多热焦距激光谐振腔与单热焦距谐振腔相比, 具有结构灵活、热管理简便等优点, 然而其热稳定性受到激光头分布等因素影响, 需要优化设计以实现多热焦距激光谐振腔高功率稳定输出。理论分析了激光头分布对多热焦距激光谐振腔热稳定性的影响, 对比了单热焦距双棒谐振腔、双热焦距3棒对称谐振腔和双热焦距3棒非对称谐振腔的热稳定性。根据理论分析, 采用不同热焦距的激光头构成双热焦距3棒串接对称热近非稳腔, 通过优化设计, 当抽运功率为3480 W时, 该连续波1064 nm Nd∶YAG激光系统获得稳定输出, 最高输出功率达1125 W, 光-光转换效率达32%, 光束质量约15 mm·mrad。

The structure and thermal management of many-heat focus resonator is more flexible than that of single heat focus resonator. Whereas, the stability of many- thermal focus resonator is affected by more factors, such as the arranging of laser head, which need optimizing design. To get stability output, the single focus double rod resonator, the double focus 3 rod symmetrical resonator and the double focus 3 rod laser with unsymmetrical cavity are analyzed and compared. With the theoretic results, by mounting three laser heads with two thermal focus into a flat-flat symmetrical thermally-near-unstable resonator, a continuous-wave power stabilized output of 1125 W at 1064 nm is obtained with a optical-optical conversion efficiency of 32% and a beam quality of 15 mm·mrad under the pumping power of 3480 W.