title: Unidirectional broadband radiation of honeycomb plasmonic antenna array with broken symmetry.
abstract: Emerging plasmonic and photovoltaic applications benefit from effective interaction between optical antennas and unidirectional incident light over a wide spectrum. Here, we propose a honeycomb array of plasmonic nanoantennas with broken symmetry to obtain a unidirectional radiation pattern over a wide spectrum. The honeycomb nanoantenna array is based on a hexagonal grid with periodically arranged nanostructure building blocks. To analyze the far-field optical distribution and spectral behavior of the plasmonic antenna honeycomb, a two-dimensional Wigner-Seitz unit cell is used together with periodic boundary conditions. As a result of the vectoral superposition of the fields produced by the Wigner-Seitz unit cells, far-zone optical fields interfere constructively or destructively in different directions. The constructive interference along the array's normal direction engenders unidirectional radiation. Due to the broken symmetry of the Wigner-Seitz cell, multiple resonances are supported by the plasmonic antenna honeycomb array over a broad spectrum.
authors: Faculty of Engineering and Natural Sciences Sabancı University, Orhanlı - Tuzla, 34956 Istanbul, Turkey.
authors: Rüştü Umut
authors: RU
authors: Tok
authors: Cleva
authors: C
authors: Ow-Yang
authors: Kürşat
authors: K
authors: Sendur