Spectral narrowing in optically pumped poly (p‐phenylenevinylene) Films

Lasing in conjugated polymer thin films? Not so, according to the results presented here. As previously reported, for films of a variety of conjugated polymers on glass substrates the emission spectrum narrows with increasing optical‐pump intensity when pulsed excitation is used. A detailed study is described here of this spectral narrowing phenomenon using films of poly(p‐phenylenevinylene) (PPV). Evidence is presented that weakens the case for lasing being the mechanism involved and supports and supports amplification of spontaneous emission by waveguiding.