2021
2021
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Record 25 of
Title:A four-channel ICCD framing camera with nanosecond temporal resolution and high spatial resolution
Author(s):Fang, Yuman(1,2); Zhang, Minrui(1); Wang, Junfeng(1); Guo, Lehui(1,2); Liu, Xueling(1,2); Lu, Yu(1); Tian, Jinshou(1,3)Source: Journal of Modern Optics Volume: 68 Issue: 13 DOI: 10.1080/09500340.2021.1937735 Published: 2021Abstract:In this paper, a high spatial resolution, high gating speed framing camera capable of four separate two-dimensional images is designed and tested. A mirror-based image splitter has been designed and developed to provide a separate image for each arm with equal path length and equal intensity splitting while having a spectral flat response. Fast gating of a single frame is accomplished by using a proximity-focused microchannle-plate image-intensifier?(MCPII) gated by a MOSFET-based pulse module with adjustable gate width from 3 ns to D.C. operation. Multiple frames are obtained by using multiple gated tubes with time intervals between consecutive frames can be adjusted flexibly. Its spatial resolution reaches 36.5 lp/mm with each frame having a 4.6-ns gate width. Furthermore, a three-dimensional MCPII?model is developed to investigate the transit time and spatial resolution of the proximity-focused MCPII based on the Finite Integral Technique (FIT) and Monte Carlo method (M–C method). ? 2021 Informa UK Limited, trading as Taylor & Francis Group.Accession Number: 20212610550244 -
Record 26 of
Title:Compact portable laser system for transportable communication band ultra-narrow linewidth laser
Author(s):Zhang, Linbo(1,2); Jiao, Dongdong(1); Guo, Xinqian(1); Fan, Le(1); Xu, Guanjun(1); Liu, Tao(1); Zhang, Shougang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12057 Issue: DOI: 10.1117/12.2603696 Published: 2021Abstract:Ultra-narrow linewidth laser plays a very important role in the high-precision optical frequency transfer via optical fibers. We have designed and realized a compact portable laser system for transportable communication band ultra-narrow linewidth laser. Based on the method of topology optimization design, a stable optical board is developed. Designed and developed a series of small optical grade devices without exercise rules, making the optical system more stable. The optical system we designed is suitable for transportable ultra-narrow linewidth laser. ? 2021 COPYRIGHT SPIE.Accession Number: 20215211375462 -
Record 27 of
Title:Collective energy-spectrum broadening of a proton beam in a gas-discharge plasma
Author(s):Cheng, Rui(1,6,7); Hu, Zhang-Hu(2); Hui, De-Xuan(2); Zhao, Yong-Tao(1,3); Chen, Yan-Hong(1); Gao, Fei(2); Lei, Yu(1); Wang, Yu-Yu(1); Zhu, Bing-Li(4); Yang, Yang(4); Wang, Zhao(1,5); Zhou, Ze-Xian(1,5); Wang, You-Nian(2); Yang, Jie(1)Source: Physical Review E Volume: 103 Issue: 6 DOI: 10.1103/PhysRevE.103.063216 Published: June 2021Abstract:An accurate understanding of ion-beam transport in plasmas is crucial for applications in inertial fusion energy and high-energy-density physics. We present an experimental measurement on the energy spectrum of a proton beam at 270 keV propagating through a gas-discharge hydrogen plasma. We observe the energies of the beam protons changing as a function of the plasma density and spectrum broadening due to a collective beam-plasma interaction. Supported by linear theory and three-dimensional particle-in-cell simulations, we attribute this energy modulation to a two-stream instability excitation and further saturation by beam ion trapping in the wave. The widths of the energy spectrum from both experiment and simulation agree with the theory. ? 2021 American Physical Society.Accession Number: 20212710589837 -
Record 28 of
Title:Optical data transmissionwith high spectral efficiency at44Terabits/s with a soliton crystal micro-comb
