David Kirkpatrick

May 3, 2010

Speeding up data communications …

through nano-photonics.

The release:

An Optical Traffic Cop for Rapid Communication
Monday, May 3, 2010

TAU develops fiber optics technology to replace semi-conductors

It looks like a piece of gel that slips into the sole of your sneaker, but it’s a new nano-based technology that can make computers and the Internet hundreds of times faster — a communications technology “enabler” that may be in use only five or ten years in the future, currently being created by Dr. Koby Scheuer of Tel Aviv University’s School of Electrical Engineering.

Dr. Scheuer has developed a new plastic-based technology for the nano-photonics market, which manufactures optical devices and components. Reported in the journal Optics Express, his plastic-based “filter” is made from nanometer-sized grooves embedded into the plastic. When used in fiber optics cable switches, this new device will make our communication devices smaller, more flexible and more powerful, he says.

“Once Americans have a fiber optics cable coming into every home, all communication will go through it — telephone, cable TV, the Internet. But to avoid bottlenecks of information, we need to separate the information coming through into different channels. Our polymeric devices can do that in the optical domain — at a speed, quality and cost that the semi-conductor industry can’t even imagine,” Dr. Scheuer says.

Filtering the noise from the information

Every optical device used in today’s communication tools has a filter. Whether it’s the drive reader in your MacBook or the cable that brings cheap long-distance phone calls to your phone, each system uses filters to clean up the signal and interpret the different messages. In the next decade, fiber optic cables that now run from city to city will feed directly into every individual home. When that technology comes to light, the new plastic-based switches could revolutionize the way we communicate.

“Right now, we could transmit all of the written text of the world though a single fiber in a fiber optics cable in just a few seconds,” says Dr. Scheuer. “But in order to handle these massive amounts of communication data, we need filters to make sense of the incoming information. Ours uses a plastic-based switch, replacing hard-to-fabricate and expensive semi-conductors.”

Semi-conductors, grown on crystals in sterile labs and processed in special ovens, take days and sometimes months to manufacture. They are delicate and inflexible as well, Dr. Scheuer explains. “Our plastic polymer switches come in an easy-to-work-with liquid solution. Using a method called ‘stamping,’ almost any laboratory can make optical devices out of the silicon rubber mold we’ve developed.”

The silicon rubber mold is scored with nano-sized grooves, invisible to the eye and each less than a millionth of a meter in width. A plastic solution can be poured over the mold to replicate the optical switch in minutes. When in place in a fiber-optic network, the grooves on the switch modulate light coming in through the cables, and the data is filtered and encoded into usable information.

One word of advice: “Plastics”

His biggest hurdle, says Dr. Scheuer, is in convincing the communications industry that polymers are stable materials.

“There is a lot of prejudice in this industry against plastics. But this approach could take us to a new level of communication,” the researcher says. He also notes that the process is not much different from the way that mass numbers of DVDs are produced in a factory — except Dr. Scheuer works on a nano, not a “giant” micro, scale.

His device can also be used in the gyros of planes, ships and rockets; inserted into cell phones; and made a part of flexible virtual reality gloves so doctors could “operate” on computer networks over large distances.

August 16, 2009

More cloaking news

Filed under: Science — Tags: , , , , — David Kirkpatrick @ 11:03 pm

This isn’t really on my typical topic of invisibility cloaks, but it is a very interesting cloaking technology.

The release:

A new cloaking method

This is not a ‘Star Trek’ or ‘Harry Potter’ story

IMAGE: Graeme Milton, a distinguished professor of mathematics at the University of Utah, is the senior author of two newly published studies outlining the numerical and theoretical basis for a new…

Click here for more information. 

SALT LAKE CITY, Aug. 17, 2009 – University of Utah mathematicians developed a new cloaking method, and it’s unlikely to lead to invisibility cloaks like those used by Harry Potter or Romulan spaceships in “Star Trek.” Instead, the new method someday might shield submarines from sonar, planes from radar, buildings from earthquakes, and oil rigs and coastal structures from tsunamis.

“We have shown that it is numerically possible to cloak objects of any shape that lie outside the cloaking devices, not just from single-frequency waves, but from actual pulses generated by a multi-frequency source,” says Graeme Milton, senior author of the research and a distinguished professor of mathematics at the University of Utah.

“It’s a brand new method of cloaking,” Milton adds. “It is two-dimensional, but we believe it can be extended easily to three dimensions, meaning real objects could be cloaked. It’s called active cloaking, which means it uses devices that actively generate electromagnetic fields rather than being composed of ‘metamaterials’ [exotic metallic substances] that passively shield objects from passing electromagnetic waves.”

