Weijie Nie; Yuechen Jia; Vázquez de Aldana, Javier R.; Feng Chen
2016-01-01
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 ×...
Nie, Weijie; Jia, Yuechen; Vázquez de Aldana, Javier R.; Chen, Feng
2016-02-01
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.
Nie, Weijie; Jia, Yuechen; Vázquez de Aldana, Javier R; Chen, Feng
2016-01-01
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. PMID:26924255
High resolution 3D nonlinear integrated inversion
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.
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
Multiplane 3D superresolution optical fluctuation imaging
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 ...
Visualization of 3D optical lattices
Lee, Hoseong; Clemens, James
2016-05-01
We describe the visualization of 3D optical lattices based on Sisyphus cooling implemented with open source software. We plot the adiabatic light shift potentials found by diagonalizing the effective Hamiltonian for the light shift operator. Our program incorporates a variety of atomic ground state configurations with total angular momentum ranging from j = 1 / 2 to j = 4 and a variety of laser beam configurations including the two-beam lin ⊥ lin configuration, the four-beam umbrella configuration, and four beams propagating in two orthogonal planes. In addition to visualizing the lattice the program also evaluates lattice parameters such as the oscillation frequency for atoms trapped deep in the wells. The program is intended to help guide experimental implementations of optical lattices.
Handbook of 3D machine vision optical metrology and imaging
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
Nonlinear Vibrations of 3D Laminated Composite Beams
Stoykov, S; Margenov, S.
2014-01-01
A model for 3D laminated composite beams, that is, beams that can vibrate in space and experience longitudinal and torsional deformations, is derived. The model is based on Timoshenko’s theory for bending and assumes that, under torsion, the cross section rotates as a rigid body but can deform longitudinally due to warping. The warping function, which is essential for correct torsional deformations, is computed preliminarily by the finite element method. Geometrical nonlinearity is taken into...
Diffractive optical element for creating visual 3D images.
Goncharsky, Alexander; Goncharsky, Anton; Durlevich, Svyatoslav
2016-05-01
A method is proposed to compute and synthesize the microrelief of a diffractive optical element to produce a new visual security feature - the vertical 3D/3D switch effect. The security feature consists in the alternation of two 3D color images when the diffractive element is tilted up/down. Optical security elements that produce the new security feature are synthesized using electron-beam technology. Sample optical security elements are manufactured that produce 3D to 3D visual switch effect when illuminated by white light. Photos and video records of the vertical 3D/3D switch effect of real optical elements are presented. The optical elements developed can be replicated using standard equipment employed for manufacturing security holograms. The new optical security feature is easy to control visually, safely protected against counterfeit, and designed to protect banknotes, documents, ID cards, etc. PMID:27137530
The 3D solitons and vortices in 3D discrete monatomic lattices with cubic and quartic nonlinearity
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.
Optical 3-D-measurement techniques : a survey
Tiziani, Hans J.
1989-01-01
Close range photogrammetry will be more frequently applied in industry for 3-D-sensing when real time processing can be applied. Computer vision, machine vision, robot vision are in fact synonymous with real time photogrammetry. This overview paper concentrates on optical methods for 3-D-measurements. Incoherent and coherent methods for 3-D-sensing will be presented. Particular emphasis is put on high precision 3-D-measurements. Some of the work of our laboratory will be reported.
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.
Manufacturing: 3D printed micro-optics
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.
Utilization of multiple frequencies in 3D nonlinear microwave imaging
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 challenge...... 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....... arise when using data from multiple frequencies for imaging of biological targets. In this paper, the performance of a multi-frequency algorithm, in which measurement data from several different frequencies are used at once, is compared with a stepped-frequency algorithm, in which images reconstructed...
Optical experiments on 3D photonic crystals
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
Nonlinear Vibrations of 3D Laminated Composite Beams
S. Stoykov
2014-01-01
Full Text Available A model for 3D laminated composite beams, that is, beams that can vibrate in space and experience longitudinal and torsional deformations, is derived. The model is based on Timoshenko’s theory for bending and assumes that, under torsion, the cross section rotates as a rigid body but can deform longitudinally due to warping. The warping function, which is essential for correct torsional deformations, is computed preliminarily by the finite element method. Geometrical nonlinearity is taken into account by considering Green’s strain tensor. The equation of motion is derived by the principle of virtual work and discretized by the p-version finite element method. The laminates are assumed to be of orthotropic materials. The influence of the angle of orientation of the laminates on the natural frequencies and on the nonlinear modes of vibration is presented. It is shown that, due to asymmetric laminates, there exist bending-longitudinal and bending-torsional coupling in linear analysis. Dynamic responses in time domain are presented and couplings between transverse displacements and torsion are investigated.
Three-Dimensional Optical Coherence Tomography (3D OCT) Project
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...
Three-Dimensional Optical Coherence Tomography (3D OCT) Project
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...
Optical characterization and measurements of autostereoscopic 3D displays
Salmimaa, Marja; Järvenpää, Toni
2008-04-01
3D or autostereoscopic display technologies offer attractive solutions for enriching the multimedia experience. However, both characterization and comparison of 3D displays have been challenging when the definitions for the consistent measurement methods have been lacking and displays with similar specifications may appear quite different. Earlier we have investigated how the optical properties of autostereoscopic (3D) displays can be objectively measured and what are the main characteristics defining the perceived image quality. In this paper the discussion is extended to cover the viewing freedom (VF) and the definition for the optimum viewing distance (OVD) is elaborated. VF is the volume inside which the eyes have to be to see an acceptable 3D image. Characteristics limiting the VF space are proposed to be 3D crosstalk, luminance difference and color difference. Since the 3D crosstalk can be presumed to be dominating the quality of the end user experience and in our approach is forming the basis for the calculations of the other optical parameters, the reliability of the 3D crosstalk measurements is investigated. Furthermore the effect on the derived VF definition is evaluated. We have performed comparison 3D crosstalk measurements with different measurement device apertures and the effect of different measurement geometry on the results on actual 3D displays is reported.
Parallel Processor for 3D Recovery from Optical Flow
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.
A 3D Optical Metamaterial Made by Self-Assembly
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.
Flexydos3D: A new deformable anthropomorphic 3D dosimeter readout with optical CT scanning
A new deformable polydimethylsiloxane (PDMS) based dosimeter is proposed that can be cast in an anthropomorphic shape and that can be used for 3D radiation dosimetry of deformable targets. The new material has additional favorable characteristics as it is tissue equivalent for high-energy photons, easy to make and is non-toxic. In combination with dual wavelength optical scanning, it is a powerful dosimeter for dose verification of image gated or organ tracked radiotherapy with moving and deforming targets
Nonlinear Optics and Applications
Abdeldayem, Hossin A. (Editor); Frazier, Donald O. (Editor)
2007-01-01
Nonlinear optics is the result of laser beam interaction with materials and started with the advent of lasers in the early 1960s. The field is growing daily and plays a major role in emerging photonic technology. Nonlinear optics play a major role in many of the optical applications such as optical signal processing, optical computers, ultrafast switches, ultra-short pulsed lasers, sensors, laser amplifiers, and many others. This special review volume on Nonlinear Optics and Applications is intended for those who want to be aware of the most recent technology. This book presents a survey of the recent advances of nonlinear optical applications. Emphasis will be on novel devices and materials, switching technology, optical computing, and important experimental results. Recent developments in topics which are of historical interest to researchers, and in the same time of potential use in the fields of all-optical communication and computing technologies, are also included. Additionally, a few new related topics which might provoke discussion are presented. The book includes chapters on nonlinear optics and applications; the nonlinear Schrodinger and associated equations that model spatio-temporal propagation; the supercontinuum light source; wideband ultrashort pulse fiber laser sources; lattice fabrication as well as their linear and nonlinear light guiding properties; the second-order EO effect (Pockels), the third-order (Kerr) and thermo-optical effects in optical waveguides and their applications in optical communication; and, the effect of magnetic field and its role in nonlinear optics, among other chapters.
Fiber optic coherent laser radar 3D vision system
Clark, R.B.; Gallman, P.G.; Slotwinski, A.R. [Coleman Research Corp., Springfield, VA (United States); Wagner, K.; Weaver, S.; Xu, Jieping [Colorado Univ., Boulder, CO (United States)
1996-12-31
This CLVS will provide a substantial advance in high speed computer vision performance to support robotic Environmental Management (EM) operations. This 3D system employs a compact fiber optic based scanner and operator at a 128 x 128 pixel frame at one frame per second with a range resolution of 1 mm over its 1.5 meter working range. Using acousto-optic deflectors, the scanner is completely randomly addressable. This can provide live 3D monitoring for situations where it is necessary to update once per second. This can be used for decontamination and decommissioning operations in which robotic systems are altering the scene such as in waste removal, surface scarafacing, or equipment disassembly and removal. The fiber- optic coherent laser radar based system is immune to variations in lighting, color, or surface shading, which have plagued the reliability of existing 3D vision systems, while providing substantially superior range resolution.
Fiber optic coherent laser radar 3D vision system
This CLVS will provide a substantial advance in high speed computer vision performance to support robotic Environmental Management (EM) operations. This 3D system employs a compact fiber optic based scanner and operator at a 128 x 128 pixel frame at one frame per second with a range resolution of 1 mm over its 1.5 meter working range. Using acousto-optic deflectors, the scanner is completely randomly addressable. This can provide live 3D monitoring for situations where it is necessary to update once per second. This can be used for decontamination and decommissioning operations in which robotic systems are altering the scene such as in waste removal, surface scarafacing, or equipment disassembly and removal. The fiber- optic coherent laser radar based system is immune to variations in lighting, color, or surface shading, which have plagued the reliability of existing 3D vision systems, while providing substantially superior range resolution
3D optical manipulation of a single electron spin
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.
Automatic respiration tracking for radiotherapy using optical 3D camera
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
3D optical measuring technologies for dimensional inspection
The results of the R and D activity of TDI SIE SB RAS in the field of the 3D optical measuring technologies and systems for noncontact 3D optical dimensional inspection applied to atomic and railway industry safety problems are presented. This activity includes investigations of diffraction phenomena on some 3D objects, using the original constructive calculation method, development of hole inspection method on the base of diffractive optical elements. Ensuring the safety of nuclear reactors and running trains as well as their high exploitation reliability takes a noncontact inspection of geometrical parameters of their components. For this tasks we have developed methods and produced the technical vision measuring systems LMM, CONTROL, PROFILE, and technologies for non-contact 3D dimensional inspection of grid spacers and fuel elements for the nuclear reactor VVER-1000 and VVER-440, as well as automatic laser diagnostic system COMPLEX for noncontact inspection of geometrical parameters of running freight car wheel pairs. The performances of these systems and the results of the industrial testing at atomic and railway companies are presented
Implementation of 3D Optical Scanning Technology for Automotive Applications.
Kuş, Abdil
2009-01-01
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. PMID:22573995
Constructing 3D microtubule networks using holographic optical trapping
Bergman, J.; Osunbayo, O.; Vershinin, M.
2015-01-01
Developing abilities to assemble nanoscale structures is a major scientific and engineering challenge. We report a technique which allows precise positioning and manipulation of individual rigid filaments, enabling construction of custom-designed 3D filament networks. This approach uses holographic optical trapping (HOT) for nano-positioning and microtubules (MTs) as network building blocks. MTs are desirable engineering components due to their high aspect ratio, rigidity, and their ability t...
Open-source 3D-printable optics equipment.
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.
Fiber optic coherent laser radar 3d vision system
Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic of coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system
Fiber optic coherent laser radar 3d vision system
Sebastian, R.L.; Clark, R.B.; Simonson, D.L. [and others
1994-12-31
Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic of coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.
3D Human cartilage surface characterization by optical coherence tomography
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
Simulation of Fully Nonlinear 3-D Numerical Wave Tank
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.
Distributed nonlinear optical response
Nikolov, Nikola Ivanov
2005-01-01
. The research presented in Chapter 3 and papers B and C is concerned with the properties and the stable dark soliton propagation and their bound states in nonlocal nonlinear optical media. It is shown that nonlocality of the nonlinearity induces attractive forces between solitons, that leads to the...... formation of bound states of out of phase bright solitons and dark solitons. Also, the newly introduced analogy between the nonlocal cubic nonlinear and the quadratic nonlinear media, presented in paper B and Chapter 3 is discussed. In particular it supplies intuitive physical meaning of the formation of...
Nonlinear optics at interfaces
Chen, C.K.
1980-12-01
Two aspects of surface nonlinear optics are explored in this thesis. The first part is a theoretical and experimental study of nonlinear intraction of surface plasmons and bulk photons at metal-dielectric interfaces. The second part is a demonstration and study of surface enhanced second harmonic generation at rough metal surfaces. A general formulation for nonlinear interaction of surface plasmons at metal-dielectric interfaces is presented and applied to both second and third order nonlinear processes. Experimental results for coherent second and third harmonic generation by surface plasmons and surface coherent antiStokes Raman spectroscopy (CARS) are shown to be in good agreement with the theory.
Large Scale 3D Image Reconstruction in Optical Interferometry
Schutz, Antony; Mary, David; Thiébaut, Eric; Soulez, Ferréol
2015-01-01
Astronomical optical interferometers (OI) sample the Fourier transform of the intensity distribution of a source at the observation wavelength. Because of rapid atmospheric perturbations, the phases of the complex Fourier samples (visibilities) cannot be directly exploited , and instead linear relationships between the phases are used (phase closures and differential phases). Consequently, specific image reconstruction methods have been devised in the last few decades. Modern polychromatic OI instruments are now paving the way to multiwavelength imaging. This paper presents the derivation of a spatio-spectral ("3D") image reconstruction algorithm called PAINTER (Polychromatic opticAl INTErferometric Reconstruction software). The algorithm is able to solve large scale problems. It relies on an iterative process, which alternates estimation of polychromatic images and of complex visibilities. The complex visibilities are not only estimated from squared moduli and closure phases, but also from differential phase...
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...
A nonlinear 3D containment analysis for airplane impact
In the Federal Republic of Germany, it is pertinent safety philosophy to design nuclear facilities against airplane impact, despite its very unlikely probability of occurrence. For safety reasons, the following conditions have to be met: 1) In the close impact area of the projectile, the structure can be stressed up to its ultimate load capacity, so that impact energy is dissipated partly. Hereby, it must be strictly clarified that local structural failure within the impact zone is avoided. 2) Residual impact energy is transferred to the 'non-disturbed' containment structure and to the interior structure. The subject of reinforced concrete structures under impact loads shows still clear gaps between the findings of experimental and analytical analyses. To clarify this highly nonlinear phenomena comprehensive tests have recently been performed in Germany. It is the aim of this paper to carry out a three-dimensional analysis of a nuclear facility. To perform the calculations, the finite element ADINA code is applied. In order to obtain optimum results, a very fine mesh leading to several thousand DOF is used. To model the impact area of the concrete structure realistically, its linear and mostly nonlinear material behaviour as well as its failure criteria must be taken into account. Herewith the structural response is reduced due to increased energy dissipation. This reduction rate is valued by variation of the assumed size of impact zone, the load impact location and the assumed load-time function. (orig./RW)
Precision 3-D microscopy with intensity modulated fibre optic scanners
Olmos, P.
2016-01-01
Optical 3-D imagers constitute a family of precision and useful instruments, easily available on the market in a wide variety of configurations and performances. However, besides their cost they usually provide an image of the object (i.e. a more or less faithful representation of the reality) instead of a truly object's reconstruction. Depending on the detailed working principles of the equipment, this reconstruction may become a challenging task. Here a very simple yet reliable device is described; it is able to form images of opaque objects by illuminating them with an optical fibre and collecting the reflected light with another fibre. Its 3-D capability comes from the spatial filtering imposed by the fibres together with their movement (scanning) along the three directions: transversal (surface) and vertical. This unsophisticated approach allows one to model accurately the entire optical process and to perform the desired reconstruction, finding that information about the surface which is of interest: its profile and its reflectance, ultimately related to the type of material.
Nonlinear effects in optical fibers
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
3D OPTICAL AND IR SPECTROSCOPY OF EXCEPTIONAL HII GALAXIES
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.
Non-linear correction for accuracy improvement of the neutron calculations with HEXAB-3D Code
A differential approach of application of the Improved Coarse Mesh Method in the 3D hexagonal geometry diffusion problem is presented. A non-linear nodal model of improvement based on the solution of the local balance equation in a triangular sub-region of the node with triple decreased mesh step and a presentation of the spatial distribution of the neutron flux by linear combination of trigonometric al hyperbolic functions are presented. A principal program realisation of the differential nonlinear correction in the hexagonal geometry diffusion code HEXA-B-3D is described. Benchmark results for a 3D WWER-1000 benchmark problem are presented
3D refractive index measurements of special optical fibers
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.
An efficient flexible-order model for 3D nonlinear water waves
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...
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...
