Dresden 2009 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 20: Nano-optics of metallic and semiconducting nanostructures (time resolved)

O 20.5: Vortrag

Dienstag, 24. März 2009, 11:30–11:45, SCH A216

Ultrafast Coherent Control of Third-Harmonic Generation in Plasmonic Nanostructures — •Tobias Utikal^1,3, Mark I. Stockman^1,2, Albert P. Heberle¹, Markus Lippitz³, and Harald Giessen¹ — ¹4. Physikalisches Institut, Universität Stuttgart — ²Department of Physics and Astronomy, Georgia State University, USA — ³MPI für Festkörperforschung, Stuttgart

We present a new technique to coherently control ultrafast nonlinear plasmonic effects on a nanometer scale. By using a nonlinear four-photon process (third-harmonic generation) our detection is not limited to the local optical intensity in the system, but additionally supports phase information. The nanostructure under investigation consists of a 1-D gold wire grating on top of a dielectric slab waveguide. The coupling of particle plasmons, optically excited in the wires, to photonic waveguide modes leads to plasmon-polaritonic eigenstates, characterized by long dephasing times, whose dynamics can be coherently controlled on a femtosecond timescale. In the experiment one polaritonic eigenstate is excited by a first sub-8 fs laser pulse (start pulse). A subsequent second pulse (control pulse) follows the start pulse after a few tens of femtoseconds. Dependent on the exact phase delay, the control pulse either stops the polariton oscillation or re-excites it again. A third pulse (probe pulse), which is aligned at a small angle to the start and control pulse, is continuously shifted in time. Photons of the probe pulse together with photons of the start and control pulse create a nonlinear third-harmonic signal depending on the coherently controlled polarization of the polariton.