Optical Sciences Colloquium Series

Abstract: The physical limit for the number of pixels per color channel per frame in an optical imager is approximately equal to the aperture area in square microns. While this limit is essentially achieved in megapixel scale cell phone cameras, the limit of 100 megapixels for cm apertures, 10 gigapixels for 10 cm apertures and 1 terapixel for meter apertures is far beyond current practice. These pixel counts may be further increased by factors of 100-10,000 in spectral and 3-D imagers. At the physical limit, a practical imager may easily deliver >1 terapixel per second. Imagers that scale to the physical limit must overcome challenges in the design of lenses, electronic focal planes and image processing units. This talk reviews efforts to overcome these challenges through the DARPA AWARE program. We specifically discuss the construction of a compact 5 gigapixel camera and we discuss implications for such cameras in online and broadcast media. Presented Thursday, October 4, 2012.

Abstract: The fate of an ultrashort laser pulse propagating in air depends crucially upon its peak power. Below a critical value, Pcr, group velocity dispersion and beam diffraction combine to rapidly reduce the pulse intensity. On the other hand, if P is less than Pcr, a completely different behaviour is observed. In this case, instead of decreasing, the pulse intensity increases with distance up to the point where it becomes sufficiently high (~1013 W/cm²) to ionize air. The pulse then retains this high intensity for very long distances that can reach kilometers. This regime is called filamentation. In this lecture the basic notions at the heart of filamentation will be introduced. Techniques to characterize air filaments will be described. This includes measurements of the beam size, pulse intensity, pulse duration, density and length of the plasma column created in the wake of the pulse, and the plasma density evolution. These results are well reproduced by numerical simulations. Recent experiments will be described which allow to manipulate and to exchange energy between filaments. A second part will be devoted to applications of filaments. They include the triggering and guiding of low resistance, high current electric discharges, the creation of short bursts of terahertz radiation, the illumination of distant objects, the use of filaments as virtual RF antennas. Presented Thursday, October 11, 2012.

Abstract: Organic semiconductor materials offer the potential of low-cost and flexible displays and lighting solutions, some of which have already made it to the marketplace. Despite this, much of the underlying optical physics remains poorly understood and hinders progress towards better and more powerful devices. In this talk, the basic properties of organic semiconductors will be reviewed and some of the outstanding issues explored. We will show how simple models based on dipole-dipole coupling can be validated (by comparison with quantum chemistry) and used to compute optical properties such as absorption, gain and luminescence spectra. Recent theoretical and experimental results on the optical pulse propagation and timescales of excitation transfer and hopping in linear oligoflourine and star-shaped samples will be also presented. Presented Thursday, September 20, 2012.

Abstract: We often forget in our daily life that air does not have the same optical properties as vacuum. At least in New Mexico and Arizona, we are made aware that it has an index of refraction, and that it is not the ideal homogeneous optical material. However, in daily experiments, we do not think too often of air as being a nonlinear medium, having a complex intensity dependent index of refraction, nonlinear absorption, induced birefringence, and becoming a partially conductive medium. These properties lead to light filamentation, a situation where the nonlinear properties of air dominate the propagation properties. It has produced — and still is producing — a flurry of papers and dreams of wild applications. Aside from the practical or unpractical applications, it is a unique example of light-matter-light interaction, which makes us rethink basic concepts of electromagnetism, even down to the nature of an index of refraction. He investigating two types of filaments, produced either by femtosecond pulses in the near infrared (800 nm) and by nanoscond pulses in the ultraviolet (266 nm). The two are interesting in comparison because of their very different wavelength and temporal regime. An infrared filament is an ideal object of study for investigating strong field light-matter interaction, in which light and matter have a mutual recordable effect on each other. For a few hundred femtosecond-long infrared filament in air, the interaction of light is with bond electrons in atoms or molecules, with free electrons created by tunnel ionized, and with partially orientated molecules. Since the modification of light happens in a time scale much faster than a plasma period, a careful microscopic (in the fs scale) study of the parameters involved in filament formation is needed. In this talk, Diels shows how pre-filamentation propagation can cause a) new spectral development and b) polarization-dependent filamentation. We used an aerodynamic window to prepare the focus in vacuum before launching the filament in air. A model to study the index of refraction of tunneled electrons in the femtosecond time scale of a laser pulse was presented.

Abstract: Slow-servo diamond turning has revolutionized what is possible in optical fabrication. As a result, optical design provides new horizons where freeform surfaces may offer new degrees of freedom. In this talk I will provide a brief history of the emergence of freeform optics and point to a growing customer base. I will then discuss recent advances in surface shape descriptions for freeform optics from phi-polynomials to multicentric radial basis functions. Finally, I will show how freeform surfaces may provide in one case study a factor of 10 in field area. Insight into the correction of aberrations will be provided and a metrology approach to testing freeform surfaces will be discussed. Dr. Rolland is Brian J. Thompson Professor of Optical & Biomedical Engineering; Associate Director of the R.E. Hopkins Center for Optical Design & Engineering. Professor Rolland's central research interests are in the fields of optical instrumentation and system engineering. Research areas of interest are (1) Optical System Design for Imaging and Non-imaging Optics (2) Physics-based modeling, and (3) Image Quality Assessment. These areas have been applied to Eyewear Displays for Augmented Reality, Optical Coherence Imaging, Biomedical and Medical Modeling and Simulation, Alignment of Optical Systems, and 3D Velocimetry.

