“Transparent Conducting Oxide Active Plasmonics and Metasurfaces: Ultrasmall and Ultrathin Optics

By Dr. Howard (Ho Wai) Lee,
Postdoctoral Scholar,
Thomas J. Watson Laboratory of Applied Physics,
California Institute of Technology

Monday, April 27th, 2015 from
3:05 – 3:55 p.m. in WEB 1230


Controlling the flow of light at the nanoscale is fundamental to optical applications. Plasmonics, the sub-wavelength surface electromagnetic waves that are guided on a metal-dielectric interface, enable a promising approach for achieving the downscaling of light due to its extreme light confinement. However, current plasmonic structures encounter significant limitations due to (1) high optical losses and (2) the lack of efficient tunability. In this talk, I will present the use of alternative low-loss plasmonic materials, i.e., transparent conducting oxides, to actively control the optical properties of plasmonic and metasurface structures, allowing us to study the fundamental nature of light-matter interactions and apply it to emergent optical phenomena of novel optical applications.

I will first present the use of tunable low-loss active materials, transparent conducting oxides, to demonstrate an efficient plasmonic modulation that operates via solid-state MOS field-effect dynamics [1], and an electrically driven plasmonic resonant structure that can tune the optical dispersion [2]. I will then discuss the integration of very different but remarkably sciences, plasmonics and photonic crystal fiber optics, for the development of a new class of hybrid plasmonic/ photonic waveguides. Such hybrid “nanostructured”-fibers provide a promising unique platform with controllable optical dispersion and long interaction lengths for the investigation of plasmonic/metamaterial optical properties and the realization of novel in-fiber applications [3, 4]. Finally, I will discuss the advantages of integrating conducting oxides with metallic nanoantenna to develop tunable metasurfaces for next-generation nano-optical components, such as ultrathin tunable optical lenses, beam steering or spectral splitting elements.


Dr. Howard Lee is a Postdoctoral Fellow at California Institute of Technology, working with Professor Harry Atwater in the Applied Physics and Materials Science Department.  He received his PhD in Physics from the Max Planck Institute for the Science of Light in Germany in 2012 under the supervision of Professor Philip Russell. His research focuses on developing new techniques, including novel active materials and nanostructures, to actively control the optical properties of plasmonic and metamaterial structures for studying new optical physics and light-matter interaction at the nanometer scale, as well as advancing novel optical components with new functionality. His work on nano-optics, plasmonics and photonic crystals has led to 18 papers published in various journals, such as Science, Nano Letters, Advanced Materials, Optics Letters and Applied Physics Letters, as well as 50 conference papers.