SPATIALLY DEPENDENT AMPLIFICATION OF AN EXCITONIC BOSE-EINSTEIN CONDENSATE IN Cu2O

Abstract

Experimental results are presented on the spatial dependence of amplification of a travelling Bose-Einstein condensate of excitons in Cu 2 O . The exciton condensate is created at T = 1.8 K by high intensity pulsed laser illumination (λ = 532 nm). Amplification of the moving condensate is triggered by the local, time-delayed injection of thermal excitons created by a lateral laser pulse tuned at the 1S orthoexciton resonance (λ = 609.48 nm), perpendicular to the path of the condensate. The amplification factor depends on the trigger time of the lateral laser pulse and is related to the stimulated scattering into the condensate of non-condensed excitons present in the crystal volume. A spatial correlation is also observed between the amplification factor and the optical attenuation of the lateral laser radiation induced by the passing condensate.