Color optimization of a full-color holographic stereogram printing system using a single SLM based on iterative exposure control

Author(s):

Khuderchuluun, Anar; Dashdavaa, Erkhembaatar; Rupali, Shindae; Kwon, Ki-Chul; Kang, Hoonjong; Lee, Kwon-Yeon & Kim, Nam

Abstract:

“In this paper, color optimization of a full-color holographic stereogram printing system using a single SLM based on iterative exposure is proposed. First, an array of sub-holograms (hogels) is generated effectively within fast computergenerated integral imaging, and fully analyzed phase-modulation for red, green, and blue (RGB) channels of hogel. Then, the generated hogels are recorded into holographic material sequentially where SLM displays the R, G, and B channels of a single hogel via effectual exposure under synchronized control with three electrical shutters for RGB laser illumination to obtain verified color optimization. Numerical simulation and optical reconstructions are implemented.”

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Publication: Proc. SPIE
Issue/Year: Proc. SPIE 12445, Practical Holography XXXVII: Displays, Materials, and Applications, 124450A (8 March 2023)
DOI: 10.1117/12.2651038

Highly transparent wave front printed volume holograms realized by amplitude-modulated incoherent pre-illumination

Author(s):

Wilm, Tobias; Wieland, Max; Fiess, Reinhold & Stork, Wilhelm

Abstract:

“We present highly transparent, wave front printed volume holographic optical elements (vHOEs), realized with a new recording method based on the pre-illumination of incoherent light patterns. The introduced amplitudemodulated pattern illuminates a distinct area on the unexposed, photopolymer-based holographic recording material prior to the hologram recording sequence. The incoherent pre-illumination scheme enables a precise tuning of the material’s local photosensitivity without the formation of a holographic volume diraction grating. As a consequence, the pre-illumination exposure signicantly suppresses the formation of transparency diminishing structures in the material that are formed concurrently with the volume diraction grating during the hologram recording sequence. The pre-illumination component is integrated in an extended immersion-based wave front printing setup, which realizes vHOEs by sequentially recording single holographic elements in an array-like structure. A wide range of dierent recording congurations is enabled by our recording setup due to independent modulation of both wave fronts and the possibility to realize large o-axis recording angles. We introduce two hologram characterization methods, based on a diraction eciency and a slanted-edge method analysis, which are used to evaluate the implemented pre-illumination method and demonstrate signicant improvements to the see-through quality of the presented wave front recorded vHOEs.”

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Publication: Proc. SPIE 12445
Issue/Year: Proc. SPIE 12445, Practical Holography XXXVII: Displays, Materials, and Applications, 124450S, 2023
DOI: 10.1117/12.2647361

Objective method for visual performance prediction

Author(s):

Torres-Sepúlveda, Walter; lveda; Mira-Agudelo, Alejandro; Barrera-Ramirez, John Fredy & Kolodziejczyk, Andrzej

Abstract:

“We propose, implement, and validate a new objective method for predicting the trends of visual acuity through-focus curves provided by specific optical elements. The proposed method utilized imaging of sinusoidal gratings provided by the optical elements and the definition of acuity. A custom-made monocular visual simulator equipped with active optics was used to implement the objective method and to validate it via subjective measurements. Visual acuity measurements were obtained monocularly from a set of six subjects with paralyzed accommodation for a naked eye and then that eye compensated by four multifocal optical elements. The objective methodology successfully predicts the trends of the visual acuity through-focus curve for all considered cases. The Pearson correlation coefficient was 0.878 for all tested optical elements, which agrees with results obtained by similar works. The proposed method constitutes an easy and direct alternative technique for the objective testing of optical elements for ophthalmic and optometric applications, which can be implemented before invasive, demanding, or costly procedures on real subjects.”

