Conductive Coupling of Split Ring Resonators: A Path to THz Metamaterials with Ultrasharp Resonances

Prof. Morandotti and his collaborators develop a novel metamaterial that sustains high quality factor, applicable over the entire electromagnetic spectrum.

Split Ring Resonance

Figure: Current distribution for (a) the dipole resonance for the SRRs structure at f 1 = 1.5 THz, (b) the dipole resonance for the JSRRs structure at f2 = 1.24 THz, and (c) the new esonance for the JSRRs structure at f3 = 0.617 THz.

In this work, Al Naib et Al report on a novel metamaterial structure that sustains extremely sharp resonances in the terahertz domain. This system involves two conductively coupled split ring resonators that together exhibit a novel resonance, in broad analogy to the antiphase mode of the so-called Huygens coupled pendulum. Even though this resonance is in principle forbidden in each individual symmetric split ring, our experiments show that this new coupled mode can sustain quality factors that are more than one order of magnitude larger than those of conventional split ring arrangements. Because of the universality of the metamaterial response, the design principle we present here can be applied across the entire electromagnetic spectrum and to various metamaterial resonators.