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Record 445 of
Title:Research progress of tunable fiber light sources with wavelength near 1 μm
Author(s):Dang, Wen-Jia(1); Gao, Qi(2,3); Li, Zhe(2,3); Li, Gang(2,3)
Source: Chinese Optics Volume: 14 Issue: 5 DOI: 10.37188/CO.2021-0125 Published: September 2021
Abstract:Tunable fiber light sources with wavelength near 1 μm are widely used in optical fiber sensing, laser cooling, photochemical, spectroscopy and medical fields. They have thus become an area of focus in fiber light source research in recent years. The development history of fiber light sources with wavelength tuning ability is firstly summarized systematically. Then, their problems and possible solutions are analyzed. Finally, the future developments of tunable fiber light sources near 1 μm are prospected. ? 2021, China Science Publishing & Media LTD. All right reserved.
Accession Number: 20214411106031
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Record 446 of
Title:Progress of NUV and FUV MCP-based photon-counting imaging detectors
Author(s):Li, Shizhao(1); Liu, Yong-An(2); Sheng, Li-Zhi(2)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11915 Issue: DOI: 10.1117/12.2605898 Published: 2021
Abstract:Photon counting imaging technology has been widely used in nuclear radiation detection, space environment detection, astronomy observation, nuclear physics and ultra-weak bioluminescence. In this paper, the progress and parameters of NUV (160-320nm) and FUV (102-170nm) photon-counting imaging detectors were described. The NUV detector was developed based on a sealed MCP-image intensifier which comprises input window, photocathode, MCP stack, Ge-layer and its ceramic substrate. To maximize the quantum efficiency, a Cesium Telluride (Cs2Te) photocathode was adopted, which was deposited on input window and mounted close to the MCP. For the FUV detector, because of the lower cut-off wavelength, there are no suitable window materials in this band and the open-faced design should be used to meet the requirements of the detection. Therefore, a Cesium Iodide (CsI) photocathode deposited on the input surface of the MCP was used to optimize detector efficiency. By using an existing wedge and strip anode (WSA), the imaging performance of the NUV and FUV detectors was tested respectively. Experimental results show that the quantum efficiency of Cs2Te is 12.1% (at 230nm), the spatial resolution of NUV and FUV detectors is better than 70μm, the dark count rate of NUV and FUV detectors is about 10.5- A nd 2.3-counts/s?cm2 respectively. ? 2021 SPIE.
Accession Number: 20214611146508
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Record 447 of
Title:A Comprehensive Review on Parallel Phase-shifting Digital Holography(Invited)
Author(s):Zhang, Meiling(1); Gao, Peng(1); Wen, Kai(1); Zhuo, Kequn(1); Wang, Yang(1); Liu, Lixin(1); Min, Junwei(2); Yao, Baoli(2)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 50 Issue: 7 DOI: 10.3788/gzxb20215007.0709001 Published: July 25, 2021
Abstract:Phase-shifting Digital Holography(PSDH), which combines phase-shifting technology with digital holography, provides a fast, non-invasive, and high-precision approach for the three-dimensional morphology or refractive index distribution of microscopic objects. Compared with the off-axis digital holography, the phase-shifting on-axis digital holography makes full utilization of Spatial-bandwidth Product (SBP) of the CCD camera. The conventional phase-shifting digital holography needs to records multiple phase-shifting holograms in a step-by-step manner, from which the artifact-free phase and amplitude images of a sample can be reconstructed. To enhance the imaging speed of PSDH, parallel phase-shifting technique (or simultaneous phase-shifting technique) was proposed, with which multiple phase-shifting holograms can be obtained at the same time. In this paper, the concept and implementation of phase-shifting technologies are introduced firstly. Then, three different approaches of parallel phase-shifting, which are based on multiple CCDs, pixelated phase-mask, and parallel beam-splitting, are reviewed. Eventually, the applications of parallel PSDH in the biomedical field, air/liquid flow visualization, surface topography, micro-/nano-scale device inspection are introduced. ? 2021, Science Press. All right reserved.
Accession Number: 20213110707030
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Record 448 of
Title:Dual-wavelength in-line digital holography with untrained deep neural networks
Author(s):Bai, Chen(1); Peng, Tong(1,2); Min, Junwei(1); Li, Runze(1); Zhou, Yuan(1); Yao, Baoli(1,3)
Source: Photonics Research Volume: 9 Issue: 12 DOI: 10.1364/PRJ.441054 Published: December 1, 2021
Abstract:Dual-wavelength in-line digital holography (DIDH) is one of the popular methods for quantitative phase imaging of objects with non-contact and high-accuracy features. Two technical challenges in the reconstruction of these objects include suppressing the amplified noise and the twin-image that respectively originate from the phase difference and the phase-conjugated wavefronts. In contrast to the conventional methods, the deep learning network has become a powerful tool for estimating phase information in DIDH with the assistance of noise suppressing or twin-image removing ability. However, most of the current deep learning-based methods rely on supervised learning and training instances, thereby resulting in weakness when it comes to applying this training to practical imaging settings. In this paper, a new DIDH network (DIDH-Net) is proposed, which encapsulates the prior image information and the physical imaging process in an untrained deep neural network. The DIDHNet can effectively suppress the amplified noise and the twin-image of the DIDH simultaneously by automatically adjusting the weights of the network. The obtained results demonstrate that the proposed method with robust phase reconstruction is well suited to improve the imaging performance of DIDH. ? 2021 Chinese Laser Press.
