Rabi-flopping frequency

With increasing RF intensity, however, saturation broadening is observed (Vol. 1, Sect. 3.6) and the double-resonance signal may even exhibit a minimum at the center frequency 0)23 (Fig. 5.9). This can readily be understood from the semiclassical model of Vol. 1, Sect. 2.7 for large RF field amplitudes Erf the Rabi flopping frequency Vol. 1, (2.90)... 

If the laser pulse applied to the sample molecules is sufficiently long and intense, a molecule (represented by a two-level system) will be driven back and forth between the two levels at the Rabi flopping frequency (Vol. 1, (2.96)). The time-dependent probability amplitudes ai (t) and 02 (0 are now periodic functions of time and we have the situation depicted in Vol. 1, Fig. 2.23. Since the laser beam is alternately absorbed (induced absorption E E2) and amplified (induced emission 2 i). the intensity of the transmitted beam displays an oscillation. Because... 

Fig.2.20. Population probability b t) of the levels Eh altering with the Rabi flopping frequency due to the interaction with a strong field. The resonant case is shown without damping and with damping due to decay channels into other levels. The decaying curve represents the factor cxp[—(yab/2)/J...

This is a damped oscillation (Fig.2.20) with the damping constant yah = iYa + Yb)/X the Rabi flopping frequency... 

Rabi flopping frequency Q, sidebands are generated at a>o that have the homogeneous linewidth ys. The superposition of these sidebands (Fig. 3.25) gives a line profile that depends on the ratio 2/ys of the Rabi flopping frequency 2 and the saturated linewidth ys. For a sufficiently strong pump wave (f2 > ys), the separation of the sidebands becomes larger than their width and a dip appears at the center coq. 

The general Rabi flopping frequency 12 gives the frequency of population oscillation in a two-level system in an electromagnetic field with amplitude Eq. 

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