Photoconductive Enhancement of Degenerate Four-wave Mixing Reflectivity in BSO

Abstract

A method of enhancing the degenerate four-wave mixing (DFWM) conjugate reflectivity in photorefractive BSO is described, which uses an auxiliary beam of different wavelength to modify the local conductivity inside the crystal. With an applied external electric field of 6 kV cm⁻¹, and small diameter DFWM beams, the auxiliary enhancing beam is used to increase local conductivity and hence drop essentially the entire voltage across the small DFWM region producing local fields of ⋍30 kV cm⁻¹. A simple model is derived for three separate experimental configurations, and the predictions are compared with experimental results using yellow and blue beams for DFWM and enhancing beams respectively.