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A systematic analysis for the quantitative comparison of phase retrieval methods based on alternating projections

OPTICS AND LASERS IN ENGINEERING 2018年第Jul.期106卷 24-31页

作者： Veiras, Francisco E. Bianchetti, Arturo Etchepareborda, Pablo Vadnjal, Ana L. Federico, Alejandro Univ Buenos Aires Fac Ingn Dept Fis GLOmAe CONICET C1063ACV Buenos Aires DF Argentina Inst Nacl Tecnol Ind Elect & Informat POB B1650WABB1650KNA San Martin Argentina Consejo Nacl Invest Cient & Tecn Elect & Informat Inst Nacl Tecnol Ind POB B1650WAB BI650KNA San Martin Argentina

We present a numerical and experimental scheme for the systematic analysis and comparison of phase retrieval techniques based on alternating projection numerical methods. This comparison allows us to evaluate the most common and recently introduced phase retrieval methods. The proposed scheme gives a quantitative comparison that helps to elucidate the differences between them and develop proper technical implementations of phase retrieval. The comparison is made by means of a numerical and experimental scheme that allows us to evaluate phase retrieval experiments. In this work, the drawbacks of using arbitrary random initial seeds to support the phase retrieval numerical algorithms are also analyzed and discussed. Moreover, we show the convenience of using a rough object phase estimation, which is obtained by means of a simple holographic technique, as the initial seed. This seed dramatically reduces the computational load of the algorithms by decreasing the successive iterations from hundreds to less than twenty. The experimental object under study is a random phase object within a micro-channel. As a proof of concept, this micro-channel combined with a millimeter size semicircular hole, which provides a reference wave, conforms a primitive sensor. The performance of the algorithms is not only measured by the usual convergence error, but also by means of a quality index that requires a direct comparison against the generally unknown original phase object. Thus, in order to evaluate the experimental performance of the phase retrieval techniques, we implement an interferometric optical setup that allows us to compare the results obtained by both techniques. The experiment proposed is a valuable tool for quantitative experimental evaluation of phase retrieval techniques in the optical domain. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Phase retrieval Metrological instrumentation computation methods

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Efficient marching solver for a class of three-dimensional optical waveguides

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OPTICS EXPRESS 2018年第12期26卷 15110-15123页

作者： Zhu, Jianxin Yang, Hao Jinan Univ Dept Math Guangzhou 510632 Guangdong Peoples R China Zhejiang Univ City Coll Sch Comp & Comp Sci Hangzhou 310015 Zhejiang Peoples R China

An efficient marching method of the wave propagation computation in the three-dimensional (3D) rectangular box is developed by solving the scalar Helmholtz equation with the weakly range-dependent refractive-index or wavenumber profile. The method is based on the application of the one-way formulation accompanied by a truncated technique that allows for the reduction of the number of eigenmodes and for quickly achieving reliable numerical results. The merits of the high accuracy and fast computation with a larger range step are shown to solve the equation. This treatment can be also applied to other complicated 3D waveguides. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.

关键词： computation methods Fourier transforms Inhomogeneous optical media Numerical simulation Refractive index Wave propagation

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Accelerated and high-quality Fourier ptychographic method using a double truncated Wirtinger criteria

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OPTICS EXPRESS 2018年第20期26卷 26556-26565页

作者： Liu, Jian Li, Yong Wang, Weibo Tan, Jiubin Liu, Chenguang Harbin Inst Technol Inst Ultraprecis Optoelect Instrument Engn Harbin 150001 Heilongjiang Peoples R China Harbin Inst Technol Space Environm Simulat Res Infrastruct Harbin 150001 Heilongjiang Peoples R China

Fourier ptychographic microscopy (FPM) is a recently developed computational microscopy technique for wide-field-of-view and super-resolution complex imaging. Wirtinger-flow-based methods can effectively suppress noise and reduce data acquisition time, but they are time-consuming during the phase reconstruction. In this paper, we present a Wirtinger-flow-based reconstruction method for FPM, which combines the Poisson maximum likelihood objective function, improved truncated Wirtinger criteria, and improved adaptive momentum method. Both the simulation and experimental results demonstrate that the proposed method runs faster and the reconstruction quality is similar to or better than other state-of-the-art Wirtinger-flow-based methods. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Aperture synthesis computation methods Fourier transforms Optical microscopy Phase retrieval Superresolution

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Decision feedback equalizer for holographic data storage

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APPLIED OPTICS 2018年第15期57卷 4056-4066页

作者： Kim, Kyuhwan Kim, Seung Hun Koo, Gyogwon Seo, Min Seok Kim, Sang Woo Pohang Univ Sci & Technol Dept Elect Engn 77 Cheongam Ro Pohang South Korea

