New Material Makes the Most of Light
RENEE MONTAGNE, host:
Okay, so the following story is no reflection on you, literally in this case. Scientists in New York have used nanotechnology to create an optical coating that virtually eliminates the reflection when you shine a light on it. The scientists say the new material could lead to all kinds of improvements in optical devices, from brighter lights to more efficient solar panels.
NPR's Joe Palca has more.
JOE PALCA: It may have happened while you weren't paying attention, but in the past few decades the world of communication has been moving from electricity to light.
Mr. JOHN BALLATO (Director of Center for Optical Materials, Clemson University): Every time you pick up the phone, or send an e-mail, or log on to the Internet that information is being carried as light through a thin-glass optical fiber.
PALCA: That's John Ballato. He's director of the Center for Optical Materials at Clemson University in South Carolina. There are several reasons for this shift from electrons to photons. One is that you can pack more information into a fiber optic cable than you can into a simple wire. And with the gobs of data being transmitted over the Internet, that becomes a big advantage. But Ballato says working with light presents a new set of problems.
Mr. BALLATO: The big problem turns out to be that the light doesn't always get where we want it to go because it bounces off of something.
PALCA: Ballato says it's like the problem you get when you're trying to record your voice in an echoey room. If the sound waves bounce around a little, the information is still clear. But if they bounce around too much, you've got a problem.
Mr. BALLATO: So if we can find ways of taking materials, putting something on them so that it reduces the desire of the material to reflect it, then you saved yourself some of that light and you have major job a lot easier.
PALCA: And at Rensselaer Polytechnic Institute in Troy, New York, scientists think they have found just what's needed to make the job easier. They deposit a thin film of silicon dioxide nanorods on a material and - presto! - they can reduce the amount of light that bounces away from that material practically to zero. They report their results in the March issue of the journal Nature Photonics."
Fred Schubert heads the Rensselaer Lab. He says the coating will be useful in more applications than just communications.
Mr. FRED SCHUBERT (Director, Rensselaer Polytechnic Institute): For example, in a solar cell we would like the light that we receive from the sun to end up in the semi-conductor material where we can convert the light to electricity.
PALCA: At the moment, solar cells reflect away some of the sunlight that shines on them. So far, this new coating has only been made in an academic laboratory. But Schubert says several companies have expressed interest in the process.
Mr. SCHUBERT: I believe that this technology is very amenable to manufacturing and very amenable to the transfer of academic technology to the industrial sector.
PALCA: But physicist Charles Falco says it may be a bit early to start placing orders for the new coating. Falco is a professor of optical physics at the University of Arizona in Tucson. He says a lot of coatings - what he calls films - look promising in the lab but fail in the real world.
Professor CHARLES FALCO (Optical Physics, University of Arizona): I'm very interested to know whether the films have long-term stability, because that typically is a problem and that would limit applications of it.
PALCA: And Falco says other teams have also had success developing coatings that reduce reflectivity. So it would be wrong to consider the Rensselaer work a breakthrough.
Prof. FALCO: It's not in the same category as certainly being able to achieve something that was never possible before. It makes things a little bit better, and that's always good in science.
PALCA: In other words, it reflects well on scientific progress.
Joe Palca, NPR News, Washington.
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