Fano resonances in THz metamaterials composed of continuous metallic wires and split ring resonators

Abstract

We demonstrate theoretically and experimentally that Fano resonances can be obtained in terahertz metamaterials that are composed of periodic continuous metallic wires dressed with periodic split ring resonators. An asymmetric Fano lineshape has been found in a narrow frequency range of the transmission curve. By using a transmission line combined with lumped element model, we are able to not only fit the transmission spectra of Fano resonance which is attributed to the coupling and interference between the transmission continuum of continuous metallic wires and the bright resonant mode of split ring resonators, but also reveal the capacitance change of the split ring resonators induced frequency shift of the Fano resonance. Therefore, the proposed theoretical model shows more capabilities than conventional coupled oscillator model in the design of Fano structures. The effective parameters of group refractive index of the Fano structure are retrieved, and a large group index more than 800 is obtained at the Fano resonance, which could be used for slow light devices.

Free-Standing Complementary Asymmetric Metasurface for Terahertz Sensing Applications

“…This can be mitigated by designing the metallic structure of metasurfaces such that it exhibits a sharp asymmetric resonance, which is known as Fano resonance [39][40][41]. Split-ring resonators show Fano resonances if their structural symmetry is broken [42][43][44]. This resonance can be spectrally sharp and can reach high quality factors.…”

Terahertz polarization sensing based on metasurface microsensor display anti-proliferation of tumor cells with aspirin

“…As a class of artificial composite materials arranged at subwavelength structures, MMs own extraordinary electromagnetic response that would not be possible with natural materials [11]. By virtue of superior properties of metamaterials, an increasing number of THz metamaterials have been synthesized and applied to the management of THz signals in biomedical research [14][15][16][17][18][19][20][21][22][23][24][25]. The advantages of the MMs-based biosensors open up a door for the cell detection into low cost, label-free and fast process, being promising method in future biological sensing and disease diagnosis.…”

Tunable nanoplasmonic sensor based on the asymmetric degree of Fano resonance in MDM waveguide

“…Large amount of researches have been devoted to generating the Fano resonances and studied the related sensing properties in various plasmonic structures 6 7 8 9 10 , such as nanoparticle clusters 6 , metamaterials 7 , and non-concentric cavity 8 in the past several years. As another special property of the Fano resonance, the light speed in a Fano system can be significantly slowed down due to the steep phase dispersion 11 12 , which can enhance the light intensity by reason of the pulse compression. This unique characteristic can improve the sensing due to the increased light-mater interaction 13 .…”