Negligibility of temporal laser wing effects in saturated LIF diagnostics

Abstract.

The temporal influence of a laser pulse on saturated laser-induced fluorescence is investigated by means of numerical solutions of rate equations describing dynamical models of two- and four-level molecular systems. It turns out that temporal wings of the laser become negligible if the saturated fluorescence power from the entire pulse is monitored instead of the total energy obtained from the integrated fluorescence. The negligibility is evaluated relative to the saturation status obtained with temporal sampling of the fluorescence signal as is commonly adopted in the time-resolved technique. The advantages and the limitations of power measurements are discussed with reference to the experimental feasibility of pulse acquisitions for the determination of the flawless saturation degree.