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Thermal Performance of Laser Diode Array under Constant Convective Heat Transfer Boundary Condition

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Chinese Physics Letters 2007年第7期24卷 1934-1937页

作者：殷聪黄磊何发红巩马理 center for photonics and electronics State Key Laboratory of Tribology Department of Precision Instruments and Mechanology Tsinghua University Beijing 100084

Three-dimensional heat transfer model of laser diode array under constant convective heat transfer coefficient boundary condition is established and analytical temperature profiles within its heat sink are obtained by separation of variables. The influences on thermal resistance and maximum temperature variation among emitters from heat sink structure parameters and convective heat transfer coefficient are brought forward. The derived formula enables the thermal optimization of laser diode array.

关键词： SINK

Theoretical analysis of the mode coupling induced by heat of large-pitch micro-structured fibers

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Chinese Physics B 2015年第2期24卷 176-180页

作者：张海涛陈丹郝杰闫平巩马理 center for photonics and electronics State Key Laboratory of TribologyDepartment of Precision InstrumentsTsinghua University Southwest Institute of Technical Physics

In this paper,a theoretical model to analyze the mode coupling induced by heat,when the fiber amplifier works at high power configuration,is *** model mainly takes into consideration the mode field change due to the thermally induced refractive index change and the coupling between modes.A method to predict the largest average output power of fiber is also proposed according to the mode coupling *** largest average output power of a large pitch fiber with a core diameter of 190 μm and an available pulse energy of 100 mJ is predicted to be 540 W,which is the highest in large mode field fibers.

关键词： fiber amplifier large pitch fiber mode coupling

Compact,efficient diode-end-pumped Nd:GdVO_4 slab continuous-wave 912-nm laser

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Chinese Physics B 2012年第2期21卷 333-337页

作者： Liu Huan Gong Ma-Li State Key Laboratory of Tribology Center for Photonics and ElectronicsDepartment of Precision Instruments and MechanologyTsinghua UniversityBeijing 100084China

A fiber-coupled laser-diode （LD） end-pumped Nd：GdVO4 slab continuous-wave （CW） 912-nm laser and an LD bar end-pumped Nd：GdVO4 slab CW 912-nm laser are both demonstrated in this paper. Using the fiber-coupled LD of end-pumped type, a highest CW 912-nm laser output power of 10.17 W is obtained with a high optical to-optical conversion efficiency of 24.6% and a slope efficiency of 34.5%. The measured M2 factors of beam quality in x and y directions are 5.3 and 5.1, respectively. Besides, an LD bar of end-pumped type is used to realize CW 912-nm laser output, which has the advantages of compactness and low cost. When the pump power is 38.8 W, the output power is 8.87 W and the measured M^2 factors of beam quality in x and y directions are 16 and 1.31, respectively. In order to improve the beam quality of the 912-nm laser at x direction, a new quasi-concentric laser resonator will be designed, and an LD bar end-pumped Nd：GdVO4 slab high-power CW 912-nm TEM00 laser will be realized in the future.

关键词： diode-end-pumped Nd:GdVO4 slab LD bar 912-nm laser

Manipulation on human red blood cells with femtosecond optical tweezers

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Chinese Optics Letters 2008年第12期6卷 919-921页

作者：周明杨海峰狄建科赵恩兰 photonics Fabrication Science center Jiangsu University

Different types of femtosecond optical tweezers have become a powerful tool in the modern biological field. However, how to control the irregular targets, including biological cells, using femtosecond optical tweezers remains to be explored. In this study, human red blood cells （hRBCs） are manipulated with femtosecond optical tweezers, and their states under different laser powers are investigated. The results indicate that optical potential traps only can capture the edge of hRBCs under the laser power from 1.4 to 2.8 mW, while it can make hRBCs turn over with the laser power more than 2.8 mW. It is suggested that femtosecond optical tweezers could not only manipulate biological cells, but also subtly control its states by adjusting the laser power.

关键词： Blood Hemoglobin oxygen saturation Laser optics Lasers Optical instruments Pulsed laser deposition

Analysis of Laser Diode Pumped Solid-State Laser Resonator by the Transform Circle Approach

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Chinese Physics Letters 2000年第3期17卷 203-205页

作者： SONG Feng ZHANG Guang-Yin XU Jing-Jun ZHANG Chao-Bo photonics center Nankai UniversityTianjin 300071

The typical laser characteristics of a laser diode pumped,solid-state laser with a Z-type resonator structure are analyzed by the transform circle *** waists change with the thennal focus length of the lasing medium so that the output power becomes *** particular,there is a very unstable operation region when the pump power is of medium magnitude.A method is put forward to avoid this situation.

