Photothermal gas sensing with a custom-made, fiber-coupled Fabry–Pérot etalon

Abstract

Growing awareness of the adverse health effects of air pollution has increased the demand for reliable, sensitive, and mass-producible sensor systems. Photothermal interferometry has shown great promise for sensitive, selective, and miniaturized gas sensing solutions. This work describes the development of a macroscopic photothermal sensor system with a sensor head consisting of a low-cost, custom-made, and fiber-coupled Fabry-Perot etalon. The sensor was tested with NO2, achieving a 3 sigma limit of detection (LOD) of approximately 370 ppbv (1 s). Exhibiting little drift, a LOD of 15 ppbv is achievable for 200 s integration time. Compensating for the excitation power, the normalized noise equivalent absorption was calculated to be 1.4x10(-8)cm(-1)W root Hz. The sensor system is not limited to NO2 but can be used for any gas or aerosol species by exchanging the excitation laser source. (c) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.