Quantum path contribution to high-order harmonic spectra
Quantum path contribution to high-order harmonic spectra
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DOI：
10.1103/physreva.77.023422
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发表时间：
2008-02
影响因子：
2.9
通讯作者：
E. Brunetti;R. Issac;D. Jaroszynski
中科院分区：
文献类型：
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作者：
E. Brunetti;R. Issac;D. Jaroszynski
持续时间从飞秒到阿秒的超短紫外线和软X射线辐射脉冲可以作为聚焦到气体中的激光束的基频的高次谐波产生。在光谱学和阿秒计量等领域的应用需要控制和表征发射的辐射的光谱和空间特性。这是由单个原子和相互作用介质对激光场的宏观响应共同决定的。在这里，我们提出的证据表明，微观效应具有比先前认为的更大的影响，并可以诱导谐波线的分裂和频移。这些结果不仅为高次谐波的产生提供了直接的诊断，而且使我们能够更好地调整所产生的辐射的参数，同时使我们能够更深入地了解这一非线性光学过程背后的基本物理。
Ultrashort pulses of uv and soft x-ray radiation with durations ranging from femtoseconds to attoseconds can be produced as high-order harmonics of the fundamental frequency of a laser beam focused into gas. Applications to fields such as spectroscopy and attosecond metrology require the control and characterization of spectral and spatial properties of the emitted radiation. These are determined by both single atom and macroscopic response of the interaction medium to the laser field. Here we present evidence that microscopic effects have a larger influence than previously thought, and can induce a splitting and a frequency shift of the harmonic lines. These results not only offer a direct diagnostic for high-order harmonic generation, but also enable us to better tune the parameters of the produced radiation, while giving a deeper insight into the fundamental physics underlying this nonlinear optical process.