Marek Haruza

Luminorefrigeration: vibrational cooling of NaCs

We demonstrate the use of optical pumping of kinetically ultracold NaCs to cool an initial vibrational distribution of electronic ground state molecules X(1)Σ(+)(v ≥ 4) into the vibrational ground state X(1)Σ(+)(v=0). Our approach is based on the use of simple, commercially available multimode diode lasers selected to optically pump population into X(1)Σ(+)(v=0). We investigate the impact of the cooling process on the rotational state distribution of the vibrational ground state, and observe that an initial distribution, J(initial)=0-2 is only moderately affected resulting in J(final)=0-4. This method provides an inexpensive approach to creation of vibrational ground state ultracold polar molecules.

Lumino-Refrigeration: Deep Cooling Polar Molecules by Optical Pumping

Our ability to laser cool atoms depends on the availability of a closed-cycling transition that allows many successive photons to be scattered by the atom. By comparison, molecules have a richer internal structure that is an asset and a liability. It offers new degrees of freedom for exciting experiments but precludes a simple scheme for molecular laser cooling.