Photorefractive effect in Cu- and Ni-doped KNbO3 in the visible and near infrared

Abstract

Nickel- and copper-doped KNbO3 crystals were grown in order to investigate the photorefractive response in the visible and near infrared. Optical absorption, photoconductivity, and two-beam coupling experiments between 515 and 1064 nm are reported. A two-beam coupling constant at 860 nm of 1.4 and 3.2 cm−1 was measured in the nickel- and copper-doped crystals, respectively.