Simultaneous measurements of temperature and relative concentrations of fuel, oxygen, and nitrogen using combined vibrational coherent anti-Stokes Raman Spectroscopy (CARS) and dual-broad-band rotational CARS have been demonstrated with the use of a Nd:YAG laser and a single dye laser. With the use of a double-folded BOXCARS phase-matching scheme, both the vibrational and the rotational CARS signals were generated in such a way that the signals were superimposed at the spectrograph. With an additional mirror arrangement inside the spectrograph, both signals were recorded simultaneously on a single diode-array detector. The accuracy of single-shot fuel concentration measurements has been investigated, and measurements in a methane/air diffusion flame have been demonstrated. The influence of systematic errors on measured concentrations is discussed.
Per-Erik Bengtsson, Lars Martinsson, and Marcus Aldén, "Combined Vibrational and Rotational CARS for Simultaneous Measurements of Temperature and Concentrations of Fuel, Oxygen, and Nitrogen," Appl. Spectrosc. 49, 188-192 (1995)