Physicists from Russia and foreign countries have created a new type of compact nanolaser that can be used as a basis for light and quantum computers of the future, RIA Novosti reported . This is stated in an article published in the journal Physical Review Letters .
“Polaritons offer an alternative platform for quantum computing.” Most importantly, as demonstrated by our work with a group in Michigan, the polariton condensates feel great at room temperature. “I am convinced that a semiconductor platform for quantum technology can be created in Russia in a short time. we could even overtake Google, “said Alexei Kavokin from St. Petersburg State University.
Polaritons are one of the relatively newly created virtual particles that, like a photon, simultaneously behave like a wave and as a particle. It consists of three components – an optical resonator (a set of two reflecting mirrors), a light wave suspended between them and a quantum well – an atom and an electron rotating around it, which periodically absorbs and emits a quantum of light.
As recent experiments and theoretical calculations of Russian physicists show, polaritons can be used as carriers of information in light and quantum computers of the future, as well as as a basis for various compact light sources and other forms of electromagnetic radiation.
According to Kavokin, over the past few years, both Russian and foreign scientists have used this property of polaritons to create compact lasers that can operate at room temperature and consume very little energy. Despite such advantages, such lasers could not be used in practice, since their design in principle did not allow them to control their polarization, which is critically important for the transmission and coding of information.
Kavokin and his colleagues from the University of ITMO, as well as the United States, Britain and Italy were able to solve this problem by “violating” the laws of physics governing the behavior of electrons and how they participate in pumping the laser. On polaritons, as scholars note, such restrictions do not always work, since at very low temperatures they turn into a special exotic form of matter, the so-called Bose-Einstein condensate.
“Usually two Bose-Einstein condensates are formed in a polariton laser, both condensates emit independently, and as a result, the direction of polarization is random.If one condensate could be pumped up, it would, firstly, be able to obtain stable circularly polarized radiation, and second, to further reduce energy consumption, “explains Ivan Iorsh, associate professor at the ITMO University in St. Petersburg.
Russian and foreign scientists understood how to solve this problem and forced the polaritons to work at room temperature, using an unusual source of electrons – a fragment of a ferromagnetic material, an alloy of iron, cobalt and magnesium oxide. As the researchers note, the properties of electrons in them can be controlled by an external magnetic field, which allows a flexible and rapid change in the polarization of the laser radiation generated by these electrons.
Such lasers, as noted by Kavokin, will not only accelerate the operation of conventional fiber-optic networks, but also create light and quantum computers operating at room temperatures. This will simplify their design and bring us closer to their creation, scientists conclude.
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