Dynamically tunable directional emission from GaN micro-LED enabled by a liquid crystal metasurface

Conventional micro-light-emitting diodes (micro-LEDs) typically emit unpolarized light with a Lambertian distribution and controlling their polarization state and emission directionality usually relies on bulky optical components. We propose and numerically investigate a novel micro-LED device, to our knowledge, integrated with a liquid crystal metasurface (LCM), enabling dynamic control of the beam deflection. By incorporating a subwavelength metallic grating beneath the micro-LED and the distributed Bragg reflector (DBR) on top, a Fabry-Pérot resonant cavity is formed, achieving highly directional TE-polarized emission with an extinction ratio exceeding 42 dB and a divergence angle below 25°, significantly enhancing spatial coherence and polarization purity. Furthermore, an electrically tunable LCM is integrated on top of the DBR, allowing dynamic beam steering via an applied electric field, thus enabling both vertical emission and directional deflection modes within a single device. This metasurface achieves dynamic beam control up to 50° while maintaining a compact structure and high optical performance. Simulation results also indicate that the device exhibits low-dispersion characteristics, highlighting great potential for applications in dynamic holographic displays, augmented reality, and advanced optical communication systems.