Off-resonance laser frequency stabilization method by Faraday rotation spectroscopy using acoustic-optic modulator

Abstract

We propose a far off-resonance laser frequency stabilization method that can accurately adjust the frequency lock points based on the Faraday rotation spectroscopy. The atomic magnetometer based on the spin-exchange relaxation-free (SERF) theory needs to stabilize the frequency of the probe laser on the detuning of several gigahertz (GHz) away from the resonance of the alkali metal atom, to reduce the absorption of the probe light by the alkali metal vapor cell. We propose a laser frequency stabilization method that can accurately adjust the frequency lock points using an acousto-optic modulator based on Faraday rotation spectroscopy. We reveal the principles of the method and simulate the new Faraday rotation spectra. Besides, we study the effect of the amount of frequency shift of the acousto - optic modulator and the temperature of the alkali metal vapor cell on the frequency lock points of the spectra, and give the formula for calculating the frequency point. Our proposed laser frequency stabilization method can stabilize the laser frequency on the detuning of several gigahertz (GHz) away from the resonance of the alkali metal atom and can adjust the frequency lock points quickly and accurately. This method can be used in atomic magnetometer, degenerate Raman sideband cooling (DRSC) and two photon excitation of Rydberg states.