Polariton laser

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A polariton laser is a form of laser that takes advantage of the coherent nature of a Bose condensate of exciton polaritons to achieve particularly energy efficient laser operation.

The concept behind it was already in 1996 by Atac Imamoglu et al. explains and is based on an effect very closely related to the Bose-Einstein condensation of atoms: through stimulated scattering, a large number of bosonic particles (here polaritons) are collected in a macroscopically occupied quantum state, the so-called condensate. The condensate of polaritons ultimately creates coherent emission of light. Due to this functionality, which is very different from that of conventional lasers, the polariton laser enables components to be produced with significantly reduced power consumption. The typical semiconductor structure for such a laser consists of an optical microcavity which is surrounded by Bragg mirrors .

An early demonstration of polaritonic lasing and a comparison to the regular laser was achieved by H. Deng et al. under optical stimulation already in 2003 at Stanford University (polariton condensation was later in 2006 by Kasprzak et al. also completely associated with Bose-Einstein condensation ). The first experimental demonstration of a polaritone laser under electrical excitation, which is decisive for the practical use of polaritone light sources, was finally succeeded by a research team from the University of Würzburg with its international cooperation partners.

In particular, the distinction between a polariton laser and a conventional (photon) laser turns out to be difficult, since the emission characteristics are very similar. The key lies in the material component of the polariton, which reacts sensitively to a magnetic field. The investigations that the team in Würzburg had brought to the desired effects after a few years in cooperation with international partners in the USA, Japan, Russia, Singapore, Iceland and Germany since the idea of ​​realizing an electrical component in 2007, were finally over An important experiment in the magnetic field was added: This enabled the material content of the emission mode to be clearly verified in polariton laser operation, which led to the first experimental demonstration of a polariton laser by C. Schneider and A. Rahimi-Iman together with their co-authors in the research team of S. Höfling led (published in Nature in May 2013).

References

  1. ↑ a b Deng. H., Weihs, G .; Snoke, D .; Bloch, J. & Yamamoto, Y .: Polariton lasing vs. photon lasing in a semiconductor microcavity . In: Proc. Natl Acad. Sci. USA . 100, 2003, pp. 15318-15323.
  2. ↑ a b Schneider, C., Rahimi-Iman, A; Kim, NY; Fischer, J .; Savenko, IG; Amthor, M .; Lermer, M .; Wolf, A .; Worschech, L .; Kulakovskii, VD; Shelykh, IA; Kamp, M .; Reitzenstein, S .; Forchel, A .; Yamamoto, Y. & Höfling, S .: An electrically pumped polariton laser . In: Nature . 497, 2013, pp. 348-352. doi : 10.1038 / nature12036 .
  3. ↑ Imamoglu, A., Ram, RJ; Pau, S. & Yamamoto, Y .: Nonequilibrium condensates and lasers without inversion: exciton-polariton lasers . In: Phys. Rev. A . 53, 1996, pp. 4250-4253. doi : 10.1103 / PhysRevA.53.4250 .
  4. ↑ Kasprzak, J., Richard, M .; Kundermann, S .; Baas, A .; Jeambrun, P .; Keeling, JMJ; Marchetti, FM; Szymanska, MH; André, R .; Staehli, JL; Savona, V .; Littlewood, PB; Deveaud, B. & Dang, LS: Bose-Einstein condensation of exciton polaritons . In: Nature . 443, 2006, pp. 409-414. doi : 10.1038 / nature05131 .
  5. ^ University of Würzburg: A new type of laser . May 16, 2013. Archived from the original on October 17, 2013. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved October 17, 2013. @1@ 2Template: Webachiv / IABot / www.uni-wuerzburg.de
  6. ↑ pro-physik.de: How a polariton laser works . May 17, 2013. Retrieved October 17, 2013.