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FOR IMMEDIATE RELEASE
September 29, 2004

*Device allows naked eye to see motion of 10 nanometers*

*Sandia creates motion detector 1,000 times more sensitive than any known*


	Nanomeasure *Sandia researcher Bianca Keeler studies very fine motion 
formerly unobservable by human eye but now revealed by a laser beam 
interacting with an unusual diffraction grating fabricated at Sandia's 
Microelectronic Development Laboratory.*
*Download 300dpi JPEG image, 'nanomeasure.jpg', 684K 
<http://www.sandia.gov/news-center/news-releases/2004/images/jpg/nanomeasure.jpg>* 
(Media are welcome to download/publish this image with related news 
stories.)

ALBUQUERQUE, N.M. -- A new class of very small handheld devices can 
detect motion a thousand times more subtly than any tool known.

"There was nothing in the [optics] literature to predict that this would 
happen," says Sandia National Laboratories researcher Dustin Carr of his 
group's device, which reflects a bright light from a very small moving 
object.

Sandia is a National Nuclear Security Administration laboratory.

Carr, who earlier gained fame as a graduate student at Cornell for his 
creation of a nanoguitar, was selected this week by MIT's science 
magazine /Technology Review/ as one of the year's top 100 researchers 
under the age of 35.

The patent-applied-for device will be the subject of an invited talk at 
the SPIE Optics East convention in Philadelphia in October, delivered by 
Sandia team member Bianca Keeler.

Like shadow pictures projected onto a wall by shining light through the 
fingers of one hand moving over the fingers of the other, the relatively 
simple measuring device depends upon a formerly unrecognized property of 
optics: light diffracted from very small gratings that move very small 
lateral distances undergoes a relatively big, and thus easily 
measurable, change in reflection. A motion of 10 nanometers can be seen 
by the naked eye, says Carr.

A nanometer is one-thousandth of a micron, which is one millionth of a 
meter.

As for the device, size matters and small is crucial. "In standard MEMS 
[microelectromechanical] applications, though the devices are small, 
very few things that sell are dominated by a search for further 
miniaturization. There's not a motivation in MEMS to make things still 
smaller as a matter of cost. Economics of scale for integrated circuits 
just don't apply to MEMS. But our device couldn't exist unless you made 
it this small," he says. Features are in the 100-200 nanometer range, 
with 300 nm between top and bottom combs and 600 to 900 nm between comb 
teeth.

Sub-wavelength interference effects cause the visual display.

"Making use of the effect is fairly obvious once you realize it 
happens," he says.

Fabricated out of polysilicon by standard lithography techniques like 
those used to make MEMS devices, the Sandia system uses two tiny 
comb-like structures (instead of fingers) laid one over each other. The 
bottom comb is locked rigidly in place. The top comb is secured only by 
horizontal springs. Any tiny motion sends the top comb skittering over 
the bottom comb, laterally deforming the grating. A very tiny 
disturbance changes by an unexpectedly large amount the amplitude of 
light -- in the visible to near-infrared range -- diffracted from a tiny 
laser beam shining upon the apparatus.

Micrograph of device *SEM (scanning electron micrograph) of the device, 
with scale bar at bottom representing 10 microns. The top grating layer 
is suspended by 4 springs and actuated by two side comb drives. The 
second, fixed grating layer is hidden below the first. The area of the 
grating itself is 10 microns x 10 microns.*
*Download 300dpi JPEG image, 'device.jpg', 168K 
<http://www.sandia.gov/news-center/news-releases/2004/images/jpg/grating.jpg>* 
(Media are welcome to download/publish this image with related news 
stories.)
        

The measuring device, still in the laboratory stage, is in effect a kind 
of accelerometer, about the size of the inexpensive 
microelectromechanical devices that open automobile air bags. Fabricated 
by the same processes that mass-produce silicon computer chips, the 
device has multiple possible uses.

"If you can make very sensitive detectors very cheaply and very small, 
there are huge applications," says Carr. "Made small, synchronized, 
cheap, and placed on every block, we could take data from all these 
sensors at once and measure the motion of the earth when there's not an 
earthquake. So we could learn what leads up to one."

Another use would be for skid and traction control in cars, detecting if 
the back end of the car is moving in a different direction from the 
front end.

"Such devices also could take the place of inertial navigation systems," 
Carr says. These typically require large gyroscopes to keep commercial 
airplanes moving on a preset course. "We could have handheld-sized 
devices on Volkswagens that would work even in a tunnel."

Other defense applications are possible, he says.

He sees a time frame of three to five years before the devices are 
available for use.

Says James Walker, former Director of Advanced Technologies at Tellium, 
Inc., former manager of the MEMS Network Element Sub-systems Group at 
Lucent, Bell Laboratories, and now an independent consultant and patent 
agent, "To my understanding, it is the first time anyone has tried to 
manipulate the optical near-field region in order to affect changes to 
the far-field characteristics of a grating. The ability to do this is a 
direct result of the nano-scale nature of the device. Due to its high 
responsivity-to-displacement ratio, I see it having significant, 
far-reaching application in areas as diverse as chemical sensing, 
infrared imaging, accelerometry, and displays."

------------------------------------------------------------------------

Sandia is a multiprogram laboratory operated by Sandia Corporation, a 
Lockheed Martin company, for the U.S. Department of Energy's National 
Nuclear Security Administration. Sandia has major R&D responsibilities 
in national security, energy and environmental technologies, and 
economic competitiveness.

*Sandia media contact:* Neal Singer, nsinger AT sandia.gov 
<mailto:nsinger AT sandia.gov>, (505) 845-7078