Physicists Close In on ‘Perfect’ Optical Lens

^{Henri Lezec, a scientist at the National Institute of Standards and Technology in Gaithersburg, Md., aligning the optical system with which he and his colleagues demonstrated 3-D negative refraction of ultraviolet light for the first time.}

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From ribosomes assembling proteins to viruses attacking cells, the main dramas in biology happen on a scale that is, tantalizingly, just one order of magnitude below the resolution of the best optical microscopes. Conventional lenses have a hard limit: The light waves propagating through them cannot carry details much smaller than their own crests and troughs. Clever workarounds have emerged, such as structured illumination microscopy, but all have limitations: They are too slow to image dynamic processes, or they poison cells with too much light.

Now, following recent breakthroughs, researchers are laying the groundwork for a "perfect lens" that can resolve sub-wavelength features in real time, as well as a suite of other optical instruments long thought impossible. These devices sidestep old optical limits by bending rays of light the "wrong" way - a phenomenon known as negative refraction.

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