Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 20: Nano-optics of metallic and semiconducting nanostructures (time resolved)
O 20.4: Vortrag
Dienstag, 24. März 2009, 11:15–11:30, SCH A216
Enhancing optical near-fields in nanoantennas via shaped ultrashort laser pulses — •Christian Rewitz1, Philip Tuchscherer1, Dmitri V. Voronine1, Andreas Reiserer1, Jer-Shing Huang2, Bert Hecht2, and Tobias Brixner1 — 1Institut für Physikalische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — 2Nano-Optics and Biophotonics Group, Department of Experimental Physics 5, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
Femtosecond laser pulse shaping has been developed into an efficient tool for the manipulation of interference phenomena on the nanoscale. We show that this technique can be applied to tailor the ultrafast temporal response of the strongly confined and enhanced optical near-fields in the feed gap of resonant optical antennas.
Using finite-difference time-domain (FDTD) simulations followed by Fourier transformation, we obtain the impulse response of a nanostructure in the frequency domain, which allows obtaining its temporal response to any arbitrary pulse shape.
Additionally to this deterministic approach, an adaptive scheme involving an evolutionary algorithm can be used to obtain the optimal spectral phase that pre-compensates for the dispersion induced by the antennas. Comparing deterministic and adaptive results allows for a better understanding of plasmonic resonances in nanostructures. The presented control mechanisms will be of importance for experiments involving light-induced processes in nanometer-scale volumes.