추가 정보 영역
| Speaker |
S. Joon Kwon, Ph.D. |
| Affiliation |
Nanophotonics Research Center, Korea Institute of Science and Technology (KIST) |
| Date |
May 31, 2017 |
| Time |
4:00 pm - 5:00 pm |
| Venue |
EB2 E101 |
| Sponsor |
UNIST-Energy and Chemical Engineering |
| Host |
Prof. So Youn Kim |
| Contact |
052-217-2558 |
| Phone |
052-217-3552 |
Ever since theoretically proposed, Anderson localization has been studied in a variety of areas concerning localized wave phenomena in a random media from acoustic waves to quantum waves. Due to strong localization of waves, it has been conjectured that the constructive interferences of diffused electromagnetic waves as a form of accumulated multiple scattering in a disordered sub-wavelength nanostructures can contribute to the enhancement of near-field in 2D plane supporting strong plasmonic effects. In this study, we demonstrated disordered plasmonic media comprised by sub-wavelength metallic nanoparticles or nanowires network. The disordered nanostructures are deliberately designed to induce and localize two- or three-order enhanced near-field. The induced field finally results in two- or three-order enhanced intensity of emitted light by the near IR-to-visible light upconversion (UCL). In order to form plasmonic ‘hot-spots’, we fabricated self-assembled array of sub-100 nm Ag nanoparticles over a plasmonic substrate containing β-NaYF4:Yb3+/Er3+ UC nanoparticles. We also employed a randomly aligned network of micrometer-long Ag nanowires as sub-wavelength Fabry-Perot resonance mode supporting plasmonic substrate. We experimentally and computationally observed and confirmed the formation of strong near-field of incident near IR at 980 nm around the respective nanostructures. We also observed reinforced near IR light absorption and green and red visible light emission by nano-antenna effects given by the randomized nanostructures for the plasmonic configurations. The strong near-field formation and enhanced UCL was effectively explained in the framework of the Anderson localization. We expect further editing and modifying of the plasmonic nanostructures pursuing better light extraction for various light emitting devices involving UCL.
