ISSN:
1432-0649
Keywords:
82.40.Py
;
07.20.Dt
;
07.65.-b
;
33.20.Lg
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract We report the use of Degenerate Four-Wave Mixing (DFWM) in the OHA 2 Σ + ←X 2 ∏ (υ′ = 0 ←υ″ = 0) band for temperature determination in a propane/air flame using laser powers below the saturation level. We show that at these low power levels the dependence of the signal on the dipole moment for the transition has to be established before meaningful temperature data can be obtained. This presents a paradox in that the temperature has to be known before the form of the dependence on the dipole moment can be determined. Solutions to this paradox are presented. We also show that absorption of the laser beams in this OH band system cannot be neglected and that failure to correctly account for the absorption leads to a large over estimate of the flame temperature. Furthermore, we show that the accuracy of the absorption-corrected temperature is critically dependent on the accuracy with which the measurement position within the flame is known. Finally, the temperature calculated from DFWM spectra using the correct dipole moment power and absorption is compared to the temperatures obtained using Laser-Induced Fluorescence (LIF) and Coherent Anti-Stokes Raman Spectroscopy (CARS).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01081076
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