Wednesday, April 11, 2007

US scientists developed a lens that can transmit images over long distances with a resolution that is not restricted by light wavelength. Conventional lenses can't focus on objects less than half the size of the wavelength of light, so anything smaller will be imaged using an electron microscope. Xiang Zhang and his colleagues at the University of California at Berkeley say that they escaped this limitation with their new far-field superlens. To be correct, Zhang's group developed a superlens in 2005, but at that time it was only capable of projecting an image in the near field so that the sensor used to capture the image had to be placed within nanometers of the lens. But the new FSL can transmit high-resolution images over much longer distances by converting evanescent waves into propagating waves. The US researchers have achieved this improvement by introducing carefully designed corrugations to the surface of the superlens. The purpose of the new Far-Field SuperLens is that it brings the high-resolution image from the near field to the far field in order that it can be seen using a regular microscope or a still digital camera.