Bio-inspired polymers with polaritonic properties from visible to infrared: a material playground to mimic purple bacteria light-harvesting resonators

TL;DR

This paper develops bio-inspired organic materials with tunable polaritonic properties mimicking purple bacteria light-harvesting complexes, enabling subwavelength light confinement and potential applications in organic metamaterials.

Contribution

It introduces a library of J-aggregate-based nanostructures with tunable polaritonic properties inspired by biological systems, demonstrating their resonant light-matter interactions.

Findings

Nanorings of J-aggregates act as subwavelength resonators.

Polaritonic properties can be tuned from visible to infrared.

Electromagnetic simulations show strong light confinement.

Abstract

Light-harvesting complexes in natural photosynthetic systems, such as those in purple bacteria, consist of photo-reactive chromophores embedded in densely packed "antenna" systems organized in well-defined nanostructures. In the case of purple bacteria, the chromophore antennas are composed of natural J-aggregates such as bacteriochlorophylls and carotenoids. Inspired by the molecular composition of such biological systems, we create a library of organic materials composed of densely packed J-aggregates in a polymeric matrix, in which the matrix mimics a protein scaffold. This library of organic materials shows polaritonic properties which can be tuned from the visible to the infrared by choice of the model molecule. Inspired by the molecular architecture of the light-harvesting complexes of \textit{Rhodospirillum molischianum} bacteria, we study the light-matter interactions of J-aggregate-based nanorings with similar dimensions to the analogous natural nanoscale architectures. Electromagnetic simulations show that these nanorings of J-aggregates can act as resonators, with subwavelength confinement of light while concentrating the electric field in specific regions. These results open the door to bio-inspired building blocks for all-organic metamaterials while offering a new perspective on light-matter interactions at the nanoscale in densely packed organic matter in biological organisms including photosynthetic organelles.