Orientation-dependent spontaneous emission rates of a two-level quantum emitter in any nanophotonic environment

TL;DR

This paper theoretically investigates how the spontaneous emission rate of a two-level quantum emitter varies with orientation in different nanophotonic environments, revealing up to 100-fold changes and providing a symmetry-based framework for understanding and controlling emission rates.

Contribution

It introduces a general Green function-based representation of emission rate versus orientation, offering new insights into orientation-dependent emission control in nanophotonics.

Findings

Emission rates vary up to 100 times with orientation.

Green function symmetry determines preferred emission orientations.

Strategies for active emission rate control are proposed.

Abstract

We study theoretically the rate of spontaneous emission of a two-level quantum emitter embedded in realistic systems: near a mirror, near a plasmonic sphere, or in a 3D photonic bandgap crystal. At constant frequency and position, we find striking (up to $10^{2}\times$) variations in emission rate by varying the orientation of the transition dipole moment. We present a general representation of rate versus orientation that only invokes symmetry of the Green function. The concomitant 3-dimensional geometric surfaces provide much insight in how preferred orientations for enhancement (or inhibition) depend on the emitter's frequency and location, and on optimal strategies to actively switch emission rates by controlling oriented dipoles.