Single-laser-shot detection of nitric oxide in reacting flows using electronic resonance enhanced coherent anti-Stokes Raman scattering

Abstract

Single-laser-shot electronic resonance enhanced coherent anti-Stokes Raman scattering (ERE-CARS) spectra of nitric oxide (NO) were generated using the 532 nm output of an injection-seeded Nd:YAG (yttrium aluminum garnet) laser as the pump beam, a broadband dye laser at approximately 591 nm as the Stokes beam, and a 236 nm narrowband ultraviolet probe beam. Single-laser-shot ERE-CARS spectra of NO were acquired in an atmospheric-pressure hydrogen/air counterflow diffusion flame. The single-shot detection limit in this flame was found to be approximately 30 ppm, and the standard deviation of the measured NO concentration was found to be approximately 20% of the mean.