Fall 2003
December 8, 2003 -- Lecture -- 7:30 p.m. -- Steward Observatory Lecture
Hall
Dr. Donald C. Backer, Professor of Astronomy and Research Astronomer,
Radio Astronomy Laboratory at the University of California at Berkeley
will present the thirty-eighth annual Karl G. Jansky
Lectureship. Backer's lecture, sponsored by Associated Universities, Inc.
(AUI) and the National Radio Astronomy Observatory (NRAO). The title
is Massive Black Holes, Gravitational Waves, and Pulsars. Backer is
being honored for his seminal contributions to the discovery of
millisecond pulsars. The Jansky Lectureship is awarded each year by the
Trustees of Associated Universities, Inc., to recognize outstanding
contributions to the advancement of astronomy. The lectureship is named
after Karl G. Jansky, an AT&T Bell Labs engineer who in 1932 first
discovered natural radio waves emanating from space. Backer's interests
include a variety of compact and energetic objects in the Milky Way and
beyond. Among these are pulsars, the nucleus of the Milky Way galaxy, and
the nuclei of other galaxies and quasars. His research employs large radio
telescopes and emphasizes the technique of high-resolution radio
interferometry. His work on millisecond pulsars is focused on the
consequences of the discovery in 1982 of a pulsar spinning at 642 Hz,
which is near the centrifugal limit for neutron stars. Backer and his
colleagues continue to monitor this pulsar and to search for other
millisecond-period pulsars. The timing measurements of these pulsars have
an accuracy that rivals the best atomic time standards on Earth. These
measurements also help astronomers to place stringent limits on the
magnitude of the background of gravitational radiation left over from the
Big Bang. Backer also oversaw the development of the
Berkeley-Caltech Pulsar Machine, which has been used on the National
Science Foundation's Robert C. Byrd Green Bank Telescope in West Virginia
to detect new pulsars in globular cluster M62, as well as the youngest
radio pulsar ever detected in supernova remnant 3C58. Backer will
deliver the Jansky Lecture in the Steward Observatory Lecture Hall,
University of Arizona, at Cherry Avenue between Second Street and the UA
Mall. The lecture is free and open to the public. Contact
Information: Jennifer Neighbours, NOAO. 520-882-8250,
extention 115. mailto:jneighbo@tuc.nrao.edu.
December 4, 2003 -- OSC Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Peter Smith of the University of Arizona Lunar and Planetary
Laboratory will present NASA’s Mars Exploration Program: The Next Five
Years. Abstract: The next five years continues a renaissance period
in Mars science. Next year begins with the landing of the first Mars
Exploration Rover (MER) on January 3 inside of Gusev Crater. The crater
was chosen because the geologic features resemble an ancient lake bed.
The MER science instruments were selected to analyze the history of the
site as written into the rocks. Unlike previous missions where images
were returned at a distance, the MER can approach a rock, abrade the
surface layers with a grinder to produce a flat clean surface, then image
this surface with a microscope. Other instruments can also determine the
elemental composition and iron chemistry of the rock. The mission becomes
a treasure hunt within a field of rocks looking for ancient signatures of
a wetter, warmer Mars that may have even supported life. Several weeks
later, a second MER lands at Meridiani, a feature the size of Texas that
emits strong hematite bands in the thermal IR as identified by the Mars
Global Surveyor orbiter. In 2005, the Mars Reconnaissance Orbiter will be
launched carrying among other instruments a 0.5-meter telescope that will
examine the surface with 30 cm/pixel resolution. The data returned by
this unprecedented remote sensing telescope, named HiRISE, is expected to
exceed 25 terabits. Off-nadir views of the same site allows for
stereoscopic imaging with height determinations of about 0.5 m; this
permits a lander-style view of the surface at hundreds of sites on Mars.
However, remote sensing is a poor substitute for landing on the surface.
