Most modern optical / electronic devices operate in two distinct regimes of the electromagnetic spectrum. Electronic devices operate at frequencies of a few hundred gigahertz and lower where electrons are medium for EM propagation. Optical devices operate from infrared through optical/UV frequencies where photons are the medium. In-between these two fundamental response regimes there exists a region comparatively devoid of material response, commonly referred to as the “terahertz gap” (0.1 – 10THz, l = 3mm – 30mm). The development of artificially structured electromagnetic materials, termed metamaterials, has led to realization of electromagnetic properties in materials that cannot be obtained with natural materials. Metamaterials (MMs) are promising candidates to fill the “terahertz gap”. Metamaterials typically consist of structured composites with patterned metallic subwavelength inclusions. These mesoscopic systems are built from the bottom up, at the unit cell level, to yield specific electromagnetic properties. Individual components respond resonantly to the electric, magnetic or both components of the electromagnetic field. In this way electromagnetic MMs can be designed to yield a desired response at frequencies from the microwave through to the near visible.
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