Tunable Nanoscale Confinement of Energy and Resonant Edge Effect in Triangular Gold Nanoprisms

Abstract

Here we provide a simulation based on discrete dipole approximation method of the properties of surface plasmons on triangular gold nanoprisms and investigate their electric-field distribution to identify different multiple surface plasmon resonances. Near-field maps of triangle gold nanoprisms are established. Symmetric field distribution has been obtained perpendicular to the orientation of direction of incident light. We examine how their propagation can be manipulated and discuss some of the parameters that influence optical response of noble metals. Reduction of prism thickness leads to hybridization/mixing between two horizontal triangular surfaces and possibly overall enhancement of absorption cross-section of nanoparticle and shows excellent ability to adjust the resonance peaks. Field distribution mainly distributes in the triangular surface or along the edges. At platelet corners, electric field is weak, and the trend that plasmons are partially transmitted to neighboring edges is displayed. The calculation of the field enhancement also shows that the location of the field enhancement is specified by the different resonance patterns. A “bridge” zone can be found in triangular surfaces at resonance wavelength, which refers to coupling effect between different poles. This is an essential step toward a thorough understanding of plasmon resonance in nanoprisms.