24-10-2012, 08:29 PM
A group of physicists from the University of Bonn have developed a "brand new" source of light, the so-called Bose-Einstein condensate consisting of photons. Until recently, scientists believed that the receipt of this source is not practicable. According to the researchers, the new method can be used to create new sources of light, such as lasers operating in the X-ray spectrum. Another application of the design would be to create super-computer chips. After cooling rubidium atoms and concentrating enough of them in a small space, the individual atoms of matter are indistinguishable from each other.
According to the researchers, the material in this case behaves like a single huge "super particle". Physicists call this phenomenon of Bose-Einstein condensate. For light particles, or photons, this technology also works, but not always. Unfortunately, in the case of light, this idea faces a fundamental problem - when photons fall into the super cooled environment, they disappear.
However, German experts have managed to overcome this problem: they were able to cool photons, concentrating them in the same place. This should probably explain what a "temperature of the light." The term is familiar to professional photographers, as well as physicists.
For example, when a tungsten filament bulb is heated, it begins to glow - first red, then yellow, and finally white and blue. Here blue warmer red. But tungsten glows differently than iron. This is why physicists apply the system temperature calibration based on a theoretical model, called the model of black bodies.
If the body is heated to 5,500 degrees Celsius, it begins to emit light, comparable to the sunlight at noon. In other words: noon light has a temperature of 5500 degrees, or about 5800 degrees Kelvin. However, when a perfect black body cools, it begins to emit light, which is no longer visible in the optical light, instead it emits infrared photons. At the same time, decreases the intensity of the radiation - the number of photons when the temperature decreases.
This factor makes it difficult to obtain a large amount of cooling photons required for Bose-Einstein condensation. Yet scientists from Bonn succeeded with the help of two mirrors with high reflectivity to launch a beam of light, which "jump" back and forth. Between the mirrors was a special pigment, dissolved in space - with him periodically clashed molecules. The clashes sometimes pigment molecules absorb photons, and then they put off. "In the course of the collision photons transmitted by ambient temperature. fact, they were cooled to room temperature," - said Professor Martin Weitz.
Bonn researchers were also able to increase the number of photons between the two mirrors with a laser. This allowed them to concentrate the cooled photons so tightly that they have to act like a "super-photon." photonic Bose-Einstein condensate, according to scientists, is a completely new source of light that has characteristics similar to a laser, but in fact the laser does not being.
"Now we are not able to produce lasers that generate very short-wave light, such as the X-ray spectrum. But with a new source of light as possible," - says Weitz. According to him, the opportunity should be of interest primarily manufacturers of processors. They use lasers for logic circuits in semiconductors. Positioning accuracy is dependent on the wavelength of the laser - a shortwave emitters should be significantly higher coefficient of accuracy.
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