Polarization correlated photons from a positively charged quantum dot

TL;DR

This paper demonstrates polarization-correlated photon emission from a positively charged quantum dot, with enhanced effects under magnetic fields, and suggests cavity-QED can improve emission coherence.

Contribution

It provides experimental evidence of polarization correlation in a charged quantum dot and proposes a method to enhance coherence via cavity-QED.

Findings

Photon polarization correlation observed without magnetic field

Correlation strength increases with magnetic field

Electron dephasing explained by nuclear Overhauser field

Abstract

Polarized cross-correlation spectroscopy on a quantum dot charged with a single hole shows the sequential emission of photons with common circular polarization. This effect is visible without magnetic field, but becomes more pronounced as the field along the quantization axis is increased. We interpret the data in terms of electron dephasing in the X+ state caused by the Overhauser field of nuclei in the dot. We predict the correlation timescale can be increased by accelerating the emission rate with cavity-QED.