Micro/nanoprocessing of graphene surfaces has attracted significant interest for both science and applications due to its effective modulation of material properties, which, however, is usually restricted by the disadvantages of the current fabrication methods. Here, by exploiting cylindrical focusing of a femtosecond laser on graphene oxide (GO) films, we successfully produce uniform subwavelength grating structures at high speed along with a simultaneous in situ photoreduction process. Strikingly, the well-defined structures feature orientations parallel to the laser polarization and significant robustness against distinct perturbations. The proposed model and simulations reveal that the structure formation is based on the transverse electric (TE) surface plasmons triggered by the gradient reduction of the GO film from its surface to the interior, which eventually results in interference intensity fringes and spatially periodic interactions. Further experiments prove that such a regular structured surface can cause enhanced optical absorption (>20%) and an anisotropic photoresponse (~0.46 ratio) for the reduced GO film. Our work not only provides new insights into understanding the laser-GO interaction but also lays a solid foundation for practical usage of femtosecond laser plasmonic lithography, with the prospect of expansion to other two-dimensional materials for novel device applications.

中文翻译：

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高速飞秒激光等离子体光刻和氧化石墨烯还原以实现各向异性光响应。


石墨烯表面的微/纳米加工由于其对材料性能的有效调节而引起了科学和应用的极大兴趣，然而，这通常受到当前制造方法的缺点的限制。在这里，通过利用飞秒激光在氧化石墨烯（GO）薄膜上的柱面聚焦，我们成功地高速生产出均匀的亚波长光栅结构，同时进行原位光还原过程。引人注目的是，明确的结构具有平行于激光偏振的方向和针对不同扰动的显着鲁棒性。所提出的模型和模拟表明，该结构的形成是基于GO薄膜从表面到内部的梯度减小所触发的横向电（TE）表面等离子体激元，最终导致干涉强度条纹和空间周期性相互作用。进一步的实验证明，这种规则的结构化表面可以增强还原后的 GO 薄膜的光吸收（>20%）和各向异性光响应（~0.46 比率）。我们的工作不仅为理解激光-GO相互作用提供了新的见解，而且为飞秒激光等离子体光刻的实际应用奠定了坚实的基础，并有望扩展到其他二维材料的新型器件应用。