Determination of temperature and concentration of molecular nitrogen, oxygen and methane with coherent anti-stokes raman scattering

Abstract

Temperature and concentration measurements by Coherent Anti-Stokes Raman Scattering (CARS) of molecular nitrogen, oxygen and methane were carried out. A comparison of corrected thermocouple and CARS temperature measurements in a high-temperature furnace up to 2000 K is presented. The temperature dependent CARS spectra of N2 and O2 are evaluated by a simulation program. Agreement between CARS and thermocouple temperatures is obtained within 40 K for N2 and 80 K for O2. Good agreement is found between measurements and calculations of the decrease of CARS intensity with temperature. Various “quick-fit” methods for N2-and O2-temperature measurements from temperature sensitive spectral parameters were tested. Temperature dependent CARS spectra of thev1-fundamental of methane are recorded and the methane CARS intensity as function of temperature is measured.