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Theory and Simulation


The theory and simulation activities of the 4th Physics Institute are guided by the junior research group Physical Optics, which supports the experimental work at the institute. This strong collaboration ensures a mutual exchange between theory and experiment on each step of the analysis and enables us to verify theoretical models and to prove the developed predictions. Our theoretical research activities include topics such as chiral and non-reciprocal plasmonics, hybrid quantum and nanophotonic systems, and photonic crystal fibers, with a strong emphasis on development of semi-analytical models and advanced numerical methods.


The optical properties of micro- and nanoobjects can be significantly modified by changing the shape and the spatial configuration of the nanoobjects. We can therefore design artificial systems with specific optical properties when understanding the underlying physical phenomena. This requires either semi-analytical or numerical solutions of Maxwell’s equations for various types of linear and non-linear materials. Especially metallo-dielectric systems turn out to be of great importance due to the occurrence of plasmonic resonances, i.e., collective oscillations of electrons in the metal. Potential applications are optical sensors, thin-film optical elements such as Faraday isolators and perfect absorbers, as well as integrated photonic circuits.

Adaptive coordinates


Our theoretical work relies on commercial software such as finite difference time domain software and finite element methods, as well as semi-analytical approaches and own numerical codes. Regarding the latter, we have implemented an advanced scattering matrix approach for periodic nanostructures based on the Fourier modal method with adaptive coordinates. Our implementation significantly improves the convergence of the method, so that we are able to calculate metallo-dielectric systems as well as chiral and non-reciprocal materials efficiently. Our code provides accurate results for far-field spectra, emitter calculations, near-field distributions, optical resonances, and density of states calculations and is permanently improved by state of the art extensions in order to cope with the research activities at the 4th Physics Institute.

Further Information

  • Matched coordinates and adaptive spatial resolution in the Fourier modal method
    T. Weiss, G. Granet, N. A. Gippius, S. G. Tikhodeev, and H. Giessen
    Optics Express 17, 8051 (2009).
  • Derivation of plasmonic resonances in the Fourier modal method with adaptive spatial resolution and matched coordinates
    T. Weiss, N. A. Gippius, S. G. Tikhodeev, G. Granet, and H. Giessen
    J. Opt. Soc. Am. A 28, 238 (2011).
  • Strong resonant mode coupling of Fabry-Perot and grating resonances in stacked two-layer systems
    T. Weiss, N. A. Gippius, G. Granet, S. G. Tikhodeev, R. Taubert, L. Fu, H. Schweizer, and H. Giessen
    Photonic. Nanostruct. 9, 390 (2011).