Precise measurement of hyperfine structure in the ${2P}_{1/2}$ state of $^{7}$Li using saturated-absorption spectroscopy

摘要

We report a precise measurement of the hyperfine interval in the ${2P}_{1/2}$state of $^{7}$Li. The transition from the ground state ($D_1$ line) isaccessed using a diode laser and the technique of saturated-absorptionspectroscopy in hot Li vapor. The interval is measured by locking anacousto-optic modulator to the frequency difference between the two hyperfinepeaks. The measured interval of 92.040(6)~MHz is consistent with an earliermeasurement reported by us using an atomic-beam spectrometer [Das andNatarajan, J.\ Phys.\ B {\bf 41}, 035001 (2008)]. The interval yields themagnetic dipole constant in the $P_{1/2}$ state as $A=46.047(3)$, which isdiscrepant from theoretical calculations by $>80$~kHz.