Double resonance of Raman transitions in a degenerate Fermi gas

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.Comment: 7 pages, 6 figure

Photoassociation spectroscopy of ultracold Yb 173 atoms near the intercombination line

We report on photoassociation (PA) spectroscopy of a degenerate Fermi gas of Yb173 atoms near the dissociation limit of the spin-forbidden S01-P13 intercombination transition. An atom-loss spectrum is measured from a trapped sample for a spectral range down to -1 GHz with respect to the f=5/2→f′=7/2 atomic resonance. The spectrum shows 80 PA resonances, revealing the high nuclear spin nature of the system. To obtain additional information on the excited molecular states, we investigate the Zeeman effect on the spectrum near a detuning of -0.8 GHz and examine the quantum numbers of the Zeeman levels using various two-component spin mixture samples. Finally, we measure the atom-loss rate under PA light for several pronounced PA resonances. © 2018 American Physical Society