On the indistinguishability of Raman photons

TL;DR

This paper develops a theoretical model to analyze how dephasing impacts the indistinguishability of photons emitted from a cavity QED system, showing that large detuning and fast noise fluctuations can enhance photon quality.

Contribution

It introduces a new theoretical framework for understanding photon indistinguishability under dephasing and proposes conditions for significant improvements.

Findings

Large excited-state detuning improves photon indistinguishability

Fast noise fluctuation rates enhance indistinguishability

Spectral filtering can further improve photon quality with minimal efficiency loss

Abstract

We provide a theoretical framework to study the effect of dephasing on the quantum indistinguishability of single photons emitted from a coherently driven cavity QED $\Lambda$-system. We show that with a large excited-state detuning, the photon indistinguishability can be drastically improved provided that the fluctuation rate of the noise source affecting the excited state is fast compared with the photon emission rate. In some cases a spectral filter is required to realize this improvement, but the cost in efficiency can be made small.