We report cavity ringdown spectra of lithium vapour generated in the heat-p
ipe oven. Evaluation of ringdown decay curves in early and late time window
s gives the change of absorption peak values as well as in the line shape p
rofiles. Pronounced dips in the line center occur depending on molecular de
nsities, injected laser pulse energies and chosen time window. (C) 2000 Els
evier Science B.V. All rights reserved.