Dynamics of a two-level system in a broadband light field

TL;DR

This paper derives analytical solutions for a two-level system interacting with broadband light, focusing on Lorentzian spectral density and monochromatic limits, to understand nonlinear polarizability.

Contribution

It provides the first analytical solutions of optical Bloch equations for broadband light interaction with a two-level system, including nonlinear polarizability expressions.

Findings

Analytic solutions for broadband light interaction

Expression for nonlinear polarizability with Lorentzian spectrum

Analysis of monochromatic light limit

Abstract

We provide analytic solutions of the optical Bloch equations for a two-level system interacting with a broadband light field. We will focus on two special examples: incident light with a Lorentzian spectral density and the limit of incident monochromatic light. The results are used to obtain an expression for the nonlinear polarizability of a two-level atom irradiated by a wave with a Lorentzian spectral density.