Antiresonant Hollow Core Fiber-assisted Photothermal Spectroscopy of Nitric Oxide at 5.26 µm

Abstract

Laser-based gas detection techniques are undergoing continuous, rapid development due to the wide area of applications in medicine, environmental monitoring, military applications etc. The development of antiresonant hollow-core fibers (ARHCFs) capable of transmitting with low-loss mid-infrared radiation enabled developing novel, miniaturized and very sensitive gas spectrometers. The unique design of the ARHCFs limits the overlap of the propagating beam with the glass cladding, at the same time ensuring single-transversal-mode operation at the wavelengths suitable for targeting strong transitions of numerous gas molecules. This fact combined with large diameters of the hollow cores (>100 µm) allows for non-complex gas exchange, which ensures low response time of the sensors based on these unique fibers. With proper design, ARHCF-based laser gas detectors can have several-meter-long beam-gas interaction path-lengths, thus reaching minimum detection limits (MDL) matching, or even outperforming sensors based on traditional multipass absorption cells [1] .