Origin of Optical Gain and Stimulated Emission in Conjugated Polymers

Recent reports on a spectrally narrow emission peak have generated a lot of excitement in the scientific community. Hide et al. [1] and Frolov et al. [2] reported dramatic photoluminescence (PL) line narrowing in a variety of PPV derivative films for exciton densities above 1017 cm-3, indicating stimulated emission (SE). The SE linewidth (7 to 9 nm) has been attributed to either amplified spontaneous emission [1] or superradiance [2].