Graphene may boost internet speed 100 times.

Using 'miracle material' graphene in telecommunications could dramatically make the internet a hundred times faster, a new study has found.

Researchers from the Universities of Bath and Exeter have demonstrated for the first time incredibly short optical response rates using graphene, which could pave the way for a revolution in telecommunications.

Every day large amounts of information is transmitted and processed through optoelectronic devices such as optical fibres, photodetectors and lasers. Signals are sent by photons at infrared wavelengths and processed using optical switches, which convert signals into a series of light pulses.

Ordinarily optical switches respond at rate of a few picoseconds - around a trillionth of a second. Through this study physicists have observed the response rate of an optical switch using 'few layer graphene' to be around one hundred femtoseconds - nearly a hundred times quicker than current materials.

Graphene is just one atom thick, but remarkably strong. Scientists have suggested that it would take an elephant, balanced on a pencil to break through a single sheet.

Already dubbed a miracle material due to its strength, lightness, flexibility, conductivity and low cost, it could now enter the market to dramatically improve telecommunications, researchers said.

"We've seen an ultrafast optical response rate, using 'few-layer graphene', which has exciting applications for the development of high speed optoelectronic components based on graphene," lead researcher Dr Enrico Da Como said.

"This fast response is in the infrared part of the electromagnetic spectrum, where many applications in telecommunications, security and also medicine are currently developing and affecting our society," said Da Como.

"The more we find out about graphene the more remarkable its properties seem to be. This research shows that it also has unique optical properties which could find important new applications," Co-Director of the Centre for Graphene Science at Bath, Professor Simon Bending added.

In the long term this research could also lead to the development of quantum cascade lasers based on graphene.

Quantum cascade lasers are semiconductor lasers used in pollution monitoring, security and spectroscopy. Few-layer graphene could emerge as a unique platform for this interesting application.

World’s first telescopic contact lens gives you Superman-like vision.

 An international team of researchers have created the first telescopic contact lens; a contact lens that, when it’s equipped, gives you the power to zoom your vision almost three times. Yes, this is the first ever example of a bionic eye that effectively gives you Superman-like eagle-eye vision.

As you can see in the photo above, the telescopic contact lens has two very distinct regions. The center of the lens allows light to pass straight through, providing normal vision. The outside edge, however, acts as a telescope capable of magnifying your sight by 2.8x. This is about the same as looking through a 100mm lens on a DSLR. For comparison, a pair of bird-watching binoculars might have a magnification of 15x. The examples shown in the image below give you a good idea of what a 2.8x optical zoom would look like in real life.

The main breakthrough is that this telescopic contact lens is just 1.17mm thick, allowing it to be comfortably worn. Other attempts at granting telescopic vision have included: a 4.4mm-thick contact lens (too thick for real-world use), telescopic spectacles (cumbersome and ugly), and most recently a telescopic lens implanted into the eye itself. The latter is currently the best option currently available, but it requires surgery and the image quality isn’t excellent.

To create a 1.17mm-thick telescope, the researchers — led by Joseph Ford of UCSD and Eric Tremblay of EPFL — had to be rather creative. The light that will be magnified enters the edge of the contact lens, is bounced around four times inside the lens using patterned aluminium mirrors, and then beamed to the edge of the retina at the back of your eyeball. The mirrors magnify the image 2.8 times, but also correct for chromatic aberration, resulting in a surprisingly high fidelity image. To switch between normal and telescopic vision, the central (normal, unmagnified) region of the contact lens has a polarizing filter in front of it — and then the wearer equips a pair of 3D TV spectacles. By switching the polarizing state of the spectacles (a pair of active, liquid crystal Samsung 3D specs in this case), the user can choose between normal and magnified vision.

In case you were wondering, these solutions all primarily exist for one reason: To help restore sight to people with age-related macular degeneration. AMD damages the high-resolution fovea at the center of the retina, but generally the low-resolution outer region (perifovea) still works. Without the fovea, people with AMD can’t make out fine details, such as type on a page. These telescopic spectacles, lenses, and implants focus light onto this outer region, giving people with AMD the ability to make out these details.

