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Record 385 of
Title:One-dimensional purely Lee-Huang-Yang fluids dominated by quantum fluctuations in two-component Bose-Einstein condensates
Author(s):Liu, Xiuye(1,2); Zeng, Jianhua(1,2)
Source: Chaos, Solitons and Fractals Volume: 160 Issue: DOI: 10.1016/j.chaos.2022.112240 Published: July 2022
Abstract:Lee-Huang-Yang (LHY) fluids are an exotic quantum matter dominated purely by quantum fluctuations. Recently, the three-dimensional LHY fluids were observed in ultracold atoms experiments, while their low-dimensional counterparts have not been well known. Herein, based on the Gross-Pitaevskii equation of one-dimensional LHY quantum fluids in two-component Bose-Einstein condensates, we reveal analytically and numerically the formation, properties, and dynamics of matter-wave structures therein. Considering a harmonic trap, approximate analytical results are obtained based on variational approximation, and higher-order nonlinear localized modes with nonzero nodes are constructed numerically. Stability regions of all the LHY nonlinear localized modes are identified by linear-stability analysis and direct perturbed numerical simulations. Movements and oscillations of single localized mode, and collisions between two modes, under the influence of different initial kicks are also studied in dynamical evolutions. The predicted results are available to quantum-gas experiments, providing a new insight into LHY physics in low-dimensional settings. ? 2022 Elsevier Ltd
Accession Number: 20222112156628
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Record 386 of
Title:Quadriwave Lateral Shearing Interferometry Quantitative Phase Imaging Based on 2D Ronchi Phase Grating
Author(s):Song, Jinwei(1,2); Min, Junwei(1); Yuan, Xun(1,2); Xue, Yuge(1,2); Yao, Baoli(1,2)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 51 Issue: 11 DOI: 10.3788/gzxb20225111.1118001 Published: November 2022
Abstract:Quantitative Phase Imaging （QPI） is a technique that can measure the phase map of the light field. It has the characteristics of label-free， non-invasive and three-dimensional observation and has been widely used in bioimaging and industrial inspection. A number of techniques have been developed to measure phase information of objects， including the interferometric method such as Digital Holographic Microscopy （DHM）， and the non-interferometric method such as the Fourier Ptychography Microscopy （FPM）， Transport of Intensity Equation （TIE） method and so on. The interferometric method has high measurement accuracy but a complex experimental setup sensitive to the environmental disturbance. The non-interferometric method recovers phase from the intensity patterns of objects， but requires iterative calculation or multiple images recorded at different positions， which makes the imaging speed slow and unsuitable for real-time observation. The quantitative phase imaging based on Quadriwave Lateral Shearing Interferometry （QLSI） has the advantages of the referenceless beam， simple configuration， high stability and fast imaging speed. In the existing studies， Cross Grating （CG）， Modified Hartmann Mask （MHM）， Randomly Encoded Hybrid Grating （REHG） and other splitter elements were used for QLSI. The cross grating has low diffraction efficiency and energy utilization rate （~10%） for the four beams of first-order diffraction. The MHM and REHG can concentrate the diffracted light energy on the four first-order diffraction beams. But the MHM still has a low energy utilization rate （~37%）， and the REHG has a complex structure for fabrication. This paper proposes a quantitative phase imaging method based on QLSI using a two-dimensional （2D） Ronchi phase grating. The light incident to the 2D Ronchi phase grating is diffracted mainly with energy concentrated on the four first-order diffraction beams， occupying 65.7% of the total incident energy. The object light carrying the sample's phase information is imprinted to the 2D Ronchi phase grating and then copied into four beams， which interfere with each other to produce the quadriwave lateral shearing interferogram. The quantitative phase image of the sample is reconstructed by Fourier analysis of the interferogram. The influence of the grating period on the QLSI imaging is analyzed theoretically， and the optimal grating period is determined to be six times of the pixel size of the detector. This match can make the best use of the spatial bandwidth product of detector and achieve high resolution image. The influence of the illumination wavelength on the phase reconstruction is theoretically analyzed， which shows that the proposed method is insensitive to the illumination wavelength. The feasibility of quantitative phase imaging under wide spectral light illumination source is demonstrated. The compact QLSI module is constructed with the pixel size of 9 μm×9 μm of the detector and the period of 54 μm of the 2D Ronchi grating. The grating period is precisely six times of the pixel size， meeting the requirement of the optimal condition. The QLSI module is directly connected to a conventional optical microscope to implement the QPI imaging of e.g.， Polymethyl Methacrylate （PMMA） microspheres， microlens arrays and staphylococcus section. The relative error of phase experimentally measured is about 1.8%， proving that the method has a high precision of phase measurement. The experimental results also show that the method can be used for quantitative phase imaging with a wide-spectrum light source， making it easily combined with conventional optical microscopes to have a great application potential in biomedicine， three-dimensional topography measurement and other related fields. ? 2022 Chinese Optical Society. All rights reserved.
