Holographic recording in photorefractive Bi_2TeO_5 crystals at high intensity

摘要

We report the recording of nearly 35% diffraction efficiency holograms of photorefractive nature in Bi_2TeO_5 crystals, using 633 nm wavelength laser beams. Holographic techniques showed that a slow and a fast holograms arise, the latter based on electrons and the former based on positively charged carriers. We also measured the quantum efficiency for photoelectron generation and the characteristic diffusion (L_d) and Debye (l_s) lengths of these holograms and verified that L_d and l_s are modified as the light intensity onto the crystal increases, in agreement with previously reported theoretical prediction and experimental results but on other photorefractive material.