Freiburg 2024 – scientific programme
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A: Fachverband Atomphysik
A 6: Atomic Systems in External Fields I
A 6.7: Talk
Monday, March 11, 2024, 18:30–18:45, HS 1098
Ab Initio Dynamics of Orbital Angular Momentum Transfer to Atomistic Systems — •Esra Ilke Albar1, Franco P. Bonafé1, Valeriia Kosheleva1, Heiko Appel1, and Angel Rubio1,2,3 — 1Max Planck Institute for the Structure and Dynamics of Matter — 2Center for Computational Quantum Physics (CCQ), The Flatiron Institute, 162 Fifth Avenue, New York, NY, 10010, USA — 3Nano-Bio Spectroscopy Group, Departamento de Física de Materiales, Universidad del País Vasco, 20018, San Sebastian, Spain
Optical vortices are characterized by their orbital angular momentum (OAM) content. Due to their structured wavefront they can induce transitions beyond the dipole approximation. The study of their interaction with atomic and molecular systems in real time, therefore, demand novel computational tools that consider the spatial profile of the incoming fields.
We perform numerical simulations within the time-dependent density functional theory (TDDFT) using the Octopus code, coupling the time-dependent Kohn-Sham equations with Maxwell's equations, to describe self-consistent light and matter dynamics. We account for the spatial structure of optical vortices at different coupling levels beyond dipole using the multipolar expansion as well as the full minimal coupling Hamiltonian. We use atoms as a benchmark system and analyze the validity of the selection rules for different multipolar terms, considering incoming Bessel beams of different order and handedness. We also investigate the effect of other optical vortex parameters on the interaction such as the impact parameter and the envelope function.
Keywords: orbital angular momentum; optical vortex; twisted light; TDDFT; ab initio numerical simulations