Nano Ceramics: The New Featherweight Champion


1-Ceramics New-Featherweight-Champion-Nano-Ceramics_heroLight as a feather and tough as steel. Those are the two properties of the ideal material, and they don’t usually come together. Ceramics, be they new or ancient, are typically strong and light, but always brittle: their tendency to shatter has long kept them out of the category of “ideal.”

But now, thanks to researchers at the California Institute of Technology, the world’s oldest malleable material is now the strongest, lightest stuff on the planet. And, oddly, it’s flexible to boot. There will be no more chipped urns for the antiquarians of the future.

The trick is to construct the material on the nano level. To do that, Julia R. Greer, a professor of materials science and mechanics at the university, used a technique called two-photon lithography. In essence, a laser works its way through a liquid polymer, slowly hardening it nanometer by nanometer. Once this initial structure has been fully written, a nano ribbon of aluminum oxide (a ceramic) is wrapped onto the exterior. Then the polymer on the interior is etched away, leaving nothing but a ceramic lattice, made of tubes a micron in diameter. And the walls of those tubes are a mere 10 nanometers thin.

A fractal nanotruss. Image: Caltech.edu

Thin and Strong

Paradoxically, it’s the extreme thinness that gives the material its strength. “It enables you to get as close to an ideal as possible,” says Greer. Usually, when force is applied to a material, it fractures wherever there are flaws. But with the precision that comes from Greer’s method, the ceramic lattice is nearly flawless, so buckling occurs well before any fracture. When compressed by nearly 50 percent, the structure was still able to pop back to its original shape. A similar structure, with a wall thickness of 50 microns, shattered. And metals built to the same specs were nowhere near as strong.

1-Ceramics New-Featherweight-Champion-Nano-Ceramics_hero

Architected structures with nanometer-sized solids merge structural and material properties into a single “meta-material.” Image: D. Jang / Caltech.edu

The lightness has as much to do with the material as with the structure, which is more air than matter. “You can no longer look at the effect of the structure only, or material only,” says Greer. “Now you have to look at them together.”

Future Potential

The potential applications for the strongest, lightest material—which happens to be flexible—are, of course, many. Airborne uses, where weight is crucial, abound. The skin of airplanes, for instance, might be one of the first places the material might be put to use. Balloons could be made to float without adding a gas. Just a minimal vacuum at the opening and the entire balloon would become lighter than air.

Batteries could be made worlds lighter. Tiny biomimicking devices could use the ceramic scaffolding. And, as ceramics make excellent thermal buffers, the thinnest of ceramic sheets could be used anywhere two temperatures need to be kept from each other.

One could also, conceivably, print out lightweight, tear-proof, damage-proof sheets. Stack a few of those together (well, more than a few) and you’ve got a seemingly impossible construction unit. “It feels like a brick, it’s as strong as a brick, if you drop it will never shatter. Lighter than a feather and damage proof,” says Greer of the potential future. “Basically, we’ve completely changed the world.”

Before that change can be put to use, Greer and her colleagues need to find a faster way to process the ceramic. The two-photo lithography is an excruciatingly slow process. Though it can accurately create complex structures, each feature must be written into the polymer. “To scale something up, it would have to be new technology,” says Greer.

Once that technology is worked up and disseminated we’ll be living in a lighter, stronger, more clay-like world.

6 ideas to watch from MIT Technology Review’s 35 Innovators Under 35 list


imagesCAMR5BLR Einstein Judging a Fish

Summary:

From a nuclear reactor that runs on nuclear waste to a totally new way to transfer money, big ideas are coming out of the younger generation.

Business person with idea lightbulb

Every year, MIT Technology Review releases a list of people less than 35 years old who are working on the most exciting innovations on Earth (or beyond). The list has featured Marc Andreessen (1999), Mark Zuckerberg (2007) and Jack Dorsey (2008), but also tons of technologists and scientists working on highly meaningful, but far less visible, projects.

The 2013 list, which was published this week, contains a few familiar names: Leah Busque (TaskRabbit), Eric Migicovsky (Pebble) and Matt Rogers (Nest). Their ideas were so big that they already feel familiar. Here are a few of the less-famous ideas worth highlighting.

