The Future is Here: Light-Bending Invisibility Cloaks!

predator-invisibilityInvisibility cloaks are fast becoming a reality. That is to say, they are moving out of the realm of science fiction and the theoretical and into the realm of science fact. However, issues remain when it comes to developing this technology for real-world applications. Outside of adaptive camouflage that merely allow objects to blend into the background, true invisibility cloaks suffer from the problem of angles.

To break it down, invisibility cloaks are based on the scientific principle of bending light around an object, thereby rendering it invisible to sight. The problem with every device based on this principle built to date is that it only worked if both the viewer and whatever was cloaked remained still. This, of course, is not entirely practical since it means that a cloaked object would only be invisible from one angle.

invisibility_cloakHowever, the latest effort to create a true cloak – developed at the University of Rochester – not only overcomes some of the limitations of previous devices, but relies on inexpensive, readily available materials in a novel configuration. For the first time ever, researchers have made a cloaking device that works multidirectionally in three dimensions and uses no specialized equipment, but four standard lenses.

As well as at least partially solving the viewpoint problem, the Rochester cloak also leaves the background undisturbed, without any warping, as has appeared in other devices. As Joseph Choi, a professor of physics at Rochester University John Howell, explained:

There’ve been many high tech approaches to cloaking and the basic idea behind these is to take light and have it pass around something as if it isn’t there, often using high-tech or exotic materials. This is the first device that we know of that can do three-dimensional, continuously multidirectional cloaking, which works for transmitting rays in the visible spectrum.

invis_cloak_rochIn order to both cloak an object and leave the background undisturbed, the researchers determined the lens type and power needed, as well as the precise distance to separate the four lenses. To test their device, the off-the-shelf lenses were placed at such a distance from each other so as to allow the light to act in specific ways – first focusing it down to a fine point through one lens, then again through the next, and then repeated.

This bends the light so that an object in the ring-shaped cloaking field is not visible to a person peering through the array. To be sure, they placed the object being viewed through the lenses in front of a grid background, and then shifted the viewing angle. In all cases, with the grid background appeared perfectly normal, with no discontinuity appearing behind the cloaked object.

invisibility_cloak1Their simple configuration improves on other cloaking devices, but it’s not perfect. As Choi explained, the the cloak bends light and sends it through the center of the device, so the “on-axis region cannot be blocked or cloaked.” This means that the cloaked region is shaped like a doughnut. In addition, the cloak has edge effects, but these can be reduced by using larger lenses, and the team has some more complicated designs to address the other issues.

For the time being, the technology isn’t exactly workable as far as Predator-style invisibility cloaks are concerned. However, Howell and Choi had some more benign applications in mind, such as allowing surgeons to operate without their view being obstructed by their own hands. Also, such a device could be used to allow truck drivers or even regular commuters see through their vehicle’s blind spots.

And, because the setup is so simple, anyone can grab some lenses and give it a try. You can find instructions for doing so on the Rochester University website, and a paper describing the research on arXiv. And of course, the University of Rochester was sure to provide a video of the cloak being tested out. Check it out below:


Sources:
cnet.com, arxiv.org, rochester.edu

The Future is Here: World’s First “Invisible” Building

tower-infinity-seoul-south-koreaAll over the globe, governments and design firms are looking to create living examples of arcologies. Merging next-generation architectural with ecological sustainability, this futuristic concept is now becoming a reality, with projects ranging from Masdar Eco City in Dubai, to Crystal Island in Moscow, and China’s Shanghai Tower.

Not to be outdone, South Korea has proposed an equally audacious building plan that calls for the construction of a 450 meters tower that uses the latest in optical technology to render itself virtually invisible. Known as Tower Infinity, or City Tower, the building will be located in Cheongna (near the Incheon Airport just outside of Seoul) and will use the same technology that military contractors do to create “adaptive camouflage”.

F:tower infinityemailout120612 to gdskti-INVISIBIL-RESOLUTIThis involves fitting the building with a high-tech LED facade that integrates projectors and 18 strategically placed optical cameras. These cams will snap real-time pictures of the area directly behind the building, digitally stitch them into a panorama, and project them back onto the building’s reflective surface. This will create the illusion that viewers are looking straight through the building, making it appear to blend into the skyline at certain times of day.

