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Julia F. M. Werra

Publications and source records attributed to Julia F. M. Werra.

2 recordsLinked to original sources

Fluorescence enhancement by dark plasmon modes

We investigate the fluorescence properties of colloidal quantum dots attached to gold rod nanoantennas. These structures are fabricated by a two step electron beam lithography process in combination with a chemical linking method. By varying the nanoantenna length, the plasmon modes of the nanoantennas are successively tuned through the emission band of the quantum dots. We observe a pronounced fluorescence enhancement both for short and long nanoantennas. These findings can be attributed to the coupling of the quantum dots to bright and dark plasmon modes, respectively.

physics.optics↗

TE resonances in graphene-dielectric structures

We investigate the dispersion relations of TE resonances in different graphene-dielectric structures. Previous work has shown that when a graphene layer is brought into contact with a dielectric material, a gap can appear in its electric band structure. This allows for the formation of TE-plasmons with unusual dispersion relations. In addition, if the dielectric has a finite thickness, graphene strongly modifies the behavior of the waveguiding modes by introducing dissipation above a well-defined cutoff frequency thus providing the possibility of mode filtering. This cutoff and the properties of TE-plasmons are closely related to the pair-creation threshold of graphene thus representing quantum mechanical effects that manifest themselves in the electromagnetic response.

physics.optics↗