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Student Innovation at Rensselaer Polytechnic Institute Holds Key To Safer Remote Detection of Dangerous Materials
Benjamin Clough Is One of Three Finalists for
the $30,000 2011 Lemelson-MIT Rensselaer Student
Prize
Benjamin Clough has developed a novel method for
eavesdropping on terahertz information hidden in invisible
plasma acoustic bursts. The doctoral student at Rensselaer
Polytechnic Institute has demonstrated a promising technique
that employs sound waves to boost the distance from which
researchers can use powerful terahertz technology to remotely
detect hidden explosives, chemicals, and other dangerous
materials.
Clough, a student in the Department of Electrical,
Computer, and Systems Engineering at Rensselaer, is one of
three finalists for the 2011 $30,000 Lemelson-MIT Rensselaer
Student Prize. A public ceremony announcing this year’s winner
will be held at 7 p.m. on Wednesday, March 9 in the auditorium
of the Rensselaer Center for Biotechnology and
Interdisciplinary Studies. For more information on the ceremony
visit: http://www.eng.rpi.edu/lemelson/
Clough’s project is titled “Terahertz Enhanced Acoustics,”
and his faculty adviser is Xi-Cheng Zhang, the J.
Erik Jonsson Professor of Science at Rensselaer and director of
the university’s Center for Terahertz Research.
The Rensselaer Center for
Terahertz Research is one of the most active groups
worldwide to apply terahertz wave technology for security and
defense applications. Sensors using terahertz waves can
penetrate packaging materials or clothing and identify the
unique terahertz “fingerprints” of many hidden materials.
Terahertz waves occupy a large segment of the electromagnetic
spectrum between the infrared and microwave bands. Unlike
X-rays and microwaves, terahertz radiation is very low energy
and poses no known health threat to humans.
A key practical limitation of terahertz technology, however,
is that it only works over short distances. Naturally occurring
moisture in air absorbs terahertz waves, weakening the signal
and sensing capabilities. This distance limitation is not ideal
for applications in bomb or hazardous material detection, where
the human operator wants to be as far away as possible from the
potential threat.
Clough’s patent-pending solution to this problem is a new
method for using sound waves to remotely “listen” to terahertz
signals from a distance. Focusing two laser beams into air
creates small bursts of plasma, which in turn create terahertz
pulses. Another pair of lasers is aimed near the target of
interest to create a second plasma for detecting the terahertz
pulses after they have interacted with the material. This
detection plasma produces acoustic waves as it ionizes the air.
Clough discovered that by using a sensitive microphone to
“listen” to the plasma, he could detect terahertz wave
information embedded in these sound waves. This audio
information can then be converted into digital data and
instantly checked against a library of known terahertz
fingerprints, to determine the chemical composition of the
mystery material.
So far, Clough has successfully demonstrated the ability to
use acoustics to identify the terahertz fingerprints from
several meters away. He has separately demonstrated plasma
acoustic detection from 11 meters, limited only by available
lab space. Along with the increased distance from the
potentially hazardous material, an additional advantage is that
his system does not require a direct line of sight to collect
signals, as the microphone can still capture the audio
information. Potential applications of Clough’s invention,
which circumvents the fundamental limitations of remote
terahertz spectroscopy, include environmental monitoring of
atmospheric conditions, monitoring smokestack emissions,
inspecting suspicious packages, or even detecting land mines —
all from a safe distance.
Clough has presented his findings at several international
conferences, and the details of his work have been published in
Optics Letters and Physical Review
E. His new method for terahertz sensing
has created the possibility to obtain terahertz spectroscopic
information from a distance, bypassing a key limitation of high
terahertz absorption by water vapor in air.
A National Science Foundation Integrative Graduate Education
and Research Traineeship (IGERT) fellow, Clough is deeply
committed to his research activities. He received the
Rensselaer Founders Award of Excellence in 2009, as well as the
Rensselaer NSF IGERT Best Presenter Award in 2010.
Hailing from Albuquerque, N.M., Clough grew up immersed in
science and technology. He inherited a love of research from
his father, a retired chemist, and a strong work ethic from his
mother, a retired professor of nursing. Along with his parents,
Clough’s wife, Kara, and older sister, Sandy, are rooting for
him to win the 2011 Lemelson-MIT Rensselaer Student Prize.
Clough said the idea for his innovation struck him while
relaxing on the beach in Mexico during a winter vacation with
his family. Outside the lab and classroom, he enjoys a variety
of activities including playing soccer, snowboarding, and
backpacking with his wife and friends.
Clough received his bachelor’s degree in electrical
engineering from the University of New Mexico. He joined
Rensselaer as a doctoral student in 2007.
About the $30,000 Lemelson-MIT Rensselaer Student
Prize
The $30,000 Lemelson-MIT Rensselaer Student Prize is
funded through a partnership with the Lemelson-MIT Program,
which has awarded the $30,000 Lemelson-MIT Student Prize to
outstanding student inventors at MIT since 1995.
About the Lemelson-Mit Program
Celebrating innovation, inspiring youth
The Lemelson-MIT Program celebrates outstanding innovators
and inspires young people to pursue creative lives and careers
through invention.
Jerome H. Lemelson, one of U.S. history’s most prolific
inventors, and his wife, Dorothy, founded the Lemelson-MIT
Program at the Massachusetts Institute of Technology in 1994.
It is funded by the Lemelson Foundation and administered by the
School of Engineering. The Foundation sparks, sustains, and
celebrates innovation and the inventive spirit. It supports
projects in the U.S. and developing countries that nurture
innovators and unleash invention to advance economic, social
and environmentally sustainable development. To date the Lemelson Foundation has
donated or committed more than U.S. $150 million in support of
its mission.
For information on past winners of the $30,000
Lemelson-MIT Rensselaer Student Prize, visit:
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Published
February 28,
2011 |
Contact: Michael Mullaney
Phone: (518) 276-6161
E-mail: mullam@rpi.edu |
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