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IR Correlation Spectroscopy using Microgratings to be Compared with Dispersive IR Spectroscopy #
Author(s) -
Jo ChoongMan,
Choi Eunwoo,
Kim Seong Kyu,
Kim In Cheol,
Park DoHyun,
Kang Young Il
Publication year - 2015
Publication title -
bulletin of the korean chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.237
H-Index - 59
ISSN - 1229-5949
DOI - 10.1002/bkcs.10162
Subject(s) - spectroscopy , infrared spectroscopy , spectral line , absorption spectroscopy , diffraction , analytical chemistry (journal) , chemistry , materials science , optics , physics , organic chemistry , chromatography , quantum mechanics , astronomy
Microgratings that were designed and fabricated to generate IR absorption spectra of SF 6 and NH 3 on diffraction into a specific detection angle were tested by correlation spectroscopy. The micrograting diffraction provides a reference spectrum for a target molecule, and its cross‐correlation with the transmission spectrum of a gas cell is obtained by varying the diffraction angle. As our optical setup can measure the dispersive transmission spectrum and the correlation spectrum under the same conditions, the two kinds of spectra were compared directly in terms of signal‐to‐noise ratio ( SNR ). The SNR ’s of the correlation spectra were a few times lower than those of the dispersed spectra; therefore, the correlation spectroscopy can hardly be placed above the dispersive spectroscopy with respect to the SNR . The merit of the correlation spectroscopy is that a rather small range of modulation wavelength is needed to identify the target. Therefore, the correlation spectroscopy would be more useful for such target molecules whose spectra consist of broad peaks spread throughout a wide wavelength range.