2026 / ACS Photonics

Anomalous spontaneous emission enhancement by bound states in the continuum in nonlocal metasurfaces

First author

Research overview

Problem

An emitter in a periodic structure excites many Bloch modes. Can the high-Q intuition of a single cavity explain their collective contribution to spontaneous emission?

Mechanism

A unified temporal coupled-mode framework integrates over momentum space to evaluate Purcell and photoluminescence factors separately, including collective interactions among non-Hermitian modes.

Result

Theory and full-wave simulations show stronger spontaneous emission in lower-Q regimes near BICs in nonlocal dielectric metasurfaces with comparable effective mode volumes. In the studied system, enhancement varies inversely with Q and the spectra depart from Lorentzian/Fano-like profiles.