SPONTANEOUS FILAMENTATION IN BROAD-AREA DIODE-LASER AMPLIFIERS

The stability of a plane wave propagating in single- and double-pass b road-area diode laser amplifiers is analyzed. It is found that lateral ly periodic perturbations exhibit a longitudinal variation that is a m ixture of exponential growth and periodic oscillation. The latter osci llation has a spatial period related to the Talbot distance. Due to th e interaction between these two effects, double-pass amplifiers become unstable against lateral perturbations, and the field spontaneously c ollapses into a periodic array of filaments. Experimental results are presented that show good agreement with the theoretical analysis.