Author(s):Tan, M.(1); Corcoran, B.(2); Xu, X.(2); Wu, J.(1); Boes, A.(3); Nguyen, T.(3); Chu, S.(4); Little, B.(5); Morandotti, R.(6,7); Mitchell, A.(3); Moss, D.J.(1)Source: Optics InfoBase Conference Papers Volume: Issue: DOI: null Published: 2021Abstract:We report data transmission over 75km in the lab and a field trial, at 44.2 Tb/s over standard optical fibre using a single integrated chip source, reaching a spectral efficiency of 10.4 bits/s/Hz. ? 2021 OSA - The Optical Society. All rights reserved.Accession Number: 20214911288208 -
Record 29 of
Title:Photonic convolutional accelerator and neural network in the Tera-OPs regime based on soliton crystal Kerr microcombs
Author(s):Tan, M.(1); Xu, X.(2); Wu, J.(1); Boes, A.(3); Corcoran, B.(2); Nguyen, T.(3); Chu, S.T.(4); Little, B.E.(5); Morandotti, R.(6); Lowery, A.J.(2); Mitchell, A.(3); Hicks, D.(1,7); Moss, D.J.(1)Source: Optics InfoBase Conference Papers Volume: Issue: DOI: null Published: 2021Abstract:We report a new approach to ONNs based on integrated Kerr micro-combs that is programmable, highly scalable and capable of reaching ultra-high speeds. We demonstrate a single neuron perceptron at 11.9 Giga-OPS at 8 bits per OP, or 95.2 Gbps. We then demonstrate a convolutional accelerator operating beyond 11 TeraOPs/s. We test the perceptron on handwritten-digit recognition and cancer-cell detection - achieving over 90% and 85% accuracy, respectively. ? 2021 OSA - The Optical Society. All rights reserved.Accession Number: 20214911288210 -
Record 30 of
Title:Using cnn and hht to predict blood pressure level based on photoplethysmography and its derivatives
Author(s):Sun, Xiaoxiao(1,2); Zhou, Liang(1); Chang, Shendong(3); Liu, Zhaohui(1)Source: Biosensors Volume: 11 Issue: 4 DOI: 10.3390/bios11040120 Published: 2021Abstract:According to the WTO, there were 1.13 billion hypertension patients worldwide in 2015. The WTO encouraged people to check the blood pressure regularly because a large amount of patients do not have any symptoms. However, traditional cuff measurement results are not enough to represent the patient0s blood pressure status over a period of time. Therefore, there is an urgent need for portable, easy to operate, continuous measurement, and low-cost blood pressure measuring devices. In this paper, we adopted the convolutional neural network (CNN), based on the Hilbert–Huang Transform (HHT) method, to predict blood pressure (BP) risk level using photoplethysmography (PPG). Considering that the PPG0s first and second derivative signals are related to atherosclerosis and vascular elasticity, we created a dataset called PPG+, the images of PPG+ carry information on PPG and its derivatives. We built three classification experiments by collecting 582 data records (the length of each record is 10 s) from the Medical Information Mart for Intensive Care (MIMIC) database: NT (normotension) vs. HT (hypertension), NT vs. PHT (prehypertension), and (NT + PHT) vs. HT, the F1 scores of the PPG + experiments using AlexNet were 98.90%, 85.80%, and 93.54%, respectively. We found that, first, the dataset established by the HHT method performed well in the BP grade prediction experiment. Second, because the Hilbert spectra of the PPG are simple and periodic, AlexNet, which has only 8 layers, got better results. More layers instead increased the cost and difficulty of training. ? 2021 by the authors.Accession Number: 20231213755644 -
Record 31 of
Title:Laser beam jitter control of the link in free space optical communication systems
Author(s):Wang, Xuan(1,2,3); Su, Xiuqin(1); Liu, Guizhong(2); Han, Junfeng(1); Wang, Rui(1,3); Wang, Kaidi(1,3)Source: Optics Express Volume: 29 Issue: 25 DOI: 10.1364/OE.443411 Published: December 6, 2021Abstract:The pointing and tracking performance of laser beams in free space optical communi-cation (FSOC) systems and other precision laser systems is severely limited by beam jitter. This research proposes an adaptive control method to suppress beam jitter by adjusting the deflection angle of the beam by controlling the fast steering mirror (FSM) driven by piezoelectric ceramics. In order to verify the effectiveness of the control method, we have