title: Femtosecond laser Fourier transform absorption spectroscopy.
abstract: A femtosecond mode-locked laser is used for what is believed to be the first time as a broadband infrared source for high-resolution Fourier transform absorption spectroscopy. A demonstration is made with a Cr(4+):YAG laser. The entire nu(1)+nu(3) vibration-rotation band region of acetylene, observed after passing through a single-pass 80-cm-long cell, is simultaneously recorded between 1480 and 1600 nm, in 7.9 s with a signal-to-noise ratio equal to 1000. Two hot bands of the most abundant acetylene isotopologue and the nu(1)+nu(3) band of the (13)C(12)CH(2) are also present. Replacement of the usual conventional tungsten lamp by the bright laser source reduces by about a factor of 150 the recording time needed to get similar results. The noise equivalent absorption coefficient at 1 s averaging is equal to 7x10(-7) cm(-1)Hz(-1/2) per spectral element.
authors.affiliation: Laboratoire de Photophysique Moléculaire, CNRS, Université de Paris-Sud, Orsay, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Mandon
authors.forename: Guy
authors.initials: G
authors.lastname: Guelachvili
authors.forename: Nathalie
authors.initials: N
authors.lastname: Picqué
authors.forename: Frédéric
authors.initials: F
authors.lastname: Druon
authors.forename: Patrick
authors.initials: P
authors.lastname: Georges