Advanced Devices and Sensors Through Ultrathin Metasurfaces
September 18th, 2017 J. SEBASTIAN GOMEZ University of California

The exponential expansion of the information society is continuously imposing stringent – and sometimes even contradictory – technological requirements to modern communication systems, including high communication data rates, efficient use of the spectrum, ubiquitous wireless connectivity, and many functionalities integrated into reconfigurable, miniaturized, and wearable devices and sensors. In this talk, I will discuss the possibilities offered by ultrathin nanostructured surfaces to address these challenges and exhibit exciting functionalities thanks to the use of tunable, active, and nonlinear materials and enhanced wave–matter interactions. I will first focus on graphene and other 2D materials as a powerful reconfigurable platform for THz and infrared plasmonics, describing components like modulators and antennas as well as hyperbolic metasurfaces enabling unprecedented near-field responses such as plasmon tunneling and canalization, SER enhancement, super Planckian thermal radiation, and in–plane giant optical forces. Next, I will present magnetic-free non-reciprocal plasmonic and photonic devices and antennas based on the spatiotemporal modulation on graphene’s conductivity, analyzing their exciting properties and investigating novel routes towards optimal designs. Then, I will introduce a ‘flat non-linear paradigm’ able to simultaneously exhibit a record high second-order nonlinear response from plasmonic metasurfaces tied to multi–quantum wells and sub–diffractive phase control. Such combination paves the wave to the efficient generation of pencil–beams steered in arbitrary direction in space, vortex beams, and focusing. The last part of the talk will be devoted to ultra-fast infrared sensors that combine nanomechanical resonators with ultrathin nanostructures, providing unprecedented electromechanical performance and thermal capabilities. We are currently applying this technology to develop portable, label–free, low–cost, accurate, infrared and terahertz biosensors. I will finalize by describing the near and long–term potential impact of ultrathin metasurfaces in industry and information society. Juan Sebastian Gomez Diaz is an Assistant Professor in the Electrical and Computer Engineering Department of the University of California, Davis. He received the PhD. degree in electrical engineering from the Technical University of Cartagena, Spain, in 2011. From October 2011 until March 2014 he was a postdoctoral fellow at the École Polytechnque Fédéral de Lausanne (EPFL, Switzerland). Then, from May 2014 to August 2016, he continued his postdoctoral work in the Metamaterials and Plasmonic Research Laboratory of The University of Texas at Austin (US). His main research interests include multidisciplinary areas of electromagnetic wave propagation and radiation, metamaterials and metasurfaces, plasmonics, 2D materials, non-linear phenomena, antennas, and other emerging topics on applied electromagnetics and nanotechnology.

Seminar, September 18, 2017, 12:00. ICFO Seminar Room

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