Berlin 2024 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 61: Liquid and Amorphous Materials III

MM 61.1: Vortrag

Donnerstag, 21. März 2024, 15:30–15:45, C 243

Spectroscopic imaging pump-probe ellipsometry on fused silica after femtosecond laser irradiation — •Theo Pflug, Markus Olbrich, and Alexander Horn — Laserinstitut Hochschule Mittweida, 09648 Mittweida, Germany

Focused ultrashort-pulsed laser radiation enables the processing of transparent dielectrics such as glass even if the photon energy is lower than the energy band gap of the material. The underlying nonlinear physical processes, namely multiphoton-, tunnel-, and avalanche-ionization, have already been investigated in numerous experimental and theoretical studies and depend strongly on the transient optical properties of the material during irradiation. In this paper, we present a pump-probe setup combined with an imaging ellipsometer that allows to measure the transient complex refractive index of the excited material with a temporal, spectroscopic, and spatial resolution. The comparison of the measured transient optical properties of fused silica with various theoretical models for describing the dielectric function from the literature allows the validation of these models, and therefore a better insight into nonlinear excitation processes.

Keywords: Spectroscopic Imaging Pump-Probe Ellipsometry; Femtosecond Laser Radiation; Fused Silica; Lorentz-Drude Model