Random lasing in an organic light-emitting crystal and its interplay with vertical cavity feedback

The simultaneous vertical-cavity and random lasing emission properties of a blue-emitting molecular crystal are investigated. The 1,1,4,4-tetraphenyl-1,3-butadiene samples, grown by physical vapour transport, feature room-temperature stimulated emission peaked at about 430 nm. Fabry-Pérot and random resonances are primed by the interfaces of the crystal with external media and by defect scatterers, respectively. The analysis of the resulting lasing spectra evidences the existence of narrow peaks due to both the built-in vertical Fabry-Pérot cavity and random lasing in a novel, surface-emitting configuration and threshold around 500 μJ cm-2. The anti-correlation between different modes is also highlighted, due to competition for gain. Molecular crystals with optical gain candidate as promising photonic media inherently supporting multiple lasing mechanisms. The interplay between vertical-cavity and random lasing emission properties of a blue-emitting molecular crystal is investigated. The emission spectra of the 1,1,4,4-tetraphenyl-1,3-butadiene samples show narrow peaks for excitation threshold >500 μJ cm-2, attributed to both the built-in vertical Fabry-Pérot cavity and random lasing. These results pave the way for the realization of solid-state lasers exploiting various amplification routes based on organic crystals. © 2014 The Authors. Laser & Photonics Reviews published by Wiley-VCH Verlag GmbH & Co. KGaA Weinheim.