Magneto-optic contact for application in an amplifying waveguide optical isolator

We present the development of a metal-semiconductor contact for a TM-mode amplijying waveguide optical isolator and show that it is a compromise between good (magneto-)optical performance and good electrical behavior

A Rapid Crosstalk of Human γδ T Cells and Monocytes Drives the Acute Inflammation in Bacterial Infections

Vγ9/Vδ2 T cells are a minor subset of T cells in human blood and differ from other T cells by their immediate responsiveness to microbes. We previously demonstrated that the primary target for Vγ9/Vδ2 T cells is (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP), an essential metabolite produced by a large range of pathogens. Here we wished to study the consequence of this unique responsiveness in microbial infection. The majority of peripheral Vγ9/Vδ2 T cells shares migration properties with circulating monocytes, which explains the presence of these two distinct blood cell types in the inflammatory infiltrate at sites of infection and suggests that they synergize in anti-microbial immune responses. Our present findings demonstrate a rapid and HMB-PP-dependent crosstalk between Vγ9/Vδ2 T cells and autologous monocytes that results in the immediate production of inflammatory mediators including the cytokines interleukin (IL)-6, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and oncostatin M (OSM); the chemokines CCL2, CXCL8, and CXCL10; and TNF-related apoptosis-inducing ligand (TRAIL). Moreover, under these co-culture conditions monocytes differentiate within 18 hours into inflammatory dendritic cells (DCs) with antigen-presenting functions. Addition of further microbial stimuli (lipopolysaccharide, peptidoglycan) induces CCR7 and enables these inflammatory DCs to trigger the generation of CD4+ effector αβ T cells expressing IFN-γ and/or IL-17. Importantly, our in vitro model replicates the responsiveness to microbes of effluent cells from peritoneal dialysis (PD) patients and translates directly to episodes of acute PD-associated bacterial peritonitis, where Vγ9/Vδ2 T cell numbers and soluble inflammatory mediators are elevated in patients infected with HMB-PP-producing pathogens. Collectively, these findings suggest a direct link between invading pathogens, microbe-responsive γδ T cells, and monocytes in the inflammatory infiltrate, which plays a crucial role in the early response and the generation of microbe-specific immunity

Mélange à quatre ondes intracavité et fonctions logiques optiques

Une nouvelle technique utilisant le mélange intracavité de quatre ondes quasi dégénérées en fréquence et l'injection optique permet la réalisation de portes logiques optiques. Cette technique est fondée sur le filtrage de fréquence d'ondes interagissant de façon non linéaire dans des diodes laser à semiconducteur. Après un exposé du principe, le cas des portes OU, INV et ET est spécifiquement étudié. Avantages et inconvénients de la technique sont également discutés

Mélange à quatre ondes intracavité et fonctions logiques optiques

A new technique using intracavity nearly degenerate four-wave mixing and injection-locking processes permits the realization of optical logic gates. This technique is based on frequency filtering of waves interacting nonlinearly in semiconductor laser diodes. The principle of this technique is described, with OR, INV, and AND gates being specifically studied. Advantages and disadvantages of this technique are also discussed.Une nouvelle technique utilisant le mélange intracavité de quatre ondes quasi dégénérées en fréquence et l'injection optique permet la réalisation de portes logiques optiques. Cette technique est fondée sur le filtrage de fréquence d'ondes interagissant de façon non linéaire dans des diodes laser à semiconducteur. Après un exposé du principe, le cas des portes OU, INV et ET est spécifiquement étudié. Avantages et inconvénients de la technique sont également discutés

INTERPRETATION OF INTRACAVITY INSTABILITIES IN TERMS OF DYNAMIC STARK EFFECT

Les oscillations de relaxation se produisant dans des cavités Fabry-Pérot amplificatrices ou absorbantes sont analysées en terme d'effet Stark dynamique dans un système à deux niveaux équivalent. Plusieurs applications potentielles de cette analyse sont également absordées : détermination de la fréquence de relaxation, analyse de la stabilité du dispositif et origine du doublement de période dans la route qui mène au chaos.Relaxation Oscillations in amplifying or absorbing-good or bad Fabry-Perot cavities are analyzed in terms of the dynamic Stark effect in an equivalent two-level system. Potential applications of this analysis are also presented : determination of the relaxation oscillation frequency, study of the stability criterions, and origin of period doubling in the route towards chaos