Study of Helium-Neon Laser Amplification at 339 μ

The dependence of the gain of a helium–neon laser amplifier for 3.39-μ radiation as a function of input signal power, discharge current, mixture ratio, and total gas pressure has been investigated. A display of these results in the form of plots of the contours of constant amplification on the discharge currentpressure plane for various mixture ratios shows ridges of maximum gain running in the direction of increasing current and decreasing pressure. At high helium-to-neon ratios the ridge has two peaks. The saturation of the gain with input signal has been observed for a wide range of conditions and is in agreement with the theory of White et al.