THz pulse duration influence on high-energy level excitation due to cascade mechanism

We study influence of an incident broadband THz pulse duration on the spectral features of a signal transmitted through/reflected from a substance covered by a disordered structure by means of computer simulation. It is well-known that under real conditions, the results of a standard THz TDS undergo various factors. For example, a substance under investigation can be put into a bulk medium with ordinary properties. This often results in the distortion of the reflected/transmitted pulse spectra and hence, one may reveal additional absorption frequencies which can be thought as belonging to a dangerous substance. An issue from this situation may be a substance emission spectrum using. As we showed the emission frequencies appear due to the cascade mechanism of higher energy level excitation. In this paper we study the incident THz pulse duration influence on the emission frequencies manifestation.