Postselected amplification applied to atomic magnetometers

Abstract We propose to embed the atomic magnetometer (AM) into an optical Mach–Zehnder interferometer (MZI). We analyze the effect of amplification of the Faraday rotation (FR) angle of the probe laser light, by properly postselecting the path-information state of the laser photons when passing through the MZI. In the presence of practical limitations, such as the polarization cross talk in the polarizing-beam-splitter, the amplified FR angle in the postselected photons can make the postselection scheme outperform the conventional measurement, thus further enhancing the sensitivity of the nowadays state-of-the-art optical AM.