Under strong electromagnetic excitation, electron–hole (e-h) pairs may be generated in solids, which are subsequently driven to high energy and high momentum, producing high harmonics (HH) of the driving field. The HH efficiency depends on the degree of coherence between the driven electron and hole created by the laser field. Here, we disrupt this e-h coherence in an atomically thin semiconductor by photodoping via incoherent e-h pairs. We observe a strong, systematic harmonic order-dependent intensity reduction. This trend is explained by an exponential decay of the inter-band polarization, proportional to the sub-cycle excursion time of the e-h pair. Our study provides a platform to probe the importance of many-body effects, such as excitation density-dependent decoherence time for strongly driven electrons without the need of ultrashort laser pulses.

中文翻译：

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使用高次谐波产生探测强驱动二维材料中的电子-空穴相干性

在强电磁激发下，固体中可能产生电子-空穴（eh）对，随后被驱动为高能量和高动量，产生驱动场的高次谐波（HH）。HH 效率取决于激光场产生的驱动电子和空穴之间的相干程度。在这里，我们通过非相干 eh 对的光电掺杂来破坏原子级薄半导体中的这种 eh 相干性。我们观察到强烈的、系统的谐波阶相关强度降低。这种趋势可以通过带间极化的指数衰减来解释，与 eh 对的子周期偏移时间成比例。我们的研究提供了一个平台来探讨多体效应的重要性，