Infrared scattering near-field optical microscopy near dielectric (polaritonic) resonances using a free-electron laser

• Applicants: Professor Dr. Lukas M. Eng; Professor Dr. Manfred Helm
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2007 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 40157543

Phonon-polaritons in condensed matter play a central role for their electronic and optical properties. Here we propose to combine scattering scanning near-field microscopy (s-SNOM) with the mid-infrared/THz free-electron laser light source (3- ~100 μm) at the Forschungszentrum Rossendorf in order to probe dielectric resonances of spezial nanostructures in the optical near-field with < ~10 nm lateral resolution. A separation of mechanical, electronic, and optical contributions to the signal will be achieved by using a novel frequency-modulated s-SNOM technique as well as quasi-heterodyne optical detection of the tunable IR radiation. It is our goal to quantitatively access the phonon anisotropy and its tensorial components, both laterally and into the depth of our nanostructures. Apart from ferroelectric and ferroic structures, also various semiconductor nanostructures will be investigated, such as laterally and vertically doped structures, self-assembled quantum dots, and defect precipitates.

• DFG Programme: Research Grants