Chodzko R A, Mason S B, Cross E F
Appl Opt. 1976 Sep 1;15(9):2137-44. doi: 10.1364/AO.15.002137.
A new type of resonator that generates an annular geometric mode by use of spherical mirrors has been developed. The four-element cavity consists of an external confocal unstable resonator with a double-sided 45 degrees coupling mirror and a flat feedback mirror. The flat feedback mirror is placed on the plane wave side of the confocal cavity to form an annular mode between the feedback mirror and the coupling mirror. A plane annular wave (matched to an annular gain medium) is fed back into the unstable resonator that alternately converges and diverges to produce a diverging annular output beam. Experiments were performed on a cw HF laser. Observations of mode patterns on the flat feedback mirror and the convex mirror and of far-field beam quality were made. Far-field measurements indicated near-diffraction-limited beam quality for a peak on-axis intensity mode on the convex mirror. A nearly uniform annular mode was observed on the flat feedback mirror.
一种利用球面镜产生环形几何模式的新型谐振器已被研制出来。四元件腔由一个带有双面45度耦合镜的外共焦非稳谐振器和一个平面反馈镜组成。平面反馈镜放置在共焦腔的平面波一侧，以在反馈镜和耦合镜之间形成环形模式。一个平面环形波（与环形增益介质匹配）被反馈到交替会聚和发散的非稳谐振器中，以产生发散的环形输出光束。在连续波HF激光器上进行了实验。对平面反馈镜和凸镜上的模式图案以及远场光束质量进行了观测。远场测量表明，凸镜上轴上强度峰值模式的光束质量接近衍射极限。在平面反馈镜上观察到了近乎均匀的环形模式。
