Broadband beam deflector for GaN based micro-LED with a phase-gradient metasurface in entire visible spectrum

Metasurfaces with subwavelength structures are good candidates for beam manipulation which are usually working at a narrow bandwidth with high coherence. Here, we demonstrate a broadband beam deflector for GaN based micro-LED, utilizing a phase-gradient metasurface in conjunction with a resonant cavity. The beam deflector works at the entire visible spectrum, achieving deflection angles from 9° to 18°, with beam efficiencies of approximately 20% to 35%. This miniature structure is well-suited for applications such as full-color display, naked-eye three-dimensional display, and head-up display. It will facilitate the development of GaN based micro-LEDs with complex optical functionalities.