Title :
An Intensity-Stabilized Diode-Laser Spectrometer for Sensitive Detection of NH3
Author :
Tommasi, Edoardo De ; Casa, Giovanni ; Gianfrani, Livio
Author_Institution :
Dipt. di Sci. Ambientali, Seconda Univ. di Napoli, Caserta
fDate :
4/1/2007 12:00:00 AM
Abstract :
This paper reports on a compact analyzer for ammonia monitoring in the air based on near-infrared wavelength-modulation diode-laser absorption spectroscopy. Particular attention is devoted to the problem of residual amplitude modulation (RAM), which is responsible for the occurrence of the line profiles´ distortions. The RAM effects are eliminated by means of an intensity-control feedback loop based on an acoustooptic modulator. This offers the advantage of simplifying enormously the spectral-analysis procedure, which, otherwise, would require a considerable amount of calculation if the RAM distortions were considered
Keywords :
acousto-optical modulation; ammonia; amplitude modulation; chemical variables measurement; infrared spectrometers; semiconductor lasers; spectrochemical analysis; acousto-optic modulator; ammonia monitoring; diode-laser absorption spectroscopy; diode-laser spectrometer; gas detectors; intensity-control feedback loop; laser measurements; near-infrared wavelength-modulation; residual amplitude modulation; semiconductor lasers; spectral-analysis; Absorption; Diode lasers; Laser feedback; Laser modes; Laser noise; Laser theory; Passive optical networks; Semiconductor diodes; Semiconductor lasers; Spectroscopy; Gas detectors; laser measurements; semiconductor lasers; spectral analysis; spectroscopy;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
DOI :
10.1109/TIM.2007.891161
