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Terahertz-Controlling Device Is Built
UPI Correspondent Los Alamos (UPI) Dec. 4, 2006 U.S. government scientists say they've built a device that can manipulate terahertz radiation, perhaps leading to new imaging and communications devices. The terahertz, or THz, range of the frequency spectrum lies between infrared and microwave wavelengths. Devices generating and detecting THz radiation are in development but techniques to control the waves are lagging. But Hou-Tong Chen and colleagues at the Los Alamos National Laboratory have demonstrated metamaterials -- objects with properties based on their structure instead of the materials they are composed of -- can be designed to efficiently control THz waves in real time. The researchers said they have built a device that consists of a semiconductor substrate with an array of gold structures on top. By controlling the voltage that is applied between the substrate and the metamaterial, the team can modulate the transmitted intensity up to 50 percent. They said their demonstration exceeds the performance of existing electrical THz modulators and it's hoped the efficiency will be improved further by optimizing the device. The experiment is detailed in the current issue of the journal Nature.
Source: United Press International Community Email This Article Comment On This Article Related Links Powering The World in the 21st Century at Energy-Daily.com Los Alamos National Laboratory Powering The World in the 21st Century at Energy-Daily.com
Switchgrass Aims For Ethanol At One Dollar A Gallon
Providence RI (SPX) Dec 06, 2006In his 2006 State of the Union address, President Bush acknowledged the potential for switchgrass as a source of ethanol to reduce the nation's reliance on foreign oil. Unlike corn, which is currently used for ethanol production, switchgrass can be grown on marginal soils, is useful as wildlife habitat, and requires little use of fertilizers, insecticides or irrigation. |
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