Ultra-sensitive single-beam atom-optical magnetometer using weak measurement method

Abstract

Ultra-sensitive measurement of the magneto-optical rotation, due to interaction of linearly-polarized light passing through room-temperature Rb 85 atoms, in response to change in longitudinal magnetic field (δ B z ) is demonstrated using the weak measurement method. The polarization rotation angle measurement sensitivity (δ φ ) of 16 µrad and hence of the magnetometer of 1 nT, achieved using the weak measurement method is better than the balanced optical polarimetry results by a factor of three. The improvement in the measurement sensitivity is realized via optical amplification of the polarization rotation angle via spin-orbit coupled light beam-field. The method is devoid of external rf modulation, allows for optimal tunability of sensitivity depending on the dynamic range of the applied magnetic field and the sensitivity can be further enhanced by operating in the Spin Exchange Relaxation Free regime of alkali spin polarization.

Transition cancellations of $^{87}$Rb and $^{85}$Rb atoms in a magnetic field setting new standards

“…Interest in such single-electron atomic media is caused by the simplicity of energy levels and the presence of strong optical transitions in the visible and near infrared, for which narrow-linewidth cw lasers are widely available. In recent decades, various magneto-optical processes in vapors of alkali metals have been intensively investigated, which is in particular due to interest in the development of new schemes of optical magnetometry [4,5,6]. Among these processes is modification of the frequency and intensity of optical transitions between individual magnetic sublevels of the hyperfine structure of atoms in a magnetic field.…”