Berlin 2012 – wissenschaftliches Programm

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MI: Fachverband Mikrosonden

MI 3: Scanning probe microscopy

MI 3.1: Vortrag

Montag, 26. März 2012, 12:45–13:00, EMH 225

Chemical nano-imaging of thin surface layers by combining AFM with tip-localized infrared spectroscopy — Sergiu Amarie and •Fritz Keilmann — MPI für Quantenoptik, Garching

We have extended the scattering near-field microscope (s-SNOM) that returns an optical image together with topography, both at <20 nm resolution, by operating with broadband infrared illumination. Thus a continuous infrared spectrum from 4 to 15 micron wavelength can be recorded at each scanned pixel. As this covers the "molecular fingerprint" region one can determine the local chemical composition. The probing depth is about equal to the spatial resolution, of the order of the tip radius of typically 20 nm. Our new method should find many applications requiring a quantitative material analysis at the nanoscale, be it in general analytical chemistry, nanofabrication, mineralogy or condensed matter physics.

Results of imaging hard biological matter will be presented, where phosphate and carbonate nanocrystals evoke especially bright contrasts due to infrared phonon resonance, and where new insights into biomineral growth and decay mechanisms of biological and even medical interest can be expected.