Cheng Huachao, Liu Sheng, Li Peng, Liu Feng, Han Lei, Qi Shuxia, Zhong Jinzhan, Guo Xuyue, Zhao Jianlin
Opt Express. 2021 Sep 13;29(19):29766-29779. doi: 10.1364/OE.434363.
We demonstrate a prominent spatial frequency shift (SFS) for the femtosecond laser-induced periodic structures by only changing the polarization ellipticity of the working laser. The nanostructures are fabricated on the surfaces of silicon (Si) and zinc selenide (ZnSe) using elliptically polarized femtosecond laser pulses, with the pulse duration of 35 fs, the central wavelength of 800nm, and the repetition rate of 1kHz. The experimental results show that the red- and blue-shift trends of the SFS are individually represented on silicon and zinc selenide with the increased polarization ellipticity, where low- and high-spatial-frequency nano-ripples are fabricated, respectively. These unique phenomena are explained by using the laser-surface plasmon polariton interference mechanism and the effective medium theory. The proposed nanostructures with regulatable period are further used for creating nano-gratings on silicon which perform chirped characteristics.
我们通过仅改变工作激光的偏振椭圆率，展示了飞秒激光诱导周期性结构的显著空间频率偏移（SFS）。使用椭圆偏振飞秒激光脉冲在硅（Si）和硒化锌（ZnSe）表面制备纳米结构，脉冲持续时间为35 fs，中心波长为800nm，重复频率为1kHz。实验结果表明，随着偏振椭圆率增加，SFS的红移和蓝移趋势分别在硅和硒化锌上体现，其中分别制备了低空间频率和高空间频率的纳米波纹。利用激光 - 表面等离激元极化激元干涉机制和有效介质理论对这些独特现象进行了解释。所提出的具有可调节周期的纳米结构进一步用于在硅上创建具有啁啾特性的纳米光栅。
