Applied Physics Letters
Two-photon spectral hole burning spectroscopy of InAs/GaAs quantum dots
Thomas Moldaschl, Wolfgang Parz, Thomas G. Muller, Sebastian Golka, G. Strasser, K. Unterrainer
Abstract
Femtosecond spectral hole burning experiments were performed on InAs/GaAs quantum dots to investigate the influence of high excitation intensities. The observation of additional spectral holes, as well as distinct absorption line broadening are both attributed to two-photon absorption processes. These spectral holes can be unambiguously assigned to degenerate two-photon biexciton creation, whereas the absorption line broadening is a direct result of Coulomb renormalization, initiated by carriers created through two-photon absorption in the surrounding GaAs crystal matrix and the InAs wetting layer.