Turn any surface into a source of power

We think of solar cells as large, rigid panels that sit on the top of buildings. Stanford professor Xiaolin Zheng wants that to change. She developed small stickers — just a centimeter across — that can be stuck anywhere to collect solar energy. She did it with the help of graphene, an emerging one-atom-thick material that has tremendous capabilities when it comes to conducting electricity.

Zheng would now like to see the technology scale up to cover large areas, such as the side of a building.

Build a nuclear reactor that runs on nuclear waste

Nuclear waste is a problem. Not only do we not have a great place to store it, it’s dangerous for 100,000 years. Transatomic Power co-founder Leslie Dewan looked at reactors designed in the 1950s to power aircraft and used them to design a new reactor that can use spent nuclear material as fuel. Each reactor can use one ton of nuclear waste a year, creating just under 9 pounds of its own nuclear waste in the process.

The 1950s version was large and expensive. Dewan’s redesign outputs 30 times more power, which means it is compact enough to ship on a train. The way it is built also means there is no chance of a meltdown.

Make better robots with open source software

Until 2010, roboticists had to start from scratch when they built software for their bots, driving up cost and complexity. Then Morgan Quinley of the Open Source Robotics Foundation built ROS, open source software that is now the industry standard. Even famous bots like Baxter use ROS.

“Robots are the meeting place between electronics, software, and the real world,” he told MIT Technology Review. “They’re the way software experiences the world.”

Use fish as inspiration for wind farms

California Institute of Technology professor John Dabiri looked at wind farms and asked if there was any way to squeeze the turbines closer together. Turbulence usually creates problems, but can be overcome by spacing them out. Dabiri looked to schools of fish to find more efficient arrangements.

“We looked at an arrangement that’s been identified as optimal for fish, and we found that if we, in our computer models, arranged our wind turbines exactly in the same kind of diamond pattern that fish form, you get significant benefits in the performance of a wind farm,” Dabiri told MIT Technology Review.

Move money with less fees

When you use a credit card or PayPal, a tiny bit of what you pay is siphoned off as a fee. This adds up quick for businesses. Dwolla founder Ben Milne is pursuing a payment system that isn’t reliant on the four big financial networks that handle cash-free transactions. It’s instant and secure, and there is no fee for transactions that ring in under $10.

It’s a tough job. Dwolla has to sign an agreement with every single bank for the system to work.

“In Silicon Valley, people are looking for a silver bullet,” Milne told MIT Technology Review. “I look at it like a Midwesterner: I have an ax and I’m going to cut down a tree. You close the first customer, then the second, then the third. It’s hard work, but that’s the way you do it.”

Accelerate economic development with solar lamps

Evans Wadongo, head of sustainable development for the NGO All, grew up in rural Kenya, where he struggled to study at night by the light of a kerosene lantern. It inspired him to design a lamp made of scrap metal, readily available photovoltaic panels, batteries and LEDs. Replacing kerosene with solar power saves families about a dollar a week, which allows them to make other money-generating investments, such as buying livestock or opening a microlending service.

All has distributed 32,000 lamps to date. Wadongo plans to open 20 more manufacturing centers that will build lamps and other creative goods they dream up.

Nanotechnology in Desalination


 

201306047919620A couple of years ago a nanotube technology paper for nanotech desalination was issued by Tamsyn A. Hilder , Daniel Gordon, Shin-Ho Chung and this was the summary:

 

“Current desalination methods force seawater through a filter using energies four times larger than necessary. Throughout the desalination process salt must be removed from one side of the filter to avoid the need to apply even larger energies. “Using boron nitride nanotubes, and the same operating pressure as current desalination methods, we can achieve 100 percent salt rejection for concentrations twice that of seawater with water flowing four times faster, which means a much faster and more efficient desalination process.”

It gave the impression that this solution actually worked, but from all accounts it was still only a theory. Well now a new Nametech project co-funded by the European Commission and the University of Applied Sciences Northwestern Switzerland, is enhancing filters already used in water treatment plants with nanoparticles that do specific jobs.

drinking tap water, articles.waterdesalinationplants.com

This recent nanotechnology desalination update from Katharine Sanderson of guardian.co.uk provides us with further insight to what is the current situation with nanotechnology.

 

We’re a thirsty species. Humans can’t survive without fresh, clean, drinking water, yet we sprang to life on a planet where 97.5% of water is useless to us.

