论文标题
单个纳米颗粒完美吸收聚焦的光束
Perfect absorption of a focused light beam by a single nanoparticle
论文作者
论文摘要
通过耗散材料吸收电磁能是最基本的电磁过程之一，其基础是大量应用问题的基础，包括感应和分子检测，雷达检测，无线功率传递和光伏电动机。当所有传入的电磁能被系统吸收而无需散射时，完美的吸收是一种特殊的机制。通常，入射能通过平面波传递到吸收系统中，因此该波的完美吸收需要无限扩展的平面结构。在这里，我们从理论上证明了带有有限量的电磁能的限制入射梁可以被基材上有限尺寸的深度亚波长散射器完美地吸收。我们通过分析求解偶极近似中的自洽散射问题，并找到入射场空间光谱的封闭形式表达以及所需的粒子的复杂极化性。所有分析预测均通过全波模拟确认。
Absorption of electromagnetic energy by a dissipative material is one of the most fundamental electromagnetic processes that underlies a plethora of applied problems, including sensing and molecular detection, radar detection, wireless power transfer, and photovoltaics. Perfect absorption is a particular regime when all of the incoming electromagnetic energy is absorbed by the system without scattering. Commonly, the incident energy is delivered to the absorbing system by a plane wave, hence perfect absorption of this wave requires an infinitely extended planar structure. Here, we demonstrate theoretically that a confined incident beam carrying a finite amount of electromagnetic energy can be perfectly absorbed by a finite size deep subwavelength scatterer on a substrate. We analytically solve the self-consistent scattering problem in the dipole approximation and find a closed-form expression for the spatial spectrum of the incident field and the required complex polarizability of the particle. All analytical predictions are confirmed with full-wave simulations.
