Rabi-like oscillations

Fig. 6 Left Echo-detected longitudinal magnetization of Fea as a function of nutation pulse length. Right Absolute-value Fourier Transform, showing contributions due to ESEEM-like effects (sharp peak) and Rabi oscillations broad peak). Adapted from [150]. Used by permission of the PCCP Owner Societies...

The influence of the optically induced local field on Rabi oscillations in a semiconductor quantum dot dominated by phonon-induced damping is theoretically investigated. We find that step-like transitions are inherent to the Rabi oscillations for relatively long pulse durations, while signatures of oscillations are suppressed for weak pulse intensities. 

The pump pulse causes 74% excitation into the A state (between t = —8 and 4 fs). Afterwards the probe pulse train causes transfer of population between the A and B states, and between B and C (and X) states. Transfer of population occurs synchronous with the pulses in the pulse train, causing the step-like appearance seen in Fig. 5.35(a). The pulse train causes ionization simultaneously with population transfer among the neutral states. Time evolution of the ionized population is also seen to be step-like, with change synchronous with the pulses. Thus the electronic excitation and deexcitation seems to be a Rabi oscillation whose timing of transition is well controlled. On the other hand, the relevant nuclear vibrational motion is autonomously evolved in time during the refractory period. 

B state, and 1.8-2.5 A for the C state. In these ranges, electronic transition takes place as though it makes a copy of vibrational wavefunction in the common regions between the relevant electronic states. This is a reflection of the Condon principle. We note that there is counter-intuitive decrease of population in the potential well of the X state when omitting ionization, especially in the panels for Pulse 2 and Pulse 6, indicating there is some deexcitation from the excited electronic states via Rabi-oscillation like coupling with the ion continuum. Thus, complicated transfer, overlapping, and dispersion of the vibrational wavepackets proceed in each electronic state in a stepwise manner. Very fine information in the attosecond time scale is thus folded in the complicated structures and phases of the set of vibrational wavepackets [305]. 

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