What’s left for us to drink is becoming more and more polluted by agriculture, industry and poor water-management. By 2030, 3.9 billion people (47% of the predicted population) won’t have access to clean water.

There is a tiny solution to this large problem: nanomaterials can strip water of toxic metals and dangerous organic molecules, or turn salt water into fresh water. There are also plenty of other nanotech solutions in development.

Nanotechnologies that have the best chance are ones we can integrate into existing systems,” says Mamadou Diallo, an environmental engineer at the California Institute of Technology. That means, for example, membranes enhanced with nanoparticles that can slot seamlessly into water treatment plants.

“We’re adding a wide range of nanoparticles,” says project manager Thomas Wintgens of the University of Applied Sciences Northwestern Switzerland in Muttenz. These include:

Biomagentite, an iron mineral, to get rid of chlorinated organic molecules and some toxic metals.

Silver to kill bacteria.

Nanoparticles of titanium dioxide to break down common organic contaminants such as hormones, pharmaceuticals, or manure – all they need to operate is some light to shine on them when they are in the water.

Titanium dioxide, which is already widely used in paints and sunscreens so, in principle, the technology is cheap.

Nametech is running a small pilot plant to test the membranes. Each 20cm module can process around a cubic metre of water every hour. But, like other new technologies, it needs to be proven beyond the lab.

Rob Lammertink of the University of Twente, the Netherlands, says there is interest from industry for nanotechnology water treatments, but it is still early days. He heads the nanotechnology in water group of a large consortium, NanoNextNL, and predicts that, perhaps in five or 10 years, nanotech water treatments might be used on a large scale.

Other scientists have put the conservatism of the water industry aside, and are thinking smaller to make sure people don’t go thirsty.

In South Africa, the humble teabag has inspired a way to clean water 1-litre at a time. In the mouth of an ordinary drinking bottle sits a teabag-like net that is a nanotech marvel.

Developed by Eugene Cloete at Stellenbosch University in South Africa, the inside of the biodegradable teabag is coated with thin water-soluble polymer nanofibres that have been impregnated with anti-microbial agents and spun into a fine mesh.

The material filters out most contaminants – up to 99.99% of bacteria. The “tea leaves” inside the bag are activated carbon, which can suck out heavy metals and other contaminants.

As yet the tea bag remains a prototype, the final version, intended for consumers, is still being developed by the company AquaQure. But there is already much hope that this filter could make a big difference to the lives of people who do not have easy access to clean water.

Cleaning up dirty water isn’t the only way to quench the world’s thirst. Diallo says that producing fresh water out of the world’s plentiful supply of salty water, a process called desalination, will be made more efficient and cost effective with nanotechnology.

It could be of huge benefit in countries such as his native Senegal, where over-exploitation of groundwater means that ever-deeper aquifers need to be drilled. Deeper aquifers invariably lead to more brackish water.

Desalination is expensive and needs lots of energy. Reverse osmosis, the favoured current technology, uses high pressures to pump contaminated water across a membrane. “At the moment we extract clean water from seawater – we need to extract the salt instead,” says Diallo. “We can’t do this without advanced nanomaterials.”

Water produced from the world’s cheapest desalination plants cost about 31p a cubic metre at the moment. But things could be cheaper.

Put two metal plates into salty water, for example, and apply a voltage across them, and the salt will start to separate from the liquid. The positively-charged half of the salt molecules (known as ions) gets attracted to the negatively-charged metal plate and vice versa.

Coat the metal plates with nanomaterials and cycle the voltage across them, and the salt ions can be collected and removed relatively efficiently. Nano-engineered carbon and carbon nanotubes are being examined as candidates, with the potential to cut desalination costs by 75%.

Diallo says that a capacitance device such as the one described above is at least 10 years away from being available on an industrial scale.

But more decentralised water treatment might allow nanotechnology to play a bigger role, in the developing world, for example, where large-scale water distribution centres and networks of pipes do not already exist.

Nanotech desalination and treatment devices could go straight to point of use, or be used in small-scale or emergency situations. “Maybe nanotechnology will level the playing field,” says Diallo, and give everyone a clean glass of water to drink.

Clean drinking water the world’s most precious resource is in short supply for most of the world’s population, but nanotechnology can go a long way to ensuring no one goes thirsty. Bring it on!

