Ultrabright and Ultrasmall Chiral Luminescence Pixel Based on Thorned‐Helicoid‐on‐Mirror

Abstract Achieving highly circularly polarized luminescence has long been a primary objective in the design, synthesis, and application of chiral luminophores. However, a persistent challenge arises from the trade‐off between large luminescence dissymmetry factors ( g lum ) and high luminescence efficiency, resulting in typically mediocre brightness for most chiral emitters and limiting their practical use. While various strategies have been proposed to enhance g lum , these values rarely exceed 1.0 and often come at the cost of diminished luminescence intensity. In this article, an extreme nanophotonic approach is employed using thorned helicoid‐on‐mirror (THoM) constructs to generate intense local optical chirality, which is then coupled to achiral dyes with high quantum yields. An efficient coupling is revealed between the strong superchiral near field and the dyes within the chiral nanocavity, which not only produces g lum values exceeding 1.0 but also amplifies both excitation and emission processes via a pronounced chiral Purcell effect, leading to ultrahigh brightness in circularly polarized luminescence. By adjusting the dye assembly and its corresponding emission peaks, tunable chiral emission is achieved, demonstrating significant potential for advanced chiral displays and information encryption. Furthermore, this high‐performance chiral emitting system holds promise for on‐chip integration of chiral lasers and chiral single‐photon sources.