Abstract

The development of optical frequency standards utilizing neutral atoms is motivated by the superior stability and accuracy that can be achieved as result of a high transition frequency and low sensitivities to external fields. With thermal atoms the accuracy of the spectroscopic signal is limited by the Doppler effect, so that spectroscopy on laser cooled atoms can decrease most uncertainties by orders of magnitude. Furthermore, only cold ensembles allow sufficiently long interaction times to achieve resolutions in the Hz regime.

© 1994 IEEE