-D behavior of the multi-storey building under the sudden column removal scenarios. Based on this model, parametric studies were carried out to investigate the structural behavior with variations in: strength of structural steel, strength of concrete and reinforcement mesh size. Throug...

  9. Toward acquiring comprehensive radiosurgery field commissioning data using the PRESAGE/optical-CT 3D dosimetry system

    Energy Technology Data Exchange (ETDEWEB)

    Clift, Corey; Thomas, Andrew; Chang Zheng; Oldham, Mark [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States); Adamovics, John [Department of Chemistry, Rider University, Lawrenceville, NJ 08648 (United States); Das, Indra [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States)], E-mail: cclift@montefiore.org

    2010-03-07

    Achieving accurate small field dosimetry is challenging. This study investigates the utility of a radiochromic plastic PRESAGE read with optical-CT for the acquisition of radiosurgery field commissioning data from a Novalis Tx system with a high-definition multileaf collimator (HDMLC). Total scatter factors (S{sub c,p}), beam profiles, and penumbrae were measured for five different radiosurgery fields (5, 10, 20, 30 and 40 mm) using a commercially available optical-CT scanner (OCTOPUS, MGS Research). The percent depth dose (PDD), beam profile and penumbra of the 10 mm field were also measured using a higher resolution in-house prototype CCD-based scanner. Gafchromic EBT film was used for independent verification. Measurements of S{sub c,p} made with PRESAGE and film agreed with mini-ion chamber commissioning data to within 4% for every field (range 0.2-3.6% for PRESAGE, and 1.6-3.6% for EBT). PDD, beam profile and penumbra measurements made with the two PRESAGE/optical-CT systems and film showed good agreement with the high-resolution diode commissioning measurements with a competitive resolution (0.5 mm pixels). The in-house prototype optical-CT scanner allowed much finer resolution compared with previous applications of PRESAGE. The advantages of the PRESAGE (registered) system for small field dosimetry include 3D measurements, negligible volume averaging, directional insensitivity, an absence of beam perturbations, energy and dose rate independence.

  10. High-resolution 3-D imaging of surface damage sites in fused silica with Optical Coherence Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Guss, G; Bass, I; Hackel, R; Mailhiot, C; Demos, S G

    2007-10-30

    In this work, we present the first successful demonstration of a non-contact technique to precisely measure the 3D spatial characteristics of laser induced surface damage sites in fused silica for large aperture laser systems by employing Optical Coherence Tomography (OCT). What makes OCT particularly interesting in the characterization of optical materials for large aperture laser systems is that its axial resolution can be maintained with working distances greater than 5 cm, whether viewing through air or through the bulk of thick optics. Specifically, when mitigating surface damage sites against further growth by CO{sub 2} laser evaporation of the damage, it is important to know the depth of subsurface cracks below the damage site. These cracks are typically obscured by the damage rubble when imaged from above the surface. The results to date clearly demonstrate that OCT is a unique and valuable tool for characterizing damage sites before and after the mitigation process. We also demonstrated its utility as an in-situ diagnostic to guide and optimize our process when mitigating surface damage sites on large, high-value optics.

  11. Design and Evaluation of a Fiber-Optic Grip Force Sensor with Compliant 3D-Printable Structure for (fMRI Applications

    Directory of Open Access Journals (Sweden)

    Tobias L. Bützer

    2016-01-01

    Full Text Available Grip force sensors compatible with magnetic resonance imaging (MRI are used in human motor control and decision-making research, providing objective and sensitive behavioral outcome measures. Commercial sensors are expensive, cover limited force ranges, rely on pneumatic force transmission that cannot detect fast force changes, or are electrically active, which increases the risk of electromagnetic interference. We present the design and evaluation of a low-cost, 3D-printed, inherently MRI-compatible grip force sensor based on a commercial intensity-based fiber-optic sensor. A compliant monobloc structure with flexible hinges transduces grip force to a linear displacement captured by the fiber-optic sensor. The structure can easily be adapted for different force ranges by changing the hinge thickness. A prototype designed for forces up to 800 N was manufactured and showed a highly linear behavior (nonlinearity of 2.37% and an accuracy of 1.57% in a range between zero and 500 N. It can be printed and assembled within one day and for less than $300. Accurate performance was confirmed, both inside and outside a 3 T MRI scanner within a pilot study. Given its simple design allowing for customization of sensing properties and ergonomics for different applications and requirements, the proposed grip force handle offers researchers a valuable scientific tool.

  12. Highly nonlinear optical regime in graphene-assisted cavities: lasing threshold bares graphene nonlinearity

    CERN Document Server

    Ciattoni, Alessandro

    2014-01-01

    Strong nonlinear optical mechanisms operating in a miniaturized environment have a key role in photonics since they allow complex and versatile light manipulation within subwavelength devices. On the other hand, due to its two-dimensional planar geometry, graphene can easily be embedded within miniaturized structures and has fascinating linear and nonlinear optical properties arising from its relativistic electron dynamics. However, very few light steering graphene-based setups with a strong nonlinear behavior have been proposed since, due to its intrinsic planar localization, graphene nonlinearity has to be exploited through novel schemes not available in standard bulk nonlinear optics. Here we show that an active cavity hosting a graphene sheet, when tuned near its lasing threshold, is able to isolate the spatially localized graphene nonlinearity thus producing a very strong nonlinear device response with multi-valued features. The proposed strategy for exploiting graphene nonlinearity through its baring co...

  13. Quality assessment of reverse engineering process based on full-field true-3D optical measurements

    Science.gov (United States)

    Kujawinska, Malgorzata; Sitnik, Robert

    2000-08-01

    In the paper the sequential steps of reverse engineering based on the data gathered by full-field optical system are discussed. Each step is concerned from the point of view of its influence on the final quality of the shape of manufactured object. At first the modern shape measurement system based on the combination of fringe projection, Grey code and experimental calibration is presented. The system enables the determination of absolute coordinates of the object measured from many directions. The dependence of the quality of the cloud of points on the type of object and the measurement procedure is discussed. Then the methods of transferring the experimental data into CAD/CAM/CAE system are presented. The quality of the virtual object in the form of closed triangular mesh is analyzed. Basing on this virtual object the copy of initial body is produced and measured. The accuracy of the object manufactured is determined and the main sources of errors are discussed. The modifications of the system and algorithms that minimize the errors are proposed. The reverse engineering sequence is presented is illustrated by several examples.

  14. Adaptive Optics Assisted 3D spectroscopy observations for black hole mass measurements

    CERN Document Server

    Pastorini, G

    2006-01-01

    The very high spatial resolution provided by Adaptive Optics assisted spectroscopic observations at 8m-class telescopes (e.g. with SINFONI at the VLT) will allow to greatly increase the number of direct black hole (BH) mass measurements which is currently very small. This is a fundamental step to investigate the tight link between galaxy evolution and BH growth, revealed by the existing scaling relations between $M_{BH}$ and galaxy structural parameters. I present preliminary results from SINFONI K-band spectroscopic observations of a sample of 5 objects with $M_{BH}$ measurements obtained with the Reverberation Mapping (RM) technique. This technique is the starting point to derive the so-called virial $M_{BH}$ estimates, currently the only way to measure $M_{BH}$ at high redshift. Our goal is to assess the reliability of RM by measuring $M_{BH}$ with both gas and stellar kinematical methods and to investigate whether active galaxies follow the same $M_{BH}$-galaxy correlations as normal ones.

  15. ELTs Adaptive Optics for Multi-Objects 3D Spectroscopy Key Parameters and Design Rules

    CERN Document Server

    Neichel, B; Fusco, T; Gendron, E; Puech, M; Rousset, G; Hammer, F

    2006-01-01

    In the last few years, new Adaptive Optics [AO] techniques have emerged to answer new astronomical challenges: Ground-Layer AO [GLAO] and Multi-Conjugate AO [MCAO] to access a wider Field of View [FoV], Multi-Object AO [MOAO] for the simultaneous observation of several faint galaxies, eXtreme AO [XAO] for the detection of faint companions. In this paper, we focus our study to one of these applications : high red-shift galaxy observations using MOAO techniques in the framework of Extremely Large Telescopes [ELTs]. We present the high-level specifications of a dedicated instrument. We choose to describe the scientific requirements with the following criteria : 40% of Ensquared Energy [EE] in H band (1.65um) and in an aperture size from 25 to 150 mas. Considering these specifications we investigate different AO solutions thanks to Fourier based simulations. Sky Coverage [SC] is computed for Natural and Laser Guide Stars [NGS, LGS] systems. We show that specifications are met for NGS-based systems at the cost of ...

  16. 3D printed broadband transformation optics based all-dielectric microwave lenses

    Science.gov (United States)

    Yi, Jianjia; Nawaz Burokur, Shah; Piau, Gérard-Pascal; de Lustrac, André

    2016-04-01

    Quasi-conformal transformation optics is applied to design electromagnetic devices for focusing and collimating applications at microwave frequencies. Two devices are studied and conceived by solving Laplace’s equation that describes the deformation of a medium in a space transformation. As validation examples, material parameters of two different lenses are derived from the analytical solutions of Laplace’s equation. The first lens is applied to produce an overall directive in-phase emission from an array of sources conformed on a cylindrical structure. The second lens allows deflecting a directive beam to an off-normal direction. Full-wave simulations are performed to verify the functionality of the calculated lenses. Prototypes presenting a graded refractive index are fabricated through three-dimensional polyjet printing using solely dielectric materials. Experimental measurements carried out show very good agreement with numerical simulations, thereby validating the proposed lenses. Such easily realizable designs open the way to low-cost all-dielectric microwave lenses for beam forming and collimation.

  17. 3D optical imagery for motion compensation in a limb ultrasound system

    Science.gov (United States)

    Ranger, Bryan J.; Feigin, Micha; Zhang, Xiang; Mireault, Al; Raskar, Ramesh; Herr, Hugh M.; Anthony, Brian W.

