MIE RESONANCE BASED DIELECTRIC NANO CYLINDERS

Abstract

Based on Maxwell‟s equations and Mie theory, strong subwavelength artificial magnetic and electric dipole resonances can be excited within dielectric resonators and their resonant frequencies can be tailored simply by scaling the size of the dielectric resonators. This work is based on Mie resonance in dielectric nano cylinders. To generalize the result, different aspect ratio (height to radius ratio) of cylinder have been simulated. It is a well-known fact that first and second resonance of dielectric particles correspond to magnetic and electric dipole terms. Interference of optically induced magnetic and electric modes in high refractive index dielectric nano particles offers unique possibility for tailoring directional scattering and engineering the flow of light. The optical properties such as reflection coefficient, scattering cross section, relative permeability and relative permittivity of silicon nano cylinders are calculated. The optical parameters mentioned above are observed by changing the aspect ratio. The wavelength corresponding to maximum scattering extinction shifts to longer wavelengths as the height of the nanoparticle is increased. The red shift is accompanied by an increase in the scattering cross section peak intensity. The impact of higher order multipoles for large nanoparticles makes the spectra complex observed. The peak position for the nano cylinders with different aspect ratio matches the resonant wavelength. This model can be used to interpret optical properties for a cylinder when its height is increased. The scattering cross section peaks are mainly because of the magnetic and electric dipole contributions. Resonance positions are conformed from the transmission coefficient graph. From the relative permittivity and permeability calculations using the s-parameter retrieval technique, the resonance positions are reconfirmed. The demonstrated properties of silicon nano cylinders could be used for the realization of dielectric metasurfaces with different functional optical properties, in the field of nanoantennas, nanolasers, photovoltaics and even in biomedicine.