共查询到18条相似文献,搜索用时 78 毫秒
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采用空心毛细管束缚强飞秒激光脉冲在高压强气体中产生的成丝时,空心毛细管芯径对光谱展宽有着重要的影响. 研究了空心毛细管束缚成丝时,空心毛细管芯径对光谱展宽的影响. 结果表明,在低能量(0.4mJ)入射时,光谱展宽主要由成丝引起,而在高能量(1.3mJ)入射时,空心毛细管起到光波导效应参与了光谱展宽. 当能量介于二者之间时,采用芯径较小的空心毛细管,可以获得更好的光谱展宽效果.
关键词:
毛细管
成丝
束缚
光谱展宽 相似文献
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激光诊断技术是燃烧温度场无干扰在线测量的主要手段,开发精确的燃烧场温度测量技术对于研究燃烧基础问题具有重要意义.目前,基于激光的燃烧场测温技术大多以纳秒激光作为光源,基于飞秒激光的测温技术相对较少.本文开发了一种基于飞秒激光成丝的燃烧场温度测量方法.飞秒激光在光学介质中传播时,会形成一条具有一维长度且强度均匀分布的光丝,由于光丝内的功率密度极高,足以通过光解和激光诱导光化学反应等方式将原子/分子激发到高能级,进而向低能级跃迁时释放荧光.通过相机收集荧光信号即可获得光丝的空间长度,光丝的长度与光学介质的温度密切相关,将光丝置于已知温度的燃烧场中,可获得不同温度下的光丝长度,结合理论推导,对实验数据进行拟合,可获得光丝长度与温度的定量关系,进而实现燃烧场温度的测量. 相似文献
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测量了线偏振飞秒激光脉冲在空气中成丝产生的氮荧光发射的空间分布.通过改变激光的偏振方向研究成丝过程中氮荧光发射的径向角分布,发现N2+荧光发射在垂直于激光偏振方向上更强,而在平行于激光偏振方向上较弱;N2荧光发射在所有方向上具有近乎相同的强度.原子和分子的激发、电离等动力学过程受激光强度的影响.在飞秒激光成丝过程中沿着激光传播方向,强度呈现先增强后减弱的分布,从而影响这些过程的产物的空间分布及其荧光发射的空间分布.沿着激光传播方向,发现N2荧光先于N2+荧光出现且在N2+荧光消失之后消失.激光强度分布和激光偏振方向均会影响氮荧光的空间分布.基于实验分析,在短焦距情况下,系间窜越过程能很好的解释N2(C3Πu+)的形成,这项研究有助于理解飞秒激光成丝过程中氮荧光发射的产生机制. 相似文献
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Measurement of CO,HCN, and NO productions in atmospheric reaction induced by femtosecond laser filament
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Xiao-Dong Huang 《中国物理 B》2022,31(9):97801-097801
It is proved that the chemical reaction induced by femtosecond laser filament in the atmosphere produces CO, HCN, and NO, and the production CO and HCN are observed for the first time. The concentrations of the products are measured by mid-infrared tunable laser absorption spectroscopy. In the reduced pressure air, the decomposition of CO2 is enhanced by vibration excitation induced by laser filament, resulting in the enhanced production of CO and HCN. At the same time, the CO and HCN generated from the atmosphere suffer rotation excitation induced by laser filament, enhancing their absorption spectra. It is found that NO, CO, and HCN accumulate to 134 ppm, 80 ppm, and 1.6 ppm in sealed air after sufficient reaction time. The atmospheric chemical reaction induced by laser filament opens the way to changing the air composition while maintaining environmental benefits. 相似文献
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本文基于飞秒激光等离子体丝诱导击穿光谱对土壤重金属Cr元素含量进行了实验研究.利用荧光法对等离子体丝的长度进行测量,给出了在不同焦距聚焦透镜作用下土壤中Cr425.5 nm的谱线强度空间分布,实验给出了Cr元素的定标曲线.实验结果表明,土壤中Cr元素浓度分析测量的相对标准偏差小于5%,土壤中重金属Cr元素的检测极限为7.85 ppm.表明飞秒激光等离子体丝诱导击穿光谱技术在土壤重金属Cr元素含量的定量探测方面是完全可行的. 相似文献
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Propagation of bright femtosecond pulses in a nonlinear optical fibre with the third- and fourth-order dispersions
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We solve the generalized nonlinear Schr\"{o}dinger equation
describing the propagation of femtosecond pulses in a nonlinear
optical fibre with higher-order dispersions by using the direct
approach to perturbation for bright solitons, and discuss the
combined effects of the third- and fourth-order dispersions on
velocity, temporal intensity distribution and peak intensity of
femtosecond pulses. It is noticeable that the combined effects of the
third- and fourth-order dispersions on an initial propagated soliton
can partially compensate each other, which seems to be significant
for the stability controlling of soliton propagation features. 相似文献
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Quantum interference in laser-assisted photo-ionization excited by a femtosecond x-ray pulse
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The photoelectron energy spectra (PESs) excited by monochromatic femtosecond x-ray pulses in the presence of a femtosecond laser are investigated. APES is composed of a set of separate peaks, showing interesting comb-like structures. These structures result from the quantum interferences between photoelectron wave packets generated at different times. The width and the localization of each peak as well as the number of peaks are determined by all the laser and x-ray parameters. Most of peak heights of the PES are higher than the classical predictions. 相似文献
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