GaAs diode-pumped Nd : YAG laser

Using a single chip heterostructure GaAs laser diode as a pump source, and temperature tuning its output wavelength to achieve a spectral overlap with the 8680-Å absorption line in Nd : YAG, lasting was observed in a 1.5-mm-diam×25.4-mm-long laser rod. Pump light was directed through a special multilayer dielectric coating on one end of the laser crystal. This coating was designed to transmit 90% of the GaAs light, but still reflect internally 99.9% of the YAG laser light at 1.06 μ. The purpose of the end-pumping technique was to maximize the single-pass absorption of GaAs pump light by making the effective optical path within the laser rod as long as possible, thus compensating for the relatively weak absorption at 8680 Å in YAG laser crystals.