Periodically poled lithium niobate optical parametric amplifiers pumped by high-power passively Q-switched microchip lasers

High-power passively Q-switched microchip lasers produce 157-mu J pulses of l-ns duration in a single-frequency, diffraction-limited output beam. The unfocused 1.064-mu M output of these devices has been used to drive periodically poled lithium niobate optical parametric amplifiers at wavelengths between 1.4 and 4.3 mu m. With a peak conversion efficiency of nearly 1.00%, these devices generate 100-kW, subnanosecond pulses in the mid IR, with a beam quality that is better than two times diffraction limited. (C) 1997 Optical Society of America