Milton says his previous research involved “just cloaking clusters of small particles, but now we are able to cloak larger objects.”

IMAGE: These images are from animated computer simulations of a new method — developed by University of Utah mathematicians — for cloaking objects from waves of all sorts. While the new…

Click here for more information. 

For example, radar microwaves have wavelengths of about four inches, so Milton says the study shows it is possible to use the method to cloak from radar something 10 times wider, or 40 inches. That raises hope for cloaking larger objects. So far, the largest object cloaked from microwaves in actual experiments was an inch-wide copper cylinder.

A study demonstrating the mathematical feasibility of the new cloaking technique – active, broadband, exterior cloaking – was published online today in the journal Optics Express. A related paper was published online Aug. 14 in Physical Review Letters.

Milton conducted the studies with Fernando Guevara Vasquez and Daniel Onofrei, both of whom are assistant professors-lecturers in mathematics. The research was funded by the National Science Foundation and the University of Utah.

Cloaking: From Science Fiction to Science

Cloaking involves making an object partly or completely invisible to incoming waves – sound waves, sea waves, and seismic waves, but usually electromagnetic waves such as visible light, microwaves, infrared light, radio and TV waves.

Cloaking things from visible light long has been a staple of science fiction, from invisible Romulan Bird of Prey warships in “Star Trek” to cloaking devices in books, games, films and shows like “Harry Potter,” “Halo,” “Predator,” and “Stargate.”

In recent years, scientists devised and tested various cloaking schemes. They acknowledge practical optical cloaking for invisibility is many years away. Experiments so far have been limited to certain wavelengths such as microwaves and infrared light, and every method tried so far has limitations.

Compared with passive cloaking by metamaterials, the new method – which involves generating waves to protect or cloak an object from other waves – can cloak from a broader band of wavelengths, Milton says.

“The problem with metamaterials is that their behavior depends strongly on the frequency you are trying to cloak from,” he adds. “So it is difficult to obtain broadband cloaking. Maybe you’d be invisible to red light, but people would see you in blue light.”

Most previous research used interior cloaking, where the cloaking device envelops the cloaked object. Milton says the new method “is the first active, exterior cloaking” technique: cloaking devices emit signals and sit outside the cloaked object.

Videos Simulate How Cloaking Method Works

The new studies are numerical and theoretical, and show how the cloaking method can work. “The research simulates on a computer what you should see in an experiment,” Milton says. “We just do the math and hope other people do the experiments.”

The Physical Review Letters study demonstrates the new cloaking method at a single frequency of electromagnetic waves, while the Optics Express paper demonstrates how it can work broadband, or at a wide range of frequencies.

In Optics Express, the mathematicians demonstrate that three cloaking devices together create a “quiet zone” so that “objects placed within this region are virtually invisible” to incoming waves. Guevara Vasquez created short videos of mathematical simulations showing a pulse of electromagnetic or sound waves rolling past an object:

 

     

  • In one video, with the kite-shaped object uncloaked, the wave clearly interacts with the object, creating expanding, circular ripples like when a rock is thrown in a pond. 

     

  • In the second video, the object is surrounded by three point-like cloaking devices, each of which emits waves that only propagate a short distance. Those points and their emissions resemble purple sea urchins. As the passing waves roll by the cloaking devices, waves emitted by those devices interfere with the passing waves. As a result, the passing waves do not hit the cloaked object and there are no ripples.

 

Milton says the cloaking devices cause “destructive interference,” which occurs when two pebbles are thrown in a pond. In places where wave crests meet, the waves add up and the crests are taller. Where troughs meet, the troughs are deeper. But where crests cross troughs, the water is still because they cancel each other out.

The principle, applied to sound waves, is “sort of like noise cancelation devices you get with headphones in airplanes if you travel first class,” Milton says.

Protecting from Destructive Seismic and Tsunami Waves

“We proved mathematically that this method works when the wavelength of incoming electromagnetic radiation is large compared with the objects being cloaked, meaning it can cloak very small objects,” Milton says. “It also can cloak larger objects.”

Because visible light has tiny wavelengths, only microscopic objects could be made invisible by the new method.

“The cloaking device would have to generate fields that have very small wavelengths,” Milton says. “It is very difficult to build antennas the size of light waves. We’re so far from cloaking real-sized objects to visible light that it’s incredible.”

