Near-field imaging of one-dimensional excitons delocalized over mesoscopicdistances - art. no. 121313

Near-field optical spectroscopy is used to investigate the effects of disor der in the optical processes in semiconductor quantum wires. We observe pho toluminescence emissions from extended, delocalized excitons at low tempera tures (5 K) and low excitation densities. Combining high spectral and spati al resolution, we isolate homogeneous emission lines from excitons delocali zed over distances up to 600 nm in the fundamental state. The energies of t he emissions are consistent with different quantum spatial confinements alo ng the win axis. Unlike the photoluminescence originating from localized ex citons, these emission lines show a high degree of polarization along the a xis of the wire.