A method for removing etalon oscillations from THz time-domain spectra

We present a simple algorithm for removing or reducing spurious oscillations in the THz spectra which result from secondary reflection peaks in samples or optical elements. The algorithm utilizes the fact that a THz time-domain trace containing secondary peaks can be represented as a convolution of the primary peak and two or more delta functions. The algorithm is applicable for samples which are sufficiently thick that the reflection peak does not overlap with the primary peak, and that do not have strong absorption or dispersion.