Binary phase spatial modulation using photoinduced anisotropy in amorphous As(2)S(3) thin film

We present a method for binary phase spatial modulation that uses photoinduced anisotropy in a chalcogenide amorphous As(2)S(3) thin film and its application to binary phase-only filters in a VanderLugt optical correlator. The time-dependent light-transmission properties of the photoilluminated As(2)S(3) thin film are analytically examined by use of third-order nonlinear polarization theory. Experimental results on optical correlation are discussed.