2021
2021
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Record 73 of
Title:On-chip generation and characterization of densely-spaced time-bin entangled qubits
Author(s):Yu, Hao(1,2); Chemnitz, Mario(1); Sciara, Stefania(1); Fischer, Bennet(1); Crockett, Benjamin(1); Roztocki, Piotr(1); Little, Brent E.(2); Chu, Sai T.(3); Moss, David J.(4); Aza?a, José(5); Wang, Zhiming(2); Morandotti, Roberto(1,2)Source: Optics InfoBase Conference Papers Volume: Issue: DOI: null Published: 2021Abstract:By using an on-chip unbalanced interferometer for densely-spaced time-bin state preparation/processing and a spiral waveguide for photon-pair generation, we demonstrate and implement high-quality densely-spaced time-entangled two-photon qubits. ? 2021 OSA - The Optical Society. All rights reserved.Accession Number: 20214911288206 -
Record 74 of
Title:Effective strategy to achieve a metal surface with ultralow reflectivity by femtosecond laser fabrication
Author(s):Li, Xun(1,2); Li, Ming(1); Liu, Hongjun(1,3)Source: Chinese Optics Letters Volume: 9 Issue: 5 DOI: 10.3788/COL202119.051401 Published: April 10, 2021Abstract:An effective and simple method is proposed for fabricating the micro/nano hybrid structures on metal surfaces by adjusting femtosecond laser fluence, scanning interval, and polarization. The evolution of surface morphology with the micro/nano structures is discussed in detail. Also, the mechanism of light absorption by the micro/nano hybrid structures is revealed. Compared with the typical periodic light-absorbing structures, this type of micro/nano hybrid structures has an ultralow average reflectivity of 2% in the 250–2300 nm spectral band and the minimum 1.5% reflectivity in UV band. By employing this method, large areas of the micro/nano hybrid structures with high consistency could be achieved. ? 2021 Chinese Optics LettersAccession Number: 20212010346866 -
Record 75 of
Title:Accelerating patch-based low-rank image restoration using kd-forest and Lanczos approximation
Author(s):Guo, Qiang(1,2); Zhang, Yongxia(1,2); Qiu, Shi(3); Zhang, Caiming(4)Source: Information Sciences Volume: 556 Issue: DOI: 10.1016/j.ins.2020.12.066 Published: May 2021Abstract:Patch-based low-rank approximation (PLRA) via truncated singular value decomposition is a powerful and effective tool for recovering the underlying low-rank structure in images. Generally, it first performs an approximate nearest neighbors (ANN) search algorithm to group similar patches into a collection of matrices with reshaping them as vectors. The inherent correlation among similar patches makes these matrices have a low-rank structure. Then the singular value decomposition (SVD) is used to derive a low-rank approximation of each matrix by truncating small singular values. However, the conventional implementation of patch-based low-rank image restoration suffers from high computational cost of the ANN search and full SVD. To address this limitation, we propose a fast approximation method that accelerates the computation of PLRA using multiple kd-trees and Lanczos approximation. The basic idea of this method is to exploit an index kd-tree built from patch samples of the observed image and several small kd-trees built from overlapping regions of the image to accelerate the search for similar patches, and apply the Lanczos bidiagonalization procedure to obtain a fast low-rank approximation of patch matrix without computing the full SVD. Experimental results on image denoising and inpainting tasks demonstrate the efficiency and accuracy of our method. ? 2020 Elsevier Inc.Accession Number: 20210309774632 -
Record 76 of
Title:Non-Invasive Measurement for Cardiac Variations Using a Fiber Optic Sensor
Author(s):Lyu, Weimin(1); Xu, Wei(2,3); Yang, Fangang(4); Chen, Shuyang(5); Tan, Fengze(1); Yu, Changyuan(5)Source: IEEE Photonics Technology Letters Volume: 33 Issue: 18 DOI: 10.1109/LPT.2021.3078757 Published: September 15, 2021Abstract:Cardiovascular diseases (CVDs) are very common in modern society, such as atherosclerosis, hypertension, etc., which have a great impact on heart function. Therefore, hospitalization monitoring alone is far from enough. Long-term monitoring of the heart is needed in daily life. The technology of non-invasive monitoring of the cardiovascular system can meet the needs of long-term monitoring of the heart condition, helping to promote the improvement of lifestyle and daily care, reducing the overall risk of developing CVDs. The purpose of this study is to investigate the cardiac response after different exercises using a 3\times 3 demodulation scheme-based ballistocardiography (BCG) monitoring system. A fiber optic sensor (FOS)-based smart cushion is used to replace the traditional inconvenient electrocardiogram (ECG) for heart rate variability (HRV). The correlation between BCG inter-beat interval (IBI) and ECG IBI is 0.9862, and the RMSE is 0.0139. The BCG signal can assess cardiac contractility by analyzing RJ interval with ECG, which is a practical alternative to the pre-ejection period (PEP). ? 1989-2012 IEEE.Accession Number: 20212010370841 -
