Duke Research Blog

Following the people and events that make up the research community at Duke.

Category: Nanotech (Page 1 of 2)

Stretchable, Twistable Wires for Wearable Electronics

A new conductive “felt” carries electricity even when twisted, bent and stretched. Credit: Matthew Catenacci

The exercise-tracking power of a Fitbit may soon jump from your wrist and into your clothing.

Researchers are seeking to embed electronics such as fitness trackers and health monitors into our shirts, hats, and shoes. But no one wants stiff copper wires or silicon transistors deforming their clothing or poking into their skin.

Scientists in Benjamin Wiley’s lab at Duke have created new conductive “felt” that can be easily patterned onto fabrics to create flexible wires. The felt, composed of silver-coated copper nanowires and silicon rubber, carries electricity even when bent, stretched and twisted, over and over again.

“We wanted to create wiring that is stretchable on the body,” said Matthew Catenacci, a graduate student in Wiley’s group.

The conductive felt is made of stacks of interwoven silver-coated copper nanotubes filled with a stretchable silicone rubber (left). When stretched, felt made from more pliable rubber is more resilient to small tears and holes than felts made of stiffer rubber (middle). These tears can be seen in small cavities in the felt (right). Credit: Matthew Catenacci

To create a flexible wire, the team first sucks a solution of copper nanowires and water through a stencil, creating a stack of interwoven nanowires in the desired shape. The material is similar to the interwoven fibers that comprise fabric felt, but on a much smaller scale, said Wiley, an associate professor of chemistry at Duke.

“The way I think about the wires are like tiny sticks of uncooked spaghetti,” Wiley said. “The water passes through, and then you end up with this pile of sticks with a high porosity.”

The interwoven nanowires are heated to 300 F to melt the contacts together, and then silicone rubber is added to fill in the gaps between the wires.

To show the pliability of their new material, Catenacci patterned the nanowire felt into a variety of squiggly, snaking patterns. Stretching and twisting the wires up to 300 times did not degrade the conductivity.

The material maintains its conductivity when twisted and stretched. Credit: Matthew Catenacci

“On a larger scale you could take a whole shirt, put it over a vacuum filter, and with a stencil you could create whatever wire pattern you want,” Catenacci said. “After you add the silicone, so you will just have a patch of fabric that is able to stretch.”

Their felt is not the first conductive material that displays the agility of a gymnast. Flexible wires made of silver microflakes also exhibit this unique set of properties. But the new material has the best performance of any other material so far, and at a much lower cost.

“This material retains its conductivity after stretching better than any other material with this high of an initial conductivity. That is what separates it,” Wiley said.

Stretchable Conductive Composites from Cu-Ag Nanowire Felt,” Matthew J. Catenacci, Christopher Reyes, Mutya A. Cruz and Benjamin J. Wiley. ACS Nano, March 14, 2018. DOI: 10.1021/acsnano.8b00887

Post by Kara Manke

Farewell, Electrons: Future Electronics May Ride on New Three-in-One Particle

“Trion” may sound like the name of one of the theoretical particles blamed for mucking up operations aboard the Starship Enterprise.

But believe it or not, trions are real — and they may soon play a key role in electronic devices. Duke researchers have for the first time pinned down some of the behaviors of these one-of-a-kind particles, a first step towards putting them to work in electronics.

A carbon nanotube, shaped like a rod, is wrapped in a helical coating of polymer

Three-in-one particles called trions — carrying charge, energy and spin — zoom through special polymer-wrapped carbon nanotubes at room temperature. Credit: Yusong Bai.

Trions are what scientists call “quasiparticles,” bundles of energy, electric charge and spin that zoom around inside semiconductors.

“Trions display unique properties that you won’t be able to find in conventional particles like electrons, holes (positive charges) and excitons (electron-hole pairs that are formed when light interacts with certain materials),” said Yusong Bai, a postdoctoral scholar in the chemistry department at Duke. “Because of their unique properties, trions could be used in new electronics such as photovoltaics, photodetectors, or in spintronics.”

Usually these properties – energy, charge and spin – are carried by separate particles. For example, excitons carry the light energy that powers solar cells, and electrons or holes carry the electric charge that drives electronic devices. But trions are essentially three-in-one particles, combining these elements together into a single entity – hence the “tri” in trion.

A diagram of how a trion is formed in carbon nanotubes.

A trion is born when a particle called a polaron (top) marries an exciton (middle). Credit: Yusong Bai.