Quantitative 3D Optical Imaging: Applications in Dosimetry and Biophysics
Thomas, Andrew Stephen
Optical-CT has been shown to be a potentially useful imaging tool for the two very different spheres of biologists and radiation therapy physicists, but it has yet to live up to that potential. In radiation therapy, researchers have used optical-CT for the readout of 3D dosimeters, but it is yet to be a clinically relevant tool as the technology is too slow to be considered practical. Biologists have used the technique for structural imaging, but have struggled with emission tomography as the reality of photon attenuation for both excitation and emission have made the images quantitatively irrelevant. Dosimetry. The DLOS (Duke Large field of view Optical-CT Scanner) was designed and constructed to make 3D dosimetry utilizing optical-CT a fast and practical tool while maintaining the accuracy of readout of the previous, slower readout technologies. Upon construction/optimization/implementation of several components including a diffuser, band pass filter, registration mount & fluid filtration system the dosimetry system provides high quality data comparable to or exceeding that of commercial products. In addition, a stray light correction algorithm was tested and implemented. The DLOS in combination with the 3D dosimeter it was designed for, PREAGETM, then underwent rigorous commissioning and benchmarking tests validating its performance against gold standard data including a set of 6 irradiations. DLOS commissioning tests resulted in sub-mm isotropic spatial resolution (MTF >0.5 for frequencies of 1.5lp/mm) and a dynamic range of ˜60dB. Flood field uniformity was 10% and stable after 45minutes. Stray light proved to be small, due to telecentricity, but even the residual can be removed through deconvolution. Benchmarking tests showed the mean 3D passing gamma rate (3%, 3mm, 5% dose threshold) over the 6 benchmark data sets was 97.3% +/- 0.6% (range 96%-98%) scans totaling ˜10 minutes, indicating excellent ability to perform 3D dosimetry while improving the speed of
Nonlinear Optical Properties of Materials
Ganeev, Rashid A
2013-01-01
This book is mostly concerned on the experimental research of the nonlinear optical characteristics of various media, low- and high-order harmonic generation in different materials, and formation, and nonlinear optical characterization of clusters. We also demonstrate the inter-connection between these areas of nonlinear optics. Nonlinear optical properties of media such as optical limiting can be applied in various areas of science and technology. To define suitable materials for these applications, one has to carefully analyse the nonlinear optical characteristics of various media, such as the nonlinear refractive indices, coefficients of nonlinear absorption, saturation absorption intensities, etc. Knowing the nonlinear optical parameters of materials is also important for describing the propagation effects, self-interaction of intense laser pulses, and optimisation of various nonlinear optical processes. Among those processes one can admit the importance of the studies of the frequency conversion of c...
3D parameter reconstruction in hyperspectral diffuse optical tomography
Saibaba, Arvind K.; Krishnamurthy, Nishanth; Anderson, Pamela G.; Kainerstorfer, Jana M.; Sassaroli, Angelo; Miller, Eric L.; Fantini, Sergio; Kilmer, Misha E.
2015-03-01
The imaging of shape perturbation and chromophore concentration using Diffuse Optical Tomography (DOT) data can be mathematically described as an ill-posed and non-linear inverse problem. The reconstruction algorithm for hyperspectral data using a linearized Born model is prohibitively expensive, both in terms of computation and memory. We model the shape of the perturbation using parametric level-set approach (PaLS). We discuss novel computational strategies for reducing the computational cost based on a Krylov subspace approach for parameteric linear systems and a compression strategy for the parameter-to-observation map. We will demonstrate the validity of our approach by comparison with experiments.
Parsing optical scanned 3D data by Bayesian inference
Xiong, Hanwei; Xu, Jun; Xu, Chenxi; Pan, Ming
2015-10-01
Optical devices are always used to digitize complex objects to get their shapes in form of point clouds. The results have no semantic meaning about the objects, and tedious process is indispensable to segment the scanned data to get meanings. The reason for a person to perceive an object correctly is the usage of knowledge, so Bayesian inference is used to the goal. A probabilistic And-Or-Graph is used as a unified framework of representation, learning, and recognition for a large number of object categories, and a probabilistic model defined on this And-Or-Graph is learned from a relatively small training set per category. Given a set of 3D scanned data, the Bayesian inference constructs a most probable interpretation of the object, and a semantic segment is obtained from the part decomposition. Some examples are given to explain the method.
Terahertz semiconductor nonlinear optics
Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias
2013-01-01
In this proceedings we describe our recent results on semiconductor nonlinear optics, investigated using single-cycle THz pulses. We demonstrate the nonlinear absorption and self-phase modulation of strong-field THz pulses in doped semiconductors, using n-GaAs as a model system. The THz...... 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 to a...... decrease of plasma frequency in semiconductor and produces a substantial modification of THz-range material dielectric function, described by the Drude model. As a result, the nonlinearity of both absorption coefficient and refractive index of the semiconductor is observed. In particular we demonstrate the...
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
Adaptive control of nonlinear visual servoing systems for 3D cartesian tracking
Alessandro R. L. Zachi
2006-12-01
Full Text Available This paper presents a control strategy for robot manipulators to perform 3D cartesian tracking using visual servoing. Considering a fixed camera, the 3D cartesian motion is decomposed in a 2D motion on a plane orthogonal to the optical axis and a 1D motion parallel to this axis. An image-based visual servoing approach is used to deal with the nonlinear control problem generated by the depth variation without requiring direct depth estimation. Due to the lack of camera calibration, an adaptive control method is used to ensure both depth and planar tracking in the image frame. The depth feedback loop is closed by measuring the image area of a target object attached to the robot end-effector. Simulation and experimental results obtained with a real robot manipulator illustrate the viability of the proposed scheme.Este trabalho apresenta uma estratégia de controle para robôs manipuladores realizarem rastreamento cartesiano 3D utilizando servovisão. Considerando uma câmera fixa, o movimento cartesiano 3D é decomposto em um movimento 2D sobre um plano ortogonal ao eixo óptico e em outro movimento 1D paralelo ao mesmo eixo. Uma abordagem de servovisão baseada em imagem é utilizada para tratar o problema de controle não-linear, gerado pela variação de profundidade, sem a necessidade de estimar esta medida. Devido à ausência de calibração da câmera, um método de controle adaptativo é utilizado para assegurar rastreamento planar e de profundidade nas coordenadas da imagem. A malha de controle de profundidade é fechada através da medição da área da imagem de um objeto fixado no efetuador do robô. Simulação e resultados experimentais, obtidos com um robô manipulador real, ilustram a viabilidade do esquema proposto.
Essentials of nonlinear optics
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.
Nonlinear fibre optics overview
Travers, J. C.; Frosz, Michael Henoch; Dudley, J. M.
2010-01-01
The optical fiber based supercontinuum source has recently become a significant scientific and commercial success, with applications ranging from frequency comb production to advanced medical imaging. This one-of-a-kind book explains the theory of fiber supercontinuum broadening, describes the......, 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 to...
High-order finite difference solution for 3D nonlinear wave-structure interaction
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...
Cordless hand-held optical 3D sensor
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.
Magneto-acoustic waves in sunspots: first results from a new 3D nonlinear magnetohydrodynamic code
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...
Terahertz Nonlinear Optics in Semiconductors
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...... breathing of a single-cycle THz pulse in a semiconductor....
We report nonlinear multiphoton processes in atoms and molecules by intense high harmonics and their applications to attosecond pulse characterization. Phase matched high harmonics by a loosely focusing geometry produce highly focusable intensity with fully spatiotemporal coherence, which is sufficient to induce nonlinear optical phenomena in the extreme ultraviolet and soft x-ray (XUV) region. With this XUV coherent light source, two-photon double ionization in He is demonstrated with 42-eV high harmonic photons. On the other hand, when intense high harmonics around 20 eV is subjected to N2 molecules, occurrence of Coulomb explosion following to two-photon double ionization is observed in attosecond temporal precision. Taking advantage of larger cross section of two-photon ionization in molecules, we successfully perform the interferometric autocorrelation of an attosecond pulse train with the ion signals produced by Coulomb explosion of nitrogen molecules. The result reveals the phase relation between attosecond pulses in the train.
Segmentation of the Optic Disc in 3-D OCT Scans of the Optic Nerve Head
Lee, Kyungmoo; Niemeijer, Meindert; Garvin, Mona K.; Kwon, Young H.; Sonka, Milan; Abràmoff, Michael D.
2009-01-01
Glaucoma is the second leading ocular disease causing blindness due to gradual damage to the optic nerve and resultant visual field loss. Segmentations of the optic disc cup and neuroretinal rim can provide important parameters for detecting and tracking this disease. The purpose of this study is to describe and evaluate a method that can automatically segment the optic disc cup and rim in spectral-domain 3-D OCT (SD-OCT) volumes. Four intraretinal surfaces were segmented using a fast multisc...
Frequency domain nonlinear optics
Legare, Francois
2016-05-01
The universal dilemma of gain narrowing occurring in fs amplifiers prevents ultra-high power lasers from delivering few-cycle pulses. This problem is overcome by a new amplification concept: Frequency domain Optical Parametric Amplification - FOPA. It enables simultaneous up-scaling of peak power and amplified spectral bandwidth and can be performed at any wavelength range of conventional amplification schemes, however, with the capability to amplify single cycles of light. The key idea for amplification of octave-spanning spectra without loss of spectral bandwidth is to amplify the broad spectrum ``slice by slice'' in the frequency domain, i.e. in the Fourier plane of a 4f-setup. The striking advantages of this scheme, are its capability to amplify (more than) one octave of bandwidth without shorting the corresponding pulse duration. This is because ultrabroadband phase matching is not defined by the properties of the nonlinear crystal employed but the number of crystals employed. In the same manner, to increase the output energy one simply has to increase the spectral extension in the Fourier plane and to add one more crystal. Thus, increasing pulse energy and shortening its duration accompany each other. A proof of principle experiment was carried out at ALLS on the sub-two cycle IR beam line and yielded record breaking performance in the field of few-cycle IR lasers. 100 μJ two-cycle pulses from a hollow core fibre compression setup were amplified to 1.43mJ without distorting spatial or temporal properties. Pulse duration at the input of FOPA and after FOPA remains the same. Recently, we have started upgrading this system to be pumped by 250 mJ to reach 40 mJ two-cycle IR few-cycle pulses and latest results will be presented at the conference. Furthermore, the extension of the concept of FOPA to other nonlinear optical processes will be discussed. Frequency domain nonlinear optics.
Nonlinear Optical Terahertz Technology Project
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...
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.
Nonlinear Optics: Principles and Applications
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...... nonlinear phenomena, it describes nonlinear wave propagation in bulk and in waveguiding structures, and includes specific examples of applied nonlinear wave propagation through crystals, optical waveguides, and optical fibers. Providing a theoretical description of nonlinear interaction between light and...
Air-structured optical fibre drawn from a 3D-printed preform
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.
Nonlinear dynamics of Airy-Vortex 3D wave packets: Emission of vortex light waves
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.
Optical 3D watermark based digital image watermarking for telemedicine
Li, Xiao Wei; Kim, Seok Tae
2013-12-01
Region of interest (ROI) of a medical image is an area including important diagnostic information and must be stored without any distortion. This algorithm for application of watermarking technique for non-ROI of the medical image preserving ROI. The paper presents a 3D watermark based medical image watermarking scheme. In this paper, a 3D watermark object is first decomposed into 2D elemental image array (EIA) by a lenslet array, and then the 2D elemental image array data is embedded into the host image. The watermark extraction process is an inverse process of embedding. The extracted EIA through the computational integral imaging reconstruction (CIIR) technique, the 3D watermark can be reconstructed. Because the EIA is composed of a number of elemental images possesses their own perspectives of a 3D watermark object. Even though the embedded watermark data badly damaged, the 3D virtual watermark can be successfully reconstructed. Furthermore, using CAT with various rule number parameters, it is possible to get many channels for embedding. So our method can recover the weak point having only one transform plane in traditional watermarking methods. The effectiveness of the proposed watermarking scheme is demonstrated with the aid of experimental results.
A 3D DISCRETE DUALITY FINITE VOLUME METHOD FOR NONLINEAR ELLIPTIC EQUATIONS
Coudière, Yves; Hubert, Florence
2009-01-01
Discrete Duality Finite Volume (DDFV) schemes have recently been developed in 2D to approximate nonlinear diﬀusion problems on general meshes. In this paper, a 3D extension of these schemes is proposed. The construction of this extension is detailed and its main properties are proved: a priori bounds, well-posedness and error estimates. The practical implementation of this scheme is easy. Numerical experiments are presented to illustrate its good behavior.
Neutron radiographic image restoration using BM3D frames and nonlinear variance stabilization
Shuang, Qiao; Wei-jing, Zhao; Jia-ning, Sun
2015-07-01
Neutron radiography is a powerful tool for non-destructive investigations in industrial applications. However, the resulting images are degraded inevitably due to some physical limitations. In this paper, we propose a new scheme for neutron image restoration, which utilizes BM3D frames and nonlinear variance stabilization including generalized anscombe transformation and its exact unbiased inverse. Experimental results show that superior to the existing restoration methods, the proposed scheme improves the restoration quality efficiently and exhibits better visual results.
Toward high-speed 3D nonlinear soft tissue deformation simulations using Abaqus software.
Idkaidek, Ashraf; Jasiuk, Iwona
2015-12-01
We aim to achieve a fast and accurate three-dimensional (3D) simulation of a porcine liver deformation under a surgical tool pressure using the commercial finite element software Abaqus. The liver geometry is obtained using magnetic resonance imaging, and a nonlinear constitutive law is employed to capture large deformations of the tissue. Effects of implicit versus explicit analysis schemes, element type, and mesh density on computation time are studied. We find that Abaqus explicit and implicit solvers are capable of simulating nonlinear soft tissue deformations accurately using first-order tetrahedral elements in a relatively short time by optimizing the element size. This study provides new insights and guidance on accurate and relatively fast nonlinear soft tissue simulations. Such simulations can provide force feedback during robotic surgery and allow visualization of tissue deformations for surgery planning and training of surgical residents. PMID:26530842
Focus issue introduction: nonlinear optics 2013.
Dadap, J. I.; Karlsson, M.; Panoiu, N. C.
2013-01-01
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.
A stabilized complementarity formulation for nonlinear analysis of 3D bimodular materials
Zhang, L.; Zhang, H. W.; Wu, J.; Yan, B.
2015-10-01
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.
A stabilized complementarity formulation for nonlinear analysis of 3D bimodular materials
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.
Verification of 3D heterogeneous core transport calculation utilizing non-linear iteration technique
A three dimensional heterogeneous core transport analysis code CHAPLET-3D, which is based on deterministic methods, has been developed. In CHAPLET-3D code, the non-linear iteration technique, which is commonly used in advanced nodal diffusion codes, is employed to perform three dimensional heterogeneous core calculation in form of conventional finite difference method with the accuracy of the method of characteristics in radial two dimensional geometry. For an axial direction solver, in addition to finite difference method and nodal expansion method in diffusion theory, the method of characteristics has been incorporated in order to take account of transport effect. According to the verification tests compared with the results of multi-group Monte Carlo reference calculations, it is found that the accuracy of CHAPLET-3D code for three dimensional heterogeneous core analysis is almost the same level as that of the reference calculation and also demonstrated that the three dimensional core analysis method utilizing the non-linear iteration technique introduced here is valid and useful. (author)
PRONTO3D users` instructions: A transient dynamic code for nonlinear structural analysis
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.
Characterizing the propagation of gravity waves in 3D nonlinear simulations of solar-like stars
Alvan, L.; Strugarek, A.; Brun, A. S.; Mathis, S.; Garcia, R. A.
2015-09-01
Context. 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. Aims: 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. Methods: We use a method of frequency filtering that reveals the path of individual gravity waves of different frequencies in the radiative zone. Results: 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 different planes in the sphere, depending on their azimuthal wave number. Conclusions: We are able to isolate individual IGWs from a complex spectrum and to study their propagation in space and time. In particular, we highlight in this paper the necessity of studying the propagation of waves in 3D spherical geometry, since the distribution of their energy is not equipartitioned in the sphere.
Toward a scalable flexible-order model for 3D nonlinear water waves
Engsig-Karup, Allan Peter; Ducrozet, Guillaume; Bingham, Harry B.;
For marine and coastal applications, current work are directed toward the development of a scalable numerical 3D model for fully nonlinear potential water waves over arbitrary depths. The model is high-order accurate, robust and efficient for large-scale problems, and support will be included for...... flexibility in the description of structures by the use of curvilinear boundary-fitted meshes. The mathematical equations for potential waves in the physical domain is transformed through $\\sigma$-mapping(s) to a time-invariant boundary-fitted domain which then becomes a basis for an efficient solution...
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...
Haupert, Levi M.; Simpson, Garth J.
