2017
2017
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Record 265 of
Title:High power vertical stacked diode laser development using macro-channel water cooling and hard solder bonding technology
Author(s):Yu, Dongshan(1); Liang, Xuejie(1); Wang, Jingwei(1); Li, Xiaoning(1); Nie, Zhiqiang(2); Liu, Xingsheng(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10123 Issue: DOI: 10.1117/12.2250692 Published: 2017Abstract:A novel marco channel cooler (MaCC) has been developed for packaging high power diode vertical stacked (HPDL) lasers, which eliminates many of the issues in commercially-available copper micro-channel coolers (MCC). The MaCC coolers, which do not require deionized water as coolant, were carefully designed for compact size and superior thermal dissipation capability. Indium-free packaging technology was adopted throughout product design and fabrication process to minimize the risk of solder electromigration and thermal fatigue at high current density and long pulse width under QCW operation. Single MaCC unit with peak output power of up to 700W/bar at pulse width in microsecond range and 200W/bar at pulse width in millisecond range has been recorded. Characteristic comparison on thermal resistivity, spectrum, near filed and lifetime have been conducted between a MaCC product and its counterpart MCC product. QCW lifetime test (30ms 10Hz, 30% duty cycle) has also been conducted with distilled water as coolant. A vertical 40-MaCC stack product has been fabricated, total output power of 9 kilowatts has been recorded under QCW mode (3ms, 30Hz, 9% duty cycle). ? 2017 SPIE.Accession Number: 20172403752852 -
Record 266 of
Title:Observation of particle manipulation with axial plane optical microscopy
Author(s):An, Sha(1,2); Peng, Tong(1,2); Zhou, Xing(1,2); Han, Guo-Xia(1); Huang, Zhang-Xiang(1); Yu, Xiang-Hua(1); Cai, Ya-Nan(1,2); Yao, Bao-Li(1); Zhang, Peng(1)Source: Wuli Xuebao/Acta Physica Sinica Volume: 66 Issue: 1 DOI: 10.7498/aps.66.010702 Published: January 5, 2017Abstract:Optical micromanipulation of particles based on the optical trapping effect induced by the interaction between light and particles has been successfully applied to many interdisciplinary fields including biomedicine and material sciences. When particles are trapped in three dimensions, the conventional wide-field optical microscopy can only monitor the movement of the trapped particles in a certain transverse plane. The ability to observe the particle movement along light trajectories is limited. Recently, a novel method named axial plane optical microscopy (APOM) has been developed to directly image the axial plane that is parallel to the optical axis of an objective lens. The APOM observes the axial plane by converting the axial information of a sample into that of a transverse plane by using a 45°-tilted mirror. In this paper, we propose and demonstrate that the APOM serves as an effective tool for observing the axial movement of particles in optical tweezers. By combining with a conventional wide-field optical microscopy, we show that both transverse and axial information can be acquired simultaneously for the optical micromanipulation. As in our first experimental demonstration, we observe two particles which are trapped and aligned along the optical axis. From the transverse image, only one particle is observable, and it is difficult to obtain the information along the axial direction. However, in the axial plane imaging, the longitudinal dipolar structure formed by the two particles is clearly visible. This clearly demonstrates the APOM imaging capability along the axial axis. The numerically simulations on the trapping focal spot against the position of a collimating lens agree well with our experimental APOM results. Furthermore, we directly observe the dynamic capture process of a single trapped particle in transverse plane by conventional wide-field optical microscopy as well in axial plane by the APOM, and can obtain the 3D information rapidly and simultaneously. We point out that the observable axial dynamic range is about 30 μm. Taking advantages of no requirement of scanning and data reconstruction, the APOM has potential applications in many fields, including optical trapping with novel beams and 3D imaging of thick biological specimens. ? 2017 Chinese Physical Society.Accession Number: 20170603332788 -
