Phase-only optical decryption in a planar integrated micro-optics system

We present a compact optical decryption system using the generalized phase contrast (GPC) method implemented in a planar integrated micro-optical (PO) device. An encrypted phase pattern is deciphered by the application of a decrypting phase key and visualized using a miniaturized implementation of the GPC method. The current proof-of-principle demonstration makes use of a PO device composed of diffractive micro-optical elements to form a 4-f lens imaging setup with a spatial phase-only filter at the Fourier plane. Successful decryption of a 17 × 9-pixel encrypted phase mask is achieved with high-contrast visualization of the original pattern.