The current telescopic contact lens is made out of PMMA, a gas-impermeable polymer that old, uncomfortable contact lenses used to be made of. To bring their lens to market, the researchers will need to switch over to rigid gas permeable (RGP) polymers, which modern, comfortable contact lenses are made from. While these telescopic lenses are obviously intended for people who suffer from AMD, there’s nothing to prevent a healthy person from wearing them and achieving better-than-human (superhuman?) vision.

MIT researchers build an all-optical transistor.

Optical computing—using light rather than electricity to perform calculations—could pay dividends for both conventional computers and quantum computers, largely hypothetical devices that could perform some types of computations exponentially faster than classical computers.

But optical computing requires light particles—photons—to modify each other's behavior, something they're naturally averse to doing: Two photons that collide in a vacuum simply pass through each other.

In the latest issue of the journal Science, researchers at MIT's Research Laboratory of Electronics—together with colleagues at Harvard University and the Vienna University of Technology—describe the experimental realization of an optical switch that's controlled by a single photon, allowing light to govern the transmission of light. As such, it's the optical analog of a transistor, the fundamental component of a computing circuit.

Moreover, since the weird, counterintuitive effects of quantum physics are easier to see in individual particles than in clusters of particles, the ability to use a single photon to flip the switch could make it useful for quantum computing.

The heart of the switch is a pair of highly reflective mirrors. When the switch is on, an optical signal—a beam of light—can pass through both mirrors. When the switch is off, only about 20 percent of the light in the signal can get through.

The paired mirrors constitute what's known as an optical resonator. "If you had just one mirror, all the light would come back," explains Vladan Vuleti?, the Lester Wolfe Professor of Physics at MIT, who led the new work. "When you have two mirrors, something very strange happens."

Light can be thought of as particles—photons—but it can also be thought of as a wave—an electromagnetic field. Even though, on the particle description, photons are stopped by the first mirror, on the wave description, the electromagnetic field laps into the space between the mirrors. If the distance between the mirrors is precisely calibrated to the wavelength of the light, Vuleti? explains, "Basically, a very large field builds up inside the cavity that cancels the field coming back and goes in the forward direction." In other words, the mirrors become transparent to light of the right wavelength.

Clouding over

In the RLE researchers' experiment, the cavity between the mirrors is filled with a gas of supercooled cesium atoms. Ordinarily, these atoms don't interfere with the light passing through the mirrors. But if a single "gate photon" is fired into their midst at a different angle, kicking just one electron of one atom into a higher energy state, it changes the physics of the cavity enough that light can no longer pass through it.

Joining Vuleti? on the paper are lead author Wenlan Chen and Kristin M. Beck, both PhD students in his group; Robert Bücker of the Vienna University of Technology; and Michael Gullans, Mikhail D. Lukin and Haruka Tanji-Suzuki of Harvard.

For conventional computers, the chief advantage of optical computing would be in power management: As computer chips have more and more transistors crammed onto them, they draw more power and run hotter. Computing with light instead of electricity would address both problems.

Of course, clouds of supercooled atoms are not a practical design for the transistors in, say, a Web server. "For the classical implementation, this is more of a proof-of-principle experiment showing how it could be done," Vuleti? says. "One could imagine implementing a similar device in solid state—for example, using impurity atoms inside an optical fiber or piece of solid."

Going quantum

Quantum-computing applications may be more compelling. Bizarrely, tiny particles of matter can be in mutually exclusive states simultaneously, something known as superposition. Where a bit in a classical computer can be either on or off, representing 0 or 1, bits built from particles in superposition can represent 0 and 1 at the same time. As a consequence, they could, in principle, evaluate many possible solutions to a computational problem in parallel, rather than considering them one by one.

Primitive quantum computers have been built using laser-trapped ions and nuclear magnetic resonance, but it's hard to keep their bits—or "qubits," for quantum bits—in superposition. Superposition is much easier to preserve in photons, for exactly the same reason that it's hard to get photons to interact.

