High-resolution absorption coefficient and refractive index spectra of common pollutant gases at millimeter and THz wavelengths

Dispersive Fourier Transform Spectroscopy (DFTS) provides us with a very precise method of measuring the absorption and refractive index spectra of common pollutant gases. This paper presents the rotational transition lines of Sulfur Dioxide and Carbon Monoxide gas as a function of varying pressure using DFTS for the very first time as a combined study. The relationship between the variation of the pressure and the change in the absorption spectrum is examined and discussed in detail. Sulfur Dioxide and Carbon Monoxide gases are highly toxic, pollutant gases that are major contributors to global pollution and can potentially be used as a chemical threat. The relationship between pressure and rotational transmission lines is discussed in detail in the frequency range of 0.3 THz - 0.9 THz. These findings are crucial in characterizing these gases as well as identifying them in a blind test.