介绍了基于电光调Q与MOPA技术的高重频、窄脉宽的1 064 nm和532 nm双波长固体激光器。采用Nd:YVO4晶体作为激光增益介质，加以电光调Q，得到1 064 nm本振激光输出，为获得稳定脉冲激光输出，在激光器本振级的基础之上，再将其进行两级行波放大，当两级放大级泵浦电流均为6.7 A，重复频率为10 kHz时，实现了输出功率为31.4 W，脉宽为6.2 ns的基频光输出，功率稳定性RMS为0.25%，采用腔外倍频获得16.6 W的532 nm激光输出，1 064 nm基频光到532 nm倍频光的转换效率可达53%。

利用MOPA激光种子源, 结合氙灯泵浦行波放大方法研制了高能量脉宽可调1 064 nm波段激光器。激光器采用电调制脉宽方式控制MOPA光纤激光器脉冲信号的输出, 在保证高光束质量的前提下, 实现了脉宽8.6~220.9 ns可调的1 064 nm种子激光输出。选用双通放大级设计, 利用氙灯泵浦Nd:YAG晶体实现五级行波放大, 分析讨论了抑制自激振荡方法和行波放大过程中脉宽变窄的原因。当氙灯注入能量为60 J, 重复频率10 Hz时, 实现了脉宽调范围为4.2~173.3 ns的稳定1 064 nm激光输出, 单脉冲能量最高可达158 mJ。

采用非稳腔光参量振荡(OPO)研制了千赫兹重复频率人眼安全波段全固态激光器。激光器采用电光调Q方式、脉冲激光二极管(LD)侧面泵浦Nd:YAG激光晶体实现了高光束质量的1.064 μm基频激光。光参量振荡部分采用Ⅱ类非临界相位匹配KTP晶体, 为了获得较好的光束质量, OPO谐振腔采用平凸非稳定谐振腔结构, 实现了千赫兹重频、窄脉冲1.57 μm波段激光输出。在脉冲激光二极管泵浦电流为125 A、电光调Q重复频率为1 kHz时, 1.57 μm激光输出最大平均功率达到了4.67 W, 激光脉冲宽度为4.3 ns, 功率不稳定度为3%, 激光泵浦阈值约为45 A。

报道了一台高效率、高峰值功率351 nm紫外激光器。采用激光二极管(LD)端面抽运Nd:YLF晶体声光调Q获得准连续窄脉宽1 053 nm基波振荡, 腔外两块LiB3O5(LBO)晶体紧贴输出镜放置, 对基频光进行二倍频和三倍频, 获得了高峰值功率351 nm紫外激光输出。在LD抽运功率为14 W、声光调 Q 激光器的调制频率为1 kHz的工作条件下, 基波平均输出功率为1.45 W时, 得到351 nm紫外激光平均输出功率450 mW, 1 053 nm基频光到351 nm紫外光转换效率高达31.04%, 脉冲宽度为7.5 ns, 峰值功率达60 kW, 光束质量良好。

报道了LD侧面抽运Nd∶YVO4 532 nm准连续绿光激光器。为了获得高功率的532 nm绿光输出，通过采用声光调Q技术和LD侧面抽运Nd∶YVO4技术来获得高功率线偏振的1064 nm激光输出。采用Ⅰ类相位匹配三硼酸锂(LBO)晶体腔内倍频，实现高功率532 nm激光输出。在电源输出电流为30 A、声光调Q的调制频率为20 kHz的工作条件下，获得平均输出功率为33 W的线偏振1064 nm基频光，通过LBO晶体倍频获得平均输出功率为23.5 W的532 nm绿光。1064 nm基频光到532 nm绿光的光-光转换效率达71.2%，脉冲宽度为44.3 ns，偏振比为254∶1。

An optical fiber bundle array coupling module with high output power is proposed. The device integrates the coupling technique of the high power laser diode array (LDA) and the flat end-surfaces of fiber array. This module can efficiently couple the output laser of the LDA into the 19-fiber array through the flat-end surface. The fibers are ordinally fixed precisely on the V-grooves, and the fiber array has the same arrange period with the semiconductor laser units of LDA. A cylindrical fiber lens is fixed at the front of the LDA, which will greatly reduce the divergence of the laser beam and assure the laser beam to totally pass through into the end surface of fibers. High output power of 33.2 W of the fiber optic coupling of LDA is achieved, and maximal coupling efficiency is 84%.

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%.