Open AccessQuasi-analytical model for scattering infrared near-field microscopy on layered systems
Author(s) -
Benedikt Hauer,
Andreas P. Engelhardt,
Thomas Taubner
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.013173
Subject(s) - optics , materials science , dielectric , scattering , near field scanning optical microscope , infrared , discrete dipole approximation , microscopy , radius , nanoscopic scale , field (mathematics) , optical microscope , optoelectronics , physics , scanning electron microscope , nanotechnology , computer security , mathematics , pure mathematics , computer science
We present a quantitative quasi-analytical model to predict and analyze signals on layered samples measured by infrared scattering-type scanning near-field optical microscopy. Our model predictions are compared to experimental data and to fully retarded calculations based on a point dipole approximation of the tip. The model is used to study the influence of the tip vibration amplitude and of the tip radius on the near-field contrasts of samples with particularly small variations in the layer thickness. Additionally the influence of a dielectric capping layer on the tip-substrate coupling is analyzed. When inversely applied, our calculation opens the possibility to extract the local layer thickness of thin films or the dielectric functions that allow one to draw conclusions on the material composition, conductivity or crystal structure on the nanoscale.