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CPP: Chemische Physik und Polymerphysik

CPP 18: Poster: Polymer Blends, Heterogeneous Systems, Colloids and Nanoparticles, Interfaces, Polyelectrolytes

CPP 18.16: Poster

Wednesday, April 4, 2001, 12:30–15:00, AT1

Organic random laser utilizing a two-dimensional colloidal crystal — •Stefan Riechel¹, Carmen Klingler-Deiseroth¹, Uli Lemmer¹, Jochen Feldmann¹, Anton G. Mückl², and Wolfgang Brütting² — ¹Lehrstuhl für Photonik und Optoelektronik, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 München — ²Lehrstuhl Experimentalphysik II, Universität Bayreuth, Universitätsstr. 30, 95440 Bayreuth

We report on the realisation of an optically pumped organic random laser. Using a self-assembly technique monolayers of a two-dimensional colloidal crystal are fabricated from a dispersion of polystyrene beads. On top of the colloidal crystal a thin film of the organic semiconductor laser material Alq₃:DCM is deposited by thermal evaporation in high vacuum. Above a threshold excitation intensity an increasingly large number of spectrally narrow laser modes appears in the emission spectrum. These features indicate feedback due to multiple scattering and the formation of random closed loop paths.