Real‐Time Tunable Nanoprinting‐Multiplexing with Simultaneous Meta‐Holography Displays by Stepwise Nanocavities

Abstract Although metasurface‐based devices exhibit great potential in optical display and storage technology, the challenges in practical nanoantenna fabrication limit their wide application. In parallel, flat optics, including planar thin‐film nanocavities, have also been extensively studied to realize various spectral engineering and imaging functionalities with large areas and simpler architecture. However, a longstanding practical challenge is to achieve multiplexing imaging functionalities with dynamic switchable ability in real‐time, which to date remains unexplored. In this study, by utilizing the typical inflation sensitivity of hydrogels to humidity change, a multiplexing imaging tunable strategy based on stepwise metal–hydrogel–metal (MHM) nanocavities is originally explored and demonstrated to exhibit dynamic switchable red–green–blue multichannel nanoprinting in real‐time. By decoupling the amplitude/phase correlation, MHM nanocavities successfully enable the hybrid encryption of simultaneous meta‐holography with independent‐encoding freedom in addition to multiplexing nanoprinting. Such an imaging approach, which employs a dynamic tuning scheme, paves a promising avenue toward various applications including state‐of‐the‐art tunable imaging display/storage/encryption, humidity optical sensors, and next‐generation dynamic augmented reality technology.