Theory of single-photon emission from neutral and charged excitons in a polarization-selective cavity

TL;DR

This paper presents a theoretical study of polarized single-photon emission from excitons in asymmetric vertical cavities, proposing configurations for near-perfect polarized efficiency and providing analytical formulas for photon output.

Contribution

It introduces a theoretical framework for optimizing polarized single-photon emission in asymmetric cavities, advancing quantum dot photon source design.

Findings

Identified optimal cavity configurations for polarized photon emission.

Derived analytical formulas linking emission rates to photon polarization output.

Demonstrated potential for near-unity polarized efficiency in single-photon sources.

Abstract

Single-photon sources based on neutral or charged excitons in a semiconductor quantum dot are attractive resources for photonic quantum computers and simulators. To obtain indistinguishable photons, the source is pumped on resonance with polarized laser pulses, and the output is collected in orthogonal polarization. However, for sources featuring vertical emission of light, 50% of the emitted photons are unavoidably lost in this way. Here, we theoretically study the quantum dynamics of an exciton embedded in an asymmetric vertical cavity that favors emission in a specific polarization. We identify the configuration for optimal state initialization and demonstrate a path toward near-unity polarized efficiency. We also derive simple analytical formulas for the photon output in each polarization as a function of the Purcell-enhanced emission rates, which shed light on the physical mechanism behind our results.