Record 267 of
Title:4.62 kW excellent beam quality laser output with a low-loss Yb/Ce co-doped fiber fabricated by chelate gas phase deposition technique
Author(s):Zheng, Jinkun(1,2); Zhao, Wei(1); Zhao, Baoyin(1); Hou, Chaoqi(1); Li, Zhe(1); Li, Gang(1); Gao, Qi(1); Ju, Pei(1); Gao, Wei(1); She, Shengfei(1); Wu, Peng(2); Li, Weinan(1)Source: Optical Materials Express Volume: 7 Issue: 4 DOI: 10.1364/OME.7.001259 Published: 2017Abstract:A high-power Yb/Ce co-doped double-clad fiber with low optical loss was successfully fabricated by an optimized chelate gas phase deposition technique. It exhibits a nearly homogenous distribution of Al, Ce and Yb ions in the fiber core region, which reduce the clustering. The core attenuation at 1080 nm and 1383 nm are 12 dB/km and 46 dB/km, respectively, indicating high optical performance with a low optical loss. The amplifier stage with this fiber delivers 4.62 kW excellent beam quality (M2 = 1.67) laser output with a slope efficiency of 80.3%. The experimental results show that the chelate gas phase deposition technique is a prospective method to fabricate a Yb/Ce co-doped fiber with low optical loss, which is beneficial for acquiring multi-kilowatt continuous-wave fiber laser with excellent beam quality. ? 2017 Optical Society of America.Accession Number: 20171103452502 -
Record 268 of
Title:Photon-limited depth and reflectivity imaging with sparsity regularization
Author(s):Yan, Kang(1,2); Lifei, Li(1); Xuejie, Duan(3); Tongyi, Zhang(1); Dongjian, Li(1); Wei, Zhao(1)Source: Optics Communications Volume: 392 Issue: DOI: 10.1016/j.optcom.2017.01.032 Published: June 1, 2017Abstract:We demonstrate a depth and reflectivity imaging system at low light level based on sparsity regularization method. Depth and reflectivity imaging from the time-correlated single photon counting (TCSPC) measurement in limit of few photon counts are reconstructed through exploiting transform-domain sparsity. Two different sparsity-based penalty function: total variation (TV) penalty and l1 norm penalty measuring sparsity in the discrete cosine transform(DCT) basis, are applied to the experimental data. The results show that compared with traditional image denoising method, sparsity regularization approach achieves better accuracy with fewer photon measurements. Further more, the performance of TV regularization is proved better than l1-DCT regularization method for photon-limited imaging at first time, especially in the case of depth imaging. Our system is a photon-limited imaging device for a variety of applications, such as target detection, space surveillance, and distance measurement. ? 2017 Elsevier B.V.Accession Number: 20170503306534 -
Record 269 of
Title:Study on Position-Sensitive Anode in Photon Counting Imaging Detector
Author(s):Liu, Yongan(1,2); Li, Linsen(1,2); Liu, Zhe(1); Qiang, Pengfei(1,2); Liu, Duo(1,2); Sheng, Lizhi(1); Tian, Jinshou(1); Zhao, Baosheng(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 37 Issue: 4 DOI: 10.3788/AOS201737.0404001 Published: April 10, 2017Abstract:Wedge and strip anode(WSA) is one of charge division anodes. In the photon counting imaging detector, the role of the WSA is to decode the incident position of photon events. The anode performance parameters have an important influence on the imaging performance of the detector. The inter-electrode capacitance of WSA is studied, and its calculation formula is obtained by the theoretical model. The WSA panel with different parameters is designed and prepared. The relationship between cycle length, insulation gap width, anode collecting area, substrate material and the anode inter-electrode capacitance is analyzed. Test results show that the inter-electrode capacitance is in accordance with the theoretical calculation result and the deviation between calculated value and test value is within 10%. ? 2017, Chinese Lasers Press. All right reserved.Accession Number: 20172003665158 -
Record 270 of
Title:A General Framework for Edited Video and Raw Video Summarization
