- Associated Press - Sunday, March 30, 2014

EAST LANSING, Mich. (AP) - Compared with Harold Edgerton’s electronic stroboscope, the mechanical shutters on even the fastest cameras moved at a glacial pace.

The microsecond flashes of light from the device Edgerton began working on in the 1920s as a graduate student at MIT sliced time thinner, making visible a world that happened too fast for the naked eye to register.

Edgerton’s iconic photographs revealed the architecture of milk droplets, hummingbirds frozen in flight, bullets at the instants they tore through apples and light bulbs and playing cards.

The microscope that Chong-Yu Ruan’s laboratory is developing at Michigan State University works on similar principles, though his objects of interest are far smaller and the seconds sliced even narrower, according to the Lansing State Journal ( http://on.lsj.com/1nJWIPN ).

It is fast enough to capture the rupture or formation of a chemical bond, the fleeting deformation of a single molecule.

Which has the potential to refine or remake our understanding of the basic mechanisms of chemistry, to open up new possibilities in materials science and medicine and nanotechnology.

Imaging materials in transformation, capturing the process of change, “is really important for understanding the inner workings of micro- and nanostructures,” Ruan said.

“This allows you to look at many open questions that people have been debating over the years.”

Conventional electron microscopes can produce images at atomic scales, of course. The problem is that those images require millisecond-long exposures or longer.

A millisecond is a fraction of the blink of an eye (the average eye blink lasts about 300 milliseconds), but “it’s like a billion years for a molecule,” said Ruan, who is a professor in the Department of Physics and Astronomy.

The final images are averages, akin to the way a human eye sees the fluttering of a dragonfly’s wing or a pencil wobbled in the hand until it appears to bend.

Electron microscopes typically use a filament to emit the electrons needed for imaging. They come out at random.

Ruan’s Ultrafast Electron Microscope, a cascade of wires and tubes, foil-wrapped parts and control modules that takes up of Ruan’s laboratory, uses a femtosecond laser to trigger the electron pulses.

A femtosecond is 0.000000000000001 seconds. Put differently, a femtosecond is to a second what a second is to 32 million years.

The laser with its ultrafast pulses is Ruan’s stroboscope.

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