Volume holographic optical encryption and decryption in photorefractive LiNbO3:Fe crystal

摘要

We present general volume holographic encryption and decryption system by means of two wave mixing process that can apply to variety of diffraction domains, including the conventional Fourier hologram domain (using 4f -optical processor), the Fresnel hologram domain, and fractional Fourier hologram domain. A rigorous theory for volume holographic encryption and decryption is developed and presented under the framework of Collins diffraction integral formalism. The ability for volume holographic encryption and decryption are successfully demonstrated in a photorefractive LiNbO3:Fe crystal. We also demonstrate a robustness test of our holographic decryption system with respect to misalignment of the phase key in both longitudinal and transversal directions away from the original position and blind decryption without knowledge of the correct key.