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Simplex optimization method for illumination design

OPTICS LETTERS 2005年第6期30卷 649-651页

作者： Koshel, RJ Univ Arizona Lambda Res Corp Tucson AZ 85710 USA Univ Arizona Ctr Opt Sci Tucson AZ 85710 USA

A modified simplex optimization method is developed for the design of illumination systems. The simplex method is a judicious choice for illumination optimization because of its robustness and convergence properties. To optimize the simplex method, its four parameters are adjusted dependent on the dimensionality of the space to converge with fewer iterations. This work is presented for the end game, when the optimizer is converging on a local optimum rather than searching for it. Up to a 37% reduction in the number of computations is realized. An example using a compound parabolic concentrator is compared between the standard and the modified simplex methods, providing over 22% improvement in the end game. (C) 2005 Optical Society of America.

关键词： computation methods Illumination Illumination design Nonimaging optics Optical systems Ray tracing

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Quasi-non-diffracting static light sheets generated by holistically optimized pupil masks

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OPTICS LETTERS 2022年第7期47卷 1737-1740页

作者： Tang, Cheng Li, Jianping Chinese Acad Sci Shenzhen Inst Adv Technol Shenzhen Peoples R China Univ Chinese Acad Sci Beijing Peoples R China

Thin and wide light sheets are crucial for light sheet microscopy with wide field of views and near diffraction-limited resolutions. Non-diffracting light sheets feature wide span ranges but often come with strong sidelobes or increased thicknesses. We develop a computational optimization method for creating light sheets that balance the trade-offs between thickness, non-diffracting range and sidelobes. We show in theory and experiment that our optimized mask extends the static light sheet's non-diffracting range by 50% while keeping its sidelobes below the 20% level. (C) 2022 Optica Publishing Group

关键词： computation methods Cylindrical lenses Gaussian beams Light sheet microscopy Phase modulation Spatial light modulators

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Hologram synthesis for photorealistic reconstruction

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2008年第12期25卷 3083-3096页

作者： Janda, Martin Hanak, Ivo Onural, Levent Univ W Bohemia Dept Comp Sci & Engn Plzen 30614 Czech Republic Bilkent Univ Dept Elect & Elect Engn TR-06800 Ankara Turkey

computation of diffraction patterns, and thus holograms, of scenes with photorealistic properties is a highly complicated and demanding process. An algorithm, based primarily on computer graphics methods, for computing full-parallax diffraction patterns of complicated surfaces with realistic texture and reflectivity properties is proposed and tested. The algorithm is implemented on single-CPU, multiple-CPU and CPU platforms. An alternative algorithm, which implements reduced occlusion diffraction patterns for much faster but somewhat lower quality results, is also developed and tested. The algorithms allow GPU-aided calculations and easy parallelization. Both numerical and optical reconstructions are conducted. The results indicate that the presented algorithms compute diffraction patterns that provide successful photorealistic reconstructions;the computation times are acceptable especially on the GPU implementations. (C) 2008 Optical Society of America

关键词： computation methods Holographic recording Light properties Optical fields Ptychography Spatial frequency

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Designing illumination lenses and mirrors by the numerical solution of Monge-Ampere equations

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2015年第11期32卷 2227-2236页

作者： Brix, Kolja Hafizogullari, Yasemin Platen, Andreas Rhein Westfal TH Aachen Inst Geometrie & Prakt Math D-52056 Aachen Germany

We consider the inverse refractor and the inverse reflector problem. The task is to design a free-form lens or a free-form mirror that, when illuminated by a point light source, produces a given illumination pattern on a target. Both problems can be modeled by strongly nonlinear second-order partial differential equations of Monge Ampere type. In [Math. Models methods Appl. Sci. 25, 803 (2015)], the authors have proposed a B-spline collocation method, which has been applied to the inverse reflector problem. Now this approach is extended to the inverse refractor problem. We explain in depth the collocation method and how to handle boundary conditions and constraints. The paper concludes with numerical results of refracting and reflecting optical surfaces and their verification via ray tracing. (C) 2015 Optical Society of America

关键词： Numerical approximation and analysis computation methods Nonspherical lens design Nonspherical mirror surfaces Nonimaging optics Inverse problems

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Distinction of cervical cancer biopsies by use of infrared microspectroscopy and probabilistic neural networks

