A laser-induced fluorescence scheme for imaging nitric oxide in engines

Laser-induced fluorescence of nitric oxide is commonly used for the detection of this major pollutant in combustion processes. Mostly, excitation within the A-X(0, 0) band is used next to excitation of the D-X(0, 1) band. However, for real engine applications strong absorption of the laser beam prevents the application of these schemes. Exciting in the A-X(0, 2) band circumvents these problems and allows the sensitive two-dimensional detection of nitric oxide in engines fueled with iso-octane or diesel fuel. The spectroscopy of this detection scheme and the experimental apparatus used to generate the required laser energy are reported.