Abstract

A novel diode pumping scheme permits a new generation of highly efficient Wavelength-converted laser systems. The basic laser unit, shown schematically in Fig. 1, produces up to 7 W in a low-divergence (M² ~1.8) output at 1 μm. The pump source is two nominally-5-W diode bars, producing a combined power of 13.5 W. The Nd:YAG laser crystals are cut for Brewster-angle propagation, which expands the laser mode in one dimension so as to better match the elliptical pump volume. A rotator placed between the laser crystals corrects thermal birefringence, allowing efficient polarized operation. The electrical efficiency is 12%, but conductive cooling with thermoelectric coolers and fan-forced air reduces this to an overall wall-plug efficiency of 8%. The laser output is cw, but it can also be Q-switched with an acousto-optic modulator at pulse repetition frequencies from 1 to 20 kHz. This laser is the enabling technology for a number of wavelength-conversion schemes.

© 1995 Optical Society of America