Measurement of Magnetic Field Stability Using 40Ca+ ion

in this paper, we present the preliminary results of a local magnetic field measurement at the position of Ca-40(+) ion. We employ the simultaneous locking of the frequency of clock laser onto two transitions of Zeeman sublevels on transition 4s S-2(1/2) (m=-1/2) - 3d D-2(5/2) (m=-1/2 and -5/2). The frequency deviation from the spectral line center of both selected Zeeman transitions determines the magnetic field value on basis of the linear Zeeman shift thus one can estimate the clock frequency of the unperturbed 4s S-2(1/2) - 3d (2)(D5/2) transition.