Improvement of amplified spontaneous emission performance of conjugated polymer waveguides with a low loss cladding

We report the improvement of the amplified spontaneous emission (ASE) performance in the optically pumped symmetric thin film waveguide glass/indium-tin oxide (ITO)/SiO2/poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene]/SiO2/Al or Ag by optimizing the thickness of SiO2 and replacing the Al electrode with Ag, where SiO2 acted as a spacer layer to prevent the ASE at 620 nm from being destructed. The results show that the SiO2/Ag cladding reduced the ASE threshold to 4 mu J/pulse compared with the SiO2/Al cladding, owing to the higher work function and reflection rate as well as lower absorption loss of the Ag electrode. No photoluminescence at 580 nm being observed makes it possible for an electric field to only modulate the ASE at 620 nm in the device with the SiO2/Ag cladding. The electric-field quenching of the ASE has been observed, which increases with the electric field. The field dependence of ASE can be attributed to field-induced dissociation of photogenerated excitons in the polymer waveguides. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4758927]