Tag: wavelength

The Future of Computing: Towards a Quantum Internet

quantun_internetFor decades, the dream of quantum computing – a system that makes direct use of quantum-mechanical phenomena, such as superposition and entanglement, to perform operations on data- has been just that. Much the same is true of principles that expand on this concept, such as quantum encryption and a quantum internet. But thanks to ongoing studies and experiments by researchers and scientists, that dream may be closer to fruition than ever.

This time the progress comes from a research team out of Professor Nicolas Gisin lab’s in the physics department at the University of Geneva. The team achieved the teleportation of the quantum state of a photon – this time, the photon’s polarization – to a crystal-encased photon more than 25 kilometers (15.5 miles) away. The distance breaks the previous record of 6 kilometers (3.7 miles) set 10 years ago by the same team using the same method.

quantum_crystalThis is the latest in a series of experiments the group, led by physicist Félix Bussières, have conducted over the last decade in an effort to better understand quantum data transfer. In this particular experiment, the researchers stored one photon in a crystal, essentially creating a solid-state memory bank. They sent another photon of a different wavelength 25 km away through optical fiber, whereupon they had it interact with a third photon.

Because the first two photons were entangled – a quantum property whereby particles can speak to each other across an infinite distance – the interaction sent the data to the photo stored in the memory bank, where the team was able to retrieve it. Or as the team explained, using pool balls as an anology:

It is a bit like a game of billiards, with a third photon hitting the first which obliterates both of them. Scientists measure this collision. But the information contained in the third photon is not destroyed – on the contrary it finds its way to the crystal which also contains the second entangled photon.

quantum-entanglement3This is all in keeping with the concept of quantum teleportation – the moving of quantum data from one location to another without having to travel the distance between them. That means that the speed at which data moves isn’t necessarily limited by the constraints of space and time. In that sense, it’s easier to think of this kind of teleporting not as a “beam me up” scenario, but as a kind of instantaneous awareness between two points.

While this may not sound as exciting as Ursula K. Le Guin’s Ansible communicator, the Alcubierre warp drive, or the “Star Trek”-style transporter, it opens up startling possibilities. For instance, in addition to bringing us closer to hard drives that can store quantum bits (aka. qubits), this is a major step in the direction of a quantum internet and encryption- where information is sent around the world instantaneously and is extremely secure.

quantum-teleportation-star-trails-canary-islands-1-640x353This also opens doors for space exploration, where astronauts in space, rovers on Mars, and satellites in deep space will be able to communicate instantly with facilities here on Earth. For non-quantum physicists, the novel aspect of this experiment is that the team achieved teleportation of data across the kind of optic fiber that forms the basis of modern-day telecommunications, which means no major overhaul will be needed to make quantum internet a reality.

As physicists continue to push the boundaries of our understanding about the quantum world, we’re getting closer to translating these kinds of advancements in market applications. Already, quantum computing and quantum encryption are making inroads into the sectors of banking security, medical research and other areas in need of huge computing muscle and super-fast information transfer.

^With the rise of a potential quantum Internet on the horizon, we could see the next jump in communication happen over the next couple of decades. So while we’re a long way off from trying to pry quantum teleportation and entanglement from the grip of the theoretical realm, scientists are making headway, if only a handful of kilometers at a time. But every bit helps, seeing as how routing stations and satellites can connect these distances into a worldwide network.

In fact, research conducted by other labs have not only confirmed that quantum teleportation can reach up to 143 km (89 miles) in distance, but that greater and greater properties can be beamed. This distance is especially crucial since it happens to be close to what lies between the Earth and a satellite in Low-Earth Orbit (LEO). In short, we humans could construct a quantum internet using optic cables or satellites, mirroring the state of telecommunications today.

And when that happens, get ready for an explosion in learning, processing and information, the likes of which has not been seen since the creation of the printing press or the first internet revolution!

Sources: cnet.com, technologyreview.com, nature.com

Powered by the Sun: Breakthrough Solar Cells

solar1In addition to becoming cheaper, and increasing in efficiency and yields, solar cell technology is also growing in terms of innovative design. By going beyond the conventional design of silicon panels and electrical cables, researchers are ensuring that solar technology can go farther. And the latest advances in design are especially far-sighted, aiming to merge solar technology with just about any surface, and even sending it into space.

