BLUE-GREEN LASER-EMISSION FROM A SOLID CONJUGATED POLYMER

We report on a highly efficient laser based on a pi-conjugated polymer blend system. The gain material consists of phenyl-substituted poly-( p-phenylenevinylene) (PPPV) blended into a polymethylmetacrylat (PMMA) matrix. The sample was placed into an external resonator and was tran sversally pumped. Here we present measurements on the pump-intensity d ependence of the emission spectra. At low pump-intensities an inhomoge neously broadened unstructured emission is observed. Increasing the pu mp-power above a certain threshold leads to spectral narrowing. Simult aneously, the output power rises superlinearly. (C) 1997 Elsevier Scie nce Ltd.