Coherent Exciton Waves

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Science  06 Sep 1996:
Vol. 273, Issue 5280, pp. 1351-1352
DOI: 10.1126/science.273.5280.1351


Excitons are electrically neutral energetic pairs of electrons and holes, created by the absorption of photons in a solid. These energy-carrying pairs can be used to produce light for microscopes and are used by plants to collect sunlight for photosynthesis. In his Perspective, Snoke describes work carried out at Ecolé Polytechnique in Palaiseau, France, and the University of Ottawa, Canada, in which excitons were produced by stimulated emission. Such processes may someday be used to create a laserlike source of excitons.