Laser-induced periodic surface structures on 6H-SiC single crystals using temporally delayed femtosecond laser double-pulse trains
Laser-induced periodic surface structures on 6H-SiC single crystals using temporally delayed femtosecond laser double-pulse trains
复制标题
DOI：
10.1007/s00339-016-9918-9
复制
发表时间：
2016-03
期刊：
影响因子：
--
通讯作者：
Juan Song;Wenjun Tao;Hui Song;M. Gong;G. Ma;Ye Dai;Quanzhong Zhao;J. Qiu
中科院分区：
文献类型：
--
作者：
Juan Song;Wenjun Tao;Hui Song;M. Gong;G. Ma;Ye Dai;Quanzhong Zhao;J. Qiu
采用马赫-曾德尔干涉仪等共线双光束光学系统产生的波长为800 nm、脉宽为200 fs、重复频率为1 kHz的延时可调双脉冲序列辐照6 H-SiC晶体。研究了平行极化结构下双脉冲序列时间延迟对诱导结构的影响。结果表明，随着共线平行偏振双脉冲序列时延的增加，诱导的近亚波长波纹（NSWR）由不规则的波纹模式转变为规则的周期性模式，且波纹的沟槽加深。这种转变的特征时间尺度约为6.24 ps。此外，NSWR面积在0 ~ 1.24ps时延范围内呈指数衰减，在1.24 ~ 14.24ps时延范围内缓慢增大。分析表明，多光子电离效应、光栅辅助的表面等离子体耦合效应以及第二脉冲对6 H-SiC在第一脉冲辐照后所经历的某一物理阶段的及时干预可能有助于形貌细节的转变。
In this paper, a time-delay-adjustable double-pulse train with 800-nm wavelength, 200-fs pulse duration and a repetition rate of 1 kHz, produced by a collinear two-beam optical system like a Mach–Zehnder interferometer, was employed for irradiation of 6H-SiC crystal. The dependence of the induced structures on time delay of double-pulse train for parallel-polarization configuration was studied. The results show that as the time delay of collinear parallel-polarization dual-pulse train increased, the induced near-subwavelength ripples (NSWRs) turn from irregular rippled pattern to regularly periodic pattern and have their grooves much deepened. The characteristics timescale for this transition is about 6.24 ps. Besides, the areas of NSWR were found to decay exponentially for time delay from 0 to 1.24 ps and then slowly increase for time delay from 1.24 to 14.24 ps. Analysis shows that multiphoton ionization effect, grating-assisted surface plasmon coupling effect, and timely intervene of second pulse in a certain physical stage experienced by 6H-SiC excited upon first pulse irradiation may contribute to the transition of morphology details.