2021
2021
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Record 397 of
Title:Flower-Shaped Optical Vortex Array
Author(s):Fan, Haihao(1,2); Zhang, Hao(1); Cai, Chenyuan(3); Tang, Miaomiao(1); Li, Hehe(1); Tang, Jie(2); Li, Xinzhong(1,2)Source: Annalen der Physik Volume: 533 Issue: 4 DOI: 10.1002/andp.202000575 Published: April 2021Abstract:Herein, the generation of an optical vortex array dubbed the flower-shaped optical vortex array (FOVA) is proposed and experimentally demonstrated using a single optical path interference method. FOVA is generated by the superposition of even and odd Ince–Gaussian (IG) beams, which have the same degree m and different order p. The number of optical vortices (OVs) in the FOVA is determined based on the values of order p and degree m of the even and odd IG beams. Furthermore, the positive sign of the OVs in the array can be transformed to negative by adding a specific initial phase difference. The OVs vanish and then recover as the initial phase difference increases from 0 to 2π. Moreover, the gradient force and energy flow distribution of the FOVA are studied. The OVA with flower-shaped structure generated herein has potential significance in applications, such as microparticle manipulation and optical measurements. ? 2021 Wiley-VCH GmbHAccession Number: 20210509869988 -
Record 398 of
Title:Research on Ray Tracing Algorithm and Acceleration Techniques using KD-tree
Author(s):Zhou, Jia(1); Wen, Desheng(1)Source: 2021 IEEE 6th International Conference on Intelligent Computing and Signal Processing, ICSP 2021 Volume: Issue: DOI: 10.1109/ICSP51882.2021.9409001 Published: April 9, 2021Abstract:In the field of computer graphics, ray tracing algorithm is a kind of algorithm that can realize global illumination. Using the parallel computing power of GPU to accelerate ray tracing is one of the research hotpots at present. Based on the principle of ray tracing, this paper focuses on analyzing the two major problems of ray tracing algorithm acceleration research. One is the data structure problem, the other is the implementation of traversal algorithm on GPU. Based on the summary of the existing research, this paper discusses the derivation of the intersection of ray and surface element, compares various data structures, and analyzes the traversal algorithm based on KD-tree on GPU. ? 2021 IEEE.Accession Number: 20211910343214 -
Record 399 of
Title:Design of 1550nm adjustable laser lighting source
Author(s):Mei, Chao(1); Chang, Sansan(1); Gao, Bo(1); Yi, Bo(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12065 Issue: DOI: 10.1117/12.2599777 Published: 2021Abstract:Shortwave laser is more and more widely used in gated imaging, tracking and pointing, communication and other fields. For the requirement of 1550nm high power laser source, The paper analyzes the realization way, and realized the 1550nm high power laser lighting source. We use multichannel semiconductor laser coupling to realize the high-power light source, and uses fiber coupling to realize the uniform spot. On this basis, an extended collimator is designed, which achieves 10 times of high-power The beam divergence angle can reach 9 mrad to 90 mrad, and the RMS value can be less than 1/4 of the wavelength at each magnification of the wave phase difference, which can meet the needs of engineering application. ? 2021 SPIE.Accession Number: 20220211437993 -
Record 400 of
Title:A 4F optical diffuser system with spatial light modulators for image data augmentation
Author(s):Li, Baopeng(1,2,3,4); Ersoy, Okan K.(4); Ma, Caiwen(1); Pan, Zhibin(2); Wen, Wansha(1,3); Song, Zongxi(1)Source: Optics Communications Volume: 488 Issue: DOI: 10.1016/j.optcom.2021.126859 Published: June 1, 2021Abstract:This paper proposes a novel image data augmentation method based on the 4F optical diffuser system with two spatial light modulators. The method combines data augmentation methods based on geometric transformations with optical phase diffuser, resulting in a system which is effective and easy-to-use. This method can be used in an all-optical machine learning system or in a hybrid digital-optical system, and its digital implementation can also be used in learning-based computer vision applications. The method was tested in image classification of MNIST dataset. It was demonstrated that the augmented dataset significantly improves the classification accuracy. ? 2021 Elsevier B.V.Accession Number: 20210809969279 -
