The Fano Resonance in Symmetry Broken Terahertz Metamaterials

The spectral characteristic of a Fano resonance is a distinct and unique asymmetric line shape. It arises from the destructive interference between a bright continuum mode and a discrete dark mode. Metamaterials and plasmonics have facilitated the observation of Fano resonances in the realm of classical electrodynamics and have spurred intense interest to study and to exploit their peculiarities due their low loss and very sharp resonant features. Here, we survey the excitation of Fano resonance at terahertz frequencies by using asymmetric metamaterial structures. In particular, we discuss the high Q of Fano resonances, their sensitivity to the asymmetry parameter and potential applications. We believe that the manipulation of terahertz radiation by exploiting Fano resonances in terahertz metamaterials could usher in next-generation terahertz photonic devices for delay, storage, filtering, sensing, and nonlinear applications.