A New Metamaterial will Speed Up Computers

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A team of scientists from the Moscow Institute of Physics and Technology (MIPT) and the Landau Institute for Theoretical Physics in the Russian Academy of Sciences has proposed a two-dimensional metamaterial composed of silver elements, that refracts light in an unusual way. The research has been published on Nov. 18, 2015 in Optical Material Express. In the future, these structures will be able to be used to develop compact optical devices, as well as to create an 'invisibility cloak.'

The results of computer simulations carried out by the authors showed that it would be a high performance material for light with a wavelength from 400-500nm (violet, blue and light blue). Efficiency in this case is defined as the percentage of light scattered in a desired direction. The efficiency of the material is approximately 70% for refraction, and 80% for reflection of the light. Theoretically, the efficiency could reach 100%, but in real metals there are losses due to ohm resistance.

A metamaterial is a material, the properties of which are created by an artificial periodic structure. The prefix 'meta' (from the Greek μετ? -- beyond) indicates that the characteristics of the material are beyond what we see in nature. Most often, when we talk about metamaterials, we mean materials with a negative refractive index. When light is incident on the surface of such a material, the refracted light is on the same side of the normal to the surface as the incident light. The difference between the behaviour of the light in a medium with a positive and a negative refractive index can be seen, for example, when a rod is immersed in liquid.

The existence of substances with a negative refractive index was predicted as early as the middle of the 20th century. In 1976 Soviet physicist V.G. Veselago published an article that theoretically describes their properties, including an unusual refraction of light. The term 'metamaterials' for such substances was suggested by Roger Walser in 1999. The first samples of metamaterials were made from arrays of thin wires and only worked with microwave radiation.

Importantly, the unusual optical effects do not necessarily imply the use of the volumetric (3d) metamaterials. You can also manipulate the light with the help of two-dimensional structures -- so-called metasurfaces. In fact, it is a thin film composed of individual elements.

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