Surface Structuring

Weikert, Michael; Dausinger, Friedrich

doi:10.1007/978-3-540-39848-6_9

Cited by 7 publications

(2 citation statements)

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“…This is described byṅ pi in the MRE in equation Eq. (6). From there on electrons can absorb single photons with a rate W 1pt , thus gaining energy equivalent to one photon energy ω L , and can be excited from energy level ε n to energy level ε n+1 .…”

Section: Multiple Rate Equationmentioning

confidence: 99%

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Electron dynamics in transparent materials under high-intensity laser irradiation

Brenk

Rethfeld

2011

SPIE Proceedings

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The energy of a laser beam, irradiating a surface, is primarily absorbed by electrons within the solid. In actual transparent materials, absorption is low. High-intensity lasers may, however, be absorbed by initially bounded electrons through nonlinear processes. The increase of free electron density leads eventually to dielectric breakdown and the material becomes highly absorbing. We present theoretical studies on the dynamics of electrons in dielectrics under irradiation with a visible high-intensity laser pulse. We consider microscopic processes determining absorption, redistribution of the energy among electrons and transfer of energy to the crystal lattice. We review different aspects of electronic excitation, studied with time-resolved models as the Boltzmann kinetic approach and the time and spatial resolved multiple rate equation. Further we investigate criteria for damage thresholds. Two concepts compare, namely a critical free electron density and the melting threshold of the lattice. We show that in dielectrics both criteria are fulfilled simultaneously. Optical parameters depend on the density of free electrons in the conduction band of the solid, so the free electron density directly leads to an increased energy absorption causing material modification. We present results on the spatial dependence of dielectric breakdown.

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Section: Multiple Rate Equationmentioning

confidence: 99%

“…These laser pulses allow for ultraprecise micromachining and hole drilling even of transparent materials. [3][4][5][6] Applications are found in dentistry 7 and eye surgery. 8 Apart from these applications lasers have opened our eyes for fundamental physical processes on ultrashort, meaning femtosecond, timescales.…”

Section: Introductionmentioning

confidence: 99%