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NOBEL PRIZE IN CHEMISTRY Seeing the nanoscale Microscopy and nanotechnology, 2 m convention tells us, should not mix. μ The prefixes on the words themselves give some indication of their intrinsic disparity — a factor of one thousand separates the micro- and the nano-worlds. The 2014 in Chemistry has been awarded to , William Moerner and for helping to bridge this gap with their development of

super-resolved fluorescence microscopy. © 2000 NAS, USA Light is perhaps our most important connection with the world around us. the focus spot. In 2000, Hell experimentally imaging. He and his co-workers combined Seeing is believing, or so they say, and demonstrated a STED microscope with molecules that emitted light of different direct visual observation remains our most a focus spot six times smaller than that colours and superimposed images taken trusted means of scientific discovery and imposed by the diffraction limit. He and his over time while the emitters switched on experimental verification. But light has its team were able to image an Escherichia coli and off. They used this single-molecule limits. Diffraction means that a lens cannot bacterium at a resolution not possible microscope to image intracellular proteins focus a ray to a spot smaller than between in a conventional microscope (pictured; with a nanometre resolution. one third and one half of the wavelength. the image on the left was obtained with STED and single-molecule microscopy This is just a few hundred nanometres for standard confocal resolution and the are already reaping rewards. The three a conventional visible-light microscope: image on the right with the axial resolution Nobel laureates themselves have used good enough to image whole cells, but not improved by STED; T. A. Klar et al., Proc. Natl their techniques to better understand brain to get a detailed view of what is going on Acad. Sci. USA 97, 8206–8210; 2000). synapses, cell division in embryos and inside them. Around a similar time, William Moerner the proteins associated with Huntington’s In 1994, Stefan Hell began developing was trying to isolate the emission from disease. But the real testament to the a concept that he thought could beat this single molecules. He dispersed the green importance of their work is the extent limit called stimulated emission depletion fluorescent protein from a jellyfish in a to which the methods have now been (STED) microscopy. Hell’s idea was to take gel and was able to collect light from just adopted and improved by their colleagues advantage of fluorescence quenching — a one protein when the protein–protein around the world, and the promise of reduction in the intensity of light emitted separation was greater than the diffraction fundamental discoveries yet to come. from a molecule when it is exposed to limit. In 1997, Moerner used this approach too much laser light. One laser stimulates to discover that the emission from these DAVID GEVAUX fluorescence while a second quenches all proteins blinks on and off. In 2006, emission except for that at the centre of Eric Betzig harnessed this effect for Corrected after print: 6 November 2014

OPTOMECHANICS Photons that pivot and shuttle Self-oscillation and shuttling of photons between distinct cavities in a photonic see-saw provide unexpected opportunities in nano-optomechanics. Heedeuk Shin and Peter T. Rakich

n the past few years, micro- and nanoscale of optomechanics. Recent experiments have device topologies that have enabled strong systems have enabled controllable demonstrated the versatility of such device photon–phonon coupling. These include coupling between photons and acoustic ; optomechanical interactions have optomechanical systems based on suspended I 1,2 3,4 phonons in a variety of forms . Quantum been used to implement schemes for coo