为了研究飞秒激光诱导的硅材料周期表面结构,采用了理论分析和实验验证相结合的方法,对波纹周期与入射激光波长之间关系的理论分析计算,得到了单晶硅表面波纹周期约为800nm,研究了1kHz的飞秒脉冲(中心波长800nm,脉宽35fs)加工单晶硅引起的波纹结构.结果表明,在功率密度略大于样品损伤阈值的条件下,单晶硅表面形成了清晰的平行等间距直线周期条纹结构,测得该条纹的周期约为750nm,与所用激光中心波长接近.使用可旋转的格兰-泰勒棱镜改变入射激光的偏振方向,发现周期波纹方向随入射激光偏振方向的改变而改变,条纹方向与飞秒激光的电矢量方向垂直,并且由加工图片看出经辐照过的区域比未经辐照区域干净得多.这一结果对进一步研究激光诱导的周期性表面结构具有参考意义.

In order to study periodic structures on Si surface induced by femtosecond laser,the relationship between the ripple period and the incident laser wavelength was analyzed.After theoretical analysis and experimental verification,the ripple period of monocrystalline silicon was calculated to be about 800nm.The ripple structures irradiated by 1kHz femtosecond pulses (center wavelength of 800nm,pulse width of 35fs) were studied.The results show that a set of liner ripple structure with parallel and equal spaces is found on the silicon surface irradiated by pulse laser under the condition that power density is slightly higher than damage threshold of the workpiece.The period of ripples is about 750nm by measurement,close to the center wavelength of laser.When the polarization direction of incident laser is changed by a rotatable Glan-Taylor prism,the direction of periodic ripples is changed accordingly.The direction of ripple is perpendicular to the electric vector direction of the femtosecond laser.The processing images show that the irradiated area is much cleaner than the non-irradiated area.The investigation is significant for further study of laser-induced periodic surface structures.