Velocity-tunable magneto-optical-trap-based cold Cs atomic beam

摘要

We report our observation and investigation of a magneto-optical-trap- (MOT)-based low-velocity Cs atomic beam for atomic clock applications. We generated a continuous Cs atomic beam from a vapor-cell MOT of Cs atoms by forming a leak tunnel along one of the trapping laser beams. The mean velocity of the cold Cs beam is measured by the time-of-flight technique to be 7.3 m/s with a velocity spread of 1 m/s under nominal experimental conditions. By adjusting the MOT parameters, we are able to tune the Cs beam velocity from 5 to 8.5 m/s while the velocity spread remains at 1 m/s. The Cs beam has an instantaneous atomic flux of 3.6 x 10(10) atoms/s when operated in pulsed mode and an estimated continuous beam flux of 2 x 10(8) atoms/s. The acceleration kinetics of the Cs beam in the acceleration region is analyzed and simulated. Our theoretical model reveals that the MOT inhomogeneous magnetic field and the varying Doppler shift along the atomic beam propagation play an important role in the determination of the final velocity of the Cs atomic beam. Our numerical results of the atomic beam velocity on MOT parameters agree well with the measurements. (C) 2003 Optical Society of America. [References: 15]