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‐A 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 A in YAG laser crystals.