Large‐Area 3D Plasmonic Crescents with Tunable Chirality. Issue 15 (16th May 2019) - Goerlitzer, Eric S. A.
Abstract: Chiral plasmonic nanostructures hold promise for enhanced chiral sensing and circular dichroism spectroscopy of chiral molecules. It is therefore of interest to fabricate chiral plasmonic nanostructures with tailored chiroptical properties over large areas with reasonable effort. Here, a colloidal lithography approach is used to produce macroscopic arrays of sub‐micrometer 3D chiral plasmonic crescent structures over areas >1 cm 2 . The chirality originates from symmetry breaking by the introduction of a step within the crescent structure. This step is produced by an intermediate layer of silicon dioxide onto which the metal crescent structure is deposited. It is experimentally demonstrated that the chiroptical properties in such structures can be tailored by changing the position of the step within the crescent. These experiments are complemented by finite element simulations and the application of a multipole expansion to elucidate the physical origin of the circular dichroism of the crescent structures. Abstract : Crescent‐shaped metallic nanostructures can be fabricated over macroscopic dimensions using colloidal lithography. Using a two‐step evaporation process, a dielectric edge is integrated into the crescent architecture to break its symmetry. The optical properties of the resulting chiral crescent arrays are investigated in detail and tunable circular dichroism is demonstrated.