Interaction of electromagnetic pulses and nanostructures

Vanderbilt University, Nashville TN

Investigators

Abstract

NONTECHNICAL SUMMARY This award supports computational research aimed at developing and applying new methods to model the interaction of electromagnetic waves and matter. Almost everything in everyday life around us, from photosynthesis to television screens and mobile phones, is a result of some form of interaction of electromagnetic fields (light) and matter. Atoms and molecules in matter can absorb and emit light and can interact with each other coupled to electromagnetic fields. When electromagnetic fields are weak, their interaction changes the dynamics of electrons and nuclei, but the electromagnetic fields themselves remain unperturbed. When strong electromagnetic fields interact with matter, however, the motion of the electrons and the nuclei induce electromagnetic fields in addition to the incident fields. The induced fields can be substantially larger than the incident field and this can significantly change the material properties. The goal of this project is to simulate the interaction of coupled light-matter systems by using a quantum description of the matter and classical field approach to the electromagnetic fields in a self-consistent, coupled formalism. The developed methods will be applied to a wide range of nanomaterials that are of fundamental and technological importance. This award will also provide broad research training opportunities for graduate, undergraduate, and high school students in an interdisciplinary environment overarching physics, electrical engineering, materials science, quantum mechanical simulations, high-performance computing, and novel computational algorithms. In addition, the PI will host high-school teachers through the Vanderbilt Research Experiences for Teachers program, and develop classroom modules with them on emerging scientific and technological frontiers in nanoscience and computational modeling. TECHNICAL SUMMARY This award supports computational research aimed at developing and applying a time-dependent orbital-free (TD-OF) approach coupled with Maxwell equations to describe the interaction of electromagnetic waves and matter. The coupled Maxwell TD-OF equations treat the electron and photon dynamics in a microscopic framework on equal footing. In the coupled frame, the densities and currents are calculated using a quantum mechanical approach in the presence of a time-dependent vector potential, and then Maxwell equations are solved using the quantum mechanically calculated time-dependent microscopic currents and densities. A new approach, the Riemann-Silberstein formalism, will be used to solve Maxwell equations by the propagation of "the wave function of the photon". The OF approach will allow for electrodynamic simulations to be performed for systems of experimentally relevant sizes with a quantum description of the electrons. The results of the simulations will be tested against recent experimental results. Computational challenges of gap plasmonics (charge transfer plasmons, plasmonic tunnel junctions, high harmonic generation) and 2D plasmonics (real space mapping, edge plasmons, terahertz plasmonics) will be pursued. This award will also provide broad research training opportunities for graduate, undergraduate, and high school students in an interdisciplinary environment overarching physics, electrical engineering, materials science, quantum mechanical simulations, high-performance computing, and novel computational algorithms. In addition, the PI will host high-school teachers through the Vanderbilt Research Experiences for Teachers program, and develop classroom modules with them on emerging scientific and technological frontiers in nanoscience and computational modeling. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.