Superradiant emission of a thermal atomic beam into an optical cavity

TL;DR

This paper presents a theoretical analysis of superradiant emission from a thermal atomic beam in an optical cavity, identifying two superradiant phases and their stability, with analytical and numerical insights into linewidth and spectral features.

Contribution

It introduces a semiclassical model for thermal atomic beams in cavities, predicting two distinct superradiant phases and analyzing their stability and spectral properties.

Findings

Identification of steady-state and multi-component superradiant phases.

Analytical expressions for emission linewidth.

Robustness of superradiant phases against spontaneous emission and dephasing.

Abstract

We theoretically analyze the collective dynamics of a thermal beam of atomic dipoles that couple to a single mode when traversing an optical cavity. For this setup we derive a semiclassical model and determine the onset of superradiant emission and its stability. We derive analytical expressions for the linewidth of the emitted light and compare them with numerical simulations. In addition, we find and predict two different superradiant phases; a steady-state superradiant phase and a multi-component superradiant phase. In the latter case we observe sidebands in the frequency spectrum that can be calculated using a stability analysis of the amplitude mode of the collective dipole. We show that both superradiant phases are robust against free-space spontaneous emission and $T_2$ dephasing processes.