ECE PhD Final Thesis Defense Announcement: Ren Wang, February 21st, 9AM-11AM

  • Starts: 9:00 am on Wednesday, February 21, 2018
  • Ends: 11:00 am on Wednesday, February 21, 2018
Presenter: Ren Wang Date: Feb-21-2018 Time: 9:00-11:00AM Location: PHO-940 Chair: Chen Yang Advisor: Luca Dal Negro (ECE, MSE, Physics) Committee: Anna Swan (ECE, Physics, MSE), Alexander Sergienko (ECE), Enrico Bellotti (ECE, MSE) Abstract: Designing photonic-plasmonic nanostructures with desirable electromagnetic properties is a central problem in modern photonics engineering. As limited by available materials, engineering geometry of optical materials at both element and array levels becomes the key to solve this problem. In this thesis, I present my work on the development of novel methods and design strategies for photonic-plasmonic structures and metamaterials, including novel Green’s matrix-based spectral methods for predicting the optical properties of arbitrary large-scale nanostructures. From engineering elements to arrays, I begin my thesis addressing toroidal electrodynamics as an emerging tool to enhance light absorption in designed nanodisks by geometrically creating anapole configurations using high-index dielectric materials. This work demonstrates enhanced absorption rates designed by multipolar decomposition of current distributions involving toroidal multipole moments for the first time. I also present my work on designing helical nano-antennas using rigorous Surface Integral Equations method. The helical nano-antennas feature unprecedented beaming-forming and polarization tunability controlled by their geometrical parameters, and can be understood from the array perspective. In these two projects, optimization of optical performances are translated into systematic study of identifiable geometric parameters. However, while array-geometry engineering presents multiple advantages, including physical intuition, versatility in design, and ease of fabrication, there is currently no rigorous and efficient solution for designing complex resonances in large-scale systems from an available set of geometrical parameters. In order to achieve this important goal, I developed an efficient numerical code based on the Green’s matrix method for scattering by arbitrary arrays of coupled electric and magnetic dipoles, and show its relevance to the design of light localization and scattering resonances in deterministic aperiodic geometries. I will show how universal properties driven by the geometries of the scattering arrays can be deduced through studying the spectral statistics of the corresponding Green’s matrices and how this approach leads to novel metamaterials for the visible and near-infrared spectral ranges. Within the thesis, I also provide my numerous related works as examples specific to designing and inverse-designing photonics applications, including plasmonic sensing, optical antennas, radiation shaping, and photodetectors, which directly rely on the numerical methods and approaches developed during my research.
8 Saint Mary's St. Boston, MA Room 940

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