Theoretical and Numerical investigations of fused silica modification using ultrafast double-pulses

Qing Liu, Jianjun Wang, Guanghua Cheng, Junjun Chen, Feifei Liu, Changqing Liu

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

We study the mechanisms of ultrafast free-electron generation in laser-irradiated dielectrics (fused silica). The evolution of the free-electron density in the conduction band of dielectrics irradiated by ultrafast double-pulses laser is calculated. The effects of the avalanche ionization is calculated with the recently introduced multiple rate equation, which keeps track of the energy distribution of the free electrons, while maintaining the conceptual and analytic simplicity of the standard rate equation. Using temporally shaped pulse trains with picosecond separation leads to a significant improvement in the quality of ultrafast laser micro-structuring of dielectrics. The evolution of the free-electron density in fused silica irradiated by tightly focused 100 fs laser double-pulses at a center wavelength of 800 nm are numerically investigated to study the role of nonlinear photo-ionization and avalanche ionization processes in free electron generation. The role of impact ionization as compared to photoionization is analyzed.

Original languageEnglish
Title of host publication27th International Congress on High-Speed Photography and Photonics
DOIs
StatePublished - 2007
Externally publishedYes
Event27th International Congress on High-Speed Photography and Photonics - Xi'an, China
Duration: 17 Sep 200622 Sep 2006

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume6279 PART 2
ISSN (Print)0277-786X

Conference

Conference27th International Congress on High-Speed Photography and Photonics
Country/TerritoryChina
CityXi'an
Period17/09/0622/09/06

Keywords

  • Ablation mechanism
  • Double-pulses laser
  • Electron number density
  • Femtosecond laser

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