What are Metamaterials ?

Metamaterials are man-made materials engineered to have properties that are not found in nature. They are designed to manipulate electromagnetic waves and fields in ways that regular materials cannot. Metamaterials get their unique properties not from their composition but from their precisely engineered internal structure. This structure is designed on a scale smaller than the wavelength of thephenomena they affect, such as the visible light spectrum. Metamaterials thus allow scientists to "go beyond nature" and realize materials properties that have hitherto only been imagined.

Negative Refraction Index

Metamaterials can be designed with a negative refractive index which is not found in nature. When light passes through a medium with negative refractive index, it bends in the opposite direction compared to natural materials. This counterintuitive behavior arises due to the carefully crafted responses of the metamaterial's sub-wavelength structure to electric and magnetic fields. Negative refraction opens up exciting possibilities for "superlenses" that can overcome the diffraction limit and hyperlenses that can concentrate light to nanoscale spots below the diffraction limit. It also enables the design of the first "invisibility cloak" that can bend light around objects rendering them effectively invisible. 

Super Resolution Imaging

Another application of negative refraction in metamaterials is super resolution imaging. By employing negative refraction, metamaterials can transfer sub-wavelength information from one surface to another, allowing the construction of a "hyperlens" that magnifies sub-diffraction limited features below 100 nanometers. This could revolutionize nanolithography, microscopy, and other applications requiring visualization and manipulation at the nanoscale. Active research aims to extend hyperlensing capabilities into visible and near infrared wavelengths for widespread use.

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