Experimental demonstration of ghost-imaging-based authentication in scattering media

Optical imaging in scattering media and its applications are challenging and meaningful. In this paper, we propose and experimentally verify a new optical authentication method using structured-detection-based ghost imaging (GI) in scattering media. Object wave is disturbed by multiple diffusers, and then sequentially modulated by a series of random amplitude-only patterns embedded in a spatial light modulator (SLM). The modulated wave passes through another scattering medium, and its intensity is measured by using a single-pixel bucket detector without spatial resolution. During the decryption and authentication, a reference pattern is first retrieved by using all recorded single-pixel intensity signals. Subsequently, a small number of the recorded single-pixel intensity signals are further randomly selected, and a 1-bit compression operation is applied to these selected intensity signals to generate binary signals as ciphertext. The random amplitude-only patterns corresponding to the selected single-pixel intensity signals serve as principal security keys, and wavelength, axial distance and pixel size can serve as supplementary keys. Two strategies are further developed for the decryption and authentication. It is experimentally verified that the proposed method possesses high robustness and high discrimination capability. The proposed method established by using scattering media can significantly enrich optical security, and provides a promising approach for optical authentication.