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The spectroscopy study of focused short-wavelength laser-matter interactions
Burian, Tomáš ; Juha, Libor (advisor) ; Čuba, Václav (referee) ; Klír, Daniel (referee)
Title: The spectroscopy study of focused short-wavelength laser-matter interactions Author: Tomas Burian Department: Department of Surface and Plasma Science Supervisor: Ing. Libor Juha, CSc., Department of Radiation and Chemical Physics, Institute of Physics of the Czech Academy of Sciences, Prague Abstract: This thesis is focused on processes occurring during and immediately after an interaction of intense short-wavelength laser pulses with matter. Extreme states of matter (warm dense matter - WDM and hot dense matter - HDM), induced by EUV/SXR/X-ray lasers of two kinds, i.e., free-electron lasers (FEL) and plasma-based lasers, were investigated by emission spectroscopy over various spectral ranges and mass spectroscopic techniques. Absorption/transmission experiments revealed an effect of saturable absorption of soft X-ray laser radiation in aluminium WDM. Then, an ionisation potential depression (IPD) in dense plasmas was investigated by means of X-ray emission spectroscopy. Results obtained with the X-ray FEL-produced plasma exhibit very good agreement with computer simulations considering the Ecker-Kröll model. Analysis of optical emission spectra (OES) supports the key role played by fast recombination processes in the ablation plume created by focused short-wavelength laser beams on the solid target...
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Material properties of lithium fluoride for predicting XUV laser ablation rate and threshold fluence
Blejchař, T. ; Nevrlý, V. ; Vašinek, M. ; Dostál, Michal ; Pečínka, L. ; Dlabka, J. ; Stachoň, M. ; Juha, Libor ; Bitala, P. ; Zelinger, Zdeněk ; Pira, P. ; Wild, J.
This paper deals with prediction of extreme ultraviolet (XUV) laser ablation of lithium fluoride at nanosecond timescales. Material properties of lithium fluoride were determined based on bibliographic survey. These data are necessary for theoretical estimation of surface removal rate in relevance to XUV laser desorption/ablation process. Parameters of XUV radiation pulses generated by the Prague capillary-discharge laser (CDL) desktop system were assumed in this context. Prediction of ablation curve and threshold laser fluence for lithium fluoride was performed employing XUV-ABLATOR code. Quasi-random sampling approach was used for evaluating its predictive capabilities in the means of variance and stability of model outputs in expected range of uncertainties. These results were compared to experimental data observed previously.
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