Passively Mode Locked Diode-End-Pumped Nd∶YAG Laser with In0.25 Ga0.75 As as Output Coupler

A novel InGaAs(LT-In0.25 Ga0.75 As) absorber grown by metal organic chemical vapor deposition at low temperature is presented.Using it as well as an output coupler,passive mode locking,which produces pulses as short as several hundred picoseconds for diode-end-pumped Nd∶YAG laser at 1.06μm,is realized.The pulse frequency is 150MHz.

Passive Q-Switching in a Flash-Lamp Pumped Nd∶YAG Laser with Ion-Implanted GaAs Wafer

A passive Q-switched flash-lamp-pumped Nd:YAG laser with the ion-implanted semi-insulating GaAs water is reported．The wafer is implanted with 400keV As~+ ions in the concentration of 10~(16)cm~(-2). Using GaAs wafer as an absorber and an output coupler．62ns pulse duration of single pulse is obtained.

LD Side-Pumped Passive Mode-Locked TEM00 Nd:YAG Laser Based on SESAM

We report an LD side-pumped continuous-wave passive mode-locked Nd:YAG laser with a Z-type folded cavity based on a semiconductor saturable absorber mirror (SESAM). The average output power 2.95 W of mode-locked laser with electro-optical conversion efficiency of 1.3% and high beam quality (M-x(2) = 1.25 and M-y(2) = 1.22) is achieved. The repetition rate of mode-locked pulse of 88 MHz with pulse energy of 34 nJ is obtained.

Surface amorphous and crystalline microstructure by alloying zirconium using Nd : YAG pulsed laser

A novel composite coating was synthesized by laser alloying of zirconium nanoparticles on an austenite stainless steel surface using a pulsed Nd:YAG laser. The coating contained duplex microstructures comprising an amorphous phase and an austenitic matrix. A discontinuous zirconium-containing region formed at a depth of 16 mum below the surface. The amorphous phase was present in the zirconium-rich region, with the composition of zirconium ranging from 7.8 to 14.5 at. pet. The formation of the amorphous phase was attributed to the zirconium addition. The hardness, corrosion, and wear-corrosion resistance of the irradiated coating were evidently enhanced compared to those of the stainless steel.

High electrical-to-green efficiency high stability intracavity-frequency-doubled Nd:YAG-LBO QCW 532 nm laser with a straight cavity

An electrical-to-green efficiency of more than 10% was demonstrated by intracavity-frequency-doubling a Q-switched diode-side-pumped Nd:YAG laser with a type II lithium triborate (LBO) crystal in a straight plano-concave cavity. An average power of 69.2 W at 532 nm was generated when electrical input power was 666 W. The corresponding electrical-to-green conversion efficiency is 10.4%. To the best of our knowledge, this is the highest electrical-to-green efficiency of second harmonic generation laser systems with side-pumped laser modules, ever reported. At about 66 W of green output power, the power fluctuation over 4 hours was better than +/-0.86%.

Dissimilar autogenous full penetration welding of superalloy K418 and 42CrMo steel by a high power CWNd : YAG laser

Experiments of autogenous laser full penetration welding between dissimilar cast Ni-based superalloy K418 and alloy steel 42CrMo flat plates with 3.5 mm thickness were conducted using a 3 kW continuous wave (CW) Nd:YAG laser. The influences of laser welding velocity, flow rate of side-blow shielding gas, defocusing distance were investigated. Microstructure of the welded seam was characterized by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). Mechanical properties of the welded seam were evaluated by microhardness and tensile strength testing. Results show that high quality full penetration laser-welded joint can be obtained by optimizing the welding velocity, flow rate of shielding gas and defocusing distance. The laser-welded seam have non-equilibrium solidified microstructures consisting of gamma-FeCr0.29Ni0.16C0.06 austenite solid solution dendrites as the dominant and very small amount of super-fine dispersed Ni3Al gamma' phase and Laves particles as well as MC needle-like carbides distributed in the interdendritic regions. Although the microhardness of the laser-welded seam was lower than that of the base metal, the strength of the joint was equal to that of the base metal and the fracture mechanism showed fine ductility. (c) 2007 Elsevier B.V. All rights reserved.

