The evidence of the role of surface plasmon polaritons in formation of femtosecond highly-regular laser-induced periodic structures on Cr films

A. V. Dostovalov, T. J.Y. Derrien, F. Preucil, T. Mocek, V. P. Korolkov, S. A. Babin, N. M. Bulgakova

Research output: Contribution to journalConference articlepeer-review

2 Citations (Scopus)

Abstract

Cr films of controlled thickness deposited on glass substrates were irradiated by a high number of low-intensity femtosecond laser pulses below the Cr single-pulse damage threshold, producing periodic surface structures (LIPSS) of very high regularity via metal oxidation. To address the multiplicity of electromagnetic modes allowed for thin films, a rigorous numerical approach for modeling surface plasmon polaritons (SPP) in thin-film geometry has been developed. Three types of modes are predicted: the classical SPP with periodicities Λ ~ λ (λ Is laser wavelength) at air-film interface, and ? ~ ?/n at film-substrate interface (n is refractive index of substrate), and a propagation mode ? ~ ?/nCr where nCr is refractive index of film material. Experimentally observed LIPSS periods match well the predicted modes for the extreme cases, ? ~ ?/n at film thickness h = 30 nm and ? ~ ? At h = 200 nm, indicating respectively the dominance of SPP excited at the film-substrate interface and at the metal surface. For 30 nm < h < 200 nm, decreasing of the film thickness results in transition from the pure surface mode to its coupling with and finally domination of the electromagnetic wave excited at the film-substrate interface, providing evidence of the SPP mechanism of LIPSS formation under laser irradiation of thin metallic films.

Original languageEnglish
Article number012025
JournalJournal of Physics: Conference Series
Volume1092
DOIs
Publication statusPublished - 1 Jan 2018
Event3rd International Conference on Metamaterials and Nanophotonics, METANANO 2018 - Sochi, Russian Federation
Duration: 17 Sep 201821 Sep 2018

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