Record 401 of
Title:Performance Optimization and Experimental Research of Continuous Wave Coherent Wind Lidar
Author(s):Yang, Wuhao(1,2); Zhang, Pu(1); Yang, Xinfeng(3); Chen, Qimin(1,4); Zhao, Wei(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 50 Issue: 4 DOI: 10.3788/gzxb20215004.0401004 Published: April 25, 2021Abstract:Based on the requirement of wind velocity measurement, an all-fiber doppler coherent wind lidar system is built with continuous wave laser source at band 1 550 nm. It is analyzed theoretically for the Carrier-to-noise ratio function of the continuous wave coherent lidar and the weighing function of the wind velocity at different focusing distance on the basis of the lidar equation. A vari-focusing optical antenna with the focusing distance range from 5 m to 200 m is designed and fabricated according to the requirement of wind detection. The optical beam expanding module adopts the Galilean refractive structure with the beam expanding ratio as 23 and the optical quality is close to the diffraction limit. The calibration test is executed by using a rotating motor disk. The rotation speed range of the disk is from -3 000 r/min to +3 000 r/min. The diameter of the disk is 26 cm. While the doppler frequency shift of the line of sight velocity is positive and negative, the correlation coefficients between the velocity measurement data of the lidar system and the theoretical calculation result are 0.998 and 0.993. At the same time the standard deviations of velocity are 0.151 m/s and 0.229 m/s, respectively. The wind lidar is then used to measure the atmospheric wind speed. It works correctly to apply the wind lidar to measure the atmospheric wind velocity. ? 2021, Science Press. All right reserved.Accession Number: 20212010360071 -
Record 402 of
Title:High Efficiency 1.9 Kw Single Diode Laser Bar Epitaxially Stacked with a Tunnel Junction
Author(s):Zhao, Yuliang(1,2); Wang, Zhenfu(1); Demir, Abdullah(5); Yang, Guowen(1,2); Ma, Shufang(3); Xu, Bingshe(3); Sun, Cheng(4); Li, Bo(4); Qiu, Bocang(1)Source: IEEE Photonics Journal Volume: 13 Issue: 3 DOI: 10.1109/JPHOT.2021.3073732 Published: June 2021Abstract:We report on the development of a 940-nm diode laser bar based on epitaxially stacked active regions by employing a tunnel junction structure. The tunnel junction and the device parameters were systematically optimized to achieve high output and power conversion efficiency. A record quasi-continuous wave (QCW) peak power of 1.91 kW at 25 °C was demonstrated from a 1-cm wide bar with a 2-mm cavity length at 1 kA drive current (200 μs pulse width and 10 Hz repetition rate). Below the onset of the thermal rollover, the slope efficiency was as high as 2.23 W/A. The maximum power conversion efficiency of 61.1% at 25 °C was measured at 300 A. Reducing the heatsink temperature to 15 °C led to a marginal increase in the peak power to 1.95 kW. ? 2009-2012 IEEE.Accession Number: 20211710259064 -
Record 403 of
Title:2.86 μm emission and fluorescence enhancement through controlled precipitation of ZnTe nanocrystals in DyF3 doped multicomponent tellurite oxyfluoride glass
Author(s):Wan, Rui(1,2); Wang, Pengfei(1,2); Li, Shengwu(1,2); Ma, Yuan(1,2)Source: Journal of Non-Crystalline Solids Volume: 564 Issue: DOI: 10.1016/j.jnoncrysol.2021.120842 Published: July 15, 2021Abstract:Tellurite oxyfluoride glasses with composition of 71TeO2-10ZnO-10BaF2-4K2O-3Nb2O5-2TiO2 doped with different concentrations of DyF3 (0.3, 0.4, 0.5, 0.7, 1 wt%) were prepared by melt-quenching method under dry O2 atmosphere. Under 808 nm laser pumping, infrared (IR) fluorescence emission with central wavelength of 2.86 μm was detected. Basing on the Judd-Ofelt (J-O) theory, the intensity parameters (Ωλ, λ=2, 4 and 6) and radiative property were calculated and characterized through the transmission and fluorescence spectra. The tellurite oxyfluoride glass had high thermal stability and large emission cross-section at 2.86 μm (7.82 × 10?21 cm2). DyF3 doped tellurite oxyfluoride glass ceramic were prepared via in-situ crystallization of ZnTe nanocrystals through heat treatment to ameliorate the surrounding environment of rare earth (RE) ions. The tellurite oxyfluoride glass ceramic prepared by heat treatment at 390°C had great enhancement in 2.86 μm fluorescence intensity (about 7 times), longer fluorescence lifetime (126 μs), indicating that the in-situ crystallization method may be helpful for exploring tellurite based high gain laser glass. ? 2021Accession Number: 20211510213134 -
