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Accepted papers to appear in an upcoming issue

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Influence of naturalness of chroma and lightnesscontrast modulation on colorfulness adaptation innatural images

Taishi Masumitsu and Yoko Mizokami

DOI: 10.1364/JOSAA.382414 Received 08 Nov 2019; Accepted 26 Mar 2020; Posted 27 Mar 2020  View: PDF

Abstract: We investigated as to whether the naturalness of images modulated by a combination of chroma and lightnesscontrast affects the colorfulness perception. Four types of modulated images with different combinations ofchroma and lightness contrast were used as adaptation stimuli. After adapting to one of the adaptation stimuligroups, observers judged the colorfulness of test images that were also modulated by the different combinations ofchroma and lightness contrast. Our results showed that the combination of chroma and lightness contrastmodulation affected the strength of colorfulness adaptation. The results also indicated that when adapting toimages that exhibited high naturalness, the effect of colorfulness adaptation was strong. It was suggested that thenaturalness of chroma and lightness combination is an important factor for colorfulness adaptation.

Propagation of fully and partially coherent Flat-toppedmulti Gaussian beams through axicons

Fatima Thabit, Abdu Alkelly, and Mohammed Shukri

DOI: 10.1364/JOSAA.386820 Received 14 Jan 2020; Accepted 23 Mar 2020; Posted 23 Mar 2020  View: PDF

Abstract: Theoretically, we have investigated the propagation of fully and partially coherent Flat-topped multi-GaussianBeams (FMGB) through classical and logarithmic axicons. The method of stationary phase applied to the Fresneldiffraction integral for intensity distribution has led to an applicable relations. The influence of axicon base angle,beam width, beam flatness and coherence length with intensity distribution were studied. A number of results havebeen analyzed and discussed revealing some important conclusions. During this investigation a specific interest hasbeen given toward producing uniform intensity and long focal depth.

Scintillation Averaging and Fade Statistics

Scot Shaw

DOI: 10.1364/JOSAA.388567 Received 20 Jan 2020; Accepted 23 Mar 2020; Posted 23 Mar 2020  View: PDF

Abstract: This work develops expressions for the variance and power spectral density (PSD) of atmosphericallyinduced amplitude fluctuations of a propagating beam of light, also known as scintillation. This extendsa recently published analytic approach for atmospheric propagation studies, previously applied to thephase properties of a propagating beam. In addition to laying out the general principles for manipulating log-amplitude expressions, this work develops novel expressions for scintillation under aperture,path, wavelength, and temporal averaging, first separately and then as a unified expression. The PSDexpression is then used to find several statistics of fades of given depth and duration, including fadeprobability, rate, and average duration. Results are shown throughout to agree with existing literatureand wave-optics simulations.

Optical-vortex diagnostics via Fraunhofer slitdiffraction with controllable wavefront curvature

Aleksandr Bekshaev, Lidiya Mikhaylovskaya, Satyajeet Patil, Vijay Kumar, and Ravindra Singh

DOI: 10.1364/JOSAA.388926 Received 23 Jan 2020; Accepted 23 Mar 2020; Posted 24 Mar 2020  View: PDF

Abstract: Far-field slit-diffraction of circular optical-vortex (OV) beams is efficient for measurement of the topological charge (TC)magnitude but does not reveal its sign. We show that this is because in the common diffraction schemes the diffractionplane coincides with the incident OV waist plane. Based on the examples of Laguerre-Gaussian incident beamscontaining a spherical wavefront component, we demonstrate that the far-field diffracted beam profile possesses anasymmetry depending on the incident wavefront curvature and the TC sign. This finding enables simple and efficientways for the simultaneous diagnostics of the TC magnitude and sign, which can be useful in many OV applications,including the OV-assisted metrology and information processing.

