On-Chip Meticulous Grayscale High-Resolution Meta-Display

On-chip integrated meta-optics hold great promise in creating high-performance and ultracompact optical display devices. Although previous on-chip metasurfaces for meta-display have predominantly enabled binary-image near-/far-field exhibition functionalities, this remains a challenge and has not been fully explored to induce multiple intensity levels for meticulous grayscale images in an on-chip integrated scheme. Here, we propose and experimentally demonstrate a practical approach to embed a high-resolution grayscale image display into an on-chip metasurface integrated on a waveguide in the visible regime. By employing the on-chip meta-diatom interference at the nanoscale, continuous intensity levels of the local optical scattering can be modulated for the out-coupling lightwave to create a high-resolution (pixel size of 440 × 440 nm2) and broadband meticulous grayscale image display. Moreover, directional-selective dual-channel grayscale displays are further expanded by spatially hybridizing the meta-diatom interferences along both x-/y-directions and jointly storing two grayscale images into a single on-chip metasurface pattern. Owing to the on-chip optical propagation scheme, the captured meticulous grayscale display with high fidelity enjoys a high signal-to-noise ratio and large dynamic range uniquely due to zeroth-order diffraction being interference-free. We envision that the proposed meticulous grayscale meta-display driven by an on-chip guided wave allows for their miniaturized integration and promises high-density information storage/encryption, next-generation high-quality miniature displays, and future virtual/augmented reality functionalities.