On‐Chip Integrated Metasurface Empowered Multi‐Channel Multiplexed Three‐Dimensional Hologram

Abstract On‐chip metasurfaces integrated atop optical waveguides have demonstrated the capability of efficiently radiating guided‐waves into arbitrarily prescribed spatial modes by properly tailoring the phase distribution in the metasurface interface. To date, most on‐chip holographic metasurfaces, typically relying on path multiplexing or wavelength multiplexing to multiply the produced images, encounter certain limitations in further enhancing the image storage capacity due to the limited degrees of freedom available for on‐chip devices. This work introduces an on‐chip metasurface composed of polarization‐sensitive cross meta‐atoms allowing independent control of the propagation phase of diffracted waves from waveguided TE and TM modes. Meanwhile, incorporating the guided‐wave generated in‐plane detour phases into the metasurface yields another two degrees of freedom. Thus, four independent holographic images can be readily switched by simply selecting the excitation modes and waveguide ports. As a proof‐of‐concept, a dual‐port four‐channel multiplexed metasurface, whose optical functionalities are validated by performing full‐wave simulations, is successfully realized. Moreover, the application to the creation of 3D holograms is also extended. Thus, the presented method provides a new approach for multifunctional multiplexing of on‐chip metasurfaces, which could hold great potential for applications in next‐generation wearable AR devices, 3D vision, multifunctional micro‐photonic integrated circuits, etc.