Fast analysis of gases in the submillimeter/terahertz with absolute specificity

A submillimeter/terahertz point detector for gas monitoring and quantification is described. It is based upon the fast (similar to 15 GHz/s) sweeping of high spectral purity (<1/10(7)), high brightness (similar to 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 similar to 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. (C) 2005 American Institute of Physics.