In the former case, researchers at Michigan State University have created a fully transparent solar concentrator, which could turn any window or sheet of glass – from highrise buildings to the screens on smartphones and tablets – into a photovoltaic solar cell. And whereas other “transparent” solar panels have been designed in the past, this one is the first that truly lives up to the word.

transparent-solar-cellScientifically, a transparent solar panel is something of an oxymoron. Solar cells, specifically the photovoltaic kind, make energy by absorbing photons and converting them into electrons. If a material is transparent, by definition it means that all of the light passes through the medium. This is why previous transparent solar cells have actually only been partially transparent, and usually cast a colorful shadow.

To get around this limitation, the Michigan State researchers use a slightly different technique for gathering sunlight. Instead of trying to create a transparent photovoltaic cell, they used a transparent luminescent solar concentrator (TLSC), which consists of organic salts that absorb specific non-visible wavelengths of ultraviolet and infrared light, which they then luminesce (glow) as another wavelength of infrared light (also non-visible).

https://i0.wp.com/www.extremetech.com/wp-content/uploads/2014/08/transparent-luminescent-solar-concentrator-colorful.jpgThis emitted infrared light is guided to the edge of plastic, where thin strips of conventional photovoltaic solar cell convert it into electricity. Currently, the Michigan TLSC has an efficiency of around 1%, but they think 5% should be possible. On their own, these aren’t huge figures, but on a larger scale — every window in a house or office block — the numbers quickly add up to a significant electrical yield.

Moreover, the researchers are confident that the technology can be scaled all the way from large industrial and commercial applications, down to consumer devices, while remaining “affordable.” So far, one of the larger barriers to large-scale adoption of solar power is the intrusive and ugly nature of solar panels. But if large amounts of solar power can be produced from sheets of glass and plastic, it would go a long way to making the scaling process feasible.

solar_panel_origamiAnother major innovation comes from Brigham Young University, where researchers have been working with NASA’s Jet Propulsion Laboratory to address the challenge of Space-Based Solar Power. For some time, scientists have understood that a solar array in orbit of Earth would be ideally suited for solar power collection, since it would be immune to weather, cloud cover or diurnal cycles (aka. nighttime).

Unfortunately, getting solar cells into space is a bit of a problem. In order to be effective, solar panels need to be thin have a large surface area to soak up more rays. This makes it difficult to transport them into orbit, and requires that they be broken down,and flown up piece by piece, and then assembled once in orbit. Given the cost of mounting a sending a single rocket into orbit, this prospect becomes very costly very fast.

solar_panel_origami1However, the Brigham team came up with a simple and elegant solution to this problem, and found it in the form of origami. By working with complex origami folds, they were able to design a solar array that can shrink down to one-tenth of its original size. Folded up, the device is 2.7 meters (8.9 feet) across and can easily wrap around a spacecraft. Once it reaches space, the array would then unfold to become as wide as 25 meters (82 feet).

Given that solar panels deal with large, flat, thin structures, the origami concept seems like a natural fit. And this is not the first time that it has been used in space equipment design – in the 1990’s, Japanese astrophysicist Koryo Miura created a prototype for another folding solar panel. However, that project was abandoned for various reasons, not the least of which was lack of funding.

space-solar-headTo make the concept work and renew interest in the application, he Brigham team worked with Robert Lang, a world-renowned origami expert who also happens to be a mathematician and engineer and once worked at JPL himself. As Brian Trease, a mechanical engineer at the Jet Propulsion Laboratory, said:

He was trained as a physicist, used to work at JPL, and then got tired of the formal bureaucracy and left to start folding paper. Now he’s a world expert… We see value in going directly to any artist, even if they don’t have his credentials, because they have the thousands of hours or folding and tinkering to realize what can and can’t be done. Anytime you can bring in other disciplines, they just visualize things differently and bring in different solutions to your problems.

The new solar panels could be used to power spacecraft and potentially also on orbiting power stations that could wirelessly send energy to Earth via microwaves. A similar design could also be used on Earth to provide new options for portable solar power in remote locations. The same type of design might also be used in architecture or product design because of its unusual looks and function.

