Breakthough research paves way for invisibility of light

The device was built by teams from Universitat Autònoma de Barcelona and an experimental group from the Academy of Sciences of Slovakia, using a semiconductor and ferromagnetic materials. The cylinder was constructed using high temperature superconductor material, easily refrigerated with liquid nitrogen and covered in a layer of iron, nickel and chrome. The researchers claim that the formula enabled a true invisibility cloak to be developed. Never before, they claim, has a device been created with such simplicity or exactness in theoretical calculations. The mathematical formula behind the design was discovered by Àlvar Sánchez, lecturer of the Department of Physics at UAB. Using an 'extraordinarily simple equation', the cylinder was developed using the precise measurement of magnetic fields and, within a few months, the experimental results were clear. The cylinder was completely invisible to magnetic fields, made whatever content in its interior invisible and fully isolated it from external fields. According to the researchers, the superconductor layer of the cylinder prevents the magnetic field from reaching the interior but distorts the external field and thus makes it detectable. To avoid detection, the ferromagnetic outer layer made of iron, nickel and chrome, produces the opposite effect. It attracts the magnetic field lines and compensates the distortion created by the superconductor, but without allowing the field to reach the interior. The global effect is said to be a completely non existent magnetic field inside the cylinder with absolutely no distortions in the magnetic field outside. The results of this research project also pave the way for possible medical applications. In the future, similar devices designed by UAB researchers could serve to block a pacemaker or a cochlear implant in a patient needing to undergo a magnetic resonance. The invention is published this week in the journal Science.