The ability to switch an optical gate with a single photon opens the possibility of arrays of optical circuits, all of which are in superposition. "If the gate photon is there, the light gets reflected; if the gate photon is not there, the light gets transmitted," Vuleti? explains. "So if you were to put in a superposition state of the photon being there and not being there, then you would end up with a macroscopic superposition state of the light being transmitted and reflected."

A photon-switched transistor has other implications for quantum computing. For instance, Vuleti? says, one of the first applications of a conventional transistor was to filter noise out of an electrical signal by feeding the transistor's output back into it. "Quantum feedback can cancel—to the extent allowed by quantum mechanics—quantum noise," Vuleti? says. "You can make quantum states that you wouldn't otherwise get."

The switch could also be used as a photon detector: If a photon has struck the atoms, light won't pass through the cavity. "That means you have a device that can detect a photon without destroying it," Vuleti? says. "That doesn't exist today. It would have many applications in quantum information processing."

"Energy consumption in computing devices is a big issue," says Jelena Vuckovic, a professor of electrical engineering at Stanford University. "The beauty of this approach is that it can really do switching at the single-photon level, so your losses are much smaller. You don't have to spend a lot of energy for each bit. Your bit is essentially included in a single photon."

Vuckovic believes that it should be possible to reproduce the MIT researchers' results in physical systems that are easier to integrate into computer chips. "It's exactly the same story, except that instead of using these ultracold atoms in the cavity, you use a microscopic cavity on a semiconductor chip on a semiconductor and you use a quantum dot grown inside of the semiconductor as an artificial atom," she says. "There would be extra steps that people would have to take in order to implement the right energy-level structure. But in principle, the physics could be translated to a platform that could be cascaded and more easily integrated."

Into the quantum internet at the speed of light.

The atom’s quantum information is written onto the polarization state of the photon.

Not only do optical fibers transmit information every day around the world at the speed of light, but they can also be harnessed for the transport of quantum information. In the current issue of Nature Photonics, a research team of Innsbruck physicists led by Rainer Blatt and Tracy Northup report how they have directly transferred the quantum information stored in an atom onto a particle of light. Such information could then be sent over optical fiber to a distant atom.

Thanks to the strange laws of quantum mechanics, quantum computers would be able to carry out certain computational tasks much faster than conventional computers. Among the most promising technologies for the construction of a quantum computer are systems of single atoms, confined in so-called ion traps and manipulated with lasers. In the laboratory, these systems have already been used to test key building blocks of a future quantum computer. "Currently, we can carry out successful quantum computations with atoms," explain Andreas Stute and Bernardo Casabone, both PhD students at the University of Innsbruck's Institute for Experimental Physics. "But we are still missing viable interfaces with which quantum information can be transferred over optical channels from one computer to another."

What makes the construction of these interfaces especially challenging is that the laws of quantum mechanics don't allow quantum information to be simply copied. Instead, a future quantum internet – that is, a network of quantum computers linked by optical channels – would have to transfer quantum information onto individual particles of light, known as photons. These photons would then be transported over an optical-fiber link to a distant computing site. Now, for the first time, quantum information has been directly transferred from an atom in an ion trap onto a single photon. The work is reported in the current issue of Nature Photonics by a research team led by Tracy Northup and Rainer Blatt.

Quantum networkers

The University of Innsbruck physicists first trap a single calcium ion in an ion trap and position it between two highly reflective mirrors. "We use a laser to write the desired quantum information onto the electronic states of the atom," explains Stute. "The atom is then excited with a second laser, and as a result, it emits a photon. At this moment, we write the atom's quantum information onto the polarization state of the photon, thus mapping it onto the light particle." The photon is stored between the mirrors until it eventually flies out through one mirror, which is less reflective than the other. "The two mirrors steer the photon in a specific direction, effectively guiding it into an optical fiber," says Casabone. The quantum information stored in the photon could thus be conveyed over the optical fiber to a distant quantum computer, where the same technique could be applied in reverse to write it back onto an atom.