Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 27: Poster Session I (Methods: Scanning probe techniques; Methods: Atomic and electronic structure; Methods: Molecular simulations and statistical mechanics; Oxides and Insulators: Clean surfaces; Oxides and Insulators: Adsorption; Oxides and Insulators: Epitaxy and growth; Semiconductor substrates: Clean surfaces; Semiconductor substrates: Epitaxy and growth; Semiconductor substrates: Adsorption; Nano- optics of metallic and semiconducting nanostructures; Electronic structure; Methods: Electronic structure theory; Methods: other (experimental); Methods: other (theory); Solutions on surfaces; Epitaxial Graphene; Surface oder interface magnetism; Phase transitions; Time-resolved spectroscopies)
O 27.25: Poster
Dienstag, 24. März 2009, 18:30–21:00, P2
Infrared antennas for near-field microscopy and enhanced near-field spectroscopy — •Thomas Taubner1,2, Mark Brongersma2, and Jon Schuller2 — 1I. Physikalisches Institut, RWTH Aachen, Germany — 2Department of Material Science, Stanford University, USA
Scattering-type near-field optical microscopy (s-SNOM) relies on the scattering of light at a sharp metallic tip to obtain images with a resolution independent of the wavelength. The use of infrared light enables the acquisition of spectroscopic information on a samples chemical, structural and electronic properties at nanoscale resolution. Currently, the main limitation of this technique comprises of the low signals that demand tunable laser sources and restrict the spectral range of operation.
We present new concepts to increase the sensitivity of IR near-field spectroscopy in order to apply s-SNOM over a broader spectral range in the mid-IR. We suggest to employ resonantly enhanced near-fields of metallic nanostrutures: The optical properties of materials of such structures can be tuned by changing their size to create optical antennas that concentrate light into tiny, subwavelength volumes. Specifically, we investigate the antenna properties of modified, metal-coated AFM tips in order to enable high-resolution near-field microscopy with increased sensitivity. We also show that the near-field probing process can be enhanced by suitable substrates, increasing both signals and contrasts in infrared s-SNOM when probing thin sample layers.