具有形状变化夹杂物的超材料中的时间界面
Temporal Interfaces in Metamaterials with Shape-Varying Inclusions
浏览论文内容
中文总结 AI 辅助
本研究提出解析与数值框架，证明通过改变超材料中圆柱夹杂物的几何形状（如半径或截面形状）可实现时间散射、频率转换及能量流方向控制，并预测共振区可增强时间瞄准效应。
中文摘要 AI 辅助
超材料的时间调制通常通过改变组成材料的性质来实现，而改变超原子几何形状则提供了控制其有效响应的额外手段。在此，我们开发了一个解析和数值框架，用于研究由经历突然几何变换的圆柱形夹杂物组成的超材料中的时间散射。改变圆形圆柱体的半径会改变填充分数和标量面内有效介电常数，从而实现时间反射、场放大或衰减以及频率转换。从圆形横截面到椭圆形横截面的面积保持变换引入了各向异性，产生了与角度相关的时间散射，并在保持波矢的同时重新引导能量流。我们使用有效介质理论和时间边界条件推导了这些效应，并将预测与全波时域模拟进行了比较。模拟再现了主要的散射和时间瞄准趋势，在较高介电常数对比度下，角度偏转比准静态模型预测的更大。这表明向共振区域移动可能为更强的时间瞄准提供机会。这些结果确定了夹杂物几何形状作为在时间界面控制波振幅、频率和能量流方向的手段。
英文摘要
Temporal modulation of metamaterials is commonly achieved by varying constituent material properties, while changes in meta-atom geometry offer an additional means of controlling their effective response. Here, we develop an analytical and numerical framework for temporal scattering in metamaterials composed of cylindrical inclusions undergoing abrupt geometric transformations. Changing the radius of circular cylinders modifies the filling fraction and scalar in-plane effective permittivity, enabling temporal reflection, field amplification or attenuation, and frequency conversion. An area-preserving transformation from circular to elliptical cross sections introduces anisotropy, producing angle-dependent temporal scattering and redirecting the energy flow while conserving the wavevector. We derive these effects using effective-medium theory and temporal boundary conditions and compare the predictions with full-wave time-domain simulations. The simulations reproduce the main scattering and temporal-aiming trends, with larger angular deflections than predicted by the quasistatic model at higher permittivity contrasts. This suggests that moving toward the resonant regime may offer opportunities for stronger temporal aiming. These results identify inclusion geometry as a means of controlling wave amplitude, frequency, and energy-flow direction at temporal interfaces.
发表机构
- Aalto University（阿尔托大学）
机构由 AI 辅助整理，请以论文原文为准。
