Femtosecond laser-induced cross-periodic structures on a crystalline silicon surface under low pulse number irradiation

Xu Ji, Lan Jiang, Xiaowei Li, Weina Han, Yang Liu, Andong Wang, Yongfeng Lu

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

A cross-patterned surface periodic structure in femtosecond laser processing of crystalline silicon was revealed under a relatively low shots (4 < N < 10) with the pulse energy slightly higher than the ablation threshold. The experimental results indicated that the cross-pattern was composed of mutually orthogonal periodic structures (ripples). Ripples with a direction perpendicular to laser polarization (R ) spread in the whole laser-modified region, with the periodicity around 780 nm which was close to the central wavelength of the laser. Other ripples with a direction parallel to laser polarization (R ) were found to be distributed between two of the adjacent ripples R , with a periodicity about the sub-wavelength of the irradiated laser, 390 nm. The geometrical morphology of two mutually orthogonal ripples under static femtosecond laser irradiation could be continuously rotated as the polarization directions changed, but the periodicity remained almost unchanged. The underlying physical mechanism was revealed by numerical simulations based on the finite element method. It was found that the incubation effect with multiple shots, together with the redistributed electric field after initial ablation, plays a crucial role in the generation of the cross-patterned periodic surface structures.

Original languageEnglish (US)
Pages (from-to)216-221
Number of pages6
JournalApplied Surface Science
Volume326
DOIs
StatePublished - Jan 30 2015

Keywords

  • Cross-periodic surface structure
  • Femtosecond laser
  • Polarization
  • Silicon

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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