The discovery of extraordinary optical transmission (EOT) through patterned metallic foils in the late 1990s was decisive for the development of plasmonics and cleared the path to employ small apertures for a variety of interesting applications all along the electromagnetic spectrum. However, a typical drawback often found in practical EOT structures is the large size needed to obtain high transmittance peaks. Consequently, practical EOT arrays are usually illuminated using an expanded (mimicking a plane wave) beam. Here, it is shown with numerical and experimental results in the THz range that high transmittance peaks can be obtained even with a reduced illumination spot exciting a small number of holes, provided that the structure has a sufficient number of lateral holes out of the illumination spot. These results shed more light on the prominent role of leaky waves in the underlying physics of EOT and have a direct impact on potential applications.

中文翻译：

---

小束斑的非常规太赫兹传输：泄漏波机制

在1990年代后期，通过带图案的金属箔发现了非凡的光学传输（EOT），这对等离子技术的发展具有决定性意义，并扫清了在整个电磁波谱中采用小孔径用于各种有趣应用的途径。然而，在实际的EOT结构中经常发现的典型缺陷是获得高透射率峰所需的大尺寸。因此，通常使用扩展的（模仿平面波）光束照射实际的EOT阵列。此处，通过在THz范围内的数值和实验结果表明，即使结构减少了照明点，激发了少量孔，也可以获得高透射率峰，只要该结构在照明点之外具有足够数量的侧向孔即可。 。