In order to get high efficiency and high brightness laser output with single fiber coupled laser diode array, two laser diode array bars which have 40-W continuous wave (CW) output power at 980-nm wavelength are used in the experiment. The laser diode bars are collimated by two pieces of cylindrical micro lenses in the fast axis direction, and in the slow axis direction step mirrors are used to divide the beams of light to shape the output beam symmetrically. A piece of polarizing beam splitter cube is used to combine the two shaped beams. The focused output beam is coupled into a multimode fiber. More than 55-W output power is obtained from the fiber with core diameter of 400 microns and numerical aperture of 0.22, the total coupling efficiency is about 70% and the brightness is up to 10^(9) level.

In order to get stable continuous wave (CW) mode-locked (ML) laser, conventionally, the laser cavity was designed to reach very small mode radius in the laser crystal to make the laser material saturated. While for the laser diode (LD) end pumped Nd:YVO4 without fiber coupling transmission, as long as choosing the appropriate short focus lens and making the focus area in front of the Nd:YVO4 small enough, we found even large cavity mode volume can make the laser material saturated. In addition, relatively large cavity mode volume can make high power output with single mode come true. Ideal beam quality without high order transverse mode oscillating, the CW ML state turned to be very stable. Accordingly, relatively large mode volume in the laser crystal was designed with semiconductor saturated absorber mirror (SESAM), over 1.5-W CW ML output with near diffraction limited was acquired. The optical-to-optical conversion efficiency reached 30%.

报道了采用大功率国产光纤束模块端面抽运Nd:YVO4激光晶体的腔外三倍频紫外激光器, 用声光调Q技术实现了高功率高光束质量基频光输出。采用LBO Ⅰ类相位匹配和LBO Ⅱ类相位匹配的腔外倍频方法, 并利用凹面反射镜的方式进行聚焦, 避免了1064 nm和532 nm激光聚焦时由于波长的不同而产生的色差效应, 有效地提高了三倍频的倍频效率。最终在注入抽运光功率为23.3 W, 声光调Q激光器的调制频率为20 kHz的工作条件下, 基频光输出功率为7.28 W时, 得到紫外激光输出功率为1.86 W, 1064 nm基频光到355 nm紫外激光的光-光转换效率为25.5%, 此外, 对紫外激光光束质量的测试表明, 该紫外激光器具有高功率输出的同时仍有很好的光束质量。

基于激光切片原理的分析,给出了厚硅片的高速激光切片方法,采用平凸腔补偿工作物质的热透镜效应,利用Nd:YAG棒本身的自孔径选模作用,获得了光束质量因子M²等于4.19的50 W 1.064μm激光输出。选取合适的扩束倍数、重复频率和出气孔直径,当切割0.75 mm厚的硅片时,切片速度达400 mm/min;当切割两层叠放的0.75 mm厚的硅片时,切片速度达到100 mm/min。切片的切口光滑,切缝较窄,重复精度高,切片质量好,达到用传统方法难以达到的切片效果。

对三种具有商业价值的非线性光学晶体——LBO,KTP,BBO热透镜效应进行了分析研究,通过具体理论计算,给出了三种非线性光学晶体的热透镜焦距在保持输出功率没有变化的情况下随入射到晶体表面的光斑大小的变化曲线,并且理论计算出在平均功率为20 W的绿光激光器中KTP晶体在入射基频光斑w=368 μm的热焦距为852 mm,实验中测得的M2值与理论计算吻合较好。

用端面研磨法来弥补激光棒热透镜效应是一种传统的方法。在推导更为精确的激光棒端面研磨半径公式时,发现了激光棒的自消热透镜效应现象。把激光棒等效为梯度折射率棒,得到了新的热透镜焦距公式。从新的焦距公式出发,理论证明了激光棒自消热透镜效应现象,并详细分析了该效应产生的原因。

对二极管横向抽运1.319μm大功率Nd:YAG激光器进行实验研究.采用横向抽运方式(CEO公司RD module),以φ4×115(单位mm)Nd:YAG晶体为激光工作物质,通过谐振腔设计和小孔光阑相结合的手段抑制高阶模的振荡,选取单横模,并且达到补偿晶体的较大热效应、提高单模的模式竞争能力的目的.在抽运光功率为343 W的条件下,得到功率大于6 W的TEM00模1.319μm连续激光输出,光束质量因子M2<2,激光功率不稳定度低于2%,最大光-光转换效率约为1.74%.

将渐变反射率镜(VRM)虚共焦非稳腔成功地应用于光参量振荡器(OPO)，在工作重复频率20 Hz时，获得了能量40 mJ，光束发散角4 mrad的1.57 μm激光输出。

实验研究了非临界相位匹配(NCPM)的内腔式KTP光学参量振荡器(OPO)的光束发散角与OPO谐振腔参数的关系.证明了望远镜型共焦非稳谐振腔是压缩OPO光束发散角的有效方法.

将变反射率镜(VRM）非稳腔成功地应用于可调谐Ti:Al2O3激光器，有效地提高了Ti:Al2O3激光的光束质量，并利用LBO晶体作为倍频器获得了396nm～440nm的蓝色可调谐激光输出，最大输出能量为26mJ，最高倍频效率为27.2%。