All Optical Scheme for Strongly Enhanced Production of Dipolar Molecules in the Electro-Vibrational Ground State

TL;DR

This paper proposes an all-optical method to significantly enhance the production of heteronuclear dipolar molecules in their electro-vibrational ground state through quantum interference effects in two-color photoassociation.

Contribution

It introduces a novel scheme utilizing quantum interference in two-color photoassociation to improve ground state molecule formation, analyzing dependence on laser parameters.

Findings

Enhanced production of ground state molecules via quantum interference.

Dependence of molecule formation efficiency on laser detuning and intensity.

Limited regime for coherent conversion near the free-bound resonance.

Abstract

We consider two-color heteronuclear photoassociation of atoms into dipolar molecules in the J=1 electro-vibrational ground state, where a free-ground laser couples atoms directly to the ground state and a free-bound laser couples the atoms to an electronically-excited state. This problem raises an interest because heteronuclear photoassociation from atoms to near-ground state molecules is limited by the small size of the target state. Nevertheless, the addition of the excited state creates a second pathway for creating ground state molecules, leading to quantum interference between direct photoassociation and photoassociation via the excited molecular state, as well as a dispersive-like shift of the free-ground resonance position. Using LiNa as an example, these results are shown to depend on the detuning and intensity of the free-bound laser, as well as the semi-classical size of both molecular states. Despite strong enhancement, coherent conversion to the LiNa electro-vibrational ground state is possible only in a limited regime near the free-bound resonance.