Testing scalar diffraction theory: Gaussian beamon a slit

Luka Zurak, Velimir Labinac, Natasa Erceg, Ivica Aviani, Marko Jusup, and Marin Karuza

DOI: 10.1364/JOSAA.388703 Received 21 Jan 2020; Accepted 23 Mar 2020; Posted 24 Mar 2020  View: PDF

Abstract: We recorded diffraction patterns using commercially available slit and sensor over a wide range of experimental circumstances, including near- and far-field regimes and oblique incidence at large angles. Wethen compared the measured patterns with theoretical intensity curves calculated via the numerical integration of formulas derived within the framework of scalar diffraction theory. Experiment and theoryshow particularly good agreement when the first Rayleigh-Sommerfeld (R-S) formula is used. The Kirchhoff formula, though problematic in the context of mathematical consistency, agrees with the first R-Sformula even for large incidence angles, whereas the second R-S formula differs visibly. To obtain sucha good agreement, we replaced the assumption of an incident plane wave with that of a Gaussian beam,and implemented geometric corrections to account for slit imperfections. These results reveal how thescope of scalar diffraction theory can be extended with a small set of auxiliary assumptions.

Optimal Laguerre-Gaussian Modes for High-IntensityOptical Vortices

Andrew Longman and Robert Fedosejevs

DOI: 10.1364/JOSAA.389031 Received 07 Feb 2020; Accepted 23 Mar 2020; Posted 24 Mar 2020  View: PDF

Abstract: With increasing interest in using orbital angular momentum (OAM) modes in high-power laser systems,accurate mathematical descriptions of the high-intensity modes at focus are required for realistic modelling. In this work, we derive various high intensity orbital angular momentum focal spot intensitydistributions generated by Gaussian, super-Gaussian, and ideal flat-top beams common to high-powerlaser systems. These intensity distributions are then approximated using fitted Laguerre-Gaussian basisfunctions as a practical way for describing high-power OAM beams in theoretical and numerical models.

Band-rejection filter with high-extinction ratio usingprism-waveguide cascaded coupling system

Maowu Ran, Wenjuan Cai, Zhang Yingcong, XianPing Wang, Yanchao She, Cheng Yin, and Jian Wu

DOI: 10.1364/JOSAA.384704 Received 02 Dec 2019; Accepted 22 Mar 2020; Posted 23 Mar 2020  View: PDF

Abstract: A band-rejection filter is proposed based on a prism-waveguide cascaded coupling system, which is composed of anequilateral trapezium prism and a deposited multilayer structure. By properly adjusting the thickness of thecoupling layer and the light extinction coefficient of the guiding layer, the radiative and intrinsic dampingsmatching condition could be well satisfied, and then a series of reflectivity dips will appear in the reflectivitywavelength spectrum. Since the module of reflectivity is small than 1, thus the extinction ratio of the rejectedfrequency via the cascaded coupling system is twice as high as that of the single coupling technology. By narrowingthe guiding layer to a micrometer scale, the free spectral range is broad enough to cover the Raman spectrumscattered from the frequently-used sample. In addition, the numerically calculated results show that the light in thefree spectral range is mostly reflected with an insertion loss down to 0.45 dB. Compared to previously reportedband-rejection filters, it is relatively simple to manufacture our device, which possesses potential applications tohelp distinguish the Raman signal from the elastic scattering background.

Multispectral image fusion based pedestriandetection using a multilayer fused deconvolutionalsingle-shot detector

Yunfan Chen and hyunchul shin

DOI: 10.1364/JOSAA.386410 Received 20 Dec 2019; Accepted 22 Mar 2020; Posted 23 Mar 2020  View: PDF

Abstract: Recent research has demonstrated that effective fusion of multispectral images (visible and thermal images)enables robust pedestrian detection under various illumination conditions (e.g., daytime and nighttime). However,there are some open problems such as poor performance in small-sized pedestrian detection and highcomputational cost of multispectral information fusion. This paper proposes a multilayer fused deconvolutionalsingle-shot detector (MFDSSD) that contains a two-stream convolutional module (TCM) and a multilayer fuseddeconvolutional module (MFDM). The TCM is used to extract convolutional features from multispectral inputimages. Then, novel fusion blocks are incorporated into the MFDM to combine high-level features with richsemantic information and low-level features with detailed information, aiming at generating features with strongrepresentational power for small pedestrian instances. In addition, we fuse multispectral information at multipledeconvolutional layers in the MFDM via fusion blocks. This multilayer fusion strategy adaptively makes the mostuse of visible and thermal information. In addition, using fusion blocks for multilayer fusion can reduce the extracomputational cost and redundant parameters. Empirical experiments show that the proposed approach achieves81.82% average precision (AP) on a new small-sized multispectral pedestrian dataset. The proposed methodachieves the best performance on two well-known public multispectral datasets. For example, on the KAISTmultispectral pedestrian benchmark, our method achieves 97.36% AP and 20 fps detection speed, whichoutperforms the state-of-the-art published method by 6.82% in AP and is three times faster in detection speed.

