Photorefractive Properties of Paraelectric Copper Doped Potassium Tantalate Niobate

The photorefractive properties of Cu doped KTa_1-x Nb_xO₃ have been studied by using two-wave mixing method. The diffraction efficiency reaches as high as 52% under an electric field. The dependences of diffraction efficiency on interference angles and applied fields have been studied. The maximum light induced index change is found to be 2.33 x10^-5 and the photorefraction sensitivity calculated is 5 x 10^-6cm²/J. Experimental results demonstrate that electrons are the dominant charge carriers.