Compact neodymium phosphate glass laser emitting 100-J, 100-GW pulses for pumping a parametric amplifier of chirped pulses

A five-stage neodymium phosphate glass amplifier producing 1–1.5-ns radiation pulses of energy up to 110 J is described. The use of a multistage spatial filter based on an aperture line provides efficient extraction of the stored energy. The exit aperture filling factor is 0.65 and the output radiation divergence is equal to three times the diffraction-limited divergence. The energy efficiency of radiation conversion to the second harmonic is 60%. The amplifier is intended for pumping a chirped-pulse optical parametric amplifier.