Narrow-band near-field nanoscopy in the spectral range from 1.3 to 8.5 THz
Abstract
Nano-spectroscopy in the terahertz frequency range remains challenging despite recent technological progress in developing both THz emitter sources and near-field optical microscopy (SNOM). Here, we combine scattering-type SNOM with a free-electron laser light source, to tune into the 1.3-8.5 THz range. A significant portion of this range, namely, the frequencies above ∼3 THz, is not covered by previously reported near-field microscopy systems. However, it constitutes an indispensable regime where many elementary processes in solids including collective lattice excitations, charge, and spin transport occur. Our approach of nano-spectroscopy and nano-imaging provides a versatile analysis of nanostructures as small as 50 nm, hence beating the optical diffraction limit by λ/4600.
- Publication:
-
Applied Physics Letters
- Pub Date:
- March 2016
- DOI:
- 10.1063/1.4943793
- Bibcode:
- 2016ApPhL.108k3102K