Two-step photorefractive hologram recording in LiNbO3:Fe

Abstract
Holographic recording experiments are performed in iron-doped photorefractivc LiNbO3 using twostep (light wavelengths λ = 1064 nm and λ = 532 nm) excitations. Variations of Fe2+ concentration and light intensity show that two-step excitations via an excited Fe2 state are responsible for the large holographic sensitivity. The experimental results indicate that the dominant charge driving force is the photovoltaic effect.