On-Chip Integrated Metasystem with Inverse-Design Wavelength Demultiplexing for Augmented Reality

On-chip optical devices and systems hold great promise for high-performance, versatile, and practical display applications including augmented reality (AR). The recent innovation of metasurface integrated onto on-chip waveguide serves as a new generation of miniature optical components. However, despite its previous endeavors for individual coupler/decoupler, it remains unexplored for full optical integration for bridging the arbitrary encoded input/output conversion between on-chip and free-space light, as well as the component systematic coordination. Here, a fully integrated, on-chip metasystem (FIOM) for AR display is originally realized in the visible regime with customized encoding-freedom. By integrating an inverse-designed metagrating (in-coupler) with wavelength-demultiplexing functionality and two on-chip metasurfaces (out-couplers) onto the waveguide, free-space light with different wavelengths is coupled by the metagrating to opposite propagation directions along the waveguide and subsequently extracted by on-chip metasurfaces to project two customized holographic images. Such a far-field display is uniquely free from zeroth-order diffraction interference due to the on-chip scheme, thus showcasing its AR observation potential in a real-world scene. Overall, the proposed FIOM provides a programmable platform for fully bridging the gaps between free space and guided waves and suggests a feasible route for wearable AR displays, multiplexing optical displays, multicolor compatible devices, etc.