Multiple-image authentication based on metasurface and phase retrieval with sparsity constraints

Abstract

In this paper, a multiple-image authentication method is proposed based on metasurface and phase retrieval with sparsity constraints. In the encryption process, multiple plaintext images are firstly encrypted to a phase-only hologram by using phase retrieval algorithm with sparsity constraints and iterative Fourier transform algorithm, and then the phase-only hologram is converted into a metasurface hologram for multiple-image authentication with the help of a geometric-phase metasurface unit, greatly expanding the encoding information capacity of metasurface for authentication. In the authentication process, the reconstructed image of metasurface hologram is respectively authenticated with multiple plaintext images through nonlinear correlation authentication such that multiple identities of the user holding this metasurface can be simultaneously verified, overcoming the problem that the metasurface for authentication and user identity can only be one-to-one, and substantially improving the efficiency of identity authentication. In order to demonstrate the feasibility of the proposed multiple-image authentication method, a series of numerical simulations are performed, and the simulation results show that the proposed method exhibits high feasibility and security as well as authentication efficiency, and the metasurface for multiple-image authentication has strong robustness against cropping attack.