24 July 2007
Scientists who want to view fast moving images of the tiniest droplet or the smallest structure have until now been able to see them as two-dimensional, but thanks to a team of Monash University physicists can see them in 3-D.
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| Schematic showing how a 3D line profile(white line) can be obtained from Lloyd's fringes in surface electron microscopy. |
David Jesson, Konstantin Pavlov and Michael Morgan have solved a major problem in surface electron microscopy by developing a new technique to determine surface shape and depth.
The breakthrough discovery will enable scientists to see, in real time, 3-D images of materials evolving and be able to see how they behave and interact on surfaces.
"How materials develop and react with other materials forms the basis of a great deal of scientific research and what we have achieved is the ability to view small clusters on surfaces as they are evolve and interact," Professor Jesson said.
"Previously, scientists have had to freeze-frame each image by removing specimens from the growth or heating environment and link them together. Our discovery means that images can be now captured as a real time video which also shows the depth of the structure," he said.
"This will open up new opportunities for theorists to model and understand the changes in nanostructures being developed for a new generation of computers, lasers and communication systems, and is a new tool for studying surface shape dynamics on small-length scales," he said.
Professor Jesson's team discovered 3-D imaging of nanostructures is possible while using photoemission electron microscopy, or PEEM, to look at droplets of liquid gallium sitting on a mirror-flat surface of gallium arsenide." We created interference fringes by illuminating the droplets with ultraviolet light using a classic 19th century physics experiment known as Lloyd's Mirror, where light reflected off a mirror interferes with light coming directly from the source," he said.
They found that the bright interference fringes result in the emission of electrons which can be imaged using a surface electron microscope. Applying the same principle as viewing a standard topographic map of a mountain range, they were able to determine the height of the structure by counting the contour lines.
"Fringes are sensitive to the 3-D shape of the gallium droplets and are distorted by the electric field due to the topographic features. This can then be corrected using image processing, to provide a real-time relief map showing how the surface of the metallic droplets evolves," Professor Jesson said.
This work was recently published in Physical Review Letters 99 (2007) 016103 and is also featured in the Physical Review Focus of the American Physical Society.
For more information, please contact Ms Samantha Blair, Media and Communications on: +61 3 9905 9315.
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