Effect of using a Bi_12SiO_20 light amplifier on the formation and competition of modes in optical resonators

Abstract
The transverse modes of an oscillator of which the active medium is a Bi12SiO20 (BSO) crystal are expected to be different from those of the passive resonator and of a laser because of the properties of light amplification by photorefractive effect. The experimental study described here demonstrates the possibility of high-diffraction-loss resonators by using a BSO amplifier and illustrates the multimode operation of such an oscillator, according to the Fresnel-number value.