Work package 1 dealt with light propagation and generation of new frequencies in composites and at solid-state surfaces. Collaboration between Germany, Belarus and Uzbekistan resulted in a novel numerical model and a modular code which includes multifarious relevant effects, such as excitons, photoionization, dynamic light localization, etc.
Several investigations combining Forward Maxwell equation, effective medium theory, time-dependent density-function theory, and multilevel description of electron structure of a nanoparticle (NP), were performed. Terahertz generation and short-pulse emission in composites as well as strong pulse reflection from a dielectric interface were investigated, with 3 publications and 2 code releases. Knowledge transfer between the mentioned participants is an important output of WP1 activity.
Work package 2 aimed at modelling of photo-excitation and combined electron phonon-photon dynamics for finite systems and solids. Notable achievements include the formulation of a QM/MM scheme with tight-binding approximation and of two novel computational approaches: coherent electron-electric field dynamics (CEED) and a set of kinetics equations based on Redfield formalism to model electron-photon interaction. The kinetic equations were also extended to include electron-phonon interactions. Both CEED and the kinetic equations and CEED were implemented in the open-source code LIO, while the QM/MM scheme and GPU parallelisation were implemented in the code Plato. Important links and knowledge transfer between the UK beneficiaries and the Argentinian partner institutions has also been achieved. Dissemination so far includes 2 published peer-reviewed articles.
Work Package 3 consisted in characterization of the electronic excitation in band-gap materials irradiated by ultrashort laser pulses. This WP took advantage of prediction capabilities of first-principle approaches for generating parameterizations to be employed in other types of theoretical descriptions of laser-matter interaction. This enabled substantial acceleration and simplification of numerical simulations, along with accounting for peculiar quantum aspects of the interaction for specific materials. Incorporation of microscopic inputs from TD-DFT calculations into macro-scale modelling provided new insights on the role of laser dressing on the absorption of energy, in a time- and space-resolved manner.
WP3 enabled secondments of researchers from Bulgaria, Czech Republic and France to Japan. During the secondments, seminars, workshops and daily discussions enabled training on a collection of simulation techniques, such as kinetic Boltzmann approaches, semiconductor Bloch equations, time-dependent density functional theory (TDDFT), and large-scale descriptions along with light propagation.
Work Package 4 consisted in training in modelling related to laser-induced relocation of materials. A numerical code has been implemented computing the evolution of species in a binary alloy upon pulsed laser irradiation, taking into account evaporation and interdiffusion of species. The code was successfully applied to the case of the irradiation of CdTe. Other relocation descriptions involving a coupling between thermal and fluid descriptions, have been considered. Preliminary numerical tools have been elaborated between Partners (BSU and NSU) and Czech Republic (IP-ASCR), to account for computation of laser-induced stress and motion of material irradiated by lasers. 3 ESR were trained and 1 proceeding published.
Work Package 5 consisted in training and research on plasmonic effects in laser-matter interaction using first-principles simulations and macroscopic descriptions. This WP aimed at improving knowledge in laser-matter interaction and transient optical properties of laser-irradiated solids in view of building better mathematical descriptions of energy absorption dynamics by laser-irradiated and nano-structured materials.
Fruitful exchange between Russia, Czech Republic and Argentina enabled mutual training of researchers in plasmonics of thin films and nanoparticles. In addition to daily interactions, invited seminars and international conferences were organised to enrich the dissemination of researchers activities within the project.
