Terahertz Transmission Spectra of Condensates of Nitro Compounds

The work is devoted to the experimental and theoretical investigation of terahertz (THz) transmission spectra of hexogen (RDX, cyclotrimethylenetrinitramine) film in the frequency range of the strong characteristic absorption band of RDX at approximately 0.8 THz, measured at various angles of incidence (0°–60°) and polarizations of the probing THz radiation. Experimental THz transmission spectra of the RDX sample were recorded using a THz imaging facility with spectral resolution. For mathematical modeling of the spectra, the characteristic matrix method (transfer matrix method) was employed. It is shown that both the experimental and theoretical THz transmission spectra of the RDX film exhibit a clear manifestation of the hexogen absorption band as a local minimum near the frequency of ~0.8 THz for all studied angles of incidence and polarizations of the probing THz radiation. The results of this work can be used in the development of terahertz systems intended for spectral identification of substances in the condensed phase.