Precision measurement of the hyperfine structure of the 85Rb 6P3/2 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.