Small-scale self-focusing effects in a high power glass laser amplifier

Experimental data and the results of calculations are presented for the small-scale, self-focusing effects in a high power Nd:glass laser amplifier. Calculations are presented for both perturbed plane waves and nonlinear whole beams. The linear calculations determine transverse beam spectra and 'maximum ripple gain'. Nonlinear calculations model the source of beam imperfections by locating dust particles at several points along the propagation path and by propagating the entire beam through the whole amplifier chain, including the spatial filter. It is noted that the degree of beam degradation depends on the number, size, and location of the noise sources.