High-Sensitive Fourier-Transform Spectroscopy with Short-Base Multipass Absorption Cells

摘要

A high-sensitive spectrometer operating in the range 20000-9000 cm~(-1) with an absorption sensitivity of 1 × 10~(-8) cm~(-1) and a spectral resolution of 0.05 cm~(-1), based on the Bruker IFS-125M Fourier spectrometer with a short multipass cell, is described. The high sensitivity of the spectrometer was gained through the use of the multipass absorption cell (a base length of 60 cm) with a high transmission (the ratio of the collecting mirror diameter to the base length is 1: 4) and a high intensity light source. The comparison of the recorded spectra with experimental and theoretical water vapor spectra shows that the spectrometer reliably detects absorption lines of natural isotopomers of water. The threshold sensitivity of the spectrometer was found from the signaloise ratio and recorded water lines of minimal intensities.