Laser-Cooled Continuous Cs-Beam Master Oscillator; Conference paper

摘要

In this paper we present our design and prospects of a Magneto- Optical Trap (MOT)-based cold Cs-beam atomic clock physics package and report the realization and characterization of a continuous, laser-cooled Cs atomic beam from a Cs MOT. We have determined the longitudinal velocity of the cold Cs beam by Time of Flight (TOF) method to be 7 m/s with a velocity spread of 1 m/s. By adjusting the MOT parameters, we are able to tune the Cs-beam velocity from 5 m/s to 8.5 m/s while the velocity spread remains to be 1 m/s. The Cs beam has an instantaneous atomic flux of 3.6 x 10(exp 10) atoms/s when operated in pulsed mode and a continuous beam flux of 2 x 10(exp 8) atoms/s. Our theoretical simulation reveals that the MOT inhomogeneous magnetic field and the varying Doppler shift along the atomic beam propagation play an important role in determining the longitudinal velocity of the Cs atomic beam. With the cold Cs beam thus formed and a compact Ramsey cavity of 13 cm in length, we have estimated a short-term, shot-noise limited Allan standard deviation of 2.7 x 10(exp -13) tau(exp -1/2) (tau is the averaging time) for the atomic master oscillator under development.