The Phoenix mission recently awarded to the UA will land on the northern
plains in June 2008 and dig to the ice layers discovered by the Odyssey
orbiter. This unexplored region of Mars has the potential of revealing
the history of the ice as written into the soil minerals and could be a
habitat for potential Martian biology. Calendar info: Jose Sasian,
621-3733, is the Colloquium host. Refreshments will be served in the
Meinel Building lobby at 3:30 and the Colloquium begins at 3:45. This is
the last Colloquium of the semester. The Colloquium series will resume in
January.
November 25, 2003 -- Special Double Colloquium -- 2:00 p.m. -- Meinel 701
Dr. Fassil Ghebremichael, Associate Professor, U.S. Air Force Academy,
will present Beam Cleanup and Image Restoration Using a Photorefractive
Polymeric Composite. Abstract: We demonstrate the ability
to clean a phase-distorted laser beam and the reconstruction of badly
distorted image using a photorefractive polymeric composite. Additionally,
the applicable characteristics of the composite material were quantified.
Using four-wave-mixing and holographic techniques, we were able to obtain
an internal diffraction efficiency of ~80% at 80 V/µm and a
two-beam-coupling gain coefficient of 67 cm-1 at the same electric field
under our experimental conditions. Dr. Lewis DeSandre, Optical
Physicist, Air Force Research Laboratory, will present Multiband Agile
Neo-sensor (MANS). Abstract: A 3-meter diameter extreme
(~1 kilogram/square meter) lightweight optic is proposed as a satellite
imager on a high altitude airship. Hosts: Nasser Peyghambarian and
Buddy Martin.
November 20, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Raymond Kostuk of the University of Arizona Department of Electrical
and Computer Engineering and the Optical Sciences Center will present Some Interesting Aspects of Holography. Abstract:
Holography has long been an interesting part of optics due to its unusual
3-D imaging characteristics. However imagery is only one of the
interesting attributes of holography. In this presentation some of the
methods used to model, design, and fabricate a variety of optical
components using holographic techniques are described. The properties of
new holographic polymers are described that are providing a range of
applications to be realized in information processing and optical
communications. The possibility of using low-coherence digital holography
for medical imaging applications is also discussed. Colloquium host:
Jose Sasian, 621-3733.
November 13, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Daniel Vukobratovich of Raytheon Systems Company will present
The
Search for Unobtainium. Abstract: An old engineering adage states:
the best material for the job is not available – hence unobtanium
for the ideal material. Selecting the right material for advanced
reflective optical systems requires balancing performance and cost.
Indices of performance are used to select materials. For mirrors these
indices represent the ability of the material to resist deformation due to
inertial, thermal and temporal effects. Beryllium is the wonder metal,
with outstanding performance indices. Unfortunately some aspects of
beryllium such as its cost, place it in the category of unobtanium.
The search is on for materials that can replace beryllium. Candidates
include metal matrix composites, aluminum/beryllium alloys, silicon,
silicon carbide, and graphite composites. These new materials are not
completely developed; so what will be the new unobtanium?
Colloquium host: Jose Sasian, 621-3733.
