22-12-2010, 03:28 PM
Prepared by:
Dhirendra Mishra Ankit vimal jain
Poornima Institute of Engg. And Technolgy, Jaipur
Dhirendra Mishra Ankit vimal jain
Poornima Institute of Engg. And Technolgy, Jaipur
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ABSTRACT
“Invisiblity” has not remained a thing of science fiction movie or story. Imagine when one will be able to disappear in the air and no one is able to see him like the Harry Potter invisibility Cloak. Scientist has discovered the devices which are able to bend the light around three dimensional objects making them to “disappear”. The materials used for the invisibility devices are artificially designed and research are being carried out since than the idea strike the mind of thinkers of invisibility. The breakthrough could lead to systems for rendering anything from people to large objects, such as tanks and ships, invisible to the eye – although this is still years off. The day is not for away when we have invisibility cloak large enough to hide us.
1. INTRODUCTION
The things which our eyes are not able to see are considered as “ Invisible”. Light is neither absorbed nor reflected by the objects, passing like water flowing around a rock. As a result, only the light from behind the objects can be seen. The devices which are going to make us hide are invisibility devices. Researchers at the University of California at Berkeley, whose work is funded by the American military, have engineered materials that can control
light’s direction of travel. The world’s two leading scientific journals, Science and Nature, are expected to report the results in near future. . The concept of invisibility would involve surrounding the object by a "metamaterial" . Meta-material is a type of composite material that has unusual electromagnetic properties. According to the researchers, light rays incident on the material would be bent around the object, only to emerge on the other side in exactly the same direction as they began. Although the work is only theoretical, the researchers reckon that materials invisible to radio waves could be produced within five years.
2. META-MATERIAL
The new "meta-materials," whose physical structure bends visible light in a way that ordinary materials don't, may help efforts to make an invisibility cloak that could guide light around an object so that neither a reflection nor a shadow would be created. Researchers have developed meta-materials that show these unusual light-bending abilities for other parts of the electromagnetic spectrum, notably for microwaves, but efforts to do this with visible light have been limited to flat, two-dimensional systems because the shorter the wavelength, as in visible light, the smaller the features of the man made metamaterial.