Spectrally selective optical pumping in Doppler-broadened cesium atoms

The D₁ line spectrally selective pumping process in Doppler-broadened cesium is analyzed by solving the optical Bloch equations. The process, described by a three-level model with the L scheme, shows that the saturation intensity of broadened atoms is three orders of magnitude larger than that of resting atoms. The |F_g =3>→|F_e =4> resonance pumping can result in the ground state |F_g =4, m_F =4i sublevel having a maximum population of 0.157 and the population difference would be about 0.01 in two adjacent magnetic sublevels of the hyperfine (HF) state F_g =4. To enhance the anisotropy in the ground state, we suggest employing dichromatic optical HF pumping by adding a laser to excite D₁ line |F_g =4>→jF_e =3> transition, in which the cesium magnetometer sensitivity increases by half a magnitude and is unaffected by the nonlinear Zeeman effect even in Earth’s average magnetic field.