通过实验研究了超快激光诱导亚波长周期结构表面形貌的变化和调控, 利用1 064 nm皮秒激光和800 nm飞秒激光辐照金属钛, 通过改变脉冲个数和激光辐照方式, 研究孵化效应在亚波长表面周期结构产生过程中的影响。研究发现: 1)亚波长周期结构区域、烧蚀区域和亚波长表面结构周期均随着皮秒激光脉冲个数的增加而增大, 但是增加相同的脉冲个数, 因孵化效应的作用使其增幅不同; 2)改变激光辐照方式可有效增大亚波长表面周期结构面积的同时可制备更精细的亚波长周期结构: 亚波长周期结构区域和烧蚀区域直径在辐照方式为N=500+1000和N=1000+500情况下均有增大, 同时前序脉冲个数较少后序脉冲个数较多的情况下(如N=500+1000), 增幅更大; N=500+1000和N=1000+500辐照情况下其亚波长表面周期小于N=1500的情况。由此可知, 综合考虑脉冲个数、激光辐照方式和孵化效应的影响, 通过分序两步法可有效调控亚波长表面周期结构的形貌, 提高亚波长表面周期结构的制备效率和质量, 可高效制备高质量大面积一致性亚波长表面结构。

In this study, the adjustments and changes of subwavelength ripples induced by ultrafast laser on titanium are experimentally investigated. In our experiments, 1064 nm picosecond laser and 800 nm femtosecond laser are used to irradiate the surface of metal titanium. The effects of incubation on the formation of subwavelength ripples are studied by changing pulse number and irradiation modes. The experimental results show that: 1) the overall trend of ripples areas, ablated areas and periods of rippled structures increases as the number of pulses increases; 2) due to the incubation effects, the increase is different; 3) by designing laser pulse irradiation modes, samples firstly irradiated by several shots and then by remaining shots, have better surface morphologies. Hence, large-area, uniform rippled structures can be adjusted by designing laser pulse modes and pulse number.