Improvement in Temperature Measurement Accuracy of Q-Branch CARS Thermometry : Effects of Spectral Resolution of Detection System

Abstract

The temperature measurement accuracy of N₂ Q-branch CARS (Coherent Anti-Stokes Raman Spectroscopy) below 1000K has been improved by improving the spectral resolution of the detection system. The total spectral resolution was improved from 1. 3cm^-1 to 0. 6cm^-1 by dispersion magnification (×3. 6), which was effected by adding a magnifier between a monochromator and an intensified photodiode array detector. The accuracy of temperature measurement in the temperature range of 300-800K for pressures of 0. 1-3. 0MPa has been greatly improved from ±100K, in the case without the magnifier, to ±40K. The method reported in this paper has a potential advantage for practical use because of its convenience.