Metamaterials are artificial structures, having extraordinary abilities to manipulate electromagnetic waves far beyond the limits of natural materials. Due to the technology of fabrication, planer metamaterials are greatly restricted by pure magnetic resonant modes induced by in-plane EM waves.
In this work, we numerically demonstrate vertical double-split ring resonators by finite-element method software (CST). Our samples were fabricated by metal stress-driven self-folding method, which is so called 4D printing. In the beginning, we define our patterns in two-dimensional with by electron beam lithography and deposit Ni/Au bilayer metal on silicon substrate. After etching out underlying substrate by ICP-RIE, released stress in metal will deform our 2D metal patterns into 3D metamaterials.
Comparing with single-split ring resonators, DSRRs are considered with more freedom to tailor resonance frequency by changing the length of arms and the distance between them. Here we investigated the effects of symmetry breaking and resonance mode hybridization at mid-infrared wavelength using coupled DSRRs. The proposed 3D metamaterials indicate some potential applications like modulators and filters in compact optical metadevices.
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