Femtosecond laser-induced cyano chemiluminescence in methane-seeded nitrogen gas flows for near-wall velocimetry

摘要

We demonstrate a velocimetric technique based on femtosecond laser-induced cyano (CN) chemiluminescence (FLICC). High intensity emission originated from CN(B-X) fluorescence was observed in filaments generated by focusing a femtosecond laser in methane-seeded nitrogen gas flows. The emission is strong and can last for hundreds of microseconds with a proper methane concentration. FLICC was adopted for velocity measurements, and promising results were obtained for near-wall measurements.