结合有耗的Drude-Lorentz色散模型，提出了处理双色散模型的辛时域有限差分算法。基于矩阵分裂，辛传播算子和辅助差分方程技术，结合严格而巧妙的公式推导，构建了算法框架，并给出了详细的公式推导过程。为了验证本文算法的有效性和精确性，首先计算了一维空间双色散平板的透射系数，并与解析解对比，结果较好地符合，证明了该算法是有效而精确的。然后计算了三维空间中有实际意义的银分裂环，金属银的介电参数由Drude 模型拟合。计算了该结构的透射系数，反射系数和吸收系数，得到了银分裂环的谐振频率和吸收频率，为实际实验结果提供了可供参考的计算结果。%Combined with the Lossy Drude-Lorentz dispersive model, a symplectic finite-difference time-domain (SFDTD) algorithm is proposed to deal with the double dispersive model. Based on matrix splitting, symplectic integrator prop-agator and the auxiliary differential equation (ADE) technique, with the rigorous and artful formula derivation, the algorithm is constructed, and detailed formulations are provided. Excellent agreement is achieved between the SFDTD-calculated and exact theoretical results when transmittance coefficient in simulation of double dispersive film in one dimension is calculated. As to numerical results for a more realistic structure in three dimensions, the simulation of periodic arrays of silver split-ring resonators using the Drude dispersion model are also included. The transmittance, reflectance, and absorptance of the structure are presented to test the efficiency of the proposed method. Our method can be used as an efficiency simulation tool for checking the experimental data.
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