Electron excitation effect on scattering near-field and far-field ablation material processing by femtosecond laser irradiation

Taira Enami, Go Obara, Mitsuhiro Terakawa, Minoru Obara

    Research output: Contribution to journalArticle

    1 Citation (Scopus)

    Abstract

    Femtosecond laser nano-processing by enhanced light scattered from nanospheres has received much attention. Enhanced scattered near field enables us to ablate nanoholes at nanometer scales below the diffraction limit. In addition, the interference between the scattered far field and the irradiated laser enables us to fabricate spatially controlled periodic surface structures. In this paper, we simulated the time evolution of scattered near field and far field during the free electron excitation in silicon (Si) by femtosecond laser irradiation. The optical property of Si changes from dielectric to metal-like Si due to the increase of the free electron number density excited by femtosecond laser pulse. It is elucidated that the scattered field of Si shifts from Mie scattering to plasmonic scattering during laser irradiation. We achieved the optimal free electron density and laser intensity for precisely controlled periodic surface structures fabrication. We explained the temporal behavior of the scattering near field and far field from the standpoint of dielectric function of the materials.

    Original languageEnglish
    Pages (from-to)253-259
    Number of pages7
    JournalApplied Physics A: Materials Science and Processing
    Volume114
    Issue number1
    DOIs
    Publication statusPublished - 2014 Jan 1

    ASJC Scopus subject areas

    • Chemistry(all)
    • Materials Science(all)

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