Experimental Determination of the Landé g-Factors for 5s^2^1\!S and 5s5p^3\!P States of the ^87Sr Atom

We present an experimental determination on the Landé g-factors for the 5s^2 ^1\!S_0 and 5s5p ^3\!P_0 states in ultra-cold atomic systems, which is important for evaluating the Zeeman shift of the clock transition in the ^87Sr optical lattice clock. The Zeeman shift of the 5s5p ^3\!P_0–5s^2 ^1\!S_0 forbidden transition is measured with the \pi-polarized and \sigma^\pm-polarized interrogations at different magnetic field strengths. Moreover, in the g-factor measurement with the \sigma^\pm-transition spectra, it is unnecessary to calibrate the external magnetic field. By this means, the ground state 5s^2 ^1\!S_0 g-factor for the ^87Sr atom is -1.306(52)\times10^-4, which is the first experimental determination to the best of our knowledge, and the result matches very well with the theoretical estimation. The differential g-factor \delta g between the 5s5p ^3\!P_0 state and the 5s^2 ^1\!S_0 state of the ^87Sr atoms is measured in the experiment as well, which are -7.67(36)\times10^-5 with \pi-transition spectra and -7.72(43)\times10^-5 with \sigma^\pm-transition spectra, in good agreement with the previous report Phys. Rev. A 76 (2007) 022510. This work can also be used for determining the differential g-factor of the clock states for the optical clocks based on other atoms.