中文摘要：

设计并研究了双晶四端泵浦的Tm：YLF激光器。利用Ansys软件中的稳态热分析模块计算了散热底板水通道在热交换系数分别为1000W／（m2·℃）、4000W／（m2·℃）、8000W／（m2·℃）和15000W／（m2·℃）以及采用TEC制冷时对应的晶体夹具及散热底板的温度分布。根据计算结果，在采用水温16℃中等强制对流及以上时与TEC制冷控温18～20℃时对Tm：YLF晶体冷却效果近似，可近似等效于TEC制冷。根据模拟计算的结果，设计了可用光纤耦合半导体激光器泵浦的U型腔结构Tm：YLF激光器。在采用16℃冷却水直接冷却晶体夹具时，单晶双端泵浦和双晶四端泵浦的Tm：YLF输出功率分别达到了25．9W和46W的激光输出，对应的斜效率分别为40．7％和37．1％。在实验过程中，晶体夹具未出现温度过高。实验结果说明设计的直接传导冷却系统可有效地冷却泵浦功率在140W时的双晶四端泵浦结构Tm：YLF晶体。

英文摘要：

The structure of double-crystal four-end pumped Tm：YLF laser was designed and studied. By using steady-state thermal analysis module in the Ansys software, the temperature distributions of the two crystal-clamps and cooling plate were calculated with the heat exchange coefficients of the cooling plate channels given as 1 000 W/（m2 ·℃ ）, 4 000 W/（m2 ·℃ ）, 8 000 W/（m2·℃ ） and 15 000 W/（m2 ·℃ ）. Meanwhile, the temperature distributions when the cooling-plate was assumed as a TEC cooler with temperatures of 18℃ and 20℃ were calculated, respectively. According to the calculated results, the cooling effect when the cooling-plate was given as medium convection intensity or higher would be equal to the result when taking the cooling-plate as TEC with temperature of 18℃ and 20℃. According to the simulation results, a U-shape Tm：YLF laser was designed pumped by fiber coupled laser diode. The output lasers with powers of 25.9 W and 46 W were achieved from single crystal and double crystals when the Tm：YLF crystal clamps and cooling plate were directly cooled by 16℃ cold water, corresponding to slope efficiencies of 40.7% and 37.1%, respectively. No over high temperature was observed in the whole experiment. The experiment results indicate that the designed direct conduction cooling system can effectively remove the heat load in single-crystal dual-end and double-crystal four-end pumped Tm： YLF laser.