Isotope shift and hyperfine structure measurements of 4s ~2S _(1/2) → 6s ~2S_(1/2) two-photon transition of potassium isotopes

摘要

Hyperfine splittings for the ~(39)K and ~(41)K isotopes and the isotope shift for the 4s ~2S_(1/2) → 6s ~2S_(1/2) two-photon transition have been measured using sub-Doppler fluorescence spectroscopy. We have accurately measured the transition isotope shift, and a discrepancy has been found in the earlier reported transition isotope shift value, which has been corrected. The resulting hyperfine splitting values of 418.2 (5) and 230.4 (1.3) MHz for the ~(39)K and ~(41)K isotopes respectively are in agreement with previous measurements. The precision of the absolute frequency values for the two-photon transition has been improved by about two orders. Our measured magnetic dipole constants for the upper 6 ~2S_(1/2) state for the ~(39)K and the ~(41)K isotopes are consistent with the earlier measured values.