报道了以Nd∶LiYF(Nd∶LYF)为增益介质、用硅酸镓镧(La3Ga5SiO14,LGS)晶体进行电光调Q的非稳腔调Q激光器的脉冲特性。Nd∶LiYF的两端按σ偏振1.053 μm光的布儒斯特角切割,不需另加起偏镜,实现了单一偏振光振荡。LGS晶体电光Q开关插入损耗小(2%),抗光伤阈值高(950 MW/cm2),与DKDP相比,具有不潮解等优点。当抽运能量为120 J、重复率3 Hz时,单脉冲输出能量为275 mJ,脉冲宽度为8 ns,动静比为76%,输出能量不稳定度小于3%,偏振度大于99%,光束发散角为0.7 mrad。文中还对本激光器偏振特性、非稳腔设计、LiYF导热性能和热透镜效应补偿进行了分析,对LGS电光调Q开关工作性能、工作方式以及存在的问题也进行了分析。

A Nd∶LiYF(Nd∶LYF) laser actively Q-switched with an electrooptic La3Ga5SiO14 (LGS) single crystal was designed. Each end of the Nd∶LiYF rod was cut at Brewster′s angle and the orientation of the two surfaces with respect to the crystal′s optic axis was such as to ensure operation at 1.053 μm, which saved the use of a polarizer. LGS Q-switch has the advantages of small insertion loss (2%), high damage threshold (950 MW/cm2) and non-deliquescence. When the pump energy was 120 J and the repetition rate was 3 Hz, the energy of single pulse was 275 mJ, pulse width was 8 ns, dynamic to static ratio was 76%, pulse fluctuation was smaller than 3%, polarization degree was more than 99%, and beam divergence was 0.7 mrad. The polarization characteristics of the laser, the design of the unstable cavity, the characteristics of the thermal effect of LiYF and its compensation were discussed. The principle, characteristics and problems of the LGS E-O Q-switch were also investigated.