November 13, 2003 -- AME Seminar -- 4:00 p.m. -- AME Building, Lecture
Hall, S212
Dr. Donald M. McEligot of The University of Arizona and the Idaho
National Engineering and Environmental Laboratory (INEEL) will present
Recent Studies with the World’s Largest Matched-Index-of-Refraction (MIR)
Flow System. Abstract: Recently INEEL has developed the
World's largest MIR flow system [Stoots et al., Exp. Fluids, 2001]. The
benefit of the MIR technique is that it permits optical measurements to
determine flow characteristics in passages and around objects to be
obtained without locating a disturbing transducer in the flow field and
without distortion of the optical paths. With a transparent model of
different refractive index than the working fluid, the optical rays can be
refracted in such a manner that measurements are either impossible (e.g.,
cannot "see" the desired location) or require extensive, difficult
calibrations. Thompson, Bouchery and Lowney [1995] demonstrated this
situation conceptually when laser Doppler velocimetry is applied to a rod
bundle; with refractive-index-matching the measurement and determination
are relatively straight forward while without matching the beams may not
cross to form the measurement control volume at the desired focal length,
if they cross at all. With hot-wire and hot-film X- or slant-probes to
deduce Reynolds shear stresses, the sensor volume required has a dimension
of the order of a millimeter perpendicular to the surface plus the
additional space necessary for the support prongs. With laser Doppler
velocimetry (LDV), an effective sensor diameter of about 60 micrometers or
less can be achieved so measurements can be made to y about 30 micrometers
before "intersecting" the surface. However, the wall can interfere with
the laser beams of an LDV system, especially when two- and three-component
measurements are employed. One way to eliminate these problems is to use
a fluid possessing a refractive index that is matched to that of the wall
material (MIR). The MIR technique is not new itself; e.g., Corino and
Brodkey [JFM, 1969] employed it to measure turbulence structure in a
circular tube earlier. The innovation of the INEEL MIR system is
its large size relative to previous experiments. The versatile INEEL
facility has been used for fundamental and applied measurements in a
variety of recent research projects: Transition in boundary layers
with the Lehrstuhl für Strömungsmechanik of Uni. Erlangen, Germany [Becker
et al., JFE 2002]. Flow phenomena in spent nuclear fuel canisters [McCreery
et al., IHTC 2002]. Flow fields around buildings for assessment of
computer simulations of fate and transport of airborne particulates
[Knight et al., ASME WAM 2002]. Effects of realistic surface
roughness on turbomachinery flows with U. Idaho [Budwig et al., APS DFD
2001, ASME WAM 2003]. Complex flows relating to advanced gas-cooled
nuclear reactors [McCreery et al., NuReTH-10, 2002]. Additional
studies now beginning include examination of complex flows relating to
supercritical water reactors, synthetic jet actuators with U. Wyoming and
flow through fractured porous media. The seminar will discuss the
technique, the facility and some examples of the projects accomplished and
in progress.
November 6, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Steve Kendrick and Paul Manhart of Ball Aerospace in Boulder, Colorado
will present An Overview of BATC's Role on the James Webb Space
Telescope (JWST) Project. Abstract: Ball Aerospace is
under contract to produce the optics for the largest space-based telescope
in history -- one that will operate a million miles from earth well beyond
the moon at a place called "L-2". It will also have to be folded up like a
big piece of origami to fit inside the rocket that will take it to L2. And
once there, the telescope will have to unfurl itself and then autonomously
assemble all of its parts to create one of the largest telescopes in
existence (6.6 meters in diameter, about 20 feet). The JWST primary mirror
will consist of an array of 18 hexagon-shaped, beryllium mirrors that have
been lightweighted to 10% of their original mass. Utilizing a wavefront
sensing and control system, these individual mirror components will be
phased to one another and individually adjusted in radius of curvature to
achieve the desired primary mirror performance. Once up and running, the
JWST will be one of the largest man-made telescopes around, and certainly
the largest one in space. It will radiatively cool itself on average to
about 40K and will support infrared detectors perhaps as cold as 6K, more
than minus 440 Fahrenheit. But once all this is done, the JWST will be the
world's best time machine and will be studying the first distinct
"objects" ever formed and the environment that created them.
Colloquium host: Jose Sasian, 621-3733.
October 31, 2003 -- Special Colloquium -- 11:30 a.m. -- Meinel 701
Mr. Kyozo Kanamoto of the Femtosecond Technology Research Association,
Tsukuba, Japan, will present Optical characterization of the nonlinear
properties of quantum and photonic-crystal structures for all optical
switches. Mr. Kanamoto will first discuss his company’s research
activities in the development of a Mach-Zender type all optical switch
utilizing InAs Quantum dots as nonlinear material and photonic crystals as
wave guides for the realization of all optical switches. He will then
discuss time-resolved optical nonlinearity measurement by a two color
pump-probe ellipsometry in InAs quantum dot waveguide. In this research,
optical nonlinear phase shift of larger that 90 degrees was obtained by a
pumping of 30pJ/um2. Delay time dependence of the phase shifts will also
be discussed. Another topic of discussion will be on sharp defect modes
and their response to ultrashort pulses in single photonic-crystal defects
based on air-bridge structure. In this research, sharp defect modes were
obtained with quality factors higher than 600 and observed the shift in
the defect modes for ultrashort optical pulses by utilizing two-photon
absorption. Nasser Peyghambarian, 621-4649, is the Colloquium host.
