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The electrically tunable properties of liquid-crystal fishnet metamaterials are theoretically investigated in the terahertz spectrum. A nematic liquid crystal layer is introduced between two fishnet metallic structures, forming a voltage-controlled metamaterial cavity. Tuning of the nematic molecular orientation is shown to shift the magnetic resonance frequency of the metamaterial and its overall electromagnetic response. A shift higher than 150 GHz is predicted for common dielectric and liquid crystalline materials used in terahertz technology and for low applied voltage values. Owing to the few micron-thick liquid crystal cell, the response speed of the tunable metamaterial is calculated as orders of magnitude faster than in demonstrated liquid-crystal based non-resonant terahertz components. Such tunable metamaterial elements are proposed for the advanced control of electromagnetic wave propagation in terahertz applications.Metamaterials (MM) are artificial structures characterized by features on a sub-wavelength scale, which exhibit fascinating properties not found in their natural counterparts. By proper design, for instance, one can engineer their permittivity and permeability values, which can lead to negative refractive index and associated physical phenomena, eg negative refraction, antiparallel phase velocity, or subwavelength focusing 1. Owing to such exotic possibilites, they are envisaged as the core element in a broad range of applications spanning from beam steering and lenses 2, electromagnetic (EM) wave modulators and absorbers 3, to chemical and bio-sensors 4 or electromagnetic cloaking techniques 5, 6. Since the first …
Nature Publishing Group
Publication date: 
1 Jan 2015

Romeo Beccherelli, Dimitrios C Zografopoulos

Biblio References: 
Volume: 5 Issue: 1
Sci. Rep.