Controlling the quantum state of a single photon emitted from a single polariton

TL;DR

This paper explores optimal conditions for transferring a single polariton to a single photon and efficiently detecting it via homodyne measurement, achieving near-perfect efficiencies under realistic experimental parameters.

Contribution

It provides a detailed analysis and optimization of the transfer and detection process of single polaritons to single photons in atomic ensembles.

Findings

High fidelity transfer from polariton to photon is achievable.

Optimal mode matching maximizes homodyne detection efficiency.

Both transfer and detection efficiencies can approach unity.

Abstract

We investigate in detail the optimal conditions for a high fidelity transfer from a single-polariton state to a single-photon state and subsequent homodyne detection of the single photon. We assume that, using various possible techniques, the single polariton has initially been stored as a spin-wave grating in a cloud of cold atoms inside a low-finesse cavity. This state is then transferred to a single-photon optical pulse using an auxiliary beam. We optimize the retrieval efficiency and determine the mode of the local oscillator that maximizes the homodyne efficiency of such a photon. We find that both efficiencies can have values close to one in a large region of experimental parameters.