COOPERATIVE SUPERFLUORESCENCE AND TIME-DELAYED 2ND-HARMONIC GENERATION

A 10 ps transform limited optical pump pulse two-photon-resonant with the 6 S-1/2 - 6 D-3/2 442 nm transition in Cs vapor generates a cohere nt state superposition which, after a delay exceeding the pulse width, gives rise to second harmonic emission (when a transverse magnetic fi eld is present) and superfluorescence (SF) directed against the pump o n the upper 6 D-3/2 - 6 P-1/2 transition, followed by cooperative SF a long the pump simultaneously on both the upper and lower 6 P-1/2 - 6 S -1/2 transitions, followed in turn by SF against the pump on the lower transition, Phase locked quantum beats associated with the 1.17 GHz h yperfine splitting of the 6 P-1/2 appear on all SF emissions.