Theory for heating of metals assisted by surface plasmon polaritons

• Published in: Applied surface science Vol. 569; p. 150427
• Main Authors: Benhayoun, O., Terekhin, P.N., Ivanov, D.S., Rethfeld, B., Garcia, M.E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-12-2021
• Subjects: Hydrodynamic model; LIPSS; Surface Plasmon Polaritons; TTM; Ultrashort laser pulses; Hydrodynamic model; LIPSS; TTM; Ultrashort laser pulses; Surface Plasmon Polaritons
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2021.150427

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•A TTM + P continuum model has been derived, accounting for plasmons within a Two-Temperature description.•Plasmon fields are deduced from the linearized hydrodynamic model for free electrons.•The strength of excitation of the plasmon fields is highly dependent on the angle of incidence of the laser pulse.•Interference between laser and plasmon fields leads to a spatially modulated lattice temperature distribution.•Such temperature modulation may contribute to LIPSS formation.•The model can be adjusted to account for interband transitions at short wavelengths as well.
We propose a model accounting for plasmons within a two temperature description, to investigate the role of surface plasmon polaritons (SPP) in the energy redistribution between laser excited electrons and the lattice, leading to surface restructuring of the material. This energy transfer can lead to the creation of laser induced surface structures in metals illuminated by an ultrashort laser pulse. The Two Temperature Model+Plasmon (TTM + P) equations are constructed by applying perturbation theory on the energy-, momentum- and density conservation equations of free electrons in metals. We consider three subsystems: the lattice, the thermalized electrons and the SPP, subject to an external laser field irradiation. The interference between the laser and SPP fields leads to spatially modulated energy absorption by the electronic system, and, through electron–phonon collisions, periodically shapes the lattice temperature. A numerical analysis is performed on a 1D model for gold. We show the emergence of a periodic modulation of the lattice temperature, which may contribute to laser-induced periodic surface structures (LIPSS).