October 30, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Kazuhiko Oka, Visiting Research Scholar at the University of Arizona,
will present Snapshot, Simple, and Compact Methods for Spectroscopic and
Imaging Polarimetry. Abstract: The importance of the polarimetry is
rapidly increasing in many fields, such as optoelectronics, optical
communications, remote sensing, and biomedical optics. Some of these
applications impose new requirements that cannot be fulfilled by the
conventional polarimetry using mechanically-rotating elements. This talk
will present two recently-developed non-mechanical methods for the
analysis of polarization; one is the channeled spectropolarimetry and the
other is the imaging polarimetry with the birefringent wedge prisms. In
the channeled spectropolarimetry, two multi-order birefringent retarders
and an analyzer are used as a polarization analyzing optics. A
spectrometer followed by the analyzer offers a multiply-modulated
channeled spectrum, from which the wavelength-dependent Stokes parameters
are determined. In the imaging polarimeter with birefringent prisms, the
above idea is extended and applied to the measurement for the
spatially-distributed Stokes parameters. Both methods use no mechanical
or active elements for polarization modulation, and all the parameters
associated with the spectrally- or spatially-resolved state of
polarization of light can be determined at once. The principles of both
methods as well as some recent experiments will be described.
Refreshments will be served in the Meinel Building Lobby at 3:30 and the
Colloquium begins at 3:45 in Meinel 410. Eustace Dereniak, 621-1019, is
the Colloquium host.
October 23, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Dave Redding, NASA, will present Wavefront Control for Space
Telescopes. Abstract: By segmenting and folding the primary
mirror, very large telescopes can be packed into the nose cones of
rockets. An excellent example of this is NASA's James Webb Space
Telescope, a 6.5 m aperture cryogenic observatory scheduled for launch
after 2010. Once on orbit, the primary and secondary mirrors will be
unfolded and deployed into very nearly the right configuration, and the
shutter opened for first-light observations. These first-light
images are expected to be of very poor quality. Left uncompensated,
deployment errors, unanticipated thermal deformations, strain relief and
slippage induced by launch shock loading, fabrication errors and other
effects would severely limit imaging performance. This talk will
present automatic sensing and control methods for capturing, aligning,
phasing, and deforming the optics of such a telescope, going from initial
mm-level wavefront errors to diffraction-limited observatory operations.
These methods were developed for the James Webb Space Telescope and other
missions, and they have been demonstrated on several testbeds and
operational telescopes, including the Keck 2 Telescope. Included in
the discussion will be extreme-accuracy image-based wavefront sensing,
remote phasing of segmented telescopes, error modeling methods, and a
brief overview of upcoming space telescope missions. Refreshments
will be served in the Meinel Building Lobby at 3:30 p.m. For more
information, please contact: Jose Sasian, 621-3733, is the Colloquium
host.
October 16, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Raymond J. Hawkins of Mulsanne Capital Management will present Fisher
Information And Equilibrium Distributions In Econophysics. Abstract:
Abstract: We present a novel application of constrained Fisher
information: the reconstruction of probability densities implicit in
financial security prices. We illustrate this method by calculating the
densities implicit in bond and option prices and find the resulting
densities to be in accord with commonly held priors concerning density
smoothness. We also show that the Cramer-Rao bound can be used to
generalize the concept of asset-price volatility. Refreshments will
be served in the Meinel Building
Lobby at 3:30 p.m. Roy Frieden, 621-4904, is the Colloquium
host.
