Scientists closer to making invisibility cloak a reality

Mar 05, 2009

J.K. Rowling may not have realized just how close Harry Potter's invisibility cloak was to becoming a reality when she introduced it in the first book of her best-selling fictional series in 1998. Scientists, however, have made huge strides in the past few years in the rapidly developing field of cloaking. Ranked the number five breakthrough of the year by Science magazine in 2006, cloaking involves making an object invisible or undetectable to electromagnetic waves.

A paper published in the March 2009 issue of SIAM Review, "Cloaking Devices, Electromagnetic Wormholes, and Transformation Optics," presents an overview of the theoretical developments in cloaking from a mathematical perspective.

One method involves light waves bending around a region or object and emerging on the other side as if the waves had passed through empty space, creating an "invisible" region which is cloaked. For this to happen, however, the object or region has to be concealed using a cloaking device, which must be undetectable to electromagnetic waves. Manmade devices called metamaterials use structures having cellular architectures designed to create combinations of material parameters not available in nature.

Mathematics is essential in designing the parameters needed to create metamaterials and to show that the material ensures invisibility. The mathematics comes primarily from the field of partial differential equations, in particular from the study of equations for electromagnetic waves described by the Scottish mathematician and physicist James Maxwell in the 1860s.

One of the "wrinkles" in the mathematical model of cloaking is that the transformations that define the required material parameters have singularities, that is, points at which the transformations fail to exist or fail to have properties such as smoothness or boundness that are required to demonstrate cloaking. However, the singularities are removable; that is, the transformations can be redefined over the singularities to obtain the desired results.

The authors of the paper describe this as "blowing up a point." They also show that if there are singularities along a line segment, it is possible to "blow up a line segment" to generate a "wormhole." (This is a design for an optical device inspired by, but distinct from the notion of a wormhole appearing in the field of gravitational physics.) The cloaking version of a wormhole allows for an invisible tunnel between two points in space through which electromagnetic waves can be transmitted.

Some possible applications for cloaking via electromagnetic wormholes include the creation of invisible fiber optic cables, for example for security devices, and scopes for MRI-assisted medical procedures for which metal tools would otherwise interfere with the magnetic resonance images. The invisible optical fibers could even make three-dimensional television screens possible in the distant future. The effectiveness and implementation of cloaking devices in practice, however, are dependent on future developments in the design, investigation, and production of metamaterials. The "muggle" world will have to wait on further scientific research before Harry Potter's invisibility cloak can become a reality.

More information: The paper is co-authored by Allan Greenleaf of the University of Rochester; Yaroslav Kurylev of University College London; Matti Lassas of Helsinki University of Technology; and Gunther Uhlmann of the University of Washington. To read this article in its entirely, visit www.siam.org/journals/sirev/51-1/71682.html

Source: Society for Industrial and Applied Mathematics

Explore further: Christmas cracker pulling: How to send everyone home a winner

add to favorites email to friend print save as pdf

Related Stories

Fingers pointed as climate talks deadlock

9 hours ago

Accusations flew at deadlocked UN climate talks in Lima on Saturday, as the United States warned that failure to compromise could doom the 22-year-old global forum.

Fun cryptography app pleases students and teachers

19 hours ago

Up on Google Play this week is Cryptoy...something that you might want to check out if you or someone you know wishes entry into the world of cryptography via an educational and fun app. You learn more about ciphers and keys; you ...

Recommended for you

Why are UK teenagers skipping school?

10 hours ago

Analysis of the results of a large-scale survey reveals the extent of truancy in English secondary schools and sheds light on the mental health of the country's teens.

Fewer lectures, more group work

11 hours ago

Professor Cees van der Vleuten from Maastricht University is a Visiting Professor at Wits University who believes that learning should be student centred.

User comments : 8

Adjust slider to filter visible comments by rank

Display comments: newest first

holoman
1 / 5 (1) Mar 05, 2009
old news
axemaster
1 / 5 (1) Mar 05, 2009
Yeah, this is very old news indeed.
SDMike2
1 / 5 (1) Mar 05, 2009
And it took us only a few years to do this. No wonder UFOs are so hard to see.

If I put one of these cloaks around my desert house would it stay cool?
malapropism
1 / 5 (1) Mar 05, 2009
Do people commenting here not understand the concept of a "review paper"?
out7x
1 / 5 (1) Mar 06, 2009
This "invisibility" would only apply to a single frequency. Useless for most purposes.
HenkZw
not rated yet Mar 06, 2009
I also read about the metamaterials in older news, but the use of the material to create optical wormholes seems new.
Nederluv
not rated yet Mar 06, 2009
This "invisibility" would only apply to a single frequency. Useless for most purposes.


That's a good thing. Complete invisibility is dangerous. I would rather have privacy than a 3D television. Besides, who would want 3D TV when you can get Virtual Reality!?
Schoey
3 / 5 (2) Mar 06, 2009
Does anybody truly believe that cloaking will be used for anything but military purposes?
Come on....let's shift the millions in funding from this ridiculous project into solving real world problems. "Planet America" via military force is never going to materialize, so lets forget dribble like "Invisibility cloaks"....wake up world.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.