Effective Faraday interaction between light and nuclear spins of Helium-3 in its ground state: a semiclassical study

TL;DR

This paper develops a semiclassical model describing the interaction between light and nuclear spins of helium-3 atoms, deriving effective coupling constants and comparing simplified and full models for different detuning configurations.

Contribution

It introduces a simplified three-spin model for helium-3 light interaction and analytically derives effective coupling constants for specific detuning configurations.

Findings

Effective coupling constants are analytically obtained.

Simplified model agrees with full model predictions.

Two configurations show dominant contributions from different metastable levels.

Abstract

We derive the semiclassical evolution equations for a system consisting of helium-3 atoms in the $2^3S$ metastable state interacting with a light field far-detuned from the $2^3S-2^3P$ transition, in the presence of metastability exchange collisions with ground state helium atoms and a static magnetic field. For two configurations, each corresponding to a particular choice of atom-light detuning in which the contribution of either the metastable level $F=1/2$ or $F=3/2$ is dominant, we derive a simple model of three coupled collective spins from which we can analytically extract an effective coupling constant between the collective nuclear spin and light. In these two configurations, we compare the predictions of our simplified model with the full model.