October 10, 2003 -- Opti 310 Guest Lecture -- 10:00 a.m. -- Meinel 410
Professor Yuri Kivshar of the Australian National University will present
Spatial Optical Solitons. Abstract: This talk will give an
introduction into the physics and properties of spatial optical solitons,
self-trapped optical beams propagating in self-focusing and defocusing
nonlinear media. We will present different examples of spatial solitons
including scalar, vector, bright, gap, vortex, and composite spatial
solitons, as well as discuss the basic features of the soliton interaction
and the formation of soliton clusters. For more information, please
contact Professor Grover Swartzlander 626-3723.
October 10, 2003 -- Three Special Colloquia -- 2:00 p.m. -- Meinel 564
Ms. Eriko Watanabe, Graduate Student, Second Year Doctoral Student, will
present Fabrication and Evaluation of Ultra-fast Facial Recognition
System. Abstract: We fabricate a fast facial recognition
system based on a VanderLugt Correlator combined with pre- and
post-processing developed by the author's group. With binarized CGH for
matched filter, correlation signals ascertain excellent performance of
this system. We implement 1000 faces/s throughput of 1-channel processing
and obtained the FNMR :4.6% and FMR :3.6%.
Ms. Yumi Okazaki, Graduate Student, First Year Master Course, will present
Optical Multiplex Holographic Storage Using Multimode Optical Fiber
Bundle. Abstract: We present a simple method for hologram
multiplexing in which a fiber bundle is employed as a device for producing
random reference patterns with a rotary movement. We write 70 images in a
LiNbO3 crystal and selectively read them out. We also investigate the
quality of readout images.
Ms. Hiroko Nagano (seiner) will present Novel Application of Arrayed
Waveguide Grating to Compact Planar Spectroscopic Sensors.
Abstract: An arrayed-waveguide grating(AWG) is attractive not only
for use in optical wavelength-division-multiplexed networks but also for
the potential application to various spectroscopic measurements. We
propose here a compact planar spectroscopic sensor based on the AWG.
Liquid sample under test is poured into a groove in the first slab region
of AWG. The detector that is placed at the end-face of the second slab
region measures spectral transmittance of the liquid. Fundamental device
characteristics and preliminary experimental results are reported.
Tom Milster, 621-8280, is the host.
October
9, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Philip Russell of the Optoelectronics Group, Department of Physics,
University of Bath will present Spinning Webs for Catching Light.
Abstract: Photonic crystal fibers (PCFs) have been the focus of
increasing interest since the first working example was reported in 1996.
Although superficially similar to a conventional optical fiber, PCF has a
unique microstructure, consisting of a "web" of microscopic holes (or
channels) that run along its entire length. These holes act as
optical scatterers, which suitably arranged can trap light within a
central core (either hollow or made of solid glass). The holes can
range in diameter from ~25 nm to ~50 μm. Although
most PCFs are formed from pure silica glass, they have also recently been
made using polymers and non-silica glasses, where it is difficult to find
compatible core and cladding materials suitable for conventional total
internal reflection guidance. Light can be controlled and
transformed in these fibers with unprecedented freedom, and many new
applications are emerging. For example, an ultra-small core fiber
made from silica glass and surrounded by very large air-holes can be
arranged to have a zero chromatic dispersion wavelength in the 800 nm
Ti:sapphire band. This fiber produces spectacular spectral
broadening of high repetition rate 100 fsec pulses, with a brightness some
10,000x brighter than the sun and a similar bandwidth. This source
is transforming the fields of optical coherence tomography, spectroscopy
and frequency metrology. In its hollow core form, PCF allows light
to interact -- strongly, reproducibly and over long path-lengths -- with
low-density materials such as gases, vapours and liquids. This
development has major implications for gas-based nonlinear optical and
laser devices. Recently a hydrogen Raman cell was demonstrated with
a threshold energy of 800 nJ -- some 100x lower than previously reported.
These are just two examples of how the PCF concept is ushering in a new
and more versatile era of fiber optics, with applications spanning many
areas of science and technology. Refreshments will be served
in the Meinel Building
Lobby at 3:30 p.m. Jerome Moloney, 621-6755, is the Colloquium
host.
