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Indexed by:Journal Papers

Date of Publication:2020-03-01

Journal:OPTICS AND LASER TECHNOLOGY

Included Journals:EI、SCIE

Volume:123

ISSN No.:0030-3992

Key Words:Trace gas detection; Double resonance; Cantilever; Fiber-optic sensor; Photoacoustic spectroscopy

Abstract:An ultra-high sensitive trace gas detection method based on tube-cantilever double resonance enhanced fiberoptic photoacoustic spectroscopy (PAS) is proposed. The first-order resonant frequencies of the acoustic resonant tube and the fiber-optic cantilever microphone were both equal to the frequency of the photoacoustic pressure signal. This method combines the amplitude amplification of the photoacoustic pressure wave in an acoustic resonant tube with the response enhancement of the photoacoustic signal by the cantilever, making the gas detection extremely sensitive. An experimental double resonance enhanced photoacoustic spectrometer was built for trace acetylene detection at the wavelength of 1532.83 nm. A noise equivalent detection limit (1 sigma) was achieved to be 27 ppt with a 200-s averaging time, which is the best value reported so far. In addition, the normalized noise equivalent absorption (NNEA) coefficient reached 4.2 x 10(-10) cm(-1) W Hz(-1/2).