College Park (MD) - Researchers at the University of Maryland have developed a cloaking device which can now hide objects in a much wider portion of the visible spectrum of light. An observer could even see what's behind the object, just as if the obstruction wasn't there. While not quite up to Romulan standards, the application does work in two dimensions and on very small objects.
A research team of physicists, led by Igor Smolyaninov, has built a new cloaking device built upon previous cloaking technology developed at Purdue University by Vladimir Shalaev earlier this year. Shalaev's system was somewhat limited in that only a single wavelength of red light could be cloaked, that of 632.8 nm. This new device works on a much larger spectrum of visible light, though it is still limited to light around 500nm and it does have other flaws. Moving up or down from a 2D vantage point renders the field null and the object becomes visible. There are also some indications along edges, and any light which happens to hit the device perfectly centered is also visible.
The cloaking device itself is a series of gold/plastic concentric rings only 10,000 nm across at the widest point built atop a gold substrate. The gold/plastic provides a property which allows photons entering the rings to appear to be reflected around to the other side, effectively hiding whatever is placed in the middle. Currently, a polarized form of cyan light projected from a very small fiber optic emitter is converted immediately into plasmons. Plasmons are essentially waves of electrons "rippling" along the surface. Because of the properties of gold/plastic in a vacuum, the plasmons are directed to the other side of the device where they are ejected again as photons.
Discrepancies in the cloaking field come from the fact that plasmons cannot be directed or moved in three dimensions. The curvature near the edges, and the exact dead-center target of incoming light (where the photon doesn't know to go right or left), cannot create the plasmonic effect. As a result, the photons at those locations bounce off as visible light, thereby disrupting the cloak.
Previous cloaking efforts have yielded only single wavelength cloaking abilities or EM frequencies which were not visible to the human eye. These new frequencies operate around 500nm (cyan) and allow for a much wider range of frequencies to pass through with full operation.
When microwave cloaks were first created using magnetic properties about a year ago, scientists then believed the idea of cloaking visible light was decades away. This was largely due to the manner in which that microwave cloak was implemented. However, the cloaking effect of visible light has already happened twice this year. And whereas these small steps may be nowhere near as exciting as "engage the cloak" sequences on Star Trek, the reality now exists to direct photons plasmonically where needed, possibly for specific purposes at the scales this device operates.
Ultimately, as science continues to push the envelope in all fields of research, the most significant benefit from this technology could be optical applications within integrated circuits, or what we would call the base of photonic computers. This story could ultimately prove to be the first step in a completed research project for a photonic computing application. It wil be the one we'll read about in just a few years.