高功率直接液冷固体薄片激光器的设计与实验

Design and Experiment on High-Power Direct-Liquid-Cooled Thin-Disk Solid-State Laser

设计了一种新型高功率直接液冷固体薄片激光器,由数十至数百片透射薄片密集堆叠构成分布式增益系统,使特种激光冷却液在增益介质间的平板微流道内流动以实现薄片直接冷却,有效解决了传统高功率固体激光器中增益介质焊接于热沉引入的热致应力、焊接面变形等问题。对该激光器的腔内损耗、腔内像差等参数进行了优化设计。分析了影响光-光转换效率的关键因素,根据像差特点给出了光束质量控制方法。将20片薄片以特别角度密集堆叠构成增益模块,利用两个增益模块在稳腔和非稳腔中均实现了功率大于9kW的准连续波(QCW)偏振激光输出,且这一实验室光源的体积小于0.4m3。

A novel high-power direct-liquid-cooled thin-disk solid-state laser is designed, in which the distributed gain system is composed of tens or hundreds transmission disks by intensive stacking. A special kind of laser cooling liquid flows in the planar micro-channels between gain media, and thus the direct cooling of disks is realized. The thermal stress, the reflective surface deformation and so on caused by the soldering between gain media and the heat-sink in the traditional high power solid-state laser are successfully avoided. In addition, the parameters such as intra-cavity loss and aberration are optimized. The key factors influencing the optical-to-optical conversion efficiency are analyzed, and the methods for controlling laser beam quality are introduced according to the thermal aberration characteristics. A gain module is composed of 20 disks by intensive stacking with a special angle. With these gain modules, a quasi-continuous-wave (QCW) polarized laser with an output power of larger than 9 kW is obtained in both stable and unstable cavities. Moreover, the whole volume of this laser source in laboratory is smaller than 0.4 m^3.