Inverse-Designed Metasurfaces Optimize Brightness and Directivity of Micron-Scale Phosphor-Converted Micro-LED Pixels

Metasurface-based phosphor-converted micro-light emitting diodes (micro-LEDs), powered by nanophotonic designs, are rapidly emerging as a key enabler for next-generation near-eye displays─offering compact, energy-efficient, high-brightness emission with built-in directionality without relying on bulky external optics. However, scaling periodic metasurface designs to sub-5 μm footprints─crucial for AR/VR applications─remains a fundamental challenge, as truncation of large-area periodic structures severely degrades optical performance. We introduce a fast inverse design framework that integrates a genetic evolutionary algorithm with a multiple-scattering Green-function solver to optimize scatterer arrangements within a compact 2.5 × 2.5 μm2 pixel footprint. Our optimized designs boost total emission by 25% and forward-directed brightness by 43%, while also enabling programmable control over angular emission profiles, including beaming into application-specific arbitrary solid angles─compared to truncated periodic references. These improvements arise from tailored multiple-scattering interference enabled by structure-factor engineering that extends beyond the single-scattering regime. This computational approach establishes a general strategy for efficient control of incoherent light emission in ultracompact metasurfaces and paves the way toward high-brightness micro-LED pixels with densities exceeding 104 pixels per inch (PPI) resolution, meeting the stringent demands of future display technologies.