超快复合脉冲烧蚀硅表面的偏振依赖性研究(特邀)  

Study on Polarization Dependence of Ultrafast Combination Pulse Ablation on Silicon Surface(Invited)

作　　者：史慧强 姚倩 尹唯一 苏子怀 余江 宋娟[2] 林贤[1] 戴晔[1] SHI Huiqiang;YAO Qian;YIN Weiyi;SU Zihuai;YU Jiang;SONG Juan;LIN Xian;DAI Ye(Department of Physics,Shanghai University,Shanghai 200444,China;School of Material Science and Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]上海大学物理系,上海200444 [2]江苏大学材料科学与工程学院,镇江212013

出　　处：《光子学报》2023年第7期28-35,共8页Acta Photonica Sinica

基　　金：国家自然科学基金(Nos.12274280,11774220,11974147)。

摘　　要：以晶面<100>的硅片为研究对象,使用重复频率1 kHz的超快复合双脉冲作为激发工具,通过研究双脉冲之间的偏振夹角、延迟时间和脉冲数对周期性结构面积的影响,探究引起周期性结构演化的非线性电离动力学。实验结果表明,在激光能量密度为0.23 J/cm2、脉冲组合为100个的复合脉冲辐照条件下,正交偏振诱导的结构面积最小,相比于其他入射形式下诱导的最大面积减小率约为45%,这是因为局域场的反复调制抑制了周期性结构边缘烧蚀阈值的降低。在正交偏振时,随着两束脉冲之间延迟时间的改变,通过观察诱导结构面积变化可以分析从电子电离到物质喷发的连续过程。该复合脉冲调控技术可为研究超快激光诱导半导体表面周期性结构的偏振依赖性与电子电离效率提供参考,进一步的改进有望实现超衍射极限结构的快速诱导。Since the invention of the laser,a great deal of research has focused on the mechanisms of laser-silicon interactions.Although ultrafast laser processing of Laser Induced Periodic Surface Structures(LIPSS)structures on silicon surfaces has been carried out for a long time,there are still problems,such as low processing efficiency in the preparation of large-area structures.The use of double pulse sequences has therefore been tried to improve the quality and efficiency of the process and has proved to be an effective strategy.A new method was provided for enhanced energy deposition by irradiating a ZnO surface with a Fs+Ps Double-Pulse Sequence(FPDPS)with a combined pulse width of 120 fs+2 ps and a sub-pulse energy ratio of 1∶1.On this basis,we investigate the nonlinear ionization dynamics causing the evolution of periodic structures by studying the effect of polarization angle,delay time and number of pulses between the double pulses on the area of the periodic structure,using an ultrafast combination double pulse with a repetition frequency of 1 kHz as an excitation tool on a silicon wafer with a crystalline surface of<100>.The experimental results show that under the combined pulse irradiation condition with a laser energy density of 0.23 J/cm2 and pulse combination of 100 pulses,there is a“V”shaped variation pattern at all delays within±50 ps.The structure area induced by orthogonal polarization is the smallest,and the maximum area reduction rate is about 45%compared to that induced by other incident forms.This is due to the repeated modulation of the local field suppressing the reduction of the periodic structural edge ablation threshold.Specifically,the first pulse forms a LIPSS structure at the center and produces a local field modulated by polarization.When the two pulses are polarized in the same direction,subsequent pulses will gradually strengthen the initial local field,forming an elliptical distribution of stable local field strengths,which will effectively promote the growth of the LIPSS struc

关 键 词：超快光学 超快复合脉冲 偏振依赖性 局域场调控 硅 电离过程 

分 类 号：O437[机械工程—光学工程]