Do you believe nanotech desalination will be the next big thing for providing potable water for the human race?

NSF grant to develop cutting-edge nanomaterials


201306047919620(Nanowerk News) The National Science Foundation (NSF)  has awarded New York University researchers and their colleagues at the  California Institute of Technology (Caltech) a $2 million grant to develop  cutting-edge nanomaterials that hold promise for improving the manufacturing of  advanced materials, biofuels, and other industrial products.
Under the grant, the scientists will develop biomimetic  materials with revolutionary properties—these molecules will self-replicate,  evolve, and adopt three-dimensional structures a billionth of a meter in size by  combining DNA-guided self-assembly with the centuries-old art of origami  folding.
The four-year grant is part of the NSF’s Origami Design for  Integration of Self-assembling Systems for Engineering Innovation (ODISSEI)  program and includes NYU Chemistry Professors Nadrian Seeman and James Canary  and NYU Physics Professor Paul Chaikin. They will team up with Caltech’s William  A. Goddard, III and Si-ping Han.
Others involved in the project are molecular biologists John  Rossi and Lisa Scherer of City of Hope Medical Center and mathematicians Joanna  Ellis-Monaghan and Greta Pangborn of Saint Michael’s College in Vermont.
The work will build upon recent breakthroughs in the field of  structural DNA nanotechnology, which Seeman founded more than three decades ago  and is now pursued by laboratories across the globe. His creations allow him to  arrange pieces and form specific molecules with precision—similar to the way a  robotic automobile factory can be told what kind of car to make.
Previously, Seeman has created three-dimensional DNA structures,  a scientific advance bridging the molecular world to the world where we live. To  do this, he and his colleagues created DNA crystals by making synthetic  sequences of DNA that have the ability to self-assemble into a series of 3D  triangle-like motifs. The creation of the crystals was dependent on putting  “sticky ends”—small cohesive sequences on each end of the motif—that attach to  other molecules and place them in a set order and orientation. The make-up of  these sticky ends allows the motifs to attach to each other in a programmed  fashion.
Recently, the Seeman and Chaikin labs teamed up to develop  artificial structures that can self-replicate, a process that has the potential  to yield new types of materials. In the natural world, self-replication is  ubiquitous in all living entities, but artificial self-replication had  previously been elusive. Their work marked the first steps toward a general  process for self-replication of a wide variety of arbitrarily designed “seeds”.  The seeds are made from DNA tile motifs that serve as letters arranged to spell  out a particular word. The replication process preserves the letter sequence and  the shape of the seed and hence the information required to produce further  generations. Self-replication enables the evolution of molecules to optimize  particular properties via selection processes.
Under the NSF grant, the researchers will aim to take these  innovations to the next level: the creation of self-replicating 3D arrays. To do  so, the collaborators will aim to fold replicating 1D and 2D arrays into 3D  shapes in a manner similar to paper origami—a complex and delicate process.
In meeting this challenge, they will adopt tools from graph  theory and origami mathematics to develop algorithms to direct self-assembling  DNA nanostructures and their origami folds. The mathematical component of the  endeavor will be supplemented by the artistic expertise of Portland, Ore.-based  sculptor Julian Voss-Andreae, who will advise the team on issues related to  design and will use his skills to develop life-size physical models of the  nanoscopic structures the scientists are seeking to build.
The program officer at NSF responsible for monitoring this  Emerging Frontiers in Research and Innovation (EFRI) project is Paul Collopy.
Source: New York University

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Saudi Money Shaping U.S. Research


Susan Schmidt | February 11, 2013

qdots-imagescakxsy1k-8.jpgSaudi Arabia’s oil reserves are expected to run dry in fifty years. This prospect has encouraged the Saudis to go shopping for cutting-edge science that can secure the kingdom’s future—at elite American research universities.

 

King Abdullah and Saudi Aramco are spending tens of billions on technology research to make the oil last longer and develop other energy resources that future Saudi generations can someday export.

KAUST_lab

King Abdullah University of Science and Technology opened its doors in 2009 and already has lavished more than $200 million on top U.S. university scientists. Stanford, Cornell, Texas A&M, UC Berkeley, CalTech, Georgia Tech—all are awash in new millions of Saudi cash for research directed at advancing solutions for Saudi energy and water needs. The new university, known as KAUST, has similar partnerships with scientists at Peking University and Oxford.

