The general problem of level crossing and optical double resonance line shapes is studied under different conditions of pulsed excitation. The theoretical effects of variable pulse shape and duration, of long and short observation periods, and the effects of positive and negative delay between the end of the pulse and the beginning of observation of the emitted fluorescence are investigated by means of a simple classical formulation. Agreement is obtained with line-shape expressions previously derived for more restricted assumptions. It is also shown that under appropriate conditions, pulse-excitation line shapes yield independent information on the mean life τ and <i>g</i> factor of the decaying state that has not been fully exploited in pulsed experiments carried out to date.
ROBERT C. HILBORN and ROBERT L. DEZAFRA, "Effects of Pulsed Excitation on Level Crossing and Optical Double Resonance Line Shapes," J. Opt. Soc. Am. 62, 1492-1497 (1972)