Chairs
Professor Ortwin Hess, Imperial College London, UK
Professor Ortwin Hess, Imperial College London, UK
Professor Ortwin Hess holds the Leverhulme Chair in Metamaterials in the Department of Physics at Imperial College London and is Co-Director of the Centre for Plasmonics & Metamaterials. Professor Hess studied physics at the University of Erlangen and the Technical University of Berlin. Following pre- and post-doctoral times in Edinburgh and at the University of Marburg, Hess has been (from 1995 to 2003) Head of the Theoretical Quantum Electronics Group in Stuttgart, Germany and after the Habilitation in Theoretical Physics (1997) and became Adjunct Professor at the University of Stuttgart in 1998. Professor Hess has been Visiting Professor at Stanford University and the University of Munich. From 2003 to 2010 he was Professor in the Department of Physics and the Advanced Technology Institute at the University of Surrey in Guildford, UK. Professor Hess's research interests and activities are in condensed matter quantum optics and are currently focused on quantum and nano-photonics, nanoplasmonics and metamaterials, spatio-temporal laser dynamics and computational photonics.
09:00-09:30
Device applications of metafilms
Professor Mark Brongersma, Geballe Laboratory for Advanced Materials, USA
Abstract
Many conventional optoelectronic devices consist of thin, stacked films of metals and semiconductors. In this presentation, I will demonstrate how one can improve the performance of such devices by nano-structuring the constituent layers at length scales below the wavelength of light.
The resulting metafilms and metasurfaces offer opportunities to dramatically modify the optical transmission, absorption, reflection, and refraction properties of device layers. This is accomplished by encoding the optical response of nanoscale resonant building blocks into the effective properties of the films and surfaces. To illustrate these points, I will show how nanopatterned metal and semiconductor layers may be used to enhance the performance of solar cells, photodetectors, and enable new imaging technologies. I will also demonstrate how the use of active nanoscale building blocks can facilitate the creation of active metafilm devices.
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Professor Mark Brongersma, Geballe Laboratory for Advanced Materials, USA
Professor Mark Brongersma, Geballe Laboratory for Advanced Materials, USA
Mark Brongersma is a Professor in the Departments of Materials Science and Engineering and Applied Physics at Stanford University. He received his PhD from the FOM Institute in Amsterdam, The Netherlands, in 1998. From 1998-2001 he was a postdoctoral research fellow at the California Institute of Technology. His current research is directed towards the development and physical analysis of nanostructured materials that find application in nanoscale optoelectronic devices. He has authored\co-authored over 160 publications, including papers in Science, Nature Photonics, Nature Materials, and Nature Nanotechnology. He also holds a number of patents in the area of Si nanophotonics and plasmonics. Brongersma received a National Science Foundation Career Award, the Walter J. Gores Award for Excellence in Teaching, the International Raymond and Beverly Sackler Prize in the Physical Sciences (Physics) for his work on plasmonics, and is a Fellow of the Optical Society of America, the SPIE, and the American Physical Society.
09:45-10:15
Dielectric Huygens metasurfaces – fundamentals and applications
Professor Dragomir Neshev, Australian National University, Australia
Abstract
The concept of Huygens metasurfaces has recently emerged as a powerful platform for complete manipulation of light properties, including phase, amplitude, polarisation, and even colour. Their operation is based on the interference of the electric and magnetic dipolar responses of the constituent metasurface elements, called meta-atoms, such that they can only scatter in forward direction, while back-scattering is inhibited. Dielectric Huygens metasurfaces stand out as a prominent example, due to their negligible optical losses and easy fabrication. Such dielectric metasurfaces are composed of small high-refractive-index nano-particles, which exhibit Mie-type resonances of both electric and magnetic origin and comparable strength. By designing the geometry of the individual meta-atoms it is possible to exactly match the spectral position of these resonances, thus enabling unitary transmission through the Huygens metasurface, while simultaneously being able to control the phase of transmitted light in the full range of 0-2π.
This talk will review the fundamental designs and principles of operation of such dielectric metasurfaces, as well as will overview the plethora of their functionalities, including frequency selectivity, wavefront shaping, and polarization control. In particular, we demonstrate experimentally beam shaping in complex holographic shapes with near unity transmission efficiency. We further utilise our Huygens metasurfaces for generation of beams carrying orbital angular momentum, including vortex and vectors beams with azimuthal/radial polarisations operating over a broad spectral range. Finally, we will present some of their recent applications in nonlinear light sources, biosensing, and quantum optics.
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Professor Dragomir Neshev, Australian National University, Australia
Professor Dragomir Neshev, Australian National University, Australia
Dragomir Neshev received the PhD degree in physics from Sofia University, Bulgaria in 1999. Since then he has worked in the field of nonlinear optics at several research centres around the world. From 2002, he is with the Australian National University (ANU), where he is currently a Full Professor and leads the Experimental Photonics group at the Nonlinear Physics Centre. He is the recipient of a number of awards, including a Queen Elizabeth II Fellowship (ARC, 2010); an Australian Research Fellowship (ARC, 2004); a Marie-Curie Individual Fellowship (European Commission, 2001); and the Academic award for best young scientist (Sofia University, 1999). His activities span over several branches of optics, including optical metamaterials, plasmonics, singular optics, and nonlinear periodic structures.
11:00-11:30
Silicon-based metasurfaces for near-infrared optics
Professor Jason Valentine, Vanderbilt University, USA
Abstract
Absorption loss continues to be one of the primary impediments to the application of plasmonic metamaterials and metasurfaces at optical frequencies. Dielectric metamaterials offer one potential solution to this issue by eliminating ohmic loss, allowing the realization of highly transparent materials. As with their plasmonic counterparts, manipulation of the unit cell structure of all-dielectric metasurfaces also offers a means to engineer a wide variety of optical functionalities.