Abstract: The National Ignition Facility, sited at the Lawrence Livermore National Laboratory in Livermore, Calif., is a 192-beam, 1.8-MJ (351 nm) laser designed to compress ~250 µg spheres of deuterium and tritium to thermonuclear ignition. Fuel compression is achieved through an ablative rocket drive mechanism where the outer wall of the fuel shell is ablatively removed by a 300 eV radiation field. The 300 eV field is produced through laser matter interactions at the wall of either a gold or uranium hohlraum surrounding the capsule. Obtaining ignition will depend on controlling several critical aspects of the implosion, including the amount of kinetic energy transferred to the fuel, the internal energy generated within the fuel, the symmetry of the implosion, as well as maintaining the hydrodynamic stability of the fuel as it compresses. Imaging diagnostics provide unique insight into the performance of these implosions, and the NIF has assembled a broad suite of imaging capability, utilizing both X-rays and neutrons to diagnose critical aspects of the implosion process. In this presentation I will review the basic motivation for the inertial confinement fusion experiments taking place at the NIF, as well as a description of the NIF laser and its diagnostic capability, with an emphasis on imaging. This work was performed for the U.S. Department of Energy and National Nuclear Security Administration and by the National Ignition Campaign partners: Lawrence Livermore National Laboratory, University of Rochester Laboratory for Laser Energetics, General Atomics, Los Alamos National Laboratory and Sandia National Laboratories. Other contributors include Lawrence Berkeley National Laboratory; the Massachusetts Institute of Technology; Atomic Weapons Establishment, England; and Commissariat à l’Énergie Atomique, France. Gary P. Grim received his B.S. in mathematics from California State University, Chico in 1985, followed by his M.S. in 1992 and Ph.D. in 199) in experimental physics from the University of California, Davis. Grim’s graduate studies were in the field of particle physics, where he studied rare charm mesons decays as a test of electro-weak interaction theory within the standard model of particle physics. During his postdoctoral research in 1995–1999, Grim switched research groups at Davis and was an active participant in the design and construction of several semiconductor-based particle tracking detectors aimed at hadron collider experiments. These efforts included the CDF experiment at Fermi National Accelerator Laboratory and CMS experiment at CERN. During this time, Grim developed and tested the first data-driven pixel tracking telescope for use in high energy physics. In 2002, Grim joined the Physics Division staff at the Los Alamos National Laboratory. During his tenure at LANL, he has worked on a wide ranging set of projects and problems, including leading the design and construction of the National Ignition Facility neutron imaging diagnostic, as well as being a key player in the construction of a forward pixel detector for use at the PHENIX experiment at the RHIC facility sited at Brookhaven National Laboratory. Grim’s current efforts are focused on analyzing the data being produced by the NIF imaging diagnostics, as well as leading the development of new NIF diagnostic capabilities including the novel prompt-radiochemical assay techniques and gamma-ray imaging capabilities.

Abstract: Just past this centenary of the discovery of superconductivity, the design of new and more useful superconductors remains as enigmatic as ever. As high-density current carriers with little or no power loss, high-temperature superconductors offer unique solutions to fundamental grid challenges of the 21st century and hold great promise in addressing our global energy challenge in energy production, storage, and distribution. The recent discovery of a new class of high-temperature superconductors has made the community more enthusiastic than ever about finding new superconductors. Historically, these discoveries were almost completely guided by serendipity, and now, researchers in the field have grown into an enthusiastic global network to find a way, together, to predictively design new superconductors. I will share our general guidelines and hope to convey the renewed passion we share in this international pursuit. I will also share some of our advances in understanding the still-unknown mechanisms of high-temperature superconductivity by probing strong electronic correlations with quasiparticle scattering spectroscopy. Dr. Greene is Swanlund Professor of Physics and Center for Advanced Study Professor of Physics, Frederick Seitz Materials Research Lab, Center for Nanoscale Science and Technology, Department of Physics, University of Illinois, Urbana-Champaign; Co-Associate Director, Center for Emergent Superconductivity Energy Frontier Research Center. Her lecture was given on April 5, 2012.

Abstract: When relatively affordable femtosecond lasers became available, a whole new field opened for the computer-aided research in extreme nonlinear optics. As theorists adopted techniques originally designed for much longer times scales, it did not take long to realize that qualitative improvements were necessary in both the pulse propagation models and in the description of light-matter interactions. While significant progress was achieved in the former, state of the art in light-matter interaction modeling remains much less satisfactory. In this talk I will outline these developments, and focus on on-going efforts to meet the present challenge, which is to integrate Maxwell and Schroedinger systems. The quantum treatment of the medium response on one hand, and a fully resolved pulse propagation simulation on the other, require bridging vast disparities in scales. In learning how to do this, we find that some long established notions e.g., susceptibility or ionization rate, may not be applicable in ways we are used to.

Abstract: For over a thousand years, the field of optics has benefited from advances in materials and manufacturing technology. Recent advances in micro- and nanotechnology have led to a number of breakthroughs enabled by modern semiconductor processing techniques and advances in optical materials. This talk will explore a number of specific advances in optical technologies at Sandia National Laboratories enabled by the MESA facility. MESA is the U.S. government’s largest semiconductor manufacturing and research and development facility. It includes fabs for both silicon and III–V compound semiconductors in a 100K ft2 cleanroom. In addition to the fabs, MESA has over 100 light labs that both support and extract value from the fabs, and design, packaging, test and failure analysis capabilities to help migrate advances from basic research to production. This talk will explore a number of specific advances in optical technologies enabled by MESA (and by University of Arizona graduates and former faculty). Topics will include silicon and compound semiconductor photonics, photonic crystals, infrared metamaterials, plasmonics, nano-optomechanics, optical sensors, vertical cavity lasers, and micro-electromechanical systems.

