Colloquium

April 21, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Wayne H. Knox, Professor of Optics and Director of the Institute of Optics at the University of Rochester, will present Dispersion Micromanagement in Holey Fibers.  Abstract:  We discuss recent experiments in which the dispersion of a holey fiber is managed at the sub-millimeter scale. We find that the femtosecond continuum generation process is strongly modified in a fiber with rapidly changing dispersion.

April 14, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Shahab Etemad, Chief Scientist and Director at Telcordia Technologies, will present Recent Developments in Optical-CDMA.  Abstract:  The success and widespread use of CDMA in the wireless domain has renewed interest in exploring its use in the optical domain, which, however, presents a different set of challenges and rewards. A broadband network based on Optical-CDMA has the advantage of using codes like telephone numbers, as opposed to wavelength in a WDM network, to determine connectivity and address network OAMP. Whereas WDM networks have been around for more than a decade, it is now that some laboratory results are showing Optical-CDMA is not just a myth. In this talk we review recent progress in Optical-CDMA and its feasibility for telecom and datacom applications. In particular we shall highlight Telcordia's vision and progress in addressing such problems as low spectral efficiency, multi-user interference and exposure to network impairments.

April 7, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Kelly S. Potter, OSC alumnus and University of Arizona Associate Professor of Electrical and Computer Engineering and of Optical Sciences will present Defects to Devices:  Engineered Photoresponse of Optical Materials.  Abstract:  Photoinduced changes in physical, electronic, and optical properties provide a powerful opportunity to manipulate the behavior of a broad variety of materials in a non-contact manner.  In the case of a photoinduced refractive index change, the precise photosensitive response is dependent upon defects present in the materials which are formed as a result of such parameters as the material composition and structure and the optical and environmental conditions employed during photo-processing of the material.  Manipulation of such issues, thus, plays a crucial role in the development of tailored materials with targeted performance characteristics.   A summary of our efforts to identify and characterize photosensitive materials systems, to provide options for write-once, read-many and “write-as-needed” refractive index structures, will be offered to illustrate these concepts.

March 31, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Professor Jacob B. Khurgin of the Department of Electrical and Computer Engineering Johns Hopkins University will present Linear and Nonlinear Optical Devices Based on Slow Light Propagation: Figures of Merit.  Abstract:  Various linear and nonlinear phenomena associated with modifying group velocity of electro-magnetic waves and commonly referred as a “slow light” have generated substantial interest in the community of optics, but there still exists a number of unanswered questions regarding the degree by which “slow light” can enhance the performance of various optical systems. The purpose of this talk is to clarify at least some of the most important issues related to  “slow light”.  After a brief survey of the existing and proposed “slow light” schemes such as photonic crystals, coupled resonator lines, electro-magnetically induced transparency, and other coherent storage schemes, we outline their similarities and differences. Then we derive simple analytical expressions for the performance limitations of optical delay lines and various nonlinear devices due to higher order dispersion and residual loss and show that higher order dispersion severely limits the bandwidth of the slow light devices.  Then we propose and analyze novel of ideas for increasing the bandwidth without sacrificing performance. These methods range from straightforward dispersion-compensation schemes to the most elaborate methods using adiabatic changes and various parametric processes. These methods are shown to mitigate, (with various degrees of success) the inherent impairments of slow light schemes.  The conclusion is that while the slow light is definitely not a perfect solution, there still exists a practical application niche for it.

March 24, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Alan D. Marmorstein of the University of Arizona Department of Ophthalmology and Optical Sciences Center will present Fundus Fluorescence Ratiometry: A Tool for Early Diagnosis of Age-Related Macular Degeneration?  Abstract:  Age-related macular degeneration is the leading cause of incurable blindness in the United States causing significant vision loss in >1.7 million Americans and affecting vision in as many as 13 million.  Diagnosis of AMD is typically accomplished only after vision is lost.  Preventative therapies are difficult to consider and clinical trials of medications intended to prevent AMD or reverse early effects are nearly impossible due to a lack of early diagnostic tools.  The retinal pigment epithelium is the major cell type present at site where AMD pathology develops.  These cells exhibit autofluorescence as a product of age.  The autofluorescence is due to accumulation of lipofuscin.  We have recently shown that deposits in the extracellular matrix that supports the RPE cell also exhibit autofluorescence, though with different emission properties.  As a result we have proposed that analysis of these spectra using ratiometric imaging techniques could provide a means for early diagnosis of AMD.  Currently our laboratory is building prototype devices for fundus fluorescence ratiometry and using these prototypes to test the correlation between "ratiometric maps" of the ocular fundus and AMD pathology.