NASA_suntowerAccording to Trease, the Department of Defense has already been in touch with them regarding applications for soldiers in the field:

Soldiers right now might carry around 100 pounds, 15 of those pounds are batteries and fuel. If you can eliminate that, you’ve dramatically reduced their load… It’s different from opening an umbrella, because it can accommodate rigid material. You could do something like a deployable glass chandelier or a table. When it’s deployed, it looks like a flower blooming–it’s got a nice aesthetic to it.

In the next few weeks, Trease will also meet with other experts to consider different potential applications for space equipment, like antennas and reflectors, that could also deploy using origami. And given the rapidly-dropping prices associated with placing objects into orbit, this could prove to be the basis for the dream of Space-Based Solar Power – where all our energy needs are met by solar arrays in orbit that then beam them to Earth.

 

Source: extremetech.com, fastcoexist.com

Powered by the Sun: Boosting Solar Efficiency

solar1Improving the efficiency of solar power – which is currently the most promising alternative energy source – is central to ensuring that it an becomes economically viable replacement to fossil fuels, coal, and other “dirty” sources. And while many solutions have emerged in recent years that have led to improvements in solar panel efficiency, many developments are also aimed at the other end of things – i.e. improving the storage capacity of solar batteries.

In the former case, a group of scientists working with the University of Utah believe they’ve discovered a method of substantially boosting solar cell efficiencies. By adding a polychromat layer that separates and sorts incoming light, redirecting it to strike particular layers in a multijunction cell, they hope to create a commercial cell that can absorb more wavelengths of light, and therefor generate more energy for volume than conventional cells.

EMSpectrumTraditionally, solar cell technology has struggled to overcome a significant efficiency problem. The type of substrate used dictates how much energy can be absorbed from sunlight — but each type of substrate (silicon, gallium arsenide, indium gallium arsenide, and many others) corresponds to capturing a particular wavelength of energy. Cheap solar cells built on inexpensive silicon have a maximum theoretical efficiency of 34% and a practical (real-world) efficiency of around 22%.

At the other end of things, there are multijunction cells. These use multiple layers of substrates to capture a larger section of the sun’s spectrum and can reach up to 87% efficiency in theory – but are currently limited to 43% in practice. What’s more, these types of multijunction cells are extremely expensive and have intricate wiring and precise structures, all of which leads to increased production and installation costs.

SolarCellResearchIn contrast, the cell created by the University of Utah used two layers — indium gallium phosphide (for visible light) and gallium arsenide for infrared light. According to the research team, when their polychromat was added, the power efficiency increased by 16 percent. The team also ran simulations of a polychromat layer with up to eight different absorbtion layers and claim that it could potentially yield an efficiency increase of up to 50%.

However, there were some footnotes to their report which temper the good news. For one, the potential gain has not been tested yet, so any major increases in solar efficiency remain theoretical at this time. Second, the report states that the reported gain was a percentage of a percentage, meaning that if the original cell efficiency was 30%, then a gain of 16% percent means that the new efficiency is 34.8%. That’s still a huge gain for a polychromat layer that is easily produced, but not as impressive as it originally sounded.

PolyChromat-640x353However, given that the biggest barrier to multi-junction solar cell technology is manufacturing complexity and associated cost, anything that boosts cell efficiency on the front end without requiring any major changes to the manufacturing process is going to help with the long-term commercialization of the technology. Advances like this could help make technologies cost effective for personal deployment and allow them to scale in a similar fashion to cheaper devices.

In the latter case, where energy storage is concerned, a California-based startup called Enervault recently unveiled battery technology that could increase the amount of renewable energy utilities can use. The technology is based on inexpensive materials that researchers had largely given up on because batteries made from them didn’t last long enough to be practical. But the company says it has figured out how to make the batteries last for decades.

SONY DSCThe technology is being demonstrated in a large battery at a facility in the California desert near Modeso, 0ne that stores one megawatt-hour of electricity, enough to run 10,000 100-watt light bulbs for an hour. The company has been testing a similar, though much smaller, version of the technology for about two years with good results. It has also raised $30 million in funding, including a $5 million grant from the U.S. Department of Energy.

