Investigations of optical feedback used to enhance stimulated scattering

The technique of using optical feedback to enhance the phase-conjugation process of stimulated Brillouin scattering is experimentally and theoretically investigated. Several feedback arrangements are experimentally studied and demonstrate the ability to reduce significantly the threshold power requirement, enhance the efficiency, and improve the phase-conjugate fidelity of the Brillouin process. Steady-state analytical solutions for the interactions, including the effects of laser pump depletion, are derived. Numerical modeling is used to introduce the more complete transient effects. Good agreement between the experimental results using a pulsed Nd:YAG laser system and the numerical simulations is achieved. The results are applicable, with modification, to other forms of stimulated scattering and also to self-pumped photoreflection.>