Author(s):Li, Xuelong(1); Zhao, Bin(2); Lu, Xiaoqiang(1)Source: IEEE Transactions on Image Processing Volume: 26 Issue: 8 DOI: 10.1109/TIP.2017.2695887 Published: August 2017Abstract:In this paper, we build a general summarization framework for both of edited video and raw video summarization. Overall, our work can be divided into three folds. 1) Four models are designed to capture the properties of video summaries, i.e., containing important people and objects (importance), representative to the video content (representativeness), no similar key-shots (diversity), and smoothness of the storyline (storyness). Specifically, these models are applicable to both edited videos and raw videos. 2) A comprehensive score function is built with the weighted combination of the aforementioned four models. Note that the weights of the four models in the score function, denoted as property-weight, are learned in a supervised manner. Besides, the property-weights are learned for edited videos and raw videos, respectively. 3) The training set is constructed with both edited videos and raw videos in order to make up the lack of training data. Particularly, each training video is equipped with a pair of mixing-coefficients, which can reduce the structure mess in the training set caused by the rough mixture. We test our framework on three data sets, including edited videos, short raw videos, and long raw videos. Experimental results have verified the effectiveness of the proposed framework. ? 1992-2012 IEEE.Accession Number: 20172403788917 -
Record 271 of
Title:Optimization of microchannel cooler of high power diode laser array package
Author(s):Wu, Dihai(1,3); Zhang, Pu(1); Nie, Zhiqiang(1); Liang, Xuejie(2); Wang, Jingwei(2); Liu, Xingsheng(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10085 Issue: DOI: 10.1117/12.2255693 Published: 2017Abstract:High power diode laser arrays have found increasing applications in the field of pumping solid-state lasers and fiber lasers. Due to the thermal crosstalk across diode laser arrays and non-uniformity of local flow rate within microchannel cooler, junction temperature distribution becomes inhomogeneous, consequently leading to spectrum broadening and large beam divergence of diode laser pumping sources. In this work, an analytical method and numerical heat transfer based on finite volume method were employed to optimize the inner structure of microchannel cooler so as to obtain low thermal resistance and uniform junction temperature distribution for the diode laser arrays. Three-dimensional numerical models were developed to study the fluid flow and heat transfer of copper stacked microchannel coolers with different dimensions and arrangements of inner channels and fins. More uniform junction temperature distribution of diode laser array package could be achieved by self-heating compensation with specific coolant covering width. These results could provide significant guidance for the design of microchannel coolers of high power diode laser arrays for better performance. ? 2017 SPIE.Accession Number: 20172103685893 -
Record 272 of
Title:Resonance spiking by periodic loss in the double-sided liquid cooling disk oscillator
Author(s):Nie, Rongzhi(1,2); She, Jiangbo(1); Li, Dongdong(4); Li, Fuli(2); Peng, Bo(1,3)Source: Laser Physics Volume: 27 Issue: 3 DOI: 10.1088/1555-6611/aa5c10 Published: March 2017Abstract:A double-sided liquid cooling Nd:YAG disk oscillator working at a pump repetition rate of 20 Hz is demonstrated. The output energy of 376 mJ is realized, corresponding to the optical-optical efficiency of 12.8% and the slope efficiency of 14%. The pump pulse width is 300 μs and the laser pulse width is 260 μs. Instead of being a damped signal, the output of laser comprises undamped spikes. A periodic intra-cavity loss was found by numerical analysis, which has a frequency component near the eigen frequency of the relaxation oscillation. Resonance effect will induce amplified spikes even though the loss fluctuates in a small range. The Shark-Hartmann sensor was used to investigate the wavefront aberration induced by turbulent flow and temperature gradient. According to the wavefront and fluid mechanics analysis, it is considered that the periodic intra-cavity loss can be attributed to turbulent flow and temperature gradient. ? 2017 Astro Ltd.Accession Number: 20170803363276 -
Record 273 of
Title:Single Image super-resolution restoration algorithm from external example to internal self-similarity
