Optimal trapping wavelengths of Cs$_2$ molecules in an optical lattice

TL;DR

This paper identifies optimal 'magic' wavelengths for trapping Cs₂ molecules in optical lattices, facilitating efficient transfer to ground states for quantum gas creation.

Contribution

It calculates dynamic polarizabilities of Cs₂ molecules and identifies specific wavelengths where ground-state and Feshbach molecules are equally trapped, aiding quantum gas experiments.

Findings

Identification of 'magic' wavelengths for Cs₂ molecules.

Polarizability equality between ground-state and Feshbach molecules at these wavelengths.

Enhanced efficiency in transferring molecules to the ground state.

Abstract

The present paper aims at finding optimal parameters for trapping of Cs$_2$ molecules in optical lattices, with the perspective of creating a quantum degenerate gas of ground-state molecules. We have calculated dynamic polarizabilities of Cs$_2$ molecules subject to an oscillating electric field, using accurate potential curves and electronic transition dipole moments. We show that for some particular wavelengths of the optical lattice, called "magic wavelengths", the polarizability of the ground-state molecules is equal to the one of a Feshbach molecule. As the creation of the sample of ground-state molecules relies on an adiabatic population transfer from weakly-bound molecules created on a Feshbach resonance, such a coincidence ensures that both the initial and final states are favorably trapped by the lattice light, allowing optimized transfer in agreement with the experimental observation.