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Efficient corner-pumped Nd:YAG/YAG composite slab laser

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Chinese Physics B 2010年第5期19卷 327-331页

作者：刘欢巩马理 Center for Photonics and Electronics Department of Precision Instruments and MechanologyTsinghua University

A corner-pumped type is a new pumping type in the diode-pumped all-solid-state lasers, which has the advantages of high pump efficiency and favourable pump uniformity. A highly efficient corner-pumped Nd：YAG/YAG composite slab laser is demonstrated in this paper. The maximal continuous-wave output power of the 1064 nm laser is up to 18.57 W with a slope efficiency and an optical-to-optical conversion efficiency of 44.9% and 39.8%, respectively. Inserting an acousto-optic Q-switch in the cavity, the highest average output power of the quasi-continuous wave 1064 nm laser of 6.73W is obtained at a repetition rate of 9.26 kHz. The experimental results show that a corner-pumped type is a kind of feasible schedules in the design of diode-pumped all-solid-state lasers with low or medium output powers.

关键词： corner-pumped Nd:YAG crystal continuous wave acousto-optic Q-switch

Wavefront Shaping for Fast Focusing Light through Scattering Media Based on Parallel Wavefront Optimization and Superpixel Method

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Chinese Physics Letters 2020年第2期37卷 25-29页

作者： Yingchun Ding Xinjing Lv Youquan Jia Bin Zhang Zhaoyang Chen Qiang Liu College of Mathematics and Physics Beijing University of Chemical TechnologyBeijing 100029 State Key Laboratory of Precision Measurement Technology and instruments Department of Precision InstrumentsTsinghua UniversityBeijing 100084

When light travels in biological tissues,it undergoes multiple scattering and forms speckles,which seriously restricts the penetration depth of optical imaging in biological *** wavefront shaping method,by modulating the wavefront of incident light to compensate for the wavefront aberration,light focusing and scanning imaging through scattering media can be ***,wavefront shaping must be accomplished within the speckle decorrelation *** the short speckle decorrelation time of living tissues,the speed of wavefront shaping is rather *** propose a new iterative optimization wavefront shaping method to improve the speed of wavefront shaping in which the existing parallel optimization wavefront shaping method is improved and is combined with the superpixel *** with the traditional multi-frequency parallel optimization method,the modulation rate of our method is ***,we combine the high frame rate amplitude modulator,i.e.,the digital micromirror device(DMD),with the superpixel method to replace the traditional phase modulator(i.e.,spatial light modulator),which further increases the optimization *** our experiment,when the number of the optical modes is 400,light focusing is achieved with only 1000 DMD superpixel masks and the enhancement factor reaches *** approach provides a new path for fast light focusing through wavefront shaping.

关键词： speckle optimization replace

Controller Placement in Software Defined Internet of Things Using Optimization Algorithm

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Computers, Materials & Continua 2022年第3期70卷 5073-5089页

作者： Sikander Hans Smarajit Ghosh Aman Kataria Vinod Karar Sarika Sharma Department of Electrical and Instrumentation Engineering Thapar Institute of Engineering&TechnologyPatialaIndia optical Devices and Systems CSIR-Central Scientific Instruments OrganizationSector 30-CChandigarh160030India Department of Electrical Engineering Government PolytechnicAmbala CityAmbala134003India

The current and future status of the internet is represented by the upcoming Internet of Things(IoT).The internet can connect the huge amount of data,which contains lot of processing operations and efforts to transfer the pieces of *** emerging IoT technology in which the smart ecosystem is enabled by the physical object fixed with software electronics,sensors and network ***,there are two trending technologies that take the platform i.e.,Software Defined Network(SDN)and IoT(SD-IoT).The main aim of the IoT network is to connect and organize different objects with the internet,which is managed with the control panel and data panel in the SD *** main issue and the challenging factors in this network are the increase in the delay and latency problem between the *** is more significant for wide area networks,because of the large packet propagation latency and the controller placement problem is more important in every *** the proposed work,IoT is implementing with adaptive fuzzy controller placement using the enhanced sunflower optimization(ESFO)algorithm and Pareto Optimal Controller placement tool(POCO)for the placement problem of the *** order to prove the efficiency of the proposed system,it is compared with other existing methods like PASIN,hybrid SD and PSO in terms of load balance,reduced number of controllers and average latency and *** 2 controllers,the proposed method obtains 400 miles as average latency,which is 22.2%smaller than PSO,76.9%lesser than hybrid SD and 91.89%lesser than PASIN.

关键词： SD-IoT adaptive fuzzy controller enhanced sunflower optimization(ESFO) POCO placement tool controller placement problem and minimum latency

Analysis and simulation of XPM intensity modulation

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Chinese Optics Letters 2005年第3期3卷 129-131页

作者：黄菁姚建铨 Applied Physics Department School of Precision instruments and Optoelectronics Engineering

Based on the split-step Fourier method and small signal analysis, an improved analytical solution which describes the cross-phase modulation (XPM) intensity is derived. It can suppress the spurious XPM intensity modulation efficiently in the whole transmission fiber. Thus it is more coincidence with the practical result. Furthermore, it is convenient, because it is independent of channel separation and the dispersion and nonlinear effects interact through the XPM intensity. A criterion of select the step size is described as the derived XPM intensity modulation being taken into account. It is non-uniform distribution and is the function of average signal power (or z). Compared with the conventional split-step method, the simulation accuracy is improved when the step size is determined by the improved XPM intensity.