Abstract: Advances in femtosecond lasers that have made it possible to generate pulses with durations on the order of one optical cycle have also made it possible to control the phase of the underlying electric field waveforms. This new capability is in turn leading to more accurate clocks and to greater precision in spectroscopy by creating broadband frequency combs. Further, by spatially resolving and rapidly modulating the many individual comb frequencies, one can generate truly arbitrary optical-frequency electric-field waveforms. This talk will describe advances toward these goals based on Ti:sapphire and fiber laser technologies to cover the wavelength range of 2µm–500nm. Erich P. Ippen received his Ph.D. from the University of California, Berkeley, in 1968 and worked at Bell Labs in Holmdel, N.J., from 1968 to 1980 before joining the faculty of MIT where he is now Elihu Thomson Professor of Electrical Engineering and professor of physics. He has received major awards from IEEE, the Optical Society (OSA), the American Physical Society and SPIE; and he is a member of the National Academy of Sciences, the National Academy of Engineering and the American Academy of Arts and Sciences. His current research interests include femtosecond optical clock and arbitrary waveform technologies, ultrashort-pulse fiber devices, ultrafast studies of materials and devices, and nanophotonics.

Abstract: Traditional CMOS and CCD imaging sensors capture two of the three fundamental properties of light: color and intensity. The third fundamental property of light, polarization, has been largely ignored by the imaging industry and research community in part by the human inability to “see” polarization properties. Nevertheless, polarization-contrast imaging has proven to be very useful in gaining additional visual information in optically scattering environments, such as target contrast enhancement in hazy/foggy conditions, depth mapping in underwater imaging, and in normal environmental conditions such as noncontact fingerprint detection, among others. Polarization imaging tends to provide information that is largely uncorrelated with spectral and intensity images. In this talk, I will present our latest research efforts in developing a division of focal plane imaging sensor capable of recording all three fundamental properties of light in high resolution and in real time. This sensor monolithically combines aluminum nanowires with CMOS imaging elements in order to create a spectral-polarization imaging sensor. I will cover both nanofabrication techniques as well as image processing algorithms that are mandated for these new types of sensors. I will conclude with examples of applications for this sensor in both medicine and biology.

Abstract: Precision optics manufacturing has evolved dramatically over the past few decades. For example, conventional pitch polishing has been used for decades with little change and is still the industry cornerstone for high-precision polishing and finishing. CNC polishing, single point diamond turning, magnetorheological finishing, and ion beam finishing are example of relatively new technologies that are increasing throughput, increasing precision, increasing determinism and/or enabling the finishing of more complicated geometries. This lecture will provide an overview of the latest manufacturing techniques for precision optics, focusing mainly on the polishing, finishing and metrology aspects of fabrication. It will focus more on “complex” and “traditionally difficult” geometries, as opposed to “standard spheres.” We will discuss the strengths and limitations of the various technologies and highlight how some optical designs that were previously considered cost-prohibitive or just plain impossible are becoming in reach of today’s optic shops. Aspheres represent a perfect example of one class of precision optics that has been hard to polish, hard to measure and, therefore, very expensive to manufacture. Their benefits to optical design (increased performance, reduced system weight, reduced system size) have been known for years but their use has only been exploited when their added cost could be justified. A transformation has occurred in infrared systems, where SPDT and profilometry can provide the necessary precision and flexibility to fabricate aspheres as cost effectively as spheres. As new technologies (such as those discussed in this lecture) become more pervasive, it is only a matter of time for similar transformations to occur in the higher precision visible and UV markets.

Abstract: What is a rainbow? How many are there? Why is the sky blue? Why is the setting sun red and flattened? What is a mirage? Why are there rays or spokes coming from the setting sun? What is the green flash? Can it be photographed? Why does the moon look so big on the horizon? Why do stars twinkle? What is an aurora borealis? Is it really darkest before dawn? Why are wet spots dark? What is that ring around the Sun? Why can water appear so many different colors? These and dozens of other questions about naturally occurring optical effects are explained with pictures and diagrams, along with tips on how to see and photograph them. Additionally, a number of curious optical phenomena which have not been well explained or merit further investigation will be shown. David Knight Lynch received a B.S. in Astrophysics in 1969 from Indiana University and a Ph.D. in Astronomy in 1975 from the University of Texas in Austin. He is Senior Scientist at The Aerospace Corporation where he specializes in infrared spectroscopy of comets, novae, supernovae, young stars and very old stars. Dr. Lynch has held research positions at the Sacramento Peak Observatory, Caltech, UC/Berkeley, and The Aerospace Corporation. He has published over 160 scientific papers and 10 books. He has organized 12 international scientific meetings. He is currently with the United States Geological Survey (USGS) in Pasadena, where he studies the San Andreas Fault.

