Suppression of spectral interferences due to water-vapor rotational transitions in terahertz time-domain spectroscopy.
Absorption lines of atmospheric water vapor are commonly present in terahertz spectra measured in ambient air. These spectral interferences are caused by the rotational transitions of water molecules. In this study, we develop an effective method for suppression of the water-vapor effects by modeling the absorption lines using Lorentzian line shape and spectroscopic parameters extracted from the HITRAN database and then subtracting them iteratively in the frequency domain. The free-space terahertz pulse and the absorbance spectrum of an explosive material are restored successfully in the experimental verification.
Department of Engineering Physics, Tsinghua University, Beijing, China.
Yingxin
Y
Wang
Ziran
Z
Zhao
Zhiqiang
Z
Chen
Yan
Y
Zhang
Li
L
Zhang
Kejun
K
Kang