Holographic data storage (HDS) has attracted much attention as a next-generation storage medium. Because HDS suffers from two-dimensional (2D) inter-symbol interference (IST), the partial-response maximum likelihood (PRML) method has been studied to reduce 2D IST. However, the PRML method has various drawbacks. To solve the problems, we propose a modified decision feedback equalizer (DFE) for HDS. To prevent the error propagation problem, which is a typical problem in DFEs, we also propose a reliability factor for HDS. Various simulations were executed to analyze the performance of the proposed methods. The proposed methods showed fast processing speed after training, superior bit error rate performance, and consistency. (C) 2018 Optical Society of America

关键词： computation methods Holographic memory Holographic techniques Laser beams Phase modulation Spatial light modulators

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Non-paraxial idealized polarizer model

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OPTICS EXPRESS 2018年第8期26卷 9840-9849页

作者： Zhang, Site Partanen, Henri Hellmann, Christian Wyrowski, Frank Friedrich Schiller Univ Jena Inst Appl Phys Appl Computat Opt Grp Albert Einstein Str 15 D-07743 Jena Germany LightTrans Int UG Kahlaische Str 4 D-07745 Jena Germany Univ Eastern Finland Yliopistokatu 2 FI-80100 Joensuu Finland Wyrowski Photon UG Kahlaische Str 4 D-07745 Jena Germany

An idealized polarizer model that works without the structural and material information is derived in the spatial frequency domain. The non-paraxial property is fully included and the result takes a simple analytical form, which provides a straight-forward explanation for the crosstalk between field components in non-paraxial cases. The polarizer model, in a 2 X 2-matrix form, can be conveniently used in cooperation with other computational optics methods. Two examples in correspondence with related works are presented to verify our polarizer model. (C) 2018 Optical Society of America

关键词： computation methods Fourier transforms Matrix methods Optical components Polarizers Spatial frequency

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Hybrid method of plane-wave and cylindrical-wave expansions for distributed Bragg-reflector pillars: formalism and its application to topological photonics

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS 2018年第11期35卷 2642-2653页

作者： Ochiai, Tetsuyuki NIMS Res Ctr Funct Mat Tsukuba Ibaraki 3050044 Japan

A hybrid computational method of plane-wave and cylindrical-wave expansions for distributed Bragg-reflector (DBR) pillars is proposed. The plane-wave expansion is employed to represent the one-dimensional periodic structure of the DBR. The cylindrical-wave expansion is employed to describe the scattering by circular pillars with the DBR structure inside. This formalism enables us to calculate the radiation fields, t matrices, scattering cross sections, photonic band structures, and quality factors of the DBR pillars. Furthermore, optical properties of arrayed DBR pillars are also investigated with the aid of the multiple-scattering method. Using this formalism, we demonstrate explicitly that high Q photonic band modes including the so-called bound states in continuum are obtained both in isolated and arrayed DBR pillars. We also present a novel formation of gapless Dirac-cone surface states in a three-dimensional photonic crystal composed of a two-dimensional periodic arrangement of core-shell DBR pillars. (c) 2018 Optical Society of America.

关键词： Channeled waveguides computation methods Fano resonance Mie theory Quantum optics Refractive index

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computational analysis of dispersive and nonlinear 2D materials by using a GS-FDTD method

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS 2018年第11期35卷 2754-2763页

作者： You, Jian Wei Threlfall, Edward Gallagher, Dominic F. G. Panoiu, Nicolae C. UCL Dept Elect & Elect Engn London WC1E 7JE England Photon Design Ltd 34 Leopold St Oxford OX4 1TW England

In this paper, we propose a novel numerical method for modeling nanostructures containing dispersive and non-linear two-dimensional (2D) materials, by incorporating a nonlinear generalized source (GS) into the finite-difference time-domain (FDTD) method. Starting from the expressions of nonlinear currents characterizing non-linear processes in 2D materials, such as second- and third-harmonic generation, we prove that the non-linear response of such nanostructures can be rigorously determined using two linear simulations. In the first simulation, one computes the linear response of the system upon its excitation by a pulsed incoming wave, whereas in the second one the system is excited by a nonlinear GS, which is determined by the linear near-field calculated in the first linear simulation. This new method is particularly suitable for the analysis of dispersive and nonlinear 2D materials, such as graphene and transition-metal dichalcogenides, chiefly because, unlike the case of most alternative approaches, it does not require the thickness of the 2D material. To investigate the accuracy of the proposed GS-FDTD method and illustrate its versatility, the linear and nonlinear responses of graphene gratings have been calculated and compared to results obtained using alternative methods. Importantly, the proposed GS-FDTD can be extended to three-dimensional bulk nonlinearities, rendering it a powerful tool for the design and analysis of more complicated nanodevices. (c) 2018 Optical Society of America

关键词： computation methods Nonlinear effects Nonlinear optical devices Nonlinear photonic crystals Optical materials Photonic crystal cavities

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Experimental demonstration of a directionally-unbiased linear-optical multiport

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OPTICS EXPRESS 2018年第21期26卷 27201-27211页

