Dielectric metasurfaces are being pushed as flat, low-loss alternatives to conventional bulk optical components, with performance determined by carefully engineered resonances. A webinar centered on COMSOL Multiphysics will show how full-wave finite-element simulation, combined with semianalytical multipole decomposition, can be used not only to predict those resonances but also to identify their physical origin.
The first example revisits a single quadrumer meta-atom originally studied for its magnetic octupole response. When that element is arranged into a periodic crystalline silicon metasurface, the optical behavior changes into an anomalous absorption enhancement regime driven by two independent multipole mechanisms that coexist in the same structure.
The presentation then extends the approach to a gallium nitride metasurface, where the interplay of four different multipoles is used to shape reflection and transmission spectra. In that case, the design also involves manipulation of quasi-bound states in the continuum, or q-BICs, adding another degree of control over the spectral response.
Beyond the specific structures, the key message is that multipole-based simulation serves as a design strategy rather than only a diagnostic method. By linking numerical field solutions with analytical decomposition, the method turns complex resonance behavior into interpretable rules for tailoring absorption, reflection, and transmission in dielectric metasurfaces. The applications named include sensing, energy harvesting, and future optical device development.