Naslov
Laser Induced Nonlinear Processes: Pathway to the New Technology

Autori
Lugomer, Stjepan

Izvornik
Http://www.math.kyushu-u.ac.jp/calendar/seminar_view.php?B_Code=1088

Vrsta, podvrsta
Ostale vrste radova, ostalo

Godina
2009

Ključne riječi
laser-matter interactions ; nonlinear processes ; sponge-like metals ; silicon recondenstaion ; silicon surface nanostructring
(aser-matter interactions ; nonlinear processes ; sponge-like metals ; silicon recondensation ; silicon surface nanostructring)

Sažetak
The ultrafast phenomena induced by nanosecond laser pulses cause the target surface modifica- tion, micro- and nano-structuring, originating from nonequilibrium and nonlinear dynamics of a vapor/liquid layer. The experiments performed in the semiconfined configuration induce in the vapor/liquid layer the phenomena like, superhea- ting, acceleration, recondensation, etc., which are important from the fundamental and from the applied aspect, of the "Science for Industry" research projects. Superheating of the high melting /boiling point metals: Surface structuring by micro-porosity ; the catastrophic phase transition of superhea- ted metals and phase explosion - generate the surface metal foam and sponge. Surface structu- ring by nano-porosity ; The solitary-like loca- lized vapor/plasma oscillations generate regular and irregular 1D and 2D arrays of nanoholes. The irregular arrays are consistent with the result of numerical simulation based on the 4-th order partial dif.Benney equation ; the 1D and 2D regular ones are consistent with simulation ba- sed on Boussinesq, and Kadomtsev-Petviashvili eq., respectively. Acceleration of surface melted layer of low melting/boiling point metals: Surface structuring by vortex micro-filaments ; The acceleration of melted layer ; Formation of vortex filaments, their instability, filament-filament interactions, and the interaction of filaments with point de- fects, resulting in: the filament looping, Hopf-linke chains, Voronoi cells, and the accumulation of filaments on vortex rings. Recondensation of silicon vapor: Surface nanostructuring of a silicon wafer ; A quasi-2D turbulent Si-vapor-field evolves into point vortices which condense into nanodroplets and solidify into low density, and high density Si nanoparticle patterns (at the end of the laser pulse).The condensation of Si point vortices in a thin Si-vapor-layer is represented by numerical simulations based on 2 D nonlinear Schrodinger equation. フ ァ イ ル

Izvorni jezik
Engleski

Znanstvena područja
Fizika

Napomena
Predavanje je objavljeno na web adresi Kyushu Univerziteta-Center "Mathematics for Industry" na japanskom i engleskom jeziku.

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