New sensor could improve safety, security

A new kind of sensor could be more efficient, versatile and cheaper to use in airport security scanners and collision avoidance systems, US developers say. Researchers at Duke University reported in the journal Science a new manmade metamaterial that can act as a lens to image scenes using fewer components than conventional detectors. Using this metamaterial means additional equipment needed for conventional detector systems -- like lenses, mechanical positioners and data storage or transmission devices -- are not required, they said. The material, a thin laminate with row-upon-row of tiny squares etched onto copper, each tuned to a different frequency of light, is flexible and durable enough to be attached to a wall, wrapped around corners or even laid on the floor like a rug, making it an inexpensive alternative for a variety of sensing applications, the researchers reported. The system works with microwave light and produces two-dimensional images. "By taking advantage of the unique properties of these metamaterials, we were able to create a system capable of microwave imaging without lenses or any moving parts," Duke graduate student John Hunt said. Unlike current imaging systems that must move a single sensing device with a small aperture to scan an object or a person, the new device can scan the entire field at once, resulting in faster and more efficient screening, the researchers said. "Using conventional systems such as airport security cameras or collision-detection devices, you have to wait for a scan to complete before you can see an image, while the new system can scan an entire range at once," Hunt said.