Optically induced excitation density flops in semiconductors

The optically induced excitation density in a semiconductor multiple quantum well is experimentally observed to go through a maximum at sufficiently high excitation intensity. This is achieved by using the interaction of two copropagating ultrafast optical pulses to extract the temporal dependence of the optically induced polarization, which is proportional to the temporal derivative of the excitation density. Solutions to the Maxwell semiconductor Bloch equations show that the observations are a manifestation of Rabi flopping in semiconductors. The results confirm the presence of many‐body modifications to the Rabi flopping for the excitation conditions used in the experiment.