Determination of the magnetic dipole coupling constant of 9S1/2 level in cesium by Doppler-free two-photon spectroscopy

The magnetic dipole coupling constant (A) for the excited 9S1/2 level 133Cs isotope has been measured by Doppler-free two-photon fluorescence spectroscopy. The measured hyperfine splitting value of 4377.1(5) MHz is in agreement with previous measurement. Our measured magnetic dipole constant (A) value of 109.7(5) MHz for the upper 9 2S1/2 state for the 133Cs isotope is in consistent with the only earlier measured value by femtosecond frequency comb technique in a sequential excitation scheme. (author)