Record 77 of
Title:Design and characterization of a thermally stabilized fiber Fabry-Perot etalon as a wavelength calibrator for high-precision spectroscopy
Author(s):Tang, Liang(1,2); Ye, Huiqi(1,2); Hao, Jun(1,2,3); Wei, Ruyi(4); Xiao, Dong(1,2)Source: Applied Optics Volume: 60 Issue: 19 DOI: 10.1364/AO.417586 Published: July 1, 2021Abstract:Filtering light from a broadband source with a Fabry-Perot etalon generates comb-like peaks in the spectral domain that can serve as calibration reference for precise Doppler shift detection on astronomical spectrographs. Fiber Fabry-Perot etalons are small in size and easily aligned optically. In application, high thermal sensitivity of the fiber core material requires a highly stable temperature control system. Here, we report on the design, characterization, and thermal performance of a fiber Fabry-Perot etalon-based calibrator system insensitive to environmental temperature perturbation, aimed as a reference for m s-1 precision radial velocity measurements. A fast and simple method to estimate the etalon finesse and a dual-loop approach to achieve sub-millikelvin temperature fluctuation are proposed and demonstrated. ? 2021 Optical Society of America.Accession Number: 20212310467002 -
Record 78 of
Title:Verification study for the mineral and rock identification using multispectral camera of the "Zhurong" Mars Rover on the earth
Author(s):Xie, Juan(1,2,3); Yan, Kai(1,2,3); Kang, Zhizhong(1,2,3); Xu, Xiaojian(1,2,3); Xue, Bin(4); Yang, Jianfeng(4); Tao, Jinyou(4)Source: National Remote Sensing Bulletin Volume: 25 Issue: 7 DOI: 10.11834/jrs.20211065 Published: July 25, 2021Abstract:China's first autonomous Mars exploration mission probe "Tianwen-1" was successfully launched in July 2020, and the rover of "Tianwen-1" successfully landed on the pre-selected landing area in the southern Utopia Plain of Mars on May 15. After landing on Mars, China's first Mars rover "Zhurong" will carry out inspections and bring the raw scientific data for Chinese Mars exploration. The multispectral camera mounted on the "Zhurong" rover can be used to study the types of mineral and rock near the landing area. Identifying the types of mineral and rock on Mars is of great significance for understanding the Martian atmospheric change, environmental conditions, geological evolution, and future livability. The study in this article selected 18 kinds of common mineral and rock on the surface of Mars, and shot these mineral and rock with the same multispectral camera as on "Zhurong" rover in the earth environment. Then, this study uses the obtained multispectral image carry out the research of mineral and rock identification, hoping to provide guidance for future in-situ identification of mineral and rock on the surface of Mars based on the "Zhurong" multispectral camera data. Considering that 8-band spectral data is not enough to capture the spectral characteristics of all mineral and rock, it will result in fewer mineral and rock identified, this paper uses color features to assist in the identification of mineral and rock. This paper uses band operation based on multispectral image and HSV color feature histogram extraction based on color image to identify different types of mineral and rock. The above method can identify different types of mineral and rock from the perspective of multispectral features and color features. This study collected multispectral images of mineral and rock under three different shooting conditions, and found that the spectral characteristics of mineral and rock may change under different shooting conditions, which will have an impact on mineral and rock identification. The multispectral image data used in this paper was collected under the conditions of the solar elevation angle at about 60 °, the shooting height at 1.8 meters and the shooting angle at about 37°. Under this condition, the research method in this paper has extracted identification indexes of 12 kinds of mineral and rock. The identification indexes corresponding to specific mineral and rock are listed in the article, all results are based on the above shooting condition. The study shows that: using the band operation based on multispectral image, mineral and rock with prominent spectral characteristics under 8 specific bands can be identified; and using color feature histogram extracted from HSV color image, mineral and rock with a relatively concentrated color feature can be identified. In addition, since different shooting conditions will have an impact on the identification of mineral and rock, it is necessary to do the identification research under different conditions in the future. ? 2021, Science Press. All right reserved.Accession Number: 20213210735699 -
