ÖPG-CMD Joint Meeting 2026

Bridging quantum to Classical Optics with Feibelman Parameters: from TDDFT to Mesoscopic Maxwell Solvers for Plasmonics

Sep 22, 2026, 11:15 AM

15m

HS 15.05 (University of Graz)

3) Contributed talk M17 - Emerging trends in dielectric nanophotonics Mini-Colloquium

Speaker

Lorenz Huber (University of Graz, Insitute of Physics, Graz, Austria)

Description

Plasmonics enables light confinement at the nanoscale, leading to strong field enhancements (1). When dealing with sharp particle features, gaps, or field variations on the nanometer scale, quantum surface effects become significant. Conventional Maxwell descriptions of these systems can lead to inaccurate results under such extreme situations.

Recently, it has been suggested to account for quantum surface effects through mesoscopic boundary conditions (2) that incorporate frequency-dependent dispersive and/or nonlocal Feibelman parameters (3, 4). The theoretical and numerical foundations of this mesoscopic approach have advanced significantly over the past decade (2,5,6), and proved to describe the important quantum effects with sufficient accuracy, in comparisons to results from supplementary time-dependent density functional theory simulations (4). However, the availability of accurate and nonlocal Feibelman parameters, particularly for plasmonic materials like gold and silver, and their dispersive behavior, remains limited.

In this work, we present a consistent methodology to derive dispersive Feibelman parameters for gold-dielectric interfaces, starting from either ab-initio time-dependent density functional theory (TDDFT) or computationally cheaper self-consistent hydrodynamic models (7). The extracted parameters are then translated into the mesoscopic regime through modified boundary conditions, enabling their use in real-space analytical and numerical Maxwell solvers. We demonstrate the power of this approach by combining macroscopic structural effects with microscopic quantum corrections. Specifically, we accurately model realistic plasmonic systems, like nanoantennas and nanoresonators, by placing nanoparticles on stratified dielectric media while directly accounting for interfacial quantum effects. This hybrid framework, merging theoretical rigor with precomputed quantum mechanical information, enables fast and accurate simulations of optical resonances, which would be computationally prohibitive using pure TDDFT methods. Our approach paves the way for the design and tuning of plasmonic resonances in applications ranging from two-particle dimers to sub-nanometer meta-surfaces, bridging the gap between quantum and classical optics for next-generation nanophotonic devices.

References

1. U. Hohenester, “Nano and Quantum Optics”, Springer Cham, Switzerland (2020).
2. Y. Yang, D. Zhu, W. Yan, A. Agarwal, M. Zheng, J. D. Joannopoulos, P. Lalanne, T. Christensen, K. K. Berggren, and M. Soljacic, “A general theoretical and experimental framework for nanoscale electromagnetism”, Nature 576, 248 (2019).
3. P. J. Feibelman, “Surface electromagnetic fields”, Prog. Surface Science. 12, 287 (1982).
4. A. Babaze, T. Neuman, R. Esteban, J. Aizpurura, and A. G. Borisov, “Dispersive surface-response formalism to address nonlocality in extreme plasmonic field confinement”, Nanophotonics 12, 3277 (2023).
5. L. Huber and U. Hohenester, “A computational Maxwell solver for nonlocal Feibelman parameters on plasmonics”, J. Phys. Chem. C 129, 5 (2025).
6. U. Hohenester and G. Unger, “Nanoscale electromagnetism with the boundary element method”, Phys. Rev. B 105, 075428 (2022).
7. G. Toscano, J. Straubel, A. Kwiatkowski, C. Rockstuhl, F. Evers, H. Xu, N. A. Mortensen and M. Wubs, “Resonance shifts and spill-out effects in self-consistent hydrodynamic nanoplasmonics”, Nature Communications 6, 7132 (2015)