Cavity-enhanced photoacoustic sensor based on a whispering-gallery-mode diode laser

Abstract

Abstract. A cavity-enhanced photoacoustic (CEPA) sensor was developed based on an ultra-narrow linewidth whispering-gallery-mode (WGM) diode laser. A cavity-enhanced photoacoustic module (CEPAM) was designed to match the output beam from the WGM-diode laser, resulting in an increase in the excitation light power, which, in turn, significantly enhanced the photoacoustic signal amplitude. The results show that a signal gain factor of 166 was achieved, which is in excellent agreement with the power enhancement factor of 175 after considering the power transmissivity. The performance of the sensor was evaluated in terms of the detection sensitivity and linearity. A 1σ detection limit of 0.45 ppmV for C2H2 detection was obtained at atmospheric pressure with a 1 s averaging time.

Compact and Highly Sensitive NO2 Photoacoustic Sensor for Environmental Monitoring

“…Optical approaches offer the capability of interference-free direct measurements of NO 2 concentrations without any sample preparation and chemical conversion [1,2,[4][5][6]8]. Photoacoustic spectroscopy (PAS) is one of the most effective optical sensing techniques for trace gas detection due to its advantages of high sensitivity and selectivity as well as compact detection module size [8][9][10][11][12][13][14][15][16][17]. PAS-based sensors have been successfully applied in the field of environmental trace gas monitoring [15][16][17].…”

Design of NO2 photoacoustic sensor with high reflective mirror based on low power blue diode laser*

“…When the photoacoustic spectroscopy is combined with the cavity-enhanced absorption spectroscopy, the power in the cavity will be improved. [24][25][26][27][28][29] However, related research has mainly focused on the infrared band, while research on the ultraviolet band has been quite limited.…”

Quartz Enhanced Photoacoustic Detection Based on an Elliptical Laser Beam

“…Various optical sensing methods for atmospheric monitoring have been reported by numerous researchers [6][7][8][9][10]. Compared with other optical spectroscopic techniques, photoacoustic spectroscopy (PAS) technology is one of the most effective approaches for trace gas sensing, in which a microphone is employed to detect acoustic signals generated by the modulated optical radiation in a weakly absorbing gas [11][12][13]. PAS technology has many advantages, such as wavelength independence and zero-background signal.…”