Scientists tout tunable electro-magnetic portal

Potter-esque secret doors just around the corner - they'll look a bit like mirrors, apparently

Researchers from the Hong Kong University of Science and Technology have published the concept of a gateway that can block electromagnetic waves but allow the passage of other entities.

Quoting Harry Potter and Philip Pullman's Dark Materials trilogy, the scientists claim that a 'hidden portal' is now one step closer to reality.

It's all part of ongoing research into exotic meta-materials that can bend light and render (very small) things invisible.

High tech, low humour

The Chinese gateway uses transformation optics and an amplified scattering effect from an arrangement of ferrite materials called single-crystal yttrium-iron-garnet to force light and other forms of electromagnetic radiation in complicated directions, thus creating the mysterious portal.

Previous attempts at an electromagnetic gateway were hindered by only capturing a small range of visible light or other forms of electromagnetic radiation. This new configuration of metamaterials can be manipulated to have high permeability, and are able to insulate the electromagnetic field that encounters it with an appropriate magnetic reaction.

Because of the arrangement's response to magnetic fields, it also has the added advantage of being tunable and can therefore be switched on and off remotely. Obviously, TechRadar calls for it be switched off permanently, before hordes of blood-thirsty zombies from the future discover it and pour through.

Dr Huanyang Chen from Hong Kong University of Science and Technology said, "People standing outside the gateway would see something like a mirror. However, whether it can block all visible light depends on whether one can make a metamaterial that has a negative refractive index from 300 to 800 nanometres."