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

Area of Science:

• Optoelectronics
• Metasurface technology
• Liquid crystal devices

Background:

• Conventional micro-light-emitting diodes (micro-LEDs) emit unpolarized light with Lambertian distribution.
• Controlling micro-LED polarization and directionality typically requires bulky optical components.

Purpose of the Study:

• To propose and numerically investigate a novel micro-LED device integrated with a liquid crystal metasurface (LCM).
• To achieve dynamic control of beam deflection and polarization state in a compact micro-LED.

Main Methods:

• Integration of a subwavelength metallic grating and distributed Bragg reflector (DBR) to form a Fabry-Pérot resonant cavity.
• Incorporation of an electrically tunable liquid crystal metasurface (LCM) for dynamic beam steering.
• Numerical investigation of device performance, including polarization purity, divergence angle, and beam deflection capabilities.

Main Results:

• Achieved highly directional, TE-polarized emission with an extinction ratio >42 dB and divergence angle <25°.
• Demonstrated dynamic beam steering up to 50° using the integrated LCM via an applied electric field.
• Observed low-dispersion characteristics of the proposed micro-LED device.

Conclusions:

• The novel micro-LED integrated with LCM offers dynamic control over emission directionality and polarization.
• The device achieves high optical performance within a compact structure.
• Potential applications include dynamic holographic displays, augmented reality, and advanced optical communication systems.