文摘
The enhanced optical response due to localized surface plasmons (LSPs) in interacting metallic nanostructures provides a promising avenue for the detecting small biological molecules, whereas an unconventional spectral modulation of LSPs would be obtained under the coupling of the different kinds of metallic nanostructures with nanoscale separations via small molecules. Here, we unexpectedly found an anomalous condition of light scattering from heterogeneous metallic nanostructures, i.e., silver-nanoparticle fixed bead (AgNP-FB) and gold nanorods (AuNRs) coupled via DNA, in which the light scattering dramatically suppressed in the broad UV region although it was enhanced in the visible region. Based on ultrafast computation under cluster approximation, this anomaly was attributed to the broadband cancellation of collective modes of interband transitions in AuNRs and LSPs in a single AgNP-FB. This mechanism has a high potential to apply for detection of DNA in zmol order even under white light source.
