High-Sensitivity Silicon Cantilever-Enhanced Photoacoustic Spectroscopy Analyzer with Low Gas Consumption

Abstract

A silicon cantilever-enhanced photoacoustic spectroscopy (PAS)based trace gas analyzer with low gas consumption is presented. A silicon cantilever-based fiber-optic Fabry−Perot (F−P) interferometric acoustic sensor with a compact structure and high sensitivity is designed for photoacoustic signal detection. The non-resonant photoacoustic cell (PAC) is a cylindrical copper tube with a volume of 0.56 mL. A near-infrared laser with a center wavelength of 1532.83 nm amplified using an erbium-doped fiber application amplifier is used as the excitation light. The wavelength modulation spectroscopy (WMS) technique is employed in the present work for second-harmonic photoacoustic signal detection. The experimental results show that the minimum detection limit of C 2 H 2 is 199.8 parts per trillion (ppt) with an average time of 60 s. The normalized noise equivalent absorption coefficient is calculated as 1.72 × 10 −9 cm −1 W/Hz 1/2 . Furthermore, the proposed silicon cantilever-enhanced non-resonant PAS-based gas analyzer can not only analyze the gas concentration in a closed small-capacity PAC with low gas consumption but also detect target gas leakage in real time at a long distance.

High-sensitivity miniature dual-resonance photoacoustic sensor based on silicon cantilever beam for trace gas sensing

“…An Allan-Werle analysis [54] , [55] , [56] , [57] has been realized by filling the designed sensor with pure N 2 and continuously measuring the PA signals for a long time. The Allan-Werle deviation calculated under the pure N 2 background is gained and presented in Fig.…”

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

“…When the integration time (IT) of the three VLIAs is 1 s, the deviations are 1.28, 1.52, and 1.19 pm for CH 4 , C 2 H 2 , and H 2 S, respectively, and based on the detection sensitivities of the gas sensor to CH 4 , C 2 H 2 , and H 2 S, the MDLs for CH 4 , C 2 H 2 , and H 2 S are estimated to be 167, 47.5, and 1597 ppb, respectively. The results of the Allan-Werle analysis − are shown in Figure a–c. When the three ITs are, respectively, 100 s, the corresponding MDLs are 16.6, 4.8, and 162 ppb for CH 4 , C 2 H 2 , and H 2 S. Table summarizes the performance parameters of previously developed sensors based on PAS for single trace gas (CH 4 , C 2 H 2 , and H 2 S) and multiple trace gas (CH 4 and C 2 H 2 ) detection as a comparison to demonstrate the performance of the designed all-optical miniaturized PA sensor.…”

Cantilever-enhanced photoacoustic spectroscopy for gas sensing: A comparison of different displacement detection methods

“…Michelson interferometer has high sensitivity and good stability, but the bulky volume and high cost limit its application in some specific fields. CEPAS based on Fabry-Perot interferometer is relatively compact [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] , [60] , [61] , [62] . A Fabry-Perot cavity is formed between the end facet of the fiber and the free end of the cantilever.…”