GRADUATE STUDY
IN PHYSICS
at the
UNIVERSITY OF
ARKANSAS
To obtain more information or to obtain application
material please visit our web site:
www.uark.edu/depts/physics/graduate/appvisit.html
or contact:
Paul Thibado, Chair
Graduate Admissions Committee
Department of Physics
1 University of Arkansas
Fayetteville, AR 72701
Tel: 501-575-7932
Fax: 501-575-4580
e-mail: thibado@uark.edu
Visit us on our homepage at
http://www.uark.edu/depts/physics/
Front Cover: Graduate student Zheng Lu in
Professor Min Xiao’s optics laboratory.
1
The faculty of the Department of Physics at the University
of Arkansas invite you to consider graduate study here.
The
Department has vigorous programs in research and teaching, and its
relatively small size allows faculty to work closely with graduate
students. The Department is internationally known for research in
lasers, optics, condensed matter physics, and teaching.
Department
receives
substantial
external
The
funding
(~$3,000,000/year) and has state-of-the art research and instructional equipment. The University supports research by providing
Graduate Study at
excellent facilities, such as mainframe and personal computers,
the University of
machine shops, an electronics shop, a glass blowing shop, and a
Arkansas
physics library.
Faculty offer a challenging curriculum. In addition to the
traditional core courses, faculty offer courses in cutting-edge fields
such as laser physics, nonlinear optics, and optical properties of
solids. Many graduate courses such as those listed above, also have
laboratory components.
2
Our graduate program provides students the analytical, creative, and inventive skills needed for successful careers. We are
keenly aware that graduate study not only has to be a stimulating
intellectual experience, but also must lead to interesting careers.
Graduate Study
at the University
of Arkansas
With this in mind, we have developed our graduate program in areas
that have the potential for leading to rewarding careers in or out of
academia (e.g., optics, lasers, condensed matter physics, growth and
characterization of semiconductor heterostructures, etc.).
Those
interested in academic careers also have the opportunity of earning a
master’s degree in physics education, followed by a Ph.D. in traditional research areas.
Almost all of our graduate students are supported by teaching or research assistantships. The stipend at present is over $1,150
per month for the nine-month academic year. Assistantships during
the summer are also available. In addition, tuition is paid by the
University for all graduate assistants. Thus the total financial value
of the graduate assistantship is approximately $17,000 per academic
Financial
Support
year. This, coupled with the low cost of living in the Fayetteville
area, removes much of the financial strain often associated with the
pursuit of a graduate degree.
Graduate students generally spend the first two years as
teaching assistants and thereafter become research assistants. The
University also provides add-on fellowships of $3,000 per year to
especially well-qualified students. Women and minority fellowships
are also available.
3
The Department, which has an international reputation for
research in lasers, optics, and condensed matter physics, currently
consists of 17 research faculty, about 10 post-doctorates and visiting
scientists, 40 graduate students, and about 60 undergraduate students. More than half the faculty are experimentalists. The research
is well-funded by grants from federal sources (about $2.3 million in
the 2000-2001 fiscal year) and has produced more than 100 papers
published in the past two years in major research journals. An indication of the dynamic growth of the department is the hiring of
eleven young faculty over the last eleven years.
The faculty
includes three fellows of the APS, a University Professor, and four
recipients of the National Science Foundation Young Investigator
(NYI) and Faculty Early Career Development (CAREER) awards.
Areas of research emphasis include atomic and molecular
physics, scattering theory, laser spectroscopy, photothermal spectroscopy, laser physics, nonlinear optics, quantum optics, light scattering studies from condensed media, high pressure research,
physics of novel magnetic materials, growth and characterization of
semiconductor heterostructures, surface physics, light induced
waveguides, astrophysics, and physics education. The thalliumbased superconductor discovered in this department held the world
record of highest temperature superconductor for about five years.
Research facilities include several ultra-violet, visible and
infrared gas lasers as well as several ultra-high stability CW dye and
solid-state laser systems. Additional resources include ultra-fast
(femtosecond) and ultra-high power pulsed solid state laser systems,
crystal growth and thin film deposition equipment, and a SQUID
The Department
4
magnetometer. A $1.7 million semiconductor growth and characterization facility was recently completed which combines
semiconductor growth using molecular beam epitaxy (MBE)
with a powerful scanning tunneling microscope.
Excellent
sample characterization and research facilities equipped with
X-ray diffractometer (XRD), scanning electron microscope
(SEM), atomic force microscope (AFM), and Raman spectrom-
The Department
eter are available at the High Density Electronics Center
(HiDEC) at the University. A wide range of on- and off-campus computer systems is available for the theoretical studies.
The Department, housed in its own building with an
area of 42,000 square feet, was recently renovated at a cost of
about $4 million to bring it up to the standards required for the
state-of-the-art research. All offices and laboratories are wired
into a fiber optic computer network and part of Internet 2. The
physics research library and the physics machine shop are in the
building, and glass and electronics shops are nearby.
The Department recently won a Materials Research
Science and Engineering Center (MRSEC) from NSF. This
adds ~$5 million/5 years to purchase new equipment and support graduate students.
5
The University of Arkansas was established in 1871 as a landgrant college. The Fayetteville campus is the flagship campus of the
University of Arkansas system and, as the only campus that awards
doctoral degrees in the state, serves as the major center of liberal and
The University
professional education in Arkansas. The campus has eight colleges
and schools: agriculture, architecture, arts and sciences, business, education, engineering, law, and the graduate school. The Department of
Physics is one of twenty departments in the J. William Fulbright
College of Arts and Sciences.
The University of Arkansas,
Fayetteville, offers graduate education leading to master’s degrees in
over 70 fields and doctoral degrees in 24 selected areas.
University of Arkansas: Notable People
A SAMPLE OF FAMOUS ALUMNI
Robert Maurer, class of ‘49 invented fiber optic
technology and was awarded the Presidential
National Medal of Technology.
E. Fay Jones, class of ‘50 recipient of the highest
award in architecture, and studied under Frank
Lloyd Wright.
Pat Summerall, class of ‘53 sportcaster for professional football on the Fox Network.
Jerry Jones, class of ‘65 owner of the Dallas
Cowboys, and member of the National
Championship Razorback football team.
A SAMPLE OF FAMOUS FACULTY
Hillary Rodham Clinton, U.S. Senator from New
York, joined the UA Law Faculty ‘74
Bill Clinton, President of the United States of
America, joined UA Law Faculty ‘73
William J. Fulbright, U.S. Senator from
Arkansas, Founder of the Fulbright International
Exchange Program
Allen Hermann and Zhengzhi Sheng, Physics
Professors discovered thallium-based high-temperature superconductors which held the highest
temperature record for five years.
6
Fayetteville, with a population of 56,000 and located in a
region of great natural beauty, is the cultural center of the Northwest
Arkansas region. It has been ranked by national magazines as
among the top 10 places to live in the U.S.
The city is situated in the heart of the picturesque Ozark
Mountains at an elevation of 1,400 ft. The climate is mild with
extended Fall and Spring seasons. The area provides excellent
opportunities for water skiing, canoeing, hiking, camping, fishing,
and other outdoor activities.
Fayetteville
and
As the cultural center of the northwest region of the state,
which has a population of about 300,000, Fayetteville offers a wide
selection of music, theater, and arts. The University produces many
Environs
plays throughout the year, and many visiting artists perform in its
fine arts concert series. The Walton Arts Center - the center for performing arts - features a constant schedule of symphony performances, theater (including Broadway shows), dance, and art
exhibits.
For the sports enthusiasts, the university has nationally
ranked intercollegiate sports teams and many games are nationally
televised.
Fayetteville is served by over 150 restaurants (from fast food
to ethnic and fine dining), several shopping areas (including the
largest enclosed mall in the region), and five airlines (American,
Delta, Northwest, U.S. Air, TWA). with direct flights to St. Louis,
Dallas, Chicago, Memphis, Atlanta, Los Angeles, North Carolina,
and New York.
