Thermodynamics of a chemical reaction model for the atom-field interaction in a three-level laser

TL;DR

This paper introduces a chemical reaction model to describe the thermodynamics of a three-level laser, providing an intuitive framework for defining photon chemical potential and entropy based on population densities.

Contribution

It offers a novel chemical reaction approach to analyze atom-field interactions and thermodynamic properties in three-level lasers, complementing traditional rate equation methods.

Findings

Defines chemical potential based on population densities

Provides a thermodynamic framework for photon interactions

Enhances understanding of atom-field thermodynamics

Abstract

The temporal evolution of the levels in a three-level laser is macroscopically described by a closed set of rate equations. Here, we complement this picture by providing a model which describes through chemical reactions how the levels are evolving. In most textbooks, the chemical potential is introduced as a concept in quantum statistics. In this paper, we alternatively base its definition on population densities of the excited states in a dopant atom. Then the chemical reaction model delivers a clear and intuitive framework to define the further thermodynamic characteristics of the atom-field interactions such as the chemical potential of the photon and the photon entropy.