Highly-efficient, diffraction-limited laser emission from a Vertical External Cavity Surface-emitting Organic Laser

TL;DR

This paper demonstrates a highly efficient, diffraction-limited organic laser using a VECSEL-like structure with tunable spectrum and high peak power, advancing solid-state laser technology.

Contribution

It introduces a novel organic VECSEL design with high efficiency, diffraction-limited emission, and spectral tunability, which was not previously achieved in organic lasers.

Findings

Diffraction-limited beam with M^2=1 achieved.

Conversion efficiency of 43% demonstrated.

Peak power of 2 kW with shorter pump pulses.

Abstract

We report on a solid-state laser structure being the organic counterpart of the Vertical External-Cavity Surface-Emitting Laser (VECSEL) design. The gain medium is a poly (methyl methacrylate) film doped with Rhodamine 640, spin-casted onto the High-Reflectivity mirror of a plano-concave resonator. Upon pumping by 7-ns pulses at 532 nm, a diffraction-limited beam (M^2=1) was obtained, with a conversion efficiency of 43%; higher peak powers (2kW) could be attained when resorting to shorter (0.5 ns) pump pulses. The spectrum was controlled by the thickness of the active layer playing the role of an intracavity etalon; tunability is demonstrated over up to 20 nm.