Coherent control for species selectivity in a flat-flame using femtosecond/picosecond coherent Raman scattering

Coherent control for the selective spectral suppression of combustion species using femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps CARS) is presented. Phase modulation of one of the excitation pulses was accomplished using a 4- f pulse shaper with a spatial light modulator at the Fourier plane. A feedback-controlled genetic algorithm was used to search for the appropriate modulated waveform in a non-reacting gas jet of known composition; the selected phase function was subsequently applied in a H 2 /air flat-flame diluted with CO 2 . Q-branch transitions of O 2 and CO 2 were targeted. To our knowledge, this is the first demonstration of coherent control using fs/ps CARS for spectral species selectivity in a combustion environment. • First demonstration of coherent control with fs/ps CARS in a flame. • Optimal phase functions experimentally determined before application in a flame. • Amplification or annihilation of targeted rovibrational transitions was achieved.