Highly enhanced surface plasmon resonance in a coupled silver nanodumbbell

Scattering field interactions and surface plasmon resonance in a coupled silver nanodumbbell (a pair of silver nanosphere connected by a silver nanobar) are simulated by using the three-dimensional finite-element method. The enhancement of scattering cross section which exhibits a blue-shifted is associated with the diameter of the silver nanobar and the wavelength of incident light. Interestingly, the generated optical cloud exceeds two times of the nanodumbbell size which can be turned by varying the diameter of the silver nanobar.