Features of the interaction of ultrashort laser pulses with a thin semiconductor film caused by the generation of excitons and biexcitons

Nonstationary transmission (reflection) of two time-separated ultrashort laser pulses by thin semiconductor films is studied. Photons of one of these pulses generate biexcitons in the films due to two-photon absorption from the crystal ground state, while photons of the other pulse induce an optical exciton – biexciton conversion. Several basically new effects in nonstationary light transmission (reflection) are found and interpreted.