Touching Gold Nanoparticle Chain Based Plasmonic Antenna Arrays and Optical Metamaterials

The control of light-material interactions at the nanoscale requires optical elements with sizes much smaller than the wavelength of light. Plasmonic nanostructures and optical metamaterials enable drastic control and manipulation of light at such small scales. However it is quite challenging to further reduce the size of resonant elements using conventional plasmonic nanostructures. In this paper, we propose novel optical resonators that rely on the conducting plasmon mode of touching nanoparticle chains that enable significant size reduction when compared with widely used nanostripe antennas and U-shaped split-ring resonators. We employ full-field electromagnetic simulations to study the resonance mechanisms of nanoparticle chain arrays. In comparison with the nanobar plasmonic antennas, a nanoparticle chain based antenna with similar physical sizes operates at larger wavelengths, opening routes for deep subwavelength plasmonic resonators. Moreover, using nanoshell chain arrays, we demonstrate an optical resonator that is 10 times smaller than the resonance wavelength (λ/10). Similarly, nanoparticle-based split-ring resonators provide significant size reduction that could be used for smaller metamaterial and metasurface building blocks. Designing nanoparticle-based resonant elements is a promising route for achieving optical metamaterials with smoother resonance dispersion and lower optical losses. (Graph Presented).