Experimental investigation of the competition between opposite waves in a rapidly pumped ring gas laser

A study was made of the influence of the saturation of the active medium on the competition between the opposite waves in a ring resonator. Hie experiments were carried out on an He–Ne laser emitting at λ = 3.39 μ. The dependences of the width of the competition zone (the zone of stable one-wave emission) on the excess over the excitation threshold were determined for different pressures in the gas mixture. When the pressure was 0.9–1 Torr, the competition zone disappeared for moderate values of the excess and reappeared at higher pumping rates. At high pressures, these dependences had a minimum which shifted toward lower pumping rates when the pressure was increased. The results obtained were in qualitative agreement with a theory developed earlie