A novel laser intensity stabilization and modulation method based on utilization of Zeeman-Faraday effect in atomic vapor cells.

Utilizing the Zeeman Faraday effect in atomic vapor cells, a novel setup is introduced both for laser intensity stabilization and laser intensity modulation. The method is based on the closed loop control of the polarization rotation angle of the laser light in an atomic vapor cell for adjustment of the laser intensity. Characterizing the implemented setup, it is shown that more than 30 dB attenuation of the optical fluctuation is achieved in the frequency range from DC to 1 kHz. Meanwhile, the laser intensity could be efficiently locked to a modulating voltage signal, which results in amplitude modulation of the laser beam. We believe that this simple method could be effectively used in different atomic physics experiments, including the stabilization of the laser intensity in applications where near resonance frequency sweeping is required or applications that contain optical modulation of lasers in lock-in detection schemes.