Spin Selective Purcell Effect in a Quantum Dot Microcavity System

TL;DR

This paper demonstrates spin-selective Purcell enhancement in a quantum dot-micropillar cavity system, enabling highly polarized light emission and advancing quantum light source development.

Contribution

The study introduces a method to selectively enhance quantum dot exciton spin states using magnetic tuning and cavity coupling, with quantitative agreement from a theoretical model.

Findings

26-fold increase in emission intensity for spin-up state

Circular polarization degree up to 93% achieved

Quantitative agreement with a four-level rate equation model

Abstract

We demonstrate the selective coupling of a single quantum dot exciton spin state with the cavity mode in a quantum dot-micropillar cavity system. By tuning an external magnetic field, the Zeeman splitted exciton spin states coupled differently with the cavity due to field manipulated energy detuning. We found a 26 times increase in the emission intensity of spin-up exciton state with respect to spin-down exciton state at resonance due to Purcell effect, which gives rise to the selective enhancement of light emission with the circular polarization degree up to 93%. A four-level rate equation model is developed and quantitatively agrees well with our experimental data. Our results pave the way for the realization of future quantum light sources and the quantum information processing applications.