2009-05-01
The past decade has witnessed the emergence of new measurement approaches and applications for chiral thin films and materials enabled by the observations of the high sensitivity of second-order nonlinear optical measurements to chirality. In thin films, the chiral response to second harmonic generation and sum frequency generation (SFG) from a single molecular monolayer is often comparable with the achiral response. The chiral specificity also allows for symmetry-allowed SFG in isotropic chiral media, confirming predictions made ˜50 years ago. With these experimental demonstrations in hand, an important challenge is the construction of intuitive predictive models that allow the measured chiral response to be meaningfully related back to molecular and macromolecular structure. This review defines and considers three distinct mechanisms for chiral effects in uniaxially oriented assemblies: orientational chirality, intrinsic chirality, and isotropic chirality. The role of each is discussed in experimental and computational studies of bacteriorhodopsin films, binaphthol, and collagen. Collectively, these three model systems support a remarkably simple framework for quantitatively recovering the measured chiral-specific activity.
Step-index optical fibre drawn from 3D printed preforms
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.
Characterizing the propagation of gravity waves in 3D nonlinear simulations of solar-like stars
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...
3-D Adaptive Sparsity Based Image Compression With Applications to Optical Coherence Tomography.
Fang, Leyuan; Li, Shutao; Kang, Xudong; Izatt, Joseph A; Farsiu, Sina
2015-06-01
We present a novel general-purpose compression method for tomographic images, termed 3D adaptive sparse representation based compression (3D-ASRC). In this paper, we focus on applications of 3D-ASRC for the compression of ophthalmic 3D optical coherence tomography (OCT) images. The 3D-ASRC algorithm exploits correlations among adjacent OCT images to improve compression performance, yet is sensitive to preserving their differences. Due to the inherent denoising mechanism of the sparsity based 3D-ASRC, the quality of the compressed images are often better than the raw images they are based on. Experiments on clinical-grade retinal OCT images demonstrate the superiority of the proposed 3D-ASRC over other well-known compression methods. PMID:25561591
Wang, Guo-Zhen; Huang, Yi-Pai; Hu, Kuo-Jui
2012-06-01
We proposed a virtual 3D-touch system by bare finger, which can detect the 3-axis (x, y, z) information of finger. This system has multi-wavelength optical sensor array embedded on the backplane of TFT panel and sequentail devices on the border of TFT panel. We had developed reflecting mode which can be worked by bare finger for the 3D interaction. A 4-inch mobile 3D-LCD with this proposed system was successfully been demonstrated already.
DETERMINATION OF INTERNAL STRAIN IN 3-D BRAIDED COMPOSITES USING OPTIC FIBER STRAIN SENSORS
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.
Optic flow-based vision system for autonomous 3D localization and control of small aerial vehicles
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-reso...
Nonlinear optics of matter waves
Goldstein, E. V.; Moore, M. G.; Zobay, O.; Meystre, P.
1998-01-01
We give a brief overview of the way atomic physics is now developing in a way reminiscent of the optics revolution of the 1960's. Thanks in particular to recent developments in atomic trapping and cooling, the new field of atom optics is rapidly leading to exciting new developments such as nonlinear atom optics and quantum atom optics. We illustrate these developments with examples out of our own research.
Wakayama, Koji; Okuno, Michitaka; Matsuoka, Yasunobu; Hosomi, Kazuhiko; Sagawa, Misuzu; Sugawara, Toshiki
2009-11-01
We propose an optical switch control procedure for high-performance and cost-effective 10 Gbps Active Optical Access System (AOAS) in which optical switches are used instead of optical splitters in PON (Passive Optical Network). We demonstrate the implemented optical switch control module on Optical Switching Unit (OSW) with logic circuits works effectively. We also propose a compact optical 3D-CSP (Chip Scale Package) to achieve the high performance of AOAS without losing cost advantage of PON. We demonstrate the implemented 3D-CSP works effectively.
Oscillating solitons in nonlinear optics
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.
Long-lived dipolar molecules and Feshbach molecules in a 3D optical lattice
Chotia, Amodsen; Moses, Steven A; Yan, Bo; Covey, Jacob P; Foss-Feig, Michael; Rey, Ana Maria; Jin, Deborah S; Ye, Jun
2011-01-01
We have realized long-lived ground-state polar molecules in a 3D optical lattice, with a lifetime of up to 25 s, which is limited only by off-resonant scattering of the trapping light. Starting from a 2D optical lattice, we observe that the lifetime increases dramatically as a small lattice potential is added along the tube-shaped lattice traps. The 3D optical lattice also dramatically increases the lifetime for weakly bound Feshbach molecules. For a pure gas of Feshbach molecules, we observe a lifetime of >20 s in a 3D optical lattice; this represents a 100-fold improvement over previous results. This lifetime is also limited by off-resonant scattering, the rate of which is related to the size of the Feshbach molecule. Individually trapped Feshbach molecules in the 3D lattice can be converted to pairs of K and Rb atoms and back with nearly 100% efficiency.
An optical real-time 3D measurement for analysis of facial shape and movement
Zhang, Qican; Su, Xianyu; Chen, Wenjing; Cao, Yiping; Xiang, Liqun
2003-12-01
Optical non-contact 3-D shape measurement provides a novel and useful tool for analysis of facial shape and movement in presurgical and postsurgical regular check. In this article we present a system, which allows a precise 3-D visualization of the patient's facial before and after craniofacial surgery. We discussed, in this paper, the real time 3-D image capture, processing and the 3-D phase unwrapping method to recover complex shape deformation when the movement of the mouth. The result of real-time measurement for facial shape and movement will be helpful for the more ideal effect in plastic surgery.
Liang-Chia Chen; Manh-Trung Le; Xuan-Loc Nguyen
2012-01-01
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 effe...
Advanced 3D-reconstruction of biological specimen monitored by non-invasive optical tomography
Imaging of intricate and delicate subcellular structures along with reliable 3D-reconstruction of cells and tissues may be achieved on the basis of confocal laser scanning microscopy (optical tomography) provided that certain criteria such as proper loading of fluorescent dyes, image acquisition under defined electro-optical conditions, suitable image pre- and postprocessing, etc., are taken into account prior to volume- or surface-rendering for 3D-visualization. (author)
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.
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
3D Nonlinear Numerical Simulation of Intact and Debonded Reinforced Concrete Beams
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.
Neutron radiographic image restoration using BM3D frames and nonlinear variance stabilization
Neutron radiography is a powerful tool for non-destructive investigations in industrial applications. However, the resulting images are degraded inevitably due to some physical limitations. In this paper, we propose a new scheme for neutron image restoration, which utilizes BM3D frames and nonlinear variance stabilization including generalized anscombe transformation and its exact unbiased inverse. Experimental results show that superior to the existing restoration methods, the proposed scheme improves the restoration quality efficiently and exhibits better visual results. - Highlights: • Aiming at the degradation features of neutron radiographic images, we propose a novel theoretic restoration model. • According to the restoration model, an explicit algorithm is also presented. • The practical feasibility of the new scheme is verified through some experiments on real neutron radiographic images and standard testing image
Neutron radiographic image restoration using BM3D frames and nonlinear variance stabilization
Shuang, Qiao; Wei-jing, Zhao [School of Physics, Northeast Normal University, Changchun (China); Jia-ning, Sun, E-mail: sunjn118@nenu.edu.cn [School of Mathematics and Statistics, Northeast Normal University, Changchun (China)
2015-07-21
Neutron radiography is a powerful tool for non-destructive investigations in industrial applications. However, the resulting images are degraded inevitably due to some physical limitations. In this paper, we propose a new scheme for neutron image restoration, which utilizes BM3D frames and nonlinear variance stabilization including generalized anscombe transformation and its exact unbiased inverse. Experimental results show that superior to the existing restoration methods, the proposed scheme improves the restoration quality efficiently and exhibits better visual results. - Highlights: • Aiming at the degradation features of neutron radiographic images, we propose a novel theoretic restoration model. • According to the restoration model, an explicit algorithm is also presented. • The practical feasibility of the new scheme is verified through some experiments on real neutron radiographic images and standard testing image.
Integrated gravity and gravity gradient 3D inversion using the non-linear conjugate gradient
Qin, Pengbo; Huang, Danian; Yuan, Yuan; Geng, Meixia; Liu, Jie
2016-03-01
Gravity data, which are critical in mineral, oil, and gas exploration, are obtained from the vertical component of the gravity field, while gravity gradient data are measured from changes in the gravity field in three directions. However, few studies have sought to improve exploration techniques by integrating gravity and gravity gradient data using inversion methods. In this study, we developed a new method to integrate gravity and gravity gradient data in a 3D density inversion using the non-linear conjugate gradient (NLCG) method and the minimum gradient support (MGS) functional to regularize the 3D inverse problem and to obtain a clear and accurate image of the anomalous body. The NLCG algorithm, which is suitable for solving large-scale nonlinear optimization problems and requires no memory storage, was compared to the Broyden-Fletcher-Goldfarb-Shanno (BFGS) quasi-Newton algorithm and the results indicated that the convergence rate of NLCG is slower, but that the storage requirement and computation time is lower. To counteract the decay in kernel function, we introduced a depth weighting function for anomalous bodies at the same depth, with information about anomalous body depth obtained from well log and seismic exploration data. For anomalous bodies at different depths, we introduced a spatial gradient weighting function to incorporate additional information obtained in the inversion. We concluded that the spatial gradient weighting function enhanced the spatial resolution of the recovered model. Furthermore, our results showed that including multiple components for inversion increased the resolution of the recovered model. We validated our model by applying our inversion method to survey data from Vinton salt dome, Louisiana, USA. The results showed good agreement with known geologic information; thus confirming the accuracy of this approach.
Daria, Vincent R.; Stricker, Christian; Bekkers, John; Redman, Steve; Bachor, Hans
2010-08-01
We demonstrate a multi-functional system capable of multiple-site two-photon excitation of photo-sensitive compounds as well as transfer of optical mechanical properties on an array of mesoscopic particles. We use holographic projection of a single Ti:Sapphire laser operating in femtosecond pulse mode to show that the projected three-dimensional light patterns have sufficient spatiotemporal photon density for multi-site two-photon excitation of biological fluorescent markers and caged neurotransmitters. Using the same laser operating in continuous-wave mode, we can use the same light patterns for non-invasive transfer of both linear and orbital angular momentum on a variety of mesoscopic particles. The system also incorporates high-speed scanning using acousto-optic modulators to rapidly render 3D images of neuron samples via two-photon microscopy.
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.
Implementation of a 3-D nonlinear MHD [magnetohydrodynamics] calculation on the Intel hypercube
The optimization of numerical schemes and increasing computer capabilities in the last ten years have improved the efficiency of 3-D nonlinear resistive MHD calculations by about two to three orders of magnitude. However, we are still very limited in performing these types of calculations. Hypercubes have a large number of processors with only local memory and bidirectional links among neighbors. The Intel Hypercube at Oak Ridge has 64 processors with 0.5 megabytes of memory per processor. The multiplicity of processors opens new possibilities for the treatment of such computations. The constraint on time and resources favored the approach of using the existing RSF code which solves as an initial value problem the reduced set of MHD equations for a periodic cylindrical geometry. This code includes minimal physics and geometry, but contains the basic three dimensionality and nonlinear structure of the equations. The code solves the reduced set of MHD equations by Fourier expansion in two angular coordinates and finite differences in the radial one. Due to the continuing interest in these calculations and the likelihood that future supercomputers will take greater advantage of parallelism, the present study was initiated by the ORNL Exploratory Studies Committee and funded entirely by Laboratory Discretionary Funds. The objectives of the study were: to ascertain the suitability of MHD calculation for parallel computation, to design and implement a parallel algorithm to perform the computations, and to evaluate the hypercube, and in particular, ORNL's Intel iPSC, for use in MHD computations
Progress in nonlinear nano-optics
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.
Characterization of a parallel-beam CCD optical-CT apparatus for 3D radiation dosimetry
Krstajic, Nikola; Doran, Simon J.
2007-07-01
3D measurement of optical attenuation is of interest in a variety of fields of biomedical importance, including spectrophotometry, optical projection tomography (OPT) and analysis of 3D radiation dosimeters. Accurate, precise and economical 3D measurements of optical density (OD) are a crucial step in enabling 3D radiation dosimeters to enter wider use in clinics. Polymer gels and Fricke gels, as well as dosimeters not based around gels, have been characterized for 3D dosimetry over the last two decades. A separate problem is the verification of the best readout method. A number of different imaging modalities (magnetic resonance imaging (MRI), optical CT, x-ray CT and ultrasound) have been suggested for the readout of information from 3D dosimeters. To date only MRI and laser-based optical CT have been characterized in detail. This paper describes some initial steps we have taken in establishing charge coupled device (CCD)-based optical CT as a viable alternative to MRI for readout of 3D radiation dosimeters. The main advantage of CCD-based optical CT over traditional laser-based optical CT is a speed increase of at least an order of magnitude, while the simplicity of its architecture would lend itself to cheaper implementation than both MRI and laser-based optical CT if the camera itself were inexpensive enough. Specifically, we study the following aspects of optical metrology, using high quality test targets: (i) calibration and quality of absorbance measurements and the camera requirements for 3D dosimetry; (ii) the modulation transfer function (MTF) of individual projections; (iii) signal-to-noise ratio (SNR) in the projection and reconstruction domains; (iv) distortion in the projection domain, depth-of-field (DOF) and telecentricity. The principal results for our current apparatus are as follows: (i) SNR of optical absorbance in projections is better than 120:1 for uniform phantoms in absorbance range 0.3 to 1.6 (and better than 200:1 for absorbances 1.0 to
Binzoni, Tiziano; Torricelli, Alessandro; Giust, Remo; Sanguinetti, Bruno; Bernhard, Paul; Spinelli, Lorenzo
2014-01-01
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 r...
Nanoimprint of a 3D structure on an optical fiber for light wavefront manipulation
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.
Non-linear 3D Born Shear Wave Tomography in Southeastern Asia
Cao, A.; Panning, M.; Kim, A.; Romanowicz, B.
2007-12-01
We have developed a 3D radially anisotropic shear velocity model of the upper mantle in southeastern Asia from the inversion of long period seismic multimode waveforms. Our approach is based on normal mode perturbation theory, specifically, on a recent modification of the Born approximation, which we call "N-Born", and which includes a non-linear term that allows the accurate inclusion of accumulated phase shifts which arise when the wavepath traverses a spatially extended region with a smooth velocity anomaly of constant sign. We apply the N-Born approximation in the forward modeling part and calculate linear 3D Born kernels in the inverse part. Our starting model is a 3D radially anisotropic model which we derived from a large dataset of teleseismic multimode long period waveforms in the period range 60 to 400 s, using a finite-frequency 2D approximation (NACT, Li and Romanowicz, 1995). This model covered a larger region of East Asia (longitude 30 to 150 degrees and latitude -10 to 60 degrees), while our N-Born model is restricted to a smaller subregion (longitude 75 to 150 degrees and latitude 0 to 45 degrees) for computational efficiency. In this subregion, our N-Born isotropic and anisotropic models are both parameterized at relatively short wavelengths corresponding to a spherical spline level 6 (~200km). Our N-Born model can fit waveforms as well as the NACT model, with up to ~ 83% variance reduction. While the models agree in general, the N-Born isotropic model shows a stronger fast velocity anomaly beneath the Tibetan plateau in the depth range of 150 km to 250 km, which disappears at greater depth, consistent with other studies. More importantly, the N-Born anisotropic model can recover well the downwelling structure associated with subducted slabs. Beneath the Tibet plateau, radial anisotropy shows VSH>VSV, which is indicative of horizontal rather than vertical flow and may help distinguish between end member models of the tectonics of Tibet.
Nonlinear Optics of Hexaphenyl Nanofibers
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...
Nonlinear optical properties of bacteriorhodopsin
Hendrickx, Eric; Verbiest, Thierry; Clays, Koen J.; Persoons, Andre P.
1993-04-01
In this paper we show the applicability of Hyper-Rayleigh scattering to obtain hyperpolarizabilities of ionic and biochemical compounds. It was found that dark-adapted bacteriorhodopsin and its isolated chromophore have considerable second order nonlinear optical properties. Information obtained from depolarization studies of the scattered light is discussed.
3D printing of tissue-simulating phantoms as a traceable standard for biomedical optical measurement
Dong, Erbao; Wang, Minjie; Shen, Shuwei; Han, Yilin; Wu, Qiang; Xu, Ronald
2016-01-01
Optical phantoms are commonly used to validate and calibrate biomedical optical devices in order to ensure accurate measurement of optical properties in biological tissue. However, commonly used optical phantoms are based on homogenous materials that reflect neither optical properties nor multi-layer heterogeneities of biological tissue. Using these phantoms for optical calibration may result in significant bias in biological measurement. We propose to characterize and fabricate tissue simulating phantoms that simulate not only the multi-layer heterogeneities but also optical properties of biological tissue. The tissue characterization module detects tissue structural and functional properties in vivo. The phantom printing module generates 3D tissue structures at different scales by layer-by-layer deposition of phantom materials with different optical properties. The ultimate goal is to fabricate multi-layer tissue simulating phantoms as a traceable standard for optimal calibration of biomedical optical spectral devices.
