Exciton susceptibility of semiconductors at high laser-excitation levels

The hysteresis behavior of the real and imaginary parts of the susceptibility of a semiconductor in the exciton region of the spectrum is investigated with consideration of the exciton-phonon and elastic exciton-exciton interactions in the pump-probe regime as a function of the intensity and frequency of the strong laser pulse and the frequency of the probe pulse. The conditions for the appearance of suppression of the damping and amplification of the probe pulse are determined. Abrupt red and blue shifts of the spectral position of the exciton absorption band as a function of the pump pulse intensity are predicted. Fiz. Tverd. Tela (St. Petersburg) 40, 934–935 (May 1998)