Ichiro Ushijima, Masao Takamoto, Hidetoshi Katori
We experimentally investigate the lattice-induced light shift by the electric-quadrupole (E2) and magnetic-dipole (M1) polarizabilities and the hyperpolarizability in Sr optical lattice clocks. Precise control of the axial as well as the radial motion of atoms in a one-dimensional lattice allows observing the E2-M1 polarizability difference. Measured polarizabilities determine an operational lattice depth to be 72(2)ER, where the total light shift cancels to the 10−19 level, over a lattice-intensity variation of about 30%. This operational trap depth and its allowable intensity range conveniently coincide with experimentally feasible operating conditions for Sr optical lattice clocks.
Physical Review Letters : https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.263202