Target Tracking in 3-D Using Estimation Based Nonlinear Control Laws for UAVs
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.
Regimes of nonlinear depletion and regularity in the 3D Navier–Stokes equations
The periodic 3D Navier–Stokes equations are analyzed in terms of dimensionless, scaled, L2m-norms of vorticity Dm (1 ⩽ m < ∞). The first in this hierarchy, D1, is the global enstrophy. Three regimes naturally occur in the D1 − Dm plane. Solutions in the first regime, which lie between two concave curves, are shown to be regular, owing to strong nonlinear depletion. Moreover, numerical experiments have suggested, so far, that all dynamics lie in this heavily depleted regime [1]; new numerical evidence for this is presented. Estimates for the dimension of a global attractor and a corresponding inertial range are given for this regime. However, two more regimes can theoretically exist. In the second, which lies between the upper concave curve and a line, the depletion is insufficient to regularize solutions, so no more than Leray's weak solutions exist. In the third, which lies above this line, solutions are regular, but correspond to extreme initial conditions. The paper ends with a discussion on the possibility of transition between these regimes. (paper)
Nonlinear 3-D simulation of high-intensity focused ultrasound therapy in the kidney
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....
This work proposes a novel approach to segmenting randomly stacked objects in unstructured 3D point clouds, which are acquired by a random-speckle 3D imaging system for the purpose of automated object detection and reconstruction. An innovative algorithm is proposed; it is based on a novel concept of 3D watershed segmentation and the strategies for resolving over-segmentation and under-segmentation problems. Acquired 3D point clouds are first transformed into a corresponding orthogonally projected depth map along the optical imaging axis of the 3D sensor. A 3D watershed algorithm based on the process of distance transformation is then performed to detect the boundary, called the edge dam, between stacked objects and thereby to segment point clouds individually belonging to two stacked objects. Most importantly, an object-matching algorithm is developed to solve the over- and under-segmentation problems that may arise during the watershed segmentation. The feasibility and effectiveness of the method are confirmed experimentally. The results reveal that the proposed method is a fast and effective scheme for the detection and reconstruction of a 3D object in a random stack of such objects. In the experiments, the precision of the segmentation exceeds 95% and the recall exceeds 80%. (paper)
Two-Photon Absorbing Molecules as Potential Materials for 3D Optical Memory
Kazuya Ogawa
2014-01-01
Full Text Available In this review, recent advances in two-photon absorbing photochromic molecules, as potential materials for 3D optical memory, are presented. The investigations introduced in this review indicate that 3D data storage processing at the molecular level is possible. As 3D memory using two-photon absorption allows advantages over existing systems, the use of two-photon absorbing photochromic molecules is preferable. Although there are some photochromic molecules with good properties for memory, in most cases, the two-photon absorption efficiency is not high. Photochromic molecules with high two-photon absorption efficiency are desired. Recently, molecules having much larger two-photon absorption cross sections over 10,000 GM (GM= 10−50 cm4 s molecule−1 photon−1 have been discovered and are expected to open the way to realize two-photon absorption 3D data storage.
Nonlinear fiber optics formerly quantum electronics
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
Nanoimprint of a 3D structure on an optical fiber for light wavefront manipulation
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...
Non-linear 3-D Born shear waveform tomography in Southeast Asia
Panning, Mark P.; Cao, Aimin; Kim, Ahyi; Romanowicz, Barbara A.
2012-07-01
Southeast (SE) Asia is a tectonically complex region surrounded by many active source regions, thus an ideal test bed for developments in seismic tomography. Much recent development in tomography has been based on 3-D sensitivity kernels based on the first-order Born approximation, but there are potential problems with this approach when applied to waveform data. In this study, we develop a radially anisotropic model of SE Asia using long-period multimode waveforms. We use a theoretical 'cascade' approach, starting with a large-scale Eurasian model developed using 2-D Non-linear Asymptotic Coupling Theory (NACT) sensitivity kernels, and then using a modified Born approximation (nBorn), shown to be more accurate at modelling waveforms, to invert a subset of the data for structure in a subregion (longitude 75°-150° and latitude 0°-45°). In this subregion, the model is parametrized at a spherical spline level 6 (˜200 km). The data set is also inverted using NACT and purely linear 3-D Born kernels. All three final models fit the data well, with just under 80 per cent variance reduction as calculated using the corresponding theory, but the nBorn model shows more detailed structure than the NACT model throughout and has much better resolution at depths greater than 250 km. Based on variance analysis, the purely linear Born kernels do not provide as good a fit to the data due to deviations from linearity for the waveform data set used in this modelling. The nBorn isotropic model shows a stronger fast velocity anomaly beneath the Tibetan Plateau in the depth range of 150-250 km, which disappears at greater depth, consistent with other studies. It also indicates moderate thinning of the high-velocity plate in the middle of Tibet, consistent with a model where Tibet is underplated by Indian lithosphere from the south and Eurasian lithosphere from the north, in contrast to a model with continuous underplating by Indian lithosphere across the entire plateau. The n
Construction modification of data-projector for optical 3D measurement
Pochmon, Michal; Pravdová, L.; Rössler, T.
Ostrava: VŠB - TU, 2008 - (Fuxa, J.; Macura, P.; Halama, R.), s. 199-202 ISBN 978-80-248-1774-3. [Experimental Stress Analysis (EAN) 2008. International scientific conference /46./. Horní Bečva (CZ), 02.06.2008-05.06.2008] R&D Projects: GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : data -projector * optical 3D measurement Subject RIV: BH - Optics, Masers, Lasers
High resolution 3D dosimetry for microbeam radiation therapy using optical CT
Optical Computed Tomography (CT) is a promising technique for dosimetry of Microbeam Radiation Therapy (MRT), providing high resolution 3D dose maps. Here different MRT irradiation geometries are visualised showing the potential of Optical CT as a tool for future MRT trials. The Peak-to-Valley dose ratio (PVDR) is calculated to be 7 at a depth of 3mm in the radiochromic dosimeter PRESAGE®. This is significantly lower than predicted values and possible reasons for this are discussed
A Closed Form Solution to Segment 3D Motion Using Straight-line Optical Flow
ZHANG Jing; SHI Fan-huai; MA Wen-juan; LIU Yun-cai
2008-01-01
A closed form solution to the problem of segmenting multiple 3D motion models was proposed fromstraight-line optical flow. It introduced the multibody line optical flow constraint (MLOFC), a polynomial equation relating motion models and line parameters. The motion models can be obtained analytically as the derivative of the MLOFC at the corresponding line measurement, without knowing the motion model associated with that line. Experiments on real and synthetic sequences were also presented.
3D micro-optical elements for generation of tightly focused vortex beams
Balčytis Armandas; Hakobyan Davit; Gabalis Martynas; Žukauskas Albertas; Urbonas Darius; Malinauskas Mangirdas; Petruškevičius Raimondas; Brasselet Etienne; Juodkazis Saulius
2015-01-01
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 ...
Fiber Optic 3-D Space Piezoelectric Accelerometer and its Antinoise Technology
无
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.
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).
Nonlinear Optical Studies of Bacteriorhodopsin
Rao, D. V. G. L. N.; Aranda, F. J.; Chen, Z.; Akkara, J. A.; Kaplan, D. L.; Nakashima, M.
We report interesting results on nonlinear optics at low powers in bacteriorhodopsin films with applications in all-optical switching and modulation. Chemically stabilized films of bacteriorhodopsin in a polymer matrix for which the lifetime of the excited M state is 3 to 4 orders of magnitude longer than that of water solutions of wild-type bR were used in these experiments. Due to the sensitivity of the films, very small powers of order microwatts are required for optical phase conjugation. The influence of the fast photochemical M to B transition induced by blue light on the saturation intensity, phase conjugate intensity and switching time was established. We also report our measurements of the intensity dependence of the self-focusing and self-defocusing properties of wild-type bR in water solution using the Z-scan technique with low power cw lasers at two wavelengths on either side of the absorption band. Our measurements indicate that the sign of the nonlinearity depends on the wavelength and the magnitude depends on the fluence of the incident laser beam. The observed self-focusing and defocusing is not due to the intrinsic electronic nonlinearity. The observations can be explained in terms of the Kramers-Kronig dispersion relation that relates the real and imaginary parts of the complex index of refraction.
Performance of an improved first generation optical CT scanner for 3D dosimetry
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. (note)
3D optical vortices generated by micro-optical elements and its novel applications
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
Wang, Minjie; Shen, Shuwei; Yang, Jie; Dong, Erbao; Xu, Ronald
2014-03-01
The performance of biomedical optical imaging devices heavily relies on appropriate calibration. However, many of existing calibration phantoms for biomedical optical devices are based on homogenous materials without considering the multi-layer heterogeneous structures observed in biological tissue. Using such a phantom for optical calibration may result in measurement bias. To overcome this problem, we propose a 3D printing method for freeform fabrication of tissue simulating phantoms with multilayer heterogeneous structure. The phantom simulates not only the morphologic characteristics of biological tissue but also absorption and scattering properties. The printing system is based on a 3D motion platform with coordinated control of the DC motors. A special jet nozzle is designed to mix base, scattering, and absorption materials at different ratios. 3D tissue structures are fabricated through layer-by-layer printing with selective deposition of phantom materials of different ingredients. Different mixed ratios of base, scattering and absorption materials have been tested in order to optimize the printing outcome. A spectrometer and a tissue spectrophotometer are used for characterizing phantom absorption and scattering properties. The goal of this project is to fabricate skin tissue simulating phantoms as a traceable standard for the calibration of biomedical optical spectral devices.
Graphene - a rather ordinary nonlinear optical material
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.
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.
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.
Nonlinear Image Formation by Optical Superlattices
Yang, Bo; Lu, Rong-Er; Yue, Yang-Yang; Zhang, Chao; Qin, Yi-Qiang; Zhu, Yong-Yuan
2015-01-01
The angular spectrum theory is applied to the nonlinear harmonic generation process in optical superlattices. Several explicit and analytical structure functions are deduced to design optical superlattices for various purposes. Employing this method, nonlinear image formation is achieved during the second-harmonic generation process in a properly designed optical superlattice. This method is universal for both nonlinear beam shaping and nonlinear arbitrary image formation. The theory has been experimentally validated in two-dimensional optical superlattice of LiTaO3 crystals and the results agree well with the theoretical prediction. This work not only extends the application of optical superlattices, but also opens a new area for imaging technologies.
Uhrig, Matthias P.; Kim, Jin-Yeon; Jacobs, Laurence J.
2016-02-01
This research presents a 3D numerical finite element (FE) model which, previously developed, precisely simulates non-contact, air-coupled measurements of nonlinear Rayleigh wave propagation. The commercial FE-solver ABAQUS is used to perform the simulations. First, frequency dependent pressure wave attenuation is investigated numerically to reconstruct the sound pressure distribution along the active surface of the non-contact receiver. Second, constitutive law and excitation source properties are optimized to match nonlinear ultrasonic experimental data. Finally, the FE-model data are fit with analytical solutions showing a good agreement and thus, indicating the significance of the study performed.
Measurement of abrasion of artificial cotyles using 3D optical scanning topography
Mandát, Dušan; Nožka, Libor; Hrabovský, Miroslav; Bartoněk, L.
Zagreb: Croatian Society of Mechanics, 2004 - (Jecic, S.; Semenski, D.), s. 92-93 ISBN 953-96243-6-3. [DANUBIA-ADRIA Symposium on Experimental Methods in Solid Mechanics /21./. Brijuni - Pula (HR), 29.09.2004-02.10.2004] R&D Projects: GA MŠk LN00A015 Grant ostatní: GA-(CZ) FRVŠ48/2004 Keywords : profilometry * 3D topography * cotyle * VRML language Subject RIV: BH - Optics, Masers, Lasers
3D printed sensing patches with embedded polymer optical fibre Bragg gratings
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.
Lensfree Optical Tomography for High-Throughput 3D Imaging on a Chip
ISIKMAN, SERHAN OMER
2012-01-01
Light microscopes provide us with the key to observe objects that are orders of magnitude smaller than what the unaided eye can see. Therefore, microscopy has been the cornerstone of science and medicine for centuries. Recently, optical microscopy has seen a growing interest in developing three-dimensional (3D) imaging techniques that enable sectional imaging of biological specimen. These imaging techniques, however, are generally quite complex, bulky and expensive in addition to having a lim...
Performance of a commercial optical CT scanner and polymer gel dosimeters for 3-D dose verification
Performance analysis of a commercial three-dimensional (3-D) dose mapping system based on optical CT scanning of polymer gels is presented. The system consists of BANGreg3 polymer gels (MGS Research, Inc., Madison, CT), OCTOPUSTM laser CT scanner (MGS Research, Inc., Madison, CT), and an in-house developed software for optical CT image reconstruction and 3-D dose distribution comparison between the gel, film measurements and the radiation therapy treatment plans. Various sources of image noise (digitization, electronic, optical, and mechanical) generated by the scanner as well as optical uniformity of the polymer gel are analyzed. The performance of the scanner is further evaluated in terms of the reproducibility of the data acquisition process, the uncertainties at different levels of reconstructed optical density per unit length and the effects of scanning parameters. It is demonstrated that for BANGregistered3 gel phantoms held in cylindrical plastic containers, the relative dose distribution can be reproduced by the scanner with an overall uncertainty of about 3% within approximately 75% of the radius of the container. In regions located closer to the container wall, however, the scanner generates erroneous optical density values that arise from the reflection and refraction of the laser rays at the interface between the gel and the container. The analysis of the accuracy of the polymer gel dosimeter is exemplified by the comparison of the gel/OCT-derived dose distributions with those from film measurements and a commercial treatment planning system (Cadplan, Varian Corporation, Palo Alto, CA) for a 6 cmx6 cm single field of 6 MV x rays and a 3-D conformal radiotherapy (3DCRT) plan. The gel measurements agree with the treatment plans and the film measurements within the '3%-or-2 mm' criterion throughout the usable, artifact-free central region of the gel volume. Discrepancies among the three data sets are analyzed
Koppenhoefer, Kyle C.; Gullerud, Arne S.; Ruggieri, Claudio; Dodds, Robert H., Jr.; Healy, Brian E.
1998-01-01
This report describes theoretical background material and commands necessary to use the WARP3D finite element code. WARP3D is under continuing development as a research code for the solution of very large-scale, 3-D solid models subjected to static and dynamic loads. Specific features in the code oriented toward the investigation of ductile fracture in metals include a robust finite strain formulation, a general J-integral computation facility (with inertia, face loading), an element extinction facility to model crack growth, nonlinear material models including viscoplastic effects, and the Gurson-Tver-gaard dilatant plasticity model for void growth. The nonlinear, dynamic equilibrium equations are solved using an incremental-iterative, implicit formulation with full Newton iterations to eliminate residual nodal forces. The history integration of the nonlinear equations of motion is accomplished with Newmarks Beta method. A central feature of WARP3D involves the use of a linear-preconditioned conjugate gradient (LPCG) solver implemented in an element-by-element format to replace a conventional direct linear equation solver. This software architecture dramatically reduces both the memory requirements and CPU time for very large, nonlinear solid models since formation of the assembled (dynamic) stiffness matrix is avoided. Analyses thus exhibit the numerical stability for large time (load) steps provided by the implicit formulation coupled with the low memory requirements characteristic of an explicit code. In addition to the much lower memory requirements of the LPCG solver, the CPU time required for solution of the linear equations during each Newton iteration is generally one-half or less of the CPU time required for a traditional direct solver. All other computational aspects of the code (element stiffnesses, element strains, stress updating, element internal forces) are implemented in the element-by- element, blocked architecture. This greatly improves
Sayed, Ahmed; Layne, Ginger; Abraham, Jame; Mukdadi, Osama
2013-01-01
The main objective of this article is to introduce a new nonlinear elastography based classification method for human breast masses. Multi-compression elastography imaging is elucidated in this study to differentiate malignant from benign lesions, based on their nonlinear mechanical behavior under compression. Three classification parameters were used and compared in this work: a new nonlinear parameter based on a power-law behavior of the strain difference between breast masses and healthy t...
Nanoplasmonic solution for nonlinear optics
Bache, Morten; Lavrinenko, Andrei; Lysenko, Oleg;
2014-01-01
spectrum for the silicon dioxide cladding. The blue, cyan and magenta curves correspond to the transmission spectra for the gold waveguides with the width of 10 μm and length of 2, 3, and 4 mm.The polarization of laser beam was tuned to match the transverse magnetic mode of surface plasmonpolaritons in the...... is being under investigation in recent years [3].The purpose of our research is to study nonlinear optical properties of gold waveguides embedded intodielectric medium (silicon dioxide) using picosecond laser spectroscopy. The work includes modeling ofoptical properties of gold waveguides......, fabrication of prototype samples, and optical characterization ofsamples using a picosecond laser source.The prototype samples of gold waveguides embedded into silicon dioxide were fabricated at DTUDanchip. A silicon wafer with pre-made 6.5 μm layer of silicon dioxide was used as a substrate and...
