Hyperpolarizability effects in a Sr optical lattice clock.
We report the observation of a higher-order frequency shift due to the trapping field in a (87)Sr optical lattice clock. We show that, at the magic wavelength of the lattice, where the first-order term cancels, the higher-order shift will not constitute a limitation to the fractional accuracy of the clock at a level of 10(-18). This result is achieved by operating the clock at very high trapping intensity up to 400 kW/cm(2) and by a specific study of the effect of the two two-photon transitions near the magic wavelength.
Brusch
Anders
A
LNE-SYRTE, Observatoire de Paris, 61, Avenue de l'Observatoire, 75014 Paris, France.
Le Targat
Rodolphe
R
Baillard
Xavier
X
Fouché
Mathilde
M
Lemonde
Pierre
P