Accession Number: 20224513074944
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Record 387 of
Title:Large-field lattice structured illumination microscopy
Author(s):Zheng, Juanjuan(1,2); Fang, Xiang(1); Wen, Kai(1); Li, Jiaoyue(1); Ma, Ying(1); Liu, Min(1); An, Sha(1,2); Li, Jianlang(1); Zalevsky, Zeev(3); Gao, Peng(1)
Source: Optics Express Volume: 30 Issue: 15 DOI: 10.1364/OE.461615 Published: July 18, 2022
Abstract:In this paper, we present large-field, five-step lattice structured illumination microscopy (Lattice SIM). This method utilizes a 2D grating for lattice projection and a spatial light modulator (SLM) for phase shifting. Five phase-shifted intensity images are recorded to reconstruct a super-resolution image, enhancing the imaging speed and reducing the photo-bleaching both by 17%, compared to conventional two-direction and three-shift SIM. Furthermore, lattice SIM has a three-fold spatial bandwidth product (SBP) enhancement compared to SLM/DMDbased SIM, of which the fringe number is limited by the SLM/DMD pixel number. We believe that the proposed technique will be further developed and widely applied in many fields. ? 2022 Optica Publishing Group.
Accession Number: 20222912380275
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Record 388 of
Title:A hybrid method combining discharge-assisted laser induced breakdown spectroscopy with wavelet transform for trace elemental analysis in liquid targets
Author(s):Xu, Boping(1,2); Liu, Simeng(1,2); Lei, Bingying(1,2); Liu, Yinghua(1,2); Zhang, Wenfu(1,2); Tang, Jie(1,2); Wang, Yishan(1,2); Zhao, Wei(1,2); Duan, Yixiang(3)
Source: Journal of Analytical Atomic Spectrometry Volume: 37 Issue: 6 DOI: 10.1039/d2ja00140c Published: May 6, 2022
Abstract:Laser-induced breakdown spectroscopy (LIBS) represents a highly promising detection technology for the quantitative determination of trace elements in liquids. However, due to plasma fast quenching, liquid level instability, and limited laser-energy absorption, rapid real-time quantitative detection of trace elements with high-sensitivity in liquid targets remains significantly challenging. Here, a feasible hybrid method of discharge-assisted laser-induced breakdown spectroscopy (D-LIBS) with wavelet transform de-noising (WTDN) was proposed for trace metal element analysis in oil pollutants. Compared to conventional laser-induced breakdown spectroscopy (C-LIBS), this method has the capacity to increase signal intensities of trace metal elements by one order of magnitude. For the Ca element, the signal to noise ratio (SNR) is increased by 16-fold with the optimal wavelet basis and decomposition layer in WTDN. Examining the LoDs of Al, Ba, Ca, Cr, Fe, Na, and Zn shows that D-LIBS with WTDN allows the LoDs to be lowered to 1/2-1/24 of the original level. And the LoDs of Ca and Ba are measured to be as low as 0.32 mg L?1 and 0.69 mg L?1, respectively, which are reduced by one order of magnitude compared to those of C-LIBS. Moreover, the standard addition method analyzed the recoveries of Ba and Fe elements in the real samples of spiked lubricating oils to evaluate the method’s trueness. Superior accuracy and repeatability are obtained by D-LIBS, and the mean recoveries are in the range of 101.81-105.45%. In addition, partial least squares regression (PLSR) and support vector regression (SVR) models were established to predict the metal concentration. Thanks to this hybrid method, the PLSR model allows the coefficient of determination (RP2) to increase from 0.4710 to 0.9250, and the SVR model allows the RP2 to increase from 0.4590 to 0.9876. Our work provides an alternative, economical, and reliable method for rapid real-time quantitative analysis of trace metal elements with high-sensitivity in various industrial applications associated with oil pollutants. ? 2022 The Royal Society of Chemistry
Accession Number: 20222812338068
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Record 389 of
Title:Numerical modeling and optimization of hundred-watt-level 2.8 μm and 1.6 μm cascaded heavily-erbium-doped fluoride fiber amplifiers
Author(s):Xiao, Yang(1,2); Xiao, Xusheng(1,2); Xu, Yantao(1,2); She, Shengfei(1,2); Liu, Chengzhen(1,2); Guo, Haitao(1,2)
Source: Optics and Laser Technology Volume: 155 Issue: DOI: 10.1016/j.optlastec.2022.108418 Published: November 2022
Abstract:We propose a continuous-wave dual-seed cascaded heavily erbium-doped fluoride fiber amplifier scheme with a 981 nm bi-directional pump configuration for hundred-watt-level power scaling for the first time. When the powers of the 2.8 μm and 1.6 μm seed lasers and the total pump light are 5 W, 20 W, and 300 W, respectively, the 2.8 μm laser theoretically achieves an output power of ～100 W. The amplifier scheme can also reduce the fiber temperature. Additionally, the results show that there is no excited state absorption at ～1.675 μm, and thus injecting a 1.675 μm laser to the amplifier is not conducive to the power scaling. ? 2022 Elsevier Ltd
Accession Number: 20222812352552
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Record 390 of
Title:Human action recognition by multiple spatial clues network
