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.

Sep 1st, 2009
Th Steveandersonsm

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.

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Stephen G. Anderson
Associate Publisher/ Editor in Chief
stevega@pennwell.com

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