Oxygen Gas Sensing with Photothermal Spectroscopy in a Hollow-Core Negative Curvature Fiber

Abstract

We demonstrate a compact all-fiber oxygen sensor using photothermal interferometry with a short length (4.3 cm) of hollow-core negative curvature fibers. The hollow-core fiber has double transmission windows covering both visible and near-infrared wavelength regions. Absorption of a pump laser beam at 760 nm produces photothermal phase modulation and a probe Fabry-Perot interferometer operating at 1550 nm is used to detect the phase modulation. With wavelength modulation and first harmonic detection, a limit of detection down to 54 parts per million (ppm) with a 600-s averaging time is achieved, corresponding to a normalized equivalent absorption of 7.7 × 10−8 cm−1. The oxygen sensor has great potential for in situ detection applications.

Recent Advances in Spectroscopic Gas Sensing With Micro/Nano-Structured Optical Fibers

“…With the FPI probe configuration operating at 1 550 nm and different pump lasers from 760 nm to 3.5 , detection of oxygen, acetylene, methane, ethane, carbon monoxide, and carbon dioxide down to ppm to ppb level have been demonstrated [50][51][52], showing the potential wide range of applications of the technique.…”

Printable and flexible wireless oxygen sensor

“…The probe end is exposed to the gas species and its relative gas concentration is measured. This reported sensor is compact and has detection levels of 54 ppm [4]. A similar study was discussed based on molecular absorption spectrometry, here light illumination, and gate biasing was used to enhance the oxygen sensing properties by increasing the photogenerated carrier and doping level of the rhenium disulfide (ReS 2 ) field-effect transistor(FET), where ReS 2 FET is used as a sensing element.…”

Gas Sensing System Based on an All-Fiber Photothermal Microcell

“…Various designs of all-fiber photothermal gas sensors were proposed to mitigate these limitations [15]. These designs were based mainly on hollow core/photonic crystal fibers (HC/PCF) [10,[15][16][17][18][19][20], which allow for easy alignment and guidance of the excitation and probe beam over longer distances, thus decreasing the detection limits (down to the ppb range). At the same time, high excitation frequencies can be applied (10 kHz [10], 50 kHz [15], 2.7 kHz [16], 12.5 kHz [17], etc.).…”