高功率循环流动型半导体泵浦碱金属蒸汽激光器研究进展（特邀）

半导体泵浦碱金属蒸汽激光器（DPAL）兼具半导体激光器和气体激光器的技术特点，具有量子效率高、受激发射截面大、折射率扰动较小和热管理便捷等优势，可实现高效率、高功率和高光束质量近红外激光输出，在工业制造、军事、医疗和科研等领域具有重要的应用价值。对于封闭静止型DPAL，在高功率泵浦情况下，蒸汽池内工作气体温度升高，热效应严重，造成DPAL性能下降。而循环流动型DPAL利用气体流动带走废热，可显著缓解工作气体的热效应，从而实现高功率激光输出。目前，循环流动型DPAL已成为实现高功率激光输出的主要技术路线，引发了越来越多的关注和研究。文中将介绍循环流动型DPAL的基本原理，概述其国内外发展现状，分析其高功率运转情况下的主要问题和解决途径，并对循环流动型DPAL的发展趋势进行展望。

Research progress on the high power flowing-gas circulation diode-pumped alkali vapor laser (Invited)

Diode pumped alkali metal vapor laser (DPAL) combines the technical characteristics of both diode laser and gas laser, with the advantages of high quantum efficiency, large excited emission cross section, small refractive index perturbation, convenient thermal management and rich output wavelength, which can achieve high efficiency, high power and high beam quality near infrared laser output, and has important applications in industrial manufacturing, military, medical and scientific research fields. For closed static DPAL, under the condition of high power pump, the working gas temperature in the steam pool increases, and the thermal effect is serious, resulting in the decline of DPAL performance. The circulating flow DPAL uses gas flow to take away waste heat, which can significantly alleviate the thermal effect of working gas, so as to achieve high-power laser output. At present, it has become the mainstream technical route to achieve high power laser output. In this paper, the principles and current development of the flowing-gas circulation DPAL are outlined, the obstacles and solutions of high power scaling of DPAL are analysed, and prospects for the future development of high-power alkali metal lasers.