Magnetic plasmon in coupled nanosandwich structure

Abstract

We investigate the magnetic resonant modes in the coupled nanosandwich (CSW) structure, which can be considered a metamolecule composed of two meta-atoms (nanosandwiches). The coupling between two nanosandwiches leads to two magnetic resonant modes, the split of the single magnetic resonant mode. Moreover, the coupling effect in a more complicated system that consists of two closely placed CSWs is studied, where four magnetic resonant modes with different phase relationships between meta-atoms are observed. It is shown that the interaction between CSWs leads to this secondary split of the magnetic resonant mode. We further consider a one-dimensional metacrystal formed by a chain of CSWs, and directly observe the magnetic plasmon (MP) bands through the Fourier transformation approach. Modifying both the thickness of the middle metal layer of CSWs and the spacing between CSWs, one can efficiently engineer the MP band, and even open a bandgap. Such a CSW chain can even work as a subwavelength waveguide, which may have potential applications in nano-optics and photonics.