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

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 Rb-87 atoms. We investigate the 4WM spectra under the application of a strong magnetic field (0.6 T). The Zeeman interaction is strong enough to realize 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.