Non-mechanical optical beam steering and switching is produced by
optically controlled liquid crystal spatial light modulator with angular
magnification by high efficiency volume Bragg gratings recorded in a
photosensitive PTR glass. Small angle beam deflection in a photoactive
liquid crystal cell is produced by exposing it to a controlling beam from
an external source of radiation with predetermined distribution of power
density which causes predetermined spatial gradients of a refractive
index in a liquid crystal cell and, therefore, refraction of a controlled
beam which is made to propagate in the region with spatial gradient of
the refractive index. Large angle beam deflection is produced by a volume
Bragg grating with angular selectivity adjusted in such way that small
angle scanning produced by optically controlled liquid crystal spatial
light modulator results in change of diffraction efficiency from zero to
100% for switching the beam for two Bragg angles.