established an experimental platform. First, the internal controller of the FSM is adjusted to an approximately linear system, aiming to turn the input and output control signals into a linear relationship. Based on the adaptive filter, a filtered-x variable step-size normalized least mean square (FxVSNLMS) algorithm is proposed. To further improve the robustness of the controller, a Proportion Integral Differential (PID) controller and an adaptive controller which work in parallel are then added to the control loop. Finally, experimental results are provided and compare with the traditional controller and other adaptive control methods. Experimental results show that for more complex narrow-band and broad-band mixed beam disturbances, the control scheme developed in this research is significantly improved. This conclusion has also been verified on the ground experimental platform of FSOC. ? 2021 Optical Society of America under the terms of the OSA Open Access Publishing AgreementAccession Number: 20214911285705 -
Record 32 of
Title:Tera-OP/s Neuromorphic Processing with Kerr Microcombs
Author(s):Tan, M.(1); Xu, X.(1,2); Wu, J.(1); Boes, A.(3); Corcoran, B.(3); Nguyen, T.(3); Chu, S.T.(4); Little, B.E.(5); Morandotti, R.(6); Hicks, D.G.(1,7); Mitchell, A.(3); Moss, David J.(1)Source: Optics InfoBase Conference Papers Volume: Issue: DOI: null Published: 2021Abstract:We report optical neuromorphic processors based on Kerr micro-combs that are programmable, scalable and ultra-high speed. We demonstrate a perceptron at 11.9Giga-OPS at 8 bits, or 95.2 Gbps, and a convolutional accelerator at 11TeraOPs/s. ?2021 The Author (s).Accession Number: 20214911288098 -
Record 33 of
Title:Indium selenide saturable absorber for high-energy nanosecond Q-switched pulse generation
Author(s):Li, Lu(1); Wang, Yao(1); Jin, Wei(1); Zhao, Qiyi(1); Su, Yulong(2)Source: Applied Optics Volume: 60 Issue: 2 DOI: 10.1364/AO.414750 Published: January 10, 2021Abstract:As a kind of III/VI group compound 2D layered material, indium selenide (In2Se3) has attracted tremendous interest because of its favorable optoelectronic characteristics. Here, magnetron sputtering deposition (MSD) technology was employed to prepare an In2Se3-based saturable absorber (SA). The nonlinear optical properties of this SA, whose modulation depth (1T) is 6.18%, were studied. With the aid of its saturable absorption, a stable two-wavelength Q-switching Er-doped fiber (EDF) laser was established. When pump power was adjusted to 900 mW, the output power was increased to 63.84 mW. The shortest pulse duration and maximum pulse energy were estimated to be 556 ns and 376 nJ, respectively. The signal-to-noise ratio of 70 dB proves this fiber laser has high stability. In comparison with previous works, the laser performance in this study is improved significantly. These results indicate that the In2Se3 holds promise as an outstanding candidate for high-energy pulse generation and will advance the development of In2Se3-based nonlinear photonics devices. ? 2021 Optical Society of AmericaAccession Number: 20211310151897 -
Record 34 of
Title:Research on Deep Learning Denoising Method in an Ultra-Fast All-Optical Solid-State Framing Camera
Author(s):Zhou, Jian(1); Wang, Zhuping(2); Wang, Tao(3); Yang, Qing(4); Wen, Keyao(3); Yan, Xin(3); He, Kai(3); Gao, Guilong(3); Yao, Dong(3); Yin, Fei(3,4)Source: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) Volume: 12736 LNCS Issue: DOI: 10.1007/978-3-030-78609-0_7 Published: 2021Abstract:The ultra-fast all-optical solid-state framing camera (UASFC) is a new type of X-ray ultra-fast diagnostic technology. It uses X-ray excitation to change the refractive index distribution of the ultra-fast detection chip, and time-tuned multi-wavelength probe light for ultra-fast detection on the order of picoseconds or less. Due to the uneven intensity of the probe light wavelength and spatial diffraction, the noise of the detection image is too high, which directly affects the spatial and temporal resolution of the system. To improve the detection performance of the UASFC system, we adopted NLM image optimization technology based on a convolutional neural network, using 50 shots of the reticle image as the learning set and iterating the weight of the NLM image optimization filter. The CCD image obtained by the four-channel wavelength spectroscopy system is noise-reduced and optimized, which greatly improves the image contrast and edge definition, reduces image noise, and further improves the time and space resolution of the UASFC system. ? 