6 research outputs found
Line shape measurements of rubidium 5S-7S two-photon transition
We report the use of a digital lock to measure the line profile and center frequency of rubidium 5S-7S two-photon transitions with a cw laser referenced to an optical frequency comb. The narrow, two-photon transition, 5S-7S (760 nm), insensitive to first-order in a magnetic field, is a promising candidate for frequency reference
Experimenting an optical second with strontium lattice clocks
Progress in realizing the SI second had multiple technological impacts and
enabled to further constraint theoretical models in fundamental physics.
Caesium microwave fountains, realizing best the second according to its current
definition with a relative uncertainty of 2-4x10^(-16), have already been
superseded by atomic clocks referenced to an optical transition, both more
stable and more accurate. Are we ready for a new definition of the second? Here
we present an important step in this direction: our system of five clocks
connects with an unprecedented consistency the optical and the microwave
worlds. For the first time, two state-of-the-art strontium optical lattice
clocks are proven to agree within their accuracy budget, with a total
uncertainty of 1.6x10^(-16). Their comparison with three independent caesium
fountains shows a degree of reproducibility henceforth solely limited at the
level of 3.1x10^(-16) by the best realizations of the microwave-defined second.Comment: 9 pages, 4 figures, 2 table
Optical Lattice Clocks as Candidates for a Possible Redefinition of the SI Second
International audienc