scholarly journals Lensless Scheme for Measuring Laser Aberrations Based on Computer-Generated Holograms

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4310 ◽  
Author(s):  
George Krasin ◽  
Michael Kovalev ◽  
Nikita Stsepuro ◽  
Pavel Ruchka ◽  
Sergey Odinokov
Keyword(s):  
Numerical Simulation ◽  
Diffraction Efficiency ◽  
Holographic Method ◽  
Wavefront Sensors ◽  
Wavefront Aberrations ◽  
Implementation Scheme ◽  
Computer Generated Holograms

All of the existing holographic wavefront sensors are either bulky or have low accuracy of measuring wavefront aberrations. In this paper, we present an improvement of the holographic method of measuring wavefront aberrations using computer-generated Fourier holograms. The novelty of this work lies in the proposed approach to the synthesis of Fourier holograms, which are implemented using phase-only SLM. The main advantages of this method are the increased diffraction efficiency compared to the previously known methods, and the more compact implementation scheme due to the elimination of the conventional Fourier-lens. The efficiency of the proposed method was confirmed by numerical simulation and optical experiments.

Numerical Simulation of Plenoptic Camera Wavefront Sensors with Dynamic Modulation

2019 ◽  
Vol 39 (7) ◽  
pp. 0728008
Author(s):  
何宇龙 Yulong He ◽  
宁禹 Yu Ning ◽  
姜宗福 Zongfu Jiang ◽  
孙全 Quan Sun ◽  
张明 Ming Zhang
Keyword(s):  
Numerical Simulation ◽  
Wavefront Sensors ◽  
Dynamic Modulation ◽  
Plenoptic Camera

Exposure Schedule for Uniform Diffraction Efficiency of Partially-Overlapping Multiple Holograms in Dual Monomers Photopolymers

2013 ◽  
Vol 652-654 ◽  
pp. 638-641
Author(s):  
Wei Song ◽  
Shi Quan Tao ◽  
Da Yong Wang ◽  
Yun Xin Wang ◽  
Lisa Marx
Keyword(s):  
Numerical Simulation ◽  
Diffraction Efficiency ◽  
Optimization Problem ◽  
Holographic Storage ◽  
Schedule Model ◽  
Proposed Model

The exposure schedule model of uniform diffraction efficiency in single monomer photopolymer is extended to that in dual monomers with partially-overlapping multiplexing methods. The proposed model can be thought of solving an optimization problem. The exposure schedule for 51 holograms are calculated and verified by the numerical simulation. The result shows that the exposure schedule is effective to produce the uniform diffraction efficiency for the multiplexing holographic storage.

scholarly journals Optical Orbital Angular Momentum Demultiplexing and Channel Equalization by Using Equalizing Dammann Vortex Grating

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Mingyang Su ◽  
Junmin Liu ◽  
Yanliang He ◽  
Shuqing Chen ◽  
Ying Li
Keyword(s):  
Numerical Simulation ◽  
Angular Momentum ◽  
Light Intensity ◽  
Diffraction Efficiency ◽  
Orbital Angular Momentum ◽  
Bit Error Rate ◽  
Error Rate ◽  
Channel Equalization ◽  
Grating Structure

A novel equalizing Dammann vortex grating (EDVG) is proposed as orbital angular momentum (OAM) multiplexer to realize OAM signal demultiplexing and channel equalization. The EDVG is designed by suppressing odd diffraction orders and adjusting the grating structure. The light intensity of diffraction is subsequently distributed evenly in the diffraction orders, and the total diffraction efficiency can be improved from 53.22% to 82%. By using the EDVG, OAM demultiplexing and channel equalization can be realized. Numerical simulation shows that the bit error rate (BER) of each OAM channel can decrease to 10-4 when the bit SNR is 22 dB, and the intensity is distributed over the necessary order of diffraction evenly.

