Modelling spatio-temporal dynamics of chiral coupling of quantum emitters to light fields in nanophotonic structures

TL;DR

This paper introduces a theoretical model coupling quantum emitters with electromagnetic fields in nanophotonic structures using FDTD simulations, revealing how position and polarization influence chiral light excitation and backcoupling effects.

Contribution

The authors develop a novel framework integrating density matrix formalism with FDTD to simulate chiral light-matter interactions in nanostructures, enabling detailed spatio-temporal analysis.

Findings

Asymmetric light excitation depends on emitter position and polarization.

Backcoupling leads to strongly asymmetric light fields.

Model applied to dielectric waveguide and optical circulator.

Abstract

A quantum emitter placed in a nanophotonic structure can result in non-reciprocal phenomena like chiral light excitation. Here, we present a theoretical model to couple circularly polarized emitters described by the density matrix formalism to the electromagnetic fields within a finite-difference time-domain (FDTD) simulation. In particular, we discuss how to implement complex electric fields in the simulation to make use of the rotating wave approximation. By applying our model to a quantum emitter in a dielectric waveguide and an optical circulator, we show how the excitation of the quantum system depends on its position and polarization. In turn, the backcoupling can result in strongly asymmetric light excitation. Our framework and results will help better understand spatio-temporal dynamics of light field in nanophotonic structures containing quantum emitters.