Optical transmission properties of a single subwavelength aperture in a real metal
Optical transmission properties of a single subwavelength aperture in a real metal
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DOI：
10.1016/j.optcom.2004.05.058
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发表时间：
2004-09-01
影响因子：
2.4
通讯作者：
Ebbesen, TW
中科院分区：
文献类型：
--
作者：
Degiron, A;Lezec, HJ;Ebbesen, TW
亚波长光阑是近场光学器件和许多现代光子学结构中的关键元件。当这种孔的横向尺寸小于波长的一半时，光不能通过孔传播，并且透射通常非常弱。通常认为它是孔径直径的四次方，这个结果首先由Bethe [Phys. Rev. 66（1944）163]在1944年通过分析通过无限薄的完美金属屏幕上的小孔的透射率而提出。然而，真实的亚波长孔径是非常不同的，因为金属的厚度和有限的电导率具有远未被很好地理解的显著后果。在这里，我们报告说，光撞击在孤立的亚波长孔在真实的金属膜，在这种情况下银，激发局部表面等离子体模式的孔径脊。它们的激活引起具有意想不到的增强的透射峰和方向性的光学隧穿。这些属性遵循LSP模式的偶极性质，并且可以通过孔径形状的适当设计来调谐。这些发现与亚波长光学的当前趋势有关。(C)2004 Elsevier B.V.保留所有权利。
A subwavelength aperture is a key element in near-field optical devices and many recent photonic structures. When the lateral dimensions of such aperture is smaller than half the wavelength, light cannot propagate through the hole and the transmission is typically very weak. It is usually believed to scale as the fourth power of the aperture diameter, a result first stated by Bethe [Phys. Rev. 66 (1944) 163] in 1944 by analyzing the transmission through a small hole in an infinitely thin perfectly metal screen. However, a real subwavelength aperture is very different because the thickness and the finite conductivity of the metal has significant consequences which are far from being well understood. Here we report that light impinging on isolated subwavelength holes in real metal film, in this case Ag, excite localized surface plasmon modes on the aperture ridge. Their activation gives rise to optical tunneling with unexpected enhanced transmission peaks and directionality. These properties follow from the dipolar nature of the LSP modes and can be tuned by an appropriate design of the aperture shape. These findings are of relevance for the current trends in subwavelength Optics. (C) 2004 Elsevier B.V. All rights reserved.