Ammonia, carbon dioxide and water vapor detection based on tunable fiber laser photoacoustic spectroscopy

Tunable laser photoacoustic spectroscopy is attracted as a powerful tool for trace gas detection in environmental applications. A photoacoustic gas sensor using a near-infrared tunable fiber laser and based on wavelength modulation spectroscopy is developed. Continuous measurements of ammonia, carbon dioxide and water vapor in gas mixtures are achieved at atmospheric pressure. The minimum detection limits (signal-to-noise ratio = 1) of 6 ppb of ammonia, 5 ppm of carbon dioxide and 29 ppm of water vapor have been demonstrated with the sensor. Ammonia, carbon dioxide and water vapor in ambient air are measured by the sensor.