【摘要】 为了节省时域有限差分(FDTD)法的计算时间,提出了许多将FDTD的时域结果转换到频域的方法.文中介绍了一种基于Baker算法的Pad啨近似,并展示了其在光子晶体模拟中的应用.对频率为160THz,品质因子为5000的简单谐振子,结果显示Pad啨近似用28时间步数据得到的强度谱比快速傅里叶变换用220时间步数据得到的强度谱更精确.采用这一Pad啨近似,光子晶体平板结构中不同波矢对应的模式频率和品质因子及其能带结构可以在很短的FDTD输出结果下得出.另外,Pad啨近似也用于计算光子晶体微腔的腏狡德屎推分室蜃?更多还原

【Abstract】 To save finite-difference time-domain（FDTD） computing time,several methods are proposed to convert the time domain FDTD output into frequency domain.The Padé approximation with Baker’s algorithm and the program are introduced to simulate photonic crystal structures.For a simple pole system with frequency 160THz and quality factor of 5000,the intensity spectrum obtained by the Padé approximation from a 2⁸-item sequence output is more exact than that obtained by fast Fourier transformation from a 2²⁰-item sequence output.The mode frequencies and quality factors are calculated at different wave vectors for the photonic crystal slab from a much shorter FDTD output than that required by the FFT method,and then the band diagrams are obatined.In addition,mode frequencies and Q-factors are calculated for photonic crystal microcavity.更多还原