Polarization switching detection method using a ferroelectric liquid crystal for dichroic atomic vapor laser lock frequency stabilization techniques.

We present a concept of the polarization switching detection method implemented for frequency-stabilized lasers, called the polarization switching dichroic atomic vapor laser lock (PSDAVLL) technique. It is a combination of the well-known dichroic atomic vapor laser lock method for laser frequency stabilization with a synchronous detection system based on the surface-stabilized ferroelectric liquid crystal (SSFLC).The SSFLC is a polarization switch and quarter wave-plate component. This technique provides a 9.6 dB better dynamic range ratio (DNR) than the well-known two-photodiode detection configuration known as the balanced polarimeter. This paper describes the proposed method used practically in the VCSEL laser frequency stabilization system. The applied PSDAVLL method has allowed us to obtain a frequency stability of 2.7×10⁻9 and a reproducibility of 1.2×10⁻8, with a DNR of detected signals of around 81 dB. It has been shown that PSDAVLL might be successfully used as a method for spectra-stable laser sources.