|Alguien dijo ...|
|Las proposiciones matemáticas, en cuanto tienen que ver con la realidad, no son ciertas; y en cuanto que son ciertas, no tienen nada que ver con la realidad.|
|Semiconductors To limit the Speed of the Light|
Although it seems a paradox, scientists of the Californian University of, in Berkeley, have slowed down the light in a effort to make the communications in the optical communications nets faster. In order to obtain it, they have used semiconducting. The investigators have reduced up to 10 km/s the speed at which a laser pulse travels throughout a luminance wave. This speed is not indeed slow, but it is comparing it it with which it experiences the light when traveling by the emptiness (300,000 km/s).
Previous experiments had demonstrated that the light rays can be slowed down or be accelerated when doing to pass them through atomic steam or crystal of solid state. For example, physicists of Harvard University had been able to stop light particles during 10 to 20 microseconds in rubidium gas. In the UC Berkeley something similar but using fine layers of semiconductors has been tried, that offer a remarkable bandwidth advantage as far as with respect to the crystal of solid state or the atomic steam. The use of semiconductors, in addition, allows to its implantation in given circuits photons. The scientists, headed by Connie J. Chang-Hasnain, hope with this technology to be able to transmit graphs in 3D, videoconferencia of hi-res, etc. At the moment, the optical signals move throughout the optical fiber to more than 100,000 km/s, until they reach some of many?cruces of highways? that they are in the way. Those points, the light signals are transformed into slower electronic data, so that they can to be read by routers, ordered to correct the way before convert a signal again to light. This optical-electronics-optical conversion is incredibly slow and expensive, which creates bottle necks which they make the network slower. Routers or enrutadores is like traffic lights in the intersections of the streets. With conversion OEO, we obtain something similar to which it would happen to him to a driver of a car that it had to lower of him, to speak with the director of the traffic, and to fill up several forms with its destiny before being able to continue. If we could control the speed of the light, would avoid conversion OEO and routers. it would restrain outside when necessary, avoiding to hit opposite against located others. At the present time, it is not possible to take advantage of the 20 teraherzios bandwidth available in the optical fiber due to the limitations that impose systems to us OEO. If we were able to surpass this obstacle, we could hardly transmit 600 films of two hours in 1 second. The experiments do not break any law of the physics, in special the one that says that the speed of the light is a physical constant that cannot be changed. What it is possible to be varied is the speed with which the amplitude of the wave of the light is transmitted. Many experiments have become that operate the way as the light is absorbed and dispersed when it interacts with the matter.
Martes, 02 Noviembre, 2004 - 11:00