7
Research in Progress
The following pages describe the current
research projects in progress in the Department
arranged by categories in these fields:
• Lasers and Optics
(page 9)
• Condensed Matter Physics
(page 18)
• Theoretical Physics
(page 23)
• Physics Education
(page 31)
• Astronomy
(page 31)
Research in Progress
9
Quantum optics, photon statistics, nonlinear
optics, atomic physics, optical pulse propagation,
laser
spectroscopy,
photothermal
and
photoacoustic spectroscopy, and optical data
storage.
Lasers and Optics
Faculty
• Salamo
(page 10)
• Xiao
(page 12)
• Henry
(page 14)
• Singh
(page 15)
• Gupta
(page 16)
• Gea-Banacloche
(see Theoretical Physics, page 25)
• Vyas
(see Theoretical Physics, page 26)
• Oliver
(see Condensed Matter, page 21)
• Ding
(page 17)
Lasers and Optics
10
MAKING CRYSTALS, SEMICONDUCTORS, AND
PHOTONIC DEVICES
Gregory Salamo
University Professor
501-575-5931
salamo@uark.edu
Fellow, Optical Soc. of America,
2000
Alumni Distinguished Service
Award for Research, 1994.
Ph.D. City University
of New York, 1973.
Research Associate, University of
Rochester, 1973 - 1975.
Assistant Professor to
University Professor, 1975 - 1995.
Professor Salamo’s interest is
in quantum optics, nonlinear
optics, photo-refraction and optics
of nano-structures. He has been
featured in PBS documentary
“Science is golden” (1998), and
his research has been featured in
Business News (1994), Science
News (1994) and Optics News
(1993, 94, 97).
When you focus a light beam down to a small spot in a crys tal to the size of a few microns, it then rapidly expands and diverges
to a much greater diameter, right? No! Shown in Fig. 1 is a top view
picture of a light beam focused to a small size at the entrance face of
a crystal. After entering the crystal, it is seen expanding. However,
after inducing its own waveguide in the crystal, the second picture
demonstrates that moments later the beam is trapped and a small
optical wire is created from one end of the crystal to the other. One
can envision as an application a set of optical fibers connected to a
second set of fibers through a crystal. Each beam can be deflected
from any incoming fiber to any outgoing fiber without spreading. A
second application will have two electronic chips talking to each
other via optical wires. Since these self-induced waveguides are
erased as a new optical beam enters the crystal and passes over the
same region, the optical interconnects are reconfigurable. Currently
we are using semiconductor InP and the ferroelectric insulator SBN
as crystals for our investigations. Using our new crystal growth
facility we are exploring new materials which can be used as substrates for photonic-electronic circuits using these optical interconnects. This work is in collaboration with Hongxing Meng and Scot
Hawkins, graduate students at Arkansas, David Bliss of Hanscom Air
Force Base, and Moti Segev of Princeton University.
Is it possible to redesign crystal structure after growth? Yes!
Shown in Fig. 2 is a picture of a crystal with microvariation in its ferroelectric domains. The periodic variation in the domain planes,
seen below, then results in a crystal behavior with periodic electrical
and optical properties. In this case the periodic domain reversed
planes were produced starting with a uniform material and then writing optical holographic gratings which created the modulated material. Our vision is to develop micro-structure devices using domain
programming written by a laser beam. Using our crystal growth
facility and our experience in ferroelectric programming, we have a
unique opportunity to develop the next generation of nano-ferroelectric devices. For example, we have recently made permanent 10
micron waveguides in the middle of a large crystal. In fact, we have
formed and made permanent 10 micron Y-junctions. This opens up
the possibility of a new technology of 3-D optical wiring throughout
a crystal. This work is in collaboration with Matt Klotz, a graduate
student at Arkansas, and Steve Montgomery of the Naval Academy.
Lasers and Optics
11
Is it possible to store a library of 3-D images in a small crystal? Yes!
Holography is a common technique used to generate realistic threedimensional (3D) images. Photorefractive crystals are an ideal storage medium for recording holographic images because of the following advantages: real-time exposure and display, a simpler
recording process in which no pre-or post-processing is required,
low writing beam powers, and a potentially large storage volume.
Our recent experiments have clearly demonstrated the potential of
photorefractive crystals for storage and retrieval of 3D images. In
fact, we have demonstrated the storage and retrieval of 3D color
holograms in a photorefractive crystal. The 3D image closely reproduces the actual colors of the object. The 3D hologram is visible
over a wide perspective as demonstrated by moving one’s head back
and forth while viewing the hologram. The wide field-of-view of the
hologram is also demonstrated using an imaging lens with a color
CCD camera mounted on a goniometer to record various perspectives. The picture below (Fig. 3) shows different perspective views
of a hologram stored in a crystal. Our new experiments are aimed at
demonstrating angle and wavelength multiplexing of many 3-D
color images as well as making the storage permanent. This research
is in collaboration with Christy Heid, Brian Ketchel, and Gary Wood
of the Army Research Laboratory, and Rich Anderson of the
National Science Foundation.
Can we build semiconductors one atom at a time? Yes!
Using a new molecular beam epitaxy (MBE) machine, made possible by a grant from NSF-EPSCoR, we are today building semiconductors one atom at a time and watching where these atoms are
going using a scanning tunneling microscope (STM). In particular,
we are building new broadband infrared sensors by constructing
complex quantum well structures and are exploring new condensed
matter “two-level atoms” by growing quantum dots. The tiny dots
have controllable conduction band energy levels with long dephasing times, allowing us the opportunity to carry out coherent optics
type experiments. Fig. 4 shows a typical quantum dot structure. The
dot is only 20 nm round and 5 nm high. Because of it’s small size,
the dot structure will make novel optical and electronic devices.
This research is in collaboration with Omar Manasreh of Kirtland
Air Force Base.
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Lasers and Optics
12
FUNDAMENTALAND APPLIED RESEARCH IN
QUANTUM AND NONLINEAR OPTICS
We are studying quantum and nonlinear optical properties in
the interactions between laser fields and media, which include
multi-level atomic systems, nonlinear crystals, and semiconductor
nanostructures. In these experimental and theoretical studies, we can
discover interesting fundamental physical properties and find potential applications in making better opto-electronic devices. We are
currently pursuing the following research directions:
Min Xiao
Professor
501-575-6568
mxiao@uark.edu
NSF Young Investigator
Award, 1994.
Alumni Distinguished Service
Award for Research, 1998.
Ph.D., U. Texas, Austin, 1988
Postdoctoral Associate, M.I.T.
1988-1990.
Assistant Professor to
Professor, 1990-98.
Professor Xiao did his Ph.D.
research under Professor Jeff
Kimble (now at Cal Tech) and
joined the University of Arkansas
in 1990. He has published extensively in experimental and theoretical quantum optics, laser physics,
nonlinear optics, and atomic
physics. His research projects are
currently funded by the National
Science Foundation and the Office
of Naval Research.
(1)
Electromagnetically induced transparency (EIT) and its
applications in multi-level systems. When coherent electro-magnetic fields interact with multi-level atomic systems, coherence between
levels is induced. This atomic coherence is essential in creating
novel effects, such as EIT, lasing without inversion, enhanced dispersion without absorption, slowing down the speed of light, and
enhancing nonlinear optical efficiencies. We have experimentally
demonstrated the EIT effects with cw diode lasers in three-level
rubidium atomic systems in two-photon Doppler-free configurations.
We have measured dispersion properties of the EIT systems, slowed
down the speed of light, and demonstrated the enhancement of efficiency of nonlinear optical processes. We studied EIT-related effects
inside an optical cavity and showed a substantial cavity-linewidth
narrowing as the result of EIT. These coherence and quantum inference effects in multi-level systems will have practical applications in
the photonic devices in solid materials (such as semiconductor nanostructures and optical crystals) and we are working on such interesting applications.
(2)
Precision measurements beyond the shot-noise limit. In nonlinear interactions between electromagnetic fields and media, one
can manipulate the quantum fluctuations in the system to suppress
quantum noises in one quadrature of the field, such as to create certain kind of quantum states of light. These quantum states of light
can be used to improve measurement precision beyond the standard
shot-noise limit. Recently, we have generated such quantum states of
light in cw diode lasers and short (100 fs) laser pulses and employed
them to demonstrate subshot-noise detection of small coherent signals by using novel configurations. Many other practical applications (such as in optical communication and laser Doppler radar) of
quantum states of light are currently under investigation.
