Determination of the hyperfine coupling constants of the 5D5/2 state of 85Rb atoms by using high signal-to-noise ratio electromagnetically-induced transparency spectra

We report the hyperfine splitting measurement of the 85Rb 5D5/2 state by electromagnetically induced transparency spectroscopy with high signal-to-noise ratio in the 85Rb 5S1/2-5P3/2-5D5/2 ladder-type system (m 780 nm + 776 nm). The frequency calibration is performed by employing a phase-type electro-optic modulator with a confocal Fabry-Perot cavity. From the measured hyperfine splittings among the manifolds of (F=5), (F=4) and (F=3) of the 85Rb 5D5/2 state, we determine the magnetic dipole hyperfine coupling constant (A= (-2.222 0.019) MHz) and the quadrupole coupling constant (B= (2.664 0.130) MHz) of 5D5/2 state of 85Rb atoms.