STUDY OF THE DOPPLER-FREE OPTICAL-OPTICAL TRIPLE-RESONANCE (DF-OOTR) SPECTROSCOPY AND ITS LINESHAPES

The Doppler-free optical-optical triple-resonance(DF-OOTR) spectroscop y and its lineshapes have been studied in detail theoretically and exp erimentally. The Line center, linewidth and lineshape of an isolated D F-OOTR spectra compenent have been derived by using density matrix mot ion equation describing the interaction of a three-level system with t hree optical fields. The variations of the lineshape symmetry, the rel ative position and the strength of the Doppler-free Lorentzian dip to its background are comparable to the experimental traces varying with the relative intensities of the two mutual-saturating probe laser beam s, as well as with the detuning of the first pumping laser from the in termediate level. The DF-OOTR technique shows a distinguished advantag e especially in the labeling of the transitions and in the determinati on of absolute position of the upper level affected by perturbation sh ift, as these happened often in the dense molecular highly excited sta tes.