Increase in phase-conjugate reflectivity of a holographic Nd:YAG oscillator due to resonant refractive-index grating

摘要

We have studied both experimentally and numerically the role of resonant refractive-index gratings (RIGs) in a self-pumped phase-conjugate mirror based on an Nd:YAG amplifier with nonreciprocal feedback loop. In experiment the generation of the phase-conjugating laser was delayed with respect to the recording of a holographic nonlinear mirror by an external beam. An increase in the phase-conjugate reflectivity at a delay time of about 3 μs was measured. The numerical calculation confirmed the additional contribution that the resonant RIG formed in a pumped Nd:YAG crystal because of excitation of a higher-lying level of Nd~(3+) ions make to the efficiency of phase conjugation.