Modal approach improves insight into scattering of lossy anisotropic materials

With developments of metamaterials and metasurfaces, researchers are developing tools to understand the absorption and scattering properties of composite materials, which have promising applications in nanophotonics. In this vein, Kossowski et al. take an atypical approach to modeling lossy and anisotropic scatterers with the aim to describe their underlying physical processes.

Since the scattering from anisotropic geometries is difficult to interpret physically, the researchers use a modal method that decomposes the response of the material into multipolar resonances. Traditionally, modal analyses are based around frequency, but the authors focused on the resonances called eigenpermittivity modes. By extending the generalized normal mode expansion, the researchers were able to decompose the total response of an anisotropic resonator into the modes of the corresponding isotropic resonator.

“Modal decomposition based on eigenpermittivity modes for isotropic materials is not new, and it was shown to have great advantages,” said author Nicolas Kossowski. “The novelty of our method is the extension and application to the case of anisotropic materials.”

Their method can untangle the material and geometric contributions to scattering of any anisotropic resonator, as well as identify absorption and scattering resonances with different modes. The authors tested the model with a complex case of a long cylinder with concentric metallic and dielectric layers, showing it had the scattering response predicted by the model.

“I think our method opens new possibilities for people that are interested in having a physical description of the interaction of light with anisotropic materials nanoparticles,” said Kossowski. “It benefits from the advantages of modal decomposition, which are faster computationally and have strong insights of the physical behavior.”

Source: “Scattering by lossy anisotropic scatterers: A modal approach,” by N. Kossowski, Parry Y. Chen, Q. J. Wang, P. Genevet, and Yonatan Sivan, Journal of Applied Physics (2021). The article can be accessed at https://doi.org/10.1063/5.0039134 .

This paper is part of the Plasmonics: Enabling Functionalities with Novel Material Collection, learn more here .