Not only has the creation of invisibility cloaks well advanced, scientists are undergoing researches to make more things on earth disappear.
A group of engineering professors in Columbia Engineering School has achieved a breakthrough in creating photonic computer chips which can propagate light without slowing it down nor changing phase. A new material created by the researchers is a nanoscale structure that allows light to pass through as if it was traversing empty space, says Reuters. The Columbia scientists sculpted a cascading series of nanostructures smaller than light waves, resulting in a material that reverses what you would normally expect when light passes through a substance.
The implications and potential ramifications of this new technology are rather exciting, stated Extreme Tech. It will first have an impact on the biggest user of photonics: telecommunications. Next, because wireless signals are electromagnetic radiation, just like light, this new technology could be used to create highly directional antennae, and even faster wireless networks. Beyond that, you're then looking at computer chips that actually process data using light, said Sebastian Anthony of Extreme Tech.
We're very excited about this. We've engineered and observed a metamaterial with zero refractive index, said Serdar Kocaman, electrical engineering Ph.D. candidate at Columbia Engineering School. What we've seen is that the light disperses through the material as if the entire space is missing. The oscillatory phase of the electromagnetic wave doesn't even advance such as in a vacuum - this is what we term a zero-phase delay.
According to Chee Wei Wong, associate professor of mechanical engineering at Columbia, optical phase control of photons is crucial in order to fully control light dispersion. The research showed the possibility for light to propagate from point A to point B without accumulating any phase, spreading through the artificial medium as if the medium is completely missing in space, stated the Columbia Engineer School website. This is a big step forward in figuring out how to carry information on photonic chips without losing control of the phase of the light, said Wong. We're very excited about this.
With the speed of light in our control, we could make not only an object but an entire event disappear. According to new research by British physicists, it is theoretically possible to create a material which can make an entire event disappear.
The concepts are basically quite simple, said Paul Kinsler, a physicist at Imperial College London, who created the idea with colleagues Martin McCall and Alberto Favaro, stated Richard A. Lovett of National Geographic.
This space-time cloak would use special materials filled with metallic arrays designed to adjust the speed of light passing through, says Lovett.
Invisibility researcher Ulf Leonhardt, a physicist at the University of St. Andrews in the U.K., said that the concept of an event cloak is definitely an interesting idea and great fun, despite the challenges the projects may face.
All of the material parameters need to be time-varying in a very specific way, said Steve Cummer, a cloaking specialist at Duke University.
At the moment, there is no one who has figured out how to vary the time of parameters except in fiber optics, said Lovett.
The fiber optics experiment is quite a technological stretch, and it will take some time for sure.
Leonhardt added that cloaking an event lasting more than a few femtoseconds (one-millionth of a nanosecond) would require light from an immensely powerful laser.
Invisibility is not just about vision. Sound waves can also disappear - through acoustic cloaking devices, which potentially could make ships invisible to sonar.
Last month, a research was published on Physical review Letters pointing to scientists' discovery at Duke University in North Carolina of a method to make objects invisible to sound waves. This invisibility cloak for sound waves is made possible through a technique involves surrounding an object with several layers of plastic plates, each riddled with holes in a specific pattern. The pattern of holes causes the reflected sound waves to behave as if there were nothing but empty space where the object is. Theoretically, sonar hitting the cloaked object wouldn't detect a thing, reported Peter Pachal of PCMag.
At the Royal Society's Summer Science Exhibition in London, one of the 22 projects presented involved invisible materials called metamaterials, which are artificial materials engineered to have properties unavailable in nature, in which the microstructure is changed to create unusual properties such as bending of electromagnetic waves, said Katia Moskvitch, a tech reporter at BBC News.
The illusion of disappearance steps from bending light in an unnatural way, said Leonhardt, who was among the project leaders.
In the 'cloaking' device, you bend light around something so that you don't see the object, but you also don't see that the light has been bent - it enters the device in a straight line and it also leaves the device in the same direction in came from, as if nothing had happened to it, he told BBC News.
This makes objects undetectable and therefore invisible.
With invisibility cloaks, humans are becoming better at hiding. Now that we can control the flow of light, the fastest thing known to men, the real challenge may be to control the usage of scientific breakthroughs for the right purpose.