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APPLIED OPTICS 2005年第18期44卷 3725-3734页

作者： Podshyvalov, A Sahu, RK Mark, S Kantarovich, K Guterman, H Goldstein, J Jagannathan, R Argov, S Mordechai, S Soroka Univ Med Ctr Dept Pathol IL-84105 Beer Sheva Israel Ben Gurion Univ Negev Dept Phys IL-84105 Beer Sheva Israel Ben Gurion Univ Negev Dept Elect & Comp Engn IL-84105 Beer Sheva Israel

Fourier-transform. infrared spectroscopy has shown alterations of spectral characteristics of cells and tissues as a result of carcinogenesis. The research reported here focuses on the diagnosis of cancer in formalin-fixed biopsied tissue for which immunochemistry is not possible and when PAP-smear results are to be confirmed. The data from two groups of patients (a control group and a group of patients diagnosed with cervical cancer) were analyzed. It was found that the glucose/phosphate ratio decreases (by 23-49%) and the RNA/DNA ratio increases (by 38-150%) in carcinogenic compared with normal tissue. Fourier-transform microspectroscopy was used to examine these tissues. This type of study in larger populations may help to set standards or classes with which to use treated biopsied tissue to predict the possibility of cancer. Probabilistic neural networks and statistical tests as parts of these biopsies predict the possibility of cancer with a high degree of accuracy (> 95%). (c) 2005 Optical Society of America

关键词： computation methods Fourier transform infrared spectroscopy Infrared microscopy Infrared radiation Neural networks Wavelet transforms

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Fast focus estimation using frequency analysis in digital holography

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OPTICS EXPRESS 2014年第23期22卷 28926-28933页

作者： Oh, Seungtaik Hwang, Chi-Young Jeong, Il Kwon Lee, Sung-Keun Park, Jae-Hyeung ETRI Taejon 305700 South Korea Inha Univ Sch Informat & Commun Engn Inchon 402751 South Korea

A novel fast frequency-based method to estimate the focus distance of digital hologram for a single object is proposed. The focus distance is computed by analyzing the distribution of intersections of smoothed-rays. The smoothed-rays are determined by the directions of energy flow which are computed from local spatial frequency spectrum based on the windowed Fourier transform. So our method uses only the intrinsic frequency information of the optical field on the hologram and therefore does not require any sequential numerical reconstructions and focus detection techniques of conventional photography, both of which are the essential parts in previous methods. To show the effectiveness of our method, numerical results and analysis are presented as well. (C) 2014 Optical Society of America

关键词： computation methods Digital holographic imaging Fourier transforms Optical flow Photography Spatial frequency

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Dimension-variable invariant imbedding (DVIIM) T-matrix computational method for the light scattering simulation of atmospheric nonspherical particles

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OPTICS EXPRESS 2023年第6期31卷 10052-10069页

作者： Hu Shuai Li Shulei Zeng Qingwei Liu Lei Natl Univ Def Technol Coll Meteorol & Oceanog Changsha 410073 Peoples R China Natl Univ Def Technol Natl Key Lab Electromagnet Environm & Electroopt Changsha 410073 Peoples R China

The invariant imbedding (IIM) T-matrix method has shown great potential in light scattering field. However, the T-matrix need to be calculated through the matrix recurrence formula derived from the Helmholtz equation, thus its computational efficiency is much lower than Extended Boundary Condition Method (EBCM). To alleviate this problem, the Dimension-Variable Invariant Imbedding (DVIIM) T-matrix method is presented in this paper. Compared with the traditional IIM T-matrix model, the dimensions of the T-matrix and relevant matrices are gradually increasing as the iteration performed step by step, thus the unnecessary operations of large matrices can be avoided in early iterations. To optimally determine the dimension of these matrices in each iterative calculation, the spheroid-equivalent scheme (SES) is also proposed. The effectiveness of the DVIIM T-matrix method is validated from the modeling accuracy and calculation efficiency. The simulation results show that compared with traditional T-matrix method, its modeling efficiency can be improved notably, especially for the particles with large size and aspect ratio, where for the spheroid with a aspect ratio of 0.5, the computational time is cut down by 25%. Though the dimension of the T matrix is cut down in the early iterations, the computational precision of DVIIM T-matrix model is not decreased notably, and a good agreement is achieved between the calculation results of DVIIM T-matrix method, IIM T-matrix method and other well-validated models (like EBCM and DDACSAT), where the relative errors of the integral scattering parameters (e.g., extinction, absorption, scattering cross sections) are generally less than 1%. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

