Reconstruction of Medium Permittivity Profile Using Terahertz Time-Domain Spectroscopy

The method is developed for solving the inverse problem regarding the reconstruction of the dependence of permittivity on the depth for the non-dispersive, non-absorptive medium based on processing of signals from the terahertz spectrometer. The permittivity profile is reconstructed in two steps. At the first step a pulse function of the medium under study is reconstructed using terahertz spectrometer signals. During the pulse function calculation, the problems of filtering of its low and high frequency noise constituents and interpolation of pulse function at low frequencies are solved. At the second step the medium pulse function is used to reconstruct the permittivity profile with application of the imbedding scattering operator technique. The developed algorithm is tested by means of studying the media with known permittivity profiles.

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