Lasers and Optics
13
(3) Optical properties and novel devices of semiconductor
nanostructures Semiconductor nanostructures (such as quantum
wires, quantum rods, and quantum dots) have recently attracted
much attention due to their fundamental properties and potential
applications. Quantum dots behave, in many aspects, like atoms. As
the sizes of nanocrystals decrease, the relative quantum fluctuations
increase and become more important. We have observed spectral
images from single quantum dots/rods and studied their emission
and excitation polarization properties. We are interested in the quantum fluctuations of such small systems, especially with quantum
nanocrystals inside micro-optical cavities. We are developing practical photo-electronic devices for optical communication and optical
computing.
(4) Optical communication. Due to the high demand in bandwidth
for data transmission, communication capacity has to be greatly
increased in the next few years. Technologies in optical communications, such as time-division multiplexing (TDM) and wavelengthdivision multiplexing (WDM), need continuous improvements,
which will impose high demands for better system designs and
improved optical components, such as lasers, amplifiers, filters, and
fast modulators. We are currently working on simulating fiber transmission system performance via dispersion and nonlinearity management, building optical components (such as fast modulator, filter,
amplifier, and nonlinear frequency converter), designing better optical components with improved functionality by using novel concepts
developed in our fundamental studies, and studying noise properties
in optical communication systems.
(5) Other applied projects. Other than the above mentioned basic
research directions, we have carried out several applied projects in
the past few years. These projects include improvements of frequency stabilization of semiconductor diode lasers, frequency locking of several diode lasers for optical communication, fast switching
of a diode laser, variable-linewidth laser source, optical tweezers for
biological applications, and detection of contaminants in food products. We will continue to identify and work on new and interesting
practical problems in the future.
Lasers and Optics
An optical tweezer is being used
to study biologically important
molecules in Professor Xiao’s
laboratory. In an optical tweezer
the molecules are trapped in a
laser beam.
14
NONLINEAR OPTICS OF THIN FILMS
We are studying nonlinear materials and systems for use in
novel photonic devices. These devices include image processors,
multiplexers, optical switches, optical modulators, and optical logic
gates. These devices are all presently electronic devices. However,
optical counterparts have advantages over the electronic devices.
These advantages include increased speed and higher component
densities and efficiency. They are similar to the advantages of
replacing copper cable with fiber optical cables in the communications industry.
Michael Henry
Assistant Professor
501-575-8608
henry@uark.edu
Ph.D., Alabama A&M
University, 1994
Dr. Henry’s research is motivated by applications in telecommunication and computing. His
research has possible applications
in signal modulation, multi-plexing and optical logic.
There are several techniques used in our lab to identify and
characterize nonlinear materials. The principal techniques are four
wave mixing, self phase modulation, and third harmonic generation.
In order to characterize and efficiently utilize the material, the nonlinear systems and processes that occur in them must be fully understood. To this end we are carrying out studies of various nonlinear
effects such as quantum stokes confinement, saturation absorption,
and excited state absorption all of which take place in the materials.
Once the materials have been identified and characterized,
the materials are used in systems to investigate their potential for
novel photonic devices. Presently, we are working with dye doped
organic thin films and multiple quantum well thin films. These films
are being tested in image processing and logic systems.
The effects of distributed feedback on the nonlinear processes taking place in the materials is also under study. This work should
give a clear understanding of the nonlinear process that take place in
thin films.
The tools used in our endeavors are an argon ion laser, a
Nd:YAG laser, a diode laser, a lock-in amplifier, a 500 MHz digital
oscilloscope, a micropositioner system and a monochromator. Most
of this equipment is interfaced to either a 166 MHz Dell PC or a 100
MHz Power Macintosh running Labview.
Lasers and Optics
15
QUANTUM OPTICS
Studies of nonlinear dynamics and quantum and classical
coherence are being carried out in a variety of systems in quantum
optics. These systems include lasers and nonlinear optical parametric processes such as second harmonic generation and frequency
down-conversion. In nonlinear dynamics we have been studying the
response of class-B lasers when either the pump or the loss of the
laser is modulated. Such systems are capable of exhibiting an interesting sequence of bifurcations involving transitions between multiple steady-states, oscillatory states and even chaotic states, depending on the depth and frequency of modulation and the number of
modes in the laser. Current experimental efforts are focused on the
Ti-sapphire laser, semiconductor lasers, and intracavity second harmonic generation. These studies of non-linear dynamics have potential for application in laser pulse crafting. For example, carefully
crafted waveforms containing time-delayed pulses of different frequencies can be generated for use in time resolved studies of atomic
dynamics.
We are also investigating the coherence properties of light
generated in optical parametric processes by means of photo-electric
counting techniques. These experiments explore the boundary
between classical and quantum worlds. Our current interest is
focused on nonclassical effects such as nonclassical conditional
interference, squeezing, photon anti-bunching, and sub-Poissonian
photon statistics in second harmonic generation, parametric oscillators, and other dissipative quantum optical systems. Experimental
investigations of nonclassical counting distributions, nonclassical
intensity correlations in the homodyne detection of light, and subPoissonian photon statistics are underway. The results of these
experiments can only be understood quantum mechanically. We are
also developing new photodetection techniques based on two-photon
absorption of light. These techniques allow us to explore certain
higher order photon correlations of microcavity semiconductor
lasers which have not been measured with conventional techniques.
A variety of experimental techniques relying on fast photon counting
and correlation equipment are in use. Nonlinear crystals, carefully
designed optical cavities, He:Ne, semiconductor, Ar-ion lasers, an
Ar-ion pumped Ti-Sapphire laser, transient digitizers, a host of other
state-of-the-art electronic instruments, and several personal computers are available for these experiments.
Lasers and Optics
Surendra Singh
Professor and Chair of the
Department
501-575-5930
ssingh@uark.edu
Ph.D., University of
Rochester, 1982.
Assistant Professor to
Professor, University of
Arkansas, 1982-92.
Chair of the Department
1995 - to date.
Visiting Fellow, Joint
Institute for Laboratory
Astrophysics (JILA),
University of Colorado,
1989-90.
Professor Singh joined the
University of Arkansas in 1982,
shortly after completing his
dissertation under Professor
Leonard Mandel. Although primarily an experimentalist, he is
equally apt at theory. He has
done extensive work on quantum
and classical noise in lasers, and
nonlinear and quantum optics.
16
PHOTOTHERMAL SPECTROSCOPY
IN A COMBUSTION ENVIRONMENT
Combustion is a very complicated phenomenon. The burning of even a simple hydrocarbon involves several hundred coupled
chemical reactions. For this reason, a thorough understanding of the
combustion process does not yet exist. Besides the intrinsic interest
in understanding the physics and chemistry of this prevalent natural
phenomenon, an understanding of the combustion would presumably lead to the design of highly efficient and/or nonpolluting
engines.
Rajendra Gupta
Professor
501-575-5933
rgupta@uark.edu
Fellow, American
Physical Society
Ph.D., Boston U., 1970.
Research Associate, 1970-74,
Assistant Professor, 1974-78,
Columbia University.
Assistant Professor to
Professor, University of
Arkansas, 1978-85. Chair of
the Department, 1989-95.
Visiting Fellow, Princeton
University, Fall 1998.
Editorial Board
Spectroscopy and Spectral Analysis
(China), 1991-to date.
Books edited: Laser Spectroscopy
(AAPT, 1993).
Professor Gupta’s interest
is in atomic physics and laser
spectroscopy. He did extensive
work in high-resolution
(Doppler-free) spectroscopy of
alkali-metal atoms before his
interests shifted to photoacoustic
and photothermal spectroscopy.
The theoretical models of combustion, in general, need to be
experimentally verified, and, at times, even to build a theoretical
model one needs the experimental data. Hence there is a need for
diagnostic techniques, and in general one is interested in measurements of majority (such as H2O, CO2) and minority species (such as
OH, CH, NO, etc.) concentrations, local temperatures, and flow
velocity. Over the past several years we have demonstrated that photothermal deflection spectroscopy is an ideal technique for combustion diagnostics. The technique can be used to measure all three
parameters of interest, that is, species concentration, temperature,
and flow velocity simultaneously using the data obtained in a single
laser pulse. We are engaged in experiments to demonstrate that this
indeed is possible, and will then use this technique to make measurements of several minority species in a variety of flames.
