Probing ultrafast nonequilibrium dynamics in single-crystal SiC through surface nanostructures induced by femtosecond laser pulses

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	Probing ultrafast nonequilibrium dynamics in single-crystal SiC through surface nanostructures induced by femtosecond laser pulses
	He, W. L. and J. J. Yang
刊名	Journal of Applied Physics
	2017
卷号	121 期号:12
英文摘要	Ultrafast non-equilibrium dynamics on the surface of a 4H-SiC crystal is experimentally investigated with time-delayed copropagating two femtosecond laser pulse trains of different linear polarizations. Rippled nanostructures are produced by this irradiation, and the alignment "slant" angle of the ripples is related to the polarizations. With varying time delays between the two laser pulses, this slant angle is found to change. In the first 10 ps, the slant quickly rotates in the direction associated with the polarization of the second incident laser pulse, but then abruptly freezes to a steady offset angle. A physical model is proposed to explain the underlying mechanisms. The first laser pulse produces a transient grating-like modulation of the dielectric constant on the surface, with which the second laser pulse interacts. Because competing fast (Auger) and slow (thermal) relaxation processes reduce the initially induced grating's dielectric constant difference, the vector sum of this partially evolved grating with the second laser pulse's interaction results in the observed slant rotation time dependence. This experiment is straightforward, conceptually simple, and utilizes commercial equipment. The time-resolved slanting of the ripple orientation provides an alternative description of the spatiotemporal evolution of a superheated semiconductor surface. Published by AIP Publishing.
语种	英语
内容类型	期刊论文
源URL	[http://ir.ciomp.ac.cn/handle/181722/58938]
专题	长春光学精密机械与物理研究所_中科院长春光机所知识产出
推荐引用方式 GB/T 7714	He, W. L. and J. J. Yang. Probing ultrafast nonequilibrium dynamics in single-crystal SiC through surface nanostructures induced by femtosecond laser pulses[J]. Journal of Applied Physics,2017,121(12).
APA	He, W. L. and J. J. Yang.(2017).Probing ultrafast nonequilibrium dynamics in single-crystal SiC through surface nanostructures induced by femtosecond laser pulses.Journal of Applied Physics,121(12).
MLA	He, W. L. and J. J. Yang."Probing ultrafast nonequilibrium dynamics in single-crystal SiC through surface nanostructures induced by femtosecond laser pulses".Journal of Applied Physics 121.12(2017).