各向异性电介质对纳米壳层结构的法诺共振调制

Adjusting Fano resonance of core-shell nanostructure with anisotropic dielectric material

法诺共振在光开关、化学或生物探测以及新型遥感装置等方面有着广泛的应用.本文根据各向异性电介质对等离激元纳米结构的散射增强或抑制特点,提出用各向异性电介质材料实现对纳米壳层结构产生的法诺共振调控.首先根据米散射理论推出纳米壳层结构产生法诺共振的一般条件.进一步分析发现,改变各向异性电介质材料的切向介电常数或径向介电常数,可以在一定范围内调制法诺共振的峰值波长、调制幅度和线型.这有利于增加法诺共振在实际应用中的灵活性.数值模拟结果验证了理论分析的正确性和可行性.

Fano resonance has broad applications in optical switching, chemical and biological tagging and in the design of ensing devices. Due to the effect of anisotropic dielectric material on scattering property of nanostructures, we propose to adjust Fano resonance of core-shell nanostructure by anisotropic dielectric material. First, the general condition of forming Fano resource with core-shell sub-wavelength structure is derived from Mie scattering theory. Analysis indicates that changing the radial or tangential component of permittivity can adjust Fano resonance by resonance wavelength, peak intensity and shape of scattering curve. This work promotes the application of Fano resonance. Numerical calculations demonstrate the feasibility of our theoretic analysis.