LD端面泵浦Nd:LiGd(MoO_4)_2晶体的主动调Q脉冲激光特性

Actively Q-switched pulse laser from LD end-pumped Nd∶LiGd(MoO_4)_2 crystals

加工了不同切向的Nd∶LiGd(MoO4)2晶体,测量并分析了它们的连续和主动调制激光特性。实验采用激光二极管(LD)端面泵浦的两镜直腔,其输出镜的耦合透过率为2%。在连续运转条件下,a切和c切晶体的最大输出功率分别为733,550mW,对应的光光转换效率分别为11.3%和6.7%。在声光调Q脉冲运转条件下,a切和c切晶体的最大平均输出功率分别为180,135mW,对应的光光转换效率分别为2.8%和1.7%。当重复频率为10kHz时,获得了最佳的脉冲实验结果,即:最大单脉冲能量和最高峰值功率来自a切晶体,分别为15.8J和85 W;最小的脉冲宽度来自c切晶体,为153ns。实验结果还显示,不同切向的Nd∶LiGd(MoO4)2晶体具有不同的输出波长,a切晶体为1 061nm,c切晶体为1 068nm,这种多波长发射特性有助于该类晶体在THz波领域的应用。

The Nd ： LiGd（MoO4）2 crystal samples with different orientations were machined, and their Continuous Wave （CW） and actively modulation laser characteristics were measured and ana- lyzed. A laser diode （LD） end-pumped double mirror cavity was used in the experiment, in which the coupling transmittance of the output mirror was 2 %. In CW operation conditions, the maximum out- put powers of a-cut and c-cut crystals were 733 mW and 550 mW, respectively, corresponding optical conversion efficiencies of 11.3% and 6.7%. In acousto-optic （A-O） operation conditions, the maxi- mum output powers of a-cut and c-cut crystals were 180 mW and 135mW, respectively, corresponding optical conversion efficiencies of 2.8% and 1. 7%. The optimum pulse experimental results are ob- tained when the pulse repetition frequency （PRF） is 10 kHz. It is shown that the largest pulse energy and the highest peak power are 15.8 J and 85 W, respectively, which come from the a-cut sample. The shortest pulse width is 153 ns, which comes from the c-cut sample. Experimental results indicate that Nd：LiGd（MoO4）2 nm for the a-cut sample the Nd ： LiGd（MoO4）2 crystals with different orientations can output different wavelengths in 1061 and in 1 068 nm for c-cut sample. The multi-wavelength emission property of crystal will help its applications to the THz-wave domain.