Multi-mode communication through the turbulentatmosphere

Liliana Borcea, Josselin Garnier, and Knut Solna

DOI: 10.1364/JOSAA.384007 Received 22 Nov 2019; Accepted 18 Mar 2020; Posted 19 Mar 2020  View: PDF

Abstract: A central question in free-space optical communications is how to improve the transfer of informationbetween a transmitter and receiver. The capacity of the communication channel can be increased by multiplexing of independent modes using either: (1) the MIMO (Multiple-Input-Multiple-Output) approach,where the communication is done with modes obtained from the singular value decomposition of thetransfer matrix from the transmitter array to the receiver array, or (2) the OAM (Orbital Angular Momentum) approach, which uses vortex beams that carry angular momenta. In both cases, the number of usablemodes is limited by the finite aperture of the transmitter and receiver, and the effect of the turbulent atmosphere. The goal of this paper is twofold: First, we show that the MIMO and OAM multiplexingschemes are closely related. Specifically, in the case of circular apertures, the leading singular vectors ofthe transfer matrix which are useful for communication are essentially the same as the commonly usedLaguerre-Gauss vortex beams, provided these have a special radius that depends on the wavelength, thedistance from the transmitter to the receiver and the ratio of the radii of their apertures. Second, we characterize the effect of atmospheric turbulence on the communication modes using the phase screen methodput in the mathematical framework of beam propagation in random media.

Comparison of four techniques for turbulentphase screens simulation

Mikhail Charnotskii

DOI: 10.1364/JOSAA.385754 Received 12 Dec 2019; Accepted 18 Mar 2020; Posted 20 Mar 2020  View: PDF

Abstract: In the study, we introduce a new technique, Sparse spectrum with Uniform wavevectors (SU), for generation of phase screen samples. In a manner similar to the known SparseSpectrum (SS) technique, it uses trigonometric series with random discrete spectral support.However, in contrast to the SS technique, random wave vectors are uniformly distributed onindividual segments of the wave vector plane partition in the SU technique. We compare theaccuracy and computational effectiveness of the SU technique with the subharmonicscomplemented DFT technique, SS technique, and randomized DFT technique [J. Opt. Soc.Am. B 36, 3249 (2019)]. The SU and SS techniques generate unbiased samples and indicatesuperior computational effectiveness for 1 MP and larger screens.

Blues do not bring the blues: challenging conventional notions of color-emotion associations

Karen Schloss, Christoph Witzel, and Leslie Lai

DOI: 10.1364/JOSAA.383588 Received 18 Nov 2019; Accepted 15 Mar 2020; Posted 16 Mar 2020  View: PDF

Abstract: In popular culture and some scientific literature it is commonly held that yellow is happy and blue is sad, but the reason remains a mystery. There is confusion in the field about what "yellow" and "blue" refer to and this confusion prevents us from understanding the origins of color-emotion associations. In this study we disentangled the contribution of lightness, chroma, and hue in color-happiness associations. In Experiment 1 we assessed color-emotion associations for colors that were equated in lightness and chroma in CIEL*c*h* color space. In Experiment 2, we repeated Experiment 1, but also included colors that were perceptually matched for saturation. The results indicated that light high chroma colors were happy and dark low chroma colors were sad. Bluer colors were no sadder than yellower colors, and if anything bluer colors were happier than yellow colors when they were dark. These results can help guide efforts to understand the nature of color-emotion associations.

