Abstract

Although the existence of nonlinear holographic response in phoforefractive materials has been experimentally observed and its presence treated in some theoretical detail,¹ standard holographic recording techniques have yielded higher-order grating components substantially weaker than the fundamental linear component. Using the unstationary running wave technique of Huignard and Marrakchi,² however, we show that these higher grating harmonics may be substantially increased in strength. Furthermore, this enhancement is selective in that there are distinct criteria for the optimal amplification of each grating order. In addition to a theoretical analysis of this effect, we present experimental verification using photorefractive Bi₁₂SiO₂₀ crystals. By measuring the diffraction efficiency of both the fundamental and second harmonic grating components, we observed substantial enhancement of this nonlinear second-order response with respect to the fundamental.

© 1987 Optical Society of America