New Journal of Physics reports:
In a nutshell:
“Transformation optics has paved the way for the development of optical devices that can realize novel functionalities that were thought to be possible only in science fiction. One such conceptual device that has attracted great public interest is a gateway that can block electromagnetic waves but that allows the passage of other entities. This device can be viewed as an implementation of a ‘hidden portal’ mentioned in fiction. However, the feasibility of such devices is limited by the very complex material parameters and the narrow bandwidth.”
Wider implications. As there has been extensive work (both theoretical and experimental) on the design of double negative media (DNM) at various wavelengths, it would be reasonably feasible for the present gateway to be realized in the near future. Although it is still far away from hidden entrances like ‘platform 93⁄4’ in the Harry Potter novels, the interesting physics may fuel further research interest in transformation optics. The important message is that transformation optics can do more than making invisibility cloaks, it can actually generate all sorts of optical illusion effects.”
I wasn’t sure of the hidden portal/invisibility cloak connection so I did some scouting around and found this:
http://www.howstuffworks.com/invisibility-cloak.htm (watch the video for the bottom line here).
What I learned is we’re a long way off from an invisibility cloak, cloaking device, or a portal. I still don’t get the connection between porting and cloaking. I guess it’s the portal that is cloaked. But let me tell you: that invisibility thing they’re showing in the video? It ain’t happenin’. It reminds me of those old farces from Shakespeare’s time. If you put on a fake beard and deepen your voice you will be mistaken for your brother; if you sit quietly under the table, nobody will see you. I don’t think those devices even fooled the groundlings back then, but one must suspend one’s disbelief when one is working with fiction. So for now, this cloaking/portaling reality is still just that. A farce. If you tell me you’re invisible, okay, I’ll believe you, but only for the sake of a good story, so please, make the punchline funny.
Otherwise, keep trying,