On the indistinguishability of Raman photons

摘要

We provide a theoretical framework to study the effect of dephasing on thequantum indistinguishability of single photons emitted from a coherently drivencavity QED $\Lambda$-system. We show that with a large excited-state detuning,the photon indistinguishability can be drastically improved provided that thefluctuation rate of the noise source affecting the excited state is fastcompared with the photon emission rate. In some cases a spectral filter isrequired to realize this improvement, but the cost in efficiency can be madesmall.