中文摘要：

激光干涉加工是一种实现周期性微纳米结构制造的高效、低成本加工的新工艺。研究硅表面亚微米结构多激光束干涉加工工艺。分析多光束干涉光强分布的周期性分布特征,多光束干涉光强分布可在微小区域内获得高分辨率的光强分布,有利于高质量的周期性微结构的加工。采用基于二维位相光栅分束方法的四光束干涉试验系统,采用纳秒短脉冲激光束,以单晶硅材料为研究对象,进行多光束干涉试验。试验结果表明,采用四光束干涉,可在硅材料表明加工出周期性亚微米圆点锥状阵列结构,并且周期性规律与光强分布相同;结合短脉冲激光材料去除中熔化、汽化、直接汽化三个临界阈值,分析四光束干涉圆点阵列结构的形成机理;当脉冲数量增加时,圆点阵列高度增大并逐渐饱和,当脉冲数目较多时,在圆点顶部会产生由于表明张力引起熔池流动形成的微小圆粒。

英文摘要：

Laser interference structuring is a relatively efficient and cost-effective technique for fabricating periodical micro-nano structures. The direct fabrication of sub-micron sized dot array on silicon is performed by four interfering nanosecond laser beams with diffractive beam splitter. It is found that the obtained conical dot array has a negative shape of the interference pattern of four laser beams. And the height at the hotter regions is a litter higher than the root of the conical dots due to the liquid-solid expansion. In addition, the influence of laser pulse number on the dot shape is studied. Beams at the top of dots can be induced for a large number of pulses. The dot height is found to grow with the increase of laser pulse number, but the saturation can be observed when the pulse number is large enough.