利用双光学参量振荡器结构输出4.3μm激光方案

Theoretical investigation on a method generating 4.3 μm laser based on the tandem optical parametric oscillator

鉴于中红外激光的重要应用价值,提出了分别用2.1μm和2.7μm激光泵浦ZnGeP2(ZGP)光学参数振荡器(OPO),采用不同相位匹配方式输出4.3μm的激光方案,计算并比较了匹配角、走离角、有效非线性系数、泵浦光的允许线宽、允许发散角、参量输出光的线宽以及ZGP对泵浦光的吸收系数等,确定最佳方案为利用1.06μm激光泵浦内腔式KTP OPO输出的2.7μm激光作为泵浦源,采用第Ⅱ类匹配方式泵浦ZGP OPO输出4.3μm激光,该方案克服了传统方案的不足,并给出了实验装置图,选择了合适的实验参数,计算了相应参数对ZGP OPO阈值的影响。2.7μm初步实验结果表明:此方案切实可行,为下一步4.3μm激光输出实验奠定了基础。

The scheme of ZnGeP2 （ZGP） optical parametric oscillator （OPO） generating 4.3μm laser with different phase matching types pumped by 2.1 μm and 2.7 μm laser respectively were presented in view of the important application value of mid-infrared laser. The phase matching angle, walkoff angle, effective nonlinear coefficient, allowable linewidth and divergence angle of pump laser, linewidth of output laser and absorption coefficient of ZGP to pump laser were calculated and compared. The results show that the optimal scheme to generate 4.3 OLin laser based on ZGP OPO is to use 2.7 μm laser as pump source, which was generated by 1.06 μm laser pumped KTP intracavity OPO with type 11 phase matching. The experimental scheme and proper parameters were presented. The effects of parameters on the threshold of ZGP OPO were analyzed. The results of theoretical calculation and preliminary experiment of 2.7μm laser show that it is feasible to generate 4.3μm laser by this method, which lays a foundation for the further experiments.