Optically detected intersublevel resonance in InAs/GaAs self-assembled quantum dots

We present two-colour pump-probe measurements of the intraband absorption in low growth rate, self-assembled InAs/GaAs quantum dots. The far-infrared resonance observed is unambiguously associated with the dots, and not related to the surrounding material. The results also imply that the interband photoluminescence lines, which appear under high excitation, are from conduction band levels with successively increasing in-plane quantum number. (C) 1999 Elsevier Science B.V. All rights reserved.