U.S. scientists say they\'ve managed to focus light into a beam just a few nanometers across, which could lead to new applications in computing and other fields. Because light can carry greater amounts of data more efficiently than electrical signals traveling through copper wires, today\'s technology is increasingly based on optics, and focusing light into tinier spaces can squeeze more data through optical fibers and increase bandwidth, researchers at the California Institute of Technology reported. Not that it\'s easy, they said; at sizes smaller than the wavelength of light, a few hundred nanometers in the case of visible light, what\'s called the diffraction limit makes it physically impossible to focus the light any further. But the Caltech researchers said they\'ve developed a new kind of waveguide -- a tunnel-like device that channels light -- that has overcome this natural limit. The device turns light into oscillations of electrons that carry the same information and properties, acting in effect as a proxy for the light, but in a much narrower beam. \"Our new device is based on fundamental research, but we hope it\'s a good building block for many potentially revolutionary engineering applications,\" said Myung-Ki Kim, a postdoctoral scholar and co-author of the study paper published in the journal Nature Photonics.