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Publication: Journal of the Optical Society of America A
Issue/Year: Journal of the Optical Society of America A, Volume 40; Number 4; Pages C138; 2023
DOI: 10.1364/josaa.478022

Simulated LCSLM with Inducible Diffractive Theory to Display Super-Gaussian Arrays Applying the Transport-of-Intensity Equation

Author(s):

Arriaga-Hernandez, Jesus; Cuevas-Otahola, Bolivia; Oliveros-Oliveros, Jacobo; Morin-Castillo, Maria; Martinez-Laguna, Ygnacio & Cedillo-Ramirez, Lilia

Abstract:

“We simulate a liquid crystal spatial light modulator (LCSLM), previously validated by Fraunhofer diffraction to observe super-Gaussian periodic profiles and analyze the wavefront of optical surfaces applying the transport-of-intensity equation (TIE). The LCSLM represents an alternative to the Ronchi Rulings, allowing to avoid all the related issues regarding diffractive and refractive properties, and noise. To this aim, we developed and numerically simulated a LCSLM resembling a fractal from a generating base. Such a base is constituted by an active square (values equal to one) and surrounded by eight switched-off pixels (zero-valued). We replicate the base in order to form 1 ×N-pixels and the successive rows to build the 1024×1024 LCSLM of active pixels. We visually test the LCSLM with calibration images as a diffractive object that is mathematically inducible, using mathematical induction over the N×N-shape (1×1, 2×2, 3×3, …, n×n pixels for the generalization). Finally, we experimentally generate periodic super-Gaussian profiles to be visualized in the LCSLM (transmission SLM, 1024×768-pixels LC 2012 Translucent SLM), modifying the TIE as an optical test in order to analyze the optical elements by comparing the results with ZYGO/APEX.”

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Publication: Photonics
Issue/Year: Photonics, Volume 10; Number 1; Pages 39; 2022
DOI: 10.3390/photonics10010039

Parametric characterization of ground surfaces with laser speckles

Author(s):

León Schweickhardt, Andreas Tausendfreund, Dirk Stöbener, and Andreas Fischer

Abstract:

“With well-known speckle measurement techniques, the root mean square height as well as the autocorrelation length of isotropic surfaces can be determined quickly and over a large area of interest. Beyond that, the present article studies the speckle-based measurement of anisotropic surfaces. For this purpose, a measurement setup and evaluation algorithm are presented that enable the characterization of unidirectionally anisotropic surfaces machined by grinding. As a result, four measurands are obtained from one speckle image: the machining direction, the autocorrelation length perpendicular to the machining direction, as well as two root mean square roughness parameters parallel and perpendicular to the machining direction. The first two measurands are obtained from a two-dimensional fast Fourier transform of the diffraction pattern resulting from the unidirectional tool marks and the latter two by a bidirectional evaluation of the speckle contrast. In addition to measurements on physical reference samples, a spatial light modulator is used to create a large number of surface topographies with known model parameters in order to quantify the measurement uncertainty.”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 30; Number 8; Pages 12615; 2022
DOI: 10.1364/oe.454741

Adaptive Detection of Wave Aberrations Based on the Multichannel Filter

Author(s):

Khorin, Pavel A.; Porfirev, Alexey P. & Khonina, Svetlana N.

Abstract:

“An adaptive method for determining the type and magnitude of aberration in a wide range is proposed on the basis of an optical processing of the analyzed wavefront using a multichannel filter matched to the adjustable Zernike phase functions. The approach is based on an adaptive (or step-by-step) compensation of wavefront aberrations based on a dynamically tunable multichannel filter implemented on a spatial light modulator. For adaptive filter adjustment, a set of criteria is proposed that takes into account not only the magnitude of the correlation peak, but also the maximum intensity, compactness, and orientation of the distribution in each diffraction order. The experimental results have shown the efficiency of the proposed approach for detecting wavefront aberrations in a wide range (from 0.1 λ to λ).”

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Publication: Photonics
Issue/Year: Photonics, Volume 9; Number 3; Pages 204; 2022
DOI: 10.3390/photonics9030204

Singularities splitting phenomenon for the superposition of hybrid orders structured lights and the corresponding interference discrimination method

Author(s):

Mao, Baiwei; Liu, Yange; Chang, Wenzhe; Chen, Liang; Feng, Mao; Guo, Huiyi; He, Jiangyong & Wang, Zhi

Abstract:

“It is the basic characteristic of pure vortex light that there is a phase singularity at the origin. Such a singularity may be multiple degenerate, which determines the order of vortex light. Singularities splitting phenomenon means that singularities no longer concentrate at the origin but distribute around the space, usually occurring in impure vortex light. In this paper, we demonstrate the singularities splitting phenomenon and propose an analysis method, based on which one may rapidly estimate the modal components of impure vortex light. As two common singularity discrimination methods, the spiral and fork wire interference patterns are compared in distinguishing splitting singularities. The most widely used spiral interference pattern is revealed to be the worst form because of the low resolution. Instead, the fork wire interference pattern is with higher and easily adjusted resolution. 1‰ impurity is still able to be distinguished through fork wire interference patterns in the experiment.”

