Air-defined Mie voids for photoluminescence control

Spontaneous emission control at the nanoscale is central to quantum photonics, imaging, and optical sensing. However, conventional platforms face intrinsic limitations: plasmonic resonators suffer from strong ohmic losses, while dielectric Mie resonators confine electromagnetic fields inside high-index media, limiting efficient coupling to external emitters. Here, we introduce air-defined Mie voids — complementary cavities etched into silicon — that invert the conventional particle geometry and localize resonant fields predominantly in low-index regions. This configuration enables a loss-minimized and emitter-accessible platform for independent control of excitation enhancement and radiative quantum yield within a single subwavelength structure. We establish a quantitative framework that decouples local-field-driven excitation enhancement from Purcell-mediated emission modulation and validate it through full-wave simulations and experiments on gradient Mie-void arrays. The results demonstrate geometry-dependent emission modulation and strong agreement between theoretical predictions and measured fluorescence intensity. Finally, we realize a multimodal nanophotonic pattern with near–diffraction-limited pixels, where single-void encoding produces distinct optical responses in bright-field, dark-field, and photoluminescence imaging. These findings establish Mie voids as a versatile platform for programmable photoluminescence control, with applications in integrated light sources, high-density optical encoding, super-resolution imaging, and nanoscale sensing.