Stretched input-output characteristic in inhomogeneously broadened 1asing system

We have measured the input-output curve of an organic vertical-cavity surface-emitting laser (OVCSEL), made of Alq3:DCM, over more than 2 orders of magnitude beyond threshold. The characteristics cannot be explained by the standard theory of lasing, which uses a single spontaneous emission factor, beta. By assuming an inhomogeneously broadened distribution of beta values we are able to qualitatively model the observed input-output curve.