Generation of ultrabroadband terahertz radiation under optical breakdown of air by two femtosecond pulses of different frequencies
Generation of ultrabroadband terahertz radiation under optical breakdown of air by two femtosecond pulses of different frequencies
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两个不同频率的飞秒脉冲在空气光击穿下产生超宽带太赫兹辐射
DOI：
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发表时间：
2009
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通讯作者：
S. Stumpf
中科院分区：
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作者：
A. Andreev;V. Bespalov;Andrei Gorodetsky;S. Kozlov;V. Krylov;G. V. Lukomskiĭ;E. Novoselov;N. Petrov;S. Putilin;S. Stumpf
利用钛宝石激光器的基频和二次谐波飞秒脉冲电离空气产生太赫兹电磁辐射的实验结果。产生的太赫兹辐射的平均功率作为两个不同频率的脉冲之间的时间延迟的函数被发现是准周期性的。从理论上讲，我们表明，有效地产生太赫兹辐射是由惯性部分的非线性响应的介质，这是由人口动态的高激发态与随后的电子发射。
Experimental results on the generation of terahertz (THz) electromagnetic radiation under ionization of air by femtosecond pulses at fundamental and second-harmonic frequencies of a Ti-sapphire laser are presented. The mean power of the generated THz radiation as a function of the time delay between two pulses of different frequencies is found to be quasi-periodical. Theoretically, we show that efficient generation of THz radiation is governed by the inertial part of the nonlinear response of the medium, which is determined by the dynamics of population of highly excited states with subsequent emission of electrons.