高重复率半导体激光抽运Nd：YAG放大器激光特性的实验研究

实验研究了高重复率、大功率半导体激光二极管阵列（LDA）侧面环绕抽运的Nd：YAG激光放大器的放大特性、热焦距变化和热致双折射效应引起的退偏特性。偏振光绎千赫兹高功率单通激光放大器，获得约3倍的光脉冲能量放大，脉冲宽度基本保持不变，其输出的P分量与S分量的能量比趋于常数3：1，实验测得的能量放大倍率及放大光束的椭圆偏振度与理论预期吻合很好。

大功率线阵激光二极管侧面抽运Nd：YAG激光器特性研究

对激光二极管（LD）抽运固体激光器中大功率线阵激光二极管三向对称侧面抽运的漫反射腔结构进行了研究。激光器使用Nd：YAG作为激光晶体，电光器件材料为KD^＊P晶体，漫反射体为陶瓷材料。实验表明，抽运光的利用率和均匀性有较大提高。在重复频率为10Hz下，实现了脉冲宽度8ns，最大平均功率为近2W的1064nm红外激光输出，激光器的效率有显著提高。

输出5W的电光调Q Nd：YAG陶瓷激光器

研究了激光二极管（LD）侧向抽运的Nd：YAG陶瓷电光调Q激光器的激光输出特性。该激光器采用九组激光二极管线阵列（LDA）侧面紧密环绕均匀排布的抽运结构，并用微通道热汇冷却技术冷却。在电光调Q方式下，重复频率为100Hz，抽运单脉冲能量为416mJ时，用尺寸为庐5mm×75mm，掺杂原子数分数为1％的Nd：YAG陶瓷棒，获得50mJ的1064nm激光输出，脉冲宽度为12ns，斜率效率达24％。并实验测量和分析了偏振片，KD^＊P晶体，四分之一波片等调Q器件的插入损耗。测量了输出激光时间波形和光斑的光强空间

激光二极管侧面抽运调Q倍频Nd:YAG激光器

对高平均功率输出的激光二极管侧面抽运电光调Q倍频 Nd:YAG激光器进行了研究，当采用90个60W的脉冲激光二极管阵列抽运时，在重复频率为10Hz下，实现了最大平均功率为1180mW的1064nm红外激光输出，光-光转换效率为11%。腔外倍频获得600mW的532nm绿光输出，倍频效率达到50%以上。

侧面抽运国产Nd∶YAG陶瓷棒的激光特性

实验研究了激光二极管阵列(LDA)侧向抽运国产Nd∶YAG陶瓷棒的准连续及被动调Q激光输出特性。该陶瓷激光器采用LDA侧面紧密环绕均匀排布的抽运结构,陶瓷棒抽运区域长度为20 mm,其总尺寸为3 mm×35 mm,掺杂原子数分数为~1%。在千赫兹准连续运转条件下,当平-平谐振腔的输出耦合镜透过率为47.3%时,获得最大平均功率23 W的1064 nm激光输出,光束发散角为4.5 mrad,斜率效率达12%。在谐振腔内插入Cr4+∶YAG晶体作为被动调Q开关,成功地实现了陶瓷激光器千赫兹重复频率调Q激光脉冲输出,当Cr4+∶YAG晶体初始透过率为60%时,输出激光脉冲宽度(半峰全宽)可窄至14.5 ns,调Q动静比约为40%。

Nd：YAG透明陶瓷的制备与激光输出

成功制备了高质量的Nd：YAG透明陶瓷，激光测试样品的尺寸为3mm×3mm×3mm,双面抛光、未镀膜，最高连续输出能量为1003mW，斜率效率为14％．

A comparison between TGT and Cz grown Nd : YAG

Large sized neodymium-doped Y3Al5O12 (Nd:YAG) laser crystals have been grown by temperature gradient technique (TGT) method and compared with Czochralski (Cz) method. The comparison of these two crystal growth methods has been listed. The results showed that the TGT method has many advantages over the Cz method. The concentration distribution of Nd ions in the crystals was determined and the absorption spectra of these crystals have been investigated and compared. The TGT grown highly doped Nd:YAG crystal has a larger absorption FWHM than that of Cz grown Nd:YAG crysral. Highly doped Nd:YAG (similar to 2.8 at. pct) crystals could be obtained by TGT.

Nd：YAG激光器光栅式扫描预处理的计算模拟与优化分析

采用计算模拟的方法．研究了光栅式扫描预处理的扫描方式以及脉冲能量波动、定位误差对预处理效率的影响。研究发现。脉冲能量波动及其定位误差使预处理效率降低，同时其影响与扫描方式之间存在相互调制作用．因此可以通过选择合适的扫描方式以及扫描间隔来优化预处理流程，提高预处理效率。此外发现，光斑呈等边三角形排列时的预处理效率优于正方形。