Reference-free self-calibrating tip-based scattering-type THz near-field microscopy

In this work, we present a quantitative analysis model based on reference-free self-calibration to analyze scattered fields and approach curves dielectric substrate for terahertz scattering-type scanning near-field optical microscopy. The results of our are compared with experimentally measured data fully numerical line dipole image method quasi-electrostatic approximation. is used extract the effective radius tip relative permittivity silicon scattering signal. Au substrates show good agreement calculated curves, refractive index precisely determined be 3.42. For tip-based THz microscope, proposed allows extraction probe functions, thereby enabling conclusive measurements geometric parameters constants.