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

TL;DR

This paper investigates the coexistence of vertical-cavity and random lasing in a blue-emitting organic crystal, revealing a novel surface-emitting configuration with competitive mode dynamics and potential for advanced photonic applications.

Contribution

It demonstrates the simultaneous operation of vertical-cavity and random lasing in a molecular crystal, highlighting a new surface-emitting configuration and the interplay between different lasing mechanisms.

Findings

Narrow peaks due to Fabry-Pérot and random resonances observed

Lasing threshold around 500 microJ cm^-2 identified

Anti-correlation between modes due to gain competition

Abstract

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-P\'erot 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-P\'erot cavity and random lasing in a novel, surface-emitting configuration and threshold around 500 microJ 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.