Electromagnetically-induced transparency (EIT) is observed and analyzed for the group velocity of a femtosecond light pulse interacting with GaAs/AlGaAs multiple quantum wells (MQWs) in a transient regime. The calculated slowdown factor of the group velocity inside the medium due to the dynamic refractive index change is approximately 2.10 x 10(3). We discuss the potential of EIT-induced slow light in GaAs/AlGaAs MQWs for ultrafast (approximately 210 GHz) all-optical information processing such as photon routing.

Au nanoparticles exhibited both negative and positive nonlinear absorptions with ground-state plasmon bleaching and free-carrier absorption that could be origins of the saturable and reverse-saturable optical properties. Au/Ag coreshells displayed only positive nonlinear absorption and reverse-saturable optical properties as a function of excitation intensity at the edge of surface-plasmon resonance, which implies no ground-state plasmon bleaching and the existence of two-photon absorption.

This paper presents an investigation of a circumferential feed-back channel located on shroud surface in rotor domain to find its effects on aerodynamic performance of a single-stage axial compressor, NASA Stage 37, using three-dimensional Reynolds-averaged Navier-Stokes equations. Validation of numerical results was performed using experimental data for both of single rotor and single-stage compressors. A parametric study of the feed-back channel was performed using various geometric parameters related to the locations and shapes of the channel inlet and outlet. The numerical results showed that a reference circumferential feed-back channel increased the stall margin by 26.8% with 0.14% reduction in the peak adiabatic efficiency, compared to the case without the feed-back channel.

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