“Excitoner”: Stimulated amplification and propagation of excitons' beams
Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas
Unicamp, 13083-970 Campinas, São Paulo, Brazil
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Accepted: 18 December 1999
A statistical-thermodynamic theory of the phenomenon of stimulated amplification of the population of excitons which lie at the bottom of their lowest-energy band is presented. The experimentally detected “packet” of excitons flowing ballistically is shown to consist of a Schrödinger-Davydov solitary wave, dressed with a cloud of incoherent excitons. Moreover, a secondary excitation by a c.w. laser beam promotes a Fröhlich-Bose-Einstein–like condensation, which is responsible for the relevant phenomenon that the lifetime of the soliton is largely increased with increasing pumping power.
PACS: 71.35.Lk – Collective effects (Bose effects, phase space filling, and excitonic phase transitions) / 42.65.-k – Nonlinear optics / 05.70.Ln – Nonequilibrium and irreversible thermodynamics
© EDP Sciences, 2000