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Ultra-high refractive index in deep subwavelength coupled bi-layer free-standing flexible metamaterials

Ultra-high refractive index in deep subwavelength coupled bi-layer free-standing flexible metamaterials

Leena Singh

Electrical & Computer Engineering

IN A SENSE, every material is a composite, even if the individual ingredients consist of atoms and molecules.[1] These natural atoms when replaced with artificially designed unit cell structures (meta-atoms), result in an engineered material that is now well known as metamaterials. Metamaterial properties are derived from their meta-atoms rather than their composition. These sub-wavelength meta-atoms can be designed with unique shapes and sizes, and wit-fully arranged and oriented to achieve unconventional values of permeability[2] and permittivity[3], the characteristic electromagnetic properties of any material medium. By tailoring the electric and magnetic response of the material towards incident electromagnetic waves, the effective refractive index can be varied from negative[4-8] to zero[9-12], or even to higher positive values[13-19]. Metamaterials have created a completely new dimension to engineered materials. This has offered an opportunity to build new devices with exotic functionalities.[20] Metamaterials are proven to be especially valuable in the terahertz regime, where most naturally existing materials exhibit weak electromagnetic wave response.[21]

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