Study of extreme ultraviolet laser ablation for fusion applications

Extreme ultraviolet (EUV) compact laser sources have become more available in university size laboratories. This type of laser offers unique characteristics in ablation of materials and interesting types of laser-plasma interactions that are not present in optical lasers interactions with matter. Recently these type of compact EUV laser sources have been widely used in the semiconductors industry due to their diffraction limits into a nanometre range which allow higher transistor densities in integrated circuits. This thesis discusses different aspects of EUV light. A capillary discharge EUV source with a Ne-like argon gain medium contained in an aluminium oxide capillary tube was used for different experiments. The comparison of the ablation process with EUV and optical light was discussed. Aspects such as the ablation topography and the ablation profile depth as a function of fluence were studied using materials with different ablation lengths, such as: gold, aluminium, silicon and copper. The applications in novel analysis methods using these short wavelength sources have become relevant as the size of these have been reduced considerably. The use of an EUV laser source in a time-of-flight mass (TOF MS) spectrometer as ionisation sources is also studied and discussed. This EUV TOF MS device developed in The Colorado State University was used to ablate different materials and measure the ionisation states achieved with this laser source. A plasma expansion model was proposed to understand the plasma expansion of the plume created after the ablation and to calculate the temperatures reached in the materials after the laser interaction. Simulations of the absorption and refraction processes during the interaction of a laser beam with a plasma are presented to consider the possibility of the development of diagnostics tools for high density plasmas which require lasers with frequencies above the plasma cutoff frequency. A discussion of the advantages and disadvantages of EUV laser sources in comparison to traditional optical laser widely used in diagnostics techniques is also presented in this work.