    2016-04-01

    Conventional processes for prosthetic socket fabrication are heavily subjective, often resulting in an interface to the human body that is neither comfortable nor completely functional. With nearly 100% of amputees reporting that they experience discomfort with the wearing of their prosthetic limb, designing an effective interface to the body can significantly affect quality of life and future health outcomes. Active research in medical imaging and biomechanical tissue modeling of residual limbs has led to significant advances in computer aided prosthetic socket design, demonstrating an interest in moving toward more quantifiable processes that are still patient-specific. In our work, medical ultrasonography is being pursued to acquire data that may quantify and improve the design process and fabrication of prosthetic sockets while greatly reducing cost compared to an MRI-based framework. This paper presents a prototype limb imaging system that uses a medical ultrasound probe, mounted to a mechanical positioning system and submerged in a water bath. The limb imaging is combined with three-dimensional optical imaging for motion compensation. Images are collected circumferentially around the limb and combined into cross-sectional axial image slices, resulting in a compound image that shows tissue distributions and anatomical boundaries similar to magnetic resonance imaging. In this paper we provide a progress update on our system development, along with preliminary results as we move toward full volumetric imaging of residual limbs for prosthetic socket design. This demonstrates a novel multi-modal approach to residual limb imaging.

  18. Digital Holography and 3D Imaging: introduction to the joint feature issue in Applied Optics and Journal of the Optical Society of America B.

    Science.gov (United States)

    Banerjee, Partha P; Osten, Wolfgang; Picart, Pascal; Cao, Liangcai; Nehmetallah, George

    2017-05-01

    The OSA Topical Meeting on Digital Holography and 3D Imaging (DH) was held 25-28 July 2016 in Heidelberg, Germany, as part of the Imaging Congress. Feature issues based on the DH meeting series have been released by Applied Optics (AO) since 2007. This year, AO and the Journal of the Optical Society of America B (JOSA B) jointly decided to have one such feature issue in each journal. This feature issue includes 31 papers in AO and 11 in JOSA B, and covers a large range of topics, reflecting the rapidly expanding techniques and applications of digital holography and 3D imaging. The upcoming DH meeting (DH 2017) will be held from 29 May to 1 June in Jeju Island, South Korea.

  19. A scalable nonlinear fluid-structure interaction solver based on a Schwarz preconditioner with isogeometric unstructured coarse spaces in 3D

    Science.gov (United States)

    Kong, Fande; Cai, Xiao-Chuan

    2017-07-01

    Nonlinear fluid-structure interaction (FSI) problems on unstructured meshes in 3D appear in many applications in science and engineering, such as vibration analysis of aircrafts and patient-specific diagnosis of cardiovascular diseases. In this work, we develop a highly scalable, parallel algorithmic and software framework for FSI problems consisting of a nonlinear fluid system and a nonlinear solid system, that are coupled monolithically. The FSI system is discretized by a stabilized finite element method in space and a fully implicit backward difference scheme in time. To solve the large, sparse system of nonlinear algebraic equations at each time step, we propose an inexact Newton-Krylov method together with a multilevel, smoothed Schwarz preconditioner with isogeometric coarse meshes generated by a geometry preserving coarsening algorithm. Here ;geometry; includes the boundary of the computational domain and the wet interface between the fluid and the solid. We show numerically that the proposed algorithm and implementation are highly scalable in terms of the number of linear and nonlinear iterations and the total compute time on a supercomputer with more than 10,000 processor cores for several problems with hundreds of millions of unknowns.

  20. Integration of an optical fiber taper with an optical microresonator fabricated in glass by femtosecond laser 3D micromachining

    CERN Document Server

    Song, Jiangxin; Tang, Jialei; Qiao, Lingling; Cheng, Ya

    2014-01-01

    We report on fabrication of a microtoroid resonator of a high-quality factor (i. e., Q-factor of ~3.24x10^6 measured under the critical coupling condition) using femtosecond laser three-dimensional (3D) micromachining. Coupling of light into and out of the microresonator has been realized with a fiber taper that is reliably assembled with the microtoroid. The assembly of the fiber taper to the microtoroid is achieved by welding the fiber taper onto the sidewall of the microtoroid using CO2 laser irradiation. The integrated microresonator maintains a high Q-factor of 3.21x10^5 as measured in air.

  1. Integrated optic devices based on nonlinear optical polymers

    Science.gov (United States)

    van Tomme, Emmanuel; van Daele, Peter P.; Baets, Roel G.; Lagasse, Paul E.

    1991-03-01

    An examination is made of the state of the art of nonlinear optical polymeric materials in view of their potential advantages. It is shown that these organic materials have many attractive features compared to LiNbO3 and III-V semiconductors with regard to their use in integrated optic circuits, especially since the level of integration is ever increasing. Considering more specifically electro-optic devices, a description is given of some of the theoretical background and basic properties. These polymers have already demonstrated a very high and extremely fast electro-optic effect compared to LiNbO3. It is also shown how low-loss waveguides can be fabricated by using easy techniques such as direct UV bleaching. The performance of phase modulators, Mach-Zehnder interferometers, and 2 x 2 space switches built with such polymers is already very promising. The results described in this study indicate a rapid rate of progress made by this technology, and one can expect that polymers in general and NLO polymers in particular will play an increasingly important role in integrated optics.

  2. Measurement of Choroidal Thickness in Normal Eyes Using 3D OCT-1000 Spectral Domain Optical Coherence Tomography

    Science.gov (United States)

    Shin, Joong Won; Shin, Yong Un; Cho, Hee Yoon

    2012-01-01

    Purpose To study choroidal thickness and its topographic profile in normal eyes using 3D OCT-1000 spectral domain optical coherence tomography and the correlation with age and refractive error. Methods Fifty-seven eyes (45 individuals) with no visual complaints or ocular disease underwent horizontal and vertical line scanning using 3D OCT-1000. The definition of choroidal thickness was the vertical distance between the posterior edge of the hyper-reflective retinal pigment epithelium and the choroid/sclera junction. Choroidal thickness was measured in the subfoveal area at 500 µm intervals from the fovea to 2,500 µm in the nasal, temporal, superior, and inferior regions. The spherical equivalent refractive error was measured by autorefractometry. Statistical analysis was used to confirm the correlations of choroidal thickness with age and refraction error. Results The mean age of the 45 participants (57 eyes) was 45.28 years. Detailed visualization of the choroid for measuring its thickness was possible in 63.3% of eyes. The mean subfoveal choroidal thickness was found to be 270.8 µm (standard deviation [SD], ±51 µm), in horizontal scanning and 275.0 µm (SD, ±49 µm) in vertical scanning. The temporal choroidal thickness was greater than any 500 µm interval in corresponding locations, and there was no significant difference between the superior and inferior choroid as far as 2,000 µm from the fovea. Age and refractive error were associated with subfoveal choroidal thickness in terms of regression (p Choroidal thickness in normal Korean eyes can be measured using 3D OCT-1000 with high resolution line scanning. The topographical profile of choroidal thickness varies depending on its location. Age and refractive error are essential factors for interpretation of choroidal thickness. PMID:22870023

  3. 3D characterization of EMT cell density in developing cardiac cushions using optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Yu, Siyao; Gu, Shi; Zhao, Xiaowei; Liu, Yehe; Jenkins, Michael W.; Watanabe, Michiko; Rollins, Andrew M.

    2017-02-01

    Congenital heart defects (CHDs) are the most common birth defect, affecting between 4 and 75 per 1,000 live births depending on the inclusion criteria. Many of these defects can be traced to defects of cardiac cushions, critical structures during development that serve as precursors to many structures in the mature heart, including the atrial and ventricular septa, and all four sets of cardiac valves. Epithelial-mesenchymal transition (EMT) is the process through which cardiac cushions become populated with cells. Altered cushion size or altered cushion cell density has been linked to many forms of CHDs, however, quantitation of cell density in the complex 3D cushion structure poses a significant challenge to conventional histology. Optical coherence tomography (OCT) is a technique capable of 3D imaging of the developing heart, but typically lacks the resolution to differentiate individual cells. Our goal is to develop an algorithm to quantitatively characterize the density of cells in the developing cushion using 3D OCT imaging. First, in a heart volume, the atrioventricular (AV) cushions were manually segmented. Next, all voxel values in the region of interest were pooled together to generate a histogram. Finally, two populations of voxels were classified using either K-means classification, or a Gaussian mixture model (GMM). The voxel population with higher values represents cells in the cushion. To test the algorithm, we imaged and evaluated avian embryonic hearts at looping stages. As expected, our result suggested that the cell density increases with developmental stages. We validated the technique against scoring by expert readers.

  4. Reverse engineering of B-pillar with 3D optical scanning for manufacturing of non-uniform thickness part

    Directory of Open Access Journals (Sweden)

    Islam Md. Tasbirul

    2017-01-01

    Full Text Available This paper presents reverse engineering (RE of a complex automobile structural part, B-pillar. As a major part of the automobile body-in white (BiW, B-pillar has substantial opportunity for weight reduction by introducing variable thickness across its sections. To leverage such potential, an existing B-pillar was reverse engineered with a 3D optical scanner and computer aided design (CAD application. First, digital data (i.e. in meshes of exiting B-pillar was obtained by the scanner, and subsequently, this information was utilized in developing a complete 3D CAD model. CATIA V5 was used in the modeling where some of the essential work benches were “Digitized Shape Editor”, “Quick Surface Reconstruction”, “Wireframe and Surface Design”, “Freestyle”, “Generation Shape Design” and “Part design”. In the final CAD design, five different thicknesses were incorporated successfully in order to get a B-pillar with non-uniform sections. This research opened opportunities for thickness optimization and mold tooling design in real time manufacturing.

  5. Large nonlocal nonlinear optical response of castor oil

    Science.gov (United States)

    Souza, Rogério F.; Alencar, Márcio A. R. C.; Meneghetti, Mario R.; Hickmann, Jandir M.

