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

凝聚态物质中的声子极化激元对它们的电子和光学性质起着核心作用。本文提出将联合收割机散射扫描近场显微镜（s-SNOM）与Rossendorf研究中心的中红外/THz自由电子激光光源（3 ~100 μm）相结合，在光学近场中探测特殊纳米结构的介电共振，其横向分辨率小于10 nm。分离的机械，电子和光学的贡献的信号将通过使用一种新的频率调制的S-SNOM技术以及准外差光学检测的可调谐IR辐射实现。我们的目标是定量地访问声子各向异性和它的张量分量，横向和深入我们的纳米结构。除了铁电和铁电结构，也将研究各种半导体纳米结构，如横向和垂直掺杂结构，自组装量子点，和缺陷沉淀物。

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.