The Study Of Amplified Spontaneous Emission From Polymer

The organic laser has many potential advantages:easy fabrication, low costs, tunable emission wavelength, large-scale integration. In recent years, conjugated organic semiconductor polymers have been one of the main research directions in organic optoelectronic materials due to their high fluorescence efficiency, large excitation cross section. In this paper, we discuss the amplified spontaneous emission (ASE) characteristics in MEH-PPV film and factors to influence ASE.Under the pump of 500nm pulse laser, ASE of the MEH-PPV waveguide with asymmetric structures was investigated. We found that the output intensity is lower and the full width at half maximum (FWHM) is wider when the pump intensity is lower. However, with the increasing pump intensity, the quick increase in output intensity y and the FWHM narrowing shows threshold characteristics. The threshold is 0.226μJ/pluse when the film is 93.3 nm and with the increase of film thickness the threshold drop to 0.16μJ/pluse, and the gain increase to 28.2 cm-1. However the thickness can not increase unlimitedly because of high attenuation coefficient and the pump energy can be used up rapidly. So we make the micron and 560 nm film to find the connection between stimulated emission and thickness.We also study ASE with similar MEH-PPV films spin-coated for different solvent. Compared with the other solvent, chlorobenzene is proper solvent because of it's specifics such as:boiling points, surface tension etc. After the AFM measurement, I confirm that the chlorobenzene film has the most smoothly surface, so chlorobenzene film has the best threshold and gain.