Abstract: The beginning of the second decade of the 21st century has been characterized by a paradigm shift in the overall meaning of the term “information society.” First, “on-demand” communication and information exchanged at a variety of speeds, connection qualities, and underlying content has become vital. Since the Internet has become synonymous with the information era, significant efforts have been invested in making it flexible, universally accessible and affordable. Secondly, by 2015, IP traffic in the United States alone will reach an annual total of 1,000 exabytes, which is 50 times larger than the corresponding 2008 value. In response to this trend, rapid transition to a unified, high-speed packet-based core/edge network architecture, which extends all the way from data centers to both residential and business end-users, is being undertaken by major telecom carriers all around the globe. The current network must thus evolve into a dual-layer terabit Ethernet architecture that enables flexible data packet transport over fixed, high-speed optical bandwidth pipes. The fundamental question is thus how to reconcile the competing flexibility versus speed requirements, and provide sufficient on-demand bandwidth to each user, while also satisfying quality of service challenges and energy constraints. In this presentation, the key technologies, and practical considerations for realizing the next-generation terabit Ethernet based optical network will be discussed, along with a survey of state-of-the-art research activities and promising future directions in this area.

Abstract: Our long-term goal is to improve telepathology images for clinical use. Over the years we have carried out a series of studies addressing a variety of key issues associated with the interpretation of virtual pathology slides. These studies will be reviewed in this lecture. The initial studies were designed to demonstrate that diagnostic accuracy was equivalent between virtual and traditional (light microscopy) viewing. Then we sought to understand how pathologists view virtual slides in the digital reading environment using eye-position recording techniques. More recently we have investigated two aspects of image quality. In the first study we compared diagnostic accuracy using a color-calibrated, color-managed display compared to the same display without any special calibration (“out-of-the-box”). Surprisingly the sophisticated calibration technique had little to no impact on accuracy but did shorten viewing times somewhat. In another series of studies we have been investigating how much we can compress virtual slides before it impacts diagnostic accuracy. In these studies we also aim to demonstrate the utility of a visual discrimination model for predicting observer performance. In the most recent study, observer performance (Az) was nearly constant up to a compression ratio of 32:1, then decreased significantly for 64:1 and 128:1 compression. Virtual pathology may be compressible to relatively high levels before impacting diagnostic accuracy and the VDM accurately predicts human performance. An eye-position study followed demonstrating significant changes in scanning properties as a function of compression.

Abstract: Over seven million people die of cancer worldwide each year. The high mortality is mainly due to the lack of early cancer detection modalities, especially for internal organs. CT, MRI and ultrasound imaging have issues of low resolution, low contrast, safety or high cost. Several optical imaging techniques provide high-resolution cross-sectional information suitable for in vivo noninvasive early cancer diagnosis. However, these optical imaging systems are typically bulky and slow, and thus are difficult to apply to internal organs where most cancers are originated. Microelectromechanical systems technology offers the advantages of small size and fast scan speed, providing a tremendous opportunity for realizing real-time in vivo endoscopic imaging. In this talk, a unique MEMS technology that can create large-range, multi-axis, rapid scanning micromirrors and microlenses will be introduced. These MEMS devices in turn enable endoscopic optical “biopsy” modalities, resulting in a paradigm shift of optical imaging of internal organs. In particular, MEMS-based 3-D endoscopic optical coherence tomography imaging and confocal imaging will be introduced and in vivo experimental results of animals will be presented. Huikai Xie is a professor at the department of electrical and computer engineering of the University of Florida. He received his B.S., M.S. and Ph.D. degrees in electrical engineering from Beijing Institute of Technology, Tufts University and Carnegie Mellon University, respectively.

ln 1871, James Clerk Maxwell proposed a thought experiment, and in 1907, Albert Einstein made a prediction. Both men concluded that the experimental realizations would be impossible. ln this talk, I will describe our recent work that relates to this history, and show how it has enabled new methods for controlling matter with light. Prof. Mark G. Raizen is Sid W. Richardson Foundation Regents Chair Professor at UT-Austin.

Nanophotonics-based optical devices have a potential for wide variety of applications. For example, in next generation hard disk drives, a flying recording head with a nano-optical transducer creates a tiny near-field optical spot inside a magnetic recording medium which enables a higher data capacity per recording disk. As the example indicates, the “near-field” is a major application area for the nanophotonics devices. As one possible approach to apply them beyond the near-field, recently we demonstrated an array of photo electron transducer by using a novel C-shaped metallic nano aperture. The transducer creates sub-20 nm optical spots; then, the optical spots are converted to sub-20 nm electron sources. Such opt-electron combined imaging systems potentially break the near-field limitation by an aide of electron imaging optics. In the talk, we will describe operational principle and fabrication of the C-shaped nano aperture, experimental results on optical spot size and future applications.

Water probably flowed across ancient Mars, but whether it ever exists as a liquid on the surface today remains debatable. Recurring slope lineae are narrow (0.5 to 5 meters), relatively dark markings on steep (25° to 40°) slopes; repeat images from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment show them to appear and incrementally grow during warm seasons and fade in cold seasons. They extend downslope from bedrock outcrops, often associated with small channels, and hundreds of them form in some rare locations. RSL appear and lengthen in the late southern spring and summer from 48°S to 32°S latitudes favoring equator-facing slopes, which are times and places with peak surface temperatures from ~250 to 300 kelvin. Liquid brines near the surface might explain this activity, but the exact mechanism and source of water are not understood. Presented Thursday, Oct. 27, 2011

Optical imaging systems have evolved with the goal of producing an isomorphic measurement of a scene. Usually, such imaging systems place the sole burden of image formation on the optical front-end while the role of detector array is relegated to sampling and digitization of the optical image. Post-processing is typically viewed as a tool to mitigate image artifacts and noise, to apply compression and enable exploitation tasks such as pattern recognition, target tracking, etc. The traditional design approach optimizes each subsystem (optics, detector, post-processing) separately and often results in suboptimal designs. In contrast, computational optical imaging exploits the optical, detector and post-processing design degrees of freedom jointly to achieve end-to-end system optimality. Furthermore, such a design approach is especially suited to task-specific imaging as it allows one to incorporate knowledge of scene statistics and specific task in the system design. In this talk, I will discuss computational imaging system designs for two different tasks, image formation and pattern recognition, to illustrate the power of the joint-design framework. I will also talk about the emerging area of compressive imaging, where the number of measurement is much smaller than the inherent dimensionality of the scene, and its ability to significantly reduce the system's size, weight, power and cost. I will conclude by describing a task-specific information-theoretic approach to imaging system design and analysis in the context of fundamental limits of imaging systems.

