Kim Sangsik, Xuan Yi, Drachev Vladimir P, Varghese Leo T, Fan Li, Qi Minghao, Webb Kevin J
School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA.
Opt Express. 2013 Jul 1;21(13):15081-9. doi: 10.1364/OE.21.015081.
We demonstrate high resonant absorption of visible light with a plasmonic nanocavity chain structure fabricated through resistless nanoimprinting in metal (RNIM). The RNIM approach provides a simple, reproducible, and accurate means to fabricate metallic nanopatterns with high fidelity. The nanocavities are shown to be efficiently excited using normally incident light, and the resonant wavelength can be controlled by either the width or the depth of the cavity. Numerical simulations confirm the experimental observations, and illustrate the behavior of the nanocavity chain waveguide and insensitivity to incident angle. The resonant absorption is due to the excitation of a localized metal-insulator-metal cavity mode. The interacting surface waves allow cavity lengths on the order of ten nanometers for light having a free space wavelength of about four hundred nanometers. Coupling of the cavities with an intervening surface plasmon wave results in a collective excitation and a chain waveguide mode that should prove valuable for more sensitive detection based on surface enhanced Raman scattering.
我们展示了通过在金属中进行无抗蚀剂纳米压印（RNIM）制造的等离子体纳米腔链结构对可见光的高共振吸收。RNIM方法提供了一种简单、可重复且准确的手段来制造具有高保真度的金属纳米图案。结果表明，使用垂直入射光可以有效地激发纳米腔，并且共振波长可以通过腔的宽度或深度来控制。数值模拟证实了实验观察结果，并说明了纳米腔链波导的行为以及对入射角的不敏感性。共振吸收是由于局部金属-绝缘体-金属腔模式的激发。相互作用的表面波允许对于具有约四百纳米自由空间波长的光，腔长度达到十纳米量级。腔与中间表面等离子体波的耦合导致集体激发和链波导模式，这对于基于表面增强拉曼散射的更灵敏检测应该是有价值的。
