Self-pumped phase conjugate mirror and method using AC-field enhanced photorefractive effect

摘要

A self-pumped phase conjugate mirror and method is disclosed in which an optical beam is applied to a crystal formed from a photorefractive material, the beam is deflected back into the crystal as a return beam to cross-couple with the input probe beam, and an alternating electric field is applied across the crystal to establish a photorefractive index grating shift of about 90 and bring the crystal gain up to a level at which phase conjugation takes place. By a suitable selection of field strength and frequency, and an angle between the probe and return beams within the crystal of less than about 5 (3 for GaAs) , semiconductor materials with electro-optic coefficients of less than about 10 picometers/volt can be used as the conjugating medium. Such materials have previously not worked in a self- pumped conjugator, but are much more readily available, more responsive, and have improved bandwidths compared to substantially higher electro- optic coefficient refractive materials that have been used in prior inherently self-pumped conjugators.