作者： Osawa, Shuto Simon, David S. Sergienko, Alexander, V Boston Univ Dept Elect & Comp Engn 8 St Marys St Boston MA 02215 USA Stonehill Coll Dept Phys & Astron 320 Washington St Easton MA 02357 USA Boston Univ Dept Phys 590 Commonwealth Ave Boston MA 02215 USA Boston Univ Photon Ctr 8 St Marys St Boston MA 02215 USA

All existing optical quantum walk approaches are based on the use of beamsplitters and multiple paths to explore the multitude of unitary transformations of quantum amplitudes in a Hilbert space. The beamsplitter is naturally a directionally biased device: the photon cannot travel in the reverse direction. This causes rapid increases in the optical hardware resources required for complex quantum walk applications, since the number of options for the walking particle grows with each step. Here we present the experimental demonstration of a directionally-unbiased linear-optical multiport, which allows reversibility of the photon direction. An amplitude-controllable probability distribution matrix for a unitary three-edge vertex is reconstructed with only linear-optical devices. Such directionally-unbiased multiports allow direct execution of quantum walks over a multitude of complex graphs and in tensor networks. This approach would enable simulation of complex Hamiltonians of physical systems and quantum walk applications in a more efficient and compact setup, substantially reducing the required hardware resources. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Beam splitters computation methods Interferometry Light beams Quantum information processing Single photon avalanche diodes

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Extended photoacoustic transport model for characterization of red blood cell morphology in microchannel flow

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BIOMEDICAL OPTICS EXPRESS 2018年第6期9卷 2785-2809页

作者： Uluc, Nasire Unlu, Mehmet Burcin Gulsen, Gultekin Erkol, Hakan Bogazici Univ Dept Phys TR-34342 Istanbul Turkey Hokkaido Univ Global Inst Collaborat Res & Educ GI CoRE Global Stn Quantum Med Sci & Engn Sapporo Hokkaido 0608648 Japan Stanford Univ Sch Med Dept Radiat Oncol Stanford CA 94305 USA Univ Calif Irvine Dept Radiol Sci Irvine CA 92717 USA

The dynamic response behavior of red blood cells holds the key to understanding red blood cell related diseases. In this regard, an understanding of the physiological functions of erythrocytes is significant before focusing on red blood cell aggregation in the microcirculatory system. In this work, we present a theoretical model for a photoacoustic signal that occurs when deformed red blood cells pass through a microfluidic channel. Using a Green's function approach, the photoacoustic pressure wave is obtained analytically by solving a combined Navier-Stokes and photoacoustic equation system. The photoacoustic wave expression includes determinant parameters for the cell deformability such as plasma viscosity, density, and red blood cell aggregation, as well as involving laser parameters such as beamwidth, pulse duration, and repetition rate. The effects of aggregation on blood rheology are also investigated. The results presented by this study show good agreements with the experimental ones in the literature. The comprehensive analytical solution of the extended photoacoustic transport model including a modified Morse type potential function sheds light on the dynamics of aggregate formation and demonstrates that the profile of a photoacoustic pressure wave has the potential for detecting and characterizing red blood cell aggregation. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： computation methods Laser beams Magnetic fields Multiple scattering Power spectral density Temporal resolution

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Improving mesoscopic fluorescence molecular tomography via preconditioning and regularization

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BIOMEDICAL OPTICS EXPRESS 2018年第6期9卷 2765-2778页

作者： Yang, Fugang Yao, Ruoyang Ozturk, Mehmet Faulkner, Denzel Qu, Qinglan Intes, Xavier Shandong Inst Business & Technol Sch Informat & Elect Engn Yantai 264005 Peoples R China Rensselaer Polytech Inst Dept Biomed Engn 110 8th St Troy NY 12180 USA Qingdao Univ Affiliated Hosp Yantai Yuhuangding Hosp Dept Reprod Med Yantai 264000 Peoples R China

Mesoscopic fluorescence molecular tomography (MFMT) is a novel imaging technique capable of obtaining 3-D distribution of molecular probes inside biological tissues at depths of a few millimeters with a resolution up to similar to 100 mu m. However, the ill-conditioned nature of the MFMT inverse problem severely deteriorates its reconstruction performances. Furthermore, dense spatial sampling and fine discretization of the imaging volume required for high resolution reconstructions make the sensitivity matrix (Jacobian) highly correlated, which prevents even advanced algorithms from achieving optimal solutions. In this work, we propose two computational methods to respectively increase the incoherence of the sensitivity matrix and improve the convergence rate of the inverse solver. We first apply a compressed sensing (CS) based preconditioner on either the whole sensitivity matrix or sub sensitivity matrices to reduce the coherence between columns of the sensitivity matrix. Then we employed a regularization method based on the weight iterative improvement method (WIIM) to mitigate the ill-condition of the sensitivity matrix and to drive the iterative optimization process towards convergence at a faster rate. We performed numerical simulations and phantom experiments to validate the effectiveness of the proposed strategies. In both in silico and in vitro cases, we were able to improve the quality of MFMT reconstructions significantly. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： computation methods Diffuse optical tomography Inverse problems Molecular imaging Molecular probes Numerical simulation

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