Harry Potter`s `invisibility cloak` comes closer to reality

London: Scientists have designed a new invisibility cloak which can hide objects over a wide range of frequencies, taking us a step closer to Harry Potter styled cloak.

The current designs can conceal objects at specific wavelengths of light or microwaves and US physicists have found that at other frequencies, it actually make things more visible, not less, a news website reported. Prof Andrea Alu, from the University of Texas at Austin, said if you want to make an object transparent at all angles and over broad bandwidths, their cloak is a good solution. The study suggested that a cloak that allows complete invisibility is "impossible" with current passive designs. However, Alu said that a much more promising avenue is "active" cloaking technology- designs which rely on electrical power to make objects "vanish". Alu`s team have proposed a new design which uses amplifiers to coat the surface of the object in an electric current. According to the researcher, this ultrathin cloak would hide an object from detection at a frequency range "orders of magnitude broader" than any available passive cloaking technology. Cloaking materials could have applications in the military, microscopy, biomedical sensing, and energy harvesting devices. The research is published in Physical Review Letters.