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November 7, 2012


Kenneth L. Knappenberger, Jr.
Assistant Professor of Chemistry and Biochemistry
Florida State University

"Structure-­dependent Nanoparticle Plasmonics"
4:10 pm, 5326 Stevenson Center

 I will highlight recent advances toward predictive descriptions of  the nanoparticle structure-property interplay using single-particle nonlinear optical (NLO) spectroscopy techniques in combination with 3-D electron tomography methods.  Polarization-resolved second harmonic generation (SHG) measurements were performed on solid gold nanosphere (SGN) dimers at the single-particle level.  The results indicated that single-particle SHG measurements could be used to quantify the localized electronmagnetic surface fields that result from excitation of inter-particle localized surface plasmon modes.  For several dimers, the polarization resolved measurements revealed that the surface fields localized between SGNs in a dimer were chiral.  Quantitative analysis of SHG line shapes obtained from single-particle continuous polarization variation (CPV-SHG) experiments confirmed that the chirality originated from non-zero magnetic-dipolar contributions to the SGN dimer nonlinear optical response.  Correlation of electron microscope images and single-particle SHG measurements obtained for several SGN dimers, as well as lithographically generated nanostructures, were used to demonstrate the structure sensitivity of the CPV-SHG method.

Host: Richard Haglund

K. Knappenberger
Vanderbilt University