An Optical Immersion
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Duncan (Ph.D. '91) is an associate professor working in optics
at the University of Dayton. In the background is the electronically
addressed spatial light modulator that Duncan worked with as
a Ph.D. candidate in Tech's Optical Image Processing Laboratory.
Sometimes finding your niche takes a false start or two, as
happened with Bradley Duncan (Ph.D. '91), the first Bradley Fellow
Ph.D. graduate. Now an associate professor at the University
of Dayton, with a thriving research program and an "Engineering
Professor of the Year" award, Duncan almost did not go to
college. Then he almost quit electrical engineering.
A self-described lackluster high school student, he was not convinced
that he should go to college. "I applied only to Virginia
Tech, figuring that if they didn't accept me, I just didn't need
to go to college. It is amazing that I did so well, then ended
up as a professor. I did not blossom until I was in college."
Duncan says that he chose electrical engineering for "all
the wrong reasons." When he was in high school, the first
personal computers were being developed and he went into EE to
build computers. "I then found I hated computers,"
he said. "I discovered this as a co-op student. I was programming
all the time and detested it."
He decided the field was not for him and prepared to drop EE
and major in mathematics. "I just couldn't stand the thought
of programming computers all my life."
Then he discovered that electrical engineers also work in optics.
He completed a bachelor's in EE, and stayed at Tech for a master's,
working with Rick Claus in the department's fiber optics program.
Optics became a passion and he decided to pursue a Ph.D. "I
was interested in rounding out my optics background." He
worked with T.-C. Poon, exploring optical image processing.
After earning his Ph.D., Duncan joined the faculty of the University of Dayton (UD)
with a joint appointment in electrical and computer engineering
department and the graduate
program in electro-optics. "UD was one of the few programs
in the country that offered a degree in optics. I got in on the
ground floor of something that grew fast."
In the 10 years since joining UD's faculty, Duncan's interest
in optics has taken him into many areas, including laser radar,
liquid crystals, aero-optics, and wireless communications. With
Wright-Patterson Air Force Base nearby, much of his work relates
to Air Force issues. "As a faculty member, you learn to
follow the money," he said.
When he started at UD, he joined an ongoing project in laser
radar. "It's just like regular radar," he explained.
"We sent a pulse of light, looked at the backscatter return,
and obtained information from the target that was illuminated."
From there, he branched into different aspects, including optimizing
laser radar receivers, and heterodyne and direct detection. "Heterodyne
detection allows velocity as well and range information, while
direct receivers are easier to build, but do not always give
the same amount of information," he explained.
Another Air Force laser radar project involved exploring methods
to overcome the disturbance caused by the turbulent shear layer
for airborne laser radar systems. "If the Air Force wants
to shoot a laser radar beam out of a portal, the beam tends to
break up when passing through the turbulent shear layer. It's
like looking at a shimmer on a hot summer day," he explained.
"The laser twinkles," he said.
A current project in non-mechanical beam steering explores the
best way to send and direct a beam with as much precision and
energy as possible. "Conventional mechanical devices do
not lend themselves to highly accurate, rapid random pointing,"
he said. "Optical phased arrays, on the other hand, have
the potential to overcome many of those limitations." The
team is working on optical phased array technology based on liquid
Duncan has also worked with non-destructive evaluation using
interferometric and real-time holographic schemes for detecting
and monitoring defect and defect precursors in advanced aluminum
and titanium alloys.
In addition to research, Duncan has been active in building the
university's optics teaching program. He has developed three
new courses in the guided wave optics area at the graduate level.
He is also leading UD's effort to bring optics to the undergraduate
level and built an NSF-funded Photonics Laboratory, which is
used in undergraduate ECE and physics courses. He has several
graduate and undergraduate students working on projects in the
laboratory this semester, and used the laboratory last semester
for projects and demonstrations with the introduction to fiber
Perhaps if undergraduates at UD can be exposed to the variety
and depth of experience in optics, they can appreciate the area
of electrical engineering that has captivated Duncan. "A
lot of students are trying to figure out what they are doing
here and why," he said. "My advice is to find something
they love. I have no innate brilliance. I spend the time immersed
in optics. And I enjoy it."