基于棱镜耦合的金膜表面塔姆等离激元(Tamm plasmon polarition, TPP)与表面等离极化激元(surface plasmon polariton, SPP)的杂化耦合受到广泛的关注和研究，但这种传统的激发装置由于拥有体积庞大的棱镜等光学元件以及对入射光角度精准控制有严格要求，限制了其集成化发展和实际应用。为了简化TPP和SPP杂化耦合激发方式，本文提出了一种光栅耦合型多层堆叠结构设计。该结构主要包括三部分：顶部纳米厚度的金膜、中间一维布拉格光子晶体以及底部金纳米光栅。在该结构中利用底部纳米光栅的一级透射光同时实现了顶部金膜上下表面SPP和TPP共振激发。两种模式之间的耦合杂化作用极大地减少了模式的共振带宽，从而使TPP-SPP模式的传感品质因数得到了显著的提高。此外，通过改变纳米光栅的周期和组成一维布拉格光子晶体的介质层厚度，SPP和TPP可以在较宽光谱范围内实现耦合杂化。相比于传统棱镜式的TPP和SPP双模式耦合结构，设计的光栅耦合型的多层堆叠结构无需借助棱镜和对入射角精确调控，在正入射光照射下就可实现两种模式的共振耦合，这不仅易于结构的进一步集成和小型化，同时对拓宽表面等离激元传感器的实际应用具有重要的意义。
表面等离激元 杂化模式 金属纳米结构 小型化 生化传感 surface plasmon resonance hybrid mode metal nanostructure miniaturization biochemical sensing
National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Author Affiliations
Abstract
College of Physics and Optoelectrical Engineering, Dalian University of Technology, Dalian, 116023, China
Optical fiber based SPR sensors have attracted more and more attention due to their unique advantages over the prism-based SPR sensors. A novel fiber-optic SPR sensor with multi-alternating metal layers for biochemical analysis is presented in this paper. Based on the fundamental SPR theory of the fiber optic sensing technology, we theoretically investigated the effects of the existence of alternating layers deposited on sensing region SPR wavelength changes. The emphasis was placed on the numerical simulation of the fiber-optic SPR sensor’s sensitivity which could be affected by its technical parameters such as the metal thickness, number of alternating layers. Results showed that, compared to the normal SPR sensor with the single metal layer, the proposed sensor had a wider detecting range of the refractive index and higher sensitivity, which can find applications in biological analysis.
Surface plasmon resonance fiber optics biological detection alternating metal layers Photonic Sensors
2013, 3(3): 202