March 22, 2005 -- Special Presentation -- 2:00 p.m. -- Meinel 701
Dr. Pavel Polynkin, Optical Sciences Assistant Research Professor and Candidate for Photonics Faculty Position, will present Development of Novel High-Power Fiber Laser Sources: Challenges and Opportunities.  Abstract:  The field of infrared fiber lasers undergoes a revolutionary development nowadays. Kilowatt-level multimode fiber sources have been recently demonstrated and commercialized. This progress however has not been as rapid with single-frequency and short-pulse fiber lasers, where crossing into the Watts-level output powers imposes unique challenges. I will describe the constraints and trade-offs to be considered in designing such lasers. Several recently developed techniques that allow for realization of the laser designs common in bulk-optics, in the all-fiber format will be presented. These developments have lead to a demonstration of both single-frequency and short-pulse fiber lasers with output power in the Watts range.

March 10, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Mark Neifeld of the Department of Electrical and Computer Engineering and the Optical Sciences Center at the University of Arizona will present Some Information-Based Optical System Studies.  Abstract:  Information theory (IT) is more than 50 years old and has had a significant impact on nearly every modern approach to computation, communication, and storage. This talk will identify a few key features of IT that are particularly relevant to the design and/or analysis of optical systems. I will discuss optical systems for data transmission as well as those for imaging. Examples of our application of IT to the former include (a) the analysis of information propagation in fast- and slow-light media and (b) the design of nonlinear error correction codes for fiber-optic channels. Examples of the application of IT to imaging include (a) the design of non-traditional 2D and 3D imaging systems, (b) identification of a new super-resolution algorithm for laser radar, and (c) the exploitation of channel diversity in distributed imaging systems and its implications for the design of ultra-thin cameras.

March 3, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Wolfgang Stolz of the Material Sciences Center and Department of Physics at Philipps-University will present Unique Optoelectronic Applications of Dilute Nitride III/V-Compound Semiconductor Heterostructures.  Abstract:  In recent years the  novel class of dilute nitride III/V-semiconductors and corresponding heterostructures are gaining increasing interest both from fundamental as well as applied point of view. This is caused by their unique optoelectronic properties and in particular by the novel conduction band formation process leading to an extreme band gap bowing with increasing N-content in the crystal. This characteristic of the (GaIn)(NAs)/GaAs-model system allows for long wavelength emission devices based on GaAs-substrate. The achieved understanding of the fundamental properties with respect to solar cell as well as laser applications like vertical (external) cavity surface emitting lasers (V(E)CSEL) will be presented and discussed.  In addition, the completely new material system Ga(NAsP) on GaP- and, due to the similar lattice constant also on Si-substrate is introduced. The incorporation of N in the Ga(NAsP)/GaP-material systems allows for a significant reduction in the lattice constant, which leads to a dislocation free, epitaxial deposition of a direct band gap semiconductor material system on GaP-substrate. By applying a variety of physical investigation techniques the high crystalline quality as well as the direct band gap character of the novel Ga(NAsP)/GaP have been verified. First optical pumping experiments indicate  that even laser emission has been achieved already at this early stage of development. These very promising results might form the basis for a real monolithic integration of III/V-based optoelectronic and Si-microelectronic functionalities in the very near future.

March 3, 2005 -- Distinguished Speaker Seminar Series -- 2:00 p.m. -- Student Union Kiva
Sponsored by the Department of Electrical and Computer Engineering.  Reception with refreshments to follow the talk.  Kang G. Shin, Professor of Computer Science, EECS Department, The University of Michigan, will present Management and Application of Sensor Networks.  Abstract:  Under the auspices of DARPA, NSF, ONR and industry, we have been developing middleware for securely managing sensor networks for environment monitoring. This talk will begin with the generic aspects of sensor networks, and then describe details of our current research that covers adaptive query processing (AQP), minimum-cost routing, and security.  Sensor networks, built with thousands of small and smart sensor nodes, may be deployed for various applications, which usually require a certain pre-specified network lifetime. I will first describe a hierarchical architecture for query processing in such sensor networks, and then focus on energy-aware adaptive query processing. Especially, I will present (1) a cost-based query allocation algorithm that minimizes the total power consumption by maximizing cost sharing among different queries; and (2) an energy-aware Quality-of-Service (QoS) adaptation algorithm that gracefully makes tradeoff between total power consumption and total QoS of all queries when node availability or workload changes.  Among many others, efficient routing between sensor nodes and protection sensor nodes and information exchanged between them are essential to support applications like AQP.  Hence, the second part of my talk will deal with these two issues.

