Abstract : The main issue of this work is the experimental development of an intracavity spectroscopic method aims at enhanced the sensibility of Laser Induced Fluorescence (LIF) couplet to High Resolution Fourier Transform Spectroscopy (LIF-FTS). This enhancement is achieved by an external build-up cavity coupled to a Fourier transform spectrometer. The molecular source is inserted in the cavity which stock the energy of a single mode CW dye laser. The build-up conditions are maintained by an opto-electronic servo-loop.
The intracavity power enhancement allows the observation of invisble molecular quantum level in standard LIF experiments. This technique (ICLIF) is validate by the study of an astrophysical radical : NiH, produced in a new changeable hollow cathode source developed during this work.