“A trion is this hybrid that involves a charge marrying an exciton to become a uniquely distinct particle,” said Michael Therien, the William R. Kenan, Jr. Professor of Chemistry at Duke. “And the reason why people are excited about trions is because they are a new way to manipulate spin, charge, and the energy of absorbed light, all simultaneously.”

Until recently, scientists hadn’t given trions much attention because they could only be found in semiconductors at extremely low temperatures – around 2 Kelvin, or -271 Celcius. A few years ago, researchers observed trions in carbon nanotubes at room temperature, opening up the potential to use them in real electronic devices.

Bai used a laser probing technique to study how trions behave in carefully engineered and highly uniform carbon nanotubes. He examined basic properties including how they are formed, how fast they move and how long they live.

He was surprised to find that under certain conditions, these unusual particles were actually quite easy to create and control.

“We found these particles are very stable in materials like carbon nanotubes, which can be used in a new generation of electronics,” Bai said. “This study is the first step in understanding how we might take advantage of their unique properties.”

The team published their results Jan. 8 in the Proceedings of the National Academy of Sciences.

Dynamics of charged excitons in electronically and morphologically homogeneous single-walled carbon nanotubes,” Yusong Bai, Jean-Hubert Olivier, George Bullard, Chaoren Liu and Michael J. Therien. Proceedings of the National Academy of Sciences, Jan. 8, 2018 (online) DOI: 10.1073/pnas.1712971115

Post by Kara Manke

Science Meets Policy, and Maybe They Even Understand Each Other!

As we’ve seen many times, when complex scientific problems like stem cells, alternative energy or mental illness meet the policy world, things can get a little messy. Scientists generally don’t know much about law and policy, and very few policymakers are conversant with the specialized dialects of the sciences.

A screenshot of SciPol’s handy news page.

Add the recent rapid emergence of autonomous vehicles, artificial intelligence and gene editing, and you can see things aren’t going to get any easier!

To try to help, Duke’s Science and Society initiative has launched an ambitious policy analysis group called SciPol that hopes to offer great insights into the intersection of scientific knowledge and policymaking. Their goal is to be a key source of non-biased, high-quality information for policymakers, academics, commercial interests, nonprofits and journalists.

“We’re really hoping to bridge the gap and make science and policy accessible,” said Andrew Pericak, a contributor and editor of the service who has a 2016 masters in environmental management from the Nicholas School.

The program also will serve as a practical training ground for students who aspire to live and work in that rarefied space between two realms, and will provide them with published work to help them land internships and jobs, said SciPol director Aubrey Incorvaia, a 2009 masters graduate of the Sanford School of Public Policy.

Aubrey Incorvaia chatted with law professor Jeff Ward (center) and Science and Society fellow Thomas Williams at the kickoff event.

SciPol launched quietly in the fall with a collection of policy development briefs focused on neuroscience, genetics and genomics. Robotics and artificial intelligence coverage began at the start of January. Nanotechnology will launch later this semester and preparations are being made for energy to come online later in the year. Nearly all topics are led by a PhD in that field.

“This might be a different type of writing than you’re used to!” Pericak told a meeting of prospective undergraduate and graduate student authors at an orientation session last week.

Some courses will be making SciPol brief writing a part of their requirements, including law professor Jeff Ward’s section on the frontier of robotics law and ethics. “We’re doing a big technology push in the law school, and this is a part of it,” Ward said.

Because the research and writing is a learning exercise, briefs are published only after a rigorous process of review and editing.

A quick glance at the latest offerings shows in-depth policy analyses of aerial drones, automated vehicles, genetically modified salmon, sports concussions and dietary supplements that claim to boost brain power.

To keep up with the latest developments, the SciPol staff maintains searches on WestLaw, the Federal Register and other sources to see where science policy is happening. “But we are probably missing some things, just because the government does so much,” Pericak said.

Post by Karl Leif Bates

When Art Tackles the Invisibly Small

Huddled in a small cinderblock room in the basement of Hudson Hall, visual artist Raewyn Turner and mechatronics engineer Brian Harris watch as Duke postdoc Nick Geitner positions a glass slide under the bulky eyepiece of an optical microscope.

To the naked eye, the slide is completely clean. But after some careful adjustments of the microscope, a field of technicolor spots splashes across the viewfinder. Each point shows light scattering off one of the thousands of silver nanoparticles spread in a thin sheet across the glass.

“It’s beautiful!” Turner said. “They look like a starry sky.”

