Ultraviolet Femtosecond and Nanosecond Laser Ablation of Silicon: Ablation Efficiency and Laser-Induced Plasma Expansion.

Zong, X. ; Mao, X. ; Greif, R. ; Russo, R. E.

Technical Information Center Oak Ridge Tennessee

关键词: Laser-induced plasma;    Shock wave;    Electrons;    Plasma;    Plasma expansion;   

RP-ID  :  DE2005836676

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Femtosecond laser ablation of silicon in air was studied and compared with nanosecond laser ablation at ultraviolet wavelength (266 nm). Laser ablation efficiency was studied by measuring crater depth as a function of pulse number. For the same number of laser pulses, the fs-ablated crater was about two times deeper than the ns-crater. The temperature and electron number density of the pulsed laser-induced plasma were determined from spectroscopic measurements. The electron number density and temperature of fs-pulse plasmas decreased faster than ns-pulse plasmas due to different energy deposition mechanisms. Images of the laser-induced plasma were obtained with femtosecond time-resolved laser shadowgraph imaging. Plasma expansion in both the perpendicular and the lateral directions to the laser beam were compared for femtosecond and nanosecond laser ablation.