Two-photon frequency comb spectroscopy of the 6s-8s transition in cesium.
We report a new absolute frequency measurement of the Cs 6s-8s two-photon transition measured using frequency comb spectroscopy. The fractional frequency uncertainty is 5x10(-11), a factor of 6 better than previous results. The comb is derived from a stabilized picosecond laser and referenced to an octave-spanning femtosecond frequency comb. The relative merits of picosecond-based frequency combs are discussed, and it is shown that the AC Stark shift of the transition is determined by the average rather than the much larger peak intensity.
Fendel
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Max-Planck-Institut für Quantenoptik, Garching, Germany. peter.fendel@mpq.mpg.de
Bergeson
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Udem
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Hänsch
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