But imagine incoming waves as water waves, and envision breakwater cloaking devices that would generate waves to create a quiet zone that would protect oil rigs or specific coastal structures against incoming tsunami waves. Or imagine cloaking devices around buildings to generate vibrations to neutralize incoming seismic waves.

“Our method may have application to water waves, sound and microwaves [radar],” including shielding submarines and planes from sonar and radar, respectively, and protecting structures from seismic waves during earthquakes and water waves during tsunamis, Milton says. All those waves have wavelengths much larger than those of visible light, so the possible applications should be easier to develop.

“It would be wonderful if you could cloak buildings against earthquakes,” Milton says. “That’s on the borderline of what’s possible.”

The new method’s main disadvantage “is that it appears you must know in advance everything about the incoming wave,” including when the pulse begins, and the frequencies and amplitudes of the waves within the pulse, Milton says. That might require placement of numerous sensors to detect incoming seismic waves or tsunamis.

“Even though cloaking from light is probably impossible, it’s a fascinating subject, and there is beautiful mathematics behind it,” Milton says. “The whole area has exploded. So even if it’s not going to result in a ‘Harry Potter’ cloak, it will have spinoffs in other directions,” not only in protecting objects from waves of various sorts, but “for building new types of antennas, being able to see things on a molecular scale. It’s sort of a renaissance in classical science, with new ideas popping up all the time.”

 

###

 

A video showing an object uncloaked and cloaked as a wave passes may be seen and downloaded from http://vimeo.com/6092319 or as separate videos from http://vimeo.com/5406253 (no cloaking) and http://vimeo.com/5406236 (with cloaking).

University of Utah Public Relations

December 18, 2008

LED lighting news, part two

Okay, I’ve already posted one release on this very bit of news, but this one is a bit different — and it comes with pictures! So there you go.

It goes without saying, I’ve really been looking forward to cost-effective LED lighting for the home.

The release:

Researchers lay out vision for lighting ‘revolution’

LEDs and smart lighting could save trillions of dollars, spark global innovation

IMAGE: If all of the world’s light bulbs were replaced with energy-efficient LEDs for a period of 10 years, researchers say it would reduce global oil consumption by 962 million barrels,…

Click here for more information. 

Troy, N.Y. – A “revolution” in the way we illuminate our world is imminent, according to a paper published this week by two professors at Rensselaer Polytechnic Institute.

Innovations in photonics and solid state lighting will lead to trillions of dollars in cost savings, along with a massive reduction in the amount of energy required to light homes and businesses around the globe, the researchers forecast.

A new generation of lighting devices based on light-emitting diodes (LEDs) will supplant the common light bulb in coming years, the paper suggests. In addition to the environmental and cost benefits of LEDs, the technology is expected to enable a wide range of advances in areas as diverse as healthcare, transportation systems, digital displays, and computer networking.

“What the transistor meant to the development of electronics, the LED means to the field of photonics. This core device has the potential to revolutionize how we use light,” wrote co-authors E. Fred Schubert and Jong Kyu Kim.

IMAGE: If all of the world’s light bulbs were replaced with energy-efficient LEDs for a period of 10 years, researchers say it would reduce global oil consumption by 962 million barrels,…

Click here for more information. 

Schubert is the Wellfleet Senior Constellation Professor of Future Chips at Rensselaer, and heads the university’s National Science Foundation-funded Smart Lighting Center. Kim is a research assistant professor of electrical, computer, and systems engineering. The paper, titled “Transcending the replacement paradigm of solid-state lighting,” will be published in the Dec. 22, 2008 issue of Optics Express.

To read the full paper, visit: http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-16-26-21835.

Researchers are able to control every aspect of light generated by LEDs, allowing the light sources to be tweaked and optimized for nearly any situation, Schubert and Kim said. In general LEDs will require 20 times less power than today’s conventional light bulbs, and five times less power than “green” compact fluorescent bulbs.

If all of the world’s light bulbs were replaced with LEDs for a period of 10 years, Schubert and Kim estimate the following benefits would be realized:

 

  • Total energy consumption would be reduced by 1,929.84 joules
  • Electrical energy consumption would be reduced by terawatt hours
  • Financial savings of $1.83 trillion
  • Carbon dioxide emissions would be reduced by 10.68 gigatons
  • Crude oil consumption would be reduced by 962 million barrels
  • The number of required global power plants would be reduced by 280

 

With all of the promise and potential of LEDs, Schubert and Kim said it is important not to pigeonhole or dismiss smart lighting technology as a mere replacement for conventional light bulbs. The paper is a call to arms for scientists and engineers, and stresses that advances in photonics will position solid state lighting as a catalyst for unexpected, currently unimaginable technological advances.

