Molecular imaging gets a new tool
In September of last year I happened to be in Europe on “beam day”–the day on which the Large Hadron Collider (LHC) was turned on for the first time.
In September of last year I happened to be in Europe on “beam day”—the day on which the Large Hadron Collider (LHC) was turned on for the first time. The LHC is a particle accelerator at CERN, the European high-energy physics laboratory near Geneva in Switzerland. There can be few events—and even fewer scientific ones—that have achieved such universal pan-European media coverage as did this firing up of the LHC. It was, I would guess, front-page news in all of Europe’s leading newspapers. And even in the run-up to beam day you couldn’t miss the story–though the focus then was more on the “end-of-the-world” theories (such as whether the LHC would create a Black Hole right here on Earth) than on the successful completion of a multinational “Big Science” collaboration that spanned decades.
Now fast-forward to this September and another Big Science project here in the USA. This month the SLAC National Accelerator Laboratory (Stanford, CA) will open the world’s shortest-wavelength free-electron laser for use by guest scientists. And while this event is hardly likely to attract anything close to the media frenzy surrounding the LHC, it is nonetheless a noteworthy milestone. The Linac Coherent Light Source (LCLS) is the first free-electron laser to emit hard x-rays, delivering 80 fs pulses at wavelengths tunable between about 0.15- and 1.5-nm–pulses that can capture images of atoms and molecules in motion.
A different route to nanoscale imaging involves overcoming the optical diffraction limit. Approaches to subwavelength imaging include the use of near-field optics but more recently metamaterials–whose optical properties can be tailored by varying their internal structure–have presented an opportunity for a novel approach based on a negative-refractive-index “superlens.”
Meanwhile, yet another imaging technique–optical coherence tomography (OCT)–is taking aim at new opportunities. Typically considered a medical imaging tool, OCT is finding applications in an industrial setting for nondestructive subsurface imaging of small, 2-D surface areas or 3-D structures.
Stephen G. Anderson
Associate Publisher/ Editor in Chief