Infoscience

Journal article

Inner-shell magnetic dipole transition in Tm atoms: A candidate for optical lattice clocks

We consider a narrow magneto-dipole transition in the Tm-169 atom at the wavelength of 1.14 mu m as a candidate for a two-dimensional-optical lattice clock. Calculating dynamic polarizabilities of the two clock levels [Xe]4f(13)6s(2)(J = 7/2) and [Xe]4f(13)6s(2)(J = 5/2) in the spectral range from 250 to 1200 nm, we find a "magic" wavelength for the optical lattice at 807 nm. Frequency shifts due to black-body radiation (BBR), the van der Waals interaction, the magnetic dipole-dipole interaction, and other effects which can perturb the transition frequency are calculated. The transition at 1.14 mu m demonstrates low sensitivity to the BBR shift corresponding to 8 x 10(-17) in fractional units at room temperature which makes it an interesting candidate for high-performance optical clocks. The total estimated frequency uncertainty is less than 5 x 10(-18) in fractional units. By direct excitation of the 1.14 mu m transition in Tm atoms loaded into an optical dipole trap, we set the lower limit for the lifetime of the upper clock level [Xe]4f(13)6s(2) (J = 5/2) of 112 ms which corresponds to a natural spectral linewidth narrower than 1.4 Hz. The polarizability of the Tm ground state was measured by the excitation of parametric resonances in the optical dipole trap at 532 nm.

Fulltext

Related material