Limiting amplitude principle and resonances in plasmonic structures with corners: Numerical investigation

The limiting amplitude principle states that the response of a scatterer to harmonic light excitation is asymptotically with same pulsation. Depending on geometry and nature scatterer, there might or not be an established theoretical proof validating this principle. In paper, we investigate case where theory missing: consider two-dimensional dispersive Drude structure corners. non lossy case, it well known looking for solutions leads ill-posed problem specific range critical pulsations, characterized by metal’s properties aperture Ill-posedness then due highly oscillatory resonances at corners called black-hole waves. However, time-domain formulation always mathematically valid. Based observation, conjecture hold all pulsations. Using setting, propose systematic numerical approach allows give evidences latter conjecture, find clear signature Furthermore, connect our results underlying physical plasmonic occur in metallic case.