Determination of unsaturated gain of an He–Ne laser with transverse microwave pumping

An experimental study was made of the unsaturated gain of the active medium of an He–Ne laser pumped transversely by a microwave discharge. The gain increased monotonically when the pump frequency was increased and in the range 880–900 MHz it was 50–60% higher than the gain for a dc discharge. Moreover, an increase in the pump frequency reduced the optimal specific pump power.