Principal limitation of standard THz time-domain spectroscopy method of the detection and identification of substance and way of its overcoming

Abstract

We demonstrate principal limitations of standard Time Domain Spectroscopy based on a broadband THz pulse for the detection and identification of substance using paper napkins as a sample. To avoid these limitations we propose a new high effective algorithm for this purpose. We demonstrate its applicability in realistic and simulated situation for various substances under consideration. The interaction of a THz pulse with a disordered layered structure was simulated in order to show the influence of the disordered layers on the spectral characteristics of the transmitted and reflected signals. Spectral characteristics of these signals were analyzed in a direct comparison with the spectrum of the incident pulse as well as by means of Spectral Dynamics Analysis method and integral correlation criteria. The efficiency of the detection and identification method, based on integral correlation and likeness criteria, is confirmed on the basis of computer simulation. To demonstrate the possibilities of the integral correlation criteria in real experiment, they were applied for the identification of explosive HMX in the reflection mode.