Effect of Strong Pump Depletion on Two-beam Coupling in Photorefractive BaTiO₃at 442 nm

Abstract

Photorefractive BaTiO 3 crystal illuminated at 442 nm gives a large initial scattering level, which leads to strong pump depletion into beam fanning . Studies on the time development of beam fanning show a temporal shift of the fanned beam maximum towards the c-axis direction . The effect on the signal beam amplification of the strong pump depletion into beam fanning has been investigated, revealing different temporal development of the amplified signal for various cross-angles . Our observations on beam fanning in the presence and in the absence of a signal reveal that there is appreciable coupling between the fanned beam and the signal .