Author(s):Zheng, Xiangtao(1,2); Yuan, Yuan(1); Lu, Xiaoqiang(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 37 Issue: 3 DOI: 10.3788/AOS201737.0318006 Published: March 10, 2017Abstract:Single image super-resolution (SR) restoration is an ill-posed inverse problem, in which regularization restriction is done with image priori knowledge. One single image SR method is proposed which simultaneously taking external example and internal self-similarity into account. Here the external knowledge is learned by convolutional neural network from external low-resolution-high-resolution image pairs, while the internal prior is utilized by cluster and low-rank approximation. The experimental results show that the proposed method outperforms many other existing super-resolution methods in recovery effect and robustness. ? 2017, Chinese Lasers Press. All right reserved.Accession Number: 20171603576228 -
Record 274 of
Title:Effects of doping B2O3 on the defects-state in SiO2-containing phosphate based glasses
Author(s):He, Quanlong(1,2); Wang, Pengfei(1); Sun, Mengya(1,2); Lu, Min(1); Peng, And Bo(1)Source: Optical Materials Express Volume: 7 Issue: 8 DOI: 10.1364/OME.7.002697 Published: 2017Abstract:The effects of doping B2O3 on the defects and their induced anti-radiation performance change of the multicomponent phosphate glasses were studied in this work. The introduction of B2O3 reduces the connectivity of phosphate chains and thus increases the concentration of PO3-EC and PO4-EC defects in the phosphate glass network that have large absorption in the high-energy region. Meanwhile, B2O3 can improve the oxidizability of those glasses at the same melting temperature under which Fe2+ ions will be more easily oxidized to Fe3+ ions. However, the addition of B2O3 in terms of H3BO3, as it reaches up to 7.5 wt%, could enhance the gamma radiation resistance of the phosphate glasses, in this case B2O3, and enter the phosphate glass network in the form of B5O8 units. The units enhanced the connectivity of the long phosphate chains, and thus reduced the concentration of PO3-EC and PO4-EC defects in phosphate glasses. ? 2017 Optical Society of America.Accession Number: 20172803941563 -
Record 275 of
Title:Significant improvement of gamma radiation resistance in CeO2 doped phosphate glass by co-doping with Sb2O3
Author(s):He, Quanlong(1,2); Wang, Pengfei(1); Sun, Mengya(1,2); Lu, Min(1); Peng, Bo(1)Source: Optical Materials Express Volume: 7 Issue: 3 DOI: 10.1364/OME.7.001113 Published: March 1, 2017Abstract:We show that the gamma radiation resistances of new type of phosphate glass can be greatly improved by CeO2 and Sb2O3 co-doping. With the doping of CeO2, the radiation resistance (transmittance decrease ratio) is improved from 57.39% to 73.9% at 525 nm, and from 56.4% to 61.9% at 385 nm, respectively, when optical glasses were exposed to the gamma radiation with the dose of 250 krad (Si). It further increases to 92.4% at 525 nm by co-doping with Sb2O3, meanwhile, the induced optical losses were distinctly restrained at 1064 nm and 1550 nm, which shows potential applications in the fields of space-born star camera systems, laser window optics, fiber gyroscopes and communications. ? 2017 Optical Society of America.Accession Number: 20171003409222 -
Record 276 of
Title:Ti:Sapphire Femtosecond Pulses Pumped Directly by Green Diode Lasers
Author(s):Wang, Xianglin(1,2); Hu, Xiaohong(1,2); Xu, Peng(1); Zhang, Wei(1); Yang, Zhi(1); Wang, Yishan(1)Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 44 Issue: 7 DOI: 10.3788/CJL201744.0701002 Published: July 10, 2017Abstract:The laser beams emitted from a pair of 520 nm/1.45 W green diode lasers are shaped and focused on a Ti:sapphire laser crystal to complete the pumping process. The intracavity dispersion is compensated by using the GTI (Gires-Tournois interferometer) mirrors. The stable Kerr-lens mode locking state is achieved with an output pulse width of 91 fs, an output power of 208 mW, and a single pulse energy of 1.59 nJ. The narrowest pulse width of 82 fs is further realized after the optimization of cavity-type parameters and the maximum output power reaches 232 mW when the cavity length is shortened. ? 2017, Chinese Lasers Press. All right reserved.Accession Number: 20173704143891