The Study On Amplified Spontaneous Emission Of Polymer Waveguide

Semiconducting polymers are promising materials in solid-state lasers on account of their high photoluminescence quantum efficiency (PLQE), simple fabrication, mechanical flexibility, and broad spectra. Recently optically pumped lasers based on conjugated polymer have been already realized in both solution and film. Therefore more and more efforts have been made to demonstrated electrically pumped lasers by improving the current injection and lowering their lasing threshold. In this thesis, our work is focused on the optimization of the structure and materials of polymer laser in order to reduce the threshold for amplified spontaneous emission (ASE).(1) We investigate the ASE of polymer waveguide with grating structure. DFB waveguides based on MEH-PPV films were ablated by UV laser. The lasing character of DFB waveguides is optimized by the grating structure.(2) We also study the character of ASE for F8BT:P3HT blend waveguides. Attributing to its low thresholds for ASE and high carrier mobility, F8BT:P3HT might be a good material for electrically pumped polymer laser. Blends with≤20wt.%fraction of P3HT shows relatively lower threshold than F8BT. Also, we demonstrated that the decrease in ASE threshold of blend waveguides is resulted from the reduction of loss of the blend waveguides.(3) We investigate the electric-field modulated ASE of F8BT:P3HT blend waveguides. Electric-field-induced quenching of the ASE was significantly enhanced in blends compared with pristine F8BT, and the quenching factor of ASE increases with increasing P3HT fractions in blends, which permits that the gain of blend waveguide can be modulated more easily.