Minimizing camera-eye optical aberrations during the 3D reconstruction of retinal structures
Aldana-Iuit, Javier; Martinez-Perez, M. Elena; Espinosa-Romero, Arturo; Diaz-Uribe, Rufino
2010-05-01
3D reconstruction of blood vessels is a powerful visualization tool for physicians, since it allows them to refer to qualitative representation of their subject of study. In this paper we propose a 3D reconstruction method of retinal vessels from fundus images. The reconstruction method propose herein uses images of the same retinal structure in epipolar geometry. Images are preprocessed by RISA system for segmenting blood vessels and obtaining feature points for correspondences. The correspondence points process is solved using correlation. The LMedS analysis and Graph Transformation Matching algorithm are used for outliers suppression. Camera projection matrices are computed with the normalized eight point algorithm. Finally, we retrieve 3D position of the retinal tree points by linear triangulation. In order to increase the power of visualization, 3D tree skeletons are represented by surfaces via generalized cylinders whose radius correspond to morphological measurements obtained by RISA. In this paper the complete calibration process including the fundus camera and the optical properties of the eye, the so called camera-eye system is proposed. On one hand, the internal parameters of the fundus camera are obtained by classical algorithms using a reference pattern. On the other hand, we minimize the undesirable efects of the aberrations induced by the eyeball optical system assuming that contact enlarging lens corrects astigmatism, spherical and coma aberrations are reduced changing the aperture size and eye refractive errors are suppressed adjusting camera focus during image acquisition. Evaluation of two self-calibration proposals and results of 3D blood vessel surface reconstruction are presented.
The quantum theory of nonlinear optics
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...
CMOS array of photodiodes with electronic processing for 3D optical reconstruction
Hornero, Gemma; Montane, Enric; Chapinal, Genis; Moreno, Mauricio; Herms, Atila
2001-04-01
It is well known that laser time-of-flight (TOF) and optical triangulation are the most useful optical techniques for distance measurements. The first one is more suitable for large distances, since for short range of distances high modulation frequencies of laser diodes (©200-500MHz) are needed. For these ranges, optical triangulation is simpler, as it is only necessary to read the projection of the laser point over a linear optical sensor without any laser modulation. Laser triangulation is based on the rotation of the object. This motion shifts the projected point over the linear sensor, resulting on 3D information, by means of the whole readout of the linear sensor in each angle position. On the other hand, a hybrid method of triangulation and TOF can be implemented. In this case, a synchronized scanning of a laser beam over the object results in different arrival times of light to each pixel. The 3D information is carried by these delays. Only a single readout of the linear sensor is needed. In this work we present the design of two different linear arrays of photodiodes in CMOS technology, the first one based on the Optical triangulation measurement and the second one based in this hybrid method (TFO). In contrast to PSD (Position Sensitive Device) and CCDs, CMOS technology can include, on the same chip, photodiodes, control and processing electronics, that in the other cases should be implemented with external microcontrollers.
Nonlinear optical response in higher fullerenes
Harigaya, K.
1997-01-01
Nonlinear optical properties of extracted higher fullerenes - C70, C76, C78, and C84 - are theoretically investigated. Magnitudes of off-resonant third-harmonic-generation are calculated by the intermediate exciton theory. We find that optical nonlinearities of higher fullerenes are a few times larger than those of C60. The magnitudes of nonlinearity tend to increase as the optical gap decreases in higher fullerenes.
Block matching 3D random noise filtering for absorption optical projection tomography
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
Stereoscopic particle tracking for 3D touch, vision and closed-loop control in optical tweezers
Force measurement in an interactive 3D micromanipulation system can allow the user to make delicate adjustments, and to explore surfaces with touch as well as vision. We present a system to achieve this on the micron scale using stereoscopic particle tracking combined with holographic optical tweezers, which can track particles with nanometre accuracy. 2D tracking of particles in each of the stereo images gives 3D positions for each particle. This takes less than 200 µs per image pair, using a 1D 'symmetry transform' applied to each row and column of a 2D image, which can maintain tracking of particles throughout the 10 µm axial range. The only parameters required are the geometry of the imaging system, and therefore there is no need to recalibrate for different particle sizes or refractive indices. Consequently, we can calculate the force exerted by the optical trap in real time at 1 kilohertz, allowing us to implement a force-feedback interface (with a loop rate of 400 Hz). In combination with our OpenGL hologram calculation engine, the system has a closed-loop bandwidth of 20 Hz. This allows us to stabilize trapped particles axially through active feedback, cancelling out some Brownian motion. For the weak traps we use here (spring constant k≈2 pN µm−1), this results in a threefold increase in axial stiffness. We demonstrate the 3D interface by probing an oil droplet, mapping out its surface in the y–z plane
Fast error simulation of optical 3D measurements at translucent objects
Lutzke, P.; Kühmstedt, P.; Notni, G.
2012-09-01
The scan results of optical 3D measurements at translucent objects deviate from the real objects surface. This error is caused by the fact that light is scattered in the objects volume and is not exclusively reflected at its surface. A few approaches were made to separate the surface reflected light from the volume scattered. For smooth objects the surface reflected light is dominantly concentrated in specular direction and could only be observed from a point in this direction. Thus the separation either leads to measurement results only creating data for near specular directions or provides data from not well separated areas. To ensure the flexibility and precision of optical 3D measurement systems for translucent materials it is necessary to enhance the understanding of the error forming process. For this purpose a technique for simulating the 3D measurement at translucent objects is presented. A simple error model is shortly outlined and extended to an efficient simulation environment based upon ordinary raytracing methods. In comparison the results of a Monte-Carlo simulation are presented. Only a few material and object parameters are needed for the raytracing simulation approach. The attempt of in-system collection of these material and object specific parameters is illustrated. The main concept of developing an error-compensation method based on the simulation environment and the collected parameters is described. The complete procedure is using both, the surface reflected and the volume scattered light for further processing.
3D optical printing of piezoelectric nanoparticle-polymer composite materials.
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. PMID:25046646
Nonlinear optics: Fundamentals, materials and devices
The field of nonlinear optics developed gradually with the invention of lasers. After discovery of second-harmonic generation in quartz, many other interesting nonlinear optical processes were rapidly discovered. Theoretical programmes for understanding nonlinear optical phenomena were stimulated simultaneously in accordance to develop structure-property relationships. In the beginning research advances were made on inorganic ferroelectric material followed by semiconductors. In the 1970's the importance of organic materials was realised because of their nonlinear optical responses, fast optical response, high laser damage thresholds, architectural flexibility, and ease of fabrication. At present materials can be classified into three categories: inorganic ferroelectrics, semiconductors, and organic materials. Advances have also been made in quantum chemistry approaches to investigate nonlinear optical susceptibilities and in the development of novel nonlinear optical devices. Generally, inorganic and organic nonlinear optical materials and their related optical processes are reported in separate meetings. This book collects papers covering recent developments and areas of present research in the field of nonlinear optical materials
Progress in the Peeling-Ballooning Model of ELMs: Numerical Studies of 3D Nonlinear ELM Dynamics
Snyder, P B; Wilson, H R; Xu, X Q
2004-12-13
Nonlinear simulations with the 3D electromagnetic two-fluid BOUT code are employed to study the dynamics of edge localized modes (ELMs) driven by intermediate wavelength peeling-ballooning modes. It is found that the early behavior of the modes is similar to expectations from linear, ideal peeling-ballooning mode theory, with the modes growing linearly at a fraction of the Alfven frequency. In the non-linear phase, the modes grow explosively, forming a number of extended filaments which propagate rapidly from the outer closed flux region into the open flux region toward the outer wall. Similarities to non-linear linear ballooning theory, as well as additional complexities are observed. Comparison to observations reveals a number of similarities. Implications of the simulations and proposals for the dynamics of the full ELM crash are discussed.
PROGRESS IN THE PEELING-BALLOONING MODEL OF ELMS: NUMERICAL STUDIES OF 3D NONLINEAR ELM DYNAMICS
SNYDER,P.B; WILSON,H.R; XU,X.Q
2004-11-01
Nonlinear simulations with the 3D electromagnetic two-fluid BOUT code are employed to study the dynamics of edge localized modes (ELMs) driven by intermediate wavelength peeling-ballooning modes. It is found that the early behavior of the modes is similar to expectations from linear, ideal peeling-ballooning mode theory, with the modes growing linearly at a fraction of the Alfven frequency. In the nonlinear phase, the modes grow explosively, forming a number of extended filaments which propagate rapidly from the outer closed flux region into the open flux region toward the outboard wall. Similarities to non-linear ballooning theory, as well as additional complexities are observed. Comparison to observations reveals a number of similarities. Implications of the simulations and proposals for the dynamics of the full ELM crash are discussed.
PROGRESS IN THE PEELING-BALLOONING MODEL OF ELMS: NUMERICAL STUDIES OF 3D NONLINEAR ELM DYNAMICS
Nonlinear simulations with the 3D electromagnetic two-fluid BOUT code are employed to study the dynamics of edge localized modes (ELMs) driven by intermediate wavelength peeling-ballooning modes. It is found that the early behavior of the modes is similar to expectations from linear, ideal peeling-ballooning mode theory, with the modes growing linearly at a fraction of the Alfven frequency. In the nonlinear phase, the modes grow explosively, forming a number of extended filaments which propagate rapidly from the outer closed flux region into the open flux region toward the outboard wall. Similarities to non-linear ballooning theory, as well as additional complexities are observed. Comparison to observations reveals a number of similarities. Implications of the simulations and proposals for the dynamics of the full ELM crash are discussed
Architectures and algorithms for all-optical 3D signal processing
Giglmayr, Josef
1999-07-01
All-optical signal processing by >= 2D lightwave circuits (LCs) is (i) aimed to allow the (later) inclusion of the frequency domain and is (ii) subject to photonic integration and thus the architectural and algorithmic framework has to be prepared carefully. Much work has been done in >= 2D algebraic system theory/modern control theory which has been applied in the electronic field of signal and image processing. For the application to modeling, analysis and design of the proposed 3D lightwave circuits (LCs) some elements are needed to describe and evalute the system efficiency as the number of system states of 3D LCs increases dramatically with regard to the number of i/o. Several problems, arising throughput such an attempt, are made transparent and solutions are proposed.
Nonlinear 3-D beam/connector finite element with warping for a glulam dome
Kavi, Sandeep A.
1993-01-01
The main objectives of the present study are to incorporate Saint-Venant's torsion solution in the analysis of a glulam dome with ABAQUS to include warping of rectangular beams, and to model the nonlinear beam/decking connectors (nails) of the dome in order to develop an effective finite element model of the glulam dome for investigating its ultimate load capacity. The shear modulus is modified to include warping of the beams. The nonlinear connector is defined through a user-c...
On Nonlinear Stability Theorems of 3D Quasi-geostrophic Flow
无
2006-01-01
Nonlinear stability criteria for quasi-geostrophic zonally symmetric flow are improved by establishing an invariant of zonal momentum. When applied to the Eady model in a periodic channel with finite zonal length, the improved nonlinear stability criterion is identical to the linear normal-mode stability criterion provided the channel meridional width is no greater than 0.8605... times its channel length (which is the geophysically relevant case).
Intrathoracic tumour motion estimation from CT imaging using the 3D optical flow method
Guerrero, Thomas [Division of Radiation Oncology, University of Texas M D Anderson Cancer Center, Houston, TX 77030 (United States); Zhang, Geoffrey [Division of Radiation Oncology, University of Texas M D Anderson Cancer Center, Houston, TX 77030 (United States); Huang Tzungchi [Division of Radiation Oncology, University of Texas M D Anderson Cancer Center, Houston, TX 77030 (United States); Lin Kaping [Department of Electrical Engineering, Chung-Yuan University, Taipei, Taiwan (China)
2004-09-07
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.
Intrathoracic tumour motion estimation from CT imaging using the 3D optical flow method
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.
Intrathoracic tumour motion estimation from CT imaging using the 3D optical flow method
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
Three-Axis Distributed Fiber Optic Strain Measurement in 3D Woven Composite Structures
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
Holey optical fibres for high nonlinearity devices
Belardi, Walter
2003-01-01
This thesis describes the development of a novel type of optical fibre, namely holey optical fibre (HF), for its specific incorporation in optical devices based on fibre nonlinearity. The development of the fabrication technique to produce such a fibre is discussed, and the fibres produced are characterized and used in device applications, proving the advantages of HF technology in the implementation of highly nonlinear optical devices, as well as showing its limitations. The initial fabricat...
Nonlinear analysis of chaotic flow in a 3D closed-loop pulsating heat pipe
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...
Huimin Yu
2012-01-01
The asymptotic behavior (as well as the global existence) of classical solutions to the 3D compressible Euler equations are considered. For polytropic perfect gas $(P(\\rho )={P}_{0}{\\rho }^{\\gamma })$ , time asymptotically, it has been proved by Pan and Zhao (2009) that linear damping and slip boundary effect make the density satisfying the porous medium equation and the momentum obeying the classical Darcy's law. In this paper, we use a more general method and extend this resu...
Optical tomographic in-air scanner for external radiation beam 3D gel dosimetry
Full text: Optical CT scanners are used to measure 3D radiation dose distributions in radiosensitive gels. For radiotherapy dose verification, 3D dose measurements are useful for verification of complex linear accelerator treatment planning and delivery techniques. Presently optical CTs require the use of a liquid bath to match the refractive index of the gel to minimise refraction of the light rays leading to distortion and artifacts. This work aims to develop a technique for scanning gel samples in free-air, without the requirement for a matching liquid bath. The scanner uses a He-Ne laser beam, fanned across the acrylic cylindrical gel container by a rotating mirror. The gel container was designed to produce parallel light ray paths through the gel. A pin phantom was used to quantify geometrical distortion of the reconstructed image, while uniform field exposures were used to consider noise, uniformity and artifacts. Small diameter wires provided an indication of the spatial resolution of the scanner. Pin phantom scans show geometrical distortion comparable to scanners using matching fluid baths. Noise, uniformity and artifacts were not found to be major limitations for this scanner approach. Spatial resolution was limited by laser beam spot size, typically 0.4 mm full width half maximum. A free-air optical CT scanner has been developed with the advantage of scanning without a matching fluid bath. Test results show it has potential to provide suitable quality 3D dosimetry measurements for external beam dose verification, while offering significant advantages in convenience and efficiency for routine use.
Measuring nonlinear stresses generated by defects in 3D colloidal crystals
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 ...
Time-reversal symmetry in nonlinear optics
Trzeciecki, M.; Hübner, W.
2000-01-01
The applicability of time-reversal symmetry to nonlinear optics is discussed, both from macroscopic (Maxwell equations) and microscopic (quantum theoretical) point of view. We find that only spatial operations can be applied for the symmetry classification of nonlinear optical processes in magnetic, in particular antiferromagnetic, materials. An example is given where both operations (time reversal and a spatial operation) can yield different results.
Ultra-compact on-chip LED collimation optics by 3D femtosecond direct laser writing.
Thiele, Simon; Gissibl, Timo; Giessen, Harald; Herkommer, Alois M
2016-07-01
By using two-photon lithographic 3D printing, we demonstrate additive manufacturing of a dielectric concentrator directly on a LED chip. With a size of below 200 μm in diameter and length, light output is increased by a factor of 6.2 in collimation direction, while the emission half-angle is reduced by 50%. We measure excellent form fidelity and irradiance patterns close to simulation. Additionally, a more complex shape design is presented, which exhibits a nonconventional triangular illumination pattern. The introduced method features exceptional design freedoms which can be used to tailor high-quality miniature illumination optics for specific lighting tasks, for example, endoscopy. PMID:27367093
Optical scanning of dusty 3D-structures formed in a glow discharge
Karasev, V. Yu.; Dzlieva, E. S.; Ivanov, A. Yu.; Éĭkhval'D, A. I.; Golubev, M. V.
2009-06-01
3D-quasi-crystals formed in strata of a glow discharge are scanned in the optical range with the help of a moving laser knife and high-speed videorecording. The spatial positions of dusty grains are determined. The ordering of structures and the type of arrangement of particles are determined from a comparison of pair correlation functions constructed for the structures under study with correlation functions corresponding to ideal crystalline structures. Several types of unit cells are found through the visual collation of separate parts of structures. As compared to data from the literature on experiments in a high-frequency discharge, the structures under study have a clearly pronounced anisotropy.
New light sources and sensors for active optical 3D inspection
Osten, Wolfgang; Jueptner, Werner P. O.
