Optimization of Rhodium-Doped BaTiO3 for High-Power Photorefractive Applications in the Near Infrared

Abstract

Phase conjugation and two-wave mixing in photorefractive crystals are used for frequency locking, power combining and beam cleanup of laser diodes. One requirement for these processes is a high gain or coupling coefficient, which implies a high trap density. For use at high power levels, another important requirement is low absorption, to minimize insertion loss and heating of the crystal. In order to increase the trap density, researchers have doped crystals to higher and higher concentrations.1,2 Unfortunately, this almost always leads to an undesirable increase in absorption coefficient. In this presentation we describe the use of Rh doping3,4 followed by post-growth annealing to produce BaTiO3 crystals with both high trap density and low absorption at 860 nm.