# Four-wave mixing in a non-degenerate four-level diamond configuration in the hyperfine Paschen-Back regime

## TL;DR

This paper experimentally investigates four-wave mixing in rubidium vapor under a strong magnetic field that simplifies spectral features, enabling accurate modeling with a four-level system in the hyperfine Paschen-Back regime.

## Contribution

The study demonstrates the effects of a strong magnetic field on four-wave mixing spectra and validates a simple four-level model in the hyperfine Paschen-Back regime.

## Key findings

- Spectral features are simplified under a 0.6 T magnetic field.
- Experimental data agree well with the four-level optical Bloch equations model.
- Hyperfine Paschen-Back regime enables precise spectral analysis.

## Abstract

We present an experimental study of seeded four-wave mixing (4WM) using a diamond excitation scheme (with states from the 5S$_{1/2}$, 5P$_{1/2}$, 5P$_{3/2}$ and 5D$_{3/2}$ terms) in a thermal vapour of $^{87}$Rb atoms. We investigate the 4WM spectra under the application of a strong magnetic field (0.6 T). The Zeeman interaction is strong enough to realise the hyperfine Paschen-Back regime, which has the effect of separating the optical transitions by more than the Doppler width, thereby significantly simplifying the spectral features. We show that this facilitates a quantitative comparison, even in the regime of strong dressing, between experimental data and a simple theoretical model based only on four-level optical Bloch equations.