Sub-Doppler magneto-optical trap temperatures measured using Rydberg tagging

Abstract

We present measurements of polarization-gradient cooling in a Cs magneto-optic trap (MOT). The temperature in the MOT is found to vary linearly with the light shift. The slope gives a value of $C_{\sigma }=0.25\pm 0.05$ while the minimum temperature $T_0=3.8\pm 3.3\mu \mathrm{K}$, in agreement with measurements done in the absence of a magnetic field. The temperature is determined by using a nondestructive method which uses Rydberg time-of-flight velocity distributions of trapped atoms.