Keeping dark modes dark: Reducing the effects of symmetry breaking at oblique incidence

Abstract

Dark modes are defined by their lack of radiative coupling to the far field. However, the modes can be made to couple to far field radiation by symmetry breaking. For a resonant dimer, obliquely incident waves can create a phase difference in the currents between the elements, resulting in symmetry breaking. This work reduces symmetry breaking effects by minimizing the size of a dimer of dipolar elements with respect to its resonant wavelength. We obtain a mode that can experimentally be excited from the near field but has negligible excitation in the far field for obliquely incident waves. Such a mode could have use in wireless security applications.