Author(s)

Anatoliy Y Vorobyev, Chunlei Guo

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A detailed study on correlation between residual thermal response of a sample and its optical absorptance change due to laser-induced sur-face structural modifications in multi-shot fem-tosecond laser irradiation is performed. Ex-periments reveal an overall enhancement for residual thermal coupling and absorptance in air. Surprisingly, residual thermal coupling in air shows a non-monotonic dependence on pulse number and reaches a minimum value after a certain number of pulses, while these behaviors are not seen in absorptance. In vacuum, how-ever, both suppression and enhancement are seen in residual energy coupling although ab-sorptance is always enhanced. From these ob-servations, it appears that air plasma plays a dominant role in thermal coupling at a relatively low number of applied pulses, while the forma-tion of craters plays a dominant role at a high number of pulses.

Femtosecond Laser; Ablation; Residual Energy; Absorptance; Surface Structures

Vorobyev, A. and Guo, C. (2011) Thermal response and optical absorptance of metals under femtosecond laser irradiation. Natural Science, 3, 488-495. doi: 10.4236/ns.2011.36068.