Nanoscale surface boiling in sub-threshold damage and above-threshold spallation of bulk aluminum and gold by single femtosecond laser pulses

作者：Ionin Andrey A; Kudryashov Sergey I; Makarov Sergey V; Levchenko Alexey O; Rudenko Andrey A; Saraeva Irina N; Zayarny Dmitry A; Nathala Chandra R; Husinsky Wolfgang

来源：Laser Physics Letters, 2016, 13(2): 025603.

DOI：10.1088/1612-2011/13/2/025603

• aluminum
• gold
• femtosecond laser ablation
• spallation
• boiling
• plasmonics
• biosensing

The sub and near-threshold topographic signatures of the spallation of nanometer-thick melt layers during single-shot femtosecond laser ablation of bulk aluminum and gold were experimentally observed for the first time, using scanning electron microscopy with high spatial resolution. The novel ablative nanofeatures-sub-threshold boiling nanopits, the partially detached ultrathin solidified melt layer, and the lamellar surface structure under the layer along the spallative crater border, as well as the foam-like nanostructure of the crater bottom-indicate the boiling origin of the spallation threshold, rather than the thermomechanical rupture of the molten surface layer in a propagating unloading wave. These ablative surface nanofeatures were also revealed in trenches of single-shot, near-wavelength normal interference ripples on the aluminum surface, indicating their spallative nature and being promising for biosensing applications.

• 出版日期2016-2