Investigation of a two-pass CO2 amplifier for operation with a wavefront-reversing mirror

It was demonstrated experimentally that for a pulse duration of ~ 1 μsec the amplifying properties of the active medium in photoionization CO₂ lasers can be estimated using the steady-state approximation formulas. The gain and the saturation parameter, averaged over the pulse duration, were measured for a number of P branch CO₂ lines including the 10P(8) and 10P(10) lines for which the maximum reflection coefficient was achieved using a wavefront-reversing mirror and a four-wave interaction in SF₆. A study was made of a two-pass CO₂ amplifier intended for operation with a wavefront-reversing mirror and providing a gain of ~10⁴ with an output energy of 60 J.