Dark State Magnetometer Based on Enhanced Acousto-Optics Modulator

Abstract

We report on detailed experimental setup and the results of an enhanced acousto-optics modulator (AOM) setup for observation of a dark state magnetometer. A Λ-type dark state based on D1 line of 87Rb:F=2→F′=1 Zeeman sub-levels with neon (Ne) buffer gas was created using a single laser and a scanning acousto-optics modulator. The technical challenges in using this method and how to overcome these difficulties are discussed, and we report on the observation of a dark state resonance with linewidth of 168 Hz and a detectable magnetic field of 9 nT. This method offers many advantages, including the creation of mutually coherent beams outside an external cavity diode laser (ECDL), where the beams are equally affected by external perturbations to the ECDL. Only factors related to the AOM dictates the difference between the two beams.