Numerical Study on Enhanced Line Focusing via Buried Metallic Nanowire Assisted Binary Plate

Line focusing, which collects light into a line rather than a single point, has an advantage on variable fields such as machining and imaging. The 1-dimensional metallic zone plate is one of the candidates for line focusing, which is ultra-thin and simple to fabricate. Metallic nano-slits can replace the metal blocked region to increase the efficiency, however, the efficiency and stability are still low. Therefore, this paper proposes a structure with an additional dielectric layer to protect the metallic nano-slit layer—a buried metallic wire structure—and verify the idea based on numerical simulations. Two structures are proposed. In terms of stability, a flat surface structure is proposed and a corrugated surface structure with a consistent thickness with the nano-slit is proposed which has low fabrication difficulty. The optimization of the buried wire structure and performance after applying the buried wire structure to the dual-line focusing plate is calculated by numerical simulation. Finally, it was shown that the electric field intensity was 2.13 times greater.