Switchable image displays in tri-channel phase-change metasurfaces

Optical metasurfaces enable to manipulate light fields across multiple physical dimensions, significantly enhancing information density, security, and system integration. Here, we propose a general platform of multi-functional phase-change metasurfaces for dynamic image displays in the visible range, enabled by active manipulation of optical spectrum, amplitude, and phase, leading to threefold dynamic exhibition functions. Through elaborately encoding the tri-channel information using a single-cell metasurface composed of nanobricks, three distinct functions are integrated and the flexibility of dynamic switch is allowed. Leveraging the tunable properties of between amorphous and crystalline states, the switchable displays are realized, including a structural-color image, and grayscale and holographic images with independent-encryption polarization freedom. The proposed metasurfaces open new avenues in multi-functional meta-devices for optical storage, displays, and security applications.