March 3, 2005 -- Special Presentation -- 12:30 p.m. -- Meinel 701
Paul L. Voss, Post-Doctoral Fellow at Northwestern University and Candidate for OSC Photonics Faculty Position, will present Recent Progress in Fiber Parametric Amplifiers: Experiment, Theory and Novel Applications.  Abstract:  Recent developments in the design of microstructure fiber and so-called highly nonlinear fiber have greatly extended the capabilities of the fiber parametric amplifier (FPA), a device which provides optical gain through nonlinear mixing of a pump wave with a signal and a generated idler wave. These improvements in fiber design have allowed for significant improvement in the gain slope and bandwidth of these amplifiers. FPAs can provide high power gain at wavelengths where no commercially available amplifier exists. In addition to providing optical gain, these amplifiers provide broadband ultra-fast all-optical wavelength conversion with gain.  Recent research has provided the first physically correct treatment of FPA noise. On the theoretical side, Dr. Voss has developed a quantum theory of fiber parametric amplification including distributed linear loss and noise-inducing Raman gain and loss.  This theory has allowed calculation of the noise properties of FPAs.  Dr. Voss has experimentally verified this theory using innovative detection techniques.  In addition to applications in optical communications, FPAs are of great interest in the burgeoning field of quantum communications. Because they can produce twin photons in optical fiber, eliminating inefficient and clumsy coupling from a nonlinear crystal into an optical fiber for transmission, they are a promising as a source for secure secret key distribution. Dr. Voss will review pioneering work at Northwestern that shows the suitability of this new photon source for quantum cryptography applications. In addition, the FPA quantum theory describes these experiments and has proved useful in optimizing these experiments. The future looks promising for this and other novel applications of FPAs.

February 24, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Dr. Duncan Moore, Rudolf and Hilda Kingslake Professor of Optical Engineering at the University of Rochester and former Associate Director for Technology in The White House Office of Science and Technology Policy, will present Gradient-Index Optics in Nature and the Manmade World.  An abstract is not available.

February 17, 2005 -- Optical Sciences Double Colloquium -- 3:45 p.m. -- Meinel 410
(1)  Michael Edelman, a partner in the intellectual property litigation group of Dechert LLP, will present Overview of IP -- The Legal Perspective.  Abstract:  Michael Edelman's presentation will provide an overview of legal issues relating to intellectual property rights, including patent, copyright, trademark, and trade dress rights.  He will address issues relating to the obtaining of intellectual property rights, and the manner in which parties can enforce such rights in the Patent and Trademark Office or the courts.  he will first discuss the different types of intellectual property rights that exist (such as patent, copyright, and trademark rights).  He will address the manner in which intellectual property rights can be obtained in the Patent and Trademark Office, including an overview of how a patent is typically applied for and prosecuted.  Then he will address the different strategies for enforcement of those rights, both in the Patent and Trademark Office and the courts.  He will then particularly focus on issues relating to patent litigation, including the meaning of infringement and validity in patent litigation and the manner in which courts “interpret” the meaning of patent claims.  Lastly, he will discuss recent case law on important intellectual property issues, and address how this case law will effect the future enforcement of patent and other intellectual property rights.  He will address how these cases represent the continuing struggle of federal courts to balance intellectual property rights with more pragmatic concerns of litigants or potential litigants, and what these cases may mean for parties that may become involved in an intellectual property dispute.
(2)  Dr. Richard G. Zech will present The Role of the Technical Expert in Patent Litigation.  Abstract:  The United States has about 75% of the world's lawyers.  About 1 in 250 people in the US are lawyers (about the same ratio as Ph.D.s).  The number of litigations grows annually almost exponentially.  Much of this litigation explosion has to do with the growth of patent litigation in the US (Asia and Europe too).  Most court officers (the lawyers and judges) are not generally technology literate.  In patent litigation (and other litigations involving technology) a need exists for disinterested, technology-qualified individuals to explain and interpret the science and engineering.  This is a basic definition of the expert witness.  In the context of today's paper, he or she helps interpret the claims and specification of a patent and helps to determine its validity if working for the defense.  Expert witness work is challenging; something akin to defending your Ph.D. thesis before professors who consistently gave you C grades.  Only now, your interrogators are (fire-breathing) lawyers bent on discrediting you.  Initially, you'll find it an Alice-in-Wonderland experience.  Long-term, you may come to enjoy and respect the work.  My goal in this presentation is to share with you the experience and knowledge I've gained as an expert witness over the past nearly 15 years.  I will teach you the basics of behavior, ethics, and procedures and how the system works.  I will address the qualities that make you an expert witness candidate.  In a word, this is the Cliff Notes of expert witnessing.  Much of what you will need to know must eventually be learned on the job under a lawyer's direction.