    2009-09-01

    The nonlocal nonlinearity of castor oil was investigated using the Z-scan technique in the CW regime at 514 nm and in femtosecond regime at 810 nm. Large negative nonlinear refractive indexes of thermal origin, thermo-optical coefficients and degree of nonlocality were obtained for both laser excitation wavelengths. The results indicate that the electronic part of the nonlinear refractive index and nonlinear absorption were negligible. Our results suggest that castor oil is promising candidate as a nonlinear medium for several nonlocal optical applications, such as in spatial soliton propagation, as well as a dispersant agent in the measurement of absorptive properties of nanoparticles.

  6. Optical bistability in nonlinear composites with coated ellipsoidal nanoparticles

    CERN Document Server

    Pinchuk, A

    2003-01-01

    Nonlinear composite structures show great promise for use in optical switching, signal processing, etc. We derive an effective nonlinear dielectric permittivity of composite structures where coated ellipsoidal nonlinear particles are imbedded in a linear host medium. The derived expression for the effective dielectric permittivity tensor follows the Clasius-Mossotti approximation. We observe conditions for the existence of the optical bistability effect in a coated ellipsoidal particle with a nonlinear core and a metallic shell. Our numerical results show stronger bistability effects in more dense suspensions of nonlinear heterogeneous ellipsoids.

  7. Mechanical Characterization and Shape Optimization of Fascicle-Like 3D Skeletal Muscle Tissues Contracted with Electrical and Optical Stimuli.

    Science.gov (United States)

    Neal, Devin; Sakar, Mahmut Selman; Bashir, Rashid; Chan, Vincent; Asada, Haruhiko Harry

    2015-06-01

    In this study, we present a quantitative approach to construct effective 3D muscle tissues through shape optimization and load impedance matching with electrical and optical stimulation. We have constructed long, thin, fascicle-like skeletal muscle tissue and optimized its form factor through mechanical characterization. A new apparatus was designed and built, which allowed us to measure force-displacement characteristics with diverse load stiffnesses. We have found that (1) there is an optimal form factor that maximizes the muscle stress, (2) the energy transmitted to the load can be maximized with matched load stiffness, and (3) optical stimulation using channelrhodopsin2 in the muscle tissue can generate a twitch force as large as its electrical counterpart for well-developed muscle tissue. Using our tissue construct method, we found that an optimal initial diameter of 500 μm outperformed tissues using 250 μm by more than 60% and tissues using 760 μm by 105%. Using optimal load stiffness, our tissues have generated 12 pJ of energy per twitch at a peak generated stress of 1.28 kPa. Additionally, the difference in optically stimulated twitch performance versus electrically stimulated is a function of how well the overall tissue performs, with average or better performing strips having less than 10% difference. The unique mechanical characterization method used is generalizable to diverse load conditions and will be used to match load impedance to muscle tissue impedance for a wide variety of applications.

  8. Composite structures for the enhancement of nonlinear optical materials.

    Science.gov (United States)

    Neeves, A E; Birnboim, M H

    1988-12-01

    Calculations of the nonlinear optical behavior are developed for model composites consisting of nanospheres with a metallic core and a nonlinear shell suspended in a nonlinear medium. The concept for the enhancement of optical phase conjugation from all these nonlinear regions is that the optical field can be concentrated both inside and in the neighborhood of the metallic core, aided by surface-mediated plasmon resonance. Calculations for gold cores and aluminum cores indicate that phase-conjugate reflectivity enhancements of 10(8) may be possible.

  9. Characterizaticr of Solid State Laser and Nonlinear Optical Materials.

    Science.gov (United States)

    1995-02-02

    materials useful in the different methods for obtaining frequency agility: narrow line emitters with multiple lasing channels and nonlinear optical materials . In...codoped with two or more rare earth ions were studied and computers models developed to explain their spectral dynamics. The nonlinear optical materials investigated

  10. A Photonic Basis for Deriving Nonlinear Optical Response

    Science.gov (United States)

    Andrews, David L.; Bradshaw, David S.

    2009-01-01

    Nonlinear optics is generally first presented as an extension of conventional optics. Typically the subject is introduced with reference to a classical oscillatory electric polarization, accommodating correction terms that become significant at high intensities. The material parameters that quantify the extent of the nonlinear response are cast as…

  11. Nonlinear refractive index of optical crystals

    Science.gov (United States)

    Adair, Robert; Chase, L. L.; Payne, Stephen A.

    1989-02-01

    The nonlinear refractive indices (n2) of a large number of optical crystals have been measured at a wavelength near one micrometer with use of nearly degenerate three-wave mixing. The measurements are compared with the predictions of an empirical formula derived by Boling, Glass, and Owyoung. This formula, which relates n2 to the linear refractive index and its dispersion, is shown to be accurate to within about 30% for materials with nonlinear indices ranging over 3 orders of magnitude. Measurements for a number of binary oxide and fluoride crystals have been analyzed under the assumption that the hyperpolarizability of the anion is much larger than that of the cation. It is found that the hyperpolarizability of oxygen varies by a factor of 10, and that of fluorine varies by a factor of 7, depending on the size of the coordinating cation. This behavior is similar to that of the linear polarizability, although the hyperpolarizability is much more sensitive than the linear polarizability to the identity of the cation. The measured halide ion hyperpolarizabilities for several alkali-halide crystals are in reasonable agreement with recent self-consistent calculations. A semiempirical model was proposed by Wilson and Curtis to account for the dependence of the linear anionic polarizability on the radius of the cation. This model also accounts quite well for the variation of the hyperpolarizability of both fluorine and oxygen, except for cation partners that have filled or unfilled d-electron shells. The nonlinear indices of a number of complex oxides (i.e., those with more than one cation) have been calculated from the partial hyperpolarizabilities deduced from the data for the binary oxides. The calculated and measured values of n2 agree to within an average error of 13%.

  12. High nonlinear optical anisotropy of urea nanofibers

    Science.gov (United States)

    Isakov, D.; de Matos Gomes, E.; Belsley, M.; Almeida, B.; Martins, A.; Neves, N.; Reis, R.

    2010-07-01

    Nanofibers consisting of the optically nonlinear organic molecule urea embedded in both poly(ethylene oxide) (PEO) and poly(vinyl alcohol) (PVA) polymers were produced by the electrospinning technique. The second-harmonic generation produced by aligned fiber mats of these materials displays a strong dependence on the polarization of the incident light. In PVA-urea nanofibers the effectiveness in generating of the second-harmonic light is as high as that of a pure urea powder with an average grain size of 110 μm. The results suggest that single crystalline urea nanofibers were achieved with a long-range crystalline order extending into the range of 2-4 μm with PVA as the host polymer.

  13. Visualization of the 3-D topography of the optic nerve head through a passive stereo vision model

    Science.gov (United States)

    Ramirez, Juan M.; Mitra, Sunanda; Morales, Jose

    1999-01-01

    This paper describes a system for surface recovery and visualization of the 3D topography of the optic nerve head, as support of early diagnosis and follow up to glaucoma. In stereo vision, depth information is obtained from triangulation of corresponding points in a pair of stereo images. In this paper, the use of the cepstrum transformation as a disparity measurement technique between corresponding windows of different block sizes is described. This measurement process is embedded within a coarse-to-fine depth-from-stereo algorithm, providing an initial range map with the depth information encoded as gray levels. These sparse depth data are processed through a cubic B-spline interpolation technique in order to obtain a smoother representation. This methodology is being especially refined to be used with medical images for clinical evaluation of some eye diseases such as open angle glaucoma, and is currently under testing for clinical evaluation and analysis of reproducibility and accuracy.

  14. In-situ biofouling assessment in spacer filled channels using optical coherence tomography (OCT): 3D biofilm thickness mapping

    KAUST Repository

    Fortunato, Luca

    2017-01-13

    Membrane systems for water purification can be seriously hampered by biofouling. The use of optical coherence tomography (OCT) to investigate biofilms in membrane systems has recently increased due to the ability to do the characterization in-situ and non-destructively The OCT biofilm thickness map is presented for the first time as a tool to assess biofilm spatial distribution on a surface. The map allows the visualization and evaluation of the biofilm formation and growth in membrane filtration systems through the use of a false color scale. The biofilm development was monitored with OCT to evaluate the suitability of the proposed approach. A 3D time series analysis of biofilm development in a spacer filled channel representative of a spiral-wound membrane element was performed. The biofilm thickness map enables the time-resolved and spatial-resolved evaluation and visualization of the biofilm deposition pattern in-situ non-destructively.

  15. 3D optical see-through head-mounted display based augmented reality system and its application

    Science.gov (United States)

    Zhang, Zhenliang; Weng, Dongdong; Liu, Yue; Xiang, Li

    2015-07-01

    The combination of health and entertainment becomes possible due to the development of wearable augmented reality equipment and corresponding application software. In this paper, we implemented a fast calibration extended from SPAAM for an optical see-through head-mounted display (OSTHMD) which was made in our lab. During the calibration, the tracking and recognition techniques upon natural targets were used, and the spatial corresponding points had been set in dispersed and well-distributed positions. We evaluated the precision of this calibration, in which the view angle ranged from 0 degree to 70 degrees. Relying on the results above, we calculated the position of human eyes relative to the world coordinate system and rendered 3D objects in real time with arbitrary complexity on OSTHMD, which accurately matched the real world. Finally, we gave the degree of satisfaction about our device in the combination of entertainment and prevention of cervical vertebra diseases through user feedbacks.

  16. Simulation of 3D parachute fluid-structure interaction based on nonlinear finite element method and preconditioning finite volume method

    Institute of Scientific and Technical Information of China (English)

    Fan Yuxin; Xia Jian

    2014-01-01

    A fluid–structure interaction method combining a nonlinear finite element algorithm with a preconditioning finite volume method is proposed in this paper to simulate parachute tran-sient dynamics. This method uses a three-dimensional membrane–cable fabric model to represent a parachute system at a highly folded configuration. The large shape change during parachute infla-tion is computed by the nonlinear Newton–Raphson iteration and the linear system equation is solved by the generalized minimal residual (GMRES) method. A membrane wrinkling algorithm is also utilized to evaluate the special uniaxial tension state of membrane elements on the parachute canopy. In order to avoid large time expenses during structural nonlinear iteration, the implicit Hil-ber–Hughes–Taylor (HHT) time integration method is employed. For the fluid dynamic simula-tions, the Roe and HLLC (Harten–Lax–van Leer contact) scheme has been modified and extended to compute flow problems at all speeds. The lower–upper symmetric Gauss–Seidel (LU-SGS) approximate factorization is applied to accelerate the numerical convergence speed. Finally, the test model of a highly folded C-9 parachute is simulated at a prescribed speed and the results show similar characteristics compared with experimental results and previous literature.

