Direct Fabry-Perot effect removal

Abstract

This study indicates that the removal of reflections from T-ray signals can be carried out in the frequency domain without prior knowledge of material parameters or sample thickness. By fitting polynomials to the logarithm and the argument of the sample's transfer function, the Fabry-Pérot reflection term is canceled out, leading to disappearance of the reflections in spatial domain. The method successfully removes the reflections for optically thick samples under the condition of noise or amplitude fluctuations. The application to optically thin samples is possible when the samples are subjected to broadband terahertz measurements. The Fabry-Pérot free signal, when used as input to the parameter estimation method, results in correct material parameters with low variance.