The basic ideas involved in using PTDS for combustion
diagnostics are as follows: A dye-laser beam (pump beam) passes
through the flame. The dye laser is tuned to one of the absorption
lines of the molecules that is to be detected, and the molecules
absorb the optical energy from the laser beam. Due to fast quenching rates in a flame, most of this energy quickly appears in the rotational-translational modes of the flame molecules. Thus the dye
laser-irradiated region gets slightly heated, leading to changes in the
refractive index of the medium in that region. Now if a probe-laser
beam overlaps the pump beam, the probe beam is deflected due to
the variations in the refractive index of the medium created by the
pump beam. The species concentration, temperature, and the flow
velocity can be derived from the amplitude, width, and the time-offlight of the deflection signal, respectively.
Lasers and Optics
17
Optoelectronic and Nonlinear Optical Nanodevices
Professor Ding’s primary research interests include design
and implementation of nanodevices, optoelectronic and nonlinear
optical devices for generation, amplification, and modulation of tunable and coherent waves in the domains of UV, blue, green, infrared,
far-infrared, THz, and submillimeter.
His eventual goal is to efficiently generate and amplify THz
waves, to implement transversely-pumped counter-propagating optical parametric oscillators and amplifiers, nanodevices, and intersubband lasers based on variety of novel structures and configurations.
On the road to these objectives, he has investigated forward
and backward optical parametric oscillation and amplification, and
difference-frequency generation for efficiently generating and
amplifying terahertz waves in CdSe, GaSe, periodically-poled
LiNbO3 and LiTaO3, and diffusion-bonded-stacked GaAs and GaP
plates. The advantage of using birefringence in CdSe and GaSe is
tunability of the output terahertz frequency. Furthermore, both CdSe
and GaSe can be used to achieve the backward parametric oscillation
without any cavity. On the other hand, in periodically-poled LiNbO3
and LiTaO 3, one can take advantage of large diagonal elements of
second-order nonlinear susceptibility tensor. In the diffusion-bonded-stacked GaAs and GaP plates, quasi-phase matching can be
achieved by alternatively rotating the plates. The advantage of using
coherent parametric processes is possibility of efficiently generating
and amplifying temporarily-coherent and narrow-linewidth terahertz
waves. He has also systematically studied KTiOPO4 crystals for
efficient generation of coherent blue and green light. Furthermore,
he has designed, grown, and characterized GaAs/AlGaAs multilayers for eventually generating tunable and coherent waves in the midinfrared in the presence of a diode laser and/or and erbium-doped
fiber laser. These coherent sources are compact, monolithic, robust
and integrable.
Lasers and Optics
Yujie J. Ding
Associate Professor
yding@uark.edu
Ph.D., John Hopkins University
1990.
Professor Ding’s primary
research interests include design
and implementation of
nanodevices, optoelectronic and
nonlinear optical devices for
generation, amplification, and
modulation of tunable detection,
incoherent and coherent waves in
the domains of UV, blue, green,
mid-infrared, far-infrared, THz,
and submillimeter.
18
Computational Physics, Raman Brillouin and
dynamic light scattering, high-pressure
physics, crystal growth, ultrasonics, the
physics of novel magnetic materials, and
growth and characterization of semiconductor
heterostructures.
Condensed Matter
Faculty
• Thibado
(page 20)
• Oliver
(page 21)
• Filipkowski
(page 22)
• Salamo
(See Laser and Optics, page 10)
• Ding
(see Laser and Optics, page 17)
• Bellaiche
(see Theoretical Physics, page 29)
Condensed Matter
19
20
SURFACE PHYSICS
Devices based on III-V compound semiconductors (e.g.,
GaAs, InP, GaN, etc.) have fueled the growth of the multi-billion
dollar telecommunications industry, making possible such technologies as fiber-optic communications, cellular phones, direct broadcast
satellite TV, and global positioning systems. Unlike silicon-based
devices, which are produced primarily by ion implantation techniques, the III-V device structures must be formed by depositing one
plane of atoms after another until the entire structure is grown.
Necessarily, III-V device fabrication occurs solely at a semiconductor surface. The better one can control and manipulate the motion of
atoms on surfaces, the more sophisticated the devices structures one
can make. In order to better understand the surface processes important to device fabrication, we have combined, for the first time, the
state-of-the-art in III-V [(Al,Ga,In)-(As,P)] structure growth using
molecular beam epitaxy (MBE) with the powerful atomic-scale surface characterization of scanning tunneling microscopy (STM).
Paul Thibado
Associate Professor
501-575-7932
thibado@uark.edu
NSF CAREER Awardee
Ph.D., University of
Pennsylvania, 1994.
NRC Post-doctoral Fellow,
Naval Research
Laboratory, 1994-96.
Professor Thibado’s primary
research interests are to study the
physical properties of small structures on technologically important
semiconductor surfaces. This
includes atomic diffusion, spindependent tunneling, and optical
properties. To achieve this, he has
combined the state-of-the-art in
device fabrication using molecular
beam epitaxy (MBE) with the
powerful atomic-scale characterization capability of scanning tunneling microscopy (STM).
Our current research interests can be conveniently classified
into two areas. First, by taking STM images of a growing surface
and using simple counting algorithms we can learn about the fundamental processes of growth: adsorption of new atoms on surfaces,
single atom diffusion, nucleation of atoms into stable islands, and the
growth of existing islands. Second, by replacing the normal metal
STM imaging tip with a ferromagnetic metal, we can study the spindependent tunneling properties of the electron at the scale of an
atom. In particular, we can identify which atomic-scale structures
efficiently scatter the electron’s spin. This project is geared toward
the development of a new transistor which utilizes both the charge
and spin of the electron to yield novel electronic properties.
As devices continue to shrink, conventional characterization
techniques are increasingly ineffective in identifying factors relevant
to device failure. However, since the invention of the STM, individual atoms may be viewed on a wide variety of systems and surfaces. Through the unique combination of MBE device growth and
STM characterization, significant progress in the development of
next generation devices can be achieved.
Condensed Matter
21
CONDENSED MATTER UNDER
EXTREME CONDITIONS
We are exploring both static and dynamic properties of interesting condensed matter systems at very high pressures using diamond anvil cells (DACs). In particular we are interested in transitions between different phases of matter as temperature (T), pressure
(P), and applied fields are varied. With appropriate furnaces and
cryogenic equipment we can do combined T- and P-dependent studies. Several optical techniques such as Raman, tandem Brillouin,
dynamic light scattering (DLS) and ruby fluorescence are used to
probe materials under these extreme conditions.
A primary goal is to deepen our understanding of the mechanisms underlying the liquid to glass transition. This is currently a
topic of intense interest for both fundamental and technological reasons. As a liquid melt is supercooled to the glassy state, its viscosity and structural relaxation time increase by up to 17 orders of magnitude, requiring several techniques to probe this enormous range in
dynamical behavior.
By combining T- and P-dependent Brillouin scattering we
can probe the low-viscosity (high-T or low-P) limit where relaxation
times are short (~10-12s). As the glass transition is approached at low
T or high P, however, relaxation times approach experimentally long
times and lower frequency probes such as DLS are needed. A current goal is to combine this technique with DACs to explore low frequency glass transition dynamics at high pressure.
We are also studying glassy behavior in magnetic spin-glass
systems using a Quantum Design SQUID instrument. In particular,
we are exploring the intriguing paramagnetic (PM) to ferromagnetic
(FM) to reentrant PM to spin-glass sequence of transitions in the
binary alloy Fe0.7Al0.3, as well as FM to spin-glass transitions in
ternary Fe1-xAl0.3Mx alloys where M=Co, Mn, Ti, V. High-P studies
of unusual reentrant behavior in oxide ferroelectric materials are also
in progress.
This research is supported by several grants from the NSF.
