title: Impact of atmospheric clutter on Doppler-limited gas sensors in the submillimeter/terahertz.
abstract: It is well known that clutter (spectral interference) from atmospheric constituents can be a severe limit for spectroscopic point sensors, especially where high sensitivity and specificity are required. In this paper, we will show for submillimeter/terahertz (SMM/THz) sensors that use cw electronic techniques the clutter limit for the detection of common target gases with absolute specificity (probability of false alarm ≪ 10⁻¹⁰) is in the ppt (1 part in 10¹²) range or lower. This is because the most abundant atmospheric gases are either transparent to SMM/THz radiation (e.g., CO₂) or have spectra that are very sparse relative to the 10⁵ Doppler-limited resolution elements available (e.g., H₂O). Moreover, the low clutter limit demonstrated for cw electronic systems in the SMM/THz is independent of system size and complexity.
authors.affiliation: Department of Physics, Wright State University, 3640 Colonel Glenn Highway, Dayton, Ohio 45435, USA.
authors.forename: Ivan R
authors.initials: IR
authors.lastname: Medvedev
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Neese
authors.forename: Grant M
authors.initials: GM
authors.lastname: Plummer
authors.forename: Frank C
authors.initials: FC
authors.lastname: De Lucia