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O: Oberflächenphysik
O 34: Rastersondentechniken II
O 34.6: Vortrag
Montag, 7. März 2005, 12:00–12:15, TU EB407
Nanomechanical tuning of an optical near-field interaction resonance — •Thomas Taubner1, Fritz Keilmann2, and Rainer Hillenbrand1 — 1Nano-Photonics Group, Max-Planck Institut für Biochemie, 82152 Martinsried — 2Abt. Molekulare Strukturbiologie, Max-Planck Institut für Biochemie, 82152 Martinsried
We use a scattering-type near-field optical microscope (s-SNOM) to experimentally demonstrate the controlled shift of a near-field optical polaritonic resonance. Therefore we study both amplitude and phase of light scattered from a metallic s-SNOM’s tip probing a flat SiC sample, at mid-infrared frequencies where surface phonon polaritons resonantly enhance the tip-sample near-field interaction [1]. Especially, we concentrate on effects of varying the gap width between tip and the sample. We find that a decreasing distance causes a red-shift of the resonance, accompanied by strong optical phase changes [2]. Both effects can be explained by theory that treats the system as a point dipole (tip) interacting with its image dipole (sample), in electrostatic approximation. Tuning the polaritonic resonance of a nanosystem by adjusting nanometric distances could be applied to control confinement and transport of light in nanoassemblies [2].
[1] R. Hillenbrand, T. Taubner and F. Keilmann, Nature 418, 159 (2002)
[2] T.Taubner, F.Keilmann and R. Hillenbrand, Nano Letters 4, 1669 (2004)