激光脉宽和偏振效应对飞秒光丝诱导燃烧中间产物荧光光谱的影响

Effects of Pulse Duration and Polarization on Femtosecond Filament-Induced Fluorescence of Combustion Intermediates

聚焦激光脉宽和偏振对飞秒光丝诱导燃烧场中间产物荧光光谱的影响,通过改变激光脉宽、偏振状态,观测了燃烧中间产物如OH、CH、CN、C2分子和C原子的荧光光谱变化。结果发现:随着激光脉宽和偏振椭圆率增大,各组分荧光信号强度减小,这是因为光丝内激光钳制强度及等离子的密度与激光脉宽、偏振密切相关,进而导致多光子激发燃烧中间产物的信号随之变化。

The effects of laser pulse duration and polarization on the femtosecond filament-induced fluorescence of combustion intermediates were studied herein. The variations in the fluorescence spectra of combustion intermediates, such as OH, CH, CN, C2, and C, were observed by varying laser pulse duration and polarization. The results show that the fluorescence intensities of all the observed combustion intermediates decrease with the increase of laser pulse duration and polarization ellipticity. This behavior is explained by the fact the clamped intensities and plasma densities inside the filament core are strongly dependent on laser pulse duration and polarization, leading to the changes in the multiphoton-excited signals of combustion intermediates.