Record 404 of
Title:Tunable all-optical AND logic gates via four-wave mixing based on graphene-on-silicon slot microring resonators
Author(s):Wu, Wei(1,2); Sun, Qibing(1,3); Wang, Guoxi(1,2); Zhang, Lingxuan(1,3); Zhao, Wei(1,2)Source: Optics and Laser Technology Volume: 138 Issue: DOI: 10.1016/j.optlastec.2021.106926 Published: June 2021Abstract:We propose a novel graphene-on-silicon organic hybrid slot microring resonator (GSHMIR) for tunable all-optical logic gates, which could offer broadband ultra-flattened dispersion with multiple zero-dispersion wavelengths (ZDWs) and high nonlinearity coefficient of 1.67 × 104 W?1m?1. Further investigations on temporal evolution dynamics for all-optical logic function suggest that the third-order dispersion will induce the temporal drift and tail oscillation of output pulses. The tunable all-optical AND logic function over the wavelength range from 1536 nm to 1569 nm could be obtained for 40 Gb/s signals with the conversion efficiency as high as ?6.4 dB. These results are essential for all-optical wavelength division multiplexer (WDM) technology of future integrated optoelectronic systems, as well as providing a novel architecture for on-chip optical communications. ? 2021 Elsevier LtdAccession Number: 20210509855656 -
Record 405 of
Title:Analysis of a higher-energy structure in nanotip enhanced fields
Author(s):Gao, Xu-Zhen(1,2,3); Landsman, Alexandra S.(4); Wang, Hushan(1); Huang, Pei(1); Zhang, Yanpeng(2); Wang, Bo(1); Wang, Yishan(1); Cao, Huabao(1); Fu, Yuxi(1); Pi, Liang-Wen(1,3)Source: New Journal of Physics Volume: 23 Issue: 11 DOI: 10.1088/1367-2630/ac320c Published: November 2021Abstract:We investigate strong field ionization of an atomic gas in a plasmonically enhanced field resulting from the illumination of a nanometer-sized structure with ultrafast laser pulse. We use perturbation theory to derive an approximate solution for electron's motion following ionization. These analytical estimates are corroborated by the time-dependent Schr?dinger equation and classical trajectory Monte Carlo simulations. Notably, our approach can be used to obtain electron energy spectra without having to rely on numerical simulations. This allows for a deeper study of the dependence of electron energy spectrum on the properties of the near-field, suggesting electric field sensor applications. We derive an analytical expression for the location of the peak of the higher-energy structure (HES) as a function of laser parameters and near-field decay length.We find a particularly strong dependence of the energy peak on laser frequency, with lower frequencies causing a significant upward shift in the final electron energies. Combined with control of the width of the HES, which can be done by changing the size of the nanostructure, this points to the possibility of using nanotips as sources of ultrashort electron beams of tunable energy. ? 2021 The Author(s).Accession Number: 20214811229521 -
Record 406 of
Title:Progress in Study and Application of Optical Field Modulation Technology Based on Liquid Crystal Spatial Light Modulators (Invited)
