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.
The effect was first demonstrated in limited cases more than a decade ago, but by achieving it in novel ways, two groups “have made negative refraction a practical reality at optical frequencies,” said Sir John Pendry, a professor of physics at Imperial College London who was not involved in the new work.
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.
In addition to biological imaging, perfect lenses could be used for single molecule biosensing, nanofabrication, light harvesting and (in theory) perfectly efficient solar panels, among other possibilities.