Europhys. Lett., 49 (5), p. 637 (2000)

"Excitoner'': Stimulated amplification and
propagation of excitons' beams

Á. R. Vasconcellos - M. V. Mesquita - R. Luzzi

Instituto de Física "Gleb Wataghin'', Universidade Estadual de Campinas
Unicamp, 13083-970 Campinas, São Paulo, Brazil

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

Abstract:

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.

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