[EAS]Optical Windmills

pjk peter.kindlmann at yale.edu
Sat Jan 13 03:50:52 EST 2001

Subject:   Optical Windmills

More ingenious MEMS devices.  --pjk

excerpted 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 

TILTING AT OPTICAL WINDMILLS. 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 (P+l Ormos,
pali at everx.szbk.u-szeged.hu, 36-62-433-465) 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. (PÇter Galajda; P+l Ormos, Applied Physics Letters, 8
January 2001.)

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