Purely optical macroscopic trap for alkaline-earth and similar atoms

TL;DR

This paper introduces a novel purely optical macroscopic trap for alkaline-earth atoms using bichromatic laser fields, enabling deep trapping and sub-Doppler cooling without magnetic fields, beneficial for quantum sensors and frequency standards.

Contribution

The study demonstrates a new optical trapping method with bichromatic fields that surpasses traditional traps by eliminating magnetic fields and achieving lower temperatures.

Findings

Enables deep macroscopic trapping of alkaline-earth atoms.

Achieves sub-Doppler cooling in a purely optical trap.

Potential applications in quantum sensors and optical standards.

Abstract

We consider a laser cooling and trapping of alkaline-earth and similar atoms in a bichromatic field resonant to a closed optical transition $^1S_0 \to \, ^1P_1$ or $^1S_0 \to \, ^3P_1$. It is shown that new kinetic effects emerge compared to monochromatic fields, enabling the formation of a deep macroscopic trap capable of capturing and cooling neutral atoms to sub-Doppler temperatures. Such a purely optical macroscopic trap can serve as an alternative to the well-known magneto-optical trap and can be used in applications requiring minimization of the magnetic field in the cold atom cloud region. The obtained results are of interest for the new generation of quantum sensors and optical frequency standards.