The Science of Being Invisible - Reality

The invisible Cloak similar to that in the movie Harry Potter can become reality in near future. Metamaterials provide the substance for making such a cloak. Metamaterials are the materials which are yet to be made by the engineering process that contains a mixture of a metal or plastic but it differs from the taylor made material in the sense that it's properties are not related to the base materials but are because of the geometry in which the materials are combined. These can perform certain things that are not possible with ordinary materials it can  affect the path of waves light waves and sound waves and it has a negative refractive index. Small scale achievement have been obtained but the use for making cloak is not far enough. It can also provide stealth to military equipments. So let's figure how the light behaves by passing through meramaterials.

The left is metamaterial and right is ordinary one 

How an object is visible to naked eyes it's simple it reflects and refracts the light waves which are electromagnetic in nature and these waves after reflection enters through our eyes to form the image of the object, but suppose if an object doesn't allows the light to reflect or refracts through it this is how one can become invisible. Meta materials uses the ideology that it allows the light to guide through it rather than reflecting it the electrons in metamaterial doesn't allow the electromagnetic waves to get reflected or refracted but helps them smoothly guiding through them, and the material will be invisible to human eye and it will cast no shadow. To accomplish this the metamaterial should have a negative refractive indes( reflective index is a property that tells how light passes through a medium), the negative refractive index will allow the light to flow through the surface of the object but the real challenge is in the wavelength of light for having negative refractive index the wavelength of the light should be more than the wavelength of metamaterial then it will work properly and it has to cover the entire visible spectrum ranging from 400 nanometers for violet to 700 nanometers for red,and this would require engineering a material whose dimensions would be one billionth of a meter.
The future is not far enough, sooner we will be able to produce these incredible materials and who knows what changes they might bring, one thing that has to be kept in mind is that all the things follow laws governed by physics seldom it is thought that this is unnatural or it violates physics that is not true.
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