October 2, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Professor Eli Yablonovitch of the
Electrical Engineering Department, University of California, Los Angeles,
will present The World of the Very Small; Nano-lithography, Nano-electronics
and Nano-photonics. Abstract: Photonic crystals, the electromagnetic
analog of semiconductor crystals, have stirred the imagination toward
photonic integrated circuits. Integration at the tiniest scale of
photonic crystals allows the largest number of components to be produced
from a single wafer, reducing cost, and allowing considerable optical
complexity. There have been a series of practical difficulties standing
in the way of building practical micro-photonic circuits that are
gradually being solved; including, the input/output coupling efficiency
problem, the nano-fabrication accuracy problem, the active device issues,
electrical modulation schemes, device design software and simulation.
Some of these problems are already solved, and we can project solutions to
the others over the next few years. Refreshments will be served in the
Meinel Building Lobby at 3:30 p.m and the Colloquium begins at 3:45 p.m.
in Meinel 410. For more information, please contact the Colloquium host:
Professor Hyatt Gibbs at 621-4941.
September 25, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Professor Stephan Koch of the Physics Department, University of Marburg,
will present Excitons In Semiconductors: An Old Subject In New Light.
Abstract: Starting from known facts about atoms, solids and their
optical excitations, this talk summarizes well established, but
nevertheless partially controversial aspects of electron-hole excitations
in semiconductors. We discuss semiconductor absorption and coherent
excitons, as well as semiconductor luminescence and incoherent excitons.
It is shown, that "new light", i.e. terahertz spectroscopy makes it
possible to unambiguously identify excitonic populations, and - more
generally - correlated states in semiconductors. Intriguing aspects of
photonic crystal semiconductor structures and their influence on excitonic
excitations are outlined. It is shown that well localized excitonic
wavepackets can be coherently generated with the possibility of observing
coherent expansion dynamics, interaction induced exciton localization, and
even superradiant emission. Refreshments will be served in the
Meinel Building Lobby at 3:30 p.m. Galina Khitrova, 621-4940, is the
Colloquium host.
September 18, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Professor Emeritus Stephen Jacobs of the University of Arizona Optical
Sciences Center will present The
Amazing Fabry-Perot Interferometer; Understanding It And Its Place In
The World Today. Abstract: The Fabry-Perot resonator (FPR)
is a beautiful and versatile device whose uses far exceed its function
as a spectroscopic tool or as a resonator for a laser oscillator.
No optical engineer or scientist can afford not to understand this
remarkable device. In the course of many years of teaching I have
collected a number of intriguing ways of looking at the FPR. Some of
these are as simple as back-of-the-envelope estimates. Others are
snatches of wisdom gleaned at coffee breaks. Still others are an
appreciation of the unanticipated role of diffraction in the race to
make the first laser. I will include some puzzlers I have thrown
at students after they feel they understand the FPR. (PRELIMS)
Finally I will discuss some less well known applications of the FPR,
such as detection of trace pollutants (Ring-down time), increased
sensitivity for gravity wave detection (LIGO), pulse-shaping (time
domain properties), laser-heterodyne measurement of DL
or Df,
and
cavity QED.
Refreshments will be served in the Meinel Building Lobby at 3:30 p.m.
Jose Sasian, 621-3733, is the Colloquium host.
September 15, 2003 -- Special Seminar -- 1:30 p.m. -- Meinel 701
Professor Dr. Peter Meissner of Technische Universitat Darmstadt,
Germany will present Micro-Mechanic Tunable Optical Filters, Receivers,
and VCSELs. Abstract: We
report on the fabrication and the characterization of bulk
micro-mechanic tunable optical filters, receivers, and VCSELs. All these
devices use a half symmetric Fabry-Perot resonator with a concave
mirror. Thermal as well as electrostatic actuation principles are used.
