CaSTL Seminar by Peter Stevenson

Asymmetric dimer nanocrescents fabricated using copper mask nanosphere template lithography elicit giant circular dichroism (CD) responses. Chiro-optical activity, commonly used to distinguish between molecular chiral enantiomers, illustrates light-matter interactions that depend dramatically on plasmonic structural characteristics. Dimer nanocrescents exhibit enhanced chiro-optical activity and switches in CD handedness relative to tilt. Detailed analysis also shows these structures exhibit orientation dependent handedness and additional control in handedness is observed relative to sample rotation. In aluminum nanocrescents, the structural features of dimers are evaluated to understand gap dependency in the connecting crescent tip region and the role of this gap in CD activity. Optical activity is compared using symmetric and asymmetric plasmonic dimer nanocrescents (i.e., nominally achiral and chiral nanostructures) and their potential application in probing chemical systems is discussed.