Bragg reflection by a gain medium optically pumped in a grating geometry

The utilization of Bragg reflection caused by a grating-like pump intensity distribution in a laser-pumped laser amplifier is analyzed theoretically. In the amplifier, an incident laser beam is split into a transmitted and reflected beam, both of which are amplified. We explicitly take into account the interference between the transmitted and reflected beam and the effect of the interference on the saturated gain. We determine the reflective conversion efficiency of such an amplifier and show that if the gain grating is accompanied by a pump-heating-induced refractive-index grating, the reflective conversion efficiency may approach 100 percent.