  17. Simulation of 3D parachute fluid–structure interaction based on nonlinear finite element method and preconditioning finite volume method

    Directory of Open Access Journals (Sweden)

    Fan Yuxin

    2014-12-01

    Full Text Available A fluid–structure interaction method combining a nonlinear finite element algorithm with a preconditioning finite volume method is proposed in this paper to simulate parachute transient dynamics. This method uses a three-dimensional membrane–cable fabric model to represent a parachute system at a highly folded configuration. The large shape change during parachute inflation is computed by the nonlinear Newton–Raphson iteration and the linear system equation is solved by the generalized minimal residual (GMRES method. A membrane wrinkling algorithm is also utilized to evaluate the special uniaxial tension state of membrane elements on the parachute canopy. In order to avoid large time expenses during structural nonlinear iteration, the implicit Hilber–Hughes–Taylor (HHT time integration method is employed. For the fluid dynamic simulations, the Roe and HLLC (Harten–Lax–van Leer contact scheme has been modified and extended to compute flow problems at all speeds. The lower–upper symmetric Gauss–Seidel (LU-SGS approximate factorization is applied to accelerate the numerical convergence speed. Finally, the test model of a highly folded C-9 parachute is simulated at a prescribed speed and the results show similar characteristics compared with experimental results and previous literature.

  18. Optical bistability in a nonlinear-shell-coated metallic nanoparticle

    Science.gov (United States)

    Chen, Hongli; Zhang, Youming; Zhang, Baile; Gao, Lei

    2016-01-01

    We provide a self-consistent mean field approximation in the framework of Mie scattering theory to study the optical bistability of a metallic nanoparticle coated with a nonlinear shell. We demonstrate that the nanoparticle coated with a weakly nonlinear shell exhibits optical bistability in a broad range of incident optical intensity. This optical bistability critically relies on the geometry of the shell-coated nanoparticle, especially the fractional volume of the metallic core. The incident wavelength can also affect the optical bistability. Through an optimization-like process, we find a design with broader bistable region and lower threshold field by adjusting the size of the nonlinear shell, the fractional volume of the metallic core, and the incident wavelength. These results may find potential applications in optical bistable devices such as all-optical switches, optical transistors and optical memories. PMID:26907967

  19. Retinal nerve fiber layer thickness of middle aged or elderly people measured by 3D optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Li Li

    2015-11-01

    Full Text Available AIM: To build the reference values of normal eye retinal nerve fiber layer(RNFLthickness on middle aged people between 40~69 years old, and infer the baseline data for early diagnosis of glaucoma. METHODS:A total of 180 eyes from 90 healthy subjects(age ranged from 40~69 years oldwere recruited for this study. Topcon 3D optical coherence tomography(OCT-2000(Ver 8.0was used to measure RNFL thickness. Each subject was performed circular scans around the optic nerve with a circle size of 3.4mm. Clock-hour, quadrant and total average RNFL thicknesses were recorded. The data was analyzed with SPSS statistical. The relationship between age, gender and laterality was analyzed, and the reference value for normal eye RNFL thickness parameters was obtained, RESULTS:Normal RNFL thickness distribution was bimodal curve type in 40~69 year-old middle aged or elderly people. RNFL thickness was decreased for temporal quadrant, followed by nasal, superior, inferior. RNFL thickness at 10 o'clock, 5 o'clock, 6 o'clock, superior got thinner with age prolong. Except 10 o'clock(PP>0.05. The RNFL thickness at 11 o'clock was associated with different gender. the RNFL thickness at 11 o'clock, 12 o'clock, 1 o'clock, 4 o'clock, superior, nasal was associated with different eyes, the differences was statistically significant between different eyes(PCONCLUSION: Topcon 3D OCT-2000 is effectively used to measure the RNFL thickness of 40~69 years people and provide diagnostic basis for early diagnosis of glaucoma.

  20. Laser And Nonlinear Optical Materials For Laser Remote Sensing

    Science.gov (United States)

    Barnes, Norman P.

    2005-01-01

    NASA remote sensing missions involving laser systems and their economic impact are outlined. Potential remote sensing missions include: green house gasses, tropospheric winds, ozone, water vapor, and ice cap thickness. Systems to perform these measurements use lanthanide series lasers and nonlinear devices including second harmonic generators and parametric oscillators. Demands these missions place on the laser and nonlinear optical materials are discussed from a materials point of view. Methods of designing new laser and nonlinear optical materials to meet these demands are presented.

  1. Design, synthesis and characterization of novel nonlinear optical chromophores for electro-optical applications

    Science.gov (United States)

    Liu, Feng

    This dissertation involves the design, synthesis and characterization of second order nonlinear optical chromophores for electro-optic applications. The design concept, that poling efficiency and macroscopic nonlinearities can be improved by modifying a chromophore's shape, has been explored. Chapter 1 gives an introduction into theoretical background of nonlinear optics and electro-optic phenomenon in organic molecules and poled polymers. Chapter 2 involves the design and synthesis of GLD-2 and GLD-3 chromophores, both with bulky substituents on the ring-fused bridge. The optical studies and HRS measurement show that the two alkyl groups on the bridge blueshift the lambdamax in chloroform by 20 nm and decrease the beta values. DSC and TGA thermal analysis show Td of GLD-2 and GLD-3 over 240°C. The maximum achievable r33 of GLD-2/PMMA is 61 pm/V, compared to the 92.4 pm/V of GLD-1/PMMA. But GLD-2/APC shows r33 of 45.2pm/V, higher than GLD-1/APC due to the improved compatibility with APC. The optical loss of 13 wt% GLD-2/PMMA at 1.55mum is 1.4 dB compared to the 2.3 dB of 17 wt% GLD-1/PMMA. Optical loss studies prove that adding two bulky substituents on bridge help attenuate electrostatic interactions. GLD-3 show deteriorated solubility in common used organic solvents, probably due to the combination of two TBDMS and two lengthy alkyl groups. Chapter 3 presents synthesis of thiophene-based chromophores with variously positioned TBDMS groups. The optical studies of these chromophores show one TBDMSO substitution on the thiophene bridge yields little influence on the lambda max in chloroform. FTCDS chromophore with two TBDMS groups, one on donor and one on thiophene bridge, shows to be the best structure with regards the thermal stability and achievable maximum EO coefficient value, 65.9 pm/V, at only 24 wt% loading density at 1.3 mum. Chapter 4 deals with three novel bridges for NLO chromophores. Synthetic methodologies of the diketone precursor of rigidified

  2. Bidirectional all-optical switches based on highly nonlinear optical fibers

    Science.gov (United States)

    Liu, Wenjun; Yang, Chunyu; Liu, Mengli; Yu, Weitian; Zhang, Yujia; Lei, Ming; Wei, Zhiyi

    2017-05-01

    All-optical switches have become one of the research focuses of nonlinear optics due to their fast switching speed. They have been applied in such fields as ultrafast optics, all-optical communication and all-optical networks. In this paper, based on symbolic computation, bidirectional all-optical switches are presented using analytic two-soliton solutions. Various types of soliton interactions are analyzed through choosing the different parameters of high-order dispersion and nonlinearity. Results indicate that bidirectional all-optical switches can be effectively achieved using highly nonlinear optical fibers.

  3. Modeling seismic wave propagation and amplification in 1D/2D/3D linear and nonlinear unbounded media

    CERN Document Server

    Semblat, Jean-François

    2011-01-01

    To analyze seismic wave propagation in geological structures, it is possible to consider various numerical approaches: the finite difference method, the spectral element method, the boundary element method, the finite element method, the finite volume method, etc. All these methods have various advantages and drawbacks. The amplification of seismic waves in surface soil layers is mainly due to the velocity contrast between these layers and, possibly, to topographic effects around crests and hills. The influence of the geometry of alluvial basins on the amplification process is also know to be large. Nevertheless, strong heterogeneities and complex geometries are not easy to take into account with all numerical methods. 2D/3D models are needed in many situations and the efficiency/accuracy of the numerical methods in such cases is in question. Furthermore, the radiation conditions at infinity are not easy to handle with finite differences or finite/spectral elements whereas it is explicitely accounted in the B...

  4. Optical limiter based on two-dimensional nonlinear photonic crystals

    Science.gov (United States)

    Belabbas, Amirouche; Lazoul, Mohamed

    2016-04-01

    The aim behind this work is to investigate the capabilities of nonlinear photonic crystals to achieve ultra-fast optical limiters based on third order nonlinear effects. The purpose is to combine the actions of nonlinear effects with the properties of photonic crystals in order to activate the photonic band according to the magnitude of the nonlinear effects, themselves a function of incident laser power. We are interested in designing an optical limiter based nonlinear photonic crystal operating around 1064 nm and its second harmonic at 532 nm. Indeed, a very powerful solid-state laser that can blind or destroy optical sensors and is widely available and easy to handle. In this work, we perform design and optimization by numerical simulations to determine the better structure for the nonlinear photonic crystal to achieve compact and efficient integrated optical limiter. The approach consists to analyze the band structures in Kerr-nonlinear two-dimensional photonic crystals as a function of the optical intensity. We confirm that these bands are dynamically red-shifted with regard to the bands observed in linear photonic crystals or in the case of weak nonlinear effects. The implemented approach will help to understand such phenomena as intensitydriven optical limiting with Kerr-nonlinear photonic crystals.

