A continuous cold atomic beam from a magneto-optical trap

L. Cacciapuoti, A. Castrillo, Marella de Angelis +1 more

S. Weyers, Eve Aucouturier, Constance Valentin +1 more

Eve Aucouturier

A continuous beam of cold atoms is considered as an alternative to improve the performance of caesium frequency standards. A two-dimensional magneto-optical trap (2D MOT) is outlined. The assembling of three counter-propagating circularly polarised laser beams and of two magnetic field gradients along the horizontal axes leads to a transverse cooling and trapping, whereas in the vertical z-direction the atoms are only cooled and not trapped because of the zero magnetic field in this direction. In order to predict the characteristics of the beam of cold atoms, a simulation of the atomic trajectories was carried out by using a two-dimensional model of Doppler cooling and magneto-optical trapping. The velocity distribution of the atoms, which, due to the trapping and cooling process, enter the zone, where they are launched, is calculated.

Sung Jong Park, Jiho Noh, Jongchul Mun

闫树斌 Yan Shubin, Tao Geng, Tiancai Zhang +1 more

We have established a caesium double magneto-optical trap (MOT) system for cavity-QED experiment, and demonstrated the continuous transfer of cold caesium atoms from the vapour-cell MOT with a pressure of ~ 1 × 10 −6 Pa to the ultra-high-vacuum (UHV) MOT with a pressure of ~ 8 × 10 −8 Pa via a focused continuous-wave transfer laser beam. The effect of frequency detuning as well as the intensity of the transfer beam is systematically investigated, which makes the transverse cooling adequate before the atoms leak out of the vapour-cell MOT to reduce divergence of the cold atomic beam. The typical cold atomic flux got from vapour-cell MOT is ~ 2 × 10 7 atoms/s. About 5 × 10 6 caesium atoms are recaptured in the UHV MOT.

R. Ohmukai, S. Urabe, Makoto Watanabe