Gong Wenqian, Shi Yiyu, Liu Zhenxing, Zhang Chi, Cui Zhiwei, Chen Yu, Zhou Xinxing
Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, School of Physics and Electronics, Hunan Normal University, Changsha 410081, China.
School of Physics, Xidian University, Xi'an, 710071, China.
Nanophotonics. 2025 Sep 5;14(19):3223-3232. doi: 10.1515/nanoph-2025-0314. eCollection 2025 Sep.
The effective medium theory (EMT) provides a simplified framework to calculate the electromagnetic responses and is generally considered exact in the all-dielectric system with deep-subwavelength constituents. In this work, we perform the Goos-Hänchen (GH) shift that invalidates the EMT on the multilayered dielectric structures under the common conditions. This breakdown of the EMT arises from the high sensitivity of the GH shift on the phase and magnitude of Fresnel reflection coefficient. The degree of such breakdown shows strong dependence on the polarization angle of incidence and the layer and filling fraction of the structures. Notably, we find that the GH shift is potentially applicable to nano-meter scale thickness sensing, which cannot be displayed based on EMT in some cases. Our findings will provide useful guidance to reduce the calculation errors of the electromagnetic responses and promote the design of precise metrology devices.
有效介质理论（EMT）提供了一个简化的框架来计算电磁响应，并且通常被认为在具有深亚波长成分的全介质系统中是精确的。在这项工作中，我们在常见条件下对多层介电结构进行了古斯-汉欣（GH）位移，这使得EMT失效。EMT的这种失效源于GH位移对菲涅耳反射系数的相位和幅度的高灵敏度。这种失效的程度强烈依赖于入射角的偏振角以及结构的层数和填充率。值得注意的是，我们发现GH位移可能适用于纳米尺度的厚度传感，在某些情况下，这是基于EMT无法实现的。我们的发现将为减少电磁响应的计算误差提供有用的指导，并促进精密计量设备的设计。