2021, Springer Nature Switzerland AG.Accession Number: 20213310764473 -
Record 35 of
Title:Enhanced upconversion emission of NaGdF4: Yb3+/Tm3+ crystals by introducing Li+ ions for anti-counterfeiting recognition
Author(s):Li, Dongdong(1); Mo, Jianye(1); Wang, Chong(1); Wu, Zhiwei(1); Hao, Aihua(1); She, Jiangbo(2)Source: Applied Physics A: Materials Science and Processing Volume: 127 Issue: 7 DOI: 10.1007/s00339-021-04674-8 Published: July 2021Abstract:The upconversion efficiency could be affected by Li+ ions with changing the local crystal field of nanoparticles. Therefore, a series of NaGdF4:Yb3+/Tm3+ micro-particles with different Li+ doping concentrations were synthesized and investigated, respectively. The structure and morphology of the synthesized materials were tested by X-ray diffraction and scanning electron microscope. The photoluminescence properties were studied with different concentrations Li+ ions doping under the irradiation of 980?nm laser. The emission peaks of Tm3+ ions are 449, 477, 645, 723, 800?nm which are attributed to high excited states to ground state 3H6 transition through a multiple steps resonance energy transfer from excited Yb3+. The enormous increase in upconversion emission in upconversion micro-particles (UCMPs) by introducing Li+ ions was observed by the naked eye. The strongest photoluminescence intensity is the sample with 2.5% doped Li+ ions. Additionally, the practicality of the resultant UCMPs for photoluminescence visible imaging was systematically investigated. These results suggest that the Li+ doped NaGdF4: Yb3+/Tm3+ is very promising as a screen printing material for anti-counterfeiting recognition. ? 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.Accession Number: 20212410514876 -
Record 36 of
Title:Sparse constrained low tensor rank representation framework for hyperspectral unmixing
Author(s):Dong, Le(1,2); Yuan, Yuan(3)Source: Remote Sensing Volume: 13 Issue: 8 DOI: 10.3390/rs13081473 Published: April 2, 2021Abstract:Recently, non-negative tensor factorization (NTF) as a very powerful tool has attracted the attention of researchers. It is used in the unmixing of hyperspectral images (HSI) due to its excellent expression ability without any information loss when describing data. However, most of the existing unmixing methods based on NTF fail to fully explore the unique properties of data, for example, low rank, that exists in both the spectral and spatial domains. To explore this low-rank structure, in this paper we learn the different low-rank representations of HSI in the spectral, spatial and non-local similarity modes. Firstly, HSI is divided into many patches, and these patches are clustered multiple groups according to the similarity. Each similarity group can constitute a 4-D tensor, including two spatial modes, a spectral mode and a non-local similarity mode, which has strong low-rank properties. Secondly, a low-rank regularization with logarithmic function is designed and embedded in the NTF framework, which simulates the spatial, spectral and non-local similarity modes of these 4-D tensors. In addition, the sparsity of the abundance tensor is also integrated into the unmixing framework to improve the unmixing performance through the L2,1 norm. Experiments on three real data sets illustrate the stability and effectiveness of our algorithm compared with five state-of-the-art methods. ? 2021 by the authors. Licensee MDPI, Basel, Switzerland.Accession Number: 20211710243143