Visual losses in early-onset and late-onset Parkinson’s disease

Claudia Feitosa-Santana, Marcelo Costa, Henrique Ferraz, Luiz Augusto Andrade, Edson Amaro-Jr, Russell Hamer, Dora Ventura, and Ana Laura Moura

DOI: 10.1364/JOSAA.382042 Received 06 Nov 2019; Accepted 14 Mar 2020; Posted 16 Mar 2020  View: PDF

Abstract: Patients with Parkinson’s disease (PD) manifest losses in visual contrast sensitivity (CS). However, it is not known whether the losses are equivalent in both early-onset (EOPD) and late-onset (LOPD) patients. We evaluated spatiotemporal CS in EOPD and LOPD patients and in age-matched controls. Losses occurred in both patient groups, with more pronounced losses occurring in EOPD, consistent with the notion that non-motor symptoms are affected by age of symptom-onset. More studies of visual function in EOPD and LOPD patients are needed to better characterize the etiology of PD, perhaps permitting earlier diagnosis and/or improved treatment and management of the disease.

Designing laser beams carrying OAM for a highperformance underwater communication system

Svetlana Avramov-Zamurovic, Abbie Watnik, james lindle, and Kyle Judd

DOI: 10.1364/JOSAA.388370 Received 16 Jan 2020; Accepted 12 Mar 2020; Posted 16 Mar 2020  View: PDF

Abstract: We present a design methodology for creating a distinct laser beam set suitable for detection by usingonly the recorded intensity pattern. We consider four coherent Laguerre Gaussian (LG) beams carrying OrbitalAngular Momentum (OAM) to form the basis for optical communication. The complex electric fields of the beamsare superimposed to create 16 dissimilar intensity patterns. The presented beam set design method considers thebeam generation hardware limitations and aims to minimize the correlation among the messages and maximize theirintensity differences. After propagating the 16 messages through a water channel, we measured high correlation,intensity similarity, and R-squared values for the identical messages and low values for the different ones. Distinctclustering between the measurements for the matching messages and the rest, allows us to set a threshold in the gapamong the groupings and successfully classify the received images.

Propagation properties of partially coherent anomalous hollowbeams in quadratic-index media

Jin Gui, Lirong Bian, and Bin Tang

DOI: 10.1364/JOSAA.388566 Received 20 Jan 2020; Accepted 10 Mar 2020; Posted 11 Mar 2020  View: PDF

Abstract: Based on the generalized diffraction integral formula, analytical propagation expressions for a partially coherentanomalous hollow beam (AHB) propagating through a quadratic-index medium are derived. The distributions of intensityand Poynting vector for a partially coherent AHB through the quadratic-index medium are numerically and theoreticallystudied. It is found that the intensity and Poynting vector of the partially coherent AHB take on a periodical change. Theevolution properties of the partially coherent AHB in a quadratic-index medium are closely relevant to its transversecoherence width and the quadratic-index parameter of media.

Demonstrating a multi-primary high dynamicrange display system for vision experiments

Allie Hexley, Ali Yontem, Manuel Spitschan, Hannah Smithson, and Rafal Mantiuk

DOI: 10.1364/JOSAA.384022 Received 22 Nov 2019; Accepted 09 Mar 2020; Posted 09 Mar 2020  View: PDF

Abstract: We describe the design, construction, calibration, and characterization of a multiprimary high dynamic range (MPHDR) display system for use in vision research. The MPHDRdisplay is the first system to our knowledge to allow for spatially controllable, high dynamicrange stimulus generation using multiple primaries. We demonstrate the high luminance, highdynamic range, and wide colour gamut output of the MPHDR display. During characterization,the MPHDR display achieved a maximum luminance of 3200 cd/m2, a maximum contrast rangeof 3, 240, 000 : 1, and an expanded colour gamut tailored to dedicated vision research tasksthat spans beyond traditional sRGB displays. We discuss how the MPHDR display could beoptimized for psychophysical experiments with photoreceptor isolating stimuli achieved throughthe method of silent substitution. We present an example case of a range of metameric pairs ofmelanopsin isolating stimuli across different luminance levels, from an available melanopsincontrast of 117% at 75 cd/m2to a melanopsin contrast of % at 2000 cd/m2.

