The reorientation of 2D materials caused by nonlocal electron coherence is the formation mechanism of 2D material spatial self-phase modulation under laser irradiation, which is widely known as the “wind-chime” model. Here, we present a method that provides strong evidence for the reorientation of 2D-material-induced spatial self-phase modulation. The traditional “wind-chime” model was modified by taking into account the attenuation, i.e., damping of the incident light beam in the direction of the optical path. Accordingly, we can extract the nonlinear refractive index of a single MoS2 nanosheet, instead of simply obtaining the index from an equivalent MoS2 film that was constructed by all nanosheets. Our approach introduces a universal and accurate method to extract intrinsic nonlinear optical parameters from 2D material systems.

中文翻译：

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揭示基于空间自相位调制的悬浮液中单个二硫化钼纳米片的本征非线性光学响应

由非局域电子相干引起的二维材料的重新定向是激光照射下二维材料空间自相位调制的形成机制，被广泛称为“风铃”模型。在这里，我们提出了一种方法，该方法为二维材料诱导的空间自相位调制的重新定向提供了强有力的证据。传统的“风铃”模型通过考虑衰减，即入射光束在光路方向上的衰减进行了修改。因此，我们可以提取单个 MoS2 纳米片的非线性折射率，而不是简单地从由所有纳米片构成的等效 MoS2 薄膜中获得折射率。我们的方法引入了一种通用且准确的方法来从 2D 材料系统中提取固有的非线性光学参数。