Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 32: Plasmonics and Nanophotonics II (Joint Session O/DS/HL)
O 32.4: Talk
Tuesday, March 23, 2010, 15:45–16:00, H2
Ultrafast optical nonlinearities in hybrid metal-semiconductor nanostructures — •Parinda Vasa1, Robert Pomraenke1, Wei Wang1, Stephan Schwieger2, Erich Runge2, and Christoph Lienau1 — 1Carl von Ossietzky Universitaet, Institut fuer Physik, 26111 Oldenburg, Germany — 2Technische Universitaet Ilmenau, Institut fuer Physik, 98684 Ilmenau, Germany
Understanding and manipulating the interactions between quantum emitters and Surface Plasmon Polaritons (SPPs) is the key to designing and implementing novel nano-optical devices such as nanolasers or ultrafast optical switches. We report the first measurement of an ultrafast optical nonlinearity resulting from the strong interaction between SPPs excited on a gold grating and excitons in either a semiconductor QW or a J-aggregated cyanine dye. The hybrid nanostructures are characterized using far-field linear reflectivity as well as photoluminescence measurements and exhibit enhanced SPP-exciton coupling in the linear optical regime. The experimental results are explained within a phenomenological, coupled oscillator model. The nonlinearity is investigated by low-temperature, angle-resolved, ultrafast pump-probe spectroscopy with 20-fs-time resolution. Due to the strong coupling a significant shift in the resonance wavelength and changes in the response time of the third order nonlinearity of the exciton are observed. Such a strong ultrafast nonlinear interaction between metal and excitons will be of key importance to amplify SPP excitations in such hybrid structures.