Precision measurement of the hyperfine structure of 8d2D3/2 state of 133Cs by the radio-frequency phase modulation technique

We report the measurement of the hyperfine structure in the 8d2D3/2 state of 133Cs isotope by Doppler free two-photon fluorescence spectroscopy in a gas cell. The hyperfine level separations were measured by the radio-frequency phase modulation technique using a frequency stabilized Ti:sapphire laser. The frequency separation between various hyperfine levels of the excited state has been measured with a precision of ~60 kHz. From the measured hyperfine separations of the excited state, we have determined the magnetic dipole coupling constant (A) and the electric quadrupole coupling constant (B) for the 8d2D3/2 state. The determined hyperfine structure constants are A=3.98 (0.01) MHz and B=−0.03 (0.09) MHz. Our deduced magnetic dipole coupling constant (A) value is thus by far the most precise and was found to be in good agreement with the 3σ level with the earlier reported values. This work reports the electric quadrupole coupling constant (B) value for the 8d2D3/2 state for the first time.