Image encipherment based on optical parallel processing using spatial light modulators

All-optical image coding and decoding are demonstrated for image encipherment communication. The optical parallel coder consists of two cascaded bipolar-operational spatial light modulators (BSLMs) that can select positive and negative image readout in response to the electrical pulse polarity. Coding is performed by an exclusive-OR operation, to a key and an input image, while decoding is the same operation performed to a decoding key and an enciphered image. Coding was performed within a 8-ms duration, which is even faster than the conventional television system. Increasing the voltages to the BSLMs two-fold or three-fold and shortening the pulse durations speed up the processing rate.<>