Robyr, J.-P. Knowles, Paul E. Weis, Antoine 2010-03-04 The blackbody radiation shift, a manifestation of the Stark effect caused by blackbody radiation, contributes to the systematic uncertainty in Cs-based frequency standards at a level of 1 x 10⁻¹⁵. Few measurements of the third-order scalar electric polarizability of the Cs ground states, mainly responsible for the ac Stark shift in atomic clocks, have given better than 10% accuracy. We report progress in the development of a fully optical Ramsey pump-probe measurement in a thermal atomic beam, based on coherent population trapping (CPT), for the measurement of the third-order scalar and tensor polarizabilities of the Cs ground states. We give details of the apparatus and measurement techniques as well as our first 500 Hz half-period Ramsey fringes application/pdf https://folia.unifr.ch/global/documents/301464 https://folia.unifr.ch/documents/301464/files/weis_ssc.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1109/TUFFC.2010.1455 info:eu-repo/semantics/openAccess License undefined IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. - 2010, vol. 57, no. 3, p. 613 - 617 info:eu-repo/classification/udc/53 Stark shift of the Cs clock transition frequency: a new experimental approach http://purl.org/coar/resource_type/c_6501