Many American universities and their scientists, lured by research grants of as much as $25 million, have jumped at the chance to partner with KAUST. Some of those scientists do research at their universities here and spend a small part of their time in Saudi Arabia creating “mirror” labs.

The arrangement with KAUST raises novel and largely unaddressed issues for American universities. With the United States determined to become energy self-sufficient, what are the ramifications of having scientists at top university labs—many of them recipients of U.S. government research dollars—devoting their efforts to energy pursuits selected by Saudi Arabia?

KAUST funding for U.S. scientists is geared to helping the Saudis cut their own heavy oil use at home to lengthen the life of their much more lucrative exports. It’s aimed at getting more oil per well with new technology, finding new reserves and developing new methods of carbon capture for continued use of fossil fuels. American scientists are also working to develop solar technology, including solar panels that can survive sandstorms and power desalinization of the Red Sea for water and electricity.

Among the areas KAUST is not funding is research on biofuels—which compete with oil—except for work on Red Sea algae.

KAUST’s mission statement lays out a plan to rapidly become a top international institution that “will play a crucial role in the development of Saudi Arabia and the world.” KAUST’s goal is not only to find new energy sources, but to create a Silicon Valley-like commercial hub of jobs and innovation. King Abdullah provided a whopping $20 billion endowment to launch the graduate-level research institution, and named the Saudi oil minister chairman of the board of trustees. Aramco built the campus, funds current operating costs and provided administrative leadership.

“It’s an important research lab for Aramco with a university façade,” said Alyn Rockwood, one of several scientists who say they want KAUST to succeed but believe a corporate ethos is stifling academic autonomy.

Some have bridled over changes that require them to get administrative approval in spending their research funds. KAUST officials declined interview requests, but in a Science magazine story late last year that cited some of those complaints, the former Aramco executive who runs KAUST, Nadhmi al-Nasr, acknowledged that he comes from a “top-down” corporate culture and is adjusting to academia.

Scientific research at universities is a key driver of debate over how to meet global energy needs. Often of late, it is the research itself that gets debated. Dueling studies about the environmental impact of biofuels and the safety of hydraulic fracking for natural gas has spurred charges and countercharges about the role of commercial interests biasing the science, for example.

The impact of published studies is not lost on the leaders at KAUST. In fact, the top of its mission statement sets out very specific goals for getting its research published in “prestigious professional journals.” By that measure, KAUST-funded scientists have been highly successful, with stacks of prestigious journal publications and patents to their credit.

One of them is William J. Koros, a Georgia Tech professor who was awarded a $10 million research grant for his work there on hydrocarbons. “They are very generous to home universities,” he said. Koros is working on technology that would help capture impurities from natural gas. “The Middle East is loaded with natural gas. They viewed this as a world problem that intersected with their interests,” he said.

Experts in issues related to academic research funding say KAUST’s relationship with U.S. scientists is unusual, posing pitfalls as well as opportunities.

“I don’t think there is a framework for dealing with foreign governments or corporations who invest in American universities to compete,” Tufts professor Sheldon Krimsky, who has studied conflicts of interest in academic research. Where American researchers get money does not mean the science produced will be anything less than honest. But, he said, scientific inquiry is shaped by the scope of the questions asked.

James Luyten, former director of Woods Hole Oceanographic Institution, sees the creation of a specific research agenda as a problem at KAUST. KAUST awarded Woods Hole $25 million and Luyten spent three years helping set up their Red Sea research center.

“They are using their money to limit and constrain where people put their energy as research scientists,” said Luyten, something that corporate sponsors often try to achieve by carefully choosing which science to fund and which to ignore.

Luyten said he was under “enormous pressure” to devote resources to algae biofuels research, for example, but was discouraged from research on the effect of carbon emissions on Red Sea coral. “A group of us wanted to hold a symposium on climate change,” he said, but the university president rejected the idea. “We were told that was not in the interest of Saudi Arabia,” he said.

KAUST reserves the right to review studies before publication, something that is not generally done by U.S. universities, though scientists and administrators who’ve worked at KAUST say so far it has been pro forma.

