Dynamic Waveguides and Gratings in Photorefractive Crystals

Abstract

This chapter is an overview of the photorefractive effect, the important photorefractive nonlinear processes and common photorefractive materials. In Section 2, the formation of steady-state spatial solitons by laser beam propagation through photorefractive crystals (PRC) with optical activity and absorption is theoretically and experimentally described. The spatial soliton features, which characterize the dynamic waveguide built in PRC, are analyzed. The soliton polarisation dynamics reaches a stable behavior under high external electric fields. Two-wave mixing and self-diffraction in dynamic harmonic and inharmonic gratings, induced by lasers in PRC, are presented in Section 3. The diffraction efficiency and beam amplification can reach high values, with promising potential in optical interconnections and storage. Dynamic and adaptive gratings by double phase conjugation (DPC) in PRC are discussed in Section 4. High phase conjugated reflectivity, high coupling transmission efficiency and robust interconnections of mutually incoherent lasers are achieved in DPC using Rh:BaTiO3 crystals.