PRECISION LIMITATIONS OF DIODE-LASER SPECTROSCOPY - SPECTRAL LINESHAPE MEASUREMENTS AND BASE-LINE CONSIDERATIONS

The paper deals with the precision limitations resulting from baseline (total transmission level) determination error when using diode laser spectroscopy techniques to measure spectral lineshapes. Analytical ex pressions have been derived to describe the distortions of analyzed sp ectral line parameters including the intensity as well as Lorentzian a nd Gaussian broadening. The expressions were confirmed by computer sim ulation and by processing of experimental high-resolution spectra. Our analysis shows that conventional methods limit the accuracy to approx imately 1% when measuring line parameters. This accuracy level is not adequate to solve some fundamental and applied problems. Thus, an appr oach is proposed that ensures significantly improved precision. The ra tio of intensities of spectral lines has been measured with an accurac y on the order of 0.1-0.3%. (C) 1995 Academic Press, Inc.