新型晶体BaTeMo2O9近-中红外拉曼激光性能研究

Near and mid-infrared lasers have attracted considerable attentions for numerous applications in civil and military fields，such as laser-guidance, infrared countermeasures, environmental monitoring and so on. The laser researches of our country in this spectrum are relatively backward. Therefore, the growth and laser output property studies of crystals with excellent nonlinear optical properties are important for practical applications and scientific significances. A novel crystal BaTeMo2O9(BTM) with large dimensions (34×37×45 mm3) has been grown in our lab. Our previous studies show that BTM poessess wide transmission band (0.4-5 μm), high optical damage tolerance, excellent crsytal growth habit, good thermal property,chemical and mechanical stabilities. In this project, the spontaneous Raman spectrum has been obtained and studied in detail. Then the Raman lasers under different wavelength lasers pumping are realized by using third-order nonlinear optcial effect-stimulated Raman scattering (SRS). In this project, our aim wavelengths include 1178 nm,1500nm,2.92μm,3.59μm,3.99μm and 589 nm which are produced by SRS or self-frequency-doubled effects at 1178 nm . After the Raman lasers have been realized preliminary, the corresponding parameters will be optimized, and more than one kind of high efficient Raman lasers operating in near or mid-infrared bands will be designed and fabricated. The possible practical applications of IR laser based on stumulated Raman scattering effect of BTM crystal will be studied.

近-中红外波段激光具有重要的民用和军用价值，目前国内此波段的激光研究相对落后。因此，生长性能优异的非线性光学晶体并对其激光性能进行研究具有重要的应用价值和科学意义。本课题在新型晶体BaTeMo2O9（BTM）自发拉曼光谱研究的基础上，以此晶体为研究客体，利用其宽的透光波段（0.4-5.5μm）、高的损伤阈值、良好的生长习性、适中的热学性能等优异的基本物理性能，通过三阶非线性光学效应-受激拉曼散射进行此晶体的近-中红外波段拉曼激光性能研究，完成对此晶体不同激光光源泵浦条件下的拉曼激光性能研究。本课题的主要目标波长为1178 nm，1500 nm，2.92 μm，3.59μm，3.99μm以及1178 nm拉曼自倍频后的589 nm；在优化泵浦方式、光路设计、镀膜等参数后，设计并制作一种或者几种具有高转换效率的目标波长激光器，并探索BTM晶体在近-中红外波段拉曼激光的实际应用。

受激拉曼散射是一种重要的激光波段拓展手段，拉曼晶体是高效拉曼激光输出的基础。本项目针对新型四元钼酸盐的代表性晶体BaTeMo2O9的受激拉曼散射特性进行了详细的研究。获得了1064nm泵浦条件下高效的的一阶、三阶和二阶、三阶双波长激光输出；其中单斜BaTeMo2O9晶体的拉曼增益系数是YVO4晶体晶体的1.1倍；其一阶拉曼激光输出光光转换效率达到48%；结合单斜BaTeMo2O9晶体优异的二阶非线性光学特性，实现了光光转换效率为11.7%的钠黄光拉曼自倍频输出；第一次设计和实现了双轴晶体（正交BaTeMo2O9）偏振棱镜，是目前唯一一种可以覆盖中红外波段的偏振器件，并且达到了实际应用的要求。本项目的实验结果对于此类其他材料在拉曼激光输出方面具有重要的借鉴意义，其光学器件有望实现实际应用，具有产业化前景。