Linearly polarized LED maximizes polarization degree and luminous efficiency
Linearly polarized LED maximizes polarization degree and luminous efficiency lead image
From secure communications to advanced displays to biomedical diagnostics, linearly polarized LEDs (LP-LEDs) have shown promise for several optoelectronic applications. Despite advances in using single metallic gratings, with double function of surface plasmon-quantum well (SP-QW) coupling and polarization selection, challenges with high-efficiency polarization emission persist, often resulting in a tradeoff between polarization selection and SP-QW coupling.
Combining a silver nanocone metasurface to enhance efficiency with an aluminum nanograting for polarization-selective emission into a dual-structure design, researchers have developed a gallium nitride-based blue LP-LED that mitigates this tradeoff to provide a path forward for high-performance LP-LEDs. The device by Wang et al. effectively addresses the conflict between low luminous efficiency and poor electrical performance.
“Unlike single-layer metallic gratings with dual functionality, the proposed dual-structure design combing metallic grating and SP-enhanced metasurface enables independent control of SP excitation and polarization selection in LEDs,” said Xuzheng Wang. “This design resolves the tradeoff between polarization selection and SP decoupling, thereby maximizing both polarization degree and luminous efficiency.”
The group’s LP-LED demonstrates a 2.5-fold boost in efficiency and 1.24-fold improvement in average polarization extinction ratio compared to conventional silver reflector backside designs, simultaneously optimizing luminous efficiency, electrical performance, and polarization degree.
The silver nanocones also provide improved local density of optical states with efficient coupling at distances up to approximately 100 nanometers, crucially surpassing the typical skin depth of SP-QW coupling.
The group hopes to use their LP-LED high efficiency and polarization ratio to advance metasurface based applications for encryption multiplexing displays.
Source: “Highly efficient linearly polarized LED via surface plasmon integrated with Ag nanocone metasurface,” by Xuzheng Wang, Zhenhuan Tian, Shuheng Pei, Chuangcheng Xu, Jiadong Zhang, Xiaoping Li, Jieming Wei, Ben Jia, Feng Li, Feng Yun, Applied Physics Letters (2025). The article can be accessed at https://doi.org/10.1063/5.0282759 .
