亚波长金属聚焦透镜结构参数的优化与分析

提出同时优化亚波长金属透镜结构凹槽宽度和深度,以改善亚波长金属透镜的聚焦特性.基于有限时域差分法,详细研究了凹槽宽度和深度变化对其焦斑的峰值半宽、焦斑强度、归一化聚焦效率以及焦距的影响.通过探讨金属透镜的聚焦规律及其物理机理,给出了金属透镜的优化设计方法,为利用金属透镜实现光波的纳米聚焦及灵活操控提供了理论基础.

Optimization and analysis of the structural parameters of subwavelength metal focusing lens

The methods for improving the focusing properties of subwavelength metallic lens by optimizing the groove width and depth of the structure simultaneously are presented. We investigate how the variations of the width and depth of the groove affect the half width at half maximum of the focus, intensity, normal focusing efficiency of the focal spot and the focal length, based on the finite-difference and time-domain method. The optimum design methods of metal lens are put forth through discussing the focusing regularity and physical mechanism, which can provide a theoretical basis for realizing the nano-focusing and flexible manipulation of light wave based on metallic lens.