利用三维时域有限差分(3D-FDTD)方法，研究了具有周期性亚波长鱼形孔阵列微纳结构金属膜的光学透射特性，探讨了单元尺寸和孔的形状对这种结构的基于透射的光学滤波特性的影响。结果显示鱼形孔阵列金属微结构具有较高的透射效率，并且具有较高的滤波品质因子。通过分析电场分布图，揭示了这种透射的两种不同物理机制：局域波导共振模式和表面等离波子共振模式。两种共振模式在鱼形孔区域的不同位置、不同时刻以不同形式出现。

We numerically studied the enhancement of optical transmission through the periodic arrays of fish-shaped nano structure metallic arrays by using the three-dimensional finite-difference time-domain (3D-FDTD) method, and investigate the influence of lattice constant and hole shape on the optical filtering properties，which is based on transmission. Results show that fish-shaped metallic nano structure has the properties of high transmission efficiency and high filtering quality factor. It is revealed by analyzing the maps of electric-field distribution that optical transmission originates from two different physical mechanisms: localized waveguide resonance mode and surface plasmon resonance mode. Two resonance modes arise in different places in fish-shaped hole region at different time with different forms.