Tag Archives: nanoplasmonic structures

Rainbows, what are we going to do with them?

The title is attention-getting initially then quickly leads to confusion for anyone not familiar with plasmonics, “Trapping a rainbow: Researchers slow broadband light waves with plasmonic structures.” I have to confess to being more interested in the use of the metaphor than I am in the science. However in deference to any readers who are more taken by the science, here’s more from the March 14, 2011 news item on Nanowerk,

A team of electrical engineers and chemists at Lehigh University have experimentally verified the “rainbow” trapping effect, demonstrating that plasmonic structures can slow down light waves over a broad range of wavelengths.

The idea that a rainbow of broadband light could be slowed down or stopped using plasmonic structures has only recently been predicted in theoretical studies of metamaterials. The Lehigh experiment employed focused ion beams to mill a series of increasingly deeper, nanosized grooves into a thin sheet of silver. By focusing light along this plasmonic structure, this series of grooves or nano-gratings slowed each wavelength of optical light, essentially capturing each individual color of the visible spectrum at different points along the grating. The findings hold promise for improved data storage, optical data processing, solar cells, bio sensors and other technologies.

While the notion of slowing light or trapping a rainbow sounds like ad speak, finding practical ways to control photons—the particles that makes up light— could significantly improve the capacity of data storage systems and speed the processing of optical data.

The research required the ability to engineer a metallic surface to produce nanoscale periodic gratings with varying groove depths. This alters the optical properties of the nanopatterned metallic surface, called Surface Dispersion Engineering. The broadband surface light waves are then trapped along this plasmonic metallic surface with each wavelength trapped at a different groove depth, resulting in a trapped rainbow of light.

You can get still more scientific detail in the item but I found a later posting, April 12, 2011 news item, also on Nanowerk, where the researcher Qiaoquiang Gan (pronounced “Chow-Chung” and “Gone”) gave this description for his work,

An electrical engineer at the University at Buffalo, who previously demonstrated experimentally the “rainbow trapping effect” [emphasis mine] — a phenomenon that could boost optical data storage and communications — is now working to capture all the colors of the rainbow.

In a paper published March 29 in the Proceedings of the National Academy of Sciences, Qiaoquiang Gan (pronounced “Chow-Chung” and “Gone”), PhD, an assistant professor of electrical engineering at the University at Buffalo’s School of Engineering and Applied Sciences, and his colleagues at Lehigh University, where he was a graduate student, described how they slowed broadband light waves using a type of material called nanoplasmonic structures.

Gan explains that the ultimate goal is to achieve a breakthrough in optical communications called multiplexed, multiwavelength communications, where optical data can potentially be tamed at different wavelengths, thus greatly increasing processing and transmission capacity.

“Light is usually very fast, but the structures I created can slow broadband light significantly,” says Gan. “It’s as though I can hold [emphasis mine] the light in my hand.”

I like the notion of ‘holding’ a rainbow better than ‘trapping’ one. (ETA April 18, 2011: The original sentence, now placed at the end of this posting, has been replaced with this: There’s a big difference between the two verbs, trapping and holding and each implies a difference relationship to the object. Which would you prefer, to be trapped or to be held? What does it mean to the one who does the trapping or the holding? Two difference relationships to the object and to the role of a scientist are implied.

It’s believed that the metaphors we use when describing science have a powerful impact on how science is viewed and practiced. One example I have at hand is a study by Kevin Dunbar mentioned in my Jan. 4, 2010 posting (scroll down) where he illustrates how scientists use metaphors to achieve scientific breakthroughs. Logically, if metaphors help us achieve breakthroughs, then they are quite capable of constraining us as well.

Meanwhile, this gives me an excuse to include this video of a Hawaiian singer, Israel Kamakawiwo’ole and his extraordinary version of Somewhere over the Rainbow. Happy Weekend!

The original (April 15, 2011) sentence:
It’s more gentle and implies a more humble attitude and I suspect it would ultimately prove more fruitful.