Continuous Loading of Ultracold Ground-State 85Rb2 Molecules in a Dipole Trap Using a Single Light Beam

Abstract

We have developed an approach to continuously load ultracold $^{85}{{Rb}}{2}$ vibrational ground-state molecules into a crossed optical dipole trap from a magneto-optical trap. The technique relies on a single high-power light beam with a broad spectrum superimposed onto a narrow peak at an energy of about $9400{cm}^{-1}$. This single laser source performs all the required steps the short-range photoassociation creating ground-state molecules after radiative emission, the cooling of the molecular vibrational population down to the lowest vibrational level ${v}{X}=0$, and the optical trapping of these molecules. Furthermore, we probe by depletion spectroscopy and determine that 75% of the ${v}{X}=0$ ground-state molecules are in the three lowest rotational levels ${J}{X}=0$, 1, 2. The lifetime of the ultracold molecules in the optical dipole trap is limited to about 70 ms by off-resonant light scattering. The proposed technique opens perspectives for the formation of new molecular species in the ultracold domain, which are not yet accessible by well-established approaches."

Paulo Cesar Ventura

Postdoctoral fellow

A physicist working with epidemic models in multiscale populations and complex networks.