One of the greatest challenges facing engineers who design tiny microelectromechanical systems (MEMS) is finding ways to power machines that often measure only microns across. The answer, it seems, may be blowing in the optical wind. Researchers at the Hungarian Academy of Sciences have built resin-based structures that operate on principles similar to those that propel windmills.
Rather than extracting energy from wind, however, the new devices are driven by beams of light. In one demonstration of the potential for light-powered machinery, an optical vane turned a series of interlinked cogwheels, each only 5 microns in diameter.
The researchers manufactured various shapes for their devices, including helixes and propellers, by curing resin with focused laser light. A particularly promising structure that resembles a common lawn sprinkler (see figure at http://www.aip.org/physnews/graphics) spins at several revolutions per second when illuminated by a 20 milliwatt laser beam.
In addition to providing torque to miniature gears, pumps and other micro-machines, the light-powered rotors could be used to measure fluid properties on micrometer scales.
Alternatively, it may be possible to study the mechanical properties of certain molecules, such as proteins or DNA, by fixing one end to a surface, attaching a rotor to the other end, and using light to apply a twisting force. (Péter Galajda; Pál Ormos, Applied Physics Letters, 8 January 2001.)
(Editor's Note: This item is adapted [with minor formatting changes only] from PHYSICS NEWS UPDATE, The American Institute of Physics Bulletin of Physics News Number 520 January 12, 2001 by Phillip F. Schewe, James Riordon, and Ben Stein.)
[Contact: Pál Ormos]
15-Jan-2001
