We demonstrate the linear transformation of small phase excursions of a spe
ckled wavefront into modulation of the transmitted intensity using the pola
rization self-modulation effect in photoconductive electro-optic crystals.
The technique is more advantageous than the widely used photorefractive two
-wave mixing technique. (C) 2000 American Institute of Physics. [S0003-6951
(00)05352-3].