Serebryannikov Andriy E, Alici Kamil B, Ozbay Ekmel, Lakhtakia Akhlesh
Opt Express. 2018 Jan 8;26(1):1-14. doi: 10.1364/OE.26.000001.
Temperature-sensitive scattering of terahertz (THz) waves by infinitely long, cylindrical core-shell structures was theoretically studied. Each structure is a dielectric cylinder coated with an InSb shell illuminated by either a transverse-electric (TE) or a transverse-magnetic (TM) plane wave. InSb is a thermally tunable semiconductor showing a transition from dielectric to plasmonic state at THz frequencies. Accordingly, the total scattering efficiency (TSE) can be thermally tuned for both polarization states of the incident plane wave. The spectral locations of the maxima and minima of the TSE of an InSb-coated cylinder can be exploited for cloaking the core. At least three scenarios lead to the strong suppression of scattering by a single core-shell structure in different spectral regimes when the temperature is fixed. The excitation of localized surface-plasmon resonances is the feature being common for two of them, while the effect of volumetric resonance dominates in the third scenario. Regimes that are either highly or weakly sensitive to the core material were identified. Weak sensitivity enables masking, i.e., the core material cannot be identified by a far-zone observer. The TSE minima are usually significantly sensitive to the polarization state, but ones with weak sensitivity to the polarization state also exist.
从理论上研究了太赫兹（THz）波在无限长圆柱核壳结构上的温度敏感散射。每个结构都是一个涂有InSb壳层的介质圆柱体，由横向电场（TE）或横向磁场（TM）平面波照射。InSb是一种热可调谐半导体，在太赫兹频率下表现出从介电态到等离子体态的转变。因此，对于入射平面波的两种偏振态，总散射效率（TSE）都可以进行热调谐。InSb涂层圆柱体TSE的最大值和最小值的光谱位置可用于掩盖内核。当温度固定时，至少有三种情况会导致在不同光谱区域中单个核壳结构的散射受到强烈抑制。其中两种情况的共同特征是局域表面等离子体共振的激发，而在第三种情况中，体共振效应占主导。确定了对核心材料高度敏感或弱敏感的区域。弱敏感性使得能够进行掩蔽，即远场观察者无法识别核心材料。TSE最小值通常对偏振态非常敏感，但也存在对偏振态敏感性较弱的情况。
