色散金属光学特性分析通用时域有限差分方法

结合数字信号处理中的半解析递归卷积(SARC)算法,提出一种用于金属光学特性分析的改进半解析递归时域有限差分方法(SARC FDTD)。该方法保持了SARC算法的绝对稳定性和高精度、低内存等优点,又利用梯形近似使FDTD递推公式更加简洁,计算效率进一步提高,对于各种常用金属色散模型,均只需给出模型的极点和对应的系数,即可运用该算法的程序进行计算,具有较好的通用性。最后,通过金属的高阶Lorentz,Drude-Lorentz和Drude-CP三种常用色散模型对算法进行了验证。

Unified finite-difference time-domain approach for analysis of optical characteristics of dispersive metals

An improved finite-difference time-domain (FDTD) method with the semi-analytical recursive convolution (SARC) algorithm in digital signal processing (DSP) techniques for analysis of optical characteristics of the dispersive metals is presented. In this method, the absolute stability, high accuracy and low storage of the original SARC FDTD in dealing with general dispersive media is retained, while a concise update formula with increasing computational efficiency is presented by introducing the trapezoidal approximation. The proposed SARC FDTD approach can therefore be applied to the analysis of optical characteristics of metals provided the pole and corresponding coefficients in the metal dispersion model of interest are given. Three typical kinds of dispersive model for the metals, i.e. multi-poles Lorentz, Drude-Lorentz and Drude-CP are tested to demonstrate the feasibility of the present scheme.