Cavity attenuated phase shift Faraday rotation spectroscopy

TL;DR

This paper introduces a highly sensitive cavity attenuated phase shift Faraday rotation spectroscopy system for oxygen detection near 762 nm, achieving record sensitivity without high-rate data acquisition.

Contribution

The work demonstrates a novel combination of high-finesse cavity and phase-sensitive polarimetric detection for enhanced sensitivity in Faraday rotation spectroscopy.

Findings

Minimum detectable polarization rotation angle of 5.6e-9 rad/√Hz

Absorption sensitivity of 4.5e-10 cm⁻¹/√Hz

Effective detection of oxygen near 762 nm

Abstract

Cavity attenuated phase shift Faraday rotation spectroscopy has been developed and demonstrated by oxygen detection near 762 nm. The system incorporates a high-finesse cavity together with phase-sensitive balanced polarimetric detection for sensitivity enhancement and achieves a minimum detectable polarization rotation angle (1{\sigma}) of $5.6\times 10^{-9}$ rad/$\surd$Hz, which corresponds to an absorption sensitivity of $4.5\times 10^{-10}$ cm$^{-1}/{\surd}$Hz without the need for high sampling rate data acquisition.