Accession Number: 20220111429924
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Record 449 of
Title:Research progress of 0.9 ~ 1.0 μm near-infrared continuous-wave fiber lasers
Author(s):Dang, Wen-Jia(1); Li, Zhe(2,3); Lu, Na(1); Li, Yu-Ting(1); Zhang, Lei(1); Tian, Xiao(1)
Source: Chinese Optics Volume: 14 Issue: 2 DOI: 10.37188/CO.2020-0193 Published: March 2021
Abstract:Near-infrared continuous-wave fiber lasers with wavelengths of 0.9~1.0 μm have important application prospects in the fields of high-power blue and ultraviolet laser generation, high-power single-mode pump sources, biomedicine and lidars. They have thus become a heavily researched topic in recent years. At present, their gain mechanisms mainly include a rare earth ion gain or a nonlinear effect gain. In this paper, the research progress of 0.9~1.0 μm fiber lasers based on these two kinds of gain mechanisms are reviewed in detail, and the technical bottlenecks and solutions of these lasers are analyzed. Furthermore, the potential directions for the future of their research are proposed. Copyright ?2021 Chinese Optics. All rights reserved.
Accession Number: 20211610236249
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Record 450 of
Title:Physical characteristics and spillage detection Using multifeature fusion
Author(s):Liu, Caiyu(1); Zhou, Zuofeng(2); Wu, Qingquan(3)
Source: Journal of Physics: Conference Series Volume: 2083 Issue: 2 DOI: 10.1088/1742-6596/2083/2/022041 Published: December 2, 2021
Abstract:As an important part of road maintenance, the detection of road sprinkles has attracted extensive attention from scholars. However, after years of research, there are still some problems in the detection of road sprinkles. First of all, the detection accuracy of traditional detection algorithm is deficient. Second, deep learning approaches have great limitations for there are various kinds of sprinkles which makes it difficult to build a data set. In view of the above problems, this paper proposes a road sprinkling detection method based on multi-feature fusion. The characteristics of color, gradient, luminance and neighborhood information were considered in our method. Compared with other traditional methods, our method has higher detection accuracy. In addition, compared with deep learning-based methods, our approach doesn't involve creating a complex data set and reduces costs. The main contributions of this paper are as follows: I. For the first time, the density clustering algorithm is combined with the detection of sprinkles, which provides a new idea for this field. II. The use of multi-feature fusion improves the accuracy and robustness of the traditional method which makes the algorithm usable in many real-world scenarios. ? 2021 Institute of Physics Publishing. All rights reserved.
Accession Number: 20215111370190
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Record 451 of
Title:Standoff detection of explosive materials using time-gated UV-Raman spectroscopy
Author(s):Wang, Bo(1,2); Zhang, Pu(1); Zhang, Shuyao(3); Zhu, Xiangping(1); Zhao, Wei(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12064 Issue: DOI: 10.1117/12.2606981 Published: 2021
Abstract:Improvised explosive devices (IED) and homemade explosives (HMEs) have become the preferred choice for terrorists and insurgents. It's a challenge to develop the techniques to detect explosive hazards at standoff distances. In this paper, a standoff UV Raman spectrum detection system for explosive detection was developed, which can realize 2-10m Raman spectrum detection of solid, solution and trace potassium nitrate samples. The relationship between Raman signal intensity (RSI) and pulse energy, detection distance and sample concentration was studied. The experimental results show that the RSI is approximately proportional to the pluse energy and contains nonlinear terms. It has an inverse square relationship with the detection distance and a linear relationship with the sample concentration. The concentration of solution and trace potassium nitrate samples of were successfully predicted at 2m distance, and the root mean square error of prediction (RMSEP) was 11.7 and 6.1, respectively.A simple and effective method for preparing trace potassium nitrate is presented. Copyright ? 2021 SPIE.
