Coherent response of individual weakly confined exciton-biexciton systems

Jacek Kasprzak (1) , Langbein Wolfgang (2)

1 NEEL - NPSC - Nanophysique et Semiconducteurs
2 School of Physics and Astronomy [Cardiff]

We investigate the coherent optical response of individual localized exciton-biexciton (X-XX) systems formed at interface fluctuations of a growth-interrupted GaAs/AlAs quantum well. We apply heterodyne spectral interferometry to perform two-dimensional four-wave mixing (FWM) spectroscopy. We retrieve the binding energy of bound and unbound XXs, as well as characterize the system in terms of biexciton-exciton dipole moment ratio and mutual FWM phase. Polarization selection rules of the FWM are determined. FWM hyperspectral imaging and autocorrelation analysis reveal the expected spatial colocalization of XXs with respect to their Xs. A value for the biexciton renormalization in a coherently coupled pair of Xs is retrieved. Our study gives insight into the coherent optical properties of an exciton-biexciton system with a confinement energy comparable to the biexciton binding energy.

Mots clés: nonlinear optics; four-wave mixing; optical nonlinearities of condensed matter; spectroscopy; heterodyne

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Jacek Kasprzak, Langbein Wolfgang. Coherent response of individual weakly confined exciton-biexciton systems. Journal of the Optical Society of America B, 2012, 29 (7), pp.1766. ⟨10.1364/JOSAB.29.001766⟩. ⟨hal-00712079⟩