Stimulated Raman scattering in Sr/sub 5/(PO/sub 4/)/sub 3/F laser amplifiers

Summary form only given. Ytterbium-doped Sr/sub 5/(PO/sub 4/)/sub 3/F (S-FAP) has been shown to be a promising laser material for medium-power, high-energy applications such as diode pumped solid-state laser oscillator and amplifier systems. In large-scale amplifier systems where intensities of several GW/cm/sup 2/ are typical, nonlinear optical phenomena such as stimulated Raman scattering (SRS) need to be considered. For our purposes, the error in the calculated gain coefficient is too large (nearly 50%, so we conducted an experiment that directly measured the Raman gain coefficient. A 1053-nm pump beam generated spontaneous Raman light, which was then amplified within the three crystals through stimulated Raman processes. The crystals are separated to prevent oscillation due to Fresnel reflections. Because the 1053-nm pump beam and the SRS signal are collinear after exiting the last crystal, the colors were separated using a prism, and the SRS light detected.