Real Space Perspective on High Harmonic Generation in Solids

Abstract

High harmonic generation in solids is a burgeoning field that employs strong and ultrashort electric fields to explore electronic dynamics. While existing models have successfully explained generation mechanisms in solids, they have predominantly focused on momentum space. To enhance our comprehension of matter and facilitate the development of faster signal processing devices, this thesis introduces a position model utilizing Wannier states. Firstly, I meticulously define parameters, including the separation of interband and intraband currents in various electric field gauges. Secondly, I transform the existing models, formulated in a Bloch basis (momentum space), into a Wannier basis, unveiling dynamics in position space. Utilizing this model in a strong field approximation, I uncover novel paths contributing to interband harmonic spectra, incorporating a distinct position component. This leads to the development of a quantitatively predictive semiclassical model. Lastly, I present experimental works where a position space perspective is crucial to elucidate observed results, spanning from 2D materials to nanoantennas.