Investigation of a laser frequency stabilization method based on linear magneto-optics effect

Abstract

Recent progresses in the investigation of nonlinear magneto-optics effects and the field of exploring fundamental physical problems became possible largely due to the development of various frequency stabilized diode laser systems. The typical frequency stabilization method is based on saturated absorption spectrum, which usually just stabilizes the frequency to the center of the resonance line. In this paper, a laser frequency stabilization method is investigated based on linear magneto-optical effect, which can extend the frequency stabilization tuning range to the wings of the resonance line. The optical system is a sequence of a linear polarizer, a cesium atomic vapor cell, a λ/4 plate and a Wollaston prism to separate two polarizing beams. The outgoing lights are detected by two photodiodes with the same type to get the differential signal of intensities. With fixed angle of the λ/4 plate respect to the Wollaston prism, a small rotation of the polarizer will produces a common offset of the differential signal, which will lead to movements of the zero-crossing point along the frequency detuning axis. This behavior can be used to tune the laser frequency on the wings of the resonance line. To analyze the properties and the theoretical value of differential signal of our experimental frequency stabilization system, Jones matrix approach is used. The experimental results show that this method can be used in laser frequency stabilization by extending the frequency tuning range to the wings of a resonance line.