Highly Time-Resolved All-Fiber Sensor for Real-Time Carbon Monoxide Detection and Microleakage Diagnosis

The detection of carbon monoxide (CO) is of paramount importance for environmental monitoring, industrial safety, and public health. This study presents an all-fiber gas concentration monitoring technique based on tunable diode laser absorption spectroscopy (TDLAS), offering low gas consumption, high time resolution, high stability, and high precision. A 1-m-long negative curvature anti-resonant hollow core fiber (HCF) with a core diameter of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$110~\mu $ </tex-math></inline-formula>m is used for both gas containment and optical transmission. Experimental and theoretical simulations confirm that the response time of the system reaches 1.27 s at an overpressure of 98 kPa. Furthermore, the system achieves a relative standard deviation (RSD) of less than 2.5% and a minimum detection limit (MDL) of 0.220 ppm under optimal overpressure conditions. In addition, a spatial-resolved scanning imaging is demonstrated for the CO concentration distribution of 190-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>m leakage point, enabling clear identification of the topographical features. This technology has potential in the fields of environmental monitoring, industrial safety, and public health.