Invisibility Is Now A Reality?
One of the hottest fields in science right now is invisibility research. But invisibility is science fiction you say? That’s not necessarily true anymore.
In 2006, researchers at the Berkeley National Laboratory working with metamaterials, made a copper cylinder ‘invisible’ to microwaves. Then in 2009, researchers stepped up their game, and did the same thing with infrared light, which is only just below the visible light spectrum. The light that we use to see.
The researchers claim it’s only a matter of time before we can make things invisible to visible light.
What is metamaterial?
Metamaterials are artificial materials engineered to provide properties which may not be readily available in nature. These materials usually gain their properties from their own structure or the way they are built rather than what makes them up.
The materials the researchers are working with have a unique quality. A ‘negative refracting index’. This index is what bends light around the object you are trying to make invisible. For instance, when you put a pencil in water, and the object seems to bend at an odd angle, this is a ‘positive refracting index’.
The way a negative refracting index works, is very similar to a large rock in a small stream. The flowing water hits the rock, splits and flows around it. It then recombines behind the rock, and becomes a smooth stream again. This is how metamaterials operate.
How will this affect our lives?
There are wide ranging applications for this technology. Buildings could be made invisible to cell phone signals, planes and tanks could be made invisible to radar and certain imaging, devices in hospitals could be shielded from disruption by MRI scanners, reversing the Doppler effect, and nanocircuits for computers.
What are the drawbacks?
There has to be a catch you say. Well, there is. A few in fact.
The invisibility effect would work only for a specific range of wavelengths. You couldn’t be invisible to microwaves and infrared at the same time for instance. Only one specific wavelength of light. Also, you wouldn’t be able to move around if you were wearing a metamaterial ‘invisibility’ cloak. It would change the way the light bends around you and spoil the effect.
It will be a while before you’ll be able to don the invisibility cloak from Harry Potter, but researchers are steadily working towards it.
Ji, Chunlin (2009-01-16). “Summary: New algorithms developed to guide manufacture of metamaterials”
Richard W. Ziolkowski (2006-06). Metamaterials: Physics and Engineering Explorations. Wiley & Sons.
D. R. Smith (January 16, 2009). “Broadband Ground-Plane Cloak”. Science 323 (5912)