Efficient Production of Ground-State Potassium Molecules at Sub-mK Temperatures by Two-Step Photoassociation

A. N. Nikolov; J. R. Ensher; E. E. Eyler; H. Wang; W. C. Stwalley; P. L. Gould

doi:10.1103/PhysRevLett.84.246

Efficient Production of Ground-State Potassium Molecules at Sub-mK Temperatures by Two-Step Photoassociation

A. N. Nikolov, J. R. Ensher, E. E. Eyler, H. Wang, W. C. Stwalley, and P. L. Gould

Phys. Rev. Lett. 84, 246 – Published 10 January 2000

Abstract

We have developed a two-step “ $R$ -transfer” method that efficiently produces translationally ultracold potassium molecules in the $X {}^{1}Σ_{g}^{+}$ electronic ground state. Laser-cooled atoms are initially photoassociated at large internuclear separation $R$ to form molecules in high vibrational levels of the $1 {}^{1}Π_{g}$ state, which are in turn excited by an additional laser to shorter-range Rydberg states such as $5 {}^{1}Π_{u}$ and $6 {}^{1}Π_{u}$ . Subsequent radiative decay produces ground-state molecules at rates up to $10^{5} molecules / second$ per vibrational level.