Polarization optical switching between supercell states of plasmonic metasurfaces

Abstract

We study, experimentally and numerically, in-plane light scattering (side scattering) and near- and far-field collective excitations in plasmonic metasurfaces consisting of periodic arrays of Au $\mathsf{V}$-shaped nanoantennas. Each unit cell in these arrays includes a pair of such nanoantennas facing each other ($<>$). We show that, depending on the polarization of the incident light, such metasurfaces can support two types of supercells ($<+>$ and $>+<$). $<+>$ is a braket supercell wherein two nanoantennas of the same unit cells are coupled to each other via their plasmonic fields. When the polarization of the incident light is rotated by ${90}^{\ensuremath{\circ}}$, a plasmonic conjugate supercell is formed ($>+<$). In this case the plasmon fields couple two $\mathsf{V}$-shaped nanoantennas of the neighboring cells, supporting a geometrical and near-field coupling process different from $<+>$. We show that braket and conjugate supercells support sharp infrared resonances at two different wavelengths, offering a high extinction polarization optical switching process associated with the transition between $<+>$ and $>+<$. Our results show that while $<+>$ supercells tend to be optically noninteracting with each other, $>+<$ supercells can get coupled to the lattice modes, spatially extending coherent properties across the arrays. We investigate the in-plane scattering of these arrays, demonstrating how variations of the charge configuration and phase by the incident light polarization can be used to coherently control the in-plane scattering of $\mathsf{V}$-shaped nanoantennas arrays.