Talk

Friday, November 15th, 2013

Speaker
George Tsibidis
Affiliation
IESL, FORTH, Greece
Title
Morphological changes on semiconductor surfaces after irradiation with ultrashort-pulsed lasers
Location
Department of Physics Bldg., Voutes, 3rd floor Seminar Room
Time
16:00
Language
English
Abstract

Femtosecond laser pulses provide unique possibilities for high-precision material processing. Understanding of the underlying physics and fundamental mechanisms that take place in materials irradiated by ultrashort laser pulses can facilitate optimization of experimental parameters in current applications and development of contemporary pulsed laser technologies.

The fundamentals of the physical mechanisms are employed to conduct a thorough investigation of ultrashort pulsed laser induced surface modification due to conditions that result in a superheated melted liquid layer and material evaporation are considered. The proposed theoretical model aims to address the laser-material interaction in sub-ablation conditions and thus minimal mass removal in combination with a hydrodynamics-based scenario of the crater creation and ripple formation following surface irradiation with single and multiple pulses, respectively. The development of the periodic structures is based on a synergy of electron excitation and capillary wave solidification and the interference of the incident wave with a surface plasmon wave.

A hybrid theoretical model is also presented to describe thermoplastic deformation effects on silicon surfaces induced by single and multiple ultrashort pulsed laser irradiation in submelting conditions.

Some early results of a similar mechanism is presented to describe thermal response of other types of materials (i.e. bimetallic layers) upon irradiation with ultrashort pulsed lasers.

See text.