We also have an active collaboration with the Exxon Research and
Engineering Company, where world record high-P viscosity measurements have been achieved.
Condensed Matter
William F. Oliver III
Associate Professor
501-575-6571
woliver@uark,edu
Master Teacher Award, 2001
NSF CAREER Awardee
Ph.D. University of
Colorado, 1988.
Research Associate, Arizona
State University, 1988-92
Assistant Professor to
Associate Professor,
U of Arkansas, 1992-98
Visiting appointments at Los
Alamos Nuclear Scattering
Center and Exxon Corporate
Research Laboratory.
Professor Oliver studies the thermodynamic, structural, and
dynamic properties of a variety of
hard and soft condensed matter
systems under conditions of high
pressure. He is currently working
on phase transitions in nonlinear
optical materials, the liquid-glass
transition, and magnetic spin-glass
systems.
22
PHYSICS OF NOVEL HETEROGENEOUS
MAGNETIC MATERIALS
With the development of techniques for producing materials not found in nature, a number of new and exciting phenomena
have become available for study in the field of condensed matter
physics. Many of these phenomena are based on magnetism, in
particular the joining of magnetic materials with those which are
nonmagnetic. We study the behavior of heterogeneous condensed
systems in which a magnetic component plays a crucial role. In
essence, magnetism is introduced as a new degree of freedom to
manipulate and to probe dynamics. Our emphasis at this time is on
two very different kinds of systems: metal-semiconductor (MS)
contacts in which the metal is ferromagnetic, and liquid suspensions of small (~1 micron) particles containing a magnetic core. In
the case of the MS structures, we are interested in the dynamical
behavior of electrons, while in the suspensions particle dynamics is
the focus.
Mark Filipkowski
Assistant Professor
501-575-6593
filipkow@uark.edu
Ph.D., University of
Connecticut, 1991.
Post-Doctoral Fellow,
Naval Research Laboratory,
1991-94.
Professor Filipkowski’s main
interest is magnetoelectronics,
i.e. the behavior of spin-polarized
electrical currents in metals and
semiconductors. He is presently
developing tools, such as nuclear
magnetic resonance, to probe
these currents on the
microscopic scale.
Probing dynamics via magnetism is accomplished using a
number of tools, including magnetrotransport, inelastic electron
tunneling spectroscopy, electron spin resonance and radio frequency permeability measurements. We are particularly interested in
developing new techniques based on nuclear magnetic resonance
(NMR), and have recently purchased a state-of-the-art NMR spectrometer. In MS structures, the injection of spin-polarized electrons
from a ferromagnetic electrode to a semiconductor will result in
dynamical polarization of nuclei as the latter interact with the
polarized electrons. These effects can be used to study the distribution of nonequilibrium electron spin polarization in the semiconductor. The rotational dynamics of suspended magnetic particles is
accessible with the methods of two-dimensional NMR. This is
based on the dependence of the nuclear resonance on orientation
with respect to an external field, and the consequent evolution of
nuclear magnetization with particle rotation.
Condensed Matter
23
Interaction of radiation and matter, squeezed
states, multiphoton processes, chaos, photon
statistics, nonlinear optics, atomic collisions,
quantum field theory, and dynamics and spectroscopy of polyatomic molecules.
Theoretical Physics
Faculty
• Gea-Banacloche
(page 25)
• Vyas
(page 26)
• Harter
(page 35)
• Lieber
(page 28)
• Bellaiche
(page 29)
Theoretical Physics
24
25
QUANTUM CLASSICAL CORRESPONDENCE
Recent research has focused on various aspects of the quantum-classical correspondence problem. To see why this is not trivial, consider, for instance, that there are (infinitely) many more
states possible for a quantum particle than for a classical particle
(e.g., a quantum particle could, fairly literally, be in two different
places at once!). This means that an infinite number of possible
states must disappear in the classical limit. How, then, is the classical dynamics to be recovered from the quantum dynamics?
For macroscopic systems, the answer appears to lie in the
fact that the coupling to the environment (which is unavoidable for
very large systems) destroys very rapidly the coherence between
any macroscopically distinct branches of the wavefunction. Most
nonclassical states and all macroscopically entangled states then
become incoherent mixtures, which can no longer be interpreted as
describing an individual system. This decoherence process would
be the key to the classical limit.
Decoherence would play an important (and destructive) role
in certain devices which have been proposed recently called quantum computers. In a quantum computer, each binary register would
not necessarily have to be in one of the two states 0 and 1, but could
exist in a coherent superposition of the two. Quantum computers
could, in principle, perform certain calculations much faster than
classical computers; however, it is essential that the coherence
should be maintained for the whole duration of the calculation.
Some of the current work is devoted to looking at coherencedestroying mechanisms in quantum computers, and, in particular, at
how these effects scale with the size of the computer and the length
of the calculation.
A recently-completed project is a study of the so-called
quantum chaos problem. Consider a system which, when treated
classically, exhibits chaotic behavior. Does this classical chaos
leave a trace in the mesoscopic quantum world, and, if so, what is
it? It has been suggested that quantum computers could be used to
simulate the behavior of classically chaotic systems. It might be
very interesting to study what one has then. Would the behavior of
the quantum computer be recognizable as chaotic from a classical
point of view, or would the quantum nature of the system inhibit the
chaotic evolution?
Theoretical Physics
Julio Gea-Banacloche
Associate Professor
501-575-7240
jgeabana@uark.edu
Assoc. Editor, Physical Review A
Ph.D., University of New
Mexico, 1985.
Research Associate, Max
Planck Institute for Quantum
Optics, 1985-87.
Staff Scientist, Instituto de Optica,
Madrid, Spain, 1988-90.
Assistant Professor to
Associate Professor, University
of Arkansas, 1990-94.
Julio Gea-Banacloche got his
Ph.D. at the University of New
Mexico working on the quantum
theory of the free-electron laser
under Marlan O. Scully. He has
done theoretical work in laser
physics and quantum optics. He
discovered the internet in 1994
and has spent much of the past
6 years online. You can find out
more about him at his personal
home page;
http://comp. uark.edu/ ~jgaebana.
26
INTERACTION OF SIMPLE ATOMIC SYSTEMS
WITH NONCLASSICAL LIGHT
Research interests are in the areas of quantum optics, nonlinear optics, and laser physics. We are studying the fundamental
nature of light and its interaction with atoms. Light beams produced by an incandescent bulb, a laser, and an atom are different.
An understanding of this difference requires use of the quantum
theory of light. These studies of quantum effects are important not
only fundamentally but also have potential applications in atomic
spectroscopy, optical precision measurements, optical computing,
optical storage, and optical communication.
Reeta Vyas
Associate Professor
501-575-6569
rvyas@uark.edu
Ph.D., State University of New
York (Buffalo), 1984.
Visiting Assistant Professor,
University of Arkansas 1984-89.
Assistant Professor 1989-94.
Associate Professor, University
of Arkansas, 1994.
Visiting appointments at
several universities in Brazil.
Professor Vyas’early work
was in theoretical nuclear physics.
However, her interest shifted to
theoretical quantum optics after
coming to the University of
Arkansas. She has published
extensively in the areas of nuclear
physics, quantum optics, nonlinear
optics, photothermal spectroscopy,
and laser physics.
We have been studying the properties of nonclassical states
generated by nonlinear optical processes such as second harmonic
generation, four-wave mixing, and optical parametric oscillation.
Many of these states have been experimentally realized. We have
developed new techniques to study the statistical properties of these
nonclassical states. An analytic calculation based on this approach
for homodyne detection of light from a parametric oscillator has
revealed a rich variety of quantum effects displayed by this light.
Examples of these quantum effects include antibunching,
subPoisonian statistics, and novel nonclassical correlations, which
are dramatic manifestations of quantum interference and collapse
of the wave function.
Interaction of these nonclassical states with simple atomic
systems allows us to explore regimes which from the start have no
classical analogs. The atom can be in free space or inside an optical cavity. There can be dissipation due to atomic and cavity
decays. Our aim is to understand how the quantum nature of the
atom-field interaction is reflected in the fluctuation and correlation
properties of the scattered light. Practical applications of these will
be in microlasers, which will play an important role in the next generation of highly efficient miniature devices and communications.
