Two-photon absorption and third-order nonlinearities in GaAs quantum dots

Third-order optical nonlinearities of GaAs quantum dots are investigated theoretically. Two quantum confinement regimes are analyzed, and large optical nonlinearities are predicted for sufficiently narrow linewidths. The appearance of an induced (two-photon) absorption resonance is predicted energetically above the exciton resonance for quantum-dot radii, which are between the electron and hole Bohr radii.