Physically-Secured Ghost Diffraction and Transmission

A new approach to realizing physically-secured ghost diffraction and transmission is proposed in this letter. A series of random 2D arrays of numbers are used as optical information carriers to transmit original data, e.g., analog signals or images as ghosts. Computer-generated magnification factors are applied for optical data encoding, and physically-generated scaling factors are generated with absorptive filters in free-space optical data transmission. The series of computer-generated magnification factors and physically-generated scaling factors serves as security keys, and is explored to realize high-fidelity and high-security free-space optical data (ghost) transmission. It is experimentally demonstrated that the proposed method is feasible and effective in different environments, i.e., without or with scattering media. The proposed physically-secured ghost diffraction scheme offers a new research perspective on secured optical information (e.g., analog signal) transmission in free space.