Investigation of NO detection in flames by the use of polarization spectroscopy

Various aspects of detection of NO molecules in a premixed H(2)/N(2)O flame were investigated by the use of polarization spectroscopy. The signals were recorded in the A(2)Σ(+)-X(2)II (0, 0) band of NO at 226 nm. Excitation spectra for circularly and linearly polarized pump beams are presented to illustrate the influence of the polarization state. The signal dependencies on the pump- and the probe-beam intensities were also investigated, as well as the influence of the setup geometry with respect to the pump-beam focusing and the crossing angle between the pump and the probe beams. A preliminary evaluation of temperature based on spectra recorded by the use of the Boltzmann plotting approach was performed. Finally the possibilities of two-dimensional imaging of the NO molecules were demonstrated.