3D optical lattices cooling of ultracold Cs atoms

Abstract

Laser cooling of atoms is the basis of researches on ultracold atoms and molecules. It is of great importance in the study of precision measurement and quantum simulation, etc. In order to obtain ultracold cesium atomic sample with a lower temperature and a higher density, as the starting point to create ultracold cesium ground state molecules, we demonstrate in this article a method which effectively overcomes the heating from the reabsorption of scattered light in magneto-optical trap to further reduce the ultracold atomic temperature by loading atoms into a 3D optical lattices. Based on obtaining the ultracold Cs atoms in a standard magneto-optical trap, we use the compressed magneto-optical trap technology to increase ultracold Cs atomic density. Efficient loading of ultracold Cs atoms is achieved by 3D optical lattices which constructed by four lasers; the temperature of the atoms is measured by time-of-flight method. We observed the cooling result that the temperature drops from ~60.0 μK to ~11.6 μK. We also explore the dependence of the atom numbers in the lattice on the frequency of lattice lasers, and lead to the conclusion that the loading rate of the optical lattices reaches its maximum when the lattices laser’s detuning is –15.5 GHz. In the meantime, this paper investigates the use of optical lattice to suppress the heating of the ultracold atoms due to the radiation photons, in this sense, our research has far-reaching significance. Our scheme is advantageous due to its relaxed starting temperature requirement, meaning that 3D DRSC can be directly accomplished in a standard single cell vapour-loaded MOT without reliance on any additional devices such as a Zeeman slower.