According to GDS – the design firm behind Tower Infinity’s creation – the purpose of the building is largely symbolic. According to their website:

The tower subtly demonstrates Korea’s rising position in the world by establishing its powerful presence through diminishing its presence. Korea will have the unique position of having the ‘best’ tower by having an ‘anti-tower.

tower_infinityAnd while no word has been given yet on the relationship between the structure’s invisibility and planes from the nearby airport, it seems logical to stress that the building’s “invisibility cloak” is not perfect, nor is it meant to be. While it is able to generate an image that allows it to blend into the natural environment more readily, the building still leaves a translucent outline when at full power.

GDS also indicated that the purposes of the building go beyond the symbolic. In addition to showcases Korea’s presence in the global economy, the technology can be used for advertising and entertainment. As the company said in a statement:

This same technology also allows the tower to become a 450-meter-tall billboard screen and urban focal point for all arriving at Incheon,

The tower will house a 4D theater, a water park, landscaped gardens, and the third-highest observation deck in the world. Basically, it is intended as a tourist mecha in addition to everything else, which makes sense given its strategic location close to a major airport.

Source: cnet.news.com, gdsarchitects.com

The Future is Here: The Invisibility Cloak!

quantum-stealth-fieldInvisibility cloaks have long been considered the next frontier of modern warfare. With stealth aircraft, stealth ships and even stealth tanks in service or on well on their way, it seems like the time is ripe for a stealth soldier. But difficulties remains. Whereas cloaking planes, ships and tanks is a matter of simply coating them in materials that can obscure them from radar and thermal imagine, soldiers need camouflage that can move, bend and flex with them.

In recent years, the efforts to produce a working “invisibility cloak” have born considerable fruit. And while most of these took the form of large, cumbersome, desk-mounted constructions that were more of a proof of concept for the material being tested, they did demonstrate that the technology itself worked. This was certainly true of the “cloak” which was created by scientists at Duke University in November of 2012.

INVISIBILITY-CLOAKAnd then came news the following month that a Canadian company named Hyperstealth developed a material that renders the wearer “completely invisible by bending light waves around the target.” Known as “Quantum Stealth”, this true cloak is an apparent follow-up to their SmartCamo – a material that could reportedly adjust its camouflage markings to match its surroundings – that was released at the International Camouflage Symposium in 2010.

Unfortunately, due to security reasons, little was ever known about SmartCamo other than its reported abilities. The same holds true for Quantum Stealth, which the company has been forced to remain clandestine about due the demands of the US Army, to whom they are contracted. So until such time as it enters widespread use, the details and inner workings of the technology will remain inaccessible.

invisibility_cloak1Luckily, the University of Texas in Austin is under no such constrictions, and it is from them that the latest and greatest news comes. In addition to being composed of conventional materials, their new cloak measures a mere 166 micrometers thick and is capable of obscuring an object from multiple directions at once. And though it may not be able to render a soldier truly invisible, it does render them all but invisible to radar detection, which is the intent here.

The fabrication process involved placing a 66µm-thick sheet of carbon (or a metascreen) onto a a 100µm-thick sheet of flexible polycarbonate. The copper is patterned specifically so that the scattered light from the cloak and the cloaked object cancel each other out. This flexible sheet also allows the cloak to conform to the shape of the object, or person, and provides cloaking from microwave radiation from all directions.

invisibility_cloak_uoftNow here’s where things get literal. The researchers responsible for this breakthrough have indicated that, in theory, this cloak could be used to cloak visible light as well. After all, microwaves, infrared and visible light are all physically identical; they are just waves that oscillate at different frequencies. And their design would be more capable of doing this than any cloak composed of metamaterials.

Still, size and scale are still an issue. Whereas their new patterned material scattering technique is capable of hiding an object from multiple directions, it also inversely scales with wavelength. That means that it is only capable of hiding micrometer-scale objects from 400-800THz of visible light. Still, this is exciting news and a step in the right direction!