Accession Number: 20220211450487
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Record 452 of
Title:CCD signal acquisition and optimal digital denoise technology
Author(s):Li, Wencan(1,2); Wen, Yan(1,3); Wang, Dong(1); Yao, Dalei(1)
Source: High Technology Letters Volume: 27 Issue: 4 DOI: 10.3772/j.issn.1006-6748.2021.04.011 Published: December 2021
Abstract:To reduce the charge-coupled device(CCD) readout noise and improve the detection ability under low illumination and dim targets, a new low-noise CCD signal processing technology-CCD digital denoise-is gradually being employed in aerospace detection and other fields. In this study, the main readout noise of CCD detectors and its characteristics are analyzed. A CCD digital denoise system and an experimental platform are designed as well as established by using a PCIe data acquisition card. According to the characteristics of readout noise, some digital filters are analyzed and designed based on distributed kernel coefficient, and the optimal kernel coefficients are obtained through iteration. Then, CCD signal and filter model are established, and the optimal filter is designed to apply to the digital denoise system. Finally, according to the image data obtained from the system, the performance of the digital denoise system and digital filtering algorithm is evaluated and compared. At 500kHz and 1MHz CCD readout rates, the denoising performance of the optimal filter designed in the experiment is 16%-32% higher than that of the digital filter with kernel distribution coefficient, and 50%-60% higher than that of the traditional correlated double sampling technology. Copyright ? by HIGH TECHNOLOGY LETTERS PRESS.
Accession Number: 20215211395539
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Record 453 of
Title:Molybdenum Carbide Buried in D-Shaped Fibers as a Novel Saturable Absorber Device for Ultrafast Photonics Applications
Author(s):Liu, Sicong(1); Shang, Shiguang(2); Lv, Ruidong(3); Wang, Yonggang(1,4); Wang, Jiang(1); Ren, Wei(2); Wang, Yishan(4)
Source: ACS Applied Materials and Interfaces Volume: 13 Issue: 16 DOI: 10.1021/acsami.1c01345 Published: April 28, 2021
Abstract:Study of nonlinear laser-matter interactions in 2D materials has promoted development of photonics applications. As a typical MXene material, molybdenum carbide (Mo2C) has attracted much attention because of its graphene-like structure. Here, a type of D-shaped fiber (DF)-buried Mo2C saturable absorber (SA) fabricated by magnetron-sputtering deposition (MSD) and sol-gel technique is reported. The Mo2C material was buried between the bottom DF and the upper amorphous silica fabricated by sol-gel technology. Therefore, the DF-based SA effectively solves the problem of material shedding and aging, thus improving the stability and damage threshold of the fiber laser. Application of the SA in erbium-doped fiber laser and stable passive Q-switched operation with a maximum pulse energy of 430.47 nJ is realized. By adjusting the polarization state and pump power, high-power mode-locked pulses are generated with a pulse duration and output power of 199 fs and 54.13 mW, respectively. Further, bound-state soliton pulses are obtained with a pulse width of 312 fs and soliton interval of 1.26 ps for the first time based on MXene materials. Moreover, by application of the SA in ytterbium-doped fiber lasers, a stable dissipative soliton mode-locked pulse is obtained with a pulse width of 23 ps. These results indicate that the DF-based buried Mo2C as a novel SA provides a reliable method for all-fiber and multifunctional high-power ultrafast laser. ? 2021 American Chemical Society.
Accession Number: 20211910310695
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Record 454 of
Title:X-ray communication experiment using photocathode X-ray tube
Author(s):Liu, Yong-An(1,2); Xuan, Hao(1,2); Sheng, Li-Zhi(1); Qiang, Peng-Fei(1); Su, Tong(1); Tian, Jin-Shou(1); Zhao, Bao-Sheng(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11763 Issue: DOI: 10.1117/12.2587619 Published: 2021
Abstract:In this paper, a novel X-ray tube, which uses a photocathode as an electron emission source, is first introduced. The X-ray tube with photocathode can use an external light source to control the output of photoelectrons, thereby controlling the characteristics of the emitted X-rays. Compared with the traditional X-ray tube with hot cathode, the X-ray emitted by the photocathode X-ray tube is completely modulated by the external light source. Therefore, X-rays can achieve instant on-off and arbitrary pulse waveform emission, and have extremely high time resolution. The basic characteristics of the photocathode X-ray tube was tested. By using the developed X-ray tube and LED light source, preliminary X-ray communication experiments have been carried out. The results show that the digital signal restoration with a frequency of up to 1MHz can be achieved. Except for X-ray communication, the developed photocathode X-ray tube can also have important applications in many fields such as radiation calibration and scintillator afterglow measurement. ? 2021 SPIE
Accession Number: 20211410162136
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Record 455 of
Title:Off-axis optical levitation and transverse spinning of metallic microparticles
Author(s):Liang, Yansheng(1); Yan, Shaohui(2); Wang, Zhaojun(1); Yao, Baoli(2); Lei, Ming(1)
Source: Photonics Research Volume: 11 Issue: 2144-2151 DOI: null Published:
Abstract:45
Accession Number: 20214411088663
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Record 456 of
Title:Difference curvature multidimensional network for hyperspectral image super-resolution
Author(s):Zhang, Chi(1); Zhang, Mingjin(1); Li, Yunsong(1); Gao, Xinbo(1,2); Shi, Qiu(3)
Source: Remote Sensing Volume: 17 Issue: DOI: 3455 Published:
Abstract:56
Accession Number: 20213610868178
