Gap-surface plasmon based meta-mirror OLED cavities for unified physical length and narrower angular spectral response

Abstract A reflective metasurface that can support the gap-surface plasmon (GSP) mode has been widely applied to various plasmonic structures due to its high-quality-factor magnetic resonance, which is less sensitive to the refractive indices of surrounding materials, and its strong reflection phase control capability. In this work, we applied a 2D nanostripe- and 3D nanodisk-based GSP metasurface to the backside mirror of an organic light-emitting diode (OLED) cavity to provide optimized phase tuning performance with sufficiently high reflection amplitude. Through this analysis, the proposed OLED cavity, supported by the meta-mirror, exhibits a unified physical length across red, green, and blue resonance conditions. Additionally, we analyzed the spectral response of the OLED cavity under various oblique angular conditions, revealing that the GSP-based metasurface with magnetic resonance demonstrates higher angular selectivity compared to a conventional cavity designed with a flat metal mirror.