April 15 - Researchers are taking Star Trek 'tractor beam' technology from science fiction to science fact. The scientists from Scotland's University of St Andrews and the Institute of Scientific Instruments (ISI) in the Czech Republic have found a way to generate a special optical field that uses light to move microscopic objects. Jim Drury has more.
Once the stuff of science fiction, a man-made 'tractor beam' moves tiny polystyrene beads towards a light source, demonstrating the potential of light to manipulate matter. In nature, light particles repel matter, but in a Czech laboratory scientists have managed to reverse the process for the first time...and control it on a microscopic level. University of St. Andrews researcher Tomas Cizmar led the team. SOUNDBITE (English) 'TRACTOR BEAM' LEAD RESEARCHER DR TOMAS CIZMAR, RESEARCH FELLOW IN THE SCHOOL OF MEDICINE AT THE UNIVERSITY OF ST ANDREWS, SAYING: "Our implementation is a clear demonstration of this, that the radiation pressure for some specific parameters can reverse, so instead of pushing like sunlight pushes away comet tails, you can obtain pulling, so the particles would propagate towards the source of the light." When microscopic objects are hit by light beams they're usually forced along in the same direction by light photons. But Cizmar and colleagues at the Czech Institute of Scientific Instruments found a tiny range where this premise could be overturned. SOUNDBITE (English) 'TRACTOR BEAM' LEAD RESEARCHER DR TOMAS CIZMAR, RESEARCH FELLOW IN THE SCHOOL OF MEDICINE AT THE UNIVERSITY OF ST ANDREWS, SAYING: "It only occurs for very small particles, in the range of between half a micrometer up to say five micrometers for a visible light....We only used two beams, or in a sense we only used one reflected from a mirror that provided us with much simpler geometry to see this phenomena clearly. That's where the significance is, the experimental verification that something like that truly exists." The team hope their research could one day have future medical applications... technologies that could isolate individual cells from blood samples, for example. NASA is funding its own study into using 'tractor beams' to manipulate and capture planetary particles in space. Cizmar says that will be difficult, as reversing anything other than microscopic objects would require enormous volumes of heat...but he says his team has at least laid the groundwork for future developments.