Independent blazed diffraction in a polarization insensitive dual waveband metagrating

Blazed gratings play a vital role in wavelength dispersion and directional beam steering, and the emergence of metasurfaces has opened new opportunities for compact and flexible blazed diffraction devices.However, whether in conventional or metasurface-based implementations, achieving stable and mutually independent wavefront responses under multi-wavelength operation remains a significant challenge.This work presents a metagrating design strategy that enables independent control of blazed diffraction across multiple wavelength bands, providing broadband wavefront manipulation within a single device. By arranging different circularly symmetric nanopillar units in an interleaved manner within a single planar layer and tuning the phase coverage for each wavelength band, multiple blazed diffraction modes can be achieved within a single device, with phase responses remaining independent across different bands. Such all-dielectric metagratings exhibit blazed diffraction behavior consistent with the design across both the visible and near-infrared bands, such all-dielectric metagratings exhibit blazed diffraction behavior consistent with the design across both the visible and near-infrared bands, with more than 90% of the transmitted energy concentrated in the designed diffraction orders. This work provides a compact and scalable design framework for multi-wavelength diffractive optical devices, with potential applications in planar optical systems.