Regensburg 2004 – scientific programme
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O: Oberflächenphysik
O 14: Postersitzung (Adsorption an Oberflächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Phasenübergänge, Rastersondentechniken, Struktur und Dynamik reiner Oberflächen)
O 14.76: Poster
Monday, March 8, 2004, 18:00–21:00, Bereich C
Optical phase effects and resonance shift in scattering-type near-field infrared microscopy — •Thomas Taubner1, Fritz Keilmann1, and Rainer Hillenbrand2 — 1Max-Planck-Institut für Biochemie, Am Klopferspitz 18a, 82152 Martinsried — 2Nano-Photonics Group, Max-Planck-Institut für Biochemie, Am Klopferspitz 18a, 82152 Martinsried
A scattering-type near-field optical microscope (s-SNOM) detects light scattered at the sharp tip of a probing needle and allows imaging with subwavelength resolution, independent of the wavelength used for illumination[1]. We now study amplitude and phase of light scattered from a 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 [2]. A nanometer-scale variation of the gap width between tip and sample causes the optical phase to change dramatically and the resonance to shift. 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. The phase effects and resonance shifts are not restricted to phonon polariton excitation in polar dielectrics like SiC, but should be observable also for resonances related to plasmons and excitons.
[1] T. Taubner, R. Hillenbrand and F. Keilmann, Journal of Microscopy 210, 311 (2003)
[2] R. Hillenbrand, T. Taubner and F. Keilmann, Nature 418, 159 (2002)