Signatures of Carrier-Wave Rabi Flopping in GaAs

For excitation of the model semiconductor GaAs with optical pulses which are both extremely short (5 fs) and extremely intense (∼1012 W cm-2), we can meet the condition that the Rabi frequency becomes comparable to the band gap frequency -- a highly unusual and previously inaccessible situation. Specifically, in this regime, we observe carrier-wave Rabi flopping, a novel effect of nonlinear optics which has been predicted theoretically and which is related to the failure of the area theorem