Granek H, Morency A J
Appl Opt. 1974 Feb 1;13(2):368-73. doi: 10.1364/AO.13.000368.
An experimental study was performed on the beam quality of large equivalent Fresnel number positive confocal unstable square resonators in a CO(2) electron-beam ionized laser. Near diffraction limited output was observed for a range of geometric output coupling from 34% to 85%, with a sensitivity to the particular value of equivalent Fresnel number being found only for the lowest output coupling.
对二氧化碳电子束电离激光器中具有大等效菲涅尔数的正共焦非稳方腔的光束质量进行了实验研究。在34%至85%的一系列几何输出耦合范围内观察到接近衍射极限的输出，并且仅在最低输出耦合时发现对等效菲涅尔数的特定值敏感。