Before we know it, stealth troopers could be marching all over the planet, invisible to the naked eye and any means of radar detection… Holy crap, what a scary thought! Is it too late to rethink this technology?

future_soldierSource: Extremetech.com, (2)

The Future is Here: Invisibility Cloaks (Cont’d)

An update on the ongoing efforts to create invisibility technology has been bearing some pretty interesting fruit. Earlier this year, scientists at Berkeley announced that they were working on a suit that would be capable of bending light around it. Unlike adaptive camouflage, this technology would not merely broadcast a background image to conceal a soldier, but would render them virtually invisible to the naked eye.

Well guess what? Scientists at Duke University have finally created a cloak that works. Granted, it is only capable of concealing objects on the centimeter-scale, it is the only cloak of its kind that is capable of channeling incident light around itself, creating perfect invisibility. In all previous cases, the devices created reflected a certain degree of incident light, leaving the concealed object disguised but discernible.

In addition to the small scale on which it functions, the cloak has a few additional drawbacks. For now, the Duke invisibility cloak only works with microwave radiation; and perhaps more importantly, the cloak is unidirectional, meaning it only provides invisibility from one very specific direction. But that should hardly matter, seeing as how such a device even exists. With a little time, development, and a big fat DARPA contract, soon we may be seeing cloaking devices that are capable of concealing something as large as a person, a vehicle or even a building.

The Duke cloaking device, pictured at left, is composed of metamaterials – an artificial, man-made material that almost always have a negative refractive index. A negative refractive index allows for the creation of some interesting things, such as superlenses that go beyond the diffraction limit; or in this case, invisibility cloaks. Due to their unusual index, they are capable of refracting light around an object so a viewer does not see the object, but what is behind the object.

But in addition to metamaterials, the compositional materials also need a to be arranged in such a way that the illusion is perfect. After all, a 3D object has multiple sides, and the wearer has to be expected to turn a corner and change direction at some point. All previous designers in this case have struggled to fashion metamaterials that bend waves around corners without causing reflections. In this case, it was researcher Nathan Landy, a Duke University student, who arranged the metamaterials into the shape of a diamond to acheive the desired effect, since diamonds are apparently the best shape for minimizing reflections.

According to the Duke team, the next step is to expand on their design and make their cloak omnidirectional, meaning that it can bend light around the object from all directions. Don’t worry, I’m thinking some rather interested parties (i.e. every high-tech developer and military on the planet) is likely to be knocking on their door real soon!

Source: Extreme Tech

The Future is Here: Invisible Tanks!

Swedish-made CV90 with ADAPTIV panels

So far, we’ve heard of stealth fighters, stealth ships, and stealth suits. But what about stealth tanks? Why shouldn’t the mobile armored fighting vehicle be included in this race to make all weapons stealthy? Well its seems BAE (British Aerospace Marconi Electronic) Systems has decided to do just that. Working with the concept of Infra-Red imaging and its use on the modern battlefield, BAE has created the ADAPTIV camoflage system.

Basically, modern military vehicles use IR imaging for a number of purposes, namely target acquisition, night vision, homing and tracking. Ever since the late 80s and early 90s, any vehicle that did not have these capabilities found themselves at a marked disadvantage on the battlefield. After all, if you can see your enemy but they can’t see you, then you can destroy them with impunity!

A prime example of this happened during the Gulf War, where Iraqi armored formations were eviscerated simply they did not have the ability to see in the dark. While they moved about blind, US Abrams tanks simply targeted the enemy using their night vision and began picking them off one by one.

However, with every advanced army in the world employing IR technology, the pendulum has once again swung to defense. With all armies able to see an enemy vehicle’s thermal signature, any vehicle that has a way to hide it will now have the edge. That is the principle of ADAPTIV, which combines the idea of Infra-red concealment with the larger concept of adaptive camouflage.

Essentially, this consists of sheets of hexagonal panels that act as pixels when attached to the exterior of the vehicle. These pixels can individually change temperature very rapidly and combine to display an infrared image of the background scenery captured from cameras on board the vehicle, allowing even a moving tank to match its surroundings. BAE has also put together a library of images to display the heat signature of other vehicles, such as cars, trucks, and natural objects, such as large rocks.

Pretty cool huh? Already the technology has been proposed as being adaptable to more than just land vehicles. It can also be added to helicopters, surface ships, for commercial use, and can even send friendly identification signals. Check out the BAE promotional video below for a demonstration.