SATURATION BY OPTICAL-PUMPING IN CW LIF SPECTRA OF CAL

Experimental spectra of reactively formed CaI are recorded with the co ntinuous-wave laser-induced fluorescence technique. The spectra are do minated by strong signal saturation. Calculations are performed in whi ch the optical Bloch equations are solved. Under the prevailing experi mental conditions, the saturation is predominated by optical pumping. Rabi oscillations, the usual cause of power broadening, give only a mi nor contribution to the observed signal saturation. A quantitative met hod is proposed to correct the vibrational state population, derived f rom the spectra, for the influence of saturation by optical pumping. S pectrum simulations based on this method show good agreement with the experimentally recorded spectra. Under the condition of strong signal saturation by optical pumping, the signal intensity can be directly re lated to product flux, the quantity of interest in studies of reactivi ties. (C) 1995 Academic Press, Inc.