Isotropic Magnetic Purcell Effect

TL;DR

This paper introduces an isotropic magnetic Purcell effect in silicon and GaP nanocavities, enabling orientation-independent emission enhancement with high quantum yield, robust against small emitter displacements.

Contribution

It presents the concept of an isotropic magnetic Purcell effect with high Purcell factors and quantum yield, independent of emitter orientation, in asymmetric nanocavities.

Findings

Purcell factors around 300 achieved

Quantum yield exceeds 80%, nearly reaching 100% with GaP nanocavities

Effect is robust against 10 nm emitter displacement

Abstract

Manipulating the spontaneous emission rate of optical emitters with all-dielectric nanoparticles benefits from their low-loss nature and thus provides relatively large extrinsic quantum yield. However, such Purcell effect greatly depends on the orientation of the dipole emitter. Here, we introduce the concept of isotropic magnetic Purcell effect with Purcell factors about 300 and large extrinsic quantum yield (more than 80%) for a magnetic dipole emitter of arbitrary orientation in an asymmetric silicon nanocavity. The extrinsic quantum yield can be even boosted up to nearly 100% by utilizing a GaP nanocavity. Isotropy of the Purcell factor is manifested via the orientation-independent emission of the magnetic dipole source. This isotropic Purcell effect is robust against small displacement of emitter on the order of 10 nm, releasing the requirement of precise alignment in experiments.