Unravelling the mechanisms of interference between overlapping resonances

The enhancement of the resonance lifetime that occurs upon interference of two overlapping resonances excited coherently by two pulses with delayed time has been investigated as a function of the pulse temporal width and the delay time between the pulses. A general law predicting quantitatively the optimal delay time that maximizes the lifetime enhancement of the two resonances has been established in terms of the pulse width and of the lifetimes of both resonances when they are excited isolatedly. The specific form of the law and all the results found can be closely related to the characteristic features of the mechanism of interference between the overlapping resonances, providing a detailed understanding on how the mechanism operates. The proposed law is envisioned as a useful tool to design experimental strategies to control the resonance lifetime.