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.

A strain-induced lateral variation of the band edges of a 10-nm-thick In0.16Ga0.84As quantum well embedded in GaAs is achieved by patterning of a 100-nm-thick compressively strained In0.52Ga0.48P stressor layer. The strain modulation results in a splitting of the 10 K far-field photoluminescence (PL) spectra into two emission peaks. Spectrally resolved two-dimensional near-field PL images establish a clear spatial and spectral separation of the two far-field PL peaks, indicating a lateral carrier confinement with a confinement energy of about 10 meV. Finite-element calculations of the strain distribution are used to determine the lateral band-edge shifts and are well in agreement with the experimental findings. (C) 2001 American Institute of Physics.

A detailed study of the structural disorder in wedge semiconductor microcavities (MC's) is presented. We demonstrate that images of the coherent emission from the MC surface can be used for a careful characterization of both intrinsic and extrinsic optical properties of semiconductor NIC's. The polariton broadening can be measured directly, avoiding the well-known problem of inhomogeneous broadening due to the MC wedge. A statistical analysis of the spatial line shape of the images of the MC surface shows the presence of static disorder associated with dielectric fluctuations in the Bragg reflector. Moreover, the presence of local fluctuations of the effective cavity length can be detected with subnanometer resolution. The analysis of the resonant Rayleigh scattering (RRS) gives additional information on the origin of the disorder. We find that the RRS is dominated by the scattering of the photonic component of the MC polariton by disorder in the Bragg reflector. Also the RRS is strongly enhanced along the [110] and [1 (1) over bar0] directions. This peculiar scattering pattern is attributed to misfit dislocations induced by the large thickness of the mismatched AlGaAs alloy in the Bragg mirrors.

Microphotoluminescence measurements under ew excitation reveal the existence of a strong photoluminescence up-conversion from single InAs/GaAs self-assembled quantum dots and also from the InAs wetting layer. Excitation spectroscopy of the up-converted photoluminescence signal shows identical features from the wetting layer and the single quantum dots, i.e., a band tail coming from the deep states localized at the rough interfaces of the wetting layer quantum well. This observation of photoluminescence up-conversion demonstrates the influence on the quantum dot properties of the environment, and highlights the limitations of the artificial atom model for a semiconductor quantum dot.

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.

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].