Laser hygrometer using a vertical-cavity surface-emitting laser (VCSEL) with an emission wavelength of 1.84 /spl mu/m

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 /spl mu/m 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.

[1]  F. Lobkowicz,et al.  Physics for Scientists and Engineers, Vol. I , 1976 .

[2]  Peter Werle,et al.  A review of recent advances in semiconductor laser based gas monitors , 1998 .

[3]  Markus Ortsiefer,et al.  1.8??m vertical-cavity surface-emitting laser absorption measurements of HCl, H2O and CH4 , 2003 .

[4]  Laurence S. Rothman,et al.  Reprint of: The HITRAN molecular spectroscopic database and HAWKS (HITRAN Atmospheric Workstation): 1996 edition , 1998 .

[5]  C. Lauer,et al.  InP-based long-wavelength vertical-cavity surface-emitting lasers with buried tunnel junction , 2004 .

[6]  M. Ortsiefer,et al.  InP-based VCSEL technology covering the wavelength range from 1.3 to 2.0 /spl mu/m , 2002, International Conference on Molecular Bean Epitaxy.

[7]  Laurence S. Rothman,et al.  The HITRAN molecular spectroscopic database and HAWKS (HITRAN atmospheric workstation) , 1998, Defense, Security, and Sensing.

[8]  Torsten Latz.  Spektroskopie im Laser-Resonator mit höchster Nachweisempfindlichkeit und spektraler Auflösung , 2000 .

[9]  H. Temkin,et al.  High-speed vertical-cavity surface emitting laser , 1993, IEEE Photonics Technology Letters.

[10]  D. Hovde,et al.  Wavelength modulation detection of water vapor with a vertical cavity surface-emitting laser. , 1997, Applied optics.

[11]  Markus Ortsiefer,et al.  90 C Continuous-Wave Operation of 1.83- m Vertical-Cavity Surface-Emitting Lasers , 2000 .

[12]  C. Lauer,et al.  InP-based VCSEL technology covering the wavelength range from 1.3 to 2.0 μm , 2003 .

[13]  Markus Ortsiefer,et al.  Demonstration of methane spectroscopy using a vertical-cavity surface-emitting laser at 1.68 µm with up to 5 MHz repetition rate , 2003 .

[14]  Markus Ortsiefer,et al.  Spektroskopischer Einsatz neuer langwelliger (bis 2 μm) Diodenlaser (VCSEL) für schwierige Bedingungen (Spectroscopic Application of Long-Wavelength (< 2 μm) VCSEL Diode Lasers) , 2003 .

[15]  M. Ortsiefer,et al.  90/spl deg/C continuous-wave operation of 1.83-μm vertical-cavity surface-emitting lasers , 2000, IEEE Photonics Technology Letters.