Large optical forces on a barium monofluoride molecule using laser pulses for stimulated absorption and emission: A full density-matrix simulation

TL;DR

This study demonstrates that using laser pulses for stimulated absorption and emission significantly enhances optical forces on BaF molecules, enabling effective separation for electron EDM measurements.

Contribution

It introduces a full density-matrix simulation showing large optical forces with laser pulses, surpassing continuous-wave methods for molecular deflection.

Findings

Laser pulse scheme produces nearly ten times larger force than continuous-wave methods.

The force-to-spontaneous-decay ratio is over ten times higher with pulsed lasers.

Simulations indicate feasible large deflections for molecular separation in EDM experiments.

Abstract

A full density-matrix simulation is performed for optical deflection of a barium monofluoride (BaF) beam. Pairs of counter-propagating laser pulses are used for stimulated absorption followed by stimulated emission. The scheme produces a force which is nearly an order of magnitude larger than that obtainable using continuous-wave laser deflection, and yields a force-to-spontaneous-decay ratio which is more than an order of magnitude larger. The large reduction in spontaneous decay is key to optical deflection of molecules, where branching ratios to other vibrational states do not allow for cycling transitions. This work is part of an effort by the EDM$^3$ collaboration to measure the electric dipole moment of the electron using BaF molecules embedded in a cryogenic argon solid. Deflection of BaF molecules will separate them from the other ablation products coming from a buffer-gas-cooled ablation source, before embedding them into the argon solid. Our simulations show that sufficiently large deflections for this separation are feasible.