Applied Physics B

, Volume 59, Issue 3, pp 333–343

Ultrahigh-resolution saturation spectroscopy using slow molecules in an external cell

  • Ch. Chardonnet
  • F. Guernet
  • G. Charton
  • Ch. J. Bordé
Regular Paper

DOI: 10.1007/BF01081402

Cite this article as:
Chardonnet, C., Guernet, F., Charton, G. et al. Appl. Phys. B (1994) 59: 333. doi:10.1007/BF01081402

Abstract

We present the narrowest molecular lines so far recorded in the 10 µm spectral region. A linewidth of 80 Hz (HWHM) has been obtained for theP(39)A13(−) line of OsO4, by selecting slow molecules (Teff=0.6 K) in saturation spectroscopy at low laser fields (30 nW) and low pressures (2 × 10−6 Torr). In these conditions, the contribution of the fast molecules is greatly reduced because of the finite size of the beam. This method, applied previously to methane at 3.39 µm, is used for the first time in an external cell and improves by a factor 8 the best resolution of our spectrometer. Heterodyne detection and double frequency modulation have been necessary to extract a signal at a contrast of only 10−6. The physical ideas concerning this regime are described and a detailed analysis of the line shape is given.

PACS

33.80-b 42.62.Fi 

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • Ch. Chardonnet
    • 1
  • F. Guernet
    • 1
  • G. Charton
    • 1
  • Ch. J. Bordé
    • 1
  1. 1.Laboratoire de Physique des Lasers, URA du CNRS No. 282Université Paris-NordVilletaneuseFrance

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