Polarization modulation high resolution Fourier transform spectroscopy.
A new polarization modulation Zeeman method combined with high resolution Fourier transform spectroscopy is described. It selectively detects the paramagnetic species produced in a plasma under a constant magnetic field. The polarizing optics is convenient and easily covers wide spectral ranges. NO absorption and N(2)O, NO emission spectra are reported. With a magnetic field of the order of 560 G and a 40-cm long discharge tube, the P and R lines of the 1-0 band of NO around 5 microm are observed up to J = 28.5 whereas the much more intense N(2)O lines are not detected. Unexplained line shapes of the first Q(2) lines of NO are reported. A comparison with a recent frequency modulation Zeeman method coupled with high resolution Fourier transform spectroscopy is given.