Optimization of plasmonic metasurfaces: A homogenization-based design

This article deals with the optimization of resonant plasmonic metasurfaces through their surface-homogenized counterpart. The derivation of effective transition conditions that takes into account the spatially varying geometries is done using locally periodic surface homogenization. The resulting model reduces the numerical cost of simulating these metasurfaces, thus allowing to find their design using adjoint-based optimization methods. This new algorithm is presented in details, together with various numerical examples to asses its validity and compare its performance with the classical design based on local phase matching.