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提出了一种新型的纳米级旋转共轭希腊十字型手征结构,并对该结构上下两层希腊十字的旋转角度进行了优化;数值模拟了该结构对不同频率入射波的透射和反射响应,发现透射谱在频率为145和300THz处存在两个明显的谐振点。通过对透射反射谱的反演,计算了结构的圆二色性、旋光角,得出该结构在谐振频率附近具有很强的旋光性,最大旋光角达到了95°。分析了折射率、相对介电常数、相对磁导率和手征参数,发现这一结构在谐振频率附近分别实现了左旋圆极化波和右旋圆极化波的负折射率,且进一步证明了手征结构实现负折射率的主要原因是大的手征参数。
A new type of gyroscopic Greek cross-shaped chiral structure was proposed. The rotation angles of the Greek cross at the top and bottom of the structure were optimized. The transmission and reflection responses of the structure to different incident waves were numerically simulated. The transmission spectrum was found to have two distinct resonance points at frequencies of 145 and 300 THz. The circular dichroism and rotation angle of the structure were calculated by the inversion of transmission reflection spectra. The result shows that the structure has strong optical rotation near the resonance frequency, and the maximum optical rotation angle reaches 95 °. The refractive index, relative permittivity, relative permeability and chiral parameters were analyzed. It was found that this structure respectively achieved the negative refractive indices of left-handed circularly polarized waves and right-handed circularly polarized waves near the resonant frequency, and further proved The main reason for the negative refractive index of the chiral structure is the large chiral parameter.