Porous ceramic material is widely used in a great deal of fields. In this work, porous alumina ceramics with micron open cells are modeled by applying the inverse opal structure. The considered porous alumina ceramics are periodic with different size parameters. The diameters of spherical pores are 200, 400, 600, and 800 nm, while the ratios of height to diameter range from 0.1 to 0.9. The absorptivity, transmissivity, and reflectivity for the wavelength range from 0.2 to 2 μm are calculated using the finite difference time domain (FDTD) method. Then the effects of size parameters and incident angle on the optical properties are discussed. The results show that the absorptivity is usually very small. For the transmissivity, a wide dip in the transmission spectrum appears when the diameter and height exceed the critical values, and a red shift of the transmission spectrum's wide dip with increasing height is observed. When the incident wavelength is longer than the critical wavelength, the spectral transmissivities of porous ceramics with a certain diameter reach a stable domain. Moreover, the red shift of the wide dip, the critical incident wavelength, and the critical ratio of height to diameter are visibly affected by the size parameters and the incident angle.

中文翻译：

---

微米开孔的多孔氧化铝陶瓷的光学性能

多孔陶瓷材料被广泛用于许多领域。在这项工作中，通过应用反蛋白石结构对具有微米开孔的多孔氧化铝陶瓷进行建模。所考虑的多孔氧化铝陶瓷是周期性的，具有不同的尺寸参数。球形孔的直径为200、400、600和800 nm，而高度与直径的比率为0.1到0.9。使用有限差分时域（FDTD）方法计算0.2到2μm波长范围内的吸收率，透射率和反射率。然后讨论了尺寸参数和入射角对光学性能的影响。结果表明，吸收率通常很小。对于透射率，当直径和高度超过临界值时，透射光谱会出现大幅下降，并且观察到透射光谱的宽倾角随高度增加而发生红移。当入射波长大于临界波长时，具有一定直径的多孔陶瓷的光谱透射率达到稳定范围。而且，宽倾角的红移，临界入射波长和高度与直径的临界比明显受到尺寸参数和入射角的影响。