Constructing Chaotic Systems from a Class of Switching Systems

2018 ◽  
Vol 28 (02) ◽  
pp. 1850032 ◽  
Author(s):  
Yuping Zhang ◽  
Xinzhi Liu ◽  
Huaiyue Zhang ◽  
Chunhua Jia
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Continuous Time ◽  
Chaotic Systems ◽  
Switching Systems ◽  
Heteroclinic Loop ◽  
Time Switching ◽  
Loop Design ◽  
Implementation Scheme ◽  
Shilnikov Criterion

This paper aims to develop an approach for constructing chaotic systems from a class of linear continuous-time switching systems. First, the Shilnikov criterion is analyzed and extended to the switching systems. Then some kinds of “swing planes” are provided via a heteroclinic loop design, which act as switching planes to chaotify the systems. Furthermore, a numerical example is presented to validate the proposed principle and implementation scheme. The theoretical analysis and numerical simulation have demonstrated the feasibility and effectiveness of the developed techniques.

Effects of tear film dynamics on quality of vision

2018 ◽  
Vol 102 (12) ◽  
pp. 1615-1620 ◽  
Author(s):  
Shizuka Koh ◽  
Cynthia I Tung ◽  
Yasushi Inoue ◽  
Vishal Jhanji
Keyword(s):  
Dry Eye ◽  
Current Knowledge ◽  
Tear Film ◽  
Optical Quality ◽  
Eye Drops ◽  
Wavefront Sensors ◽  
Wavefront Aberrations ◽  
Quality Of Vision ◽  
Definition Of

The precorneal tear film is maintained by blinking and exhibits different phases in the tear cycle. The tear film serves as the most anterior surface of the eye and plays an important role as a first refractive component of the eye. Alterations in tear film dynamics may cause both vision-related and ocular surface-related symptoms. Although the optical quality associated with the tear film dynamics previously received little attention, objective measurements of optical quality using wavefront sensors have enabled us to quantify optical aberrations induced by the tear film. This has provided an objective method for assessing reduced optical quality in dry eye; thus, visual disturbances were included in the definition of dry eye disease in the 2007 Dry Eye Workshop report. In addition, sequential measurements of wavefront aberrations have provided us with valuable insights into the dynamic optical changes associated with tear film dynamics. This review will focus on the current knowledge of the mechanisms of wavefront variations that are caused by different aspects of tear film dynamics: specifically, quality, quantity and properties of the tear film, demonstrating the respective effects of dry eye, epiphora and instillation of eye drops on the quality of vision.

scholarly journals Optical detection of values of separate aberrations using a multi-channel filter matched with phase Zernike functions

2021 ◽  
Vol 45 (4) ◽  
pp. 525-533
Author(s):  
P.A. Khorin ◽  
S.G. Volotovskiy ◽  
S.N. Khonina
Keyword(s):  
Numerical Simulation ◽  
Spatial Light Modulator ◽  
Optical Detection ◽  
Diffraction Order ◽  
Maximum Intensity ◽  
Wavefront Sensor ◽  
Light Modulator ◽  
Correlation Peak ◽  
Wavefront Aberrations ◽  
Channel Filter

The use of a multichannel wavefront sensor matched with phase Zernike functions to determine the type and magnitude of aberration in the analyzed wavefront is investigated. The approach is based on stepwise compensation of wavefront aberrations based on a dynamically tunable spatial light modulator. As criteria for successful detection, not only the magnitude of the correlation peak, but also the maximum intensity, compactness, and orientation of the distribution in each diffraction order are considered. On the basis of numerical simulation, the efficiency of the proposed approach is shown for detecting both weak and strong (up to a wavelength) wavefront aberrations.

Evaluation of wavefront aberrations induced by overlay errors in stitching computer-generated holograms

2022 ◽  
Vol 152 ◽  
pp. 106944
Author(s):  
YingYing Bai ◽  
ZhiYu Zhang ◽  
TianBao Chen ◽  
RuoQiu Wang ◽  
HongDa Wei ◽  
...  
Keyword(s):  
Wavefront Aberrations ◽  
Computer Generated Holograms

Holographic method for precise measurement of wavefront aberrations

2021 ◽  
Author(s):  
George Krasin ◽  
Nikita Stsepuro ◽  
Iliya Gritsenko ◽  
Michael Kovalev
Keyword(s):  
Precise Measurement ◽  
Holographic Method ◽  
Wavefront Aberrations
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