Laboratory development of near-infrared fluorescence imaging and tomography for medical applications have been underway for some time. The technology is similar to nuclear medicine approaches in that photons which arise from the decay of a contrast agent administered in trace doses are detected to create an image or tomogram. NIRF imaging differs from conventional nuclear imaging technologies in that it requires the use of tissue penetrating, low energy excitation light to repeatedly activate NIRF contrast agents to acquire multiply scattered fluorescent light. Instrumentation, image reconstruction and imaging agents are dramatically different that in nuclear modalities, but potentially offer new opportunities to interrogate human disease that are not possible with any other imaging modalities. As an example, this presentation will describe translational NIRF imaging that enabled the first real-time visualization of lymphatic function in health and disease in over 200 human subjects. Emerging opportunities will be briefly discussed. Eva M. Sevick-Muraca earned her bachelor's and master's degrees at the University of Pittsburgh and her doctoral degree at Carnegie Mellon University. She has served on the faculties at Vanderbilt University, Purdue University, Texas A&M University and the Baylor College of Medicine, and she has received the National Science Foundation Young Investigator Award and the National Institutes of Health Research Career Award. In 1998, Sevick was elected a fellow of the American Institute of Medical and Biological Engineering.

Abstract: The design of the refracting telescope advanced rapidly following its invention in 1608, reaching its modern configuration in about a century. Even though the development of binoculars began almost simultaneously, nearly 300 years elapsed before practical prismatic binoculars became available. The impediments to practical binoculars were not only in optical design, but in mechanical design, manufacturing and materials. This talk will document the history of telescopes and binoculars from an engineering perspective looking at the evolution of basic optical system layout as well as some of the mechanical issues faced. This development will be illuminated using examples from the Museum of Optics at the College of Optical Sciences at the University of Arizona. Bio: John Greivenkamp is a professor of optical sciences at the University of Arizona, where he has taught courses in optical engineering since 1991. He is a fellow of SPIE and of the Optical Society (OSA). Greivenkamp is

Abstract: Terahertz technology has attracted intense interest recently due to its potential applications, from THz spectroscopy and imaging to homeland security. THz sources and detectors are critical for THz applications. Optical parametric process is one of the most promising approaches for tunable monochromatic THz generation and detection for THz applications. In this presentation, Dr. Shi will introduce several innovative results in THz generation and detection. He is the first to observe the THz generation based on DFG using GaSe crystals, and other his other breakthroughs include backward THz generation in GaSe and THz frequency upconversion in GaSe, ZnGeP2 and GaP, respectively. Most recently, Dr. Shi demonstrated fiber-based THz sources for the first time. Several new results about high-power THz generation, based on high power pulsed fiber lasers and some engineered nonlinear crystals, such as QPM-GaP and QPM-GaAs crystals, will be presented. Presented on Thursday, Sept. 15, 2011. Dr. Wei Shi is the director of pulsed fiber laser and THz technology at NP Photonics Inc. He also serves as adjunct professor at College of Optical Sciences at the University of Arizona and supervises graduate students from UA. Dr. Shi received his Ph.D. from State Key Laboratory of Crystal Materials in China and worked in this lab as an associate professor for three years. Dr. Shi has served on the program committee for nonlinear optics for Photonics West since 2008 and the subcommittee for THz technologies and applications for CLEO since 2000. He has served as session chair for CLEO and Photonics West many times since 2008. He is also topic editor for OSA's Applied Optics journal. He has more than 20 years of experience in lasers, nonlinear optics and optical amplifiers research and development. He is a pioneer for the high-power single-frequency pulsed fiber lasers/amplifiers, especially for high SBS-threshold fiber laser/amplifier. Dr. Shi is one of the world leaders for parametric THz generation and detection, especially for fiber-based tunable monochromatic THz sources. He has carried out over $5 million SBIR/STTR projects and other government contracts. He has over 90 journal papers and over 50 conference presentations (including one plenary talk and seven invited talks) at Photonics West, CLEO, OSA and SPIE meetings. Dr. Shi owns two U.S. patents and has three patents filed pending.

