Precise determination of the isotope shift of 88Sr-87Sr optical lattice clock by sharing perturbations

Abstract

We report on the isotope shift between 88Sr and 87Sr on the S0-3P0 clock transitions. The interleaved operation of an optical lattice clock with two isotopes allows the canceling out of common perturbations, such as the quadratic Zeeman shift, the clock-light shift, and the blackbody radiation shift. The isotope shift is determined to be 62188 134.004(10) Hz, where the major uncertainty is introduced by the collisional shift that is distinct for each isotope. Our result allows us to determine the frequency of 88Sr-87Sr optical lattice clocks with a fractional uncertainty of 2 × 10-17. The scheme is generally applicable for measuring the isotope shift with significantly reduced uncertainty.