Center for Metamaterials and Integrated Plasmonics and Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA.
Science. 2012 Aug 31;337(6098):1072-4. doi: 10.1126/science.1224823.
Metals support surface plasmons at optical wavelengths and have the ability to localize light to subwavelength regions. The field enhancements that occur in these regions set the ultimate limitations on a wide range of nonlinear and quantum optical phenomena. We found that the dominant limiting factor is not the resistive loss of the metal, but rather the intrinsic nonlocality of its dielectric response. A semiclassical model of the electronic response of a metal places strict bounds on the ultimate field enhancement. To demonstrate the accuracy of this model, we studied optical scattering from gold nanoparticles spaced a few angstroms from a gold film. The bounds derived from the models and experiments impose limitations on all nanophotonic systems.
金属在光学波长下支持表面等离激元，并且能够将光局域到亚波长区域。在这些区域中发生的场增强对各种非线性和量子光学现象设定了最终的限制。我们发现，主要的限制因素不是金属的电阻损耗，而是其介电响应的固有非局域性。金属电子响应的半经典模型对最终的场增强施加了严格的限制。为了证明该模型的准确性，我们研究了距离金膜几埃的金纳米粒子的光学散射。该模型和实验得出的限制对所有纳米光子系统都有一定的限制。