The technology is a type of flow battery, so called because the energy storage materials are in liquid form. They are stored in big tanks until they’re needed and then pumped through a relatively small device (called a stack) where they interact to generate electricity. Building bigger tanks is relatively cheap, so the more energy storage is needed, the better the economics become. That means the batteries are best suited for storing hours’ or days’ worth of electricity, and not delivering quick bursts.

solarpanelsThis is especially good news for solar and wind companies, which have remained plagued by problems of energy storage despite improvements in both yield and efficiency. Enervault says that when the batteries are produced commercially at even larger sizes, they will cost just a fifth as much as vanadium redox flow batteries, which have been demonstrated at large scales and are probably the type of flow battery closest to market right now.

And the idea is not reserved to just startups. Researchers at Harvard recently made a flow battery that could prove cheaper than Enervault’s, but the prototype is small and could take many years to turn into a marketable version. An MIT spinoff, Sun Catalytix, is also developing an advanced flow battery, but its prototype is also small. And other types of inexpensive, long-duration batteries are being developed, using materials such as molten metals.

Sumitomo-redox-flow-battery-YokohamaOne significant drawback to the technology is that it’s less than 70 percent efficient, which falls short of the 90 percent efficiency of many batteries. The company says the economics still work out, but such a wasteful battery might not be ideal for large-scale renewable energy. More solar panels would have to be installed to make up for the waste. What’s more, the market for batteries designed to store hours of electricity is still uncertain.

A combination of advanced weather forecasts, responsive fossil-fuel power plants, better transmission networks, and smart controls for wind and solar power could delay the need for them. California is requiring its utilities to invest in energy storage but hasn’t specified what kind, and it’s not clear what types of batteries will prove most valuable in the near term, slow-charging ones like Enervault’s or those that deliver quicker bursts of power to make up for short-term variations in energy supply.

Tesla Motors, one company developing the latter type, hopes to make them affordable by producing them at a huge factory. And developments and new materials are being considered all time (i.e. graphene) that are improving both the efficiency and storage capacity of batteries. And with solar panels and wind becoming increasingly cost-effective, the likelihood of storage methods catching up is all but inevitable.

Sources: extremetech.com, technologyreview.com

 

Powered by the Sun: Microbead Solar Cells

solar3Despite how far solar cells have come in recent years, issues like production and installation costs have remained an ongoing obstacle to their full scale adoption. But as they say, obstacles are meant to be overcome, and can often produce very interesting solutions. For example, peel and stick solar panels that can be manufactured by a 3D printer are one option. Another is the recent creation of a solar cell as thin as a strand of hair. And as it happens, a third has just been unveiled.

This latest one comes to us from the University of Oslo, where researchers have come up with a way to produce silicon solar cells that are twenty times thinner than commercial solar cells. Typically, solar cells are fashioned out of 200-micrometer-thick (0.2mm) wafers of silicon, which given their average rate of power generation works out to about five grams of silicon per watt of solar power. Combined with all the silicon wasted in the production process, this makes for a very inefficient process.

Solar-Wafer-Solar-CellsOne way around this is to reduce the thickness of solar wafers, but this presents its own problems. As the wafer gets thinner, more light passes straight through the silicon, dramatically reducing the amount of electricity produced by the photovoltaic effect. Blue light, which has a short wavelength, can be absorbed by a very thin solar cell; but red light, which has longer wavelengths, can only be captured by thicker wafers.

Enter into this the breakthrough created by the Oslo researchers. Using a revolutionary technique involving microbeads – tiny plastic spheres that create an almost perfect periodic pattern on the silicon. Apparently, these beads force the sunlight to “move sideways,” ensuring a more uniform and powerful rate of absorption. Another trick is to dot the backs of each cell with asymmetric microindentations,which can trap even more solar energy.

solar_beadsUsing these techniques, silicon wafers can be created that measure a mere 10 micrometers in thickness but can do the job of a 200 micrometer cell. By using 95% less silicon, the cost of production drops considerably, which will reduce the cost of solar power installations and – more importantly – increase profits. With current production methods and costs, the profit margin associated with solar power is pretty negligible.

This latter aspect is especially important as far as commercial production comes into play. If we are to expect industries to adopt solar power for their energy needs, it has to be worth their while. At the moment, the Oslo researchers are in talks with industrial partners to investigate whether these methods can be scaled up to industrial production. But given the nature of their work, they seem quite confident that their technology could come to the market within five to seven years.

Stay tuned for more installments in the PBTS series!

Source: Extreme.tech