Product Code: ICA12_M303

Picosecond Laser Beam Shaping Using a Spatial Light Modulator
Authors:
Dun Liu, School of Mechanical Engineering, Hubei Univ. of Technology, Laser Group, School of Engineering, Univ. of Liverpool; Liverpool Great Britain
Walter Perrie, Laser Group, School of Engineering, Univ. of Liverpool; Liverpool Great Britain
Leigh Mellor, Laser Group, School of Engineering, Univ. of Liverpool; Liverpool Great Britain
Zheng Kuang, Laser Group, School of Engineering, Univ. of Liverpool; Liverpool Great Britain
Eamonn Fearon, Laser Group, School of Engineering, Univ. of Liverpool; Birkenhead Great Britain
Stuart Edwardson, Laser Group, School of Engineering, Univ. of Liverpool; Liverpool Great Britain
Geoff Dearden, Laser Group, School of Engineering, Univ. of Liverpool; Liverpool Great Britain
Ken Watkins, Laser Group, School of Engineering, Univ. of Liverpool; Liverpool Great Britain
Presented at ICALEO 2012

A beam shaping technique, which is capable of converting a Gaussian beam to an arbitrary 3D beam profile through the implementation of a phase-only Spatial Light Modulator (SLM) combined with polarising optics, is presented. A beam profiling camera provides visualisation of beam alterations, which allowed for control over beam shape and intensity distribution in real time. Various beam profiles can be created for different applications. An investigation into the production of laser induced periodic surface structures (LIPSS) with a square flat-top beam shows potential improvement of LIPSS uniformity over a Gaussian beam. It is believed that the combination of accurate beam shape and flat-top intensity allows uniform LIPSS production in a region of ~0.4mm along optical axis, which is well over the Rayleigh length. Benefits and limitations and of this technique are also discussed.