Photonic Sensors, Volume. 9, Issue 4, 293(2019)
Trace Ammonia Detection Based on Near-Infrared Fiber-Optic Cantilever-Enhanced Photoacoustic Spectroscopy
A trace ammonia (NH3) detection system based on the near-infrared fiber-optic cantilever-enhanced photoacoustic spectroscopy (CEPAS) is proposed. A fiber-optic extrinsic Fabry-Perot interferometer (EFPI) based cantilever microphone has been designed to detect the photoacoustic pressure signal. The microphone has many advantages, such as small size and high sensitivity. A near-infrared tunable erbium-doped fiber laser (EDFL) amplified by an erbium-doped fiber amplifier (EDFA) is used as a photoacoustic excitation light source. To improve the sensitivity, the photoacoustic signal is enhanced by a photoacoustic cell with a resonant frequency of 1624 Hz. When the wavelength modulation spectroscopy (WMS) technique is applied, the weak photoacoustic signal is detected by the second-harmonic detection technique. Trace NH3 measurement experiments demonstrate that the designed fiber-optic CEPAS system has a linear response to concentrations in the range of 0-20 ppm at the wavelength of 1522.448 nm. Moreover, the detection limit is estimated to be 3.2 ppb for a lock-in integration time of 30 s.
Get Citation
Copy Citation Text
Min GUO, Ke CHEN, Zhenfeng GONG, Qingxu YU. Trace Ammonia Detection Based on Near-Infrared Fiber-Optic Cantilever-Enhanced Photoacoustic Spectroscopy[J]. Photonic Sensors, 2019, 9(4): 293
Category: Regular
Received: Oct. 29, 2018
Accepted: Feb. 19, 2019
Published Online: Dec. 5, 2019
The Author Email: CHEN Ke (chenke@dlut.edu.cn)