Abstract

Intracavity laser spectroscopy (ILS) with multimode broadband dye lasers is studied relative to its capability to accurately reveal absorption lineshapes of gas samples placed within the laser cavity. The extended cavity dye laser is operated in chopped mode to maintain the broadband output (Fig. 1). The output of the ILS laser is fed simultaneously to both medium and high resolution spectrographs (resolving powers of 100,000 and 800,000 respectively) via an optical fiber. Broadband tuning of the ILS laser is accomplished by rotating an intracavity pellicle, which acts as a thin etalon. A cryogenically cooled absorption cell is placed within the laser cavity. The conditions necessary to avoid both lineshape distortion (by nonlinear processes) and spectral contamination (by parasitic fringe structures) have been established. Procedures have been developed for the calibration of high resolution spectra and for the analysis of highly congested spectra. A scanning technique has been developed to measure absorption coefficients over broad spectral ranges at low to medium resolutions.

© 1992 Optical Society of America