Product Code: ICA10_M303

Ultrashort Pulse Periodic Surface Structuring of Metallic Surfaces
Authors:
Leigh Mellor, The University of Liverpool; Liverpool Great Britain
Stuart P. Edwardson, The University of Liverpool; Liverpool Great Britain
Walter Perrie, The University of Liverpool; Liverpool Great Britain
Geoff Dearden, The University of Liverpool; Liverpool Great Britain
Ken Watkins, The University of Liverpool; Liverpool Great Britain
Presented at ICALEO 2010

The surfaces of a range of metallic materials have been modified through laser illumination. Modification of the surfaces was attributed to the interference of the incident beam with a surface scattered wave resulting in the production of Laser Induced Periodic Surface Structures (LIPSS). The resulting features gave a self ordering ripple pattern with feature sizes of the order of the wavelength. Such features were first recorded during the 1960s and have since been observed in a wide range of materials leading to a number of possible mechanisms for their existence. In this work two high frequency picosecond pulsed fibre laser systems were used with pulse lengths of ~25 and ~60ps respectively. Machining was carried out utilising a range of parameters, including incident beam angle, in order to optimise the uniformity of features produced. Thresholds for the production of high quality ripple formations were found for varying pulse overlap and pulse lengths. Potential applications of this structuring method include modification of wetting angle, particularly if combined with micro scale features.