热变形谐振腔的激光模式理论分析

Theoretical analyses of laser modes for thermal deformation resonators

应用微扰理论 ,对微热变形腔的激光模式进行了理论计算与分析 ;给出了激光模式之间的耦合以及等效光束发散角与镜面变形量之间的关系。结果表明 :镜面中心处热变形量越大 ,模式之间的耦合越强 ,激光腔模式发生畸变就越严重 ;当镜面中心处热变形量为 0 .5λ时 ,基模 TEM0 的中心光强将下降 50 % ,其等效光束发散角将增大到镜面无变形时的 2倍。

Laser modes in thermal deformation resonators are calculated and analyzed by means of perturbation methods. The coupling among laser modes and the relations between equivalent beam spread angle and the surface deformation of the mirrors are obtained. The theoretical results show that the bigger the thermal deformation at the center of a mirror and the stronger the coupling among laser modes, the more seriously the modes in a laser resonator are distorted. When the thermal deformation value at the center of a mirror is 0.5λ, the central laser intensity of TEM 0 is reduced to 50% , and the equivalent beam spread angle is increased to 2 times of the ideal mirror.