Dynamic wavefront and polarisation control for ultrashort-pulse laser microprocessing

New developments in wavefront and polarisation control for ultrashort-pulse laser microprocessing are presented. Two Spatial Light Modulators are used in combination to structure the optical fields of a picosecond-pulse laser beam, producing vortex wavefronts and radial or azimuthal polarisation states. Demonstration of multiple first-order beams with vortex wavefronts and radial or azimuthal polarization states is given, produced using Computer Generated Holograms. The beams produced are used to nano-structure a highly polished metal surface. Laser Induced Periodic Surface Structures are observed and used to directly verify the state of polarisation in the focal plane and help to characterize the optical properties of the setup. © 2014 The Authors. Published by Bayerisches Laserzentrum GmbH