How to obtain the high signal intensity harmonic spectra with the single harmonic radiation path contribution becomes an important issue in the investigations of the high-order harmonic generation and attosecond science. In this paper, through the nonhomogeneous multicolor laser beams optimization, the best time-spatial laser waveforms, including the positive and negative time-spatial waveforms, to produce the harmonic spectra can be found. As a result, the harmonic plateaus with the single harmonic radiation path contribution and with the enhancement of several orders of magnitudes can be obtained, which can support the generation of the isolated pulses with the durations of 29 as. The physical mechanism behind the improvement of the harmonic spectra is given by the time-spatial profile analyses of the laser pulses and the harmonic spectra.

中文翻译：

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非均匀多色激光束优化以获得更强强度的单次谐波辐射路径

如何获得具有单次谐波辐射路径贡献的高信号强度谐波光谱成为高次谐波产生和阿秒科学研究中的一个重要问题。在本文中，通过非均匀多色激光束优化，可以找到产生谐波光谱的最佳时空激光波形，包括正时空波形和负时空波形。结果，可以获得具有单次谐波辐射路径贡献和几个数量级增强的谐波平台，可以支持持续时间为29as的孤立脉冲的产生。谐波光谱改善背后的物理机制由激光脉冲和谐波光谱的时空分布分析给出。