The quantum confined Stark effect is observed for quantum dots (QD's) exposed to randomly fluctuating electric fields in epitaxial structures. These fields, attributed to charges localized at defects in the vicinity of the QD's, lead to a jitter in the emission energies of individual QD's. This jitter has typical frequencies of below about 1 Hz and is characteristic for each QD thus providing a unique means to unambiguously identify the emission spectra of single QD's. Up to eight lines are identified for individual QD's and attributed to excitonic, biexcitonic, and LO-phonon-assisted transitions. The intensity of the LO-phonon replica is surprisingly large corresponding to Huang-Rhys factors of about one

We report on an experimental and numerical study of chaotic behavior in random lasers. The complex emission spectra from a disordered amplifying material with static disorder are investigated in a configuration with controlled, stable experimental conditions. It is found that, upon repeated identical excitation, the emission spectra are distinct and uncorrelated. This behavior can be understood in terms of strongly coupled modes that are triggered by spontaneous emission, and is expected to play an important role in most pulsed random lasers.

The authors present a technique that allows to modify the local characteristics of two-dimensional photonic crystals by controlled microinfiltration of liquids. They demonstrate experimentally that by addressing and infiltrating each pore with a simple liquid, e.g., water, it is possible to write pixel by pixel optical devices of any geometry and shape. Calculations confirm that the obtained structures indeed constitute the desired resonators and waveguide structures.

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We study the localization and addressability of ultracold atoms in a combined parabolic and periodic potential. Such a potential supports the existence of localized stationary states and we show that applying a radio frequency field allows us to selectively address atoms in these states. This method is used to measure the energy and momentum distribution of the atoms in the localized states. We also discuss possible extensions of this scheme to address and manipulate atoms in single lattice sites.

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Single InGaAs quantum wires were fabricated by low pressure metal organic chemical vapor deposition on V-grooved InP substrates. For substrate patterning a new wet chemical etching process that leads to high quality V-grooves with {111}A facets was used. The growth parameters of the InP buffer layer have a strong impact on the quantum wire formation. Scanning electron microscopy, photoluminescence, and spatially resolved cathodoluminescence experiments have been performed to characterize the structures. The crescent shaped InGaAs quantum wires have dimensions of about 13 nm height and 100 nm width. The wire luminescence is found to be at λ=1575 nm (FWHM=17 meV).