We propose methods of optical pumping that are applicable to open, high-angular-momentum transitions in atoms and molecules, for which conventional optical pumping would lead to significant population loss. Instead of applying circularly polarized cw light, as in conventional optical pumping, we propose to use techniques for coherent population transfer (e.g., adiabatic fast passage) to arrange the atoms so as to increase the entropy removed from the system with each spontaneous decay from the upper state. This minimizes the number of spontaneous-emission events required to produce a stretched state, thus reducing the population loss due to decay to other states. To produce a stretched state in a manifold with angular momentum $J$, conventional optical pumping requires about $2J$ spontaneous decays per atom; one of our proposed methods reduces this to about ${log}_{2}2J$, while another of the methods reduces it to about one spontaneous decay, independent of $J$.

• Received 31 August 2016

DOI:https://doi.org/10.1103/PhysRevA.94.043416