Dynamic bulk photovoltaic effect in photorefractive barium calcium titanate

Oscillating photocurrents are generated in a photorefractive iron-doped bar ium calcium titanate crystal (Ba0.77Ca0.23TiO3; BCT) by illumination with a n oscillating interference pattern. Non-steady-state photocurrents arise us ually from the interaction of a space-charge field with an oscillating phot oconductivity pattern. However, a second-harmonic signal of the oscillating photocurrents is observed in BCT, which is present without any space-charg e field. The main features of the new effect can be explained by considerat ion of a dynamic, i.e., time-dependent, bulk photovoltaic effect. The effec t might be useful for optically addressed memories or optical correlators. (C) 1999 Optical Society of America [S0740-3224(99)01710-5].