Speaker
Description
Ultracold gases of divalent atoms excited to high Rydberg states are an exciting tool to explore subjects from fundamental Rydberg physics to quantum simulation [1]. While calcium has received little attention compared to other heavier divalent species (Sr, Yb), its unique features, including low autoionization rates or the smallest electronic affinity of all atomic species, are expected to open up new possibilities to control, manipulate and study Rydberg gases. We will report on the development of an experimental setup for ultracold calcium Rydberg atoms.
Our experimental setup features a custom-made oven combined to a 3D-printed permanent-magnet Zeeman slower, for first stage cooling of calcium atomic beam. Atoms exiting the Zeeman slower at velocities near 30 m/s are then trapped in a magneto-optical trap whose magnetic-field gradient is generated by a pair of home-built coils with an original water-cooling scheme. This approach allows us to prepare a trapped ensemble of Ca atoms at a temperature of a few mK. We then employ a resonant three-photon scheme to excite ground-state atoms to 4snp ¹P and 4snf ¹F Rydberg states. The measurement of the detailed properties of the calcium trap, together with the modelling and characterization of the
Rydberg excitation, is currently under way and will be reported in our communication. With the present setup, we will be in a position to investigate the direct cooling of Rydberg atoms with an isolated core transition [2] or high lying doubly excited "planetary" states of the Ca atom.
[1] Dunning, F. B. et al., J. Phys. B. 49, 112003 (2016).
[2] Bouillon, A. and Marin-Bujedo, E. and Génévriez, M., Phys. Rev. Lett.132, 193402 (2024).
