Direct Excitation of the Forbidden Clock Transition in Neutral 174Yb Atoms Confined to an Optical Lattice

We report direct single-laser excitation of the strictly forbidden (6s2)1S0↔(6s6p)3P0 clock transition in 174Yb atoms confined to a 1D optical lattice. A small (∼1.2 mT) static magnetic field was used to induce a nonzero electric dipole transition probability between the clock states at 578.42 nm. Narrow resonance linewidths of 20 Hz (FWHM) with high contrast were observed, demonstrating a resonance quality factor of 2.6x1013. The previously unknown ac Stark shift-canceling (magic) wavelength was determined to be 759.35±0.02 nm. This method for using the metrologically superior even isotope can be easily implemented in current Yb and Sr lattice clocks and can create new clock possibilities in other alkaline-earth-like atoms such as Mg and Ca