Elliptical polarization for molecular Stark shift compensation in deep optical traps

TL;DR

This paper demonstrates that elliptical polarization can be used in optical traps to equalize the light shifts of ground and excited rotational states in molecules, enhancing coherence at high intensities.

Contribution

It introduces a method to null differential light shifts in molecular rotational states using specific elliptical polarization configurations.

Findings

Elliptical polarization can match the light shifts of ground and excited states.

The method reduces decoherence caused by trap intensity fluctuations.

Applicable to linear molecules with anisotropic polarizability components.

Abstract

In optical dipole traps, the excited rotational states of a molecule may experience a very different light shift than the ground state. For particles with two polarizability components (parallel and perpendicular), such as linear $^1\Sigma$ molecules, the differential shift can be nulled by choice of elliptical polarization. When one component of the polarization vector is $\pm i\sqrt{2}$ times the orthogonal component, the light shift for a sublevel of excited rotational states approaches that of the ground state at high optical intensity. In this case, fluctuating trap intensity need not limit coherence between ground and excited rotational states.