Georgia Tech's Research Horizons magazine - Fall 1999
Photonic Sensors
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An
integrated optic interferometric sensor, developed
by GTRI scientist Nile Hartman, quickly detects
even the smallest amounts of various contaminants
in air, soil, groundwater and food.
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In the late 1980s, GTRI researcher Nile Hartman developed an optical sensing
apparatus and sensing method that provided improved stability and lower
cost than what was then available. In 1990, that invention was patented,
but Hartman had already taken his research to the next level. He was developing
an integrated optic interferometric sensor that would quickly detect even
smaller amounts of various contaminants in air, soil, groundwater and food.
In 1997, the work reached a major milestone when it was patented by Hartman
and the Georgia Tech Research Corporation.
Subsequently, the sensor was licensed commercially by the Atlanta-based
company Photonic Sensor. The company is a recent graduate of Georgia Tech's
Advanced Technology Development Center, a business incubator for high-tech
firms.
Hartman's sensor was developed from laser-based technology originally
conceived for optical communication applications. That technology allows
a multichannel microsensor fitted with the proper chemical coatings to simultaneously
detect multiple contaminants. It works like this: The speed of light increases
or decreases when passing through materials of differing optical properties.
Detection of contaminants becomes possible by measuring a contaminant's
influence on the optical properties of the sensor. Then researchers observe
the effects on these properties through changes in the transmitted laser
light.
The sensors have been integrated into an environmental monitoring system
called E-SMART, which can detect and analyze various chemical contaminants,
including heavy metals, solvents, and petroleum oil and lubricants. E-SMART
operates in real time and measures very small amounts of contaminants. In
addition, researchers say it will reduce health and safety risks and help
ensure environmental compliance.
An ongoing series of E-SMART field tests at U.S. Department of Defense
facilities will precede the product's availability on the national and international
commercial markets. When it does become available, the E-SMART system and
also the sensor as a stand-alone environmental monitor will have numerous
applications in the private sector, from manufacturing operations to water
treatment facilities.
An additional application of the photonic sensor technology is a rapid-response
biosensor for detecting microbial contamination in food, particularly poultry.
The biosensor incorporates integrated optics, immunoassay techniques and
surface chemistry skills. Hartman developed it in collaboration with Dr.
Paul Edmonds, an associate professor of biology at Georgia Tech, and Dr.
Dan Campbell, a research scientist in GTRI. A field test in a north Georgia
poultry plant is expected to begin later this fall.
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