We are also investigating squeezing effects associated with
the mechanical motion of an atom trapped in time dependent fields.
We find that in Paul Trap, depending on the strength of magnetic
field, the position or momentum quadrature is squeezed. We find
regions of instability where the variances of both quadratures continue to grow with time. Since an important purpose of trapping
atoms is to minimize the center of mass motion, these studies will
provide a better understanding of any fundamental limits on the
residual particle motion.
Theoretical Physics
27
DYNAMICS AND SPECTROSCOPY OF
POLYATOMIC MOLECULES
Atomic and molecular theory involving symmetry principles and group algebra is one of the specialties for Dr. Harter. This
also involves a lot of computer graphics and animation, a good deal
of which is used in classes.
Dr. Harter and his students were the first to calculate and
predict the form of the rotational and vibrational spectra of the soccer ball shaped Buckminsterfullerene (C60) or “Buckyball” molecule. This was used by experimentalists to help find ways to make
enough ‘Buckyballs’ to prove that this incredible form exists.
Since then the study of C60 and related fullerenes has become a
worldwide industry. A Nobel prize in chemistry was given in 1996
to the experimental chemists who first made minuscule amounts of
C60.
Current work is being done on the symmetry breaking of
C60 by one or more 13C isotopes. A pure 12C60 buckyball is a giant
Bose-symmetric structure or boson with the highest point symmetry that can occur in a molecule. Even a single 13C breaks this symmetry almost completely and a 13C60 molecule would be an incredible Fermi-symmetric structure or Fermion with over an octillion of
nuclear spin states. The first prototypical examples of these effects
were recently observed in simpler molecules SiF4 and SF6.The
effects of 13C and its nuclear spin on fullerenes are being pursued
now.
Another area of research involves using optimal control theory for quantum systems such as rotating molecules. Classical control theory is a well-known engineering discipline, but quantum
control theory is just beginning to be developed. It involves sophisticated and interactive use of computer models and simulations.
Many of the computer simulations are useful for students.
Classroom use of computer simulation is one of the areas Dr. Harter
has been developing since before 1984. Over twenty Macintosh
programs have been developed for student use. Also, his students
are being given state-of-the-art tools for learning to make their own
high-performance interactive simulation programs. (See Physics
Education for details.)
W. G. Harter
Professor
501-575-6567
wharter@uark.edu
Fellow, American Physical
Society.
Master Teacher Award, Fulbright
college of Arts Sciences, 1986.
Ph.D., University of California
at Irvine, 1967.
Research Associate, U.C.
Irving, 1967-68.
Assistant Professor, University
of Southern California, 1968-74.
Associate Professor, Georgia
Institute of Technology,
1978-85.
Books authored: Unitary
Calculus for Electronic Orbitals
Springer, 1996 and Principles of
Symmetry Dynamics and
Spectroscopy, Wiley, 1993.
Professor Harter’s primary
interest is the theoretical studies
of the symmetry and dynamics of
polyatomic molecules.
Theoretical Physics
28
QUANTUM MECHANICAL THREE-BODY PROBLEM
Primary research areas have been quantum electrodynamics, elementary particles and scattering theory, the latter with an
emphasis on three-body problems with applications in atomic
physics.
Michael Lieber
Professor
501-575-6267
mlieber@uark.edu
Ph.D., Harvard, 1967
Associate Research Scientist
and Adjunct Assistant
Professor, NYU, 1967-70.
Assistant Professor to
Professor, University of
Arkansas, 1970-1983.
Chair of Department 1983-86.
Visiting member, Institute for
Theoretical Physics, U.C.
Santa Barbara, 1988.
Vice Chairman of Department
1992 to 1999.
Professor Lieber obtained his
doctorate under the direction of
Nobel Laureate Julian Schwinger.
His current research interests are
in theoretical and mathematical
physics, with particular emphasis
on quantum electrodynamics and
atomic scattering theory.
The three-body problem is famous in both classical and
quantum mechanics, but my research has concentrated on the quantum case. In recent years I have been interested in an anomalous
situation with regard to so-called “capture” reactions, in which an
energetic projectile captures a particle from a composite target, e.g.,
A + (BC) (AB) + C, and “break-up” (or in the atomic case, ionization): A + (BC) A + B + C. An example of capture from
atomic physics would be a proton projectile capturing an electron
from a target atom, emerging as a neutral hydrogen atom. In ionization all three particles would be free. These processes are very
fundamental, and experiments studying them are done in many laboratories around the world. Unfortunately, the theory, even when
pure Coulomb potentials are used (especially when pure Coulomb
potentials are used!), proves to be extremely difficult and many
approximate techniques have been developed. Recently, I have discovered that for certain masses of the three particles, capture is
kinematically forbidden by means of the simplest double collision
process. I am currently studying the possibility of capture by
means of triple collisions when the masses lie in these regions.
Together, with a graduate student we have shown that capture by a
triple-collision process is indeed possible when double collision
capture is not. We are now studying the implications of this for the
quantum mechanical properties of the three particle system.
In the case of breakup reactions involving three charged
particles in the final state, such as ionization of an atom by electron
collision, calculations require accurate approximate wave functions, since no exact ones exist. Important contributions come from
situations where one pair of particles emerges with nearly the same
velocity. I have recently published an improved wavefunction
which is valid in this region, and which goes smoothly into the
wavefunction valid when all three particle are moving apart.
Numerical calculations of the ionization probability and angular
distribution of the ionization products, using this improved wavefunction are in progress, as well as further improvements to the
wavefunction.
Theoretical Physics
29
COMPUTATIONAL CONDENSED MATTER PHYSICS
Electronic-structure methods provide a powerful set of tools
for the design and prediction of material properties. At least two
different methods corresponding to two different system sizes are
technically distinguishable: first-principles calculations vs secondprinciples approaches. First-principles calculations can be used to
investigate systems of normal size (up to 100 atoms) with few-percent accuracy, using only the atomic numbers of the atoms and
some initial guess of the atomic coordinates as input. On the other
hand, “second-principles” approaches have been recently developed to extend the reach of first-principles calculations by investigating properties of large systems (100-1 million atoms). Our
interests are in applying these two electronic-structure techniques
to study properties of technologically important materials.
More precisely, our current research program is divided into
three activities:
• Ferroelectric systems.
A particular project is to design compounds with optimum or new structural, piezoelectric and dielectric properties.
• Semiconductor compounds.
This includes surface and alloying
effects on structural, optical, and electronic properties. In particular, our focus is on the microscopic understanding of optoelectronic materials (III-V and II-VI semiconductors) and bluelaser systems (wide-band gap nitrides).
• High pressure Physics.
Emphasis is placed on pretransitional
effects, i.e., on effects occurring in a crystallographic structure
just before it undergoes a phase transition to another structure.
In particular, we would like to know what detailed mechanisms
are associated with these pretransitional effects.
Modern computational and simulation methods can provide
the fundamental understanding needed for progress in applied
fields such as semiconductor technology, piezoelectric devices, and
material science. As a result, significant advances in the design and
the optimization of properties of complex systems can now be
achieved.
Theoretical Physics
Laurent Bellaiche
Assistant Professor
501-575-2506
laurent@uark.edu
NSF CAREER Awardee
Ph.D. University of Paris
(France), 1994.
Teaching and Research
Associate, University of Paris
(France), 1994-1995.
Post-doctoral Fellow, National
Renewable Energy Laboratory
(CO), 1995-1997.
Research Associate, Rutgers
University (NJ), 1997-1998.
Professor Bellaiche’s
primary interests are the prediction, design and optimization of
properties of semiconductors and
ferro electric materials. He uses
state-of-the-art band-structure
methods to study electronic,
structural, optical, dielectric and
piezoelectric properties.
31
Develop and implement interactive learning
techniques, physics for non-science students,
and computer simulations for physics education.
Physics Education
Faculty
• Stewart
(page 32)
• Harter
(page 33)
• Vickers
(page 34)
Astronomy
Observational astronomy of eclipsing
binaries, spotter stars, and flare stars.
