Ft. Arecchi et al., PATTERN COMPETITION IN A HIGH-POWER CO2-LASER DUE TO OPTOGALVANIC MODULATION OF THE PUMP PROFILE, Optical engineering, 33(1), 1994, pp. 97-101
Experimental evidence of periodic alternation of different transverse
modes in a high-power CO, laser is interpreted in terms of local cooli
ng of the discharge column, which corresponds to the maximum emitted i
ntensity. Optogalvanic coupling between emitted intensity and local di
scharge impedance values yields a transverse redistribution of dischar
ge current and, hence, of laser gain. Thus, besides the fast feedback
provided by the cavity, with high-power lasers one must account also f
or a slow global feedback because of the optogalvanic effects.