Tailored optical vector fields for ultrashort-pulse laser induced complex surface plasmon structuring

Abstract

Precise tailoring of optical vector beams is demonstrated, shaping their focal electric fields and used to create complex laser micro-patterning on a metal surface. A Spatial Light Modulator (SLM) and a micro-structured S-waveplate were integrated with a picosecond laser system and employed to structure the vector fields into radial and azimuthal polarizations with and without a vortex phase wavefront as well as superposition states. Imprinting Laser Induced Periodic Surface Structures (LIPSS) elucidates the detailed vector fields around the focal region. In addition to clear azimuthal and radial plasmon surface structures, unique, variable logarithmic spiral micro-structures with a pitch Λ ∼1μm, not observed previously, were imprinted on the surface, confirming unambiguously the complex 2D focal electric fields. We show clearly also how the Orbital Angular Momentum(OAM) associated with a helical wavefront induces rotation of vector fields along the optic axis of a focusing lens and confirmed by the observed surface micro-structures.

Laser ablation of silicon induced by a femtosecond optical vortex beam

“…This, in turn, suggests a deterministic relationship between orientation and characteristic size of the surface structure and local polarization and fluence of the OV beam. It is worth noting that earlier studies mainly focused on subwavelength ripples [1,2,8,9,[14][15][16]21], while more detailed analyses of microwrinkles produced by fs Gaussian beams started only very recently [24,25]. Our findings indicate that the two structures are ubiquitous to fs laser ablation of silicon.…”

“…Laser-induced structures and crater profiles have been used as a direct way to diagnose intense, cylindrical vector beams in the focal plane [13][14][15][19][20][21]. Actually, there is no research addressing the optimal conditions for the formation of the diverse surface structures produced during laser irradiation of a solid target with a fs OV beam.…”

Biomimetic surface structuring using cylindrical vector femtosecond laser beams

“…However, to date, laser fabrication of biomimetic structures has been demonstrated using laser beams with a Gaussian intensity spatial profile and spatially homogeneous linear polarization18. In this context and based on the sensitivity of laser induced structures on laser polarization, it is possible to further advance the complexity of the fabricated structures via utilizing laser beams with a spatially inhomogeneous state of polarization19202122. CV beams, exhibiting tangential polarization states, are prominent examples23242526272829.…”

Bio-Inspired Functional Surfaces Based on Laser-Induced Periodic Surface Structures

“…Some authors reported about direct fs-laser LIPSS-based surface structuring by using tailored optical vortex beams with different spatial distributions of the polarization state which are generated by means of q-plates [101], SLM [102] and SLM in combination with s-waveplates [103], respectively. It was shown, that the vortex beams facilitate to extend the fabrication of even more complex and unconventional surface structures.…”