Author(s):Zhou, Yuan(1,2); Li, Runze(1); Yu, Xianghua(1); Yan, Shaohui(1); Li, Xing(1,2); Gao, Wenyu(1,2); Liu, Chao(1,2); Peng, Tong(1); Yang, Yanlong(1); Min, Junwei(1); Wang, Ping(1,3); Qu, Jun(4); Yao, Baoli(1,2)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 50 Issue: 11 DOI: 10.3788/gzxb20215011.1123001 Published: November 25, 2021Abstract:As an electromagnetic wave, optical field can be described by using parameters of amplitude, phase and polarization. Spatial optical field modulation technology enables to generate novel spatially structured optical field by modulating these parameters. Compared with other types of modulation devices, the liquid crystal spatial light modulator has the advantages of high diffraction efficiency, millions of modulated pixels, and real-time dynamic modulation. It has become the mainstream device for spatial optical field modulation. In this paper, we first give an introduction to the principles and algorithms of optical field modulation technology, including single-parameter modulation, complex amplitude modulation, and multi-parameter modulation by using the liquid crystal spatial light modulators. Some applications of these optical modulation technologies in holographic optical tweezers, optical microscopy, optical information storage, optical micromachining, imaging behind scattering media, and optical communication are exampled. Then we discuss the problems to be resolved, the development trends and the development prospects of the technology. The purpose of this paper is to help researchers systematically understand the principle, the latest research progress and the potential application of the optical field modulation technology based on the liquid crystal spatial light modulators, and provide some references for research in this field. ? 2021, Science Press. All right reserved.Accession Number: 20215011322429 -
Record 407 of
Title:Spatio-temporal Resolution Studies on a Synchronous Streak Tube
Author(s):Tian, Liping(1); Shen, Lingbin(1); Chen, Lin(1); Li, Lili(2); Chen, Ping(2); Tian, Jinshou(2)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 50 Issue: 4 DOI: 10.3788/gzxb20215004.0404002 Published: April 25, 2021Abstract:A synchronous streak tube capable of providing high spatial resolution, high temporal resolution and large working area is numerically designed and experimentally demonstrated. In this paper, a 3-D model developed to systematically and comprehensively analyze the dependence of the physical temporal resolution on the accelerating voltage, the spatial resolution on the deflector-to-cathode distance, the dynamic spatial resolution and temporal resolution on the scanning velocity. Finally, geometry and electric parameters of dDC=100 mm, Ug=700 V, and Tscreen= 0.5 ns are proposed to optimize the streak tube performances. The numerical simulations show that the static spatial resolution is higher than 25 lp/mm@MTF=10% and the dynamic spatial resolution is higher than 16 lp/mm@MTF=10% over the whole effective photocathode area of 18 mm×2 mm. And, the simulated temporal resolution is better than 5.6 ps at Tscreen=0.5 ns. Furthermore, the photocathode radiant sensitivity can reach 51 mA/W at the wavelength of 400 nm. The tested static spatial resolution is as high as 25 lp/mm@CTF=13%. ? 2021, Science Press. All right reserved.Accession Number: 20212010359869 -
Record 408 of
Title:The dual-injection Ge-on-Si photodetectors with high saturation power by optimizing light field distribution
Author(s):Cui, Jishi(1); Li, Tiantian(2); Yang, Fenghe(3); Cui, Wenjing(1); Chen, Hongmin(1)Source: Optics Communications Volume: 480 Issue: DOI: 10.1016/j.optcom.2020.126467 Published: 1 February 2021Abstract:In this work, we put forward the length design principle of the dual-injection integrated Ge-on-Si photodetectors based on the characteristics of the light field distribution. When the length of the absorption layer makes the maximum intensity of the incident light from both ends are alternately distributed, the light field distribution is more uniform. Based on this principle, the shorter photodetector could get better saturation performance. Two dual-injection photodetectors with the length of 6μm and 10μm have been investigated, the experimental results show that the saturation current of 6μm length device is 18.33% higher, and the bandwidth is 138.60% higher at 10 mW incident power comparing with the 10μm length device. The 6μm length photodetector realized a responsivity of 1.07 A/W, a bandwidth of 37.3 GHz at 50 μW luminous power @1550 nm. ? 2020 Elsevier B.V.Accession Number: 20203909239219