It is planned to perform a comprehensive and systematic investigations of cooperative cascade superfluorescence in 3- level atomic systems. A synchronously pumped picosecond dye laser working at twice the wave length of the 6S-6D transition in Cs vapor will coherently excite a 6S-6D superposition state which will coherently radiate to the ground state. A resonant optical pumping scheme will allow the polarized two-photon picosecond excitation to invert a small velocity subgroup, lengthening the effective inhomogeneous linewidth to the fluorescence lifetime, so that when superradiance occurs it is delayed from the excitation pulse by a detectable amount. The relative intensities and positions of superradiant burst will be studied as a function of excitation pulse intensity, light traversal time, delay time, and absorption.
