Macromolecular Chemistry and Molecular Materials

The research interests of apl. Prof. Dr. Thomas Fuhrmann-Lieker (Macromolecular Chemistry and Molecular Materials) comprise self-organization phenomena and photonics of soft matter. Recent projects that are highlighted here focus on random lasing and photonic functionalization in microalgae.

Lasing in disordered materials (Focus Topic Photonics)

Based on our experience on Amplified Spontaneous Emission and Distributed Feedback Lasing in organic glasses we extended the range of resonators to disordered systems. Random lasing with narrow mode bandwidths of <0.1 nm have been achieved in wrinkled systems in which the emissive layer is placed between a rigid substrate and a cladding. When heated to the glass transition of the central layer, the resulting wrinkles provide the necessary feedback for random laser modes (Fig 1, left) when pumped with a nitrogen laser. Stimulated emission was also achieved in plain copy paper or calligraphy paper stained with fluorescent brightening agents (Fig. 1, right). Dyes applied by commercial highlighter pens shift the sharp emission line to various colors.

Figure 1. Left: upper row: Formation of wrinkles by relaxation of stressed layer systems; lower row: resulting morphology and emission modes upon photoexcitation; right: emission spectrum and morphology of dye-stained paper fibers

Highlight publication: N. Hoinka, T. Fuhrmann-Lieker, "Amplified Spontaneous Emission in Paper", Scientific Reports 9, 1862 (2019)

Selforganization of biominerals in space and time (Focus Topic 3D-Nanostructures)

Having worked on the photonic properties of diatoms (Bacillariophyta) for a long time, our focus is now directed to the spatiotemporal processes that govern the reproduction of diatoms. As part of the graduate school on „Biological clocks“ we investigate the inheritance of the disordered pattern in the generation cycle; as part of the research group PhosMORg we investigate the role of highly phosphorylated biopolymers in pattern formation (Fig. 2). As tool for detecting ageing in synchro­nized algae cultures, in-vivo-staining is applied. By simultaneous staining with two different dyes, Förster-type energy transfer has been demonstrated, which allows the calculation of mean staining density in the silica biomineral.

Figure 2. Biological and chemical views on the spatiotemporal organization of the diatom cell wall. Patterns that arise are interesting for their active and passive photonic properties, the latter being accessible via staining with laser dyes

Highlight publication: M. Grimann, T. Fuhrmann-Lieker, "Simultaneous uptake of a Förster transfer dye pair by diatoms: Application in determination of staining density", J. Photochem. Photobiol. B: Biol. 163, 105 (2016)

Office

Martina Otto

Telephone:    +49 561 804-4605
Telefax:         +49 561 804-4555

martina.otto[at]uni-kassel[dot]de