Simple determination of the width of the slit function in single-shot coherent anti-Stokes Raman spectroscopy

Abstract

The determination of temperatures using single-shot coherent anti-Stokes Raman spectroscopy normally requires an accurate measurement of the instrument slit function. This slit function is normally determined at a known temperature, and then assumed to be the applicable function at all temperatures and independent of the optical path which varies with density or temperature gradients. In this communication we show a simple method of determining the width of the slit function from the collected data at the actual temperature and turbulence level. This method depends on local thermodynamic equilibrium and is a generally applicable technique to determine the instrument slit function. It is limited to temperatures in excess of 1100 K, as it requires that there be a nonzero signal in the v=1 vibrational level of N2.