2023/05/26 by Dario Siebenkotten, Siebenkotten, Dario, B. Kaestner +5
Engineering · Materials Science · #FOS: Physical sciences #Near-Field Optical Microscopy #Optics (physics.optics) #Photonic and Optical Devices #Quantum Dots Synthesis And Properties
paper · pdf · doi:10.48550/arxiv.2305.17031
openalex publication_date 2023/05/26 · openalex created_date 2023/05/30 · openalex updated_date 2026/07/28
Scattering-type scanning near-field optical microscopy (s-SNOM) enables sub-diffraction spectroscopy, featuring high sensitivity to small spatial permittivity variations of the sample surface. However, due to the near-field probe-sample interaction, the quantitative extraction of the complex permittivity leads to a computationally demanding inverse problem, requiring further approximation of the system to an invertible model. Black-box calibration methods, similar to those applied to microwave vector network analysers, allow the extraction of the permittivity without detailed electromagnetic modelling of the probe-sample interaction. These methods, however, are typically designed for stationary setups. In contrast, the distance between the sample and the probe tip of the s-SNOM is slowly modulated, which is required for the lock-in detection used to extract the near-field interaction buried in the far-field background. Here we propose an improved calibration method that explicitly takes probe tapping into account. We validate our method for an s-SNOM operating in a mid-infrared spectral range by applying it to measurements of silicon microstructures of different but well characterised doping.