February 10, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Dr Valorie Valencia, OSC PhD 1991 and co-founder of Authenti-Corp, will present Biometrics: The Good, the Bad, and the Ugly.  Abstract:  Biometric systems are rapidly being implemented around the world in a wide variety of applications. This presentation will introduce the field of biometrics, the automated recognition of individuals based on their behavioral and biological characteristics. Various types of biometric technologies and how they work will be presented. Examples of both eminent and novel biometric applications will be profiled and the benefits of biometric technologies highlighted (The Good). The challenges faced by the biometrics industry will also be presented, such as the lack of statistical models to predict operational performance of biometric systems and the much-publicized accounts of how biometric systems can be circumvented to compromise security (The Bad). Efforts underway to address performance and security shortcomings of biometric technologies will be described. “Big Brother” and personal privacy concerns surrounding biometric implementations will also be addressed (The Ugly). The presentation will conclude with a discussion of future trends and ripe areas for research in the field of biometrics.

February 3, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Professor Jerome V. Moloney of the Arizona Center for Mathematical Sciences and the Optical Sciences Center will present Computational photonics design tools for kW class semiconductor lasers, nanophotonics components and systems.  Abstract:  Physically and mathematically self-consistent modeling and large scale computer simulation are emerging as powerful design tools for current and future complex photonics systems. In the talk, I will motivate the need for such simulation approaches in the context of two seemingly disparate research areas – developing new classes of kW level high brightness semiconductor lasers and modeling micro- and nano-scale optical systems. An overriding theme of the talk will be the use of nanostructured materials to dramatically extend the dispersion landscape well beyond the rather limited intrinsic dispersion of materials. In designing a kW class optically-pumped vertical extended cavity laser, for example, the multiple quantum well (MQW), resonant periodic gain (RPG) structure can be exploited to greatly enhance the gain perpendicular to the VECSEL laser axis. Designing the RPG structure such that the lasing wavelength lies at the edge of its photonic stop-band slows down the light, thereby increasing the gain.  Thermal management proves critical to scaling such VECSEL chips from their present 40 Watt output levels to future kW-class high brightness performance.   The second part of my talk will focus on developing sophisticated computer algorithms to model the interaction of light with sub-wavelength nanoscale features. The rapidly emerging field of nanophotonics is spurring applications in on-chip nanocircuitry, optical data storage, sensing, cancer diagnostics, etc. Solving the time-domain Maxwell’s equations in 3D offers huge computational challenges especially when the problem at hand involves widely disparate space scales. I will describe a space and time mesh refinement scheme that promises to make the simulation of large 3D nanophotonics systems with present supercomputing systems feasible.   

January 27, 2005 -- Optical Sciences Colloquium -- 3:45 p.m. -- Meinel 410
Robert Eckardt, Senior Staff Scientist at Cleveland Crystals returns to the Optical Sciences Center to present Free-Space Laser Resonators.  Abstract:  Free-space propagation and optical resonators remain topics of fundamental importance in laser science.  The discussion of Gaussian beams is a convenient place to start a discussion of these topics.  Gaussian beams provide a good approximation to the spatial characteristics of the output of many lasers and a reference of beam quality through the parameter M-squared.  Propagation of a Gaussian beam is easily calculated with analytic expressions.  This is useful for such things as the design of simple laser resonators or matching the spatial distribution of a laser output to an application, a process sometimes called mode matching.  Laser resonators are classified as stable or unstable.  Both types are capable of generating stable optical beams of high quality.  The choice of resonator type depends on the particular application.  Gain-guided resonators with plane-parallel mirrors are common in laser-pumped laser systems.  Numerical techniques based on Fourier optics are useful for modeling the development of laser oscillations in plane-parallel and other unstable resonators.  And the Gaussian beams of stable resonators provide and convenient check of the numerical calculations.  Axial modes enter into consideration when the laser oscillation is allowed to expand beyond a single frequency.  Free-space laser resonators provide a foundation for understanding the more complex multiple-axial-mode laser oscillations.   Biography:  Robert Eckardt has worked in the areas of nonlinear optics and solid-state laser development for more than forty years.  Currently he is a Senior Staff Scientist at Cleveland Crystals where he works on the characterization of electro-optic and nonlinear-optical materials and performs modeling of nonlinear optical interactions.  He is also collaborating with researchers at Vilnius University in Lithuania on techniques of optical characterization.  He has held the positions of Research Professor at the Optical Sciences Center of the University of Arizona, Senior Research Associate at Stanford University, and Physicist and Research Physicist at the Naval Research Laboratory in Washington DC.  He received a Bachelor of Science degree in Engineering Physics from the University of Illinois, a Master of Science degree in Physics from the University of Maryland, and a Ph.D. in Applied Physics from Stanford University.   Robert Eckardt was coeditor of two special issues of the Journal of the Optical Society of America B on optical parametric devices published in November 1995 and September 1999, and he served as an Optics Letters topical editor for nonlinear optics from 1998 to 2004.