Rabi frequency

The Rabi frequency is the frequency of oscillation for a given atomic transition in a given light field. It also gives the measure of the fluctuation of population between the levels. It is associated with the strength of the coupling between the light and the atomic transition. Rabi flopping between the levels of a 2-level system illuminated with resonant light, will occur at the Rabi frequency. The Rabi frequency is a semiclassical concept as it is based on a quantum atomic transition and a classical light field.