Is invisibility cloak on its way to reality?

Invisibility cloak has hidden Harry Potter and hobbits from view and now, this sci-fi staple may be moving closer to reality!

Scientists at Queen Mary University of London (QMUL) have made an object disappear by using a composite material with nano-size particles that can enhance specific properties on the object's surface.

Researchers demonstrated for the first time a practical cloaking device that allows curved surfaces to appear flat to electromagnetic waves.

While the research might not lead to the invisibility cloak made famous in J.K Rowling's 'Harry Potter' novels quite yet, this practical demonstration could result in a step-change in how antennas are tethered to their platform. It could allow for antennas in different shapes and sizes to be attached in awkward places and a wide variety of materials.

Co-author Yang Hao said: "The design is based upon transformation optics, a concept behind the idea of the invisibility cloak. Previous research has shown this technique working at one frequency. However, we can demonstrate that it works at a greater range of frequencies making it more useful for other engineering applications, such as nano-antennas and the aerospace industry."

The researchers coated a curved surface with a nanocomposite medium, which has seven distinct layers (called graded index nanocomposite) where the electric property of each layer varies depending on the position. The effect is to 'cloak' the object: such a structure can hide an object that would ordinarily have caused the wave to be scattered.

The underlying design approach has much wider applications, ranging from microwave to optics for the control of any kind of electromagnetic surface waves.

First author Luigi La Spada said: "The study and manipulation of surface waves is the key to develop technological and industrial solutions in the design of real-life platforms, for different application fields.

Spada added, "We demonstrated a practical possibility to use nanocomposites to control surface wave propagation through advanced additive manufacturing. Perhaps most importantly, the approach used can be applied to other physical phenomena that are described by wave equations, such as acoustics. For this reason, we believe that this work has a great industrial impact."

The study appears in Scientific Reports.