Theory of optical nutation in direct-gap semiconductors due toultrashort resonant laser irradiation

An analytical investigation of optical nutation in direct-gap semiconductors such as GaAs, InSb, and Hg_1-xCd_xTe based on the time-dependent perturbation technique is discussed. The crystals are considered to be irradiated by short pulsed moderate power near-resonant lasers producing significant density of optically-induced free electron-hole pairs. Incoherent dephasing mechanisms have been introduced phenomenologically into the coherent radiation-semiconductor interaction model. The theory, on application to the case of a specific crystal such as Hg_1-xCd_xTe with x=0.18 irradiated by a pulsed 10.6 μm CO₂ laser, manifests distinctly the occurrence of ringing behavior in the transmitted intensity, transient dispersion, and absorption even in the absence of any theoretical averaging or the consideration of the effective density of states