Precision measurement of the hyperfine structure of the 85 Rb 6P 3/2 state

Partly subjected to the stability of optical frequency source, the magnetic dipole and electric quadrupole hyperfine constants of the 85 Rb 6P 3/2 State have been reported to be 8.163(4) MHz and 8.191(27) MHz, respectively. To pursue the higher precision, here we have constructed two more robust 85 Rb spectrometers with a preliminary stability of 2.3×10 −13 /√τ based on the modulation transfer spectroscopy technique of 85 Rb 5S 1/2 –6P 3/2 transition. By the heterodyne experiment between the two 85 Rb spectrometers, we have measured the hyperfine separations of 85 Rb 6P 3/2 , and obtained the magnetic dipole constant and the electric quadrupole constant which are 8.220 MHz and 5.148 MHz respectively, not considering the systematic errors yet.