Author(s):Zheng, Xiangtao(1); Gong, Tengfei(1); Lu, Xiaoqiang(1); Li, Xuelong(2)
Source: Neurocomputing Volume: 483 Issue: DOI: 10.1016/j.neucom.2022.01.091 Published: April 28, 2022
Abstract:Human action can be recognized in still images since the whole image represents an action with some spatial clues, such as human poses, action-specific parts, and global surroundings. To represent the spatial clues, the recent methods require labor-intensive annotations to locate the human body and objects, which are computationally intensive. To eliminate strong supervision, a Multiple Spatial Clues Network (MSCNet) is proposed to represent the spatial clues with only image-level action label. Neither accurately manual annotated bounding boxes nor extra labeled datasets are required as additional supervision. First, the proposed MSCNet exploits spatial-attention module to generate spatial attention regions, and detects the spatial clues with minimal supervision. Then, spatial clues exploitation is proposed to utilize the learned spatial clues with three modules: the context module, body + context module and body + semantics module. Experiments on three benchmark datasets demonstrate the effectiveness of the proposed MSCNet. ? 2022 Elsevier B.V.
Accession Number: 20220711630605
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Record 391 of
Title:The Effect of Temperature and Salinity on Imaging Quality of Optical System in Underwater Turbulence
Author(s):Sun, Shuwei(1,2,3); Wang, Hao(2,3); Wang, Wei(1,2); Li, Peng(1,2); Kang, Fuzeng(2); Xie, Xiaoping(1,2)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 51 Issue: 12 DOI: 10.3788/gzxb20225112.1211004 Published: 2022
Abstract:Underwater imaging technology is a critical means to explore the ocean. With the development of underwater imaging technology，it is found that underwater turbulence is an important factor that restricts the imaging quality of optical system. Turbulence is a phenomenon of small vortices occurring at the interface due to different flow rates of each part of the medium. This physical phenomenon can directly lead to changes in the refractive index of the medium. Thus，it can change the wavefront structure of the beam，affect the modulation transfer function，and ultimately cause the degradation of the image quality at the receiving end. Most of the studies about turbulence on beam is based on refractive index and power spectrum，and the researches on turbulence is based on Nikishov's power spectrum. In this power spectrum，eddy diffusion rate is constant，does not relate to the average water temperature and the average salinity which can influence on eddy diffusion rate. Thus，the turbulence caused by the refractive index models still needs further refinement. Later，some scholars improved the refractive index fluctuation power spectrum. In this model，the average temperature and average salinity are used to characterize the vortex diffusion rate，and the refractive index fluctuation power spectrum model based on temperature and salinity is established. Compared with Nikishov's power spectrum，the power spectrum model is more complete，but the temperature variance dissipation rate and kinetic energy dissipation rate used to characterize turbulence intensity cannot be measured in the experiment，resulting in a gap between the simulation model and practical applications. In order to study the effect of underwater turbulence on the imaging quality of optical systems，we deduced the wave structure function and established an underwater optical imaging model based on the refractive index fluctuation power spectrum contained with temperature and salinity. The effects of temperature and salinity on the modulation transfer function under turbulent conditions are simulated. For verifying the reliability of the turbulence imaging model，a 3-m long underwater optical imaging experiment platform is designed and built. A water pump and water tank are used to create a turbulence region with controllable turbulence intensity. A CCD camera also plays a part of the region to image the resolution plate，thus analyzing the imaging quality. By controlling the experimental conditions，the imaging results under different temperatures and different salinity conditions are obtained. On this basis，the modulation transfer function is analyzed after the ensemble average obtained by several experiments. The results show that the modulation transfer function of the image decreases with the increase of temperature and salinity. Further studies show that the contrast of different spatial frequencies decreases linearly with the increase of salinity，and the decrease amplitude is basically the same. With the increase of temperature，the MTF basically conforms to the linear decline law，and the MTF of high-frequency components decreases faster. The experimental results show that the imaging quality under turbulent conditions is affected more by temperature than salinity，and the experimental results are consistent with the simulation results. This research has certain reference value for the design optimization and development of underwater optical systems. ? 2022 Chinese Optical Society. All rights reserved.
