Mie-resonance based plasma metamaterials: analytical theory and FDTD simulation

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Abstract A plasma metamaterial is a composite structure that incorporates plasma as one of its constituents. When the characteristic dimensions of its components are smaller than the electromagnetic wavelength, a metamaterial can, to first approximation, be treated as an effective medium capable of manipulating electromagnetic waves. Metamaterials can exhibit effective permittivity and permeability values beyond those attainable in homogeneous materials, including double-negative media characterized by a negative refractive index. An overdense plasma exhibits a negative permittivity for frequencies below its plasma frequency f p . In addition, high-permittivity dielectric cylinders can exhibit Mie resonances at discrete frequencies, where the induced displacement current is maximized. Such resonances have been exploited in metamaterials to achieve an effective negative magnetic permeability. More specifically, excitation of a ceramic cylinder at a frequency slightly above its magnetic Mie resonance leads to a strongly negative effective permeability. To the best of our knowledge, Mie resonances have not yet been explored in plasma-based metamaterials. Using the finite-difference time-domain (FDTD) method, plasma metamaterials based on Mie-resonant cylinders are demonstrated to be feasible. An analytical study was first performed for the Mie resonance of a single dielectric cylinder embedded in a cold, unmagnetized, overdense plasma. FDTD simulations were used to compute transmittance, reflectance, and power dissipation through a layer of the proposed metamaterial. The emergence of a negative effective refractive index was verified. Finally, the spatial distribution of power dissipation and the impact of cylinder radius and plasma density were examined.

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