Novel Method for Extracting Electromagnetic Parameters of Thin Films Based on Dual-Mode Terahertz Time-Domain Spectroscopy Measurements

The article describes a new method for determining the complex dielectric permittivity of films, whose thickness is much smaller than the terahertz (THz) radiation wavelength. This method is based on the simultaneous measurement of THz waveforms reflected by and transmitted through the sample-containing films (dual-mode configuration). We present analytical and numerical solutions of the Maxwell equations, which allow to precisely and easily determine the complex material parameters of the films for transverse electric (TE) and transverse magnetic (TM) polarization cases for the arbitrary incident angle of the THz beam. The proposed method reduces the noise contribution related to laser fluctuation, which improves the precision determination of the dielectric permittivity.