HELIX ROTATION: LUMINANCECONTRAST CONTROLS THE SHIFT FROMTWO-DIMENSIONAL TO THREEDIMENSIONAL PERCEPTION

Arthur G. Shapiro and Anthony LoPrete

DOI: 10.1364/JOSAA.382373 Received 12 Nov 2019; Accepted 06 Mar 2020; Posted 09 Mar 2020  View: PDF

Abstract: We present the Helix Rotation phenomenon, an array of moving dots that createsa conflict between two potential perceptions: a 3D Pulfrich-like horizontal rotation and alow-spatial-frequency up-down motion. We show that observers perceive up-down motionwhen the dots are equiluminant with the background and when the display is blurred; thatthe addition of sparse luminance information to equiluminant and blurred displays produces3D perception; and that the balance between the perception of 3D rotation and up-downmotion depends on the magnitude of the luminance contrast. The results are discussed interms of the luminance capture of equiluminant information.

Risley-prism-based Visual Tracing Method for RobotGuidance

Anhu Li, Qiao Li, Zhaojun Deng, and Yang Zhang

DOI: 10.1364/JOSAA.381445 Received 28 Oct 2019; Accepted 04 Mar 2020; Posted 05 Mar 2020  View: PDF

Abstract: A visual tracing model based on Risley prisms is proposed in this paper. Combined with the boresight adjustingtechnology and the visual detection technology, a new visual system is established. Placing Risley prisms in front ofthe camera, the field of view (FOV) of camera can be dynamically adjusted so that the imageable area of this camerais expanded greatly. Two real-time visual tracing strategies for dynamic targets are proposed, which effectivelyavoid the problems of target loss and tracking instability. The deviations between the reference trajectorygenerated by the manipulator and the actual trajectory detected by our visual system are measured. Experimentalresults show that the deviations are less than 1.5% in the 250mm motion space of the manipulator. It is verifiedthat the visual system can be used to guide robots with a high precision, which provides a potential method forrobot navigation.

Ultra-Broadband Metamaterial Absorber basedon Cross-Shaped TiN Resonators

Samira mehrabi, Mir Hamid Rezaei, and Abbas Zarifkar

DOI: 10.1364/JOSAA.389320 Received 29 Jan 2020; Accepted 02 Mar 2020; Posted 03 Mar 2020  View: PDF

Abstract: In this paper, a novel broadband plasmonic absorber based on cross-shapedtitanium nitride (TiN) resonators in the ultra-violet, visible, and near-infrared regions ispresented. The proposed perfect solar absorber consists of periodic arrays of cross-shapedTiN resonators located on a stack of SiO2/TiN layers. By using the finite difference timedomain (FDTD) method, the effect of variations of the thickness and radius of the ellipticalmetasurface resonators on the absorption is comprehensively investigated. The cross-shapedmetamaterial absorber exhibits an averaged absorption of 90%, ranging from 200 nm to 3000nm and shows over 90% absorption from 200 nm to 2500 nm. Furthermore, the proposedabsorber indicates absorption efficiency over 80% for an oblique incidence up to 50 degreesfor both TE- and TM-polarized light. These features make the proposed solar absorber usablein many solar-based applications, imaging, and thermal emitting.

Ghost polarimetry using Stokes correlations

Antti Hannonen, Bernhard Hoenders, Wolfgang Elsaesser, Ari Tapio Friberg, and Tero Setala

DOI: 10.1364/JOSAA.385851 Received 13 Dec 2019; Accepted 01 Mar 2020; Posted 02 Mar 2020  View: PDF

Abstract: We present a novel ghost polarimeter based on Stokes-parameter correlations and a spatially incoherent classical source with adjustable polarization state and Gaussian statistics. The setup enables to extract the four amplitudes and three phase differences related to the spectral 2x2 complex Jones matrix of any transmissive polarization-sensitive object. Our work extends the ghost-imaging methods from the traditional intensity-correlation measurements to the detection of polarization-state correlations.

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