Fig. 1
From: Optical coherence encryption with structured random light
Principle of optical coherence-based encryption. a Encoding of an optical image with a transmission function t(v) (plaintext) into the spatial coherence structure W(r1,r2) (ciphertext) of a random light beam through a generalized van Cittert–Zernike theorem formed by a dynamic diffuser and an encoding system with the encryption keys embeded inside. b The generalized Hanbury–Brown Twiss experiment setup for measuring the complex spatial coherence structure. The phase difference between the reference fields is controlled by the phase retarders. c Decoding of the plaintext from the measured spatial coherence structure WR(r1,r2) and the encryption keys via an inverse transfer function of the encoding system