Fiber-amplifier-enhanced photoacoustic spectroscopy with near-infrared tunable diode lasers
- 20 April 2003
- journal article
- Published by Optica Publishing Group in Applied Optics
- Vol. 42 (12), 2119-2126
- https://doi.org/10.1364/ao.42.002119
Abstract
A new approach to wavelength-modulation photoacoustic spectroscopy is reported, which incorporates diode lasers in the near infrared and optical fiber amplifiers to enhance sensitivity. We demonstrate the technique with ammonia detection, yielding a sensitivity limit less than 6 parts in 109, by interrogating a transition near 1532 nm with 500 mW of output power from the fiber amplifier, an optical pathlength of 18.4 cm, and an integration time constant of 10 s. This sensitivity is 15 times better than in prior published results for detecting ammonia with near-infrared diode lasers. The normalized minimum detectable fractional optical density, αmin l, is 1.8 × 10-8; the minimum detectable absorption coefficient, αmin, is 9.5 × 10-10 cm-1; and the minimum detectable absorption coefficient normalized by power and bandwidth is 1.5 × 10-9 W cm-1/√Hz. These measurements represent what we believe to be the first use of fiber amplifiers to enhance photoacoustic spectroscopy, and this technique is applicable to all other species that fall within the gain curves of optical fiber amplifiers.Keywords
This publication has 26 references indexed in Scilit:
- Resonant photoacoustic simultaneous detection of methane and ethylene by means. of a 1.63-μm diode laserApplied Physics B Laser and Optics, 2002
- Photoacoustic spectroscopy with quantum cascade distributed-feedback lasersOptics Letters, 2001
- Correlation of breath ammonia with blood urea nitrogen and creatinine during hemodialysisProceedings of the National Academy of Sciences of the United States of America, 2001
- A high-sensitivity, near-infrared tunable-diode-laser-based photoacoustic water-vapour-detection system for automated operationMeasurement Science and Technology, 1999
- Photoacoustic spectroscopy using quantum-cascade lasersOptics Letters, 1999
- Ultrasensitive laser measurements without tearsApplied Optics, 1997
- Photoacoustic spectroscopy on trace gases with continuously tunable CO_2 laserApplied Optics, 1996
- Optoacoustic detection with near-infrared diode lasers: trace gases and short-lived moleculesInfrared Physics & Technology, 1996
- Optoacoustic trace-gas monitoring with near-infrared diode lasersApplied Optics, 1994
- Frequency-modulation spectroscopy for trace species detection: theory and comparison among experimental methodsApplied Optics, 1992