# Double resonance of Raman transitions in a degenerate Fermi gas

## TL;DR

This paper investigates the momentum-resolved Raman spectra of a spin-polarized degenerate Fermi gas of ytterbium-173 atoms, revealing double resonance phenomena and spectral splitting explained by the Autler-Townes effect, consistent with spinful band structure.

## Contribution

It demonstrates the observation of double resonance and spectral splitting in Raman spectra of a Fermi gas, linking experimental results to the theoretical spinful band structure under effective magnetic fields.

## Key findings

- Double resonance of Raman transitions observed at specific magnetic fields.
- Spectral splitting explained by the Autler-Townes effect.
- Results consistent with the spinful band structure in the system.

## Abstract

We measure momentum-resolved Raman spectra of a spin-polarized degenerate Fermi gas of $^{173}$Yb atoms for a wide range of magnetic fields, where the atoms are irradiated by a pair of counterpropagating Raman laser beams as in the conventional spin-orbit coupling scheme. Double resonance of first- and second-order Raman transitions occurs at a certain magnetic field and the spectrum exhibits a doublet splitting for high laser intensities. The measured spectral splitting is quantitatively accounted for by the Autler-Townes effect. We show that our measurement results are consistent with the spinful band structure of a Fermi gas in the spatially oscillating effective magnetic field generated by the Raman laser fields.