Linear wave dynamics explains observations attributed to dark-solitons in a polariton quantum fluid

We investigate the propagation and scattering of polaritons in a planar GaAs microcavity in the linear regime under resonant excitation. The propagation of the coherent polariton wave across an extended defect creates phase and intensity patterns with identical qualitative features previously attributed to dark and half-dark solitons of polaritons. We demonstrate that these features are observed for negligible nonlinearity (i.e., polariton-polariton interaction) and are, therefore, not sufficient to identify dark and half-dark solitons. A linear model based on the Maxwell equations is shown to reproduce the experimental observations.Comment: Article + Supplementary Information (tot. 18 pages

Experimental evidence for exciton scaling effects in self-assembled molecular wires

Journal ArticleResonant Rayleigh scattering from self-assembled one-dimensional molecular J-aggregate wires reveals a distinct dependence of the exciton energy on the width of lateral extension. For the J aggregates used in this study, strong in-line dipole coupling leads to a delocalization of the exciton wave function over several molecular units. Polarization dependent measurements of resonantly scattered light from the wires show that the exciton dipole moment is oriented perpendicular to the long axis. The experimental observations can be described by applying a quantization condition to the center of mass motion of the J-band exciton in the wires

Penrose-Onsager Criterion Validation in a One-Dimensional Polariton Condensate

We perform quantum tomography on one-dimensional polariton condensates, spontaneously occurring in linear disorder valleys in a CdTe planar microcavity sample. By the use of optical interferometric techniques, we determine the first-order coherence function and the amplitude and phase of the order parameter of the condensate, providing a full reconstruction of the single particle density matrix for the polariton system. The experimental data are used as input to theoretically test the consistency of Penrose-Onsager criterion for Bose-Einstein condensation in the framework of nonequilibrium polariton condensates. The results confirm the pertinence and validity of the criterion for a non equilibrium condensed gas.Comment: 5 pages, 4 figure

Single-mode tuneable laser operation of hybrid microcavities based on CdSe/CdS core/shell colloidal nanorods on silica microspheres

Colloidal core/shell semiconductor nanonorystals have generated a great deal of interest as gain media in recent years due to a number of salient properties originating from their small size and the associated quantum confinement [1]. These include low-threshold and temperature-insensitive lasing, reduced trapping of excited carriers, and the possibility to alleviate non-radiative Auger recombination by engineering the wavefunction distributions of the electrons, and holes within their volume. Here, single-mode, tuneable operation of fiber-coupled hybrid lasers based on colloidal CdSe/CdS core/shell nanorods on silica microspheres is reported

Ultimate photo-induced Kerr rotation achieved in semiconductor microcavities

Photoinduced Kerr rotation by more than $\pi /2$ radians is demonstrated in planar quantum well microcavity in the strong coupling regime. This result is close to the predicted theoretical maximum of $\pi$. It is achieved by engineering microcavity parameters such that the optical impedance matching condition is reached at the smallest negative detuning between exciton resonance and the cavity mode. This ensures the optimum combination of the exciton induced optical non-linearity and the enhancement of the Kerr angle by the cavity. Comprehensive analysis of the polarization state of the light in this regime shows that both renormalization of the exciton energy and the saturation of the excitonic resonance contribute to the observed optical nonlinearities.Comment: Shortened version prepared to submit in Phys. Rev. Letter