Motional-ground-state cooling outside the Lamb-Dicke regime

Abstract

We report Raman sideband cooling of a single sodium atom to its three-dimensional motional ground state in an optical tweezer. Despite a large Lamb-Dicke parameter, high initial temperature, and large differential light shifts between the excited state and the ground state, we achieve a ground state population of 93.5(7)% after 53 ms of cooling. Our technique includes addressing high-order sidebands, where several motional quanta are removed by a single laser pulse, and fast modulation of the optical tweezer intensity. We demonstrate that Raman sideband cooling to the 3D motional ground state is possible, even without tight confinement and low initial temperature.

Dipolar exchange quantum logic gate with polar molecules

“…If the molecules are near the motional ground state with excitations dominated by imperfect cooling of Na, 50 the mean excitation numbers of each molecule along x , y , and z are 0.019, 0.024, and 0.024 respectively. Then motional effects cause a fidelity loss of 9 × 10 –6 for the above trap strength.…”

Forming a Single Molecule by Magnetoassociation in an Optical Tweezer

“…The atoms are then simultaneously cooled to their respective 3D motional ground states by polarization gradient cooling and Raman sideband cooling. Details of the trapping and cooling procedures have been reported previously [21,34]. After the atoms are cooled to their motional ground states, we prepare them in the lowest Zeeman energy level: Na jF ¼ 1; m F ¼ 1i and Cs jF ¼ 3; m F ¼ 3i.…”

Raman sideband cooling in optical tweezer arrays for Rydberg dressing

“…For each cycle we cool the radial axes for 2 ms with ten chirps of 200 µs over 120 kHz to cover the inhomogeneities between the different traps. Then we apply three sub-cycles of axial cooling, each cooling for 200 µs on the 4 th to 1 st axial sideband [55]. The whole cooling takes 150 ms, including switching times.…”

“…Raman sideband cooling provides a very efficent way to optically cool the atoms to the motional ground state in tight traps [49][50][51]. It has been successfully applied to single or few tweezers [52][53][54][55]. Here we demonstrate Raman sideband cooling and single atom trapping in a tweezer array for 39 K atoms.…”