Photorefractive grating spectroscopy is applied to study the anisotropy of the dielectric permittivity of Sn2P2S6. Two techniques are used, one based on measurements of the amplitude of the space charge field grating as a function of grating spacing and the other based on measurements of the grating decay time. Both techniques provide close values for the anisotropy that appears to be well pronounced. The ratio of the dielectric permittivity in the  and the  direction is estimated to be close to 4. We found that the charge mobility is nearly the same along these two directions.
© 2003 Optical Society of America