Biexcitonic effect on optical nutation in semiconductor quantum wires

摘要

We have proposed a simplified theoretical model to examine the optical nutation in one-dimensional semiconductor quantum wires. We explored the role of excitons, biexcitons, and the effect of confinement in enhancing transient optical processes in such semiconductor nanostructures. We apply the time dependent perturbation technique to the coherent radiation-semiconductor interaction for a three-level system in the near band gap resonant excitation regime. We have incorporated the relaxation and dephasing mechanisms phenomenologically. The induced polarization is calculated theoretically and the role of biexciton density on the polarization is analyzed. Numerical estimations of refractive and absorptive optical nutation have been made for a GaAs/Al_(x)Ga_(1-x)As quantum wire duly shined by femtosecond pulse Ti: sapphire laser. Our results agree qualitatively with available experimental observations.