1999-11-01
The implementation of active processing strategies in optical 3D-inspection needs the availability of flexible hardware solutions. The system components illumination and sensor/detector are actively involved in the processing chain by a feedback loop that is controlled by the evaluation process. Therefore this article deals with new light sources and sensor which appeared recently on the market and can be applied successfully for the implementation of active processing principles. Some applications where such new components are used to implement an active measurement strategy are presented.
Quantification of smoothing requirement for 3D optic flow calculation of volumetric images
Bab-Hadiashar, Alireza; Tennakoon, Ruwan B.; de Bruijne, Marleen
2013-01-01
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...... 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...
Shot noise limit of the optical 3D measurement methods for smooth surfaces
The measurement uncertainty of optical 3D measurement methods for smooth surfaces caused by shot noise is investigated. The shot noise is a fundamental property of the quantum nature of light. If all noise sources are eliminated, the shot noise represents the ultimate limit of the measurement uncertainty. The measurement uncertainty is calculated for several simple model methods. The analysis shows that the measurement uncertainty depends on the wavelength of used light, the number of photons used for the measurement, and on a factor that is connected with the geometric arrangement of the measurement setup. (paper)
3D optical sectioning with a new hyperspectral confocal fluorescence imaging system.
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.
Diffractive 3D XUV optics at Helmholtz-Zentrum Berlin, recent developments
Brzhezinskaya, Maria; Firsov, Alexander; Erko, Alexei
2014-09-01
The 2-Dimensional and 3-Dimensional variable line spacing (VLS) gratings based on total external reflection give the unique possibility for spectroscopy and focusing in application to 4th and 5th generation synchrotron sources. We focus on the elaboration of novel approaches for design and fabrication of 3D VLS working in the entire energy range, from THz to hard X-rays. These optical elements have unique combination of properties and can operate at all XUV sources including Free Electron Lasers (FELs), Energy Recovery Linacs (ERLs) and High Harmonic Generators (HHGs). Such 3D DOEs are able to cover the energy range of up to 20 keV with energy resolution λ/Δλ ≥ 1000 for soft x-ray and λ/Δλ ≥ 10000 for hard x-ray. We fabricate 3D VLS for time-resolved spectroscopy (energy range 100 - 2000 eV, 7500-9500 eV), FELs and ERLs (energy range up to 3 keV), and HHGs (energy range 10 - 200 eV).
Polymer optical fibers integrated directly into 3D orthogonal woven composites for sensing
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. (paper)
Optical properties of 3d transition metal ion-doped sodium borosilicate glass
Graphical abstract: Photographs of undoped (SiO2)50 (Na2O)25 (B2O3)25 (SiNaB) glass and transition metal ion-doped (TM)0.5 (SiO2)49.5 (Na2O)25 (B2O3)25 glass samples. - Highlights: • 3d transition metal ion (from Ti to Zn) doped SiO2-Na2O-B2O3 glasses. • Optical properties of doped glasses investigated. • V(IV,V); Cr(III, VI); Mn(II,III); Fe(II,III); Co(II); Ni(II); Cu(II) by XANES, DRS. • Strong visible absorption but only vanadium ion gives strong emission in glass. - Abstract: SiO2-Na2O-B2O3 glasses doped with 3d-transition metal species from Ti to Zn were prepared by the melting-quenching technique and their optical properties were investigated. The X-ray absorption near edge spectra of V, Cr, and Mn-doped glasses indicate that the oxidation states of V(IV, V), Cr(III, VI) and Mn(II, III) exist in the studied glasses. The oxidation states revealed from the diffuse reflectance spectra of the glasses are V(IV, V), Cr(III, VI), Mn(III), Fe(II, III), Co(II), Ni(II), and Cu(II). Most of the 3d transition element ions exhibit strong absorption in the visible spectral region in the glass. Under ultraviolet excitation, the undoped sodium borosilicate glass produces weak and broad emission, while doping of vanadium introduces strong and broad emission due to the V(V) charge transfer transition. Only weak emission is observed from Ti(IV), Mn(II), Fe(III) and Cu(II), partly resulting from the strong electron–phonon coupling of the 3d-electrons and the relatively high phonon energy of the studied glass host, with the former leading to dominant nonradiative relaxation based on multiphonon processes for most of the 3d excited states
Optical properties of 3d transition metal ion-doped sodium borosilicate glass
Wen, Hongli [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, Guangdong (China); Tanner, Peter A., E-mail: peter.a.tanner@gmail.com [Department of Science and Environmental Studies, The Hong Kong Institute of Education, 10 Lo Ping Road, Tai Po, N.T., Hong Kong Special Administrative Region (Hong Kong)
2015-03-15
Graphical abstract: Photographs of undoped (SiO{sub 2}){sub 50} (Na{sub 2}O){sub 25} (B{sub 2}O{sub 3}){sub 25} (SiNaB) glass and transition metal ion-doped (TM){sub 0.5} (SiO{sub 2}){sub 49.5} (Na{sub 2}O){sub 25} (B{sub 2}O{sub 3}){sub 25} glass samples. - Highlights: • 3d transition metal ion (from Ti to Zn) doped SiO{sub 2}-Na{sub 2}O-B{sub 2}O{sub 3} glasses. • Optical properties of doped glasses investigated. • V(IV,V); Cr(III, VI); Mn(II,III); Fe(II,III); Co(II); Ni(II); Cu(II) by XANES, DRS. • Strong visible absorption but only vanadium ion gives strong emission in glass. - Abstract: SiO{sub 2}-Na{sub 2}O-B{sub 2}O{sub 3} glasses doped with 3d-transition metal species from Ti to Zn were prepared by the melting-quenching technique and their optical properties were investigated. The X-ray absorption near edge spectra of V, Cr, and Mn-doped glasses indicate that the oxidation states of V(IV, V), Cr(III, VI) and Mn(II, III) exist in the studied glasses. The oxidation states revealed from the diffuse reflectance spectra of the glasses are V(IV, V), Cr(III, VI), Mn(III), Fe(II, III), Co(II), Ni(II), and Cu(II). Most of the 3d transition element ions exhibit strong absorption in the visible spectral region in the glass. Under ultraviolet excitation, the undoped sodium borosilicate glass produces weak and broad emission, while doping of vanadium introduces strong and broad emission due to the V(V) charge transfer transition. Only weak emission is observed from Ti(IV), Mn(II), Fe(III) and Cu(II), partly resulting from the strong electron–phonon coupling of the 3d-electrons and the relatively high phonon energy of the studied glass host, with the former leading to dominant nonradiative relaxation based on multiphonon processes for most of the 3d excited states.
A continuation method for computing non-linear 3-D free surface flows
Petersson, N.A.
1993-01-01
The subject of this paper is a pseudo-arclength continuation method for computing non-linear three-dimensional steady potential flow around a submerged body moving in a infinitely deep liquid at constant speed and distance below the free surface.
Nonlinear 3D calculations of turbine blade impact on turbine cover
This paper present the approach used at the VUJE institute for the evaluation of a ruptured blade impact on the current protection cover of a SKODA 220 MW turbine. Firstly, it briefly describes experiments (Hopkinson-Davies split bar facility, Taylor tests) and numerical simulations used to obtain realistic material parameters needed for the Cowper- Symonds material model that is implemented in the code LS-DYNA3D. Then, numerical simulations, by using the code, of the ruptured blade impact on various protection barriers are presented. These simulations make it possible to find an optimal solution for a new turbine protection cover. (author)
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.
Fabrication and optical properties of 3D composite photonic crystals of core-shell structures
Liu Yanping [Department of Physics, Lanzhou University, Lanzhou 730000 (China); Yan Zhijun [Department of Physics, Lanzhou University, Lanzhou 730000 (China); Lan Wei [Department of Physics, Lanzhou University, Lanzhou 730000 (China); Huang Chunming [Department of Physics, Lanzhou University, Lanzhou 730000 (China); Wang Yinyue [Department of Physics, Lanzhou University, Lanzhou 730000 (China)]. E-mail: wangyy@lzu.edu.cn
2007-08-31
Three-dimensional (3D) composite colloidal photonic crystals with SiO{sub 2} core and ZnO shell were fabricated on borosilicate glass (BSG) substrate by a two-stage deposition method. Scanning electron microscopy (SEM) measurements show that both the pre-deposited SiO{sub 2} and SiO{sub 2}/ZnO core-shell structures are oriented with their (1 1 1) axes parallel to the substrates. Optical measurement reveals that the periodic arrays exhibit a photonic band gap in the (1 1 1) direction. The optical properties of SiO{sub 2}/ZnO core-shell structures strongly depend on the size dispersions of colloidal spheres and the intrinsic defects in the sample.
Dual wavelength optical CT scanning of anthropomorphic shaped 3D dosimeters
To create an optical density map of 3D dosimeter phantoms, the ratio of the transmission profile (either a line or planar) acquired after irradiation of the dosimeter and a pre-irradiation reference scan of the same dosimeter phantom is taken. Any uncertainty in repositioning of the phantom may result in an uncertainty in the optical density map and finally also in the derived dose maps. Correct repositioning is paramount when scanning noncylindrical dosimeter phantoms as any repositioning error will give rise to severe imaging artifacts. We hereby propose a different scanning technique that does not require any repositioning of the dosimeter phantom. In this method, no pre-irradiation san is recorded but the dosimeter phantom is scanned twice with light at two different wavelengths. It is demonstrated that this method is accurate in scanning non-cylindrical anthropomorphic shaped phantoms
Pallone, Matthew J.; Poplack, Steven P.; Barth, Richard J., Jr.; Paulsen, Keith D.
2012-02-01
Image-guided wire localization is the current standard of care for the excision of non-palpable carcinomas during breast conserving surgeries (BCS). The efficacy of this technique depends upon the accuracy of wire placement, maintenance of the fixed wire position (despite patient movement), and the surgeon's understanding of the spatial relationship between the wire and tumor. Notably, breast shape can vary significantly between the imaging and surgical positions. Despite this method of localization, re-excision is needed in approximately 30% of patients due to the proximity of cancer to the specimen margins. These limitations make wire localization an inefficient and imprecise procedure. Alternatively, we investigate a method of image registration and finite element (FE) deformation which correlates preoperative supine MRIs with 3D optical scans of the breast surface. MRI of the breast can accurately define the extents of very small cancers. Furthermore, supine breast MR reduces the amount of tissue deformation between the imaging and surgical positions. At the time of surgery, the surface contour of the breast may be imaged using a handheld 3D laser scanner. With the MR images segmented by tissue type, the two scans are approximately registered using fiducial markers present in both acquisitions. The segmented MRI breast volume is then deformed to match the optical surface using a FE mechanical model of breast tissue. The resulting images provide the surgeon with 3D views and measurements of the tumor shape, volume, and position within the breast as it appears during surgery which may improve surgical guidance and obviate the need for wire localization.
Optical-CT 3D Dosimetry Using Fresnel Lenses with Minimal Refractive-Index Matching Fluid.
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 1ltr to 10cc. 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 2h 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.
Optical-CT 3D Dosimetry Using Fresnel Lenses with Minimal Refractive-Index Matching Fluid.
Bache, Steven; Malcolm, Javian; Adamovics, John; Oldham, Mark
2016-01-01
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 1ltr to 10cc). 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 2h 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. PMID:27019460
Optical-CT 3D Dosimetry Using Fresnel Lenses with Minimal Refractive-Index Matching Fluid
Bache, Steven; Malcolm, Javian; Adamovics, John; Oldham, Mark
2016-01-01
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 1ltr to 10cc). 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 2h 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. PMID:27019460
Improved Uav-Borne 3d Mapping by Fusing Optical and Laserscanner Data
Jutzi, B.; Weinmann, M.; Meidow, J.
2013-08-01
In this paper, a new method for fusing optical and laserscanner data is presented for improved UAV-borne 3D mapping. We propose to equip an unmanned aerial vehicle (UAV) with a small platform which includes two sensors: a standard low-cost digital camera and a lightweight Hokuyo UTM-30LX-EW laserscanning device (210 g without cable). Initially, a calibration is carried out for the utilized devices. This involves a geometric camera calibration and the estimation of the position and orientation offset between the two sensors by lever-arm and bore-sight calibration. Subsequently, a feature tracking is performed through the image sequence by considering extracted interest points as well as the projected 3D laser points. These 2D results are fused with the measured laser distances and fed into a bundle adjustment in order to obtain a Simultaneous Localization and Mapping (SLAM). It is demonstrated that an improvement in terms of precision for the pose estimation is derived by fusing optical and laserscanner data.
Non-linear dynamic analysis of ancient masonry structures by 3D rigid block models
Orduña, Agustin; Ayala, A. Gustavo
2015-12-01
This work presents a formulation for non-linear dynamic analysis of unreinforced masonry structures using rigid block models. This procedure is akin to the distinct element family of methods, nevertheless, we assume that small displacements occur and, therefore, the formulation does not involve the search for new contacts between blocks. This proposal is also related to the rigid element method, although, in this case we use full three-dimensional models and a more robust interface formulation.
Nonlinear Synchronization for Automatic Learning of 3D Pose Variability in Human Motion Sequences
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.
Fabrication of fully undercut ZnO-based photonic crystal membranes with 3D optical confinement
Hoffmann, Sandro Phil; Albert, Maximilian; Meier, Cedrik
2016-09-01
For studying nonlinear photonics, a highly controllable emission of photons with specific properties is essential. Two-dimensional photonic crystals (PhCs) have proven to be an excellent candidate for manipulating photon emission due to resonator-based effects. Additionally, zinc oxide (ZnO) has high susceptibility coefficients and therefore shows pronounced nonlinear effects. However, in order to fabricate such a cavity, a fully undercut ZnO membrane is required, which is a challenging problem due to poor selectivity of the known etching chemistry for typical substrates such as sapphire or ZnO. The aim of this paper is to demonstrate and characterize fully undercut photonic crystal membranes based on a thin ZnO film sandwiched between two layers of silicon dioxide (SiO2) on silicon substrates, from the initial growth of the heterostructure throughout the entire fabrication process. This process leads to a fully undercut ZnO-based membrane with adjustable optical confinement in all three dimensions. Finally, photonic resonances within the tailored photonic band gap are achieved due to optimized PhC-design (in-plane) and total internal reflection in the z-direction. The presented approach enables a variety of photon based resonator structures in the UV regime for studying nonlinear effects, including photon-exciton coupling and all-optical switching.
3DTouch: A wearable 3D input device with an optical sensor and a 9-DOF inertial measurement unit
Nguyen, Anh; Banic, Amy
2014-01-01
We present 3DTouch, a novel 3D wearable input device worn on the fingertip for 3D manipulation tasks. 3DTouch is designed to fill the missing gap of a 3D input device that is self-contained, mobile, and universally working across various 3D platforms. This paper presents a low-cost solution to designing and implementing such a device. Our approach relies on relative positioning technique using an optical laser sensor and a 9-DOF inertial measurement unit. 3DTouch is self-contained, and design...
Stone, Adam; Jain, Himanshu; Dierolf, Volkmar; Sakakura, Masaaki; Shimotsuma, Yasuhiko; Miura, Kiyotaka; Hirao, Kazuyuki; Lapointe, Jerome; Kashyap, Raman
2015-05-01
Direct three-dimensional laser writing of amorphous waveguides inside glass has been studied intensely as an attractive route for fabricating photonic integrated circuits. However, achieving essential nonlinear-optic functionality in such devices will also require the ability to create high-quality single-crystal waveguides. Femtosecond laser irradiation is capable of crystallizing glass in 3D, but producing optical-quality single-crystal structures suitable for waveguiding poses unique challenges that are unprecedented in the field of crystal growth. In this work, we use a high angular-resolution electron diffraction method to obtain the first conclusive confirmation that uniform single crystals can be grown inside glass by femtosecond laser writing under optimized conditions. We confirm waveguiding capability and present the first quantitative measurement of power transmission through a laser-written crystal-in-glass waveguide, yielding loss of 2.64 dB/cm at 1530 nm. We demonstrate uniformity of the crystal cross-section down the length of the waveguide and quantify its birefringence. Finally, as a proof-of-concept for patterning more complex device geometries, we demonstrate the use of dynamic phase modulation to grow symmetric crystal junctions with single-pass writing.
Landmark papers on photorefractive nonlinear optics
Yeh, Pochi
1995-01-01
This book, intended for students, researchers and engineers, is a collection of classic papers on photorefractive nonlinear optics. Included are landmark papers on fundamental photorefractive phenomena, two-wave mixing, four-wave mixing, phase conjugators and resonators, material growth and physics, and applications in image processing, optical storage and optical computing.
