Trace gas sensing based on multi-quartz-enhanced photothermal spectroscopy

Abstract

A multi-quartz-enhanced photothermal spectroscopy (M-QEPTS) based trace gas detection method is reported for the first time. Different from traditional QEPTS sensor employing a single quartz tuning fork (QTF) as a photothermal detector, two QTFs were used in M-QEPTS to increase the signal amplitude by adding the generated piezoelectric signals. The coating film of the QTFs was removed in order to improve the laser absorption and transmission. Acetylene (C 2 H 2 ) was chosen as the target analyte. Wavelength modulation spectroscopy (WMS) and 2nd harmonic detection were utilized for the concentration detection. Limit of detection (LoD) of 0.97 ppm was achieved with a 1 second integration time for the M-QEPTS sensor, which realized a 1.51 times signal enhancement compared to a traditional QEPTS sensor employing a single QTF. By using an Allan deviation analysis approach, LoD of 0.19 ppm for an optimum integration time of 200 s was obtained.

Identification of aluminum alloy by laser‐induced breakdown spectroscopy combined with machine algorithm

“…Conventional alloy detection methods include inductively coupled plasma atomic emission spectrometry (ICP‐AES), spark source atomic emission spectrometry (spark‐OES), and X‐ray fluorescence (XRF) 2‐4 . LIBS technology can overcome the limitations of other methods, without the need for cumbersome sample preprocessing, enabling remote, real‐time, and online element detection 5‐10 …”

Ultra-Highly Sensitive Hydrogen Chloride Detection Based on Quartz-Enhanced Photothermal Spectroscopy

“…When the laser arrives at the QTF, the laser energy is absorbed by the QTF and converted into thermal energy [23,24]. Because of thermoelastic expansion, the thermal energy is translated into mechanical motion, which is enhanced by the resonant property of the QTF [25,26]. The mechanical motion creates an electrical signal due to the piezoelectric effect.…”

Performance enhancement of DFBL based near‐infrared CH4 telemetry system using a focus tunable lens

“…Optical gas sensing methods have been widely used in trace gas detection 4,5 . The most widely used optical gas sensing method for detection of atmospheric CH 4 is tunable diode laser absorption spectroscopy (TDLAS) 6,7 .…”

“…Optical gas sensing methods have been widely used in trace gas detection. 4,5 The most widely used optical gas sensing method for detection of atmospheric CH 4 is tunable diode laser absorption spectroscopy (TDLAS). 6,7 TDLAS has the characteristics of noncontact, high sensitivity, strong anti-interference ability, and real-time response.…”