Can a material have negative refractive index?
In his original analysis Veselago pointed out that while nature allows for negative refractive indices, they can only occur in a dispersive medium – a material in which beams of light with different wavelengths are refracted in different directions.
How is metamaterial different from ordinary material?
Although such a collection of objects and their structure do not appear at an atomic level like a conventional material, a metamaterial can nonetheless be designed so that an electromagnetic wave will pass through as if it were passing through a conventional material.
How do you get negative refractive index?
Negative refraction can be obtained by using a metamaterial which has been designed to achieve a negative value for (electric) permittivity (ε) and (magnetic) permeability (μ); in such cases the material can be assigned a negative refractive index. Such materials are sometimes called “double negative” materials.
What is metamaterial used for?
Potential applications of metamaterials are diverse and include optical filters, medical devices, remote aerospace applications, sensor detection and infrastructure monitoring, smart solar power management, crowd control, radomes, high-frequency battlefield communication and lenses for high-gain antennas, improving …
What is negative refractive index?
A negative-index metamaterial causes light to refract, or bend, differently than in more common positive-index materials such as glass lenses.
What is double negative metamaterial?
Double negative media are materials in which the permittivity and permeability are both negative. The extraction of the effective permittivity and permeability for these DNG metamaterials from reflection and transmission data is treated.
Is graphene a metamaterial?
Graphene is a monolayer of carbon atoms arranged in a honeycomb structure which exhibits remarkable properties including high electron mobility, mechanical flexibility, and saturable absorption. With the tunable characteristic, graphene-based metamaterial absorber and reflectarray have been designed.
What is a negative index?
Negative indices are all exponents or powers that have a minus sign in front of them and are as result negative.
Do invisibility cloaks exist?
Harry Potter’s invisibility cloak might not be so fantastical after all. A team of researchers in Montreal claims to have successfully rendered an object invisible to broadband light, using a new technique dubbed, “spectral cloaking.”
What has a refractive index of 0?
A refractive index of zero implies that light enters a state of quasi-infinite phase velocity and infinite wavelength. It also means that every point within the metamaterial experiences a quasi-uniform phase of the light wave present, as though all the dipoles inside the metamaterial are oscillating in unison.
What is DNG material?
Metamaterials are artificially developed materials which can exhibit some extra ordinary electromagnetic property and no longer naturally found. The metamaterials with simultaneous negative permeability (μ) and permittivity (ε) are referred to as double negative (DNG) or negative refractive index (NRI) metamaterials.
Who invented metamaterials?
Sir John Pendry
Metamaterial inventor Sir John Pendry awarded the Julius Springer Prize for Applied Physics 2013.
How are negative index metamaterials used in science?
Currently, negative-index metamaterials are being developed to manipulate electromagnetic radiation in new ways. For example, optical and electromagnetic properties of natural materials are often altered through chemistry. With metamaterials, optical and electromagnetic properties can be engineered by changing the geometry of its unit cells.
Which is the best description of a metamaterial?
Metamaterials 1 Metamaterials. 2 Metamaterial Cloaking. 3 Drawn metamaterials. 4 Alternative Plasmonic Materials. 5 Progress in Optics. 6 Metasurfaces. 7 Composite Metamaterials: Types and Synthesis
Which is an example of a non LSPR metamaterial?
Non-LSPR metamaterials rely upon effective medium behavior of composite materials and examples are cloaks, hyperbolic metamaterials, and epsilon-near-zero (ENZ) materials. As a general note, most of the metamaterial implementations of transformation optics fall into the category of non-LSPR metamaterials.
Why are negative index materials important for Photonics?
One of the most exciting opportunities for metamaterials is the development of negative-index materials (NIMs). These NIMs bring the concept of refractive index into a new domain of exploration and thus promise to create entirely new prospects for manipulating light, with revolutionary impacts on present-day optical technologies.