Investigation of wavefront reversal in a phosphate glass laser amplifier with a 12-cm output aperture

An investigation was made of wavefront reversal (WFR) in a multistage neodymium glass laser amplifier characterized by a small-signal gain of 10⁴ and an output energy up to 450 J for pulses of ~30 nsec duration. A WFR mirror, representing a stimulated Brillouin scattering oscillator-amplifier system, was proposed and investigated under conditions of high radiation energies (up to 4 J). The use of this mirror ensured a high quality of the reversed beam and efficient utilization of the energy stored in the neodymium amplifier. The brightness of the reversed radiation, averaged over the diffraction angle, exceeded 2×10¹⁷ W·cm^–2·sr^–1.