PHOTOREFRACTIVE 2-STEP RECORDING IN A PIEZOELECTRIC LA3GA5SIO14 CRYSTAL DOPED WITH PRASEODYMIUM

The first experimental verification to the authors' knowledge of effic ient two-step recording in a photorefractive and piezoelectric crystal of La3Ga5SiO14:Pr3+ with cw laser light (I < 20 W/cm(2)) is reported. We found nonlinear behavior of the photorefractive sensitivity and ph otovoltaic current, indicating that the excitation process is connecte d to excitation of 4f(2) electrons of the Pr3+ dopant through an inter mediate level to the conduction band. This two-step nature of the phot orefractive effect makes the crystal an exciting new candidate for app lications in holographic storage. (C) 1998 Optical Society of America.