  5. 3D Forest structure analysis from optical and LIDAR data / Análise 3D da estrutura da floresta com dados ópticos e da LIDAR

    Directory of Open Access Journals (Sweden)

    Stefan Lang

    2006-10-01

    Full Text Available In Austria about half of the entire area (46 % is covered by forests. The majority of these forests are highly managed and controlled in growth. Besides timber production, forest ecosystems play a multifunctional role including climate control, habitat provision and, especially in Austria, protection of settlements. The interrelationships among climatic, ecological, social and economic dimensions of forests require technologies for monitoring both the state and the development of forests. This comprises forest structure, species and age composition and, forest integrity in general. Assessing forest structure for example enables forest managers and natural risk engineers to evaluate whether a forest can fulfill its protective function or not. Traditional methods for assessing forest structure like field inventories and aerial photo interpretation are intrinsically limited in providing spatially continuous information over a large area. The Centre for Geoinformatics (Z_GIS in collaboration with the National Park Bayerischer Wald, Germany and the Stand Montafon, Austria, has tested and applied advanced approaches of integrating multispectral optical data and airborne laser scanning (ALS data for (1 forest stand delineation, (2 single tree detection and (3 forest structure analysis. As optical data we used RGBI line scanner data and CIR air-photos. ALS data were raw point data (10 pulses per sqm and normalized crown models (nCM at 0.5 m and 1 m resolution. (1 Automated stand delineation was done by (a translating a key for manual mapping of forest development phases into a rule-based system via object-relationship modeling (ORM; and (b by performing multi-resolution segmentation and GIS analysis. (2 Strategies for single tree detection using raw ALS data included (a GIS modelling based on a region-growth local maxima algorithm and (b object-based image analysis using super class information class-specific rule sets. (3 Vertical forest structure has

  6. Nonlinear super-resolution nano-optics and applications

    CERN Document Server

    Wei, Jingsong

    2015-01-01

    This book covers many advances in the subjects of nano-optics and nano photonics. The author describes the principle and technical schematics of common methods for breaking through the optical diffraction limit and focuses on realizing optical super-resolution with nonlinear effects of thin film materials. The applications of nonlinear optical super-resolution effects in nano-data storage, nanolithography, and nano-imaging are also presented. This book is useful to graduate students majoring in optics and nano science and also serves as a reference book for academic researchers, engineers, technical professionals in the fields of super-resolution optics and laser techniques, nano-optics and nano photonics, nano-data storage, nano imaging, micro/nanofabrication and nanolithography and nonlinear optics.

  7. NIKE3D a nonlinear, implicit, three-dimensional finite element code for solid and structural mechanics user's manual update summary

    Energy Technology Data Exchange (ETDEWEB)

    Puso, M; Maker, B N; Ferencz, R M; Hallquist, J O

    2000-03-24

    This report provides the NIKE3D user's manual update summary for changes made from version 3.0.0 April 24, 1995 to version 3.3.6 March 24,2000. The updates are excerpted directly from the code printed output file (hence the Courier font and formatting), are presented in chronological order and delineated by NIKE3D version number. NIKE3D is a fully implicit three-dimensional finite element code for analyzing the finite strain static and dynamic response of inelastic solids, shells, and beams. Spatial discretization is achieved by the use of 8-node solid elements, 2-node truss and beam elements, and 4-node membrane and shell elements. Thirty constitutive models are available for representing a wide range of elastic, plastic, viscous, and thermally dependent material behavior. Contact-impact algorithms permit gaps, frictional sliding, and mesh discontinuities along material interfaces. Several nonlinear solution strategies are available, including Full-, Modified-, and Quasi-Newton methods. The resulting system of simultaneous linear equations is either solved iteratively by an element-by-element method, or directly by a direct factorization method.

  8. Improved fiber nonlinearity mitigation in dispersion managed optical OFDM links

    Science.gov (United States)

    Tamilarasan, Ilavarasan; Saminathan, Brindha; Murugappan, Meenakshi

    2017-02-01

    Fiber nonlinearity is seen as a capacity limiting factor in OFDM based dispersion managed links since the Four Wave Mixing effects become enhanced due to the high PAPR. In this paper, the authors have compared the linear and nonlinear PAPR reduction techniques for fiber nonlinearity mitigation in OFDM based dispersion managed links. In the existing optical systems, linear transform techniques such as SLM and PTS have been implemented to reduce nonlinear effects. In the proposed study, superior performance of the L2-by-3 nonlinear transform technique is demonstrated for PAPR reduction to mitigate fiber nonlinearities. The performance evaluation is carried out by interfacing multiple simulators. The results of both linear and nonlinear transform techniques have been compared and the results show that nonlinear transform technique outperforms the linear transform in terms of nonlinearity mitigation and improved BER performance.

  9. Application of the Minkowski functionals in 3D to high-resolution MR images of trabecular bone: prediction of the biomechanical strength by nonlinear topological measures

    Science.gov (United States)

    Boehm, Holger F.; Link, Thomas M.; Monetti, Roberto A.; Mueller, Dirk; Rummeny, Ernst J.; Newitt, David; Majumdar, Sharmila; Raeth, Christoph W.

    2004-05-01

    Multi-dimensional convex objects can be characterized with respect to shape, structure, and the connectivity of their components using a set of morphological descriptors known as the Minkowski functionals. In a 3D Euclidian space, these correspond to volume, surface area, mean integral curvature, and the Euler-Poincaré characteristic. We introduce the Minkowski functionals to medical image processing for the morphological analysis of trabecular bone tissue. In the context of osteoporosis-a metabolic disorder leading to a weakening of bone due to deterioration of micro-architecture-the structure of bone increasingly gains attention in the quantification of bone quality. The trabecular architecture of healthy cancellous bone consists of a complex 3D system of inter-connected mineralised elements whereas in osteoporosis the micro-structure is dominated by gaps and disconnections. At present, the standard parameter for diagnosis and assessment of fracture risk in osteoporosis is the bone mineral density (BMD) - a bulk measure of mineralisation irrespective of structural texture characteristics. With the development of modern imaging modalities (high resolution MRI, micro-CT) with spatial resolutions allowing to depict individual trabeculae bone micro-architecture has successfully been analysed using linear, 2- dimensional structural measures adopted from standard histo-morphometry. The preliminary results of our study demonstrate that due to the complex - i.e. the non-linear - network of trabecular bone structures non-linear measures in 3D are superior to linear ones in predicting mechanical properties of trabecular bone from structural information extracted from high resolution MR image data.

  10. Nonlinear optical properties of Au/PVP composite thin films

    Institute of Scientific and Technical Information of China (English)

    Shen Hong; Cheng Bo-Lin; Lu Guo-Wei; Wang Wei-Tian; Guan Dong-Yi; Chen Zheng-Hao; Yang Guo-Zhen

    2005-01-01

    Colloidal Au and poly(vinylpyrrolidone) (PVP) composite thin films are fabricated by spin-coating method. Linear optical absorption measurements of the Au/PVP composite films indicate an absorption peak around 530 nm due to the surface plasmon resonance of gold nanoparticles. Nonlinear optical properties are studied using standard Z-scan technique, and experimental results show large optical nonlinearities of the Au/PVP composite films. A large value of films.

  11. Comparison of 3D double inversion recovery and 2D STIR FLAIR MR sequences for the imaging of optic neuritis: pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Hodel, Jerome; Bocher, Anne-Laure; Pruvo, Jean-Pierre; Leclerc, Xavier [Hopital Roger Salengro, Department of Neuroradiology, Lille (France); Outteryck, Olivier; Zephir, Helene; Vermersch, Patrick [Hopital Roger Salengro, Department of Neurology, Lille (France); Lambert, Oriane [Fondation Ophtalmologique Rothschild, Department of Neuroradiology, Paris (France); Benadjaoud, Mohamed Amine [Radiation Epidemiology Team, Inserm, CESP Centre for Research in Epidemiology and Population Health, U1018, Villejuif (France); Chechin, David [Philips Medical Systems, Suresnes (France)

    2014-12-15

    We compared the three-dimensional (3D) double inversion recovery (DIR) magnetic resonance imaging (MRI) sequence with the coronal two-dimensional (2D) short tau inversion recovery (STIR) fluid-attenuated inversion recovery (FLAIR) for the detection of optic nerve signal abnormality in patients with optic neuritis (ON). The study group consisted of 31 patients with ON (44 pathological nerves) confirmed by visual-evoked potentials used as the reference. MRI examinations included 2D coronal STIR FLAIR and 3D DIR with 3-mm coronal reformats to match with STIR FLAIR. Image artefacts were graded for each portion of the optic nerves. Each set of MR images (2D STIR FLAIR, DIR reformats and multiplanar 3D DIR) was examined independently and separately for the detection of signal abnormality. Cisternal portion of optic nerves was better delineated with DIR (p < 0.001), while artefacts impaired analysis in four patients with STIR FLAIR. Inter-observer agreement was significantly improved (p < 0.001) on 3D DIR (κ = 0.96) compared with STIR FLAIR images (κ = 0.60). Multiplanar DIR images reached the best performance for the diagnosis of ON (95 % sensitive and 94 % specific). Our study showed a high sensitivity and specificity of 3D DIR compared with STIR FLAIR for the detection of ON. These findings suggest that the 3D DIR sequence may be more useful in patients suspected of ON. (orig.)

  12. 3D nondestructive testing system with an affordable multiple reference optical-delay-based optical coherence tomography.

    Science.gov (United States)

    Dsouza, Roshan; Subhash, Hrebesh M; Neuhaus, Kai; Hogan, Josh; Wilson, Carol; Leahy, Martin

    2015-06-20

    Optical coherence tomography (OCT) is emerging as a powerful noncontact imaging technique, allowing high-quality cross-sectional imaging of scattering specimens nondestructively. However, the complexity and cost of current embodiments of an OCT system limit its use in various nondestructive testing (NDT) applications at resource-limited settings. In this paper, we demonstrate the feasibility of a novel low-cost OCT system for a range of nondestructive testing (NDT) applications. The proposed imaging system is based on an enhanced time-domain OCT system with a low cost and small form factor reference arm optical delay, called multiple reference OCT (MR-OCT), which uses a miniature voice coil actuator and a partial mirror for extending the axial scan range. The proposed approach is potentially a low-cost, compact, and unique optical imaging modality for a range of NDT applications in a low-resource setting. Using this method, we demonstrated the capability of MR-OCT to perform cross-sectional and volumetric imaging at 1200 A-scans per second.

