Laref Slimane, Cao Jiangrong, Asaduzzaman Abu, Runge Keith, Deymier Pierre, Ziolkowski Richard W, Miyawaki Mamoru, Muralidharan Krishna
Department of Material Science and Engineering, University of Arizona, 1235 E James E Roger Way, Tucson, AZ 85721, USA.
Opt Express. 2013 May 20;21(10):11827-38. doi: 10.1364/OE.21.011827.
Physical properties of materials are known to be different from the bulk at the nanometer scale. In this context, the dependence of optical properties of nanometric gold thin films with respect to film thickness is studied using density functional theory (DFT). We find that the in-plane plasma frequency of the gold thin film decreases with decreasing thickness and that the optical permittivity tensor is highly anisotropic as well as thickness dependent. Quantitative knowledge of planar metal film permittivity's thickness dependence can improve the accuracy and reliability of the designs of plasmonic devices and electromagnetic metamaterials. The strong anisotropy observed may become an alternative method of realizing indefinite media.
众所周知，材料的物理性质在纳米尺度下与体相材料不同。在此背景下，利用密度泛函理论（DFT）研究了纳米金薄膜光学性质随薄膜厚度的变化关系。我们发现，金薄膜的面内等离子体频率随厚度减小而降低，并且光学介电常数张量具有高度各向异性且与厚度有关。平面金属薄膜介电常数随厚度变化的定量知识可以提高等离子体器件和电磁超材料设计的准确性和可靠性。观察到的强各向异性可能成为实现非定域介质的一种替代方法。
