Frequency measurement of the40Ca+clock transition using a LD-based clock laser and UTC(NICT)
K. Matsubara, Y. Li, Shigeo Nagano +6 more
We developed an optical frequency standard with the 4 2S1/2-3 2D5/2 electric quadrupole transition of 40Ca+ ions. Its absolute transition frequency is 411 042 129 776 390(±7) Hz. The accuracy is limited by the electric quadrupole shift and the ambient magnetic field fluctuation. To determine the absolute transition frequency with a better accuracy, we have observed two pairs of the symmetrically-splitting Zeeman components and measured the transition frequency corrected for the electric quadrupole shift. In addition, we are developing a magnetic-shielded ion-trap chamber to suppress the transition-line broadening caused by the magnetic field fluctuation.
Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Aug 20, 2009•0 citations