Faculty
• Lacy
(page 35)
Physics Education & Astronomy
32
EDUCATIONAL ENGINEERING
A study of current models for science education, a synthesis of the literature in interactive learning techniques, and my experience in teaching and course management has developed my
research with NSF support along three interrelated lines:
1) Formal Modeling and Measurement of Traditional
Education Processes. Study of current models for science education reveals a lack of scientific method. Our research allows us to
optimize student, instructor and institutional resources and maximize student learning. We will identify cognitive steps that materials should contain or learners should carry out and develop instruments to measure which of those steps are provided and traversed.
This understanding will allow department wide goal setting.
Preliminary results offer explanation of difficulty in transporting
curricular developments. Methodology developed for this research
is general enough to be used at any level of education.
Gay Stewart
Associate Professor
(501) 575-2408
gstewart@uark.edu
Fulbright College
Master Advisor Award, 1998.
Ph.D., University of Illinois,
Urbana-Champaign, 1994.
Dr. Stewart’s Ph.D. dissertation
was in the area of high energy
physics. While a graduate student, she developed a strong
interest in physics education
reform. Since joining the
University of Arkansas, she has
been heavily involved in education research, developing curricula, training of teaching assistants,
and building ties with high school
science teachers.
2) Curriculum Development. Our goal is to develop materials and class strategies that are effective for any size institution.
Course materials have been requested by institutions in the United
States, Korea, and Sweden. Evaluative testing for student understanding and a test bank for E&M are also under development. As
part of the course and curriculum development grant, we are working on preparing graduate students to join the professoriate and
developed a departmental TA training program. This program has
grown into a program for Preparing Future Physics Faculty (PFPF).
The PFPF program is sponsored jointly by the NSF, the American
Association of Physics Teachers, the Association of American
Colleges and Universities, and the Pew Charitable Trusts. The
University of Arkansas PFPF, directed by Dr. Stewart is one of four
pilot sites nationwide.
3) Building the Tools and Putting It All on the Web. We
need standard models and measures of efficiency and quality to
identify missing, inefficient, and truly innovative pieces of material. Such a system of modeling and published standard models will
allow iterative improvement of experimental materials before they
are shown to the student. As an education researcher I create materials, but as an educator I am bothered by the need to use my students to initially test those materials. Building these models and
developing and maintaining all the models, instruments, and measurements in searchable/downloadable form on the WWW for use
by the entire physics community is the current emphasis of our
research.
Physics Education and Astronomy
33
COMPUTER SIMULATIONS
Classroom use of computer simulation is one of the areas
Dr. Harter has been developing since before 1984. Over twenty
Macintosh programs have been developed for student use. Also,
his students are being given state-of-the-art tools for learning to
make their own high-performance interactive simulation programs.
Learn It consists of a “library” of fifteen or twenty “userfriendly” graphical animation programs. Some of these are
described in a feature article in Computers in Physics (Sept. 1993).
They have been used as classroom demonstrations by instructors
and laboratory projects for students in a wide range of classes at a
number of universities and colleges in the U.S. and Europe. They
contain powerful and intriguing lecture demonstrations, but they
minimize arcane aspects of computer which would otherwise interfere with teaching or learning.
Code It consists of “trees” of different programming shell
projects each with a multitude of powerful simulation tools in the
form of C++ source code. They provide students with an “industrial strength” development environment equal to or better than that
currently available.
Physics Education and Astronomy
W. G. Harter
Professor
501-575-6567
wharter@uark.edu
Fellow, American
Physical Society.
Master Teacher Award, Fulbright
College of Arts Sciences, 1986.
Over the past ten years, Dr.
Harter has undertaken two major
projects to improve the teaching
of physics using computer animations, simulations, and demonstrations. The first project called
Learn It is for non-programmers
and computer neophytes, while
the second and more recent project Code It is for students beginning to learn the art of scientific
simulation programming.
34
MICROELECTRICS-PHOTONICS
This interdisciplinary graduate program was defined to
include science, engineering, and business aspects of advanced
microelectronics-photonics devices. This true interdisciplinary
graduate degree program, offers both MS and PhD degrees in
Microelectronics-Photonics (microEP). The program operates as a
virtual department that reports directly to the Dean of the Graduate
School, with a faculty that spans multiple departments from both
the Fulbright College of Arts and Sciences and the College of
Engineering. MicroEP is very flexible in considering applicants
from a wide range of undergraduate degrees.
Ken Vickers
Research Professor and Director
of the microEP Graduate Program
(501) 575-2875
vickers@uark.edu
MS Physics, University of
Arkansas, 1977.
Integrated Circuit Processing,
Texas Instruments, 1977-1998
Engineering Manager,
Texas Instruments, 1991-1998
Professor and Director of the
microEP Graduate Program,
University of Arkansas,
1998-to date
Professor Vickers joined the
University of Arkansas in 1998.
After completing his MS degree
in Physics in 1977, he was
employed by Texas Instruments in
integrated circuit process and
equipment engineering. During
these twenty-plus years of
employment, he worked a year in
Freising, Germany; chaired
worldwide factory teams on various iniatives; and spent the last
seven years as engineering manager for the highest volume
Integrated Circuit fabrication factory in the world, located in
Sherman, Texas.
Students in the microEP graduate degree program follow a
matrix reporting structure that is unusual in the University environment but common in the industrial environment. Each student has
a traditional relationship with their research professor and that
research group. But all students that enter the microEP program in
a given academic year also report to the program director as a pseudo-industry engineering group, a group that gathers in a weekly
operations meeting to create and exercise the soft skills that will
make them highly effective in their early careers after graduation.
I encourage any students that are interested in these degrees
to contact me or visit the microEP web site at
www.uark.edu/depts/microep. My primary measure of success of
our university is our students’ effective use of their education in a
rewarding career of their choice after graduation. Working with
students to understand if microEP programs will support their
career goals after graduation is the first step in improving my measure of success of the University of Arkansas.
In 1999, a degree was created within the Department of
Physics to support Physics graduates interested in advanced
physics studies, but also interested in diversifying their coursework
at the MS level into applied physics or engineering arenas. This
MS in Applied Physics is a degree designed to (1) create a highly
marketable physics degree upon graduation while (2) fully preparing its graduates to enter the University of Arkansas PhD program
in Physics.
Dr. Greg Salamo and I have now been funded through the
Department of Education FIPSE program to bring the microEP
educational methods into the Physics graduate curricular.
Beginning in June 2001, new Physics graduate students will form
the Physics Cohort 1 group.
Physics Education and Astronomy
35
ECLIPSING BINARIES
My current research centers on the theory of stellar evolution, especially on methods of testing the validity of its details. I
am working as part of an international collaboration to determine
accurate fundamental astrophysical data about stars in eclipsing
binary and multiple star systems. The types of data we are able to
provide include orbital parameters, masses, radii, luminosities, and
internal structure of the stars. In order to obtain these data, we need
to measure both the brightness as a function of time (the light
curve) of the eclipsing binary and the radial velocities of both stars
as a function of time (the RV curve). It is possible to measure light
curves of these eclipsing binaries with a relatively small telescope.
For this purpose we are using telescopes in Chile and at the
University of Arkansas. Radial velocities are derived from spectra
which must be obtained with larger telescopes. Telescopes at
McDonald Observatory in Texas and at Kitt Peak National
Observatory in Arizona have been used in an ongoing program to
obtain digital spectra of our program stars. Radial velocities are
extracted from the spectra with main-frame computers on campus.
Numerical models can be fitted to the photometric and spectroscopic data to derive fundamental astrophysical parameters such as
the masses and radii of the stars. We can often measure these data
to an accuracy of 1% or better, and new techniques promise to
improve this accuracy to much higher levels, perhaps to better than
0.1%. At this level of accuracy the observations can serve as a critical test of theories of stellar evolution — theories which cannot
match the observations must
be rejected. Our efforts are
directed to the task of testing our current theories at
the highest levels of
accuracy attainable.
Claud H. Sandberg Lacy
Professor
501-575-5928
clacy@uark.edu.
Edith J. Woodward Award of the
American Astronomical
Society, 1993.
Ph.D., University of Texas
at Austin, 1978.