关键词： Fourier optics High intensity light Interferometers optical beam splitters Signal processing

Nonlinear phase error analysis of equivalent thickness in a white-light spectral interferometer

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Nanotechnology and Precision Engineering 2019年第2期2卷 77-82页

作者： Tong Guo Qianwen Weng Bei Luo Jinping Chen Xing Fu Xiaotang Hu State Key Laboratory of Precision Measuring Technology and instruments Tianjin University

A white light spectral interferometry based on a Linnik type system was established to accurately measure the thin film thickness through transparent *** practical work,the equivalent thickness of a beam splitter and the mismatch of the objective lens introduce nonlinear phase *** a transparent medium also increases the equivalent *** simulation results showthat the equivalent thickness has a significant effect on thin film thickness ***,it is necessary to perform wavelength correction to provide a constant equivalent thickness for *** the experiments,some pieces of cover glasses as the transparent medium were added to the measured beam and then a standard thin film thickness of 1052.2±0.9 nm was tested through the transparent *** results demonstrate that our system has a nanometer-level accuracy for thin film thickness measurement through transparent medium with optical path compensation.

关键词： White light spectral interferometry Thin film thickness measurement Nonlinear phase Equivalent thickness Transparent medium

Rotation invariant pattern recognition with a volume holographic wavelet correlation processor

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Chinese Optics Letters 2003年第2期1卷 74-77页

作者：檀文钊薛庆增严瑛白金国藩 State Key Laboratory of Precision Measurement Technology and instruments Department of

A volume holographic wavelet correlation processor for performing rotation invariant pattern recognition is suggested. It uses wavelet transform to get the digital edge extraction of the original object and a single circular harmonic component is used as the matched filter to get good rotation invariance. The new filter used in this method is called wavelet circular harmonic component filter (WCHCF). Simulation results validate the theory and the experiment to recognize human faces with any rotation angle shows the utility of the newly proposed method.

关键词： optical correlation Wavelet transforms

Fiber core mode leakage induced by refractive index variation in high-power fiber laser

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Chinese Physics B 2017年第3期26卷 336-343页

作者：闫平王雪娇黄昱升付晨孙骏逸肖起榕李丹巩马理 Center for Photonics and Electronics Department of Precision Instruments Tsinghua University Beijing 100084 China

This paper presents an investigation of specific optical fiber core mode leakage behavior that occurs in high-power double-clad fiber lasers as a result of thermally-induced refractive index variations. A model of the power transfer between the core modes and the cladding modes during thermally-induced refractive index variations is established based on the mode coupling theory. The results of numerical simulations based on actual laser parameters are presented. Experimental measurements were also carried out, the results showed good agreement with the corresponding simulation results.

关键词： double-clad fiber laser and amplifier Core loss cladding mode mode coupling theory

Advances in Phase Detection Technique of Surface Plasmon Resonance Biosensor

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稀有金属材料与工程 2006年第A3期35卷 299-304页

作者： Yu Xinglong Wei Xing Deng Yan Liu Fangfang Dept. of Precision instruments Tsinghua University Beijing 100084 China

Surface plasmon resonance (SPR) sensing is an optical method based on evanescent *** biosensor can detect interaction of label-free biomolecules in *** further development,it can become a research instrument in *** biosensor can be divided intensity measurement and phase measurement,and the latter possesses higher sensitivity than the former *** paper attempts to summarize the SPR phase detection theory,discuss the major developments,compare the merits and deficiencies of various methods,and look forward to future prospects.

关键词： surface plasmon resonance(SPR) phase detection ellipsometry heterodyne interferometry

An optical glass plane angle measuring system with photoelectric autocollimator

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Nanotechnology and Precision Engineering 2019年第2期2卷 71-76页

作者： Yinguo Huang Yong Yang Jiaqi Liang Zhengqing Miao Meirong Zhao Yelong Zheng State Key Laboratory of Precision Measuring Technology and instruments Tianjin University

optical glass is the most widely used optical *** is necessary to measure its geometric characteristic quickly and reliably to meet the quality of optical glass.A vision measuring system combining photoelectric autocollimation system with high-precision rotary stage is designed to measure the parallelismand angle of optical glass plane.A novel method is proposed to overcome the difficulty ofmeasuring parallelismof optical *** model of parallelism and angle measurement is established and the feasibility is *** image processing algorithm combining Steger algorithm with the least square method is *** uncertainty of angle measurement system for angle measurement is 3.0″.The system can solve the problem of measuring the angle of optical glass with high precision and has important significance for optical system.

关键词： optical glass Plane angle Parallelism Photoelectric autocollimation system