Metamaterial cloaking

Metamaterial cloaking is the usage of metamaterials in an invisibility cloak. This is accomplished by manipulating the paths traversed by light through a novel optical material. Metamaterials direct and control the propagation and transmission of specified parts of the light spectrum and demonstrate the potential to render an object seemingly . Metamaterial cloaking, based on transformation optics, describes the process of shielding something from view by controlling electromagnetic radiation. Objects in the defined location are still present, but incident waves are guided around them without being affected by the object itself.

Electromagnetic metamaterials respond to chosen parts of radiated light, also known as the electromagnetic spectrum, in a manner that is difficult or impossible to achieve with natural materials. In other words, these metamaterials can be further defined as artificially structured composite materials, which exhibit interaction with light usually not available in nature (electromagnetic interactions). At the same time, metamaterials have the potential to be engineered and constructed with desirable properties that fit a specific need. That need will be determined by the particular application.

The artificial structure for cloaking applications is a lattice design – a sequentially repeating network – of identical elements. Additionally, for microwave frequencies, these materials are analogous to crystals for optics. Also, a metamaterial is composed of a sequence of elements and spacings, which are much smaller than the selected wavelength of light. The selected wavelength could be radio frequency, microwave, or other radiations, now just beginning to reach into the visible frequencies. Macroscopic properties can be directly controlled by adjusting characteristics of the rudimentary elements, and their arrangement on, or throughout the material. Moreover, these metamaterials are a basis for building very small cloaking devices in anticipation of larger devices, adaptable to a broad spectrum of radiated light.

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