Observation of the 1S0-3P0 clock transition in 27Al+
Till P. Rosenband, P. O. Schmidt, David Hume, Wayne M. Itano, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Jeroen Koelemeij, James C. Bergquist, David J. Wineland
We report for the first time, laser spectroscopy of the 1S0 – 3P0 clock transition in 27Al+. A single aluminum ion and a single beryllium ion are simultaneously confined in a linear Paul trap, coupled by their mutual Coulomb repulsion. This coupling allows the beryllium ion to sympathetically cool the aluminum ion, and also enables transfer of the aluminum's electronic state to the beryllium's hyperfine state, which can be measured with high fidelity. These techniques are applied to a measurement of the clock transition frequency, Ņ = 1 121 015 393 207 851(8) Hz. They are also used to measure the lifetime fo the metastable clock state, τ = 20.6+/-1.4 s, the ground state 1S0 g factor, gs = -0.00079248(14), and the excited stated 3P0 g factor = -0.00197686(21) in units of Bohr magneton.