基于循环级联的Er:YAG晶体波导激光器2.94μm高效率输出机理研究

构建基于循环级联的Er:YAG晶体波导双谐振激光器新结构，开展常温低掺杂Er:YAG激光器2.94μm中红外激光高效率输出机理研究，为高平均功率、高光束质量的中红外激光输出提供新方法。首先设计、制备晶体方波导增益介质和泵浦结构，构建新结构激光器，常温级联输出中红外激光，研究级联输出光谱特性。其次，通过外部输入1.6-1.9μm的可调谐激光，研究Er:YAG晶体的激发态吸收光谱特性。再次，采用在腔内插入波长选择元件的方法，选择、稳定近红外级联光；通过级联光与基质的声子辅助能量转换方法，产生上转换光，研究声子辅助作用影响上转换光效率的机理，获得高效的非共振激发态吸收循环级联。最后，优化双谐振腔光学元件的参数，进一步提高2.94μm中红外激光稳定输出效率，获得高平均功率、高光束质量2.94μm中红外激光输出。为探索固体激光器中红外激光高效率输出提供一新途径，为医学、前沿科学的研究提供支撑。

A novel structure of Er:YAG crystal waveguide double resonance laser based on cyclic cascade is constructed. The mechanism of high efficiency output of 2.94 μ m mid infrared laser with low dopant concentration Er:YAG at room temperature is studied, which provides a new method for high average power and high beam quality mid infrared laser output. Firstly, we design and fabricate the gain medium and pump structure of crystal square waveguide, build a new structure laser, cascade output mid infrared laser at room temperature, and study the spectral characteristics of cascade output. Secondly, the excited state absorption spectrum of Er:YAG crystal is studied by external input of 1.6-1.9μm tunable laser. Thirdly, we select and stabilize near-infrared cascade light by inserting a wavelength selective element in the cavity. By using the method of phonon assisted energy conversion between cascaded light and substrate to generate up conversion light, the mechanism of phonon assisted effect on up conversion optical efficiency is studied, to acquire efficient non-resonant excited-state absorption. Finally, by optimizing the parameters of the optical elements in dual resonator, the stable output efficiency of 2.94 μ m mid infrared laser is further improved, and the high average power and high beam quality of 2.94 μ m mid infrared laser output is obtained. This project will provide a new way to explore the high efficiency output of mid infrared lasers, simultaneously offers great support to research in medicine, frontier science.