Analytical expressions for the plasmon resonance frequencies of prolate and oblate spheroids and their dependence on ellipticity have been derived, and approximate bounds on these frequencies established. These formulas may be useful in tuning the plasmon resonance within certain limits. With increasing aspect ratio, the prolate spheroid resonance is red shifted relative to a sphere with no lower limit under the assumptions of a Drude dispersion model. On the other hand, the oblate resonances are blue shifted as the spheroid becomes increasingly flat, but up to a limit.

中文翻译：

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长长形和扁形纳米球体的等离子共振光谱范围


推导了长长球体和扁球体的等离激元共振频率及其对椭圆率的依赖性的解析表达式，并建立了这些频率的近似界限。这些公式可能有助于将等离子共振调整到一定限度内。随着长径比的增加，在德鲁德色散模型的假设下，长椭球体共振相对于没有下限的球体发生红移。另一方面，随着球体变得越来越平坦，扁圆共振发生蓝移，但达到极限。