Vu Thi Dung, Ohno Takazumi, Yamamoto Naoki, Sannomiya Takumi
Department of Materials Science and Engineering, School of Materials and Chemical Technologies, Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8503, Japan.
J Chem Phys. 2020 Feb 21;152(7):074707. doi: 10.1063/1.5131698.
Plasmonic nanoholes have attracted significant attention among nanoplasmonic devices, especially as biosensing platforms, where nanohole arrays can efficiently enhance and confine the electromagnetic field through surface plasmon polaritons, providing a sensitive detection. In nanohole arrays, the optical resonances are typically determined by the inter-hole distance or periodicity with respect to the surface plasmon wavelength. However, for short-range ordered (SRO) arrays, the inter-hole distance varies locally, so the plasmon resonance changes. In this study, we investigate the local resonance of SRO nanoholes using a cathodoluminescence technique and compare it with hexagonally ordered nanoholes. The cathodoluminescence photon maps and resonance peak analysis reveal that the electric fields are confined at the edges of holes and that their resonances are determined by inter-hole distances as well as by their distributions. This demonstrates the Anderson localization of the electromagnetic waves showing locally enhanced electromagnetic local density of states in SRO nanoholes.
等离子体纳米孔在纳米等离子体器件中引起了广泛关注，尤其是作为生物传感平台，在该平台中，纳米孔阵列可以通过表面等离子体激元有效地增强和限制电磁场，从而实现灵敏检测。在纳米孔阵列中，光学共振通常由相对于表面等离子体波长的孔间距或周期性决定。然而，对于短程有序（SRO）阵列，孔间距会局部变化，因此等离子体共振也会改变。在本研究中，我们使用阴极发光技术研究了SRO纳米孔的局部共振，并将其与六边形有序纳米孔进行了比较。阴极发光光子图和共振峰分析表明，电场被限制在孔的边缘，并且它们的共振由孔间距及其分布决定。这证明了电磁波的安德森局域化，表明SRO纳米孔中存在局部增强的电磁局域态密度。