Record 79 of
Title:A Deformable Convolutional Neural Network with Oriented Response for Fine-Grained Visual Classification
Author(s):Ruan, Shangxian(1); Yang, Jiating(2); Chen, Jianbo(3)Source: ACM International Conference Proceeding Series Volume: Issue: DOI: 10.1145/3457682.3457702 Published: February 26, 2021Abstract:Fine-grained visual classification (FGVC) aims to classify images belonging to the same basic category in a more detailed sub-category. It is a challenging research topic in the field of computer vision and pattern recognition in recent years. The existing FGVC method conduct the task by considering the part detection of the object in the image and its variants, which rarely pays attention to the difference in expression of many changes such as object size, posture, and perspective. As a result, these methods generally face two major difficulties: 1) How to effectively pay attention to the latent semantic region, and reduce the interference caused by many changes in pose and perspective; 2) How to extract rich feature information for non-rigid and weak structure objects. In order to solve these two problems, this paper proposes a deformable convolutional neural network with oriented response for FGVC. The proposed method can be divided into three main steps: firstly, the local region of latent semantic information is localized based on a lightweight CAM network; then, the deformable convolutional ResNet-50 network and the rotation-invariant coding oriented response network are designed, which input the original image and local region into the feature network to learn the discriminant features of rotation invariance; finally, the learned features are embed into a joint loss to optimize the entire network end-to-end. Experiments are carried out on three challenging FGVC datasets, including CUB-200-2011, FGVC_Aircraft and Aircraft_2 datasets. The results show that the accuracy of the proposed method on all datasets is better than the comparison method, which can effectively improve the accuracy of weakly supervised FGVC. ? 2021 ACM.Accession Number: 20212810613369 -
Record 80 of
Title:Near-infrared image recovery based on modulation instability in CdZnTe:V
Author(s):Liao, Yuan(1,2); Wang, Zhaolu(1); Huang, Nan(1); Liu, Hongjun(1,3)Source: Optics Express Volume: 29 Issue: 20 DOI: 10.1364/OE.438061 Published: September 27, 2021Abstract:We propose a near-infrared image recovery method based on modulation instability in the photorefractive semiconductor CdZnTe:V. The formation mechanism of modulation instability in CdZnTe:V is discussed, and the theoretical gain model is derived. Theoretical results of optical image recovery at 1 μm and 1.5 μm wavelengths demonstrate that the maximum cross-correlation gain is 2.6 with a signal to noise intensity ratio of 0.1. These results suggest that our method could be one of potential aids for near-infrared imaging. ? 2021 Optical Society of America under the terms of the OSA Open Access Publishing AgreementAccession Number: 20213810904182 -
Record 81 of
Title:Experimental Demonstration of Nonlinear Scattering Processes in a Microbottle Resonator Based on a Robust Packaged Platform
Author(s):Wang, Mengyu(1); Yang, Yu(2); Lu, Zhizhou(3); Wang, Weiqiang(3); Zhang, Wenfu(3); Xie, Chengfeng(1); Zhong, Huikai(1); Wu, Lingfeng(1); Wu, Tao(1); Tan, Qinggui(4); Fu, Yanjun(1); Wang, Keyi(2)Source: Journal of Lightwave Technology Volume: 39 Issue: 18 DOI: 10.1109/JLT.2021.3092636 Published: September 15, 2021Abstract:Microbottle resonators (MBR) have attracted research interest for studying nonlinear optical interactions in last two decades, due to the ultra-tight optical confinement in spaces of three dimensions. In this paper, silica MBRs exhibiting rich resonant modes with ultra-high quality factor up to 3.73 \times {10^8} are demonstrated, based on which a portable and robust packaged platform with a tapered fiber coupling is established. Such a packaged platform effectively avoids external perturbations such as air flow and tiny mechanical vibrations, which supports our experimental demonstration of nonlinear scattering effects including four-wave mixing (FWM), simulated Raman scattering, and simulated Brillouin scattering. As a result, Raman-assisted FWM and Brillouin-assisted FWM are observed due to the strong field enhancement in the MBR. In a further investigation, a Kerr frequency comb with broad bandwidth of ～200 nm and a Raman-assisted comb with a bandwidth up to ～50 nm is achieved, correspondingly. Our works show the versatility of MBR for fundamental research and may open a new route to the development of practical applications in frequency conversion, spectroscopy and communications. ? 1983-2012 IEEE.Accession Number: 20213310777740 -
