We report on laser surface structuring of silicon using Ti:Sa femtosecond laser ablation with optical vortex beams. A q-plate is used to generate an optical vortex beam with femtosecond pulse duration through spin-to-orbital conversion of the angular momentum of light. The variation of the produced surface structures is investigated as a function of the number of pulses, N, at laser fluence slightly above the ablation threshold value. At low N (10), only surface corrugation of the irradiated, ring-shaped area is observed. This is followed by a progressive formation of regular ripples at larger N (100–500), which eventually transform in smaller columnar structures for N1000. Moreover, the central, non-ablated part is gradually decorated by nanoparticles produced during laser ablation, a process which eventually leads to the formation of a central turret of assembled nanoparticles. Our experimental findings suggest the importance of a feedback mechanism and a cumulative effect on the formation of ripples with interesting patterns not achievable by the more standard beams with a Gaussian intensity profile.

Femtosecond laser surface structuring of silicon using optical vortex beams generated by a q-plate / Kilyanamkandy, Anoop; Rubano, Andrea; R., Fittipaldi; X., Wang; D., Paparo; A., Vecchione; Marrucci, Lorenzo; Bruzzese, Riccardo; Amoruso, Salvatore. - In: APPLIED PHYSICS LETTERS. - ISSN 0003-6951. - 104:(2014), pp. 241604-1-241604-5. [10.1063/1.4884116]

Femtosecond laser surface structuring of silicon using optical vortex beams generated by a q-plate

KILYANAMKANDY, ANOOP;RUBANO, ANDREA;MARRUCCI, LORENZO;BRUZZESE, RICCARDO;AMORUSO, SALVATORE
2014

Abstract

We report on laser surface structuring of silicon using Ti:Sa femtosecond laser ablation with optical vortex beams. A q-plate is used to generate an optical vortex beam with femtosecond pulse duration through spin-to-orbital conversion of the angular momentum of light. The variation of the produced surface structures is investigated as a function of the number of pulses, N, at laser fluence slightly above the ablation threshold value. At low N (10), only surface corrugation of the irradiated, ring-shaped area is observed. This is followed by a progressive formation of regular ripples at larger N (100–500), which eventually transform in smaller columnar structures for N1000. Moreover, the central, non-ablated part is gradually decorated by nanoparticles produced during laser ablation, a process which eventually leads to the formation of a central turret of assembled nanoparticles. Our experimental findings suggest the importance of a feedback mechanism and a cumulative effect on the formation of ripples with interesting patterns not achievable by the more standard beams with a Gaussian intensity profile.
2014
Femtosecond laser surface structuring of silicon using optical vortex beams generated by a q-plate / Kilyanamkandy, Anoop; Rubano, Andrea; R., Fittipaldi; X., Wang; D., Paparo; A., Vecchione; Marrucci, Lorenzo; Bruzzese, Riccardo; Amoruso, Salvatore. - In: APPLIED PHYSICS LETTERS. - ISSN 0003-6951. - 104:(2014), pp. 241604-1-241604-5. [10.1063/1.4884116]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/582579
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