Superradiant emission dynamics of an optically thin material sample in a short-decay-time optical cavity

We report observations of optical superradiant emission and the atomic evol ution it drives under conditions closely approximating those originally env isioned in the classic work of Dicke [Phys. Rev. 93, 99 (1954)]. Our experi ment involves an optically thin solid sample in a short-lifetime optical ca vity whose homogeneous coherence is cryogenically stabilized. Pulsed cohere nt excitation initiates superradiant emission which subsequently drives the sample to higher or lower states of coherence. Suppression of dephasing vi a cryogenics and propagation effects through use of an optically thin sampl e and cavity provides one of the dearest and cleanest examples of Dicke sup erradiance yet reported.