Diode laser emission linewidth determination -: Application to H2O line profile studies in the 5 and 1.4 μm regions

In order to study absorption line profiles using the stabilized diode laser spectrometer of Laboratoire de Physique Moleculaire et Applications (LPMA), a reliable determination of the emission line shape of different diodes laser is needed. In the near infrared region (1.39 and 1.66 mum) we used Distributed Feed Back diode lasers which operate around room temperature and in the middle infrared (5 and 8 mum) we used lead salt diode lasers cooled in a helium closed cycle cryostat or in a liquid nitrogen dewar. Some results obtained in H2O line profile studies in the 1.39 and 5 mum regions are presented as examples demonstrating how absorption line profile measurements can lead to erroneous values of the spectroscopic parameters when the contribution of the diode laser emission line width is neglected. (C) 2002 Elsevier Science B.V. All rights reserved.