关键词： Atmospheric scattering computation methods Forward scattering Light fields Light scattering Particle scattering

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Fast and rigorous optical simulation of periodically corrugated light-emitting diodes based on a diffraction matrix method

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OPTICS EXPRESS 2023年第12期31卷 20410-20423页

作者： Park, Chanhyung Shin, Jeongmin Kim, Sanmun Lee, Songju Park, Juho Park, Jaehyeok Park, Sehong Yoo, Seunghyup Jang, Min Seok Korea Adv Inst Sci & Technol Sch Elect Engn Daejeon 34141 South Korea LG Display OC Opt Technol Task Seoul 07796 South Korea

Increasing the light extraction efficiency has been widely studied for highly efficient organic light-emitting diodes (OLEDs). Among many light-extraction approaches proposed so far, adding a corrugation layer has been considered a promising solution for its simplicity and high effectiveness. While the working principle of periodically corrugated OLEDs can be qualitatively explained by the diffraction theory, dipolar emission inside the OLED structure makes its quantitative analysis challenging, making one rely on finite-element electromagnetic simulations that could require huge computing resources. Here, we demonstrate a new simulation method, named the diffraction matrix method (DMM), that can accurately predict the optical characteristics of periodically corrugated OLEDs while achieving calculation speed that is a few orders of magnitude faster. Our method decomposes the light emitted by a dipolar emitter into plane waves with different wavevectors and tracks the diffraction behavior of waves using diffraction matrices. Calculated optical parameters show a quantitative agreement with those predicted by finite-difference time-domain (FDTD) method. Furthermore, the developed method possesses a unique advantage over the conventional approaches that it naturally evaluates the wavevector-dependent power dissipation of a dipole and is thus capable of identifying the loss channels inside OLEDs in a quantitative manner. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

关键词： computation methods Diffraction theory Finite element method Light extraction Matrix methods Purcell effect

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Towards self-calibrated lens metrology by differentiable refractive deflectometry

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OPTICS EXPRESS 2021年第19期29卷 30284-30295页

作者： Wang, Congli Chen, Ni Heidrich, Wolfgang King Abdullah Univ Sci & Technol Visual Comp Ctr Thuwal 239556900 Saudi Arabia

Deflectometry, as a non-contact, fully optical metrology method, is difficult to apply to refractive elements due to multi-surface entanglement and precise pose alignment. Here, we present a computational self-calibration approach to measure parametric lenses using dual-camera refractive deflectometry, achieved by an accurate, differentiable, and efficient ray tracing framework for modeling the metrology setup, based on which damped least squares is utilized to estimate unknown lens shape and pose parameters. We successfully demonstrate both synthetic and experimental results on singlet lens surface curvature and asphere-freeform metrology in a transmissive setting. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： computation methods Phase measurement Phase retrieval Ray tracing Refractive index Surface measurements

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Compound resonance-induced coupling effects in composite plasmonic metamaterials

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OPTICS EXPRESS 2012年第28期20卷 29447-29456页

作者： Farhang, Arash Ramakrishna, S. Anantha Martin, Olivier J. F. Swiss Fed Inst Technol Lausanne EPFL STI NAM Nanophoton & Metrol Lab CH-1015 Lausanne Switzerland Indian Inst Technol Dept Phys Metamat & Plasmon Lab Kanpur 208016 Uttar Pradesh India

We study a compound plasmonic system composed of a periodic Au grating array placed close to a thin Au film. The study is not limited to normal incidence and dispersion diagrams are computed for a broad variety of parameters. In addition to identifying localized and propagating modes and the coupling/hybridization interactions between them, we go further and identify modes of compound nature, i.e. those exhibiting both localized and propagating characteristics, and discuss which plasmon modes can exhibit such a behavior in the system at hand and how structural parameters play a central part in the spectral response of such modes. (C)2012 Optical Society of America

关键词： Composite materials computation methods Electric fields Localized surface plasmon resonance Surface plasmon resonance Thin films

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