“Deployed on a large scale, LEDs have the potential to tremendously reduce pollution, save energy, save financial resources, and add new and unprecedented functionalities to photonic devices. These factors make photonics what could be termed a benevolent tsunami, an irresistible wave, a solution to many global challenges currently faced by humanity and will be facing even more in the years to come,” the researchers wrote. “Transcending the replacement paradigm will open up a new chapter in photonics: Smart lighting sources that are controllable, tunable, intelligent, and communicative.”

Possible smart lighting applications include rapid biological cell identification, interactive roadways, boosting plant growth, and better supporting human circadian rhythms to reduce an individual’s dependency on sleep-inducing drugs or reduce the risk of certain types of cancer.

 

###

 

In October, Rensselaer announced its new Smart Lighting Research Center, in partnership with Boston University and the University of New Mexico, and funded by an $18.5 million, five-year award from the NSF Generation Three Engineering Research Center Program. The three primary research thrusts of the center are developing novel materials, device technology, and systems applications to further the understanding and proliferation of smart lighting technologies.

For more information on the Smart Lighting Center, visit: smartlighting.rpi.edu.

To read the news release announcing the Smart Lighting Center, visit: http://news.rpi.edu/update.do?artcenterkey=2503.

December 17, 2008

LED lighting news

Filed under: Science — Tags: , , , — David Kirkpatrick @ 1:46 am

One of my favorite emerging technologies — LED lighting for the home.

The release:

The Green (and blue, red, and white) lights of the future

Special energy issue of Optics Express describes ‘coming revolution’ in LED lighting

WASHINGTON, Dec. 17– A revolution in energy-efficient, environmentally-sound, and powerfully-flexible lighting is coming to businesses and homes, according to a paper in latest special energy issue of Optics Express, the Optical Society’s (OSA) open-access journal.

The paper envisions the future of lighting — a future with widespread use of light emitting diodes (LEDs), which offer a number of obvious and subtle advantages over traditional light bulbs.

“We are at the verge of a revolution,” says the paper’s senior author E. Fred Schubert, a professor of electrical engineering and physics at Rensselaer Polytechnic Institute in Troy, NY. “There are tremendous opportunities that open up with LED lighting.”

LEDs are more rugged, resembling something closer to hard plastic than thin glass. They are also more environmentally sound, since their manufacture does not require toxic substances such as mercury.

As an alternative to the traditional incandescent light bulb, LED lights provide significant energy savings. They can be 2,000 percent more efficient than conventional light bulbs and 500 percent more efficient than compact fluorescent bulbs. Schubert predicts that widespread use of LEDs over the course of 10 years would save more than $1 trillion in energy costs, eliminate the need for nearly a billion barrels of oil over 10 years, and lead to a substantial reduction in emissions of carbon dioxide, the most common greenhouse gas.

All of these advantages make LEDs a good replacement light source, says Schubert, adding that this is why there has been a tremendous recent expansion of the LED industry, which is growing by double-digit rates. However, he adds, the true potential of LED lighting lies in their ability to transform — rather than simply replace — lighting technology.

“Replacement is fine,” says Schubert. “But we must look beyond the replacement paradigm to see the true benefits of LED lights.” Schubert envisions a day when light switches give way to light switchboards that control not only the brightness of a light, but its color temperature and hue. Light spectra could be custom-tailored for all wavelengths, accurately matching the sun’s light qualities and vary these characteristics according to the time of day, for instance. This could revolutionize indoor agriculture and help night-shift workers and people who are jet-lagged. The use of polarized light from LEDs could also improve computer displays and lower the glare from car headlights.

In his article, Schubert lays out how such future, “smart” light sources, can harness the huge potential of LEDs.

 

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Paper: “Transcending the Replacement Paradigm of Solid-State Lighting,” E. Fred Schubert and Jong Kyu Kim, Optics Express, Vol. 16, Issue 6, December 22, 2008, Focus Issue on Solar Energy edited by Alan Kost, University of Arizona.

About OSA
Uniting more than 70,000 professionals from 134 countries, the Optical Society (OSA) brings together the global optics community through its programs and initiatives. Since 1916 OSA has worked to advance the common interests of the field, providing educational resources to the scientists, engineers and business leaders who work in the field by promoting the science of light and the advanced technologies made possible by optics and photonics. OSA publications, events, technical groups and programs foster optics knowledge and scientific collaboration among all those with an interest in optics and photonics. For more information, visit www.osa.org.

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