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O: Fachverband Oberflächenphysik
O 7: Plasmonics and Nanooptics I
O 7.5: Talk
Monday, March 18, 2024, 11:30–11:45, MA 043
Determination of the transient absorbance during ultrafast laser-matter interaction by applying ultrafast imaging ellipsometry — •Markus Olbrich, Pflug Theo, Lungwitz Philipp, and Alexander Horn — Laserinstitut Hochschule Mittweida, Hochschule Mittweida, Technikumplatz 17, 09648 Mittweida
Applying ultrafast imaging metrology combined with modeling the ablation represents a promising way to comprehend the interaction of ultrafast laser radiation with matter fundamentally. Accurately simulating the absorption of the laser radiation is challenging due to the complexity of the needed models and the temperature- and density-dependencies of all included parameters. To solve this, determining the absorbed energy by ultrafast imaging ellipsometry neglects the necessity of using an optical model.
In this study, a 150 nm thick gold film, including an adhesive layer of 25 nm chromium on a glass substrate is irradiated by single-pulsed ultrafast laser radiation (pump radiation: pulse duration τH = 40 fs, wavelength λ = 800 nm, peak fluence H0 = 5.0 J/cm2). Ultrafast imaging ellipsometry reveals the complex refractive index at the probe wavelengths 700 nm and 900 nm within 10 ps post-pump irradiation. The complex refractive index for the pump radiation at λ = 800 nm is calculated by linear interpolation afterward. Subsequently, the absorbed energy of the pump radiation is derived and included in the model. The simulations incorporating the experimentally determined absorbed energy yield a much better fit to the experimental results than uncorrected simulations.
Keywords: Ultrafast Laser Radiation; Pump-Probe; Imaging Ellipsometry; Two-Temperature Model Hydrodynamics; Laser Matter Interaction