A Sensitive Carbon Dioxide Sensor Based on Photoacoustic Spectroscopy with a Fixed Wavelength Quantum Cascade Laser.

Shunda Qiao,Xin Yu,Yinqiu Hu,Yufei Ma,Ying He,Yanchen Qu,Zhonghua Zhang,Frank K Tittel,Yao Wang

doi:10.3390/s19194187

Shunda Qiao, Xin Yu + Show 7 more

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https://doi.org/10.3390/s19194187

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Abstract

A photoacoustic spectroscopy (PAS) based carbon dioxide (CO2) sensor with a fixed wavelength quantum cascade laser (FW-QCL) was demonstrated. The emission wavelength of the FW-QCL at 4.42 μm in the mid-infrared spectral region matched a fundamental CO2 absorption line. Amplitude modulation of the laser intensity was used to match the resonant photoacoustic (PA) cell. The noise from the background was reduced with the correlation demodulation technique. The experimental results showed that the sensor had excellent signal stability and a concentration linear response. When the integration time was 1 s, a 1σ minimum detection limit (MDL) of 2.84 parts per million (ppm) for CO2 detection was achieved. The long-term stability of the sensor was evaluated by means of an Allan deviation analysis. With an integration time of ~100 s, the MDL was improved to 1 ppm. This sensor was also used to measure the CO2 concentration from some common emission sources, such as cigarette smoking, automobile exhaust, and the combustion of some carbon-containing materials, which confirmed the stability and robustness of the reported FW-QCL based CO2-PAS sensor system.

Highlights

Carbon dioxide (CO2 ) is a colorless and odorless gas and is one of the main greenhouse gases.With the increasing use of fossil fuel combustion and emissions from automobile exhaust, the CO2 concentration in the atmosphere has increased from 280 parts per million by volume to~400 ppmv since the industrial revolution [1,2]
In order to test the stability of the sensor system, the photoacoustic spectroscopy (PAS) signal was detected with and without fixed wavelength quantum cascade laser (FW-quantum cascade laser (QCL)) many times
A PAS based CO2 sensor using a fixed wavelength (FW)-QCL was demonstrated in this manuscript

Summary

Introduction

Carbon dioxide (CO2 ) is a colorless and odorless gas and is one of the main greenhouse gases.With the increasing use of fossil fuel combustion and emissions from automobile exhaust, the CO2 concentration in the atmosphere has increased from 280 parts per million by volume (ppmv) to~400 ppmv since the industrial revolution [1,2]. Carbon dioxide (CO2 ) is a colorless and odorless gas and is one of the main greenhouse gases. With the increasing use of fossil fuel combustion and emissions from automobile exhaust, the CO2 concentration in the atmosphere has increased from 280 parts per million by volume (ppmv) to. The greenhouse effect has led to global warming, glacier melting, and a rise in sea levels [3,4]. If the CO2 concentration increases even further, these phenomena will become worse and affect people’s life severely in the future. The high concentration of CO2 reduces the pondus hydrogenii (PH) of oceans and soil which impacts marine organisms and plants [5,6]. There is a need to develop a sensitive CO2 gas sensor to monitor CO2 concentrations

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