SPONTANEOUS OSCILLATION AND SELF-PUMPED PHASE-CONJUGATION IN A PHOTOREFRACTIVE POLYMER OPTICAL AMPLIFIER

Optical processing with photorefractive polymers depends on achieving high optical gain, which depends exponentially on the product of the i nteraction length and the gain coefficient. By use of several polymer layers to increase the overall interaction length and a new high-perfo rmance photorefractive polymer composite, the overall optical one-pass gain becomes as large as a factor of 5. For a two-layer sample placed in an optical cavity made with two concave mirrors, spontaneous oscil lation due to two-beam coupling gain was observed. Because only one pu mping beam is required, this configuration also acts as a self-pumped phase-conjugating mirror with a reflectivity of 13 percent for an appl ied electric field of 75 volts per micrometer, marking a milestone for this growing class of optoelectronic materials.