ElecSus: A program to calculate the electric susceptibility of an atomic ensemble

TL;DR

ElecSus is a computational tool that accurately models the electric susceptibility of alkali-metal vapors, enabling the design of optical devices and analysis of experimental data through spectral calculations and fitting routines.

Contribution

The paper introduces a novel software that calculates electric susceptibility using a matrix Hamiltonian approach for alkali vapors, facilitating optical device design and experimental data analysis.

Findings

Accurately predicts absorption and dispersion spectra of alkali vapors.

Enables design of optical devices like Faraday rotators and filters.

Provides fitting routines for experimental optical data.

Abstract

We present a computer program and underlying model to calculate the electric susceptibility of a gas, which is essential to predict its absorptive and dispersive properties. Our program focusses on alkali-metal vapours where we use a matrix representation of the atomic Hamiltonian in the completely uncoupled basis in order to calculate transition frequencies and strengths. The program calculates various spectra for a weak-probe laser beam in an atomic medium with an applied axial magnetic field. This allows many optical devices to be designed, such as Faraday rotators/filters, optical isolators and circular polarisation filters. Fitting routines are also provided with the program which allows the user to perform optical metrology by fitting to experimental data.