AgAlgae_40x_Enhanced3

A field of 10-nanometer diameter silver nanoparticles (blue points) and clusters of 2-4 nanoparticles (other colored points) viewed under a dark-field hyperspectral microscope. The clear orbs are cells of live chlorella vulgaris algae. Image courtesy Nick Geitner.

Turner and Harris, New Zealand natives, have traveled halfway across the globe to meet with researchers at the Center for the Environmental Implications of Nanotechnology (CEINT). Here, they are learning all they can about nanoparticles: how scientists go about detecting these unimaginably small objects, and how these tiny bits of matter interact with humans, with the environment and with each other.

img_2842

The mesocosms, tucked deep in the Duke Forest, currently lay dormant.

The team hopes the insights they gather will inform the next phases of Steep, an ongoing project with science communicator Maryse de la Giroday which uses visual imagery to explore how humans interact with and “sense” the nanoparticles that are increasingly being used in our electronics, food, medicines, and even clothing.

“The general public, including ourselves, we don’t know anything about nanoparticles. We don’t understand them, we don’t know how to sense them, we don’t know where they are,” Turner said. “What we are trying to do is see how scientists sense nanoparticles, how they take data about them and translate it into sensory data.”

Duke Professor and CEINT member Mark Wiesner, who is Geitner’s postdoctoral advisor, serves as a scientific advisor on the project.

“Imagery is a challenge when talking about something that is too small to see,” Wiesner said. “Our mesocosm work provides an opportunity to visualize how were are investigating the interactions of nanomaterials with living systems, and our microscopy work provides some useful, if not beautiful images. But Raewyn has been brilliant in finding metaphors, cultural references, and accompanying images to get points across.”

img_2872

Graduate student Amalia Turner describes how she uses the dark-field microscope to characterize gold nanoparticles in soil. From left: Amalia Turner, Nick Geitner, Raewyn Turner, and Brian Harris.

On Tuesday, Geitner led the pair on a soggy tour of the mesocosms, 30 miniature coastal ecosystems tucked into the Duke Forest where researchers are finding out where nanoparticles go when released into the environment. After that, the group retreated to the relative warmth of the laboratory to peek at the particles under a microscope.

Even at 400 times magnification, the silver nanoparticles on the slide can’t really be “seen” in any detail, Geitner explained.

“It is sort of like looking at the stars,” Geitner said. “You can’t tell what is a big star and what is a small star because they are so far away, you just get that point of light.”

But the image still contains loads of information, Geitner added, because each particle scatters a different color of light depending on its size and shape: particles on their own shine a cool blue, while particles that have joined together in clusters appear green, orange or red.

During the week, Harris and Turner saw a number of other techniques for studying nanoparticles, including scanning electron microscopes and molecular dynamics simulations.

steepwashing-cake-copy-23

An image from the Steep collection, which uses visual imagery to explore how humans interact with the increasingly abundant gold nanoparticles in our environment. Credit: Raewyn Turner and Brian Harris.

“What we have found really, really interesting is that the nanoparticles have different properties,” Turner said. “Each type of nanoparticle is different to each other one, and it also depends on which environment you put them into, just like how a human will behave in different environments in different ways.”

Geitner says the experience has been illuminating for him, too. “I have never in my life thought of nanoparticles from this perspective before,” Geitner said. “A lot of their questions are about really, what is the difference when you get down to atoms, molecules, nanoparticles? They are all really, really small, but what does small mean?”

Kara J. Manke, PhD

Post by Kara Manke

Girls Get An Eye-Opening Introduction to Photonics

14711502_10153733048287100_3205727043350847171_o

Demonstration of the Relationship between Solar Power and Hydrogen Fuel. Image courtesy of DukeEngineering.

Last week I attended the “Exploring Light Technologies” open house hosted by the Fitzpatrick Institute for Photonics, held to honor International “Introduce a Girl to Photonics” Week. It was amazing!

I was particularly enraptured by a MEDx Wireless Technology presentation and demonstration titled “Using Light to Monitor Health and View Health Information.” There were three “stations” with a presenter at each station.

At the first station, the presenter, Julie, discussed how wearable technologies are used in optical heart rate monitoring. For example, a finger pulse oximeter uses light to measure blood oxygen levels and heart rates, and fitness trackers typically contain LED lights in the band. These lights shine into the skin and the devices use algorithms to read the amount of light scattered by the flow of blood, thus measuring heart rate.

