Abstract
Quartz-enhanced photoacoustic spectroscopy with a near infrared distributed feedback diode laser at 1.53 μm is demonstrated for acetylene detection at atmospheric pressure and room temperature. The P(9) absorption line in the ν 1+ν 3 band of C 2H 2 is selected for light absorption and photoacoustic pressure wave excitation. A pair of resonant tubes with optimal dimensions is used in combination with a quartz tuning fork for photoacoustic signal enhancement. The wavelength of diode laser is modulated at half of the resonant frequency of tuning fork for second harmonic signal detection. The effect of residual amplitude modulation is theoretically analyzed and compared with the experimental results. A noise-limited minimum detectable concentration (1σ) of 2 part-per-million (ppm) is achieved with a 7-mW laser power and a 1-s lock-in time constant, corresponding to a normalized noise equivalent absorption coefficient of 5.4×10 -8 cm -1 W/√Hz.
Original language | English |
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Title of host publication | Optical Sensing and Detection II |
Volume | 8439 |
DOIs | |
Publication status | Published - 12 Jun 2012 |
Event | Optical Sensing and Detection II - Brussels, Belgium Duration: 16 Apr 2012 → 19 Apr 2012 |
Conference
Conference | Optical Sensing and Detection II |
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Country/Territory | Belgium |
City | Brussels |
Period | 16/04/12 → 19/04/12 |
Keywords
- Acetylene detection
- QEPAS
- Quartz tuning fork
- Residual amplitude modulation
- Wavelength modulation
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering