Phase-only optical decryption of a fixed mask.

TLDR: A compact experimental system is constructed that uses a 635-nm diode laser in which a fixed encrypted 0/pi binary phase mask is decrypted by a binary phase key produced electronically on the spatial light modulator.

Abstract: We present a system for the implementation of phase-only optical decryption of an encrypted fixed phase mask. We achieve decryption by superimposing a decrypting phase key, implemented on a phase-only spatial light modulator with an encrypted phase mask in two equivalent image planes in an optical system. The decrypted phase information is retrieved by the generalized phase-contrast technique. We have constructed a compact experimental system that uses a 635-nm diode laser in which a fixed encrypted 0/pi binary phase mask is decrypted by a binary phase key produced electronically on the spatial light modulator. The key is aligned by electronic scrolling of its position with respect to the mask.