Optical recording of digital data in PLZT ceramics

Digital data are recorded in nonpolar PLZT ceramics using the photoinduced change of refractive index at wavelength λ=488 nm under applied electric field. This process allows electrical selection and addition of two recorded images and selective optical erasure. It is interpreted in terms of the quadratic electro-optic effect and local electric field amplitudes in the illuminated regions, computed as sums of the applied field and internal screening fields due to displacements and trapping of photoexcited charge carriers.