Abstract

Most diode pumped solid state lasers are Q-switched actively using electrooptic or acoustooptic techniques. In this paper we present a passively Q-switched diode pumped Nd:YAG laser using $F_2^{-}$ color centers in lithium fluoride (LiF) as a saturable absorber. The color centers are created by exposing pure LiF to gamma radiation at room temperature, The resulting $F_2^{-}$ color centers produce a broad absorption band centered at 980 nm with a 180-nm FWHM. The colored LiF crystal is placed in a laser cavity consisting of a single external mirror and a 1-cm long Nd:YAG rod with one end coated as a dichroic high reflector. The laser is end pumped via optical fiber with a laser diode operating at 808 nm. The Q-switched laser produces 20-ns long pulses at 1064 nm, with a pulse energy of up to 10 µJ. The pulse self-repetition rate is 4 kHz when the pump power is 500 mW.

© 1989 Optical Society of America