At the second station, the presenter, Jackie, spoke about head-mounted displays and their uses. The Google Glass helped inspire the creation of the Microsoft Hololens, a new holographic piece of technology resembling a hybrid of laboratory goggles and a helmet. According to Jackie, the Microsoft Hololens “uses light to generate 3D objects we can see in our environment.”

14589884_10153733048602100_2715427782090593871_o

Using the Microsoft Hololens. Image courtesy of DukeEngineering.

After viewing a video on how the holographic technology worked, I put on the Microsoft Hololens at the demonstration station. The team had set up 3D images of a cat, a dog and a chimpanzee. “Focus the white point of light on the object and make an L-shape with your fingers,” directed Eric, the overseer. “Snap to make the objects move.” With the heavy Hololens pressing down on my nose, I did as he directed. Moving my head moved the point of light. Using either hand to snap made the dog bark, the cat meow and lick its paws, and the chimpanzee eat. Even more interesting was the fact that I could move around the animals and see every angle, even when the objects were in motion. Throughout the day, I saw visitors of all ages with big smiles on their faces, patting and “snapping” at the air.

Applications of the Microsoft Hololens are promising. In the medical field, they can be used to display patient health information or electronic health records in one’s line of sight. In health education, students can view displays of interactive 3D anatomical animations. Architects can use the Hololens to explore buildings. “Imagine learning about Rome in the classroom. Suddenly, you can actually be in Rome, see the architecture, and explore the streets,” Jackie said. “[The Microsoft Hololens] deepens the educational experience.”

14707854_10153733048632100_7506613834348839624_o

Tour of the Facilities. Image courtesy of DukeEngineering.

Throughout the day, I oo-ed and aw-ed at the three floors-worth of research presentations lining the walls. Interesting questions were posed on easy-to-comprehend posters, even for a non-engineer such as myself. The event organizers truly did make sure that all visitors would find at least one presentation to pique their interest. There were photonic displays and demonstrations with topics ranging from art to medicine to photography to energy conservation…you get my point.

Truly an eye-opening experience!

Post by Meg Shiehmeg_shieh_100hed

SiNON Overcomes Barriers to Win Grand Prize

In order to win Duke’s 16th annual Start-Up Challenge, Afreen Allam only had to cross the blood-brain barrier.

IMG_3675

Entrepreneur, angel investor, and Duke parent Magdalena Yesil opening the event.

Amongst a pool of entrepreneurs selling raw desserts, footwear, and online education programs, her patented neurological treatment impressed the judges enough to earn her the Wickett Family Grand Prize.

The Start-Up Challenge is a year-long entrepreneurship competition with an entry pool of over 100 student teams. Throughout the year, participants get weeded out, down to the final nine teams. The Grand Finale was held in the Fuqua School of Business on Sept. 30.

Finalists were given four minutes to pitch their idea in the hopes of winning $50,000. And for Ms. Allam, that dream came true.

Her company, SiNON, will use the prize money to continue developing her product, a patented nanoparticle that encapsulates drugs to be delivered to the brain. Her research began in her third year as an undergraduate student at one of the Indian Institutes of Technology (IITs) that was affiliated with the Massachusetts Institute of Technology. She delved into chemistry research, developing technologies with carbon nanotubes with the intention of creating an alternative to chemotherapy to battle cancer. She was encouraged to create a patent for her work, a process she initially didn’t know anything about but underwent anyway, receiving it about a year and a half ago.

Afreen Allam (holding giant check) with her friends, family and $50,000 in winnings.

Now a student at Fuqua, the direction of her research changed last summer, when Ms. Allam began focusing more on neurological diseases after discovering that her nanoparticle was able to cross the blood-brain barrier, something only 2 percent of drugs can do. Her current product, SiNON, works to increase the effectiveness of neurological treatments, as well as reducing associated side effects.

She said the funding from the Start-Up Challenge will help her company conduct feasibility studies to allow her to approach biotech and pharmaceutical companies.

Bringing a Lot of Energy to Research

By Karl Leif Bates

The Duke Energy Initiative‘s annual research collaboration workshop on May 5 was an update on how the campus-wide alliance of more than 130 faculty has been pursuing its goals of making energy  “accessible, affordable, reliable and clean.” In short, they’ve been busy!

energy posters

Energetic discussion swirled around research posters from graduate student projects and Bass Connections. (Photo: Margaret Lillard)

At the afternoon session in Gross Hall, David Mitzi, professor of mechanical engineering and materials science, led a panel of five-minute updates on energy materials including engineered microbes, computational modeling of materials, solar cells built on plastic rather than glass, and a nanomaterial-based sheet of material that would combine photovoltaics with storage on a single film.