The filters were already tested in a WDM environment. For the VCSELs we
present a new two chip approach. The VCSEL is composed of two chips: one
mirror membrane chip with a movable curved mirror that can be displaced
by electro-thermal actuation to adjust the cavity length and one 'half
VCSEL" chip consisting of a fixed bottom mirror and an amplifying active
region. The possibility of separate optimization of both chips and a
long cavity are the main advantages of this approach, which is
appropriate for photo pumping as well as for an electrical pumping
scheme. The feasibility of this approach is proved by the measurement
results of an optically pumped VCSEL with more than 0.5 mW continuous
wave single mode output power at room temperature over a tuning range of
24 nm. For more information, please contact
Professor Franko Kueppers at 626-1778.
September 12, 2003 -- Special Seminar -- 1:30 p.m. -- Meinel 701
Professor Werner Weiershausen of Deutsche Telekom T-Systems Technology
Center, Darmstadt, Germany will present Polarization Mode Dispersion,
Theoretical Modeling Approaches and Practical Consequences for Optical
Fiber Transmission. Abstract: Polarization-Mode
Dispersion (PMD) has been under investigation since mid of the 1980's,
strongly gaining importance in the last years in order to enable
cost-effective fiber-optical WDM systems with ultra long-haul or
high-speed signal transmission. Still the problem 'PMD' is not
completely solved and signal-pulse distortion effects to first and
higher orders still have to be studied. The talk will focus on a
theoretical representation of first-order PMD which in the future may
also serve for further principal investigation of higher-order PMD
behavior. In order to give a more complete overview the presentation
will further discuss experimental results from lab and field trials
within Deutsche Telekom's fiber network. For more information, please
contact Professor Franko Kueppers at 626-1778.
September 11, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Lloyd W. Hillman, Chair of the Physics Department at the
University of Alabama-Huntsville, will present The Eye
OximeterProject-Viewing the Body through the Eye. Abstract:
The eye is a unique organ. The retina is the only place on the body
where we can observe arteries and veins directly without thick
intervening layers of skin or tissues. Furthermore, the retinal
vasculature is a potential source of perfusion data. The Eye Oximeter (EOX)
exploits this. The EOX scans low powered laser light at several
wavelengths into the eye and across the large vessels of the retina
around the optics nerve head. The reflected and scattered light is
collected and analyzed. This technique yields measurements of oxygen
saturation, vessel diameter, and blood hematocrit. This in-the-body
spectroscopic measurement is fast and noninvasive. In this talk, I will
overview the EOX program. There are two main thrusts to the EOX program.
The first is the basic scientific and bioengineering issues of the
retinal scanning technique used in the EOX. This includes research in
biophysics, optics, electronics, signal processing and analysis,
software development, engineering, and system integration. Second there
are the medical applications and clinical goals. Key to the success of
this bio-medical engineering program has been the synergistic teaming
between the technology-based researchers at UAH and medical researchers
at the University of Alabama at Birmingham (UAB) Medical School.
Together, we have shown that the EOX gives a sensitive measurement of
blood loss and can determine internal bleeding and the effectiveness of
trauma intervention. The health cost benefits are numerous. Since the
measurement is fast, noninvasive, and presents minimal risk to the
patient, a broad population will benefit by receiving critical
diagnostic measurements that presently are invasive, high-risk and
expensive. Refreshments will be served in the Meinel Building
Lobby at 3:30 p.m. Russell Chipman, 626-9435, is the Colloquium
host.
September 4, 2003 -- Colloquium -- 3:45 p.m. -- Meinel 410
OSC
alumnus Mitchell Ruda of Ruda & Associates, Inc. and Cardinal Optics,
Inc. will discuss Near-Death and Hysterical Experiences in Optical
Alignment. Abstract: Aligning
optical systems frequently occurs against the backdrop of a project that
is behind schedule and seriously over budget. Consequently, this places
the unlucky individuals responsible for this task under undo stress.
Equally frustrating is the fact that they are often the first people to
discover that parts don't fit, optics are made wrong and the alignment
plan was poorly thought out. This tongue-in-cheek presentation
will review a handful of very useful and basic alignment methods and the
sometimes memorable moments when they are used under pressure, not used
correctly or not used at all.
Refreshments will be served in the Meinel Building Lobby at 3:30 p.m.
Jose Sasian, 621-3733, is the Colloquium host. |