Title :
In situ gas-phase ammonia detection using a sensitive photothermal interferometer
Author :
Owens, M.A. ; Davis, C.C. ; Dickerson, R.R.
Author_Institution :
Maryland Univ., College Park, MD, USA
fDate :
31 Oct-3 Nov 1994
Abstract :
Because ammonia sticks to most surfaces and forms particles rapidly, it is difficult to measure. We have shown that photothermal interferometry is an excellent technique for real-time in situ ammonia measurement that is both sensitive and fast. Our photothermal technique uses a modified Jamin interferometer to detect small refractive index changes in air heated by relaxation of vibrationally excited ammonia molecules. Ammonia is excited by infrared light of wavelength 9.22 μm from a grating-tuned CO2 laser
Keywords :
ammonia; 9.22 micron; Jamin interferometer; NH3; gas-phase ammonia detection; grating-tuned CO2 laser; infrared light; photothermal interferometry; real-time in situ measurement; refractive index; relaxation; vibrationally excited molecules; Atmospheric measurements; Calibration; Delay; Detectors; Helium; Laser beams; Laser excitation; Linearity; Optical interferometry; Signal to noise ratio;
Conference_Titel :
Lasers and Electro-Optics Society Annual Meeting, 1994. LEOS '94 Conference Proceedings. IEEE
Conference_Location :
Boston, MA
Print_ISBN :
0-7803-1470-0
DOI :
10.1109/LEOS.1994.586931