American universities, faced with a shrinking pool of research dollars at home, have welcomed the Saudi partnership as a way to fund important science, including in the area of carbon capture, an issue that has global implications. Creating jobs and educating the Saudi populace is seen as vital to making theirs a stable society, something that may benefit the rest of the world, though aiding a repressive regime has drawn objections from faculty on a few U.S. campuses. To bring in foreign scientists, the Saudi king has made KAUST an oasis of modernity, where male and female students are allowed to mix.

Several prominent scientists said KAUST has the resources to have a big impact on scientific research.

“I don’t think there is any university in the world that has as advanced equipment as they have,” said Stanford solar cell researcher Mike McGeehee. He spent a month helping set up a lab at KAUST and leads Stanford’s Center for Advanced Molecular Photovoltaics, created with a $25 million KAUST grant.

Science at KAUST is directed more toward commercial application. “Things are different there. There’s a tighter connection to industry,’’ said McGeehee.

“You can’t do certain kinds of research at US universities—you can’t have industry come in and do experiments because federal dollars are paying for it, and you can’t give one company an advantage over another. But there, the king says I’m paying for it, I want [commercial] spin-offs.”

American university relationships with corporate research sponsors are a hotly debated topic, notably because of controversy over biased drug studies paid for by pharmaceutical companies. Many universities encourage professors to find corporate as well as government funders, but they keep those contractual arrangements confidential, including terms for industry access to research as well as intellectual-property arrangements. The American Association of University Professors is completing a major study on how universities should structure industry relationships.

To date, in fact, KAUST’s website has publicized its grants to a greater degree than the U.S. universities and scientists receiving them. Universities here have reported very few of the KAUST grants and contracts to the U.S. Department of Education, which maintains a public database of foreign funds to American colleges.

AAUP president Cary Nelson, who is working on the report on corporate-sponsored research, said he was not previously aware of the KAUST grants. “What you are looking at is the touchiest area. All funded research should be reviewed by faculty senate or faculty committee. It should be transparent,” he said.

Cornell University campus publications contain more information of its work with KAUST than is available from other universities, but even there administrators are circumspect about terms of Cornell’s $28 million in KAUST grants and contracts.

“It’s not public,” said Celia Szczepura, administrator of the KAUST-Cornell Center for Energy and Sustainability. As for the work Cornell does that may end up aiding the Saudi oil industry, she said: “KAUST isn’t an industry sponsor—it’s a university. What they share with Aramco and what they don’t, you’d have to ask KAUST.”

But separating the Saudi king’s new university from the kingdom’s oil industry is all but impossible. For now, Saudi Arabia’s petroleum interests have a key role in choosing what energy research is pursued by some of America’s leading scientists.

Susan Schmidt is a longtime Washington journalist and a visiting fellow with the Foundation for Defense of Democracies.

Engineers create device that can focus light into a nanoscale point (w/video)


