We generally hear interesting stories about weary travelers trudging across a seemingly never-ending expanse of desert to what they think is a lush oasis or people traveling on a hot afternoon notice a puddle of water which melts into thin air when approached. This optical phenomenon is known as mirage. The term mirage originates via the French word ‘mirage’ which originates from the Latin mirari, which means ‘to look at, to wonder at’.
Researchers from the University of Texas at Dallas have created a working cloaking device which has the ability to make objects disappear. The novel design makes use of sheets of carbon nanotubes (CNT) which has unique properties to conduct heat and transfer it to surrounding areas that makes it an ideal material to exploit the so-called “mirage-effect”. Just like a mirage, this steep temperature gradient causes the light rays to bend away from the object concealed behind the device, making it appear invisible. The research results also provide useful insights into the optimization of nanotube sheets as thermo-acoustic projectors for loud speaker and sonar applications, where sound is produced by heating using an alternating electrical current.
For those who have never spotted a mirage, there is no need to trek to the desert to see a mirage: they are very common on roads. The most spectacular mirages occur in wide expanses of flat land as too many hills, dips or bumps will prevent the refracted light from reaching your eyes.