Ring for test of nonlinear integrable optics
Valishev, A; Kashikhin, V; Danilov, V
2011-01-01
Nonlinear optics is a promising idea potentially opening the path towards achieving super high beam intensities in circular accelerators. Creation of a tune spread reaching 50% of the betatron tune would provide strong Landau damping and make the beam immune to instabilities. Recent theoretical work has identified a possible way to implement stable nonlinear optics by incorporating nonlinear focusing elements into a specially designed machine lattice. In this report we propose the design of a test accelerator for a proof-of-principle experiment. We discuss possible studies at the machine, requirements on the optics stability and sensitivity to imperfections.
Nonlinear soliton matching between optical fibers
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......NL to demonstrate a significant soliton selffrequency shift of a fundamental soliton, and we show that nonlinear matching can take precedence over linear mode matching. The nonlinear coupling coefficient depends on both the dispersion (β2) and nonlinearity (γ), as well as on the power coupling...
Axial-Stereo 3-D Optical Metrology for Inner Profile of Pipes Using a Scanning Laser Endoscope
Gong, Yuanzheng; Johnston, Richard S.; Melville, C. David; Seibel, Eric J.
2015-07-01
As the rapid progress in the development of optoelectronic components and computational power, 3-D 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 article proposed a new approach to measure tiny internal 3-D 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 3-D data as ground truth, and the quantification was analyzed by Iterative Closest Points algorithm.
3D simulations of supernova remnants evolution including non-linear particle acceleration
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...
Simulation of 3D tumor cell growth using nonlinear finite element method.
Dong, Shoubing; Yan, Yannan; Tang, Liqun; Meng, Junping; Jiang, Yi
2016-06-01
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. PMID:26213205
Nonlinear stability analysis of 3D Couette flow considering energy transfer conservation
The transition from laminar plane Couette flow to intermittency is studied within a 108-dimensional Galerkin representation of Orr-Sommerfeld and Squire modes. A distinct transient behaviour is found in the Reynolds number region 325≤R≤350. The results also confirm the sensitive dependence on initial conditions in the intermittency regime as recently found in a higher-dimensional function space. As a crucial point, the conservation of the overall energy-transfer rate is rigorously implemented by renormalizing the nonlinear coefficients of the Galerkin system. As a consequence, there are no runaway trajectories in the cut-off system considered. Surprisingly, further consistency conditions were found in the quadratic terms of the time derivative of the kinetic energy. After they have been taken into account by the renormalization, a quantitatively good fulfillment of the energy balances is achieved
Numerical and Experimental Verification of a 3D Quasi-Optical System
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.
A 3D optical head motion measurement system and its primary application in stereotactic radiosurgery
Head motion is a significant source of therapy-effect degradation in stereotactic radiosurgery (SRS). In this study, a 3D optical head motion measurement system with a precision less than 0.1 mm has been developed by our group. During the clinical SRS treatment experiments, three dimensional (3D) positions of infrared light emission diode (ILED) markers on the head-chin, nose tip, forehead and ear were measured with a data sampling rate of once per second for 30 minutes, in frame and frameless sessions, respectively, by this system. The t-test and linear correlation analysis have been used, and the results indicate that the difference of head motion with moldable thermoplastic frame on and without frame was highly statistically significant (p<0.01), and the fixation of the moldable thermoplastic frame in X axial direction (defined in local treatment-couch coordinate system) needs to be reinforced to realize better fixation effect for high degree of treatment precision. It is also shown that the head motion was mainly due to the rotation about the occiput-couch contact point, however, the chin is the most easily movable area on the head. The result implies that in the newly developing frameless SRS treatment, the landmarkers should be attached to the relatively static areas such as forehead and ear. (author)
Nonlinear optical properties of an azobenzene polymer
The nonlinear optical properties of an azobenzene polymer azo12—MO were investigated by a Z-scan technique. The polymer was synthesized by assembling the liquid-crystalline polymer azo12 with methyl orange. The nonlinear refractive index (1.39 × 10−15 cm2/W) and the nonlinear absorption coefficient (0.11 cm/GW) of azo12—MO were determined with 532-nm picosecond laser pulses at the irradiance of 92.40 GW/cm2. When compared to the nonlinear properties of azo12 and methyl orange, azo12—MO possesses the advantages of its two constituents and shows larger nonlinear optical properties. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
WebTOP: Interactive 3D Web-based Simulations for Teaching Waves and Optics
Mzoughi, Taha; Foley, John; Herring, Davis; Morris, Matt; Wyser, Ben
2003-03-01
WebTOP is 3D interactive computer graphics system designed to help students learn about waves and optics. It has been used to help teach undergraduate introductory physics and optics classes. It has sixteen modules that treat the following topics: waves, geometrical optics, reflection and refraction, polarization, interference, diffraction, lasers and scattering. WebTOP simulations have the following characteristics. First, they are three dimensional, i.e., they have navigation controls that allow the user to rotate the scene, pan it, or zoom into it. Secondly, they are interactive. The user can change the parameters either by typing the values into boxes, or by using the mouse cursor to move the corresponding widget in the scene. Thirdly, the simulations are animated, when animation is appropriate. Furthermore, the simulations include vcr-type controls that allow the user to record a session for later retrieval and viewing. Finally, these modules run inside a web browser. They can be run from our website, http://webtop.msstate.edu or be downloaded from this website and run locally. In addition to the simulations, each WebTOP module includes a short description of the theory used, and sets of recorded examples and suggested exercises. WebTOP is sponsored in part by the National Science Foundation (DUE 9950569).
3D micro-optical elements for generation of tightly focused vortex beams
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.
Topology optimization of nonlinear optical devices
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...... incremental complex Newton–Raphson scheme is used to solve the nonlinear equations. The sensitivities of the objective function with respect to element-wise design variables are found using an adjoint approach and iterative design updates are performed using the method of moving asymptotes. The optimization...... procedure is exemplified by the design of two nonlinear devices. A one-dimensional optical diode is created by distributing a linear and a nonlinear material. The diode allows for higher transmission in one propagation direction compared to the other. The second example illustrates a two-dimensional optical...
Analytical models of icosahedral shells for 3D optical imaging of viruses
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 ...
Surface roughness characterization of cast components using 3D optical methods
Nwaogu, Ugochukwu Chibuzoh; Tiedje, Niels Skat; Hansen, Hans Nørgaard
scanning probe image processor (SPIP) software and the results of the surface roughness parameters obtained were subjected to statistical analyses. The bearing area ratio was introduced and applied to the surface roughness analysis. From the results, the surface quality of the standard comparators is......A novel method that applies a non-contact technique using a 3D optical system to measure the roughness of selected standard surface roughness comparators used in the foundry industry is presented. This method is described in detail in the paper. Profile and area analyses were performed using...... made in green sand moulds and the surface roughness parameter (Sa) values were compared with those of the standards. Sa parameter suffices for the evaluation of casting surface texture. The S series comparators showed a better description of the surface of castings after shot blasting than the A series...
3D optical phase reconstruction within PMMA samples using a spectral OCT system
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.
Modeling of Nonlinear Mechanical Behavior for 3D Needled C/C-SiC Composites Under Tensile Load
Xie, Junbo; Fang, Guodong; Chen, Zhen; Liang, Jun
2016-04-01
This paper established a macroscopic constitutive model to describe the nonlinear stress-strain behavior of 3D needled C/C-SiC composites under tensile load. Extensive on- and off-axis tensile tests were performed to investigate the macroscopic mechanical behavior and damage characteristics of the composites. The nonlinear mechanical behavior of the material was mainly induced by matrix tensile cracking and fiber/matrix debonding. Permanent deformations and secant modulus degradation were observed in cyclic loading-unloading tests. The nonlinear stress-strain relationship of the material could be described macroscopically by plasticity deformation and stiffness degradation. In the proposed model, we employed a plasticity theory with associated plastic flow rule to describe the evolution of plastic strains. A novel damage variable was also introduced to characterize the stiffness degradation of the material. The damage evolution law was derived from the statistical distribution of material strength. Parameters of the proposed model can be determined from off-axis tensile tests. Stress-strain curves predicted by this model showed reasonable agreement with experimental results.
Modeling of Nonlinear Mechanical Behavior for 3D Needled C/C-SiC Composites Under Tensile Load
Xie, Junbo; Fang, Guodong; Chen, Zhen; Liang, Jun
2016-08-01
This paper established a macroscopic constitutive model to describe the nonlinear stress-strain behavior of 3D needled C/C-SiC composites under tensile load. Extensive on- and off-axis tensile tests were performed to investigate the macroscopic mechanical behavior and damage characteristics of the composites. The nonlinear mechanical behavior of the material was mainly induced by matrix tensile cracking and fiber/matrix debonding. Permanent deformations and secant modulus degradation were observed in cyclic loading-unloading tests. The nonlinear stress-strain relationship of the material could be described macroscopically by plasticity deformation and stiffness degradation. In the proposed model, we employed a plasticity theory with associated plastic flow rule to describe the evolution of plastic strains. A novel damage variable was also introduced to characterize the stiffness degradation of the material. The damage evolution law was derived from the statistical distribution of material strength. Parameters of the proposed model can be determined from off-axis tensile tests. Stress-strain curves predicted by this model showed reasonable agreement with experimental results.
Nonlinear optical localization in embedded chalcogenide waveguide arrays
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.
Linear Stability and Nonlinear Evolution of 3D Vortices in Rotating Stratified Flows
Mahdinia, Mani; Hassanzadeh, Pedram; Marcus, Philip
2014-11-01
Axisymmetric Gaussian vortices are widely-used to model oceanic vortices. We study their stability in rotating, stratified flows by using the full Boussinesq equations. We created a stability map as a function of the Burger and Rossby numbers of the vortices. We computed the linear growth rates of the most-unstable eigenmodes and their corresponding eigenmodes. Our map shows a significant cyclone/anti-cyclone asymmetry. The vortices are linearly unstable in most of the parameter space that we studied. However, the anticyclonic vortices, over most of the parameter space, have eigenmodes with only very weak growth rates - longer than 50 vortex turn-around times. For oceanic vortices, that time corresponds to several months, so we argue that this slow growth rate means that the oceanic anticyclones lifetimes are not determined by linear stability, but by other processes. We also use our full, nonlinear simulations to show an example of an unstable cyclone with a very fast growing linear eigenmodes. However, we show that cyclone quickly redistributes its vorticity and becomes a stable tripole with a large core that is nearly axisymmetric.
The NCOREL computer program for 3D nonlinear supersonic potential flow computations
Siclari, M. J.
1983-01-01
An innovative computational technique (NCOREL) was established for the treatment of three dimensional supersonic flows. The method is nonlinear in that it solves the nonconservative finite difference analog of the full potential equation and can predict the formation of supercritical cross flow regions, embedded and bow shocks. The method implicitly computes a conical flow at the apex (R = 0) of a spherical coordinate system and uses a fully implicit marching technique to obtain three dimensional cross flow solutions. This implies that the radial Mach number must remain supersonic. The cross flow solutions are obtained by using type dependent transonic relaxation techniques with the type dependency linked to the character of the cross flow velocity (i.e., subsonic/supersonic). The spherical coordinate system and marching on spherical surfaces is ideally suited to the computation of wing flows at low supersonic Mach numbers due to the elimination of the subsonic axial Mach number problems that exist in other marching codes that utilize Cartesian transverse marching planes.
Quantum nonlinear optics — photon by photon
Chang, Darrick E.; Vuletić, Vladan; Lukin, Mikhail D.
2014-01-01
The realization of strong interactions between individual photons is a long-standing goal of both fundamental and technological significance. Scientists have known for over half a century that light fields can interact inside nonlinear optical media, but the nonlinearity of conventional materials is negligible at the light powers associated with individual photons. Nevertheless, remarkable advances in quantum optics have recently culminated in the demonstration of several methods for generati...
Beyond optical molasses: 3D raman sideband cooling of atomic cesium to high phase-space density
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. PMID:11015933
Non-linear dynamics of viscous bilayers subjected to an electric field: 3D phase field simulations
Dritselis, Christos; Karapetsas, George; Bontozoglou, Vasilis
2014-11-01
The scope of this work is to investigate the non-linear dynamics of the electro-hydrodynamic instability of a bilayer of immiscible liquids. We consider the case of two viscous films which is separated from the top electrode by air. We assume that the liquids are perfect dielectrics and consider the case of both flat and patterned electrodes. We develop a computational model using the diffuse interface method and carry out 3D numerical simulations fully accounting for the flow and electric field in all phases. We perform a parametric study and investigate the influence of the electric properties of fluids, applied voltage and various geometrical characteristics of the mask. The authors acknowledge the support by the General Secretariat of Research and Technology of Greece under the action ``Supporting Postdoctoral Researchers'' (Grant Number PE8/906), co-funded by the European Social Fund and National Resources.
Automatic registration of optical imagery with 3d lidar data using local combined mutual information
Parmehr, E. G.; Fraser, C. S.; Zhang, C.; Leach, J.
2013-10-01
Automatic registration of multi-sensor data is a basic step in data fusion for photogrammetric and remote sensing applications. The effectiveness of intensity-based methods such as Mutual Information (MI) for automated registration of multi-sensor image has been previously reported for medical and remote sensing applications. In this paper, a new multivariable MI approach that exploits complementary information of inherently registered LiDAR DSM and intensity data to improve the robustness of registering optical imagery and LiDAR point cloud, is presented. LiDAR DSM and intensity information has been utilised in measuring the similarity of LiDAR and optical imagery via the Combined MI. An effective histogramming technique is adopted to facilitate estimation of a 3D probability density function (pdf). In addition, a local similarity measure is introduced to decrease the complexity of optimisation at higher dimensions and computation cost. Therefore, the reliability of registration is improved due to the use of redundant observations of similarity. The performance of the proposed method for registration of satellite and aerial images with LiDAR data in urban and rural areas is experimentally evaluated and the results obtained are discussed.
A 3D approach to reconstruct continuous optical images using lidar and MODIS
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.
3D reconstruction and characterization of laser induced craters by in situ optical microscopy
Casal, A.; Cerrato, R.; Mateo, M. P.; Nicolas, G.
2016-06-01
A low-cost optical microscope was developed and coupled to an irradiation system in order to study the induced effects on material during a multipulse regime by an in situ visual inspection of the surface, in particular of the spot generated at different pulses. In the case of laser ablation, a reconstruction of the crater in 3D was made from the images of the sample surface taken during the irradiation process, and the subsequent profiles of ablated material were extracted. The implementation of this homemade optical device gives an added value to the irradiation system, providing information about morphology evolution of irradiated area when successive pulses are applied. In particular, the determination of ablation rates in real time can be especially useful for a better understanding and controlling of the ablation process in applications where removal of material is involved, such as laser cleaning and in-depth characterization of multilayered samples and diffusion processes. The validation of the developed microscope was made by a comparison with a commercial confocal microscope configured for the characterization of materials where similar results of crater depth and diameter were obtained for both systems.
Super non-linear RRAM with ultra-low power for 3D vertical nano-crossbar arrays.
Luo, Qing; Xu, Xiaoxin; Liu, Hongtao; Lv, Hangbing; Gong, Tiancheng; Long, Shibing; Liu, Qi; Sun, Haitao; Banerjee, Writam; Li, Ling; Gao, Jianfeng; Lu, Nianduan; Liu, Ming
2016-08-25
Vertical crossbar arrays provide a cost-effective approach for high density three-dimensional (3D) integration of resistive random access memory. However, an individual selector device is not allowed to be integrated with the memory cell separately. The development of V-RRAM has impeded the lack of satisfactory self-selective cells. In this study, we have developed a high performance bilayer self-selective device using HfO2 as the memory switching layer and a mixed ionic and electron conductor as the selective layer. The device exhibits high non-linearity (>10(3)) and ultra-low half-select leakage (<0.1 pA). A four layer vertical crossbar array was successfully demonstrated based on the developed self-selective device. High uniformity, ultra-low leakage, sub-nA operation, self-compliance, and excellent read/write disturbance immunity were achieved. The robust array level performance shows attractive potential for low power and high density 3D data storage applications. PMID:27510434
Infiltrated microstructured fibers as tunable and nonlinear optical devices
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.......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....
The Traveling Optical Scanner – Case Study on 3D Shape Models of Ancient Brazilian Skulls
Trinderup, Camilla Himmelstrup; Dahl, Vedrana Andersen; Gregersen, Kristian Murphy;
2016-01-01
, inoffensive and inexpensive 3D scanning modality based on structured light, suitable for capturing the morphology and the appearance of specimens. Benefits of having 3D models are manifold. The 3D models are easy to share among researchers and can be made available to the general public. Advanced...
Completely integrable models of nonlinear optics
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.
Scale-invariant nonlinear optics in gases
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.
Real-time 3D Fourier-domain optical coherence tomography guided microvascular anastomosis
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.
Optical Measurement of Micromechanics and Structure in a 3D Fibrin Extracellular Matrix
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
Nonlinear Integrated Optical Waveguides in Chalcogenide Glasses
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.
