Search

Two-photon absorption (TPA) in a semiconducting quantum well (QW) is investigated theoretically in the presence of the electric field. Numerical results show that the TPA depends strongly on the relative orientations of the electric field, the direction of optical polarization, and the direction of carrier confinement in the QW. The TPA is finite at photon energy below the threshold energy where the TPA would vanish in the absence of the electric field for any case. The TPA is large when the electric field is along the direction of carrier confinement in the QW. Moreover, when the electric field is in the plane of the QW, the difference Δα between the TPAs in a finite electric field and in zero field at the threshold energy increases almost linearly with increasing the electric field. In addition, it is also found that, in all cases, the TPA is less in the QW than that in the bulk.

Previous calculations have shown a transition between two dimensional and three dimensional behavior of excitons confined in a semiconducting quantum well structure as a function of electric field. We here present calculations of the exciton binding energy as a function of electric field using a two parameter variational wave function of the form used in the absence of the electric field by Matsuura and Shinozuka. Our calculations were performed using a finite potential barrier model for the confinement of the exciton in the quantum well. The results of our calculations confirm the validity of the conclusion that the variational exciton wave function goes from being of a purely 2D hydrogenic type at small well widths and/or low electric fields to a 3D hydrogenic type in wide wells and/or high electric fields. Copyright 1995, 1999 Academic Press