Kyle Bradbury, managing director of the new Energy Data Analytics Lab that works with the ‘big data’ folks at iiD and the social scientists at SSRI, led a panel on the lab’s latest projects. As smart meters and Internet-enabled appliances enter the market, energy analysts will be flooded with new data, Bradbury explained. There should be great potential to improve efficiency and provide customers with useful real-time feedback, but first the torrent of information has to be corralled and analyzed.

energy panel

Kyle Bradbury (standing) moderated a data analytics panel with Leslie Collins and Matt Harding (right).

For one example of what big energy data might do, Bradbury and Electrical and Computer Engineering professor Leslie Collins (his former advisor) have done a pilot study to see if computers could be taught to  pick out roof-top solar arrays in satellite photos.  Nobody actually knows how many arrays there are or how much power they’re producing, Collins said. But without too much fussing around, their first visual search algorithm spotted 92 percent of the arrays correctly in some hand-picked images of California neighborhoods. Ramped up and tweaked, such an automated search could begin to identify just how much residential solar there is, where it is, and roughly how much energy it’s producing.

The third group of researchers, moderated by Energy Initiative associate Daniel Raimi, is working on energy markets and policy, including energy systems modeling and the regulation of green house gasses through the Clean Air Act.

Energy Initiative director Richard Newell said there were 1,400 Duke students enrolled in energy-related courses this year. A first round of six seed-funded research projects was completed and seven new projects have been selected. Eight Bass Connections teams in the energy theme were very productive as well, examining smart grids, solar energy and household energy conservation with teams of undergraduates, graduate students and faculty.

Copper Nanowires Now Match Performance of Leading Competitor

Images of the first and last stages (intermediate photo excluded) of the copper nanowire growth as seen through a transmission electron microscope. Interestingly, though not visible here, the nanowires are pink. (Photo: Shengrong Ye)

Images of the first and last stages of the copper nanowire growth as seen through a transmission electron microscope. Interestingly, though not visible here, the nanowires are pink. (Photo: Shengrong Ye)

 

By Erin Weeks

Copper nanowires are one step closer to becoming a low-cost substitute for the transparent conductor in solar cells, organic LEDs and flexible, electronic touch screens. A team at Duke has succeeded in making transparent conductors from copper nanowires that are only 1% less transparent than the conventional material, indium-tin oxide (ITO).

Copper is 1000 times more abundant and 100 times cheaper than indium, the main ingredient in ITO, but for years copper nanowires have lagged behind in terms of transmittance.

Assistant chemistry professor Benjamin Wiley’s lab has fixed that — simply by changing the aspect ratio, or the proportion of length to diameter, of the nanowires. The findings were reported recently in the journal Chemical Communications.

“We finally have something competitive with ITO in terms of performance, and we got there by increasing the nanowire aspect ratio,” Wiley said.

Using a special growth solution, Wiley’s lab can “sprout” the nanowires in under half an hour and at normal atmospheric pressure. Further tweaking the synthesis, the team was able to prompt the nanowires to grow long and uniform in diameter, instead of tapered and baseball bat-shaped, which have lower aspect ratios.

The paper also includes the images of copper nanowire growth as observed in real time, the first time such observations have been published.

Still, at least one kink remains before the nanowire technology will be attractive for commercial production. The copper nanowires are susceptible to corrosive oxidation, which Wiley’s team has tried to remedy by coating the nanowires with materials like nickel. Unfortunately, a nickel coating reduces the transparency of the nanowire films.

“So now we’re trying to figure out ways to protect the nanowires without decreasing the performance,” Wiley said. “We’re focused on getting the same performance, but having more stability.”

Citation: “A rapid synthesis of high aspect ratio copper nanowires for high-performance transparent conducting films.” Shengrong Ye, Aaron Rathmell, et al. Chemical Communications, March 11, 2014. DOI:10.1039/c3cc48561g.

Duke Labs Produce 2 Intel Talent Search Finalists

By Karl Leif Bates

Two North Carolina high school seniors who worked on their research projects in Duke University labs are among 40 students recently named finalists of the Intel Science Talent Search 2014.

Alec Arshavsky is a senior at East Chapel Hill  High School

Alec Arshavsky is a senior at East Chapel Hill High School

Alec Arshavsky, 17, of East Chapel Hill High School is being recognized for his project “Automatic Characterization of Donor Tissue for Corneal Transplantation Surgery.”