  13. Nonlinear automatic landing control of unmanned aerial vehicles on moving platforms via a 3D laser radar

    Science.gov (United States)

    Hervas, Jaime Rubio; Reyhanoglu, Mahmut; Tang, Hui

    2014-12-01

    This paper presents a motion tracking and control system for automatically landing Unmanned Aerial Vehicles (UAVs) on an oscillating platform using Laser Radar (LADAR) observations. The system itself is assumed to be mounted on a ship deck. A full nonlinear mathematical model is first introduced for the UAV. The ship motion is characterized by a Fourier transform based method which includes a realistic characterization of the sea waves. LADAR observation models are introduced and an algorithm to process those observations for yielding the relative state between the vessel and the UAV is presented, from which the UAV's state relative to an inertial frame can be obtained and used for feedback purposes. A sliding mode control algorithm is derived for tracking a landing trajectory defined by a set of desired waypoints. An extended Kalman filter (EKF) is proposed to account for process and observation noises in the design of a state estimator. The effectiveness of the control algorithm is illustrated through a simulation example.

  14. 3D Cloud Tomography, Followed by Mean Optical and Microphysical Properties, with Multi-Angle/Multi-Pixel Data

    Science.gov (United States)

    Davis, A. B.; von Allmen, P. A.; Marshak, A.; Bal, G.

    2010-12-01

    -type model is used where the cloud surface "emits" either reflected (sunny-side) or transmitted (shady-side) light at different levels. As it turns out, the reflected/transmitted light ratio yields an approximate cloud optical thickness. Another approach is to invoke tomography techniques to define the volume occupied by the cloud using, as it were, cloud masks for each direction of observation. In the shape and opacity refinement phase, initial guesses along with solar and viewing geometry information are used to predict radiance in each pixel using a fast diffusion model for the 3D RT in MISR's non-absorbing red channel (275 m resolution). Refinement is constrained and stopped when optimal resolution is reached. Finally, multi-pixel/mono-angle MODIS data for the same cloud (at comparable 250 m resolution) reveals the desired droplet size information, hence the volume-averaged LWC. This is an ambitious remote sensing science project drawing on cross-disciplinary expertise gained in medical imaging using both X-ray and near-IR sources and detectors. It is high risk but with potentially high returns not only for the cloud modeling community but also aerosol and surface characterization in the presence of broken 3D clouds.

  15. Nonlinear Optical Materials for the Smart Filtering of Optical Radiation.

    Science.gov (United States)

    Dini, Danilo; Calvete, Mário J F; Hanack, Michael

    2016-11-23

    The control of luminous radiation has extremely important implications for modern and future technologies as well as in medicine. In this Review, we detail chemical structures and their relevant photophysical features for various groups of materials, including organic dyes such as metalloporphyrins and metallophthalocyanines (and derivatives), other common organic materials, mixed metal complexes and clusters, fullerenes, dendrimeric nanocomposites, polymeric materials (organic and/or inorganic), inorganic semiconductors, and other nanoscopic materials, utilized or potentially useful for the realization of devices able to filter in a smart way an external radiation. The concept of smart is referred to the characteristic of those materials that are capable to filter the radiation in a dynamic way without the need of an ancillary system for the activation of the required transmission change. In particular, this Review gives emphasis to the nonlinear optical properties of photoactive materials for the function of optical power limiting. All known mechanisms of optical limiting have been analyzed and discussed for the different types of materials.

  16. Optical and Nonlinear Optical Response of Light Sensor Thin Films

    Directory of Open Access Journals (Sweden)

    S. Z. Weisz

    2005-04-01

    Full Text Available For potential ultrafast optical sensor application, both VO2 thin films andnanocomposite crystal-Si enriched SiO2 thin films grown on fused quartz substrates weresuccessfully prepared using pulsed laser deposition (PLD and RF co-sputteringtechniques. In photoluminescence (PL measurement c-Si/SiO2 film containsnanoparticles of crystal Si exhibits strong red emission with the band maximum rangingfrom 580 to 750 nm. With ultrashort pulsed laser excitation all films show extremelyintense and ultrafast nonlinear optical (NLO response. The recorded holography fromall these thin films in a degenerate-four-wave-mixing configuration shows extremelylarge third-order response. For VO2 thin films, an optically induced semiconductor-tometalphase transition (PT immediately occurred upon laser excitation. it accompanied.It turns out that the fast excited state dynamics was responsible to the induced PT. For c-Si/SiO2 film, its NLO response comes from the contribution of charge carriers created bylaser excitation in conduction band of the c-Si nanoparticles. It was verified byintroducing Eu3+ which is often used as a probe sensing the environment variations. Itturns out that the entire excited state dynamical process associated with the creation,movement and trapping of the charge carriers has a characteristic 500 ps duration.

  17. Short term reproducibility of a high contrast 3-D isotropic optic nerve imaging sequence in healthy controls

    Science.gov (United States)

    Harrigan, Robert L.; Smith, Alex K.; Mawn, Louise A.; Smith, Seth A.; Landman, Bennett A.

    2016-03-01

    The optic nerve (ON) plays a crucial role in human vision transporting all visual information from the retina to the brain for higher order processing. There are many diseases that affect the ON structure such as optic neuritis, anterior ischemic optic neuropathy and multiple sclerosis. Because the ON is the sole pathway for visual information from the retina to areas of higher level processing, measures of ON damage have been shown to correlate well with visual deficits. Increased intracranial pressure has been shown to correlate with the size of the cerebrospinal fluid (CSF) surrounding the ON. These measures are generally taken at an arbitrary point along the nerve and do not account for changes along the length of the ON. We propose a high contrast and high-resolution 3-D acquired isotropic imaging sequence optimized for ON imaging. We have acquired scan-rescan data using the optimized sequence and a current standard of care protocol for 10 subjects. We show that this sequence has superior contrast-to-noise ratio to the current standard of care while achieving a factor of 11 higher resolution. We apply a previously published automatic pipeline to segment the ON and CSF sheath and measure the size of each individually. We show that these measures of ON size have lower short- term reproducibility than the population variance and the variability along the length of the nerve. We find that the proposed imaging protocol is (1) useful in detecting population differences and local changes and (2) a promising tool for investigating biomarkers related to structural changes of the ON.

  18. Topology optimization of nonlinear optical devices

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard

    2011-01-01

    This paper considers the design of nonlinear photonic devices. The nonlinearity stems from a nonlinear material model with a permittivity that depends on the local time-averaged intensity of the electric field. A finite element model is developed for time-harmonic wave propagation and an incremen......This paper considers the design of nonlinear photonic devices. The nonlinearity stems from a nonlinear material model with a permittivity that depends on the local time-averaged intensity of the electric field. A finite element model is developed for time-harmonic wave propagation...

  19. Nonlinear Optical Response of Conjugated Polymer to Electric Field

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yu-fang; ZHUANG De-xin; CUI Bin

    2005-01-01

    The organic π-conjugated polymers are of major interest materials for the use in electro-optical and nonlinear optical devices. In this work, for a selected polyacetylene chain, the optical absorption spectra in UV/Vis regime as well as the linear polarizabilitiy and nonlinear hyperpolarizability are calculated by using quantum chemical ab initio and semiempirical methods. The relationship of its optical property to electric field is obtained. Some physical mechanism of electric field effect on molecular optical property is discussed by means of electron distribution and intramolecular charge transfer.

  20. Proceedings of the Workshop on 3-D Optical Memories (1st) Held in Snowbird, Utah on 12-13 March 1990.

    Science.gov (United States)

    1990-03-01

    issues addressed the possible utilizations of 3-D memories. It was suggested that in addition to their usage as secondary storage, 3-D memories could...SLMs operating at their thermal limit, precluding its usage for mass storage. On the other hand, the three dimensional magnetic bubble storage and...progress in solving these problems and have successfully stored and retreived 2-D data from optical disks Ŗ 5s 26. The availabilty of this technology

  1. A 3-D Time-Domain Coupled Model for Nonlinear Waves Acting on A Box-Shaped Ship Fixed in A Harbor

    Institute of Scientific and Technical Information of China (English)

    WANG Da-guo; ZOU Zhi-li; THAM Leslie George

    2011-01-01

    A 3-D time-domain numerical coupled model is developed to obtain an efficient method for nonlinear waves acting on a box-shaped ship fixed in a harbor.The domain is divided into the inner domain and the outer domain.The inner domain is the area beneath the ship and the flow is described by the simplified Euler equations.The remaining area is the outer domain and the flow is defined by the higher-order Boussinesq equations in order to consider the nonlinearity of the wave motions.Along the interface boundaries between the inner domain and the outer domain,the volume flux is assumed to be continuous and the wave pressures are equal.Relevant physical experiment is conducted to validate the present model and it is shown that the numerical results agree with the experimental data.Compared the coupled model with the flow in the inner domain governed by the Laplace equation,the present coupled model is more efficient and its solution procedure is simpler,which is particularly useful for the study on the effect of the nonlinear waves acting on a fixed box-shaped ship in a large harbor.

  2. Non-linear optical microscopy sheds light on cardiovascular disease.

    Directory of Open Access Journals (Sweden)

    Valentina Caorsi

    Full Text Available Many cardiac diseases have been associated with increased fibrosis and changes in the organization of fibrillar collagen. The degree of fibrosis is routinely analyzed with invasive histological and immunohistochemical methods, giving a limited and qualitative understanding of the tissue's morphological adaptation to disease. Our aim is to quantitatively evaluate the increase in fibrosis by three-dimensional imaging of the collagen network in the myocardium using the non-linear optical microscopy techniques Two-Photon Excitation microscopy (TPE and Second Harmonic signal Generation (SHG. No sample staining is needed because numerous endogenous fluorophores are excited by a two-photon mechanism and highly non-centrosymmetric structures such as collagen generate strong second harmonic signals. We propose for the first time a 3D quantitative analysis to carefully evaluate the increased fibrosis in tissue from a rat model of heart failure post myocardial infarction. We show how to measure changes in fibrosis from the backward SHG (B(SHG alone, as only backward-propagating SHG is accessible for true in vivo applications. A 5-fold increase in collagen I fibrosis is detected in the remote surviving myocardium measured 20 weeks after infarction. The spatial distribution is also shown to change markedly, providing insight into the morphology of disease progression.

