Intrinsic Cavity QED and Emergent Quasi-Normal Modes for Single Photon

TL;DR

This paper introduces a novel cavity design with an embedded two-level atom acting as a tunable semi-transparent mirror, leading to the spontaneous emergence of quasi-normal modes and quasi-bound states in a waveguide system.

Contribution

It presents a new cavity configuration utilizing an atom as an intrinsic mirror, enabling tunable quasi-normal modes and exploring their physical implications.

Findings

Quasi-normal modes emerge spontaneously in the proposed cavity system.

The atomic mirror's reflection coefficient can be tuned via atomic level spacing.

Solid state implementations demonstrate experimental feasibility.

Abstract

We propose a special cavity design that is constructed by terminating a one-dimensional waveguide with a perfect mirror at one end and doping a two-level atom at the other. We show that this atom plays the intrinsic role of a semi-transparent mirror for single photon transports such that quasi-normal modes (QNM's) emerge spontaneously in the cavity system. This atomic mirror has its reflection coefficient tunable through its level spacing and its coupling to the cavity field, for which the cavity system can be regarded as a two-end resonator with a continuously tunable leakage. The overall investigation predicts the existence of quasi-bound states in the waveguide continuum. Solid state implementations based on a dc-SQUID circuit and a defected line resonator embedded in a photonic crystal are illustrated to show the experimental accessibility of the generic model.