Femtosecond laser-induced shockwave formation on ablated silicon surface

This paper reports an experimental study of the vapor plume and shockwave propagation generated during femtosecond laser ablation. An Yb-doped fiber amplified/oscillator laser with 1030 nm wavelength and pulse repetition rate up to 26 MHz was used to ablate a blank silicon substrate in an ambient air environment. The interaction of internal and external shockwaves with the sample surface was found to cause raised spherical rims around the central ablation regime within the crater. Rims formed by primary and secondary shockwaves can be clearly observed. Analysis of the rim formation is studied in detail. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3122047]