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

Abstract

We consider a narrow magneto-dipole transition in the 169 Tm atom at the wavelength of 1.14 µm as a candidate for a 2D optical lattice clock. Calculating dynamic polarizabilities of the two clock levels [Xe]4f13 6s 2 (J = 7/2) and [Xe]4f 13 6s 2 (J = 5/2) in the spectral range from 250 nm to 1200 nm, we suggest the "magic" wavelength for the optical lattice at 807 nm. Frequency shifts due to blackbody 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 µm demonstrates low sensitivity to the BBR shift corresponding to 8 × 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 × 10 −18 in fractional units. By direct excitation of the 1.14 µm 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.

New Methods for Testing Lorentz Invariance with Atomic Systems

“…For the LV tests in the electron sector with neutral atoms, the ground state of Tm, having the the same electronic 4f 13 6s 2 2 F 7/2 configuration as Yb + , appears to be rather well suited as it has the same high sensitivity as Yb + . Moreover, Tm is already being pursued for the lattice clock development, and trapping of the ensemble of Tm atoms in a 1D optical lattice has been demonstrated [20]. We note that a Tm clock is not needed for an LV test, just the ability to perform the scheme described here for the Tm ground state.…”

Subnanometer optical linewidth of thulium atoms in rare-gas crystals

“…We measured the lifetime of the metastable 2 F represent the effects of statistical errors on the fit, assuming uncorrelated noise. Both of these values are much smaller than the lifetime of 75(3) ms measured in solid helium [5] and 112(4) ms in a 1D-optical lattice [30]. We speculate that this might be explained by a non-centrosymmetric trapping site leading to a small electric dipole matrix element.…”

“…The lifetime of the 2 F 5/2 state was found to be about 75 ms in solid helium [5] and 112 ms in an optical lattice [30]. Because of the small sensitivity to blackbody radiation, this transition is suggested as a possible optical clock [30,31].…”

Anisotropic optical trapping as a manifestation of the complex electronic structure of ultracold lanthanide atoms: The example of holmium

“…in Table II. (iii) Polarizabilities are calculated using Eqs. (20) and (21); to that end, the weights w…”