High-Sensitivity Multitrace Gas Simultaneous Detection Based on an All-Optical Miniaturized Photoacoustic Sensor

Abstract

We propose an all-optical miniaturized multigas simultaneous detection photoacoustic (PA) sensor, which is primarily composed of a copper tube, a silica cantilever, and four single-mode fibers. Three single-mode fibers are used as excitation fibers to transmit lasers of different wavelengths, and the remaining one is used as a probe fiber. The volumes of the PA cell (PAC) and the sensor are 36 μL and 71 cubic millimeters, respectively. A laser photoacoustic spectroscopy (PAS) system, using the all-optical miniaturized PA sensor as a detector, 1532.8, 1576.3, and 1653.7 nm distributed feedback (DFB) lasers as the excitation sources for acetylene (C2H2), hydrogen sulfide (H2S), and methane (CH4) gases, and a high-speed spectrometer as a demodulator, has been developed for multigas simultaneous measurements. The minimum detection limits of 4.8, 162, and 16.6 parts per billion (ppb) have been achieved for C2H2, H2S, and CH4, respectively, with an integration time of 100 s. The reported sensor shows a potential for high-sensitivity multigas simultaneous measurements in cubic millimeter-scale space.

Multi-pass Differential Photoacoustic Sensor for Real-Time Measurement of SF6Decomposition Component H2S at the ppb Level

“…The PA signal is proportional to the absorption coefficient of the target gas; the selection of the absorption line plays an important role in improving the MDL of the PAS detection system . High absorption coefficient, low interference from other gases, and low cost of light source are momentous indexes for choosing the H 2 S absorption line.…”

“…The PA signal is proportional to the absorption coefficient of the target gas; the selection of the absorption line plays an important role in improving the MDL of the PAS detection system. 31 High absorption coefficient, low interference from other gases, and low cost of light source are momentous indexes for choosing the H 2 S absorption line. PD and POF in GIE result in the decomposition of SF 6 to produce a variety of characteristic components, including SOF 2 , SOF 4 , SO 2 F 2 , SO 2 , CF 4 , CO, CO 2 , HF, and H 2 S. Therefore, the cross interference of the SF 6 background gas and other decomposition products on the characteristic absorption line of H 2 S should be considered.…”

A dual‐resonance enhanced photoacoustic spectroscopy gas sensor based on a fiber optic cantilever beam microphone and a spherical photoacoustic cell

“…[18][19][20][21][22][23] Therefore, researchers have used different ways to optimize the performance of PACs and acoustic sensors to amplify the photoacoustic signals and thus obtain higher sensitivity. [24][25][26][27] In recent years, various shapes of PACs have been proposed and successfully implemented in trace gas sensing. [28][29][30][31][32][33][34] The formation of dual resonance between PAC and acoustic detector can further improve the gas detection limit.…”

“…The photoacoustic effect can be summarized as gas molecules located within a photoacoustic cell (PAC) absorbing light of periodic characteristic wavelengths and then emitting heat, causing the air around the gas molecules to periodically expand to produce sound waves 18–23 . Therefore, researchers have used different ways to optimize the performance of PACs and acoustic sensors to amplify the photoacoustic signals and thus obtain higher sensitivity 24–27 …”

Methane and ethane detection from natural gas level down to trace concentrations using a compact mid-IR LITES sensor based on univariate calibration

“…Several gas sensors for hydrocarbons detection were developed employing optical-based detection techniques. These sensors were mainly operate for methane and ethane detection in trace concentrations for environmental monitoring purposes, exploiting spectroscopic methods as cavity-based techniques [13] , [14] , non-dispersive infrared sensors [15] , [16] , photoacoustic spectroscopy [17] , [18] , [19] , photothermal spectroscopy [20] , [21] , and tunable diode laser absorption spectroscopy (TDLAS) [22] , [23] . These optical sensors exploit the absorption features located in the near- and mid-IR and corresponding to the C-H bond stretching, which characterize the absorption spectra of several alkanes and hydrocarbons (fundamental mode lies in λ = 3–4 µm, first overtone in λ = 1–2 µm).…”