基于飞秒激光与纳秒激光协同多光子诱导荧光的火焰中氢原子瞬态检测

Transient detection of hydrogen atoms in flames based on cooperative multiphoton-induced fluorescence with femtosecond and nanosecond lasers

为了准确测量碳氢燃料燃烧过程中原位氢原子,提出了飞秒-纳秒激光协同激发的氢原子瞬态在线探测策略。以243 nm的飞秒激光经过双光子过程将基态氢原子激发到2S能级,随后这些氢原子再被656 nm的纳秒激光激发到3P能级,通过探测3P-2S的荧光发射,实现了宽当量比范围的氢原子无干扰瞬态在线测量。实验结果表明:通过飞秒-纳秒协同的方式,可以有效降低激光光解产生的氢原子对原位氢原子探测的干扰。

In order to accurately measure in-situ hydrogen atoms during the combustion process of hydrocarbon fu-els,this paper proposes a strategy for transient online detection of hydrogen atoms using a femtosecond-nanosecond laser co-excitation method.In this approach,hydrogen atoms in the ground state are excited to the 2S level through a two-pho-ton process using a 243 nm femtosecond laser.Subsequently,these hydrogen atoms are further excited to the 3P level by a 656 nm nanosecond laser,and the fluorescence emission from the 3P-2S transition is detected,enabling interference-free transient online measurement of hydrogen atoms over a wide equivalence ratio range.Experimental results demonstrate that the femtosecond-nanosecond co-excitation method effectively reduces the interference of hydrogen atoms produced by laser photolysis on the detection of in-situ hydrogen atoms.