On the diagnostics of semiconductors upon two-photon excitation of biexcitons

A version of the one-photon probing of optical properties of semiconductors is presented under conditions when a high-power pump pulse excites biexcitons from the ground state of a crystal due to two-photon absorption. The existence of a Lorentzian absorption peak is predicted and the quasi-polariton dispersion law is found in the region where a real energy level is absent. The temporal evolution of the absorption band under the action of ultrashort pulses is studied.