In this talk, I will discuss our recent experimental efforts to demonstrate silicon-based metasurfaces within the telecommunications band. I will talk about how simple unit cell geometries allow these metasurfaces to be scaled to large areas using self-assembly based patterning techniques. Importantly, defects in such materials are found to have little effect on the performance of the surfaces. On the other hand, I will discuss how more complicated unit cells can be used to realize wavefront control as well as high quality factor resonances. The high-Q resonances can be used for sensing and the large local field enhancement within the silicon unit cells results in a third harmonic conversion enhancement factor of 105 with respect to an unstructured silicon slab. Such surfaces could potentially be applied for all-optical switches in the future.
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Professor Jason Valentine, Vanderbilt University, USA
Professor Jason Valentine, Vanderbilt University, USA
Professor Valentine received a B.S. in mechanical engineering from Purdue University in 2004 and a Ph.D. in mechanical engineering from UC Berkeley in 2010. In 2010 he joined the faculty in the Mechanical Engineering Department at Vanderbilt University as an Assistant Professor. Prof. Valentine's past and current work includes the development of bulk plasmonic optical metamaterials, transformation inspired devices such as optical cloaks, dielectric metamaterials at optical frequencies, and hot electron devices. His work was selected by Time Magazine as one of the "Top 10 Scientific Discoveries in 2008". At Vanderbilt he has received an NSF CAREER Award and the Office of Naval Research Young Investigator Award for research on dielectric metamaterials.
11:45-12:15
Active graphene-integrated plasmonic metasurfaces and their applications: from motion detection to polarization control of infrared light
Professor Gennady Shvets, The University of Texas at Austin, USA
Abstract
Plasmonic metasurfaces enhance light-matter interaction by focusing light into extremely subwavelength dimensions. These carefully designed structures have been used in extremely thin optical component which can mold the wavefront, with exciting applications in optical lenses, beam steering, and biosensing applications. Adding dynamic tunability to these devices opens up the possibility for new application in single pixel detection and 3D imaging as well as optical modulators and switches. However the existing approaches for designing active optical devices in infrared, are either slow or have small refractive index change. Integrating plasmonic metasurfaces with single-layer graphene (SLG) opens exciting opportunities for developing active plasmonic devices because the amplitude and phase of the transmitted and reflected light can be rapidly modulated by injecting charge carriers into graphene using field-effect gating. I will describe our recent experimental results demonstrating strong phase modulation of mid-infrared light. The phase shifting due to electric gating of the SLG was measured using a Michelson interferometer, and further utilized to demonstrate an electrically controlled (i.e. no moving parts) interferometry capable of measuring distances with sub-micron accuracy. Because of the potentially nanosecond-scale measurement time, active metasurfaces represent a promising platform for ultra-fast standoff detection. Finally, we demonstrate that, by the judicious choice of a strongly anisotropic metasurface, the graphene-controlled phase shift of light can be rendered polarization-dependent, thereby modulating the polarization state (e.g., the ellipticity) of the reflected light. These results pave the way for novel high-speed graphene-based optical devices and sensors such as polarimeters, ellipsometers, and frequency modulators.
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Professor Gennady Shvets, The University of Texas at Austin, USA
Professor Gennady Shvets, The University of Texas at Austin, USA
Gennady Shvets is a Professor of Physics at The University of Texas at Austin. He received his PhD in Physics from MIT in 1995. He has been on the Physics faculty at the University of Texas at Austin since 2004. Previously he has held research positions at the Princeton Plasma Physics Laboratory and the Fermi National Accelerator Laboratory, and was on the faculty of the Illinois Institute of Technology. His research interests include nanophotonics, optical and microwave metamaterials and their applications (including bio-sensing, optoelectronic devices, and vacuum electronics), and plasma physics. He is the author or coauthor of more than 160 papers in refereed journals, including Science, Nature Physics, Nature Materials, Nature Photonics, Physical Review Letters, and Nano Letters. Dr. Shvets was a Department of Energy Postdoctoral Fellow in 1995-96. He was a recipient of the Presidential Early Career Award for Scientists and Engineers in 2000. He is a Fellow of the American Physical Society (APS) and Optical Society of America (OSA). His research is currently supported by various government agencies, including National Institute of Health, Department of Energy, National Science Foundation, Air Force Office of Scientific Research, and Office of Naval Research.
Professor Shvets is one of the pioneers in the emerging field of plasmonic metamaterials, especially in the infrared part of the spectrum. He and his colleagues were the first to experimentally implementing the concept of the Infrared Perfect Lens based on polaritonic materials (SiC), and the first to experimentally investigate optical properties of the so-called hyperbolic metamaterials that enable the propagation of sub-diffraction light waves. His group’s theoretical research addressed some of the most basic questions in metamaterials, including bi-anisotropy, homogenization, and Fano resonances. His most recent work deals with the applications of metamaterials and plasmonics to infrared light generation and harvesting, concentrated solar energy and thermo-photovoltaic systems, biosensing and molecular fingerprinting of proteins and live cells using metamaterial arrays, optical imaging with sub-diffraction resolution using nanoparticle labels, photonic topological insulators, graphene-based metamaterials, and electron beam-driven metamaterials. He is particularly interested in the integration of metamaterials and metasurfaces with various applications-specific platforms such as microfluidics, and in developing metamaterials-inspired devices that utilize non-traditional active, nonlinear, and low-loss materials such as graphene, quantum dots, silicon, and silicon carbide.