Department of Physics, University of Florida, Gainesville, Florida 32611, USA.
Opt Lett. 2010 Jul 1;35(13):2124-6. doi: 10.1364/OL.35.002124.
We measure the transmission of IR radiation through double-layer metal films with periodic arrays of subwavelength holes. When the two metal films are placed in sufficiently close proximity, two types of transmission resonances emerge. For the surface plasmon mode, the electromagnetic field is concentrated on the outer surface of the entire metallic layer stack. In contrast, for the guided mode, the field is confined to the gap between the two metal layers. Our measurements indicate that, as the two layers are laterally shifted from perfect alignment, the peak transmission frequency of the guided mode decreases significantly, while that of the surface plasmon mode remains largely unchanged, in agreement with numerical calculations.
我们测量了双层金属膜中具有亚波长周期性孔阵列的红外（IR）辐射传输。当两个金属膜放置得足够近时，会出现两种类型的传输共振。对于表面等离激元模式，电磁场集中在整个金属层堆栈的外表面上。相比之下，对于导波模式，场被限制在两层金属之间的间隙中。我们的测量表明，随着两个层从完全对准的位置横向移动，导波模式的峰值传输频率显著降低，而表面等离激元模式的峰值传输频率基本保持不变，这与数值计算结果一致。
