Abstract
The transient fluorescent spectrum of a non-dissipative single 2-level atom driven by a resonant rectangular pulse is investigated analytically and computationally with the Haar wavelet window function. The shift parameter (k) of the mother wavelet function induces periodic effect. For weak pulse, a central dip structure -characteristic of the window transmission lines-occurs in the spectrum. With initial atomic coherent state and for strong pulse and large (k), interference of the strong Rabi oscillations induces asymmetrical dense 'ringing' around the two Rabi side bands of the spectrum.