  3. Non-Linear Optical Microscopy Sheds Light on Cardiovascular Disease

    Science.gov (United States)

    Caorsi, Valentina; Toepfer, Christopher; Sikkel, Markus B.; Lyon, Alexander R.; MacLeod, Ken; Ferenczi, Mike A.

    2013-01-01

    Many cardiac diseases have been associated with increased fibrosis and changes in the organization of fibrillar collagen. The degree of fibrosis is routinely analyzed with invasive histological and immunohistochemical methods, giving a limited and qualitative understanding of the tissue's morphological adaptation to disease. Our aim is to quantitatively evaluate the increase in fibrosis by three-dimensional imaging of the collagen network in the myocardium using the non-linear optical microscopy techniques Two-Photon Excitation microscopy (TPE) and Second Harmonic signal Generation (SHG). No sample staining is needed because numerous endogenous fluorophores are excited by a two-photon mechanism and highly non-centrosymmetric structures such as collagen generate strong second harmonic signals. We propose for the first time a 3D quantitative analysis to carefully evaluate the increased fibrosis in tissue from a rat model of heart failure post myocardial infarction. We show how to measure changes in fibrosis from the backward SHG (BSHG) alone, as only backward-propagating SHG is accessible for true in vivo applications. A 5-fold increase in collagen I fibrosis is detected in the remote surviving myocardium measured 20 weeks after infarction. The spatial distribution is also shown to change markedly, providing insight into the morphology of disease progression. PMID:23409139

  4. Nonlinear automatic landing control of unmanned aerial vehicles on moving platforms via a 3D laser radar

    Energy Technology Data Exchange (ETDEWEB)

    Hervas, Jaime Rubio; Tang, Hui [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798 (Singapore); Reyhanoglu, Mahmut [Physical Sciences Department, Embry-Riddle Aeronautical University, Daytona Beach, FL 32114 (United States)

    2014-12-10

    This paper presents a motion tracking and control system for automatically landing Unmanned Aerial Vehicles (UAVs) on an oscillating platform using Laser Radar (LADAR) observations. The system itself is assumed to be mounted on a ship deck. A full nonlinear mathematical model is first introduced for the UAV. The ship motion is characterized by a Fourier transform based method which includes a realistic characterization of the sea waves. LADAR observation models are introduced and an algorithm to process those observations for yielding the relative state between the vessel and the UAV is presented, from which the UAV's state relative to an inertial frame can be obtained and used for feedback purposes. A sliding mode control algorithm is derived for tracking a landing trajectory defined by a set of desired waypoints. An extended Kalman filter (EKF) is proposed to account for process and observation noises in the design of a state estimator. The effectiveness of the control algorithm is illustrated through a simulation example.

  5. Nonlinear fiber applications for ultrafast all-optical signal processing

    Science.gov (United States)

    Kravtsov, Konstantin

    In the present dissertation different aspects of all-optical signal processing, enabled by the use of nonlinear fibers, are studied. In particular, we focus on applications of a novel heavily GeO2-doped (HD) nonlinear fiber, that appears to be superior to many other types of nonlinear fibers because of its high nonlinearity and suitability for the use in nonlinear optical loop mirrors (NOLMs). Different functions, such as all-optical switching, thresholding, and wavelength conversion, are demonstrated with the HD fibers in the NOLM configuration. These basic functions are later used for realization of ultrafast time-domain demultiplexers, clock recovery, detectors of short pulses in stealth communications, and primitive elements for analog computations. Another important technology that benefits from the use of nonlinear fiber-based signal processing is optical code-division multiple access (CDMA). It is shown in both theory and experiment that all-optical thresholding is a unique way of improving existing detection methods for optical CDMA. Also, it is the way of implementation of true asynchronous optical spread-spectrum networks, which allows full realization of optical CDMA potential. Some aspects of quantum signal processing and manipulation of quantum states are also studied in this work. It is shown that propagation and collisions of Thirring solitons lead to a substantial squeezing of quantum states, which may find applications for generation of squeezed light.

  6. Nonlinear and Dispersive Optical Pulse Propagation

    Science.gov (United States)

    Dijaili, Sol Peter

    In this dissertation, there are basically four novel contributions to the field of picosecond pulse propagation and measurement. The first contribution is the temporal ABCD matrix which is an analog of the traditional ABCD ray matrices used in Gaussian beam propagation. The temporal ABCD matrix allows for the easy calculation of the effects of linear chirp or group velocity dispersion in the time domain. As with Gaussian beams in space, there also exists a complete Hermite-Gaussian basis in time whose propagation can be tracked with the temporal ABCD matrices. The second contribution is the timing synchronization between a colliding pulse mode-locked dye laser and a gain-switched Fabry-Perot type AlGaAs laser diode that has achieved less than 40 femtoseconds of relative timing jitter by using a pulsed optical phase lock loop (POPLL). The relative timing jitter was measured using the error voltage of the feedback loop. This method of measurement is accurate since the frequencies of all the timing fluctuations fall within the loop bandwidth. The novel element is a broad band optical cross-correlator that can resolve femtosecond time delay errors between two pulse trains. The third contribution is a novel dispersive technique of determining the nonlinear frequency sweep of a picosecond pulse with relatively good accuracy. All the measurements are made in the time domain and hence there is no time-bandwidth limitation to the accuracy. The fourth contribution is the first demonstration of cross -phase modulation in a semiconductor laser amplifier where a variable chirp was observed. A simple expression for the chirp imparted on a weak signal pulse by the action of a strong pump pulse is derived. A maximum frequency excursion of 16 GHz due to the cross-phase modulation was measured. A value of 5 was found for alpha _{xpm} which is a factor for characterizing the cross-phase modulation in a similar manner to the conventional linewidth enhancement factor, alpha.

  7. Linear and nonlinear optical properties of chalcogenide microstructured optical fibers

    Science.gov (United States)

    Trolès, Johann; Brilland, Laurent; Caillaud, Celine; Renversez, Gilles; Mechin, David; Adam, Jean-Luc

    2015-03-01

    Chalcogenide glasses are known for their large transparency in the mid-infrared and their high linear refractive index (>2). They present also a high non-linear coefficient (n2), 100 to 1000 times larger than for silica, depending on the composition. we have developed a casting method to prepare the microstructured chalcogenide preform. This method allows optical losses as low as 0.4 dB/m at 1.55 µm and less than 0.05 dB/m in the mid IR. Various chalcogenide MOFs operating in the IR range has been fabricated in order to associate the high non-linear properties of these glasses and the original MOF properties. For example, small core fibers have been drawn to enhance the non linearities for telecom applications such as signal regeneration and generation of supercontinuum sources. On another hand, in the 3-12 µm window, single mode fibers and exposed core fibers have been realized for Gaussian beams propagation and sensors applications respectively.

  8. Nonlinear optical properties of manganese porphyrin-incorporated PVC film

    Directory of Open Access Journals (Sweden)

    Jeong-Hyon Ha

    2010-12-01

    Full Text Available We measured thermally originated solid phase nonlinear optical properties of manganese porphyrin-incorporated PVC polymer film using CW low-power Z-scan and optical power limiting methods. The nonlinear refractive index (n2 of this porphyrin film is estimated to have a negative value of 7.2 ⅹ10-5 cm2/W at 632.8 nm and to be larger than that of ZnTPP in the Nafion film. The photodegradation effect common in the solution phase appears to be minor in this solid phase system. The large nonlinear effect is thought to limit the optical power due to the aperture effect.

  9. Nonlinear optical microscopy for imaging thin films and surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Smilowitz, L.B.; McBranch, D.W.; Robinson, J.M.

    1995-03-01

    We have used the inherent surface sensitivity of second harmonic generation to develop an instrument for nonlinear optical microscopy of surfaces and interfaces. We have demonstrated the use of several nonlinear optical responses for imaging thin films. The second harmonic response of a thin film of C{sub 60} has been used to image patterned films. Two photon absorption light induced fluorescence has been used to image patterned thin films of Rhodamine 6G. Applications of nonlinear optical microscopy include the imaging of charge injection and photoinduced charge transfer between layers in semiconductor heterojunction devices as well as across membranes in biological systems.

  10. Advances in chemical physics modern nonlinear optics, pt.1

    CERN Document Server

    Rice, Stuart A

    2009-01-01

    Partial table of contents: Hyper-Rayleigh and Hyper-Raman Rotational and Vibrational Spectroscopy (T. Bancewicz & Z. Ożgo). Polarization Properties of Hyper-Rayleigh and Hyper-Raman Scatterings (M. Kozierowski). Fast Molecular Reorientation in Liquid Crystals Probed by Nonlinear Optics (J. Lalanne, et al.). Nonlinear Propagation of Laser Light of Different Polarizations (G. Rivoire). Nonlinear Magneto-Optics of Magnetically Ordered Crystals (R. Zawodny). Dynamical Questions in Quantum Optics (A. Shumovsky). Quantum Resonance Fluorescence from Mutually Correlated Atoms (Z. Fi

  11. Modeling and compensation of transmitter nonlinearity in coherent optical OFDM.

    Science.gov (United States)

    Amiralizadeh, Siamak; Nguyen, An T; Rusch, Leslie A

    2015-10-05

    We present a comprehensive study of nonlinear distortions from an optical OFDM transmitter. Nonlinearities are introduced by the combination of effects from the digital-to-analog converter (DAC), electrical power amplifier (PA) and optical modulator in the presence of high peak-to-average power ratio (PAPR). We introduce parameters to quantify the transmitter nonlinearity. High input backoff avoids OFDM signal compression from the PA, but incurs high penalties in power efficiency. At low input backoff, common PAPR reduction techniques are not effective in suppressing the PA nonlinear distortion. A bit error distribution investigation shows a technique combining nonlinear predistortion with PAPR mitigation could achieve good power efficiency by allowing low input backoff. We use training symbols to extract the transmitter nonlinear function. We show that piecewise linear interpolation (PLI) leads to an accurate transmitter nonlinearity characterization. We derive a semi-analytical solution for bit error rate (BER) that validates the PLI approximation accurately captures transmitter nonlinearity. The inverse of the PLI estimate of the nonlinear function is used as a predistorter to suppress transmitter nonlinearity. We investigate performance of the proposed scheme by Monte Carlo simulations. Our simulations show that when DAC resolution is more than 4 bits, BER below forward error correction limit of 3.8 × 10(-3) can be achieved by using predistortion with very low input power backoff for electrical PA and optical modulator.

