For excitation of the model semiconductor GaAs with optical pulses which ar
e both extremely short (5 fs) and extremely intense (approximate to 10(12)
Wcm(-2)), we can meet the condition that the Rabi frequency becomes compara
ble to the band gap frequency-a highly unusual and previously inaccessible
situation. Specifically, in this regime, we observe carrier-wave Rabi flopp
ing, a novel effect of nonlinear optics which has been predicted theoretica
lly and which is related to the failure of the area theorem.