Systematic errors of THz absorption gas spectroscopy due to interference in a multi-pass cell

Abstract

Abstract Multi-pass spectroscopic absorption cells are commonly used in gas spectroscopy to increase the sensitivity of the measurements. The possibility of systematic errors of such measurements was shown in this paper, even for the case when intrinsic transmittance of the cell alters weakly on the line width. The errors could be manifested both in perturbation of the shape of the absorption line and in the sufficient overestimation or underestimation of the absorption strength.