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Publication: Nanophotonics
Issue/Year: Nanophotonics, Volume 0; Number 0; 2022
DOI: 10.1515/nanoph-2021-0814

Large depth-of-field fluorescence microscopy based on deep learning supported by Fresnel incoherent correlation holography

Author(s):

Wu, Peng; Zhang, Dejie; Yuan, Jing; Zeng, Shaoqun; Gong, Hui; Luo, Qingming & Yang, Xiaoquan

Abstract:

“Fluorescence microscopy plays an irreplaceable role in biomedicine. However, limited depth of field (DoF) of fluorescence microscopy is always an obstacle of image quality, especially when the sample is with an uneven surface or distributed in different depths. In this manuscript, we combine deep learning with Fresnel incoherent correlation holography to describe a method to obtain significant large DoF fluorescence microscopy. Firstly, the hologram is restored by the Auto-ASP method from out-of-focus to in-focus in double-spherical wave Fresnel incoherent correlation holography. Then, we use a generative adversarial network to eliminate the artifacts introduced by Auto-ASP and output the high-quality image as a result. We use fluorescent beads, USAF target and mouse brain as samples to demonstrate the large DoF of more than 400µm, which is 13 times better than that of traditional wide-field microscopy. Moreover, our method is with a simple structure, which can be easily combined with many existing fluorescence microscopic imaging technology”

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Publication: Optics Express
Issue/Year: Optics Express, Volume 30; Number 4; Pages 5177; 2022
DOI: 10.1364/oe.451409

Scalability of all-optical neural networks based on spatial light modulators

Author(s):

Ying Zuo, Zhao Yujun, You-Chiuan Chen, Shengwang Du & Liu, Junwei

Abstract:

“Optical implementation of artificial neural networks has been attracting great attention due to its potential in parallel computation at speed of light. Although all-optical deep neural networks (AODNNs) with a few neurons have been experimentally demonstrated with acceptable errors re- cently, the feasibility of large scale AODNNs remains unknown because error might accumulate inevitably with increasing number of neurons and connections. Here, we demonstrate a scalable AODNN with programmable linear operations and tunable nonlinear activation functions. We ver- ify its scalability by measuring and analyzing errors propagating from a single neuron to the entire network. The feasibility of AODNNs is further confirmed by recognizing handwritten digits and fashions respectively.”

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Publication: Physical Review Applied
Issue/Year: Physical Review Applied, 2021
DOI: https://doi.org/10.1103/PhysRevApplied.15.054034

Discretized continuous quantum-mechanical observables that are neither continuous nor discrete

Author(s):

Thais L. Silva, Łukasz Rudnicki, Daniel S. Tasca, and Stephen P. Walborn

Abstract:

“Most of the fundamental characteristics of quantum mechanics, such as nonlocality and contextuality, are manifest in discrete, finite-dimensional systems. However, many quantum information tasks that exploit these properties cannot be directly adapted to continuous variable systems. To access these quantum features, continuous quantum variables can be made discrete by binning together their different values, resulting in observables with a finite number, d, of outcomes. While direct measurement indeed confirms their manifestly discrete character, here we employ a salient feature of quantum physics known as mutual unbiasedness to show that such coarse-grained observables are in a sense neither continuous nor discrete. Depending on d, the observables can reproduce either the discrete or the continuous behavior, or neither. To illustrate these results, we present an example for the construction of such measurements and employ it in an optical experiment confirming the existence of four mutually unbiased measurements with d=3 outcomes in a continuous variable system, surpassing the number of mutually unbiased continuous variable observables.”

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Publication: Physical Review Research
Issue/Year: Physical Review Research, Volume 4; Number 1; Pages 013060; 2022
DOI: 10.1103/physrevresearch.4.013060
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