A continuously operating 7.18-µ laser oscillator has been built using optically pumped cesium vapor as the amplifying medium. A power of 50 µw is coupled out of the confocal resonator by means of a 45° BaF2 pickoff window. The measured intensity distribution is in good agreement with that derived from the Boyd-Gordon expression for the lowest-order mode.
P. Rabinowitz, S. Jacobs, and G. Gould, "Continuous Optically Pumped Cs Laser," Appl. Opt. 1, 513-516 (1962)