COMPETITION BETWEEN SUBHARMONIC AND SIGNAL BEAMS FOR PHOTOREFRACTIVE GAIN IN BSO WITH 2 PUMP BEAMS

It is shown that two pump beams incident upon a bismuth silicon oxide crystal give rise to a subharmonic beam bisecting the pump beam. Simultaneously a signal beam injected between the pump beams may be strongly amplified at the expense of the pump beams. It is shown that the amplified signal beam grows with a faster time constant than the subharmonic beam and that there is competition for gain in the steady state regime.