Highly Efficient and Linearly Polarized Light Emission of Micro-LED Integrated with Double-Functional Meta-Grating.

Linearly polarized micro light-emitting diodes (LP-Micro-LEDs) exhibit exceptional potential across diverse fields. The existing methods to introduce polarization to initially unpolarized Micro-LEDs and to further enhance the degree of polarization are, however, at the expense of low luminous efficiency. We fabricated a GaN-based blue Micro-LED integrated with a Al nanograting and a specially designed Ag/GaN meta-grating, which overcomes the dilemma between the luminous efficiency and polarization degree by simultaneously introducing the effects of mode selection and energy recycling. The fabricated LP-Micro-LED achieves an average polarization extinction ratio (ER) of 21.92 dB within ±60°, showing a 2.04-fold increase in efficiency and a 1.32-fold increase in ER compared to the Ag reflector design. This approach opens the way toward the next generation of high-efficiency and low-cost optoelectronic devices in encryption, displays, optical communication, and medicine.