Quantitative Extraction of Equivalent Lumped Circuit Elements for Complex Plasmonic Nanostructures

We establish a general method to
bridge the gap between full-field
electromagnetic calculations and equivalent lumped circuit elements
to describe the optical response of plasmonic nanostructures. The
exact value of each lumped element is extracted from one single full-field
calculation using the Poynting vector and considerations on the energy
flow in the system. The equivalent circuit obtained this way describes
the complete response of the system at any frequency and can be used
to optimize it for specific applications or perform parametric studies.
This powerful approach can accurately reproduce the behavior of complex
plasmonic nanostructures, such as Fano resonances, retardation effects,
and polarization coupling. Furthermore, the influence of coupling
parameters within the different modes supported by a given plasmonic
structure can be investigated, thus providing new physical insights
into its functioning mechanisms.