COLLISIONAL-DEPHASING AND DOPPLER-BROADENING EFFECTS ON QUANTUM INTERFERENCE IN A VEE ATOMIC SYSTEM

We investigate the effects of collisional dephasing and Doppler broade ning on the quantum beats, narrow resonances, and probe transparency i nduced by quantum interference in a Vee-type atom consisting of an exc ited doublet coupled to a single ground level by the vacuum. We show t hat the amplitudes of the quantum-beat oscillations are greatly reduce d, and the narrow resonances are substantially suppressed and broadene d, for even very small dephasing rates and Doppler broadening. Fluores cence quenching and the previously reported probe transparency can nev er occur in the presence of dephasing collisions and Doppler broadenin g. (C) 1998 Optical Society of America [S0740-3224(98)04907-8].