Single-exciton, biexciton, triexciton, and quadraexciton bands were resolved in the microphotoluminescence spectrum of a single CdTe/CdSe core-shell colloidal quantum dot, revealing nearly blinking-free behavior. Multiexcitons were generated by a sequential filling of electronic shells with the increase of a continuous-wave excitation power, and their probability was evaluated under steady-state conditions. A partial carriers' delocalization was determined at the core-shell interface, and an exciton binding energy was estimated by a second-order perturbation theory.

We investigate the propagation of short, intense laser pulses in arrays of coupled silica waveguides, in the anomalous dispersion regime. The nonlinearity induces trapping of the pulse in a single waveguide, over a wide range of input parameters. A sharp transition is observed for single waveguide excitation, from strong diffraction at low powers to strong localization at high powers.

No abstract

We experimentally investigate the behavior of the Fano-like plasmonic resonance lineshape in a simple plasmonic system comprising a subwavelength hole or a particle illuminated by a tightly focused Gaussian beam. We observe that for a small lateral displacement of the scatterer, the k-space distribution of the plasmonic wave exhibits a strong spin-dependent azimuthal variation. We attribute this phenomenon to the sensitive light-plasmon coupling conditions arising due to the specific phase matching requirements. This effect is qualitatively described by a Fano-like interference with a complex coupling factor.

CdTe/CdSe core‐shell colloidal quantum dots (CQDs) were synthesized by a unique colloidal procedure permitting the growth of spherical structures with the highest emission quantum efficiency (∼90%). The CQDs photoluminescence (PL) intensity shows only minor fluctuations (<10%) in time, revealing a blinking suppression in the CQDs, while the PL of a single CQD shows the occurrence of longer lived (ns) multiexcitons, important for the applications of CQDs also in gain devices. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)