ScienceDaily (July 3, 2009) — ETH Zurich researchers have successfully created an optical transistor from a single molecule. This has brought them one step closer to an optical computer.
Internet connections and computers need to be ever faster and more powerful nowadays. However, conventional central processing units (CPUs) limit the performance of computers, for example because they produce an enormous amount of heat. The millions of transistors that switch and amplify the electronic signals in the CPUs are responsible for this. One square centimeter of CPU can emit up to 125 watts of heat, which is more than ten times as much as a square centimeter of an electric hotplate.
Photons instead of electrons
This is why scientists have been trying for some time to find ways to produce integrated circuits that operate on the basis of photons instead of electrons. The reason is that photons do not only generate much less heat than electrons, but they also enable considerably higher data transfer rates.
An artist vies of a photonic circuit with molecular building blocks. A single-molecule optical transistor is depicted using a standard symbol for an electronic transistor. (Credit: Robert Lettow)
Although a large part of telecommunications engineering nowadays is based on optical signal transmission, the necessary encoding of the information is generated using electronically controlled switches. A compact optical transistor is still a long way off. Vahid Sandoghdar, Professor at the Laboratory of Physical Chemistry of ETH Zurich, explains that, “Comparing the current state of this technology with that of electronics, we are somewhat closer to the vacuum tube amplifiers that were around in the fifties than we are to today’s integrated circuits.”
However, his research group has now achieved a decisive breakthrough by successfully creating an optical transistor with a single molecule. For this, they have made use of the fact that a molecule’s energy is quantized: when laser light strikes a molecule that is in its ground state, the light is absorbed. As a result, the laser beam is quenched. Conversely, it is possible to release the absorbed energy again in a targeted way with a second light beam. This occurs because the beam changes the molecule’s quantum state, with the result that the light beam is amplified. This so-called stimulated emission, which Albert Einstein described over 90 years ago, also forms the basis for the principle of the laser.
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NOTA IMPERTINENTE DESTE BLOGGER:
O computador ótico ainda está a caminho. A sua complexidade nos deixa maravilhados, e nem temos dúvidas de que temos aqui um exemplo de design inteligente. O cérebro humano é muito mais complexo do que este computador ótico que os cientistas estão tentando construir.
O cérebro humano, que a ciência até agora pouco sabe, tem a sua origem no acaso, necessidade ou design inteligente???