Arshavsky worked in the Duke lab of assistant professor of ophthalmology and biomedical engineering Sina Farsiu, developing an algorithm that automates the process of making precise measurements of a donor cornea for transplant. These measurements are currently being done laboriously by hand, and they ensure that the donor eye is healthy and will be compatible with a recipient’s anatomy and not change their vision too much.

Arshavsky spent two years working on his project, first learning the mathematical framework of image processing and then applying it to automate the process of analyzing corneal images from optical coherence tomography. His algorithm is currently being used in clinical trials. Arshavsky said he will pursue engineering in college but hasn’t chosen his school yet. Alec’s dad, Vadim Arshavsky, is a professor of ophthalmology and pharmacology at Duke.

Parth Thakker recently displayed a poster of his Duke research.

Parth Thakker recently displayed a poster of his Duke research.

Parth Thakker, 17, of the North Carolina School of Science and Mathematics in Durham, did his work, “Design, Assembly, and Optimization of Novel ZnxSeAgy Biocompatible Quantum Dot Sensitized Solar Cells” in the lab of Nico Hotz, an assistant professor of Mechanical Engineering and Materials Science at Duke.

The Hotz group has been working on quantum dots for solar collection that don’t rely on toxic cadmium and lead, making them safe for skin contact. Thakker, who’s from Charlotte, said there might be an application for a wearable device like Google Glass that would benefit from a little safe solar power.

Thakker worked on his project over three months last summer, making some winning suggestions about counter-electrodes and new ways of depositing quantum dots on a substrate, “but it’s very much a group project,” he said. Thakker, who is also the student body president at NCSSM, will be headed to Harvard in the Fall, possibly to study chemistry. (He also gives a pretty good TV interview.)

March 6-12, Arshavsky, Thakker and the other 38 finalists will travel to Washington, D.C. for a week-long event to pick the Intel Science Talent Search winners. They’ll undergo a rigorous judging process not only on their own work, but also covering general problem-solving and scientific knowledge. “They want to see how you think,” Arshavsky said. The students will also get a chance to interact with leading scientists and national leaders and will display their research for the public at the National Geographic Society.

The top 10 winners will be announced at a black-tie, invite-only gala awards ceremony at the National Building Museum on March 11, 2014.

Alec presenting his work at the 2013 Annual meeting of the Association for Research in Vision and Ophthalmology in Seattle.

Alec presenting his work at the 2013 Annual meeting of the Association for Research in Vision and Ophthalmology in Seattle.

The prestigious contest awards $630,000 in prizes this year, with the first-place winner receiving $100,000 from the Intel Foundation. Many past winners have gone on to achieve great things, including eight Nobel Prizes, two Fields Medals, five National Medals of Science, 11 MacArthur Foundation Fellowships and an Academy Award for Best Actress (that would be Natalie Portman).

The following week, Arshavsky will be off to Beijing to present his work again, this time one of four students selected as winners of the North Carolina International Science Challenge.

Reading between the lines of light

By Ashley Yeager

Harry Potter's invisibility cloak is not exactly what scientists have in mind for their light tricks. Credit: Warner Brothers.

The way we understand light is largely based on how we see it. To our eyes, light is like a stream of particles.

Scientists usually study these particle streams by measuring their wavelengths and how they interact with objects. But over the last decade, researchers have begun to realize that light particles can interact with objects within wavelengths too.

Now, scientists are looking inside wavelengths to control and manipulate light, which is transforming the traditional field of optics, according to Duke engineer David Smith and his colleagues.

They describe the changes to the field of optics in a review article appearing online Aug. 2 in Science, and they describe how, at a tenth or even a hundredth of the wavelength of visible light, the classic picture of how we see breaks down.

In this regime, streams of light particles can bend away from an object, essentially tricking the eye into thinking the object is not there. As a result, scientists can no longer think of light in terms of particle streams. Instead, they must think of it as a manipulation of electric and magnetic field lines.

Thinking of light this way, Smith and other scientists are beginning to understand how they can hide one object within another and even harvest energy. The new understanding “will be the design tool of choice” as scientists continue to play with the forces between electrically charged particles, the authors argue.

Citation:

“Transformation Optics and Subwavelength Control of Light.” Pendry, J., et. al. 2012. Science 337: 549-552.
DOI: 10.1126/science.1220600

Page 1 of 2

Powered by WordPress & Theme by Anders Norén