Tunable phase-change metasurfaces for integrated display and encryption: dual near-field nanoprinting and single far-field holography

Abstract Metasurfaces provide an innovative platform for optical encryption, enabling precise manipulation of the polarization state, amplitude, and phase of electromagnetic waves. In particular, multiplexing holography and nanoprinting channels are a promising strategy for achieving multi-image display on metasurfaces. However, conventional static metasurfaces suffer from limited security in image multiplexing. In this work, we propose a multi-channel multiplexed metasurface employing the phase-change material Sb 2 S 3 , which enables dynamic image display and optical encryption by modulating its crystallization state. Specifically, at an operating wavelength of 630 nm, two near-field nanoprinting channels are realized based on the principle of degeneracy, while an additional far-field holographic channel is introduced through tailoring the phase distribution via an optimization algorithm. By actively tuning the crystallization state of the phase-change material, individual channels can be selectively deactivated, thereby achieving optical encryption. The proposed metasurface, featuring multi-image multiplexing and optical encryption, offers high capacity and enhanced security, making it highly encouraging for ultra-compact image display and secure optical information processing.