Spatial averaging and multiplex coherent anti-Stokes Raman scattering temperature-measurement error

We discuss the effect of spatial averaging within the probe volume on multiplex coherent anti-Stokes Raman scattering temperature measurements. A numerical simulation and an experimental verification on a small laminar flame burner were performed. Appreciable measurement errors can be made in reactive laminar or turbulent media with large gradients. The errors, which are caused by biasing in favor of cold gases, increase with the temperature difference.