Nanoparticle-doped electrospun fiber random lasers with spatially extended light modes

TL;DR

This study demonstrates that nanoparticle-doped electrospun fiber mats can support large-scale, spatially extended optical modes in random lasers, enhancing spectral selectivity and mode correlation in disordered nanofiber networks.

Contribution

It provides new insights into the spatial extent and behavior of optical modes in nanoparticle-doped electrospun fiber random lasers, highlighting mechanisms for improved spectral control.

Findings

Random lasing with sub-nm spectral width achieved.

Presence of large spatial extent modes up to 100 micrometers.

Evidence of emission coupling into nanofiber transmission channels.

Abstract

Complex assemblies of light-emitting polymer nanofibers with molecular materials exhibiting optical gain can lead to important advance to amorphous photonics and to random laser science and devices. In disordered mats of nanofibers, multiple scattering and waveguiding might interplay to determine localization or spreading of optical modes as well as correlation effects. Here we study electrospun fibers embedding a lasing fluorene-carbazole-fluorene molecule and doped with titania nanoparticles, which exhibit random lasing with sub-nm spectral width and threshold of about 9 mJ cm^-2 for the absorbed excitation fluence. We focus on the spatial and spectral behavior of optical modes in the disordered and non-woven networks, finding evidence for the presence of modes with very large spatial extent, up to the 100 micrometer-scale. These findings suggest emission coupling into integrated nanofiber transmission channels as effective mechanism for enhancing spectral selectivity in random lasers and correlations of light modes in the complex and disordered material.