稳定光学谐振腔高斯光束的发散角理论

当考虑到高斯光束在通过界面时参数的变化后,光学谐振腔输出高斯光束的远场发散角(外发散角)一般不等于自由空间中高斯光束的远场发散角(定义为内发散角),使用ABCD矩阵,g-和g-参数表示,导出了在基模和多模工作时内、外发散角的一般公式并对(1)固体激光腔;(2)输出镜为平面镜;(3)激光棒端面直接镀膜成镜;(4)热透镜腔等四个典型例证作了比较和讨论。

Theory of Gaussian beam divergence for stable optical resonators

The Gaussian beam divergence for optical resonators (external divergence angle) is not equal to that in free space (internal divergence angle, as a definition) when the change of beam parameter through a dielectric interface has been considered. In this paper, using ABCD-matrix, g-and g*-parameterg, the formulae for external and internal divergence angles in fundamental mode operation and multimode operation have been derived analytically. Four typical examples have been compared and discussed: (l)optical resonators of solid-state lasers; (2) resonators with one plane mirror; (3) directly coated laser rods; (4) resonators with a thermal lens.