We study the interaction of pulsed excitation fields with optically thin atomic ensembles subject to strong cavity-accelerated superradiance. In homogeneously broadened atom-field systems the excitation of superradiant instabilities is seen to lead to a quantization of the total pulse area accrued during excitation and subsequent superradiant decay. In inhomogeneously broadened systems, quasidiscretized area values and pulse area gaps (i.e., forbidden area values) are found. Predicted area discontinuities are demonstrated in cryogenically coherence-stabilized $\mathrm{Tm}{}^{3+}$ ions.

• Received 11 June 2001

DOI:https://doi.org/10.1103/PhysRevLett.87.253602