球形谐振腔表面结构对银的增强辐射性能

Enhancement of radiative properties of silver by surface structure with spherical resonant cavity

研究了球形谐振腔对单质银辐射特性的影响作用,结果表明在谐振腔的谐振波长处材料的吸收率有所增加。对于良导体Ag而言,吸收率光谱呈现出窄带吸收的特性,吸收峰的位置相对于理想导体形成谐振腔的谐振波长向长波方向偏移,这是由于趋肤深度的存在使得Ag构成的谐振腔等效于一个尺寸略大的理想导体谐振腔。探讨了吸收率随球形腔体的切入深度、腔体半径、点阵周期以及入射角和极化角等的变化关系。研究表明可以通过合理设计球形腔体的结构尺寸以获得最优的窄带吸收效果,这为窄带辐射器的制作提供了一种简单有效的方法。

The influence of spherical resonant cavity on the radiative characteristics of silver was studied, and the results show that the absorptance is increased in the resonance wavelength. As for a good conductor, the absorption spectrum of silver shows the feature of narrow-band absorption. The absorption peak of the resonance wavelength was shifted to the long wavelength compared to the peak of the resonance wavelength formed by a perfect conductor. Due to the presence of skin depth, the resonant cavity was equivalent to a resonant cavity formed by a perfect conductor with a slightly larger size. With computational results, the effects of structural parameters such as the depth of the resonant cavity, the radius of the cavity, the lattice period, the incident angle and the polarization angle on the absorptance of the spherical resonant cavity were discussed. The results indicate that the optimal narrow-band absorption effect can be obtained by reasonably designing the structure size of the spherical resonant cavity and this implies an effective approach for fabricating narrow-band emitter.