Spontaneous Emission from a Two-Level Atom in a Rectangular Waveguide

TL;DR

This paper analyzes the quantum behavior of a two-level atom in a rectangular waveguide, focusing on spontaneous emission, mode types, and how detection depends on propagating modes, revealing different decay rates spatially and temporally.

Contribution

It provides a quantum mechanical model of spontaneous emission in a waveguide, distinguishing between propagating and localized modes and their impact on photon detection.

Findings

Detection far from the source depends only on propagating modes.

Spontaneous emission involves both propagating and localized modes.

Different decay rates are observed along space and time in the photon correlation function.

Abstract

Quantum mechanical treatment of light inside dielectric media is important to understand the behavior of an optical system. In this paper, a two-level atom embedded in a rectangular waveguide surrounded by a perfect electric conductor is considered. Spontaneous emission, propagation, and detection of a photon are described by the second quantization formalism. The quantized modes for light are divided into two types: photonic propagating modes and localized modes with exponential decay along the direction of waveguide. Though spontaneous emission depends on all possible modes including the localized modes, detection far from the source only depends on the propagating modes. This discrepancy of dynamical behaviors gives two different decay rates along space and time in the correlation function of the photon detection.