Accession Number: 20230813622816
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Record 392 of
Title:Optimal bright multimode quantum squeezing via multi-seeding energy-level cascaded four-wave mixing
Author(s):Jiawei, Li(1,2,3); Jianhua, Zeng(2,3); Feng, Li(1); Yanpeng, Zhang(1); Yin, Cai(1)
Source: Optics Express Volume: 30 Issue: 22 DOI: 10.1364/OE.463900 Published: October 24, 2022
Abstract:Quantum Squeezing is one of the most important quantum resources in quantum optics and quantum information. In particular, multimode quantum squeezing, with ultra-low quantum fluctuations and quantum correlations amongst many optical modes, is essential for realizing multipartite entanglement and quantum precision measurements. In this paper, we propose an all-optically controlled scheme to generate three-mode bright quantum correlated beams from energy-level cascaded four-wave mixing (ELC-FWM). By using a linear modes transform approach, the input-output relation and the covariance matrix of the produced states are obtained. Moreover, single-, double- and triple-seeding conditions are investigated to measure the quantum squeezing properties. We find that various permutations of two- and three-mode quadrature squeezing can be generated and optimized to reach the corresponding limit, via only modulating the ratio of the multiple seeds, without need of any post-operating linear optics, e.g., beam splitters. Such weak seeding light controlled scheme suggests the modulation and the optimization of multimode quantum states might be operated at photons-level, providing a reconfigurable and integrated strategy for complex quantum information processing and quantum metrology. ? 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.
Accession Number: 20224313002036
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Record 393 of
Title:Direct Amination of Benzene with Molecular Nitrogen Enabled by Plasma-Liquid Interactions
Author(s):Xu, Xia(1); Zhao, Xuyang(1); Tang, Jie(2); Duan, Yixiang(1); Tian, Yong-Hui(1)
Source: Angewandte Chemie - International Edition Volume: 61 Issue: 24 DOI: 10.1002/anie.202203680 Published: June 13, 2022
Abstract:Nitrogen fixation is industrially realized by mass production of ammonia, the principal intermediate nitrogen source for N-containing organic molecules. Instead, direct C?N bond formation from dinitrogen (N2) is of great interest but remains a challenge. Here, by virtue of unique plasma–liquid interactions, we developed an environmentally benign one-pot approach to directly couple benzene and N2, two naturally abundant yet chemically inert molecules, into value-added arylamines. Under the optimal conditions, an amination yield of 45 % was rapidly achieved, far better than the reported benzene amination efficiency using ammonia. A tentative reaction mechanism was proposed involving the long-lived N2 (A3 (Formula presented.)) and N2+ species, as evidenced by the key intermediates detected. With a deeper mechanistic understanding and by further optimizing the plasma reactor, the realization of cost-effective electrical amination of benzene with N2 could become reality. ? 2022 Wiley-VCH GmbH.