  12. Advances in nonlinear optical materials and devices

    Science.gov (United States)

    Byer, Robert L.

    1991-01-01

    The recent progress in the application of nonlinear techniques to extend the frequency of laser sources has come from the joint progress in laser sources and in nonlinear materials. A brief summary of the progress in diode pumped solid state lasers is followed by an overview of progress in nonlinear frequency extension by harmonic generation and parametric processes. Improved nonlinear materials including bulk crystals, quasiphasematched interactions, guided wave devices, and quantum well intersubband studies are discussed with the idea of identifying areas of future progress in nonlinear materials and devices.

  13. Development of a new laser-line and CCD based optical-CT scanner for the readout of 3D radiation dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Papadakis, A E; Maris, T G; Zacharakis, G; Ripoll, J; Varveris, C; Damilakis, J, E-mail: apapadak@edu.med.uoc.g

    2010-11-01

    We present initial results on the comparison of the dose readout from a three dimensional polymer gel dosimeter using two different optical-CT systems; i) a common wide field and a wide area detector optical-CT system and ii) a new 'laser-line' and wide area detector based optical-CT system. The findings presented herein highlight the advantage of the laser based over the wide field optical-CT concept for the readout of scattering 3D dosimeters. Moreover, the new 'laser-line' based optical-CT system overcomes the disadvantage of the long acquisition times required by the existing laser-based instruments.

  14. Intraoperative handheld probe for 3D imaging of pediatric benign vocal fold lesions using optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Benboujja, Fouzi; Garcia, Jordan; Beaudette, Kathy; Strupler, Mathias; Hartnick, Christopher J.; Boudoux, Caroline

    2016-02-01

    Excessive and repetitive force applied on vocal fold tissue can induce benign vocal fold lesions. Children affected suffer from chronic hoarseness. In this instance, the vibratory ability of the folds, a complex layered microanatomy, becomes impaired. Histological findings have shown that lesions produce a remodeling of sup-epithelial vocal fold layers. However, our understanding of lesion features and development is still limited. Indeed, conventional imaging techniques do not allow a non-invasive assessment of sub-epithelial integrity of the vocal fold. Furthermore, it remains challenging to differentiate these sub-epithelial lesions (such as bilateral nodules, polyps and cysts) from a clinical perspective, as their outer surfaces are relatively similar. As treatment strategy differs for each lesion type, it is critical to efficiently differentiate sub-epithelial alterations involved in benign lesions. In this study, we developed an optical coherence tomography (OCT) based handheld probe suitable for pediatric laryngological imaging. The probe allows for rapid three-dimensional imaging of vocal fold lesions. The system is adapted to allow for high-resolution intra-operative imaging. We imaged 20 patients undergoing direct laryngoscopy during which we looked at different benign pediatric pathologies such as bilateral nodules, cysts and laryngeal papillomatosis and compared them to healthy tissue. We qualitatively and quantitatively characterized laryngeal pathologies and demonstrated the added advantage of using 3D OCT imaging for lesion discrimination and margin assessment. OCT evaluation of the integrity of the vocal cord could yield to a better pediatric management of laryngeal diseases.

  15. Nonlinear and quantum optics with whispering gallery resonators

    Science.gov (United States)

    Strekalov, Dmitry V.; Marquardt, Christoph; Matsko, Andrey B.; Schwefel, Harald G. L.; Leuchs, Gerd

    2016-12-01

    Optical whispering gallery modes (WGMs) derive their name from a famous acoustic phenomenon of guiding a wave by a curved boundary observed nearly a century ago. This phenomenon has a rather general nature, equally applicable to sound and all other waves. It enables resonators of unique properties attractive both in science and engineering. Very high quality factors of optical WGM resonators persisting in a wide wavelength range spanning from radio frequencies to ultraviolet light, their small mode volume, and tunable in- and out- coupling make them exceptionally efficient for nonlinear optical applications. Nonlinear optics facilitates interaction of photons with each other and with other physical systems, and is of prime importance in quantum optics. In this paper we review numerous applications of WGM resonators in nonlinear and quantum optics. We outline the current areas of interest, summarize progress, highlight difficulties, and discuss possible future development trends in these areas.

  16. Nonlinear and Quantum Optics with Whispering Gallery Resonators

    CERN Document Server

    Strekalov, Dmitry V; Matsko, Andrey B; Schwefel, Harald G L; Leuchs, Gerd

    2016-01-01

    Optical Whispering Gallery Modes (WGMs) derive their name from a famous acoustic phenomenon of guiding a wave by a curved boundary observed nearly a century ago. This phenomenon was later realized to have a rather general nature, equally applicable to sound and all other waves, but in particular also to electromagnetic waves ranging from radio frequencies to ultraviolet light. Very high quality factors of optical WGM resonators persisting in a wide wavelength range, their small mode volume, and tunable in- and out- coupling make them exceptionally efficient for nonlinear optical applications. Nonlinear optics facilitates interaction of photons with each other and with other physical systems, and is of prime importance in quantum optics. In this paper we review numerous applications of WGM resonators in nonlinear and quantum optics. We outline the current areas of interest, summarize progress, highlight difficulties, and discuss possible future development trends in these areas.

  17. Nonlinear photon-assisted tunneling transport in optical gap antennas.

    Science.gov (United States)

    Stolz, Arnaud; Berthelot, Johann; Mennemanteuil, Marie-Maxime; Colas des Francs, Gérard; Markey, Laurent; Meunier, Vincent; Bouhelier, Alexandre

    2014-05-14

    We introduce strongly coupled optical gap antennas to interface optical radiation with current-carrying electrons at the nanoscale. The transducer relies on the nonlinear optical and electrical properties of an optical gap antenna operating in the tunneling regime. We discuss the underlying physical mechanisms controlling the conversion involving d-band electrons and demonstrate that a simple two-wire optical antenna can provide advanced optoelectronic functionalities beyond tailoring the electromagnetic response of a single emitter. Interfacing an electronic command layer with a nanoscale optical device may thus be facilitated by the optical rectennas discussed here.

  18. 3D imaging of hematoxylin and eosin stained thick tissues with a sub-femtoliter resolution by using Cr:forsterite-laser-based nonlinear microscopy (Conference Presentation)

    Science.gov (United States)

    Kao, Chien-Ting; Wei, Ming-Liang; Liao, Yi-Hua; Sun, Chi-Kuang

    2017-02-01

    Intraoperative assessment of excision tissues during cancer surgery is clinically important. The assessment is used to be guided by the examination for residual tumor with frozen pathology, while it is time consuming for preparation and is with low accuracy for diagnosis. Recently, reflection confocal microscopy (RCM) and nonlinear microscopy (NLM) were demonstrated to be promising methods for surgical border assessment. Intraoperative RCM imaging may enable detection of residual tumor directly on skin cancers patients during Mohs surgery. The assessment of benign and malignant breast pathologies in fresh surgical specimens was demonstrated by NLM. Without using hematoxylin and eosin (H and E) that are common dyes for histopathological diagnosis, RCM was proposed to image in vivo by using aluminum chloride for nuclear contrast on surgical wounds directly, while NLM was proposed to detect two photon fluorescence nuclear contrast from acrdine orange staining. In this paper, we propose and demonstrate 3D imaging of H and E stained thick tissues with a sub-femtoliter resolution by using Cr:forsterite-laser-based NLM. With a 1260 nm femtosecond Cr:forsterite laser as the excitation source, the hematoxylin will strongly enhance the third-harmonic generation (THG) signals, while eosin will illuminate strong fluorescence under three photon absorption. Compared with previous works, the 1260 nm excitation light provide high penetration and low photodamage to the exercised tissues so that the possibility to perform other follow-up examination will be preserved. The THG and three-photon process provides high nonlinearity so that the super resolution in 3D is now possible. The staining and the contrast of the imaging is also fully compatible with the current clinical standard on frozen pathology thus facilitate the rapid intraoperative assessment of excision tissues. This work is sponsored by National Health Research Institutes and supported by National Taiwan University

  19. Dielectric Optical-Controllable Magnifying Lens by Nonlinear Negative Refraction

    Science.gov (United States)

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

    2015-01-01

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

  20. Extremely nonlocal optical nonlinearities in atoms trapped near a waveguide

    CERN Document Server

    Shahmoon, Ephraim; Stimming, Hans Peter; Mazets, Igor; Kurizki, Gershon

    2014-01-01

    Nonlinear optical phenomena are typically local. Here we predict the possibility of highly nonlocal optical nonlinearities for light propagating in atomic media trapped near a nano-waveguide, where long-range interactions between the atoms can be tailored. When the atoms are in an electromagnetically-induced transparency configuration, the atomic interactions are translated to long-range interactions between photons and thus to highly nonlocal optical nonlinearities. We derive and analyze the governing nonlinear propagation equation, finding a roton-like excitation spectrum for light and the emergence of long-range order in its output intensity. These predictions open the door to studies of unexplored wave dynamics and many-body physics with highly-nonlocal interactions of optical fields in one dimension.