Sensitivities Of Large-Aperture Plasmonic Metasurface Flat Lenses In The Long-Wave Infrared

Plasmonic metasurface lenses based on polarization conversion are inherently limited in efficiency, and as a result, they have been given sparse attention in favor of higher-performing dielectric variants. However, recent proposals for expanding the design beyond a single interface offer hope for efficient plasmonic structures. Before developing these multi-layer structures, we wish to better understand dependencies of 2D plasmonic designs. Here we demonstrate the spectral, polarization and geometrical sensitivities of nine large-scale variants of the original V-antenna lens design at lambda(0) = 8 mu m. We show that the spectral response oscillates rapidly within a span as small as lambda(0)/320, and that strong focusing can occur at both the designed polarization state, and its orthogonal state-and with differing focal distances. Additionally, we determine that the lens performance is only weakly tied to the size of the discretization, offering only marginal improvement as the discretization approaches a continuum.