In this article, a comparative study is performed to explore the formation mechanism of laser-induced periodic surface structures (LIPSS) using femtosecond laser on silicon carbide (SiC). The optical properties of SiC transformed to a metal-like state when the excited carrier density exceeds 2e22 cm−3 under laser irradiation and significantly altered the laser energy deposition. The laser-induced carrier density coupled with the optical properties and the incident laser intensity profile were calculated. The two-temperature model was used to describe the energy transformation from electron to lattice and guided to select appropriate laser conditions for producing ripples. The spatial period of laser-induced periodic nanostructures was calculated in frequency domain based on the Drude-Sipe model that comprised the estimation of free carrier density. The calculated range of the spatial period of LIPSS was about from 776 to 544 nm. Additionally, the experimental value was about 719–483 nm, which contained a good consistency with the theoretical results. This work provides a new approach for the prediction and fabrication of the LIPSS on SiC.

中文翻译：

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飞秒激光诱导碳化硅波纹形成机理的组合模型

在本文中，进行了比较研究，以探索使用飞秒激光在碳化硅 (SiC) 上形成激光诱导周期表面结构 (LIPSS) 的机制。当激发载流子密度在激光照射下超过 2e22 cm-3 时，SiC 的光学性质转变为类金属状态，并显着改变了激光能量沉积。计算了激光诱导的载流子密度与光学特性和入射激光强度分布。双温度模型用于描述从电子到晶格的能量转换，并引导选择合适的激光条件来产生波纹。基于包含自由载流子密度估计的 Drude-Sipe 模型，在频域中计算激光诱导的周期性纳米结构的空间周期。LIPSS 空间周期的计算范围约为 776 至 544 nm。此外，实验值约为 719-483 nm，与理论结果具有良好的一致性。这项工作为预测和制造 SiC 上的 LIPSS 提供了一种新方法。