Metamaterials have long been used by scientists for the manipulation of electromagnetic waves, like visible light, to allow the waves to act in ways not found in nature. Now, researchers are taking this technology to find new ways of manipulating light using a new class of metamaterial.
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The new type of metamaterial can be "tuned" to change the color of light—such technology can allow on-chip optical communication creating effective fiber-optic telecommunication networks. "Today's computer chips use electrons for computing. Electrons are good because they're tiny," says Professor Viktor Podolskiy of the Department of Physics and Applied Physics who is also the project's principal investigator at UMass Lowell. "However, the frequency of electrons is not fast enough. Light is a combination of tiny particles, called photons, which don't have mass. As a result, photons could potentially increase the chip's processing speed."
On-chip communication can be enabled through the conversion of electrical signals into pulses of light, ultimately replacing obsolete copper wires present on conventional silicon chips for the final result of core-to-core communication on the same chip. "The end result would be the removal of the communication bottleneck, making parallel computing go so much faster," explains Podolskiy.
“The illustration shows two incoming (red) photons being converted into one reflected (green) photon as a result of light interaction with the nanowire structure in the metamaterial. The nanowires are about 100 nanometers apart from center to center, which is about one-fifty-thousandth the diameter of human hair.”
Credit: UMASS Lowell
The interactions of photons in light decides information processing and optical computing and the energy of these photons concludes the color of light. "The vast majority of everyday objects, including mirrors, lenses and optical fibers, can steer or absorb these photons. However, some materials can combine several photons together, resulting in a new photon of higher energy and of different color,” says Podolskiy. "The enhancement comes from the way the metamaterial reshapes the flow of photons," he said. "The work opens a new direction in controlling the nonlinear response of materials and may find applications in on-chip optical circuits, drastically improving on-chip communications."
Source: UMASS Lowell