QDOTS imagesCAKXSY1K 8(Nanowerk News) As technology advances, it tends to  shrink. From cell phones to laptops—powered by increasingly faster and tinier  processors—everything is getting thinner and sleeker. And now light beams are  getting smaller, too.
Engineers at the California Institute of Technology (Caltech)  have created a device that can focus light into a point just a few nanometers  (billionths of a meter) across—an achievement they say may lead to  next-generation applications in computing, communications, and imaging.
Because light can carry greater amounts of data more efficiently  than electrical signals traveling through copper wires, today’s technology is  increasingly based on optics. The world is already connected by thousands of  miles of optical-fiber cables that deliver email, images, and the latest video  gone viral to your laptop.
As we all produce and consume more data, computers and  communication networks must be able to handle the deluge of information.  Focusing light into tinier spaces can squeeze more data through optical fibers  and increase bandwidth. Moreover, by being able to control light at such small  scales, optical devices can also be made more compact, requiring less energy to  power them.
But focusing light to such minute scales is inherently  difficult. Once you reach sizes smaller than the wavelength of light—a few  hundred nanometers in the case of visible light—you reach what’s called the  diffraction limit, and it’s physically impossible to focus the light any  further.
But now the Caltech researchers, co-led by assistant professor  of electrical engineering Hyuck Choo, have built a new kind of waveguide—a  tunnellike device that channels light—that gets around this natural limit. The  waveguide, which is described in a recent issue of the journal Nature  Photonics (“Nanofocusing in a metal-insulator-metal gap plasmon  waveguide with a three-dimensional linear taper”), is made of amorphous  silicon dioxide—which is similar to common glass—and is covered in a thin layer  of gold. Just under two microns long, the device is a rectangular box that  tapers to a point at one end.
As light is sent through the waveguide, the photons interact  with electrons at the interface between the gold and the silicon dioxide. Those  electrons oscillate, and the oscillations propagate along the device as  waves—similarly to how vibrations of air molecules travel as sound waves.  Because the electron oscillations are directly coupled with the light, they  carry the same information and properties—and they therefore serve as a proxy  for the light.
Instead of focusing the light alone—which is impossible due to  the diffraction limit—the new device focuses these coupled electron  oscillations, called surface plasmon polaritons (SPPs). The SPPs travel through  the waveguide and are focused as they go through the pointy end.
Because the new device is built on a semiconductor chip with  standard nanofabrication techniques, says Choo, the co-lead and the  co-corresponding author of the paper, it is easy integrate with today’s  technology
Previous on-chip nanofocusing devices were only able to focus  light into a narrow line. They also were inefficient, typically focusing only a  few percent of the incident photons, with the majority absorbed and scattered as  they traveled through the devices.
With the new device, light can ultimately be focused in three  dimensions, producing a point a few nanometers across, and using half of the  light that’s sent through, Choo says. (Focusing the light into a slightly bigger  spot, 14 by 80 nanometers in size, boosts the efficiency to 70 percent). The key  feature behind the device’s focusing ability and efficiency, he says, is its  unique design and shape.
“Our new device is based on fundamental research, but we hope  it’s a good building block for many potentially revolutionary engineering  applications,” says Myung-Ki Kim, a postdoctoral scholar and the other lead  author of the paper.
This video shows the final step of the fabrication process:
For example, one application is to turn this nanofocusing device  into an efficient, high-resolution biological-imaging instrument, Kim says. A  biologist can dye specific molecules in a cell with fluorescent proteins that  glow when struck by light. Using the new device, a scientist can focus light  into the cell, causing the fluorescent proteins to shine. Because the device  concentrates light into such a small point, it can create a high-resolution map  of those dyed molecules. Light can also travel in the reverse direction through  the nanofocuser: by collecting light through the narrow point, the device turns  into a high-resolution microscope.
The device can also lead to computer hard drives that hold more  memory via heat-assisted magnetic recording. Normal hard drives consist of rows  of tiny magnets whose north and south poles lay end to end. Data is recorded by  applying a magnetic field to switch the polarity of the magnets.
Smaller magnets would allow more memory to be squeezed into a  disc of a given size. But the polarities of smaller magnets made of current  materials are unstable at room temperature, causing the magnetic poles to  spontaneously flip—and for data to be lost. Instead, more stable materials can  be used—but those require heat to record data. The heat makes the magnets more  susceptible to polarity reversals. Therefore, to write data, a laser is needed  to heat the individual magnets, allowing a surrounding magnetic field to flip  their polarities.
Today’s technology, however, can’t focus a laser into a beam  that is narrow enough to individually heat such tiny magnets. Indeed, current  lasers can only concentrate a beam to an area 300 nanometers wide, which would  heat the target magnet as well as adjacent ones—possibly spoiling other recorded  data.
Because the new device can focus light down to such small  scales, it can heat smaller magnets individually, making it possible for hard  drives to pack more magnets and therefore more memory. With current technology,  discs can’t hold more than 1 terabyte (1,000 gigabytes) per square inch. A  nanofocusing device, Choo says, can bump that to 50 terabytes per square inch.
Then there’s the myriad of data-transfer and communication  applications, the researchers say. As computing becomes increasingly reliant on  optics, devices that concentrate and control data-carrying light at the  nanoscale will be essential—and ubiquitous, says Choo, who is a member of the  Kavli Nanoscience Institute at Caltech. “Don’t be surprised if you see a similar  kind of device inside a computer you may someday buy.”
The next step is to optimize the design and to begin building  imaging instruments and sensors, Choo says. The device is versatile enough that  relatively simple modifications could allow it to be used for imaging,  computing, or communication.
Source: California Institute of Technology

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