Cavity-assisted spontaneous emission as a single-photon source: Pulse shape and efficiency of one-photon Fock state preparation

TL;DR

This paper analyzes the quantum state of photons emitted from a two-level atom in a high-Q cavity, focusing on pulse shape and efficiency of generating single-photon Fock states, using exact quantum electrodynamics.

Contribution

It provides a detailed quantum electrodynamics analysis of photon emission, including wave packet shape and efficiency, bridging intracavity and free-space field descriptions.

Findings

Determined the spatio-temporal shape of emitted wave packets.

Calculated the efficiency of one-photon Fock state preparation.

Connected quantum noise theories with cavity-emitted photon states.

Abstract

Within the framework of exact quantum electrodynamics in dispersing and absorbing media, we have studied the quantum state of the radiation emitted from an initially in the upper state prepared two-level atom in a high-$Q$ cavity, including the regime where the emitted photon belongs to a wave packet that simultaneously covers the areas inside and outside the cavity. For both continuing atom--field interaction and short-term atom--field interaction, we have determined the spatio-temporal shape of the excited outgoing wave packet and calculated the efficiency of the wave packet to carry a one-photon Fock state. Furthermore, we have made contact with quantum noise theories where the intracavity field and the field outside the cavity are regarded as approximately representing independent degrees of freedom such that two separate Hilbert spaces can be introduced.