Institute of Physics, University of Graz, Austria

Abstract:
Surface plasmons are mixed photon/electron modes at the interface of a metal and a dielectric. When sustained by metal nanostructures, plasmonic excitations enable to focus light down to the nanoscale, accompanied by a resonant local field enhancement, viz., enhanced local mode densities. These properties make surface plasmons an appealing base for biosensing applications, relying on either refractive index contrast or the increased excitation and emission rates of some elementary emitter. I will, first, discuss some recent developments in our fundamental understanding of plasmonic nanoparticles and -wires, based on optical scattering measurements [1] and electron energy loss spectroscopy [2]. Second, I will emphasize the role played by particle shape and the according plasmon field profile on the sensing signal by discussing DNA hybridization on differently shaped nanoparticles [3]. Third, I will propose a surface plasmon resonance sensing scheme relying on grating coupling to short-range plasmons with regular arrays of plasmonic nanoparticles on flat metal films [4].
[1] A. Truegler et al., Influence of surface roughness on the optical properties of plasmonic nanoparticles, Phys.Rev.B 83, 081412(R) (2011)
[2] U.Hohenester, H.Ditlbacher, J.R.Krenn, Electron energy loss spectra of plasmonic nanoparticles, Phys.Rev.Lett. 103, 106801 (2009)
[3] M. Piliarik et al., Local refractive index sensitivity of plasmonic nanoparticles, Opt.Express 19, 9213 (2011)
[4] A.Hohenau, J.R.Krenn, Plasmonic modes of gold nano-particle arrays on thin gold films, Phys.Stat.Sol. (RRL) 4, 256 (2010)

报告人简介：
Dr. Joachim R. Krenn is a Professor in Experimental Physics in Institute of Physics, Karl-Franzens-University in Austria. He received his Ph.D. from Karl-Franzens-University in 1997, and become an associate Professor in 2001. Dr. Krenn has served as Invited Professor of several universities since 2002, and was the Head of the Institute for Nanostructured Materials and Photonics, Joanneum Research Forschungsgesellschaft (Weiz, Austria) between 2007 and 2010. Since March 2011, he became Full Professor at the Karl-Franzens-University, Graz. He was a guest editor for IEEE Journal of Selected Topics in Quantum Electronics from 2006 to 2008, and now, is an editorial board member of Applied Physics A, Springer and Plasmonics, Springer. He was awarded the Scholarship of the Region of Burgundy, France in 1998 and Styrian Research Award for Nanoscience and Nanotechnology in 2003.
Prof Krenn’s research interests are focused on nanooptics, plasmonics, optoelectronics of nanoscale systems, optical sensors, micro- und nanostructuring, quantum emitters in nanoscale systems, surface enhanced spectroscopy and ultrafast electron dynamics in metals. He has published more than one hundred scientific journal articles and five book chapters with citations over 6000 times, and has given 40 invited conference talks.

联系人：金奎娟 研究员（82648099）
报告邀请人：徐红星 研究员（82648091）