Carrier-free Raman manipulation of trapped neutral atoms

TL;DR

This paper demonstrates an enhanced Raman control scheme for neutral atoms that suppresses carrier transitions, enabling more efficient cooling and manipulation of atomic motion, applicable even with limited optical access.

Contribution

The authors introduce a novel trapping configuration at a node of a blue detuned standing wave to suppress carrier transitions in Raman processes, improving cooling efficiency.

Findings

Achieved five times lower temperature limit for sideband cooling.

Successfully performed Raman cooling to the two-dimensional vibrational ground state.

Demonstrated coherent manipulation of atomic motion in a cavity-coupled system.

Abstract

We experimentally realize an enhanced Raman control scheme for neutral atoms that features an intrinsic suppression of the two-photon carrier transition, but retains the sidebands which couple to the external degrees of freedom of the trapped atoms. This is achieved by trapping the atom at the node of a blue detuned standing wave dipole trap, that acts as one field for the two-photon Raman coupling. The improved ratio between cooling and heating processes in this configuration enables a five times lower fundamental temperature limit for resolved sideband cooling. We apply this method to perform Raman cooling to the two-dimensional vibrational ground state and to coherently manipulate the atomic motion. The presented scheme requires minimal additional resources and can be applied to experiments with challenging optical access, as we demonstrate by our implementation for atoms strongly coupled to an optical cavity.