Laser frequency offset-locking using electromagnetically induced transparency spectroscopy of <sup>85</sup>Rb in magnetic field

Laser frequency offset-locking using electromagnetically induced transparency spectroscopy of ⁸⁵Rb in magnetic field

Wang Han-Mu^{1, 2}, Cheng Hong^{1, 2}, Zhang Shan-Shan^{1, 2}, Xin Pei-Pei^{1, 2}, Xu Zi-Shan^{1, 2}, Liu Hong-Ping^{1, 2, †}

(color online) (a) Experimental setup for frequency offset-locking using EIT and (b) the related transition energy levels. ISO: optical isolator; λ/2: half-wave plate; PBS: polarization beam splitter; SAS: saturated absorption spectroscopy; PM: permanent magnet; PD: photo detector; LIA: locking-in amplifier. Note that the parts in the dotted frame are not necessary for the offset-locking. They are used to evaluate the stability of the offset-locking. See text for details.