Dr. Sanjay Krishna is Professor, Department of Electrical and Computer Engineering; Associate Director, Center for High Technology Materials, University of New Mexico. Lecture presented Sept. 8, 2011. Infrared detectors operating in the 3-20 mm are important due to three main reasons. Firstly, the atmosphere is transparent in the two bands referred to as mid-wave infrared (MWIR, 3-5 mm) and long-wave infrared (8-12 mm), making it possible to see through fog and smoke under poor visibility conditions. Secondly, a lot of chemical species have characteristic absorption features in this wavelength range, making these detectors vital for remote sensing and stand-off detection. Finally, there is blackbody emission from living objects at these wavelengths, making it possible to use them for “night vision” and thermography applications such as surveillance and medical diagnostics. Presently, we are in what is referred to as the third generation of infrared detectors. The first generation of infrared detectors was based on single pixel and linear detector arrays. The second generation consisted of small format staring focal plane arrays. The emphasis of the third generation imagers is on (i) higher operating temperature, (ii) multicolor tunability and (iii) large format arrays. In this talk, I will try and look into the crystal ball to make predictions about the fourth generation of infrared detectors. Using the concept of a bioinspired infrared retina, I will make a case for an enhanced functionality in the pixel. The key idea is to engineer the pixel such that it not only has the ability to sense multimodal data such as color, polarization, dynamic range and phase but also the intelligence to transmit a reduced data set to the central processing unit. I will use two material systems, which are emerging as promising infrared detector technologies as prototypes to highlight this approach. These are (i) InAs/InGaAs self assembled quantum dots in well hetereostructure and InAs/(In,Ga)Sb strain layer superlattices (SLS) Detectors. Various approaches for realizing the infrared retina, such as plasmonic resonators[i], will be discussed. In addition to the applications of infrared imaging for defense application, I will highlight the role of infrared imaging in noninvasive medical diagnostics. In particular, I will highlight some work on using infrared imaging in the early detection of skin cancer. [i] S.J. Lee et al., Nature Communications, 2: 286 April 2011

The measurement of polarization information in optical imaging is made complicated by the fact that traditional optical detectors are polarization-blind and only measure intensity. In order to determine the polarization state of light across the scene, the intensity at each point must be modified in a controllable fashion over a series of measurements so that the distribution of polarization information can be inferred from these measurements. There are two general strategies for accomplishing this. The first method — generally referred to as wavefront division polarimetry — breaks the light into a series of channels, each with its own combination of polarization elements. The light in each of these channels is directed to an independent detector array, and the outputs are combined in order to estimate the polarization state. Wavefront division polarimeters have the advantage of obtaining the full space-time-wavelength resolution of the detectors. However, the disadvantage of such systems is the need for alignment, temporal synchronization and polarimetric aberration compensation across the channels. Additionally, there are practical limits to how many such channels can be put into a single system. The second strategy, and the one considered in this talk, is the class of modulated polarimeter that uses a single detector array to capture intensity information that has been modulated in space, time, wavelength or some combination of the three. Modulated polarimeters have the advantage of inherent spatial, temporal and wavelength alignment, but this comes at the expense of a reduction of the overall system bandwidth, since now a single detector is used to measure multiple channels.

nterest in a first-principles understanding of interfacial structure and dynamics of organic semiconductors has increased dramatically, driven, e.g., by vigorous efforts to develop platforms for efficient solar energy conversion. Understanding the effects of these interfaces remains, however, a formidable challenge, since interactions between chemically different molecules or molecules and surfaces may alter the molecular electronic structure in important ways. This is particularly true for the electronic structure and dynamics in the excited state manifold, where only few data are available. I will discuss several novel approaches developed in LabMonti towards understanding both electronic structure and dynamics at highly controlled interfaces, ranging from single molecule length-scales to time-resolved photoelectron spectroscopy in thin films. From such experiments emerges predictive insight into the interfacial electronic structure of organic semiconductors and novel ways of controlling and influencing charge transfer events towards efficient charge separation, currently thought to be one of the key obstacles in achieving higher solar energy conversion efficiencies.

Subwavelength-scale semiconductor nanolasers have received wide attention recently for their applications in optical interconnect, bio/chemical sensing, data storage and imaging. We are particularly interested in using nanolasers to reduce the energy consumption in on-chip interconnect. Though many optical sources have been demonstrated on Si, most of them are significantly larger than transistors, making them unattractive for integration with electronic circuits. At Berkeley, we have been developing near-infrared (1.3–1.55 um) semiconductor nanolasers with all three dimensions smaller than a wavelength. Using a nanopatch metalodielectric cavity, we observe lasing in the two most fundamental optical modes. To further reduce the optical mode volume, we have successfully demonstrated a plasmonic crystal laser. Experimental results will be presented.

Researchers at the Oak Ridge National Laboratory have developed a series of superhydrophobic (extremely water-repellent) materials and surfaces. This research and development effort began over five years ago with a goal of making a nanostructured material that would be the most water-repellent material theoretically possible — a material with a water contact angle very close to the theoretical limit of 180 degrees. The idea was to create an ideal nanostructured surface pattern that greatly amplifies the effect of water’s surface tension. Modeling and simulation results indicated that the ideal structure for water repulsion would be an ordered cone array. ORNL has created such an array structure (morphology) using fiber optic fabrication methods that turns a normally hydrophobic surface into the most hydrophobic surface fabricated to date. These surfaces turn water drops into nearly perfect spheres that bounce like rubber balls all over the surface until they finally bounce off. The water repulsion is so great that a layer of air gets physically trapped to the surface and remains on the surface even if the surface is totally submerged in water. The fabrication of this ideal cone structure was based on a modified version of existing microchannel plate fabrication techniques. This presentation will discuss how we fabricated these glass cone arrays, and the resulting superhydrophobic behavior of the arrays. The knowledge gained from this initial research effort has led to the creation of additional materials, structures and coatings that are not only superhydrophobic, but that are also much easier to fabricate than glass cone arrays and can be applied to virtually any surface. All these superhydrophobic materials and some of their potential applications will also be discussed and demonstrated. Presented March 10, 2011.

