MOT-based continuous cold Cs-beam atomic clock

In this paper we report our design and experimental results towards demonstration of a magneto optical trap (MOT)-based cold Cs-beam atomic clock. We generated a continuous cold Cs beam from a Cs MOT by perturbing the MOT potential and measured the longitudinal velocity of the Cs beam to be 7 m/s. In order to separate the atomic beam from the MOT laser beam, we used a one-dimensional optical molasses to deflect the Cs beam through an angle of 30° before the atomic beam enters the microwave cavity. Our Cs beam has an instantaneous atomic flux of 3.6 × 10¹⁰ atoms/s when operated in pulsed mode and a continuous flux of 2 × 10⁸ atoms/s. Under current experimental conditions, the observed cold Cs atomic beam parameters infer a short-term, shot-noise limited Allan standard deviation of 2.7 × 10^-13 τ^-1/2 (τ is the averaging time) for the cold Cs beam clock under development.