Visiting Assistant Professor,
Texas A&M University,
1978-80
Assistant Professor to Professor,
University of Arkansas,
1980-1999.
Professor Lacy’s primary
research interest is in studies of
eclipsing binary stars. He has
made numerous observing runs
at McDonald Observatory, KittPeak National Observatory, and
Cerro Tololo Interamerican
Observatory (Chile).
The URSArobotic telescope
at Kimpel Observatory,
University of Arkansas
Physics Education and Astronomy
36
Professors Emeritus
Raymond Hughes, University Professor - Atomic Physics
and Surface
F.T. Chan, Professor - Condensed Matter
Physics
Charles Richardson, Professor - Atomic Physics and
Thermodynamics of Aerosols
Art Hobson, Professor - Physics Education
Otto Zinke, Professor - Plasma Physics
Don Pederson, Professor - Condensed Matter Physics
and Vice-Chancellor for Finance and Adminstration
37
Departmental Staff
Jean Eaton, Office Manager
Shari Whitherspoon, Administrative Assistant
David R. Coffey, Secretary, Physics Library
Stephen R. Skinner, Instructional Equipment Curator
Brandon Rogers, Master Machinist
38
THE GRADUATE PROGRAM*
I.
ADMISSION REQUIREMENTS
Prospective students must satisfy the requirements of the Graduate School as described
in the Graduate School Catalog and have the approval of the Graduate Admissions Committee
of the Department of Physics. In addition, to be admitted to graduate study in physics without
deficiency, candidates should have an undergraduate degree with the equivalent of a 30-hour
major in physics including intermediate level courses in mechanics and electricity and magnetism, and mathematics through differential equations.
Prospective students from foreign countries in which English is not the native language
must submit TOEFL scores of 550 or above. To receive an Assistantship for which the duties
include teaching, the student must score 50 or more on the Test of Spoken English.
II.
DEGREES OFFERED AND REQUIREMENTS
Ph.D.
This program is designed for students interested in working in either an academic environment or an industrial environment. The student must complete a minimum of 40 semester
hours in graduate courses. In addition, a student must pass awritten and oral candidacy exam,
earn 18 hours of credit in Doctoral Dissertation, submit a dissertation, and defend it successfully
in a comprehensive oral examination given by the advisory committee.
M.S. Physics
The program is designed for students interested in working in an academic environment.
The degree program requires 31 semester hours, of which 9 hours can be courses taken in other
departments.
M.S. Applied Physics
This program is designed for students interested in working in an industrial environment.
The degree program requires 31 semester hours, of which 9 hours can be courses taken in other
departments.
M.A. Physics Education Concentration
This program is designed for in-service secondary school teachers or students interested
in teaching physical sciences in Community Colleges. The degree requires 30 semester hours of
graduate work. Prospective candidates for the Master of Arts degree-Education concentration are
expected to have earned credit in courses equivalent to PHYS 2054, 2074, 3614, and 3113.
39
III.
TYPICAL COURSE CURRICULUM
Ph.D. Candidates
First Year
Fall:
Summer:
Second Year
Fall:
Summer:
Third Year
Fall:
Summer:
Introduction to Research
Mathematical Methods I
Quantum Mechanics I
Research Full Time
Spring:
Research Techniques I
Adv. Electromagnetic Theory
Quantum Mechanics II
Research Techniques II
Advanced Mechanics
Quantum Optics
Research Full Time
Spring:
Research
Atomic & Molecular Physics
Thesis
Research
Statistical Mechanics
Thesis
Research Full Time
Spring:
Research
Solid State Physics
Thesis
Introduction to Research
Mathematical Methods I
Quantum Mechanics I
Research Full Time
Spring:
Research Techniques I
Adv. Electromagnetic Theory
Solid State Physics
Research Techniques II
Electives
Thesis
Research Full Time
Spring:
Research
Electives
Thesis
M.S. Physics and Applied Physics Candidates
First Year:
Fall:
Summer:
Second Year:
Fall:
Summer:
M.A. Physics Education Concentration Candidates:
Tailored to individual needs by advisor after a student interview.
40
A few typical careers chosen by our recent graduates
The education our graduate students receive and the analytical and creative skills they
acquire lead them to a variety of interesting careers in academia, government, and industry. The
following list gives the organizations where some of our recent graduates are employed and, if
known, the positions they hold.
Dorel Guzen, Ph.d. 2000, Research Engineer, Corning Corp., Corning, NY
William Burkett, Ph.D., 2000, Staff Scientist, Extera Corp., Dallas, TX
Tim Burt, Ph.D., 1999, Staff Scientist, Ratheon Corp., Dallas, TX
Matt Klotz, Ph.D., 1999, Staff Scientist, Micro-Machines Corp., Los Angeles, CA
Scott Hawking, Ph.D., 1999, Post-Doctorate, University of Iowa, Iowa City, IW
Michael J. Schillaci, Ph.D., 1999, Assistant Professor, Francis Marion University, Florence, SC
Sergio Afonso, Ph.D., 1997, Senior Process Development Engineer, Honeywell Microswitch.
Kaiyuan Chen, Ph.D., 1997, Senior Product Engineer, Texas Instruments, Dallas, TX
Kim Fook Lee, M.A., 1997, Ph.D. Student, Duke University
Zheng Lu, Ph.D., 1997, Engineer, MEMC Electronic Materials Inc., St. Louis, MO
Gregory Fox, M.S., 1996, E-Systems, Dallas, TX
Patrick Holmes, M.A., 1996, Law School, Purdue University
Henry Leach, M.S., 1996, Fidelity Investments, Cincinnati, OH
T.C. Reimer, Ph.D., 1996, Business Analyst, WalMart Headquarters, Bentonville, AR
John Shultz, Ph.D., 1996, Research Associate, High Density Electronics Center, Univ. of AR
Galen Duree, Ph.D., 1995, Associate Professor, Northwest Nazarene College, Nampa, ID
Greg Finney, Ph.D., 1995, Associate Professor, U. S. Air Force Academy, Colorado Springs.
Qifang He, Ph.D., 1995, Assistant Professor, Arkansas State University at Beebe, Beebe, AR
Shaozheng Jin, Ph.D., 1995, Telecomm Canada, Ottawa, Canada
Matthew Morin, M.S., 1995, Actuarial Assistant, American State Insurance, IN
Changxin Wang, Ph.D., 1995, McDonald Associates, Dallas, TX
William Kiehl, Ph.D., 1994, Systems Engineer, Ball Aerospace, CA
Yujiang Qu, Ph.D., 1994, Member, Technical Staff, British Telecommunications, Wash., DC
A few comments by our current graduate students about graduate studies at
Arkansas
“At Arkansas I am becoming the physicist I want to be. In part this is due to the
example of the faculty who are at the same time excellent researchers and inspiring
teachers. In part this is due to the openness and friendship of the graduate students,
both in and out of the classroom. Taken together these two reasons have made graduate study here both pleasurable and productive.”
~ Tim Burt
“I chose to come here because I had heard “horror stories” about being lost in
the masses at the larger universities. I talked with Dr. Salamo and he told me that I
would be very happy with the size of the classes and the amount of personal attention
that a student can receive. In this regard I have been very happy here at Arkansas.”
~ Michael J. Schillaci
Additional Resources and Facilities
The Physics Library is located in the
Physics Building, and the graduate students have 24 hour access to the journal
collection. The Physics Library subscribes
to 110 journal titles and has over 6500
monographs. A science librarian is available in the main library for bibliographic
instruction and assistance with information retrieval, such as on-line literature
search and access to full-text journals.
The user shop provides an opportunity for the
graduate students to fabricate their own apparatus, or to simply take care of minor machine work
on their own.
The Department maintains a fully
equipped machine shop which is staffed
by a professional machinist. The machinist fabricates equipment designed by the
faculty and graduate students, and trains
the students in mechanical design and
the use of machine tools.
Back Cover: Professor Paul Thibado with graduate
student Dan Bullock and undergraduate student
Ryan Wolf in the Molecular Beam Epitaxy
Laboratory.
The Department maintains a computer room exclusively for the use of physics graduate students. A wide range
of software is available on these computers.