Phase-change metasurfaces for dynamic image display and information encryption

TL;DR

This paper introduces a phase-change metasurface platform using Sb₂S₃ that enables dynamic control of light for image display and encryption, offering high-capacity, secure data storage with reversible state tuning.

Contribution

The work demonstrates a novel Sb₂S₃-based metasurface capable of active amplitude and phase modulation for dynamic nanoprinting and holography, advancing optical encryption technology.

Findings

Reversible switching between amorphous and crystalline states controls image display.

Multiplexed metasurfaces encode multiple images with polarization decoding.

High-capacity, secure data storage potential demonstrated.

Abstract

Optical metasurfaces enable to engineer the electromagnetic space and control light propagation at an unprecedented level, offering a powerful tool to achieve modulation of light over multiple physical dimensions. Here, we demonstrate a Sb$_{2}$S$_{3}$ phase-change metasurface platform that allows active manipulation of both amplitude and phase. In particular, we implement dynamic nanoprinting and holographic image display through tuning crystallization levels of this phase-change material. The Sb$_{2}$S$_{3}$ nanobricks tailored to function the amplitude, geometric and propagation phase modulation constitute the dynamic meta-atoms in the multiplexed metasurfaces. Using the incident polarizations as decoding keys, the encoded information can be reproduced into a naonprinting grayscale image in the near field and two holographic images in the far field. These images can be switched on and off by taking advantages of the reversible tunability of Sb$_{2}$S$_{3}$ nanostructure between amorphous and crystalline states. The proposed phase-change metasurfaces featuring manifold information and multifold encryption promise ultracompact data storage with high capacity and high security, which suggests an exciting direction for modern cryptography and security applications.