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