Windowing of THz time-domain spectroscopy signals: A study based on lactose

•We present a detailed study of the properties of the signal windowing for THz time-domain signals.•We quantify the influence of an extensive collection of windowing functions.•A Force-Exp window (usually applied to impact/sound analysis) is also included due to the impulsive character of these signals.

Time-domain spectroscopy has established itself as a reference method for determining material parameters in the terahertz spectral range. This procedure requires the processing of the measured time-domain signals in order to estimate the spectral data. In this work, we present a thorough study of the properties of the signal windowing, a step previous to the parameter extraction algorithm, that permits to improve the accuracy of the results. Lactose has been used as sample material in the study.