Multiplexed Föster resonant energy transfer imaging provides a systematic way to study signal networks that govern complex cellular processes. At present, real-time studying of these processes is limited by our inability to imaging the FRET network among four or more fluorescent labels simultaneously. The difficulty in multiplexed FRET rises from the complex photon pathway network in a multilabel FRET complex. To apply multiplexed FRET in live imaging, all photon pathways need to be imaged in parallel. We are developing a novel technique that measures fluorescence lifetime and intensity as images of excitation-emission matrices and fully analyzes all possible photon pathways within a single imaging scan in high speed. Quantitative analysis of lifetime EEM images will allow us to observe FRET between four or more labels in live samples, and therefore reconstruct the molecular machinery behind the multiplexed FRET phenomenon.

Over 30 years ago, researchers investigating the ultimate limits of mechanical detection of gravitational waves understood theoretically how quantum mechanics should limit these ultrasensitive mechanical measurements. In the past 10 years, the tools to prepare micron-scale mechanical structures in fundamental quantum states have been rapidly developed, using both optical and electrical techniques. In this lecture, I will give an overview of the state of the art from experiments in my group and around the world, focusing on the recent experiments to prepare the quantum ground state of motion and the success to produce superposition states in the laboratory. Presented Feb. 24, 2011.

Optical coherence tomography is one of the most rapidly developing biomedical imaging modalities. In this technique, the structural information is derived from the light backscattered or backreflected at the interfaces between the regions of different optical properties within the object. OCT technique enables two- or three-dimensional cross-sectional imaging with micrometer resolution. Recently, ultrahigh speed and ultrahigh resolution Spectral OCT imaging using CMOS and swept-source OCT has been demonstrated. Imaging speeds of more than 1,000,000 optical A-scans per second has been already achieved. High speed enables reducing motion artifacts and applying a high density sampling. Recent speed achievements in the high speed instrumentation open new perspectives for the further development of optical imaging modalities. The latter is especially important since OCT techniques can reveal and visualize such properties of biological objects as velocity of flow (via Doppler effect), birefringence (via polarization changes) and tissue extinction supplementary to the morphology. In my presentations I will give insight into the basics of OCT imaging modality to show the basic limitations and potential field of development of coherence imaging methods. I will also demonstrate new advancements of ophthalmic OCT instrumentation both in morphological and the functional imaging. I will also show how the speed and the resolution can be converted into a new quality of functional information by an efficient use of the phase and the amplitude of measured signal in Fourier domain systems.

Antennas are at the heart of modern radio and microwave frequency communications technologies. Because of their efficient coupling to light propagating in free space, antennas form the basis for transmitting and receiving electromagnetic radiation. Using metallic nanostructures, researchers have extended antenna concepts to the optical frequency domain and realized many advancements in nanophotonics [1]. However, recent research has begun to exploit the scattering resonances of high-permittivity particles to realize all-dielectric optical antennas. In this talk, we experimentally and theoretically characterize the resonant modes of subwavelength rod-shaped dielectric particles using Mie theory and infrared spectroscopy. We derive and verify a variety of general analytical results [2] applicable to all dielectric antenna systems and demonstrate novel antenna-based light emitters (transmitters) and photodetectors (receivers) [3,4]. External to the particle surface, the electromagnetic fields are indistinguishable from that of a point source and these structures can be thought of as artificial electromagnetic “atoms." Unlike real atoms, which resonate like electric dipoles only, dielectric antennas can be engineered to resonate in higher order modes. We discuss the distinct electromagnetic field profile for the observed antenna resonances and demonstrate that antennas can be arranged into a particle array to form an artificial electromagnetic material with a negative index of refraction [5]. Finally, we discuss how the concepts presented here may be extended to impact a variety of visible and infrared frequency photonic technologies.

Professor of Optometry and Vision Science and Affiliate Professor of Psychology and Engineering at the University of California, Berkeley Stereoscopic displays present different images to the two eyes and thereby create a compelling three-dimensional (3-D) sensation. They are being developed for numerous applications including cinema, television, virtual prototyping and medical imaging. However, stereoscopic displays cause perceptual distortions, performance decrements and visual fatigue. These problems occur because some of the presented depth cues (i.e., perspective and binocular disparity) specify the intended 3-D scene while focus cues (blur and accommodation) specify the fixed distance of the display itself. We have developed a stereoscopic display that circumvents these problems. It consists of a fast switchable lens (>1 kHz) synchronized to the display such that focus cues are nearly correct. The system has great potential for both basic vision research and display applications. I will discuss the optical properties of the display and how one might use this technology to produce a display that would be indistinguishable from the real world. I will also discuss recent research that shows that using multifocal technology improves visual performance and reduces visual fatigue.

The Multiangle Imaging SpectroRadiometer (MISR) instrument has been collecting global Earth data from NASA’s Terra satellite for more than a decade. With nine separate cameras, four visible/near-infrared spectral bands, and moderately high spatial resolution, MISR has demonstrated how multiangle intensity imaging offers unique tools for remote sensing of aerosol, cloud and surface properties. MISR observations of scattered light as a function of view angle and wavelength are used to retrieve aerosol amounts over the globe, including areas where separation of surface and aerosol signals is challenging (e.g., bright deserts). Partitioning into different aerosol types helps determine the concentration of fine airborne particulate matter, a regulated pollutant. MISR data show that bidirectional reflectances are sensitive to surface roughness over ice sheets and to the 3-D structure of vegetation canopies. Global stereoscopic imaging and automated pattern matching algorithms provide maps of cloud-top heights and wind vectors, and are being used to determine the heights of smoke plumes, volcanic plumes and dust clouds in many areas of the world.

