Controlling the ac Stark effect of RbCs with dc electric and magnetic fields

TL;DR

This paper studies how static electric and magnetic fields influence the ac Stark shifts in ultracold RbCs molecules, revealing methods to control these shifts via external fields and laser polarization.

Contribution

It demonstrates that electric fields can decouple nuclear spins from rotational motion, enabling control of the ac Stark effect through laser polarization angle.

Findings

Electric fields decouple nuclear spins from rotation, simplifying the Stark effect.

Measured isotropic and anisotropic polarizability components at 1064 nm.

Observed two-photon transitions near the trapping wavelength.

Abstract

We investigate the effects of static electric and magnetic fields on the differential ac Stark shifts for microwave transitions in ultracold bosonic $^{87}$Rb$^{133}$Cs molecules, for light of wavelength $\lambda = 1064~\mathrm{nm}$. Near this wavelength we observe unexpected two-photon transitions that may cause trap loss. We measure the ac Stark effect in external magnetic and electric fields, using microwave spectroscopy of the first rotational transition. We quantify the isotropic and anisotropic parts of the molecular polarizability at this wavelength. We demonstrate that a modest electric field can decouple the nuclear spins from the rotational angular momentum, greatly simplifying the ac Stark effect. We use this simplification to control the ac Stark shift using the polarization angle of the trapping laser.