From Event: SPIE Nanoscience + Engineering, 2019
We have already successfully employed the Generalized Dispersion Material (GDM) technique to include optical dispersion of different materials in the multiphysics time domain methods implementing the GDM model with various Auxiliary Differential Equation (ADE) and Recursive Convolution (RC) schemes. So far, we have demonstrated that the approach works efficiently to model the optical dispersion of metals, and to characterize the multivariate tunable dispersion of graphene. In this paper, we apply the GDM model to two emerging fields in the time-domain computational photonics.
In the first part, we further extend the GDM model to the Bi-Anisotropic (BA) case, where a full BA material tensor comes from homogenization procedure in the frequency domain. Conventional BA homogenization is a powerful multiscale technique for rapid prototyping and optimization of metasurfaces. With a new extension, the BA-GDM model characterizes artificial dispersion obtained from the mathematical equivalence of physical effects and enables the multiscale modeling of metasurfaces in the time domain.
Part 2 deals with new use of the GDM model in temperature-dependent time-domain simulations of phase change materials (PCMs). Optical PCMs, such as GST/GSST, are of critical utility in applications including, e.g., programmable metasurfaces, and nonvolatile memory. Typically, dispersions of amorphous and crystalline phases of PCMs are fitted separately in the frequency domain with a combination of the Tauc-Lorentz and Gauss terms, while Bruggeman’s mixing rule describes the transition states. Significantly advancing the-state-of-the-art, our GDM characterization describes dependency on temperature and crystallization levels explicitly and enables full wave modeling of PCMs in the time domain.
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Ludmila J. Prokopeva, Vladimir Liberman, Jeffrey Chou, Christopher Roberts, Mikhail Shalaginov, Yifei Zhang, Juejun Hu, Zhaxylyk Kudyshev, and Alexander Kildishev, "Time domain modeling of bi-anisotropic media and phase change materials with generalized dispersion (Conference Presentation)," Proc. SPIE 11080, Metamaterials, Metadevices, and Metasystems 2019, 1108006 (Presented at SPIE Nanoscience + Engineering: August 11, 2019; Published: 9 September 2019); https://doi.org/10.1117/12.2529097.6083772390001.