Confinement of pyridinium hemicyanine dye within an anionic metal-organic framework for two-photon-pumped lasing

TLDR

Two‑photon‑pumped dye lasers are important for applications such as wavelength up‑conversion, optical data storage, biological imaging, and photodynamic therapy, but solid‑state realization is hindered by aggregation‑caused quenching and other loss processes. The study demonstrates a new two‑photon‑pumped micro‑laser by encapsulating a cationic pyridinium hemicyanine dye into an anionic metal‑organic framework. The authors encapsulate the dye into the MOF to create the micro‑laser. The MOF⊃dye composite shows strong two‑photon fluorescence and 640‑nm lasing under 1064‑nm pulsed excitation, with reduced aggregation‑caused quenching, demonstrating a synergistic two‑photon‑pumped lasing functionality that could advance solid‑state photonic devices.

Abstract

Two-photon-pumped dye lasers are very important because of their applications in wavelength up-conversion, optical data storage, biological imaging and photodynamic therapy. Such lasers are very difficult to realize in the solid state because of the aggregation-caused quenching. Here we demonstrate a new two-photon-pumped micro-laser by encapsulating the cationic pyridinium hemicyanine dye into an anionic metal-organic framework (MOF). The resultant MOF⊃dye composite exhibits significant two-photon fluorescence because of the large absorption cross-section and the encapsulation-enhanced luminescent efficiency of the dye. Furthermore, the well-faceted MOF crystal serves as a natural Fabry–Perot resonance cavity, leading to lasing around 640 nm when pumped with a 1064-nm pulse laser. This strategy not only combines the crystalline benefit of MOFs and luminescent behaviour of organic dyes but also creates a new synergistic two-photon-pumped lasing functionality, opening a new avenue for the future creation of solid-state photonic materials and devices. Two-photon-pumped dye lasers are useful for applications such as biological imaging; however, loss processes reduce their efficiency. Here, metal-organic frameworks, into which the laser dye is incorporated, demonstrate enhanced laser operation because losses such as dye aggregation-caused quenching are reduced.