Record 82 of
Title:Influence of Channel Center Wavelength Shift of the Hyperspectral Remote Sensor on Red Edge Spectra
Author(s):Zhang, Yaqiong(1); Zhang, Wenjuan(2); Chen, Zhengchao(2); Li, Haiwei(3)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 41 Issue: 14 DOI: 10.3788/AOS202141.1428003 Published: July 25, 2021Abstract:We simulated the reflectance of typical vegetation in the red-edge region before and after the channel center wavelength shift of hyperspectral remote sensors to quantitatively examine the effect of the channel center wavelength shift on the red edge spectra. The results show that the channel center wavelength shift leads to many "spike" and "shake" phenomena in the reflectance curves of the red-edge region, and the reflectance curves in the region without characteristic absorption become unsmooth. Moreover, there is a significant linear relationship between the channel center wavelength shift and the red edge position (REP) error (coefficient of determination R2=0.99). For a 10 nm hyperspectral remote sensor, when the channel center wavelength shifts are 1 nm, 3 nm, and 5 nm, the maximum errors in red-edge reflectance are 1.46%, 4.49%, and 9.57%, respectively, and the red edge spectra have the obvious "blue shift" phenomenon, with the REP shifting by 0.75 nm, 2.60 nm, and 5.52 nm, respectively. The channel center wavelength shift will lead to the pseudo-shift of the red edge or cause the "covering" or "strengthening" effect on the red edge shift induced by vegetation stress, which will directly affect the monitoring accuracy of vegetation stress based on hyperspectral remote sensing data. Channel center wavelength shift is an important source of the red edge shift. Accurate spectral calibration is the important basis of quantitative application related to the red edge spectra of vegetation. ? 2021, Chinese Lasers Press. All right reserved.Accession Number: 20213410810670 -
Record 83 of
Title:Emergence of Laser Cavity-Solitons in a Microresonator-Filtered Fiber Laser
Author(s):Rowley, Maxwell(1); Hanzard, Pierre-Henry(1); Cutrona, Antonio(1); Chu, Sai T.(2); Little, Brent E.(3); Morandotti, Roberto(4,5); Moss, David J.(6); Gongora, Juan Sebastian Totero(1); Peccianti, Marco(1); Pasquazi, Alessia(1)Source: 2021 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2021 Volume: Issue: DOI: 10.1109/CLEO/Europe-EQEC52157.2021.9542409 Published: June 2021Abstract:In an open nonlinear system, emergent complex structures are generally determined by a set of global parameters. Cavity-solitons are an example of such structures and, in their temporal form, have seeded the last decade of major developments in microresonator-based optical frequency combs. These optical pulses typically require complex procedures and external feedback to be induced and maintained. Recent progress has seen the microresonators directly embedded into a laser cavity [1] , [2] where it is possible to simply initiate cavity-soliton formation by increasing the laser-diode driving current [3]. Hybrid laser-microresonator schemes have been considered since 2012 [4] , and extremely efficient laser cavity-solitons have been experimentally and theoretically demonstrated in a laser microcomb [5]. ? 2021 IEEE.Accession Number: 20214311063944 -
Record 84 of
Title:Emergence of laser cavity-solitons in a microresonator-filtered fiber laser
Author(s):Rowley, Maxwell(1); Hanzard, Pierre Henry(1); Cutrona, Antonio(1); Chu, Sai T.(2); Little, Brent E.(3); Morandotti, Roberto(4,5); Moss, David J.(6); Gongora, Juan Sebastian Totero(1); Peccianti, Marco(1); Pasquazi, Alessia(1)Source: Optics InfoBase Conference Papers Volume: Issue: DOI: null Published: 2021Abstract:The parameter space, defined by simple global controls, is probed in a microresonator-filtered fiber laser. We identify a distinct region that clearly admits solitons and we investigate the role of slow nonlinearities in their emergence. ? OSA 2021, ? 2021 The Author(s)Accession Number: 20214811251396