'Darkness Ray' Beams Invisibility From a Distance

KentuckyFC writes "Optical engineers generally build imaging systems with the best possible resolving power. The basic idea is that an imaging system focuses light into a pattern known as a point spreading function. This consists of a central region of high intensity surrounded by a concentric lobe of lower intensity light. The trick to improving resolution is narrowing and intensifying this central region while suppressing the outer lobe. Now optical engineers have turned this approach on its head by suppressing the central region so that the field intensity here is zero while intensifying the lobe. The result is a three-dimensional beam of darkness that hides any object inside it. The engineers say this region can be huge — up to 8 orders of magnitude bigger than the wavelength of the imaging light. What's more, the optics required to create it are simple and cheap: a lens consisting of concentric dielectric grooves. The team has even tested a prototype capable of hiding a 40-micrometre object in visible laser light."

Comments

Pictures or it didn't happen

[myth24601]

Pictures or it didn't happen.

Babinet called, wants his principleback.

[goombah99]

I think they must have skipped the chapter in their basic handbook of optics called Babinet's principle. Because they just re-invented Babinet focusing.

Please move on. There is nothing to see here ;-)

[140Mandak262Jamuna]

It has been easy to make objects invisible from time immemorial. Even though till about 14th century people did not really understand vision, and they thought some kind of rays emanate from the eyes that allows them to perceive it, they knew how to make objects invisible. Just turn the light off. Put it in a dark room without light, and no one can see it!

The technique here is a marginal improvement for practical purposes. There is a light in the room, still you can't see the object, objects that could be as much as 8 wavelengths of that monochromatic light, placed at the correct location. If there is any other source of light, the objects would be plainly visible due to scattering of that light. So it would be impractical to make an invisibility cloak out of it. You need to make the object disappear from all sources of light from all directions.

Though the technique is not going to lead to invisibility cloak, it is probably a great achievement to hide an object when there is one light source. Though people would think is 1 is pretty close to zero, in reality, there is a huge difference between 1 light source and no light source. It is a good great achievement, collect your brownie points scientists.

For others, please move on there is nothing to see here.