Self-Pumped Phase Conjugation in Barium Titanate with High Intensity Nanosecond Pulses

Abstract

An investigation of self-pumped phase conjugation in barium titanate is made using nanosecond pulses (15 ns) derived from a repetitively pulsed (10 Hz) and frequency-doubled Nd:YAG laser system (532 nm wavelength). It is experimentally shown that high reflectivity (> 20 %) can be achieved. It is also shown that there is a progressive decrease in the reflectivity of both the corner-pumped and ring-passive geometries at pulse intensities of > 4 MW/cm2. At these intensity levels a high photo-carrier population is induced, altering the relative concentrations of Fe2+ and Fe3+ centres and leading to a strong intensity-dependent competition between hole and electron photoconductivity.