Continuously tunable laser emission from a wedge-shaped organic microcavity

Abstract

We present an organic microcavity laser with wide tunability in the range of 595–650nm, having a threshold as low as 2nJ/pulse. The active medium consists of the organic composite tris(8-hydroxy quinoline) aluminum (Alq3) and 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) embedded in between two distributed Bragg reflectors. The inhomogeneously broadened emission from DCM is exploited for lasing by means of a tunable Fabry–Perot-type interferometer. Continuous tuning is achieved by varying the thickness of the active layer. The device shows a high photostability under direct excitation in the absorption band of the guest molecule, thus, allowing to monitor the optical gain spectrum of the active medium.