Li Wen-Di, Hu Jonathan, Chou Stephen Y
NanoStructures Laboratory, Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA.
Opt Express. 2011 Oct 10;19(21):21098-108. doi: 10.1364/OE.19.021098.
We observed that when subwavelength-sized holes in an optically opaque metal film are completely covered by opaque metal disks larger than the holes, the light transmission through the holes is not reduced, but rather enhanced. Particularly we report (i) the observation of light transmission through the holes blocked by the metal disks up to 70% larger than the unblocked holes; (ii) the observation of tuning the light transmission by varying the coupling strength between the blocking disks and the hole array, or by changing the size of the disks and holes; (iii) the observation and simulation that the metal disk blocker can improve light coupling from free space to a subwavelength hole; and (iv) the simulation that shows the light transmission through subwavelength holes can be enhanced, even though the gap between the disk and the metal film is partially connected with a metal. We believe these finding should have broad and significant impacts and applications to optical systems in many fields.
我们观察到，当光学不透明金属膜中的亚波长尺寸孔洞被比孔洞大的不透明金属圆盘完全覆盖时，透过孔洞的光传输并未降低，反而增强了。特别地，我们报告了：（i）观察到透过被金属圆盘阻挡的孔洞的光传输，这些圆盘比未被阻挡的孔洞大70%；（ii）观察到通过改变阻挡圆盘与孔洞阵列之间的耦合强度，或通过改变圆盘和孔洞的尺寸来调节光传输；（iii）观察和模拟表明金属圆盘阻挡器可改善从自由空间到亚波长孔洞的光耦合；以及（iv）模拟显示即使圆盘与金属膜之间的间隙部分与金属相连，透过亚波长孔洞的光传输仍可增强。我们相信这些发现将对许多领域的光学系统产生广泛而重大的影响和应用。
