Friday, February 09, 2007

Light to matter conversion and viceversa.

http://www.youtube.com/watch?v=QxbutNmaL-s



American researchers were able to disappear a beam of light, making it reappear in another side, using as slowers 2 clouds of atoms of sodium, separated 1 mm, among them. A light pulse stopped and extinguished in one box is revived from a completely different box in a separate location and sent back on its way. In the actual experiment, a slow light pulse was stopped and stored in one Bose–Einstein condensate (the first 'box'), then revived from a different condensate, 160 μm away. Information was transferred by converting the optical pulse into a travelling matter wave more amenable to manipulation than light. In this case, a first beam of light was thrown against a cloud of atoms of sodium, where after being captured (conversion of light in matter), left a cast of light inside the atoms. A second laser sent to a second near cloud of atoms of sodium, revived the original pulse recapturing the speed of the light with the same form and longitude of wave of the original although something weakened. It is believed that these experiments will allow an experimental bigger control of light and matter: dispositives of optic storage, quantum but quick and powerful computers. Instead of optic fibers, boxes full with wires and/or chips : data and images will be read directly of the light. The quantum procedure exploits the properties of the matter supercooled: Bose Einstein Condensation (under conditions near to absolute zero, a great fraction of atoms with spin 1 :bosones, collapses and condensed (superatoms), thanks to states of lowest quantum effect emerging to macroscopic scale). It was predicted by A. Einstein (1925), based on statistical works of photons carried out by the hindu S.N. Bose. Already in 1990 a team of Harvard had achieved slowed the speed of the light from 299,792km/s to 61km/h, using as controls, clouds of atoms of sodium (light was caught in the vacuum, to temperatures a little above the zero absolute: -273 Celsius).

Conversion de luz a materia y viceversa


Investigadores americanos lograron desaparecer un haz de luz, haciendolo reaparecer en otro lado, empleando como enlentecedores 2 nubes de atomos de sodio, separadas 1 mm, entre si. En este caso, un primer pulso de luz fue lanzado contra una nube de atomos de sodio, donde tras ser capturado (conversión de luz en materia), dejaba un molde de luz en el interior de los atomos. Un segundo laser enviado a una segunda nube de atomos de sodio cercana, revivio el pulso original retomando la velocidad de la luz con la misma forma y longitud de onda del original aunque algo debilitada. Se cree que estos experimentos permitiran un mayor control experimental de la luz y materia : dispositvos de almacenamiento optico, computadoras cuanticas mas rapidas y poderosas. En lugar de fibras opticas, cajas llenas de alambres y/o chips; datos e imagenes seran leidas directamente de la luz. El procedimiento cuantico explota las propiedades de la materia superfria : Condensado de Bose-Einstein (en condiciones superfrias cercanas al zero absoluto, una gran fraccion de atomos /bosones de spin 1/, colapsa condensandose (superatomos), merced a estados de muy bajo efecto cuantico emergiendo a escala macroscopica). Fue predicho por A. Einstein (1925), basandose en trabajos estadisticos de fotones realizados por el hindu S.N. Bose. Ya en 1990 un team de Harvard habia logrado enlentecer la velocidad de la luz de 299,792km/s a 61km/h, empleando como frenos, nubes de atomos de sodio (luz era atrapada en el vacio, a temperaturas un poco por encima del zero absouto :-273 Celsius).

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