Observation of the $^1S_0$\rightarrow$^3P_0$ Clock Transition in $^27\mathrmAl^+$
We report, for the first time, laser spectroscopy of the 1S0â3P0 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 aluminumâs electronic state to the berylliumâs hyperfine state, which can be measured with high fidelity. These techniques are applied to measure the clock transition frequency Î½=1â121â015â393â207â851(6)ââHz. They are also used to measure the lifetime of the metastable clock state Ï=20.6Â±1.4ââs, the ground state 1S0g factor gS=-0.000â792â48(14), and the excited state 3P0g factor gP=-0.001â976â86(21), in units of the Bohr magneton.