A Pockels effect light valve: Phototitus applications to optical image processing

An electro-optic light valve was recently described, which uses the Pockels effect in a KD2PO4crystal cooled close to its Curie temperature and is addressed by photoconduction in an amorphous selenium layer. Preliminary performance was: resolution 20 lp/mm, contrast ratio 40/1, writing time 10 µs, sensitivity 100 erg/cm²for 10/1 contrast. The linearity of the Pockels effect allows image addition and subtraction, the latter being obtained by reversing the applied voltage between two exposures. Experiments of first and second order image derivation using incoherent light are described, the latter using subtraction of a blurred image from the initial one.