关键词： pumped pump resonator

Pulsed pumped Yb-doped fiber amplifier at low repetition rate

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Chinese Optics Letters 2005年第5期3卷 249-250页

作者：叶昌庚闫平巩马理雷鸣 center for photonics and electronics State Key Laboratory of Tribology Department of Precision Instruments Tsinghua University Beijing 100084

A pulsed pumped Yb-doped double-clad fiber (DCF) master-oscillator power amplifier (MOPA) at low repetition rate is reported. Seeded by a passive Q-switched Nd:YAG microchip laser, the fiber amplifier can generate 167-kW peak-power and 0.83-ns duration pulses at 200-Hz repetition rate. Because of the pulsed pump approach, the amplified spontaneous emission (ASE) and the spurious lasing between pulses are well avoided, and the repetition rate can be set freely from single-shot to 1 kHz. Peak power scaling limitations that arise from the fiber facet damage are discussed.

关键词： Optically pumped lasers Pulsed laser applications Q switched lasers Spontaneous emission Ytterbium

Investigation of ultrafast electron dynamics of nickel film and micro-nano-structure film

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Chinese Optics Letters 2009年第7期7卷 650-652页

作者：金卫凤周明刘长隆王辉刘会霞任乃飞 photonics Fabrication Science center Jiangsu University

The electron thermalization and relaxation processes in ferromagnetic nickel thin film and micro-nano- structure film have been studied by measuring the transient change after excitation by a femtosecond laser pulse. The measurements indicate that the electron thermalization time is between 18 and 47 fs. This is somewhat faster than the value reported before. And the thermalization time of the micro-nano-structure film is much longer than the nickel film. We deduce that it is caused by the discontinuity of the electron band close to the Fermi level in the micro-nano-structure nickel film.

关键词： Electrons Laser excitation Metallic films Nanostructures Nickel Nickel alloys Pulsed laser applications

Generation of arbitrary vector vortex beams on hybrid-order Poincaré sphere

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photonics Research 2017年第1期5卷 15-21页

作者： Zhenxing Liu Yuanyuan Liu Yougang Ke Yachao Liu Weixing Shu Hailu Luo Shuangchun Wen Laboratory for Spin photonics School of Physics and Electronics Hunan University

We propose theoretically and verify experimentally a method of combining a q-plate and a spiral phase plate to generate arbitrary vector vortex beams on a hybrid-order Poincaré sphere. We demonstrate that a vector vortex beam can be decomposed into a vector beam and a vortex, whereby the generation can be realized by sequentially using a q-plate and a spiral phase plate. The generated vector beam, vortex, and vector vortex beam are verified and show good agreement with the prediction. Another advantage that should be pointed out is that the spiral phase plate and q-plate are both fabricated on silica substrates, suggesting the potential possibility to integrate the two structures on a single plate. Based on a compact method of transmissive-type transformation, our scheme may have potential applications in future integrated optical devices.

关键词： Generation of arbitrary vector vortex beams on hybrid-order Poincar sphere

Spectroscopic properties of heavily Ho^(3+) -doped barium yttrium fluoride crystals

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Chinese Physics B 2015年第9期24卷 299-306页

作者：吉恩才柳强聂明明罗辉胡玉熙官周国巩马理 State Key Laboratory of Precision Measurement Technology and Instruments Center for Photonics and ElectronicsDepartment of Precision InstrumentTsinghua University Southwest Technical Institute of Physics

The 30 at.% Ho： BaY2F8 crystals were grown by the Czochralski method, and their spectroscopic properties are analyzed systematically by standard Judd–Ofelt theory. The Judd–Ofelt intensity parameters are estimated to be Ω2 =6.74 × 10^-20cm^2,Ω4 = 1.20 × 10^-20cm^2, and Ω6= 0.66 × 10^-20cm^2, and the fluorescence branching ratios and radiative lifetimes for a series of excited state manifolds are also determined. The emission cross sections with our measured infrared luminescence spectra, especially important for 4.1 μm, are calculated to be about 4.37 × 10^-21cm^2. The crystal quality is preliminarily tested through a mid-infrared laser emission experiment.

关键词： Ho:BYF crystal Judd–Ofelt theory mid-infrared laser