Effect of polarization state of light on magnetoabsorption and optical nutation in GaAs/AlGaAs quantum well structures

Rigorous dipole selection rules are derived for an interacting electron–hole system in a multiband magneto-active GaAs/AlGaAs semiconductor quantum well (QW). The valence band structure is modelled using an 8×8 Luttinger Hamiltonian under the axial approximation. For three different polarization states of input pulse radiation i.e. linearly (σzσz)-, right circularly (σ+σ+)- and left circularly (σ−σ−)-polarized, we have studied the absorption characteristics of a GaAs/AlGaAs QW under the influence of a magnetic field applied perpendicular to the growth direction. A strong blue shift of the absorption peaks is observed with increasing magnetic field. Also, spin splitting of the absorption peaks is seen for the case of linearly polarized input radiation. Numerical estimation of optical nutation has been made for GaAs/AlGaAs under the influence of strong magnetic field and it is observed that nutating signal frequency enhances with increasing magnetic field.