I will describe recent experimental results, where we realize an asymmetric optical potential barrier for ultracold Rb 87 atoms using laser light tuned near the D2 optical transition. Such a one-way barrier, where atoms impinging on one side are transmitted but reflected from the other, is a realization of Maxwell's demon and has potential implications for cooling atoms and molecules not amenable to standard laser-cooling techniques. In our experiment, atoms are confined to a far-detuned dipole trap consisting of a single focused Gaussian beam, which is divided near the focus by the barrier. The one-way barrier consists of two focused laser beams oriented almost normal to the dipole-trap axis. The first beam is tuned to present a state-dependent potential to the atoms. The second beam pumps the atoms irreversibly to the proper state on the reflecting side of the barrier, thus producing the asymmetry. We study experimentally the reflection and transmission dynamics of ultracold atoms in the presence of the one-way barrier. I will also describe our longer-term interests and efforts towards quantum measurement and control of the center-of-mass motion of atoms, including some preliminary theoretical results on atomic dynamics under inhomogeneous position measurements.

Please enjoy Jim's unique insight into the history of — and the opportunities open to — our venerable institution.

We explore nonlinear optical phenomena at the nanoscale by launching femtosecond laser pulses into long silica nanowires. Using evanescent coupling between wires we demonstrate a number of nanophotonic devices. At high intensity, the nanowires produce a strong supercontinuum over short interaction lengths (less than 20 mm) and at a very low energy threshold (about 1 nJ), making them ideal sources of coherent white light for nanophotonic applications. The spectral broadening reveals an optimal fiber diameter to enhance nonlinear effects with minimal dispersion. We also present a device that permits a number of all-optical logic operations with femtosecond laser pulses in the nanojoule range.

Everyone knew it was coming because the microwave maser had proved the principle 10 years previous. But how to do it in the visible, at wavelengths 10,000 times shorter than microwaves? Ted Maiman got the glory with the ruby laser and Gordon Gould got the money for patents on optically pumped and gas discharge pumped lasers, as well as Brewster's angle laser windows.

The Shack-Hartmann wavefront sensor (SHWFS) has seen an increasing number of applications over the last 15 years. Originally used for high-energy laser adaptive optics, and then later applied to astronomy, more recently the numerous applications have been developed. The Shack-Hartmann wavefront sensor is used to measure the irradiance and phase distributions of an incident light beam by dissecting the income light with a lenslet array, and then detecting the direction of propagation by analyzing the focal spot pattern (detected with a CCD camera). Since the system is passive (that is, it measures any light that is incident, without the need for a reference beam), it can be used for a variety of situations where interferometry would be difficult. Applications include measurement and characterization of laser beams, optics, and optical systems, metrology of silicon wafers and ultraflat surfaces, as well as extremely rough (ground and machined) surfaces. A SHWFS was used to characterize missile seeker windows in a Mach 7 wind tunnel experiment. In another application, a LWIR sensor was used to measure the next space telescope (JWST) mirror segments during the fabrication process. Currently the most common application is the measurement of the human eye, where instruments based on this technology are used in thousands of clinics around the world. Dr. Neal will describe the basic technology, current implementations, and a number of diverse applications.

The concept of optical refrigeration (also known as laser cooling of solids) was described shortly after the birth of quantum mechanics. Interestingly, it was first rejected by many as unphysical and in violation of the laws of thermodynamics. The underlying mechanism is simple and based on anti-Stokes fluorescence where incident light from a coherent (low-entropy) source such as a laser is upconverted into high-entropy fluorescence via absorption or removal of vibrational energy (phonons). Some have called this phenomenon “a laser running in reverse." Since its first experimental observation in 1995, optical refrigeration has advanced greatly. Recently, crystals doped with Yb ions have cooled to an absolute temperature of 155K starting from room temperature, with even lower temperatures possible. Optical refrigeration is the only available technique for attaining cryocooling with an entirely solid-state device. In this talk, I will introduce and review the field, including efforts to attain net cooling in semiconductors. Progress has been driven by materials engineering with emphasis on high quantum efficiency and low parasitic background absorption.

Multiterawatt femtosecond duration laser pulses, when launched in the atmosphere, undergo extreme self-focusing to produce dramatic spectral superbroadening and breakdown the molecular constituents of air to produce extended electron-ion plasma channels. The dramatic nonlinear events occurring in the interaction zone while only qualitatively understood, have prompted a flurry of activity over the past decade into exploiting these phenomena in real-life applications. Some applications include femtosecond atmospheric lidar, remote detection of pollutants and/or chem/bio agents, remote laser induced breakdown spectroscopy (LIBS), control of lightning and remote terahertz spectroscopy. The University of Arizona is the lead institution in a new Multi-disciplinary University Research Initiative (MURI) project along with five other institutions. The goal is to gain a deeper understanding of the complex nonlinear physics involved and build mathematically rigorous and computationally feasible models of intense pulse filamentation in air and condensed media. In this talk, I will present a brief history of the development of this emerging field of nonlinear science, point to some successes achieved along the way and outline the strategy of the MURI team aimed at solving remaining outstanding problems. The Arizona team has been to the forefront in developing the present theoretical foundation and more recently we have built a TW femtosecond laser laboratory to support the theory and simulation effort. One intriguing departure from the status quo is to envisage laser beam profiles constituted from linear superpositions of conical waves. Such beams (Bessel and Airy) are remarkably robust under propagation and exhibit a self-healing property which is fundamentally different behavior from that of conventional Gaussian beams.