Birck Nanotechnology Center, School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA.
Sensors (Basel). 2011;11(7):7178-87. doi: 10.3390/s110707178. Epub 2011 Jul 13.
Nanostructured plasmonic metamaterials, including optical nanoantenna arrays, are important for advanced optical sensing and imaging applications including surface-enhanced fluorescence, chemiluminescence, and Raman scattering. Although designs typically use ideally smooth geometries, realistic nanoantennas have nonzero roughness, which typically results in a modified enhancement factor that should be involved in their design. Herein we aim to treat roughness by introducing a realistic roughened geometry into the finite element (FE) model. Even if the roughness does not result in significant loss, it does result in a spectral shift and inhomogeneous broadening of the resonance, which could be critical when fitting the FE simulations of plasmonic nanoantennas to experiments. Moreover, the proposed approach could be applied to any model, whether mechanical, acoustic, electromagnetic, thermal, etc, in order to simulate a given roughness-generated physical phenomenon.
纳米结构等离子体超材料，包括光学纳米天线阵列，对于先进的光学传感和成像应用非常重要，包括表面增强荧光、化学发光和拉曼散射。尽管设计通常使用理想的光滑几何形状，但实际的纳米天线具有非零粗糙度，这通常会导致增强因子发生变化，因此在设计中应该考虑到这一点。在这里，我们旨在通过将真实的粗糙几何形状引入有限元（FE）模型来处理粗糙度。即使粗糙度不会导致明显的损耗，它也会导致共振的光谱移动和非均匀展宽，这在将等离子体纳米天线的 FE 模拟拟合到实验时可能是关键的。此外，所提出的方法可以应用于任何模型，无论是机械的、声学的、电磁的、热的等，以模拟给定的由粗糙度引起的物理现象。
