Title :
Laser hygrometer using a vertical-cavity surface-emitting laser (VCSEL) with an emission wavelength of 1.84 μm
Author :
Lauer, Christian ; Szalay, Stefan ; Böhm, Gerhard ; Lin, Chun ; Köhler, Fabian ; Amann, Markus-Christian
Author_Institution :
Walter Schottky Inst., Tech. Univ. Munchen, Garching, Germany
fDate :
6/1/2005 12:00:00 AM
Abstract :
This paper presents a hygrometer setup for measuring the concentration of water vapor in air by means of infrared absorption spectroscopy. Recently developed vertical-cavity surface-emitting lasers (VCSELs) emitting near 1.84 μm are used as source of the infrared light. The laser hygrometer is able to calculate the density of water molecules from the measurement of one single light-current characteristic, without any additional reference measurement. The absolute and relative humidity are calculated from the water molecule density and the temperature of the ambient air.
Keywords :
density measurement; humidity measurement; hygrometers; infrared spectroscopy; surface emitting lasers; absolute humidity; ambient air temperature; emission wavelength; infrared absorption spectroscopy; laser hygrometer; relative humidity; vertical-cavity surface-emitting laser; water molecule density; water vapor concentration measurement; Density measurement; Electromagnetic wave absorption; Humidity; Infrared spectra; Spectroscopy; Surface emitting lasers; Surface waves; Vertical cavity surface emitting lasers; Water; Wavelength measurement; Absorption spectroscopy; laser hygrometer; long-wavelength vertical-cavity surface-emitting lasers (VCSELs); trace gas sensing;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
DOI :
10.1109/TIM.2005.847195