SURFACE SYMMETRY RESOLUTION OF NONLINEAR OPTICAL TECHNIQUES
KOOPMANS, B; VANDERWOUDE, F; SAWATZKY, GA
1992-01-01
A general rule is derived, relating the order of a nonlinear optical process to the highest possible symmetry which can be resolved in a rotational analysis. We show that with an Nth order optical technique, rotational anisotropy can be observed only up to (N + L)-fold rotational symmetry, where L i
A prototype fan-beam optical CT scanner for 3D dosimetry
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, λ = 543 nm) with line-generating lens, and a laser diode module (LDM, λ = 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 PRESAGETM 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 ∼40% in magnitude. The flask registration
Mesoscale Engineering of Nanocomposite Nonlinear Optical Materials
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
Optical rogue waves and soliton turbulence in nonlinear fibre optics
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....
Exact surface registration of retinal surfaces from 3-D optical coherence tomography images.
Lee, Sieun; Lebed, Evgeniy; Sarunic, Marinko V; Beg, Mirza Faisal
2015-02-01
Nonrigid registration of optical coherence tomography (OCT) images is an important problem in studying eye diseases, evaluating the effect of pharmaceuticals in treating vision loss, and performing group-wise cross-sectional analysis. High dimensional nonrigid registration algorithms required for cross-sectional and longitudinal analysis are still being developed for accurate registration of OCT image volumes, with the speckle noise in images presenting a challenge for registration. Development of algorithms for segmentation of OCT images to generate surface models of retinal layers has advanced considerably and several algorithms are now available that can segment retinal OCT images into constituent retinal surfaces. Important morphometric measurements can be extracted if accurate surface registration algorithm for registering retinal surfaces onto corresponding template surfaces were available. In this paper, we present a novel method to perform multiple and simultaneous retinal surface registration, targeted to registering surfaces extracted from ocular volumetric OCT images. This enables a point-to-point correspondence (homology) between template and subject surfaces, allowing for a direct, vertex-wise comparison of morphometric measurements across subject groups. We demonstrate that this approach can be used to localize and analyze regional changes in choroidal and nerve fiber layer thickness among healthy and glaucomatous subjects, allowing for cross-sectional population wise analysis. We also demonstrate the method's ability to track longitudinal changes in optic nerve head morphometry, allowing for within-individual tracking of morphometric changes. This method can also, in the future, be used as a precursor to 3-D OCT image registration to better initialize nonrigid image registration algorithms closer to the desired solution. PMID:25312906
2D and 3D micro-XRF based on polycapillary optics at XLab Frascati
Polese, C.; Cappuccio, G.; Dabagov, S. B.; Hampai, D.; Liedl, A.; Pace, E.
2015-08-01
XRF imaging spectrometry is a powerful tool for materials characterization. A high spatial resolution is often required, in order to appreciate very tiny details of the studied object. With respect to simple pinholes, polycapillary optics allows much more intense fluxes to be achieved. This is fundamental to detect elements in trace and to strongly reduce the global acquisition time that is actually among the main reasons, in addition to radioprotection issues, affecting the competitiveness of XRF imaging with respect to other faster imaging techniques such as multispectral imaging. Unlike other well-known X-ray optics, principally employed for high brilliant radiation source such as synchrotron facilities, polyCO can be efficiently coupled also with conventional X-ray tubes. All these aspects make them the most suitable choice to realize portable, safe and high performing μXRF spectrometers. In this work preliminary results achieved with a novel 2D and 3D XRF facility, called Rainbow X-Ray (RXR), are reported, with particular attention to the spatial resolution achieved. RXR is based on the confocal arrangement of three polycapillary lenses, one focusing the primary beam and the other two capturing the fluorescence signal. The detection system is split in two couples of lens-detector in order to cover a wider energy range. The entire device is a laboratory user-friendly facility and, though it allows measurements on medium-size objects, its dimensions do not preclude it to be transported for in situ analysis on request, thanks also to a properly shielded cabinet.
3-D nuclear analysis of the final optics of a laser driven fusion power plant
In the High Average Power Laser (HAPL) program, power plant designs are assessed with 350 MJ yield targets driven by 40 KrF laser beams. The final optics system that focuses the laser onto the target includes a grazing incidence metallic mirror (GIMM) located at 24 m from the target with 85 angle of incidence. The GIMM is in direct line of sight of the target and has a 50 microns thick aluminum coating. Several options were considered for the substrate material. We performed three-dimensional (3-D) neutronics calculations to assess the impact of the GIMM design options on the nuclear environment at the dielectric focusing and turning mirrors. We used the recently developed MCNPX-CGM Monte Carlo code that allows performing the neutronics calculations directly in the exact CAD model. The most recent continuous energy fusion evaluated nuclear data library (FENDL-2.1) was used. One of the 40 beamlines was modeled with surrounding reflective boundaries. We considered beam duct configuration modifications such as utilizing neutron traps behind the mirrors to reduce radiation streaming. Several variance reduction techniques were utilized to reduce the statistical uncertainties. The results indicate that material choice and thickness for the GIMM impact the nuclear environment at all mirrors. The neutron flux and nuclear heating at the dielectric mirrors are a factor of ∝1.6 higher when AlBeMet is used instead of SiC as substrate in the GIMM. The fast neutron flux decreases by about two orders of magnitude as one moves from the GIMM to the focusing mirror with an additional two orders of magnitude attenuation at the turning mirror accompanied with significant spectrum softening. In this paper, the details of the analysis and results will be presented and the expected optics lifetime will be assessed. (orig.)
Wang, Cuihuan; Kim, Leonard; Barnard, Nicola; Khan, Atif; Pierce, Mark C.
2016-02-01
Our long term goal is to develop a high-resolution imaging method for comprehensive assessment of tissue removed during lumpectomy procedures. By identifying regions of high-grade disease within the excised specimen, we aim to develop patient-specific post-operative radiation treatment regimens. We have assembled a benchtop spectral-domain optical coherence tomography (SD-OCT) system with 1320 nm center wavelength. Automated beam scanning enables "sub-volumes" spanning 5 mm x 5 mm x 2 mm (500 A-lines x 500 B-scans x 2 mm in depth) to be collected in under 15 seconds. A motorized sample positioning stage enables multiple sub-volumes to be acquired across an entire tissue specimen. Sub-volumes are rendered from individual B-scans in 3D Slicer software and en face (XY) images are extracted at specific depths. These images are then tiled together using MosaicJ software to produce a large area en face view (up to 40 mm x 25 mm). After OCT imaging, specimens were sectioned and stained with HE, allowing comparison between OCT image features and disease markers on histopathology. This manuscript describes the technical aspects of image acquisition and reconstruction, and reports initial qualitative comparison between large area en face OCT images and HE stained tissue sections. Future goals include developing image reconstruction algorithms for mapping an entire sample, and registering OCT image volumes with clinical CT and MRI images for post-operative treatment planning.
Attota, Ravi Kiran; Weck, Peter; Kramar, John A; Bunday, Benjamin; Vartanian, Victor
2016-07-25
In-line metrologies currently used in the semiconductor industry are being challenged by the aggressive pace of device scaling and the adoption of novel device architectures. Metrology and process control of three-dimensional (3-D) high-aspect-ratio (HAR) features are becoming increasingly important and also challenging. In this paper we present a feasibility study of through-focus scanning optical microscopy (TSOM) for 3-D shape analysis of HAR features. TSOM makes use of 3-D optical data collected using a conventional optical microscope for 3-D shape analysis. Simulation results of trenches and holes down to the 11 nm node are presented. The ability of TSOM to analyze an array of HAR features or a single isolated HAR feature is also presented. This allows for the use of targets with area over 100 times smaller than that of conventional gratings, saving valuable real estate on the wafers. Indications are that the sensitivity of TSOM may match or exceed the International Technology Roadmap for Semiconductors (ITRS) measurement requirements for the next several years. Both simulations and preliminary experimental results are presented. The simplicity, lowcost, high throughput, and nanometer scale 3-D shape sensitivity of TSOM make it an attractive inspection and process monitoring solution for nanomanufacturing. PMID:27464112
Complex geometrical optics of nonlinear inhomogeneous fibres
This paper analyses the Gaussian beam (GB) evolution in nonlinear fibres with special attention given to the influence of the initial curvature of the wavefront and to the fibres' permittivity profile. The analysis is performed in the framework of paraxial complex geometrical optics (PCGO). This method reduces the problem of GB evolution in nonlinear and inhomogeneous media to the solution of ordinary differential equations, which can be easily solved either analytically or numerically. It is shown that the PCGO approach radically simplifies modelling of nonlinear phenomena in fibres as compared with standard methods of nonlinear optics such as the variational method approach and the method of moments. It is shown that the PCGO method readily supplies the solution of the nonlinear Schrödinger equation (NLS) for a self-focusing fibre with a focusing permittivity profile and provides a number of new results. The discussion on the interplay between the nonlinear (self-focusing and self-defocusing) and linear (focusing and defocusing) components of the total permittivity demonstrates the new possibilities to limit the collapse phenomenon in nonlinear fibres of Kerr type taking into account the effect of initial beam divergence
Complex geometrical optics of nonlinear inhomogeneous fibres
Berczynski, Pawel
2011-03-01
This paper analyses the Gaussian beam (GB) evolution in nonlinear fibres with special attention given to the influence of the initial curvature of the wavefront and to the fibres' permittivity profile. The analysis is performed in the framework of paraxial complex geometrical optics (PCGO). This method reduces the problem of GB evolution in nonlinear and inhomogeneous media to the solution of ordinary differential equations, which can be easily solved either analytically or numerically. It is shown that the PCGO approach radically simplifies modelling of nonlinear phenomena in fibres as compared with standard methods of nonlinear optics such as the variational method approach and the method of moments. It is shown that the PCGO method readily supplies the solution of the nonlinear Schrödinger equation (NLS) for a self-focusing fibre with a focusing permittivity profile and provides a number of new results. The discussion on the interplay between the nonlinear (self-focusing and self-defocusing) and linear (focusing and defocusing) components of the total permittivity demonstrates the new possibilities to limit the collapse phenomenon in nonlinear fibres of Kerr type taking into account the effect of initial beam divergence.
Accuracy of optical scanning methods of the Cerec®3D system in the process of making ceramic inlays
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.
Creation of quantum-degenerate gases of ytterbium in a compact 2D-/3D-magneto-optical trap setup
Doerscher, Soeren; Thobe, Alexander; Hundt, Bastian; Kochanke, Andre; Le Targat, Rodolphe; Windpassinger, Patrick; Becker, Christoph; Sengstock, Klaus [Institut fuer Laserphysik, Zentrum fuer Optische Quantentechnologien, Universitaet Hamburg, Hamburg 22761 (Germany)
2013-04-15
We report on the first experimental setup based on a 2D-/3D-magneto-optical trap (MOT) scheme to create both Bose-Einstein condensates and degenerate Fermi gases of several ytterbium isotopes. Our setup does not require a Zeeman slower and offers the flexibility to simultaneously produce ultracold samples of other atomic species. Furthermore, the extraordinary optical access favors future experiments in optical lattices. A 2D-MOT on the strong {sup 1}S{sub 0}{yields}{sup 1}P{sub 1} transition captures ytterbium directly from a dispenser of atoms and loads a 3D-MOT on the narrow {sup 1}S{sub 0}{yields}{sup 3}P{sub 1} intercombination transition. Subsequently, atoms are transferred to a crossed optical dipole trap and cooled evaporatively to quantum degeneracy.
Creation of quantum-degenerate gases of ytterbium in a compact 2D-/3D-magneto-optical trap setup.
Dörscher, Sören; Thobe, Alexander; Hundt, Bastian; Kochanke, André; Le Targat, Rodolphe; Windpassinger, Patrick; Becker, Christoph; Sengstock, Klaus
2013-04-01
We report on the first experimental setup based on a 2D-/3D-magneto-optical trap (MOT) scheme to create both Bose-Einstein condensates and degenerate Fermi gases of several ytterbium isotopes. Our setup does not require a Zeeman slower and offers the flexibility to simultaneously produce ultracold samples of other atomic species. Furthermore, the extraordinary optical access favors future experiments in optical lattices. A 2D-MOT on the strong (1)S0 → (1)P1 transition captures ytterbium directly from a dispenser of atoms and loads a 3D-MOT on the narrow (1)S0 → (3)P1 intercombination transition. Subsequently, atoms are transferred to a crossed optical dipole trap and cooled evaporatively to quantum degeneracy. PMID:23635183
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)
Integrated optical devices using bacteriorhodopsin as active nonlinear optical material
Dér, A; Fábián, L.; Valkai, S.; Wolff, E.; Ramsden, Jeremy J.; Ormos, P.
2006-01-01
Coupling of optical data-processing devices with microelectronics, telecocommunication and sensory functions, is among the biggest challenges in molecular electronics. Intensive research is going on to find suitable nonlinear optical materials that could meet the demanding requirements of optoelectronic applications, especially regarding high sensitivity and stability. In addition to inorganic and organic crystals, biological molecules have also been considered for use in in...
Rotational Doppler effect in nonlinear optics
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.
Berczynski, P.; Bliokh, K. Yu.; Kravtsov, Yu. A.; Stateczny, A.
2005-01-01
The paper presents an ab initio account of the paraxial complex geometrical optics (CGO) in application to a scalar Gaussian beam propagation and diffraction in a 3D smoothly inhomogeneous medium. The paraxial CGO deals with quadratic expansion of the complex eikonal and reduces the wave problem to the solution of ordinary differential equations of Riccati type. This substantially simplifies description of Gaussian beams diffraction as compared to full wave or parabolic (quasi-optics) equatio...
Dynamic diffraction-limited light-coupling of 3D-maneuvered wave-guided optical waveguides
Villangca, Mark Jayson; Bañas, Andrew Rafael; Palima, Darwin;
2014-01-01
We have previously proposed and demonstrated the targeted-light delivery capability of wave-guided optical waveguides (WOWs). As the WOWs are maneuvered in 3D space, it is important to maintain efficient light coupling through the waveguides within their operating volume. We propose the use of...
Using optically scanned 3D data in the restoration of Michelangelo's David
Scopigno, Roberto; Cignoni, Paolo; Callieri, Marco; Ganovelli, Fabio; Impoco, G.; Pingi, P.; Ponchio, F.
2003-10-01
Modern 3D scanning technologies allow to reconstruct 3D digital representations of Cultural Heritage artifacts in a semi-automatic way, characterized by very high accuracy and wealth of details. The availability of an accurate digital representation opens several possibilities of utilization to experts (restorers, archivists, museum curators), or to ordinary people (students, museum visitors). 3D scanned data are commonly used for the production of animations, interactive visualizations, or virtual reality applications. A much more exciting opportunity is to use these data in the restoration of Cultural Heritage artworks. The integration between 3D graphic and restoration represents an open research field where many new supporting tools are required; the David restoration project has given several starting points and guidelines to the definition and development of innovative solutions. Digital 3D models can be used in two different but not subsidiary modes: as an instrument for the execution of specific investigations and as a supporting media for the archival and integration of all the restoration-related information, gathered with the different studies and analysis performed on the artwork. In this paper we present some recent work done in the framework of the Michelangelo's David restoration project. A 3D model of the David was reconstructed by the Digital Michelangelo Project, using laser-based 3D scanning technology. We have developed some tools to make those data accessible and useful in the restoration. Preliminary results are reported here together with some directions for further research.
Cooper, W. A.; Graves, J. P.; Duval, B. P.; Porte, L.; Reimerdes, H.; Sauter, O.; Tran, T.-M.
2015-12-01
> Novel free boundary magnetohydrodynamic equilibrium states with spontaneous three-dimensional (3-D) deformations of the plasma-vacuum interface are computed. The structures obtained look like saturated ideal external kink/peeling modes. Large edge pressure gradients yield toroidal mode number distortions when the edge bootstrap current is large and higher corrugations when this current is small. Linear ideal MHD stability analyses confirm the nonlinear saturated ideal kink equilibrium states produced and we can identify the Pfirsch-Schlüter current as the main linear instability driving mechanism when the edge pressure gradient is large. The dominant non-axisymmetric component of this Pfirsch-Schlüter current drives a near resonant helical parallel current density ribbon that aligns with the near vanishing magnetic shear region caused by the edge bootstrap current. This current ribbon is a manifestation of the outer mode previously found on JET (Solano 2010). We claim that the equilibrium corrugations describe structures that are commonly observed in quiescent H-mode tokamak discharges.
Lu, W; Joshi, C; Mori, W B; Silva, L O; Tsung, F S; Tzoufras, M; Vieira, J
2006-01-01
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 30f sec, 200T W laser interacting with a 0.75cm long plasma with density 1.5*10^18 cm^-3 to produce an ultra-short (10f s) mono-energetic bunch of self-injected electrons at 1.5 GeV with 0.3nC of cha...
Analysis of 3D-printed metal for rapid-prototyped reflective terahertz optics
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.