Voltage-controlled photorefractive effect in paraelectric KTa(1-x)Nb(x)O(3):Cu,V

Experimental results that demonstrate the formation of photorefractive gratings in KTN:Cu,V in theparaelectric phase are presented. These gratings are formed using the quadratic electro-optic effect, which allows amplitude modulation of the diffracted beam by an external electric field. High diffraction efficiencies of over 50% in a 3-mmthick sample and amplitude modulation of the diffracted beam by an external field at frequencies of up to 20 kHz were observed.