Competition between subharmonic and resonating beams for photorefractive gain in bismuth silicon oxide

Two beams incident upon a bismuth silicon oxide crystal are shown to give rise to a subharmonic halfway between the incident beams and to an oscillating beam in a ring resonator. It is further shown that the two beams arising are in competition with each other: the subharmonic power rises when the oscillating beam declines owing to damping of the resonator.