ATOM-INTERFEROMETRIC DETERMINATION OF THE DC-STARK SHIFT OF THE MG-INTERCOMBINATION LINE

The dc-Stark shift of the magnesium 3s2(S-1(0))-3s3p(P-3(1)) line is measured by subjecting both arms of an atom interferometer to a constant electric field. In this interferometer based on Ramsey's method of separated oscillating fields each am is uniquely associated with either the upper or lower state of the intercombination transition, so that the Stark energy perturbation provides two different potentials in the two arms of the interferometer. The resulting relative phase shift corresponds to a difference of - (8.0 +/- 1.0) kHz (kV/cm)-2 in the polarizabilities of the S-1(0) and the P-3(1)(Absolute value of m = 1) states, in agreement with a theoretical calculation.