Manipulations of Optical Resonances from Visible to Near-IR Based on a-Si Elliptic Nanopillar Arrays

A polarization dependent amorphous silicon (a-Si) subwavelength elliptic nanopillars array is studied. By manipulating the parameters of units and polarization states of incident plane wave, the characteristics of optical resonances from visible to near-IR are investigated. Multipole decomposition method is used to formulate the multipoles’ contribution to the formation of resonance. After fabricating arrays with electron beam lithography (EBL), the transmission spectrum of arrays is measured and found to be consistent with the simulation results. Based on the properties of the multipoles to modulate the parameters of the array, resonance features can be predicted and fabricating-friendly nanodevices can be realized. The array is arising new interest in applications such as biosensing, optical filtering and magneto-optical enhancement.