本系统由Nd:YAG二、三倍频激光泵浦有机染料,在可见区获得调谐激光输出,继而再利用喇曼移频技术扩展波段,如图所示。为了使Nd:YAG的输出同时具有高的功率密度和良好的光束质量,以便有效的产生各次谐波,采用衍射限输出的虚共焦非稳腔作为本振级,只需加一级放大,即达到基频800mj,二倍频350mj(最大450mj),三倍频150mj(最大190mj)的输出。整个系统简单,尺寸缩小,稳定性、可靠性增加。对于高重复率工作的非稳腔激光器,首先要合理选取腔长、输出耦合度、激光晶体棒直径、腔镜曲率半径等参数,还必须考虑工作物质的热效应,这对保证高质量的输出光束和稳定性是极为重要的。二倍晶体采用KD＊P(Ⅱ型)和β-BaB_2O_4(Ⅰ型)。KD＊P的抗激光损伤阈值高,光学质量好;β-BaB_2O_4是一种新型的非线性晶体,其非线性系数高,不潮解,在相位匹配 The system by Nd: YAG second and third harmonic laser pumped organic dye, tunable laser output in the visible region, and then use Raman shift band to expand the band, as shown. In order to make Nd: YAG output have both high power density and good beam quality, in order to effectively produce each harmonic, using the diffraction limit output of the virtual confocal unstable resonator as the local oscillator level, just add a zoom , That is, the output of the base frequency 800mj, double frequency 350mj (maximum 450mj), triple frequency 150mj (maximum 190mj). The entire system is simple, reduced size, stability, increased reliability. For non-steady-state lasers operating at high repetition rate, the parameters such as cavity length, output coupling degree, diameter of laser crystal rod, and radius of curvature of the cavity must be properly selected. The thermal effect of the working substance must also be taken into consideration. And stability is extremely important. The double crystal adopts KD * P (type Ⅱ) and β-BaB 2 O 4 (type I). KD * P has high anti-laser damage threshold and good optical quality. Β-BaB 2 O 4 is a new type of nonlinear crystal with high non-linear coefficient and no deliquescence. In phase matching