High-harmonic generation from an epsilon-near-zero material
High-harmonic generation from an epsilon-near-zero material
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DOI：
10.1038/s41567-019-0584-7
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发表时间：
2019-02
期刊：
影响因子：
19.6
通讯作者：
Yuanmu Yang;Jian Lu;A. Manjavacas;T. Luk;Hanzhe Liu;K. Kelley;J. Maria;Evan L. Runnerstrom
中科院分区：
文献类型：
--
作者：
Yuanmu Yang;Jian Lu;A. Manjavacas;T. Luk;Hanzhe Liu;K. Kelley;J. Maria;Evan L. Runnerstrom
高谐波产生（HHG）是强驱动非线性光学系统的典型光学现象。具体来说，对稀有气体中HHG过程的理解在阿秒科学的发展中发挥了关键作用。最近，HHG在固体中也有报道，提供了新的机会，例如将密集光学介质中的强场和阿秒过程控制到纳米级。在这里，我们通过利用epsilon-near-zero （ENZ）效应，，，，-报道了低损耗，铟掺杂的氧化镉薄膜的HHG，其中材料的介电常数的实部在某些光谱范围内消失，以及相关的驱动激光场的大共振增强。我们发现ENZ辅助谐波表现出明显的光谱红移和线宽增宽，这是由于光诱导电子加热和随之而来的随时间变化的材料ENZ波长造成的。我们的研究结果为研究ENZ材料中的强场和超快电子动力学提供了一个新的平台，揭示了HHG光谱和时间控制的新自由度，并开辟了紧凑的固态阿秒光源的可能性。
High-harmonic generation (HHG) is a signature optical phenomenon of strongly driven, nonlinear optical systems. Specifically, the understanding of the HHG process in rare gases has played a key role in the development of attosecond science. Recently, HHG has also been reported in solids, providing novel opportunities such as controlling strong-field and attosecond processes in dense optical media down to the nanoscale. Here, we report HHG from a low-loss, indium-doped cadmium oxide thin film by leveraging the epsilon-near-zero (ENZ) effect, , , , –, whereby the real part of the material’s permittivity in certain spectral ranges vanishes, as well as the associated large resonant enhancement of the driving laser field. We find that ENZ-assisted harmonics exhibit a pronounced spectral redshift as well as linewidth broadening, resulting from the photo induced electron heating and the consequent time-dependent ENZ wavelength of the material. Our results provide a new platform to study strong-field and ultrafast electron dynamics in ENZ materials, reveal new degrees of freedom for spectral and temporal control of HHG, and open up the possibilities of compact solid-state attosecond light sources.