Exciton center-of-mass dispersion in semiconductor quantum wells

We discuss the results of the calculation of the exciton center-of-mass dispersion in a semiconductor quantum well. Strong nonparabolicity arises due to the coupling among the excitons related to the heavy and light holes. We consider the effects of the coupling in the exciton dynamics by calculating the exciton average mass and spin.5642094210

Electron-spin polarization near the Fermi level in n-type modulation-doped semiconductor quantum wells

We study the spin polarization of optically created electrons near the Fermi energy in an n-type modulation-doped single quantum well. In our system the Fermi level is slightly above the second confined conduction subband. The results reveal that electrons optically created close to the Fermi level partially conserve their spin polarization, despite the presence of the electron gas. Data obtained by changing the excitation intensity show that exchange interaction among optically created electrons and holes dominates the spin flip processes in the vicinity of the Fermi edge. [S0163-1829(99)51412-4].5912R7813R781

Interference effect in the resonant emission of a semiconductor microcavity

We present a phenomenological description of the coherent emission from a semiconductor microcavity in the strong-coupling regime. We consider two main contributions which are calculated in the framework of the semiclassical approach of the linear dispersion theory: reflectivity corresponds to the response of a uniform microcavity while resonant Rayleigh scattering (RRS) arises from disorder. Our simulations are compared to experimental results obtained at normal incidence in a backscattering geometry by means of cw spectroscopy and interferometric correlation with subpicosecond resolution. In this geometry, a fair agreement is reached assuming interferences between the two aforementioned contributions. This interference effect gives evidence of the drastic modification of the RRS emission pattern of the embedded quantum well induced by the Fabry-Perot cavity

Polariton-acoustic-phonon interaction in a semiconductor microcavity

The broadening of polariton lines by acoustic phonons is investigated in a semiconductor microcavity by means of interferometric correlation measurements with subpicosecond resolution. A decrease of the polariton-acoustic phonon coupling is clearly observed for the lower polariton branch as one approaches the resonance between exciton and photon states. This behavior cannot be explained in terms of a semiclassical linear dispersion theory but requires a full quantum description of the microcavity in the strong-coupling regime

Interface roughness localization in quantum wells and quantum wires

We studied the effects of interface localization due to microroughness in a sample presenting a quantum well and a quantum wire. We measured the magnetoluminescence at different temperatures and analyzed the results with a model where the average microroughness, the magnetic field, and the excitonic effects are treated within the same level of approximation. We were able to extract a quantitative estimate for the exciton localization due to microroughness. Our results also demonstrate the efficiency of the temperature to detrap excitons from the interface roughness localization. [S0163-1829(98)03439-0].58159876988

Stationary coherence in semiconductor microcavities

We have investigated the coherent dynamics of a semiconductor microcavity by means of interferometric correlation measurements with fs resolution. We bring clear evidence of the resolution of a homogeneous polariton line in an inhomogeneously broadened exciton system. Moreover, we observe an unexpected stationary coherence up to 8 ps for the lower polariton branch close to resonance. Linear dispersion theory including an exciton asymmetric inhomogeneous broadening accounts for the coherent dynamics but does not predict the stationary coherence. [S0163-1829(99)51616-0]

Nonlinear optical properties of glass

Numerous innovations in photonics have been realized on the basis of nonlinear optical properties, notably in information technologies. Totake advantage of the nonlinear optical properties of glass, multidisciplinary research efforts were necessary, combining optics, glass chemistry,material science, as well as development of optical or electrical polarizations processes. This chapter addresses both fundamental aspects of nonlinear optical responses and also the exploitation of nonlinear optical phenomena in glassy material. It starts by a general introduction to nonlinear optical phenomena and concepts. Then, the specific cases of second and third optical responses in glasses are treated separately and described in detail as a function of the corresponding optical phenomena, the various glass families, and their applications