Modeling linear and non-linear light-matter interactions: from classical to atomistic nanoplasmonics

Abstract

In the last years, nanoplasmonics has become an important research field in the realm of light-matterinteractions due to the wide range of applications. Driven by the interaction of electromagnetic radiationon nanostructures, resonant excitations of the so-called surface plasmons at the frequencies of electronicexcitations in matter, leads to an enhanced of the local electric field. Motivated by this phenomenon, inthis thesis, we have modeled different linear and non-linear interaction processes betweenelectromagnetic radiation and low-dimensional nanostructures to simulate particular physicalphenomena based on nanoplasmonics. Depending on the length scale of the system to be modeled, wehave used different techniques, ranging from classical to atomistic ab-initio methods. Specifically, wehave performed: (i) DDA and finite element method calculations to analyze the plasmonic behaviour ofrecently synthesized (by a collaborative research group) non-stoichiometric heavily-dopedsemiconductor nanocrystals (Cu2-xS, and WO3-x); (ii) fully atomistic ab-initio simulations on metalcluster dimers to analyze the anisotropy effects of the plasmonic response of this nanostructures,including the electric field enhancement and the photoinduced current, as well as the influence of a oneatomjunction between the two atomic conformations; (iii) and finally, motivated by a collaboration withanother experimental research group we have modeled laser ablation processes in low-dimensionalnanostructures, driven by intense and ultrashort laser pulses (in the plasmon resonance regime). Throughthese simulations, we have analyzed if Coulomb Explosion or electrostatic ablation is the mechanism ofmaterial removal in the early stage of the gentle ablation regime.