Accession Number: 20221511963338
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Record 394 of
Title:Multi-aperture High Resolution Imaging Technology Based on Plastic Imaging Fiber Array
Author(s):Du, Xiaorui(1,2); Xu, Huangrong(2,3); Li, Wenlong(1,2); He, Zhengquan(1); Kong, Depeng(1)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 51 Issue: 9 DOI: 10.3788/gzxb20225109.0906003 Published: September 2022
Abstract:Imaging fiber plays an important role in medicine， industry， aerospace and other fields because of its excellent flexibility， especially in the application of optical fiber endoscope in medicine. Optical fiber image transmission system is usually composed of imaging objective， imaging fiber and image sensor.At present， the number of pixels in cameras can reach millions or even tens of millions， but the number of pixels in optical fibers is usually only a few hundred thousand.Therefore， the resolution of the system is limited by the resolution of the imaging fiber itself， and the imaging resolution of the whole system basically depends on the number of pixels that the imaging fiber can transmit. At present， the imaging fiber bundles on the market have either high resolution but small total cross-sectional area， or large cross sectional size but fiber diameter up to ten microns. This phenomenon results in insufficient pixels and small image area of high resolution image fiber， while large cross section can not reach high resolution due to technological limitations. To solve the problems， this paper proposes a multi-aperture high-resolution imaging technology based on imaging fiber array， which uses the imaging fiber array and image Mosaic technology to break through the bottleneck of improving pixel number. The number of pixels in the system can be increased by using high resolution and small cross section imaging fiber arrays. Combined with the characteristics of overlapping imaging of microlens array， the problem of information loss caused by direct imaging of imaging fiber array can be solved and the integrity of optical fiber array imaging can be realized.This method is expected to increase the number of pixels in optical fiber image transmission system to millions of order of magnitude and improve the resolution of the system. The imaging fiber is designed to be arranged 6×8， and the microlens array is designed based on the imaging fiber array. There are two groups of aspherical lenses made of PMMA material， and the imaging fiber array and the two groups of microlens arrays have uniform positions. Add a telecentric objective lens in front of the microlens array as the main lens of the image transmission system to solve the problem of complete overlap of adjacent subgraphs caused by direct imaging of the microlens array. The focal length of the lens is 10.1 mm， the aperture coefficient is 6.3， and the field Angle is 88°. The simulation results show that both the main lens and the microlens array can meet the performance requirements of the imaging fiber， and the object information can be successfully transmitted to the imaging fiber. The modulation transfer function value of the system can reach more than 0.5 at 50 lp/mm， without weakening the quality of the primary image， and meet the resolution requirements of the imaging fiber. Experimental results show that the system contains 400 000 effective pixels and the system resolution is 40 lp/mm.The image is clear and complete， which proves that the design of the imaging system has a good feasibility， and has an important practical reference significance for improving the resolution of the optical fiber image transmission system. ? 2022 Chinese Optical Society. All rights reserved.
Accession Number: 20224413024210
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Record 395 of
Title:Dark gap solitons in one-dimensional nonlinear periodic media with fourth-order dispersion
Author(s):Li, Jiawei(1,2,3); Zhang, Yanpeng(2); Zeng, Jianhua(1,3)
Source: Chaos, Solitons and Fractals Volume: 157 Issue: DOI: 10.1016/j.chaos.2022.111950 Published: April 2022
Abstract:The studies of solitons are usually confined to the models with normal two-order dispersion or diffraction; while recent theoretical predictions and experimental observations have confirmed the important role that the fourth-order dispersion played in, leading to the discovery of a new class of solitons—quartic solitons in fibers. We here theoretically consider the one-dimensional (1D) periodic nonlinear media with both second-order and fourth-order dispersions, and uncover numerically the existence, properties, and stabilities of dark gap solitons populated within the associated linear photonic band gaps. Such gaps, particularly, are affected drastically by normal or anomalous fourth-order dispersion; the dark gap solitons are always found to be unstable for the latter, and are robustly stable and have a wide stability region for the former case, verified by linear-stability analysis and direct perturbed simulations. The obtained results provide insights into physics of dark gap solitons in higher-order dispersion regime. ? 2022 Elsevier Ltd
Accession Number: 20221011751523
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Record 396 of
Title:3D Nonlinear Localized Gap Modes in Bose-Einstein Condensates Trapped by Optical Lattices and Space-Periodic Nonlinear Potentials
Author(s):Li, Jiawei(1,2,3); Zhang, Yanpeng(2); Zeng, Jianhua(1,3)
Source: Advanced Photonics Research Volume: 3 Issue: 7 DOI: 10.1002/adpr.202100288 Published: July 2022
Abstract:Optical lattices and Feshbach resonance management are two mighty and widely used techniques for studying, both experimentally and theoretically, various physical issues and the underlying nonlinear dynamics of Bose?Einstein condensates. Both techniques show great power for studying solitons of different types, and particularly, the former technique realizes the creation of 1D bright matter-wave gap solitons, whose formation and properties in multidimensional systems, however, are much less known. Herein, both techniques and study are combined, theoretically and numerically, the formation and dynamics of 3D nonlinear localized gap modes, including fundamental gap solitons and their higher-order ones as soliton clusters, as well as gap vortices with topological charge s = 1. The stability regions of all the localized gap modes are identified by means of direct perturbed numerical simulations, revealing important insights into soliton physics in multidimensional space. ? 2022 The Authors. Advanced Photonics Research published by Wiley-VCH GmbH.
Accession Number: 20233114473053
