Raman Gray Molasses Cooling of Cesium Atoms on the D2 Line

TL;DR

This paper demonstrates effective Raman gray molasses cooling of cesium atoms on the D2 line, achieving ultra-cold temperatures and significantly increased phase space density, which enhances atomic cooling techniques.

Contribution

The study provides a systematic approach to implement Raman gray molasses cooling on cesium D2 line, achieving lower temperatures and higher phase space density than traditional methods.

Findings

Achieved atom temperature of 1.7 μK after RGMC

Increased phase space density by over 1000 times compared to bare MOT

Demonstrated simplicity of implementation due to hyperfine splitting

Abstract

We present a systematic study on the Raman gray molasses cooling (RGMC) of cesium atoms on the $D_2$ transition. Due to the large splitting in the excited hyperfine transitions of cesium $D_2$ line, it is relatively simple to implement the RGMC with suitable frequency control on the trapping and repumping lasers of the magneto-optical trap (MOT). We have achieved an atom temperature of 1.7$\pm$0.2 $\mu$K after the RGMC with $3.2\times 10^8$ atoms. The phase space density is $1.43\times 10^{-4}$. Compared to the condition with a bare MOT or the MOT with a standard polarization gradient cooling, the phase space density increases by a factor of more than $10^3$ or $10$, respectively.