Unveiling the Enhancement of Spontaneous Emission at Exceptional Points

TL;DR

This paper experimentally verifies the enhancement of spontaneous emission at exceptional points in photonic structures, confirming theoretical predictions and discussing practical limitations for applications in quantum sensing and imaging.

Contribution

The study provides experimental validation of emission enhancement at exceptional points and explores practical limitations due to material loss.

Findings

Confirmed quadratic scaling of emission rate enhancement at EPs

Demonstrated practical limitations caused by material loss

Validated theoretical models with experimental photoluminescence data

Abstract

Exceptional points (EPs), singularities of non-Hermitian physics where complex spectral resonances degenerate, are one of the most exotic features of nonequilibrium open systems with unique properties. For instance, the emission rate of quantum emitters placed near resonators with EPs is enhanced (compared to the free-space emission rate) by a factor that scales quadratically with the resonance quality factor. Here, we verify the theory of spontaneous emission at EPs by measuring photoluminescence from photonic-crystal slabs that are embedded with a high-quantum-yield active material. While our experimental results verify the theoretically predicted enhancement, it also highlights the practical limitations on the enhancement due to material loss. Our designed structures can be used in applications that require enhanced and controlled emission, such as quantum sensing and imaging.