High sensitivity and large field enhancement of symmetry broken Au nanorings: effect of multipolar plasmon resonance and propagation

The multipolar plasmon resonance and propagation of Au nanorings with symmetry broken were analyzed by using DDA and FDTD methods. Based on the multipolar plasmon resonance and propagation, we proposed ring-nanosensors with high sensitivities and optical ringnanoantennas with large local field enhancements. We revealed that the refractive index sensitivities of split nanorings are about 100% larger than those of perfect nanorings with same size; the local field intensity enhancement of split nanoring with three gaps has increased by 37% than that of dipole antennas.