Waveguide (optics)An optical waveguide is a physical structure that guides electromagnetic waves in the optical spectrum. Common types of optical waveguides include optical fiber waveguides, transparent dielectric waveguides made of plastic and glass, liquid light guides, and liquid waveguides. Optical waveguides are used as components in integrated optical circuits or as the transmission medium in local and long-haul optical communication systems.
Roquette (arme)vignette|Fantassin de l'armée de terre française en position de tir avec un lance-roquette (RPG : rocket-propelled grenade) Apilas. Arme antichar standard à la fin des années 1980 et dans les années 1990. vignette|Tir de TOS-1 russe. vignette|Roquettes Hydra-70 dans un lanceur M261 à 19 tubes équipant un hélicoptère d'attaque AH-64 Apache des forces armées néerlandaises. Une roquette est un projectile non-guidé propulsé par un moteur-fusée.
Shoulder-fired missileShoulder-fired missile, shoulder-launched missile or man-portable missile, among other variants, are common slang-terms to describe high-caliber shoulder-mounted weapons systems – that is: weapons firing large heavy projectiles ("missiles"), typically using the backblast principle, which are small enough to be carried by a single person and fired while held on one's shoulder. The word "missile" in this context is used in its original broad sense of a heavy projectile, and encompasses all shells and rockets, guided or unguided (compare with guided missile).
Optical resolutionOptical resolution describes the ability of an imaging system to resolve detail, in the object that is being imaged. An imaging system may have many individual components, including one or more lenses, and/or recording and display components. Each of these contributes (given suitable design, and adequate alignment) to the optical resolution of the system; the environment in which the imaging is done often is a further important factor. Resolution depends on the distance between two distinguishable radiating points.
HolographieL'holographie est un procédé d'enregistrement de la phase et de l'amplitude de l'onde diffractée par un objet. Ce procédé d'enregistrement permet de restituer ultérieurement une image en trois dimensions de l'objet. Ceci est réalisé en utilisant les propriétés de la lumière cohérente issue des lasers. Le mot « holographie » vient du grec holos (« en entier ») et graphein (« écrire »). Holographie signifie donc « tout représenter ».
Transmission mediumA transmission medium is a system or substance that can mediate the propagation of signals for the purposes of telecommunication. Signals are typically imposed on a wave of some kind suitable for the chosen medium. For example, data can modulate sound, and a transmission medium for sounds may be air, but solids and liquids may also act as the transmission medium. Vacuum or air constitutes a good transmission medium for electromagnetic waves such as light and radio waves.
