AC Stark Effect in Ultracold Polar RbCs Molecules

TL;DR

This study explores how off-resonant trapping light influences ultracold RbCs molecules, revealing tunable hyperfine couplings and detailed polarizability measurements crucial for quantum control.

Contribution

It provides the first combined experimental and theoretical analysis of hyperfine-resolved AC Stark shifts and polarizability in ultracold RbCs molecules at 1550 nm.

Findings

Hyperfine structure exhibits rich avoided crossings.

Polarizability characterized with high precision.

Coupling between hyperfine states can be tuned by polarization rotation.

Abstract

We investigate the effect of far-off-resonant trapping light on ultracold bosonic RbCs molecules. We use kHz-precision microwave spectroscopy to measure the differential AC Stark shifts between the ground and first excited rotational levels of the molecule with hyperfine-state resolution. We demonstrate through both experiment and theory that coupling between neighboring hyperfine states manifests in rich structure with many avoided crossings. This coupling may be tuned by rotating the polarization of the linearly polarized trapping light. A combination of spectroscopic and parametric heating measurements allows complete characterization of the molecular polarizability at a wavelength of 1550~nm in both the ground and first excited rotational states.