微结构金属膜环带片电磁聚焦优化设计方法

微结构金属膜环带片是一类新颖的微纳光子学元件,应用于超分辨光学聚焦、纳米显微成像、精密工程测量等。阐述了微结构金属膜环带片的通用、快速矢量优化设计方法,适用于线偏振光、圆偏振光、径向偏振光等典型矢量光束,可调制产生远场超分辨聚焦光斑和超细光针场。基于三维时域有限差分法进行了微结构金属膜环带片的严格电磁理论验证,能够精确模拟光场在微结构金属膜环带沟槽内部的散射传播过程。在深紫外至可见光波段,给出了λ/10～λ/6厚金属铝膜制备微结构环带片的经验选取方法。

Optimization Design Method for Electromagnetic Focusing Micro-structured Metallic-film Multi-annular Plates

Micro-structured metallic-film multi-annular plate (MAP) is one kind of novel micro-/nanophotonic element, which can be applied in the fields of super-resolution optical focusing, nanoscopic imaging, and precision engineering measurement. A versatile, fast, vectorial optimization design method for MAP is described for modulating far-field super-resolution focusing spots and ultra-thin optical needles. It is applicable for a variety of vector beams such as linearly, circularly, and radially polarized beams. Rigorous electromagnetic validation method for MAP is established based on the three-dimensional finite-difference time-domain method, which accurately models the scattering process of light propagating within micro-structured metallic annular grooves. For light wavelengths ranging from deep ultra-violet to visible, an empirical selection rule of the metallic coating film for MAP is the aluminum film at a thickness within λ/10～λ/6.