Fast analysis of gases in the submillimeter∕terahertz with “absolute” specificity

Abstract

A submillimeter∕terahertz point detector for gas monitoring and quantification is described. It is based upon the fast ( ∼ 15 GHz ∕ s ) sweeping of high spectral purity ( < 1 ∕ 10 7 ) , high brightness ( ∼ 10 14 K ) microwave sources and a scanning electronic reference for frequency measurement. This approach can quantify the complex rotational spectrum of gases at a rate of ∼ 10 5 spectral resolution elements∕second at high signal to noise. This resolution and the uniqueness of Doppler limited rotational spectra provide “absolute” specificity and “zero” false alarm rates even in complex mixtures. Moreover, the small size, low power consumption, and the potential of very low cost make this approach attractive for a number of important applications.