Enhanced and directional light emission from two-dimensional excitons using Mie voids.

Controlling light emission at the nanoscale has important applications in solid-state lighting, displays, and quantum light sources. Achieving this control requires both enhanced local electromagnetic fields to boost emission intensity and engineered radiation patterns to direct photons efficiently. Mie voids, consisting of an air cavity surrounded by a high-index semiconductor, are particularly suited for this purpose because they expose their strongest fields in an accessible region for nearby emitters while supporting resonances that shape directional emission through interference. Here, we demonstrate an all-van der Waals nanophotonic platform that couples excitons in atomically thin WS2 to Mie void resonators formed in WSe2. Guided by electromagnetic simulations, we identify void geometries that maximize photoluminescence through synergistic enhancement of excitation and emission processes. We also introduce a two-step fabrication approach that leverages van der Waals assembly to independently control the void diameter and depth. Experimentally, we observe up to a 600-fold increase in photoluminescence intensity from monolayer WS2 placed on individual voids compared to unstructured WSe2, along with pronounced out-of-plane beaming of light that yields a forward-to-off-axis enhancement of 2.6 dB. These results establish Mie voids in van der Waals semiconductors as a versatile platform for controlling light-matter interactions at the nanoscale.