Advances in Engineering Advances in Engineering features breaking research judged by Advances in Engineering advisory team to be of key importance in the Engineering field. Papers are selected from over 10,000 published each week from most peer reviewed journals.
Optics Express, Vol. 21, Issue 18, pp. 21198-21207 (2013).
O J Allegre, Y Jin, W Perrie, J Ouyang, E Fearon, S P Edwardson, and G Dearden.
Laser Group, School of Engineering, University of Liverpool, L69 3GQ, UK
Abstract
We report on new developments in wavefront and polarization control for ultrashort-pulse laser microprocessing. We use two Spatial Light Modulators in combination to structure the optical fields of a picosecond-pulse laser beam, producing vortex wavefronts and radial or azimuthal polarization states. We also carry out the first demonstration of multiple first-order beams with vortex wavefronts and radial or azimuthal polarization states, 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 polarization in the focal plane and help to characterize the optical properties of the setup.
© 2013 OSA
Additional Information:
The present article details some of the latest results obtained at the University of Liverpool’s Laser Group, where a new technique was developed to control both the wavefront and polarization of ultrashort-pulse laser beams. When applied to surface processing, the technique allows highly controlled micro/nano texturing of material surfaces, through controlled growth of the so called Laser Induced Periodic Surface Structures (LIPSS). For example, the Scanning Electron Microscope micrograph below shows LIPSS produced by ablating a highly polished steel surface near ablation threshold, with a radially polarized picosecond-pulse laser beam.
