Picosecond photorefractive effect in BaTiO(3)

We report the observation of photorefractive index gratings written and read out in BaTiO(3) using single pulses of 30-psec duration and fluences of 1 to 15 mJ/cm(2) at a wavelength of 0.532 microm. While the photorefractive gratings are masked during formation by large free-carrier grating, they are clearly seen from 50 psec to many minutes following the peak in the writing beams. The rapid and complete formation of the photorefractive grating and the complete decay of the free-carrier grating on a scale of 50 to 100 psec indicate either that the carrier-recombination time in our sample of BaTiO(3) is less than 100 psec or that the mobility of the carriers is >23 cm(2)/V sec.