MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi'an, 710072, China.
Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria, 3122, Australia.
Sci Rep. 2018 Jan 24;8(1):1558. doi: 10.1038/s41598-018-19869-y.
The quality (Q) factor and tunability of electromagnetically induced transparency (EIT)-like effect in plasmonic systems are restrained by the intrinsic loss and weak adjustability of metals, limiting the performance of the devices including optical sensor and storage. Exploring new schemes to realize the high Q-factor and tunable EIT-like effect is particularly significant in plasmonic systems. Here, we present an ultrahigh Q-factor and flexibly tunable EIT-like response in a novel plasmonic system. The results illustrate that the induced transparency distinctly appears when surface plasmon polaritons excited on the metal satisfy the wavevector matching condition with the guided mode in the high-refractive index (HRI) layer. The Q factor of the EIT-like spectrum can exceed 2000, which is remarkable compared to that of other plasmonic systems such as plasmonic metamaterials and waveguides. The position and lineshape of EIT-like spectrum are strongly dependent on the geometrical parameters. An EIT pair is generated in the splitting absorption spectra, which can be easily controlled by adjusting the incident angle of light. Especially, we achieve the dynamical tunability of EIT-like spectrum by changing the Fermi level of graphene inserted in the system. Our results will open a new avenue toward the plasmonic sensing, spectral shaping and switching.
在等离子体系统中，电磁感应透明（EIT）类似效应的质量（Q）因子和可调谐性受到金属固有损耗和弱可调谐性的限制，限制了包括光学传感器和存储在内的器件的性能。探索实现高 Q 因子和可调谐 EIT 类似效应的新方案在等离子体系统中尤为重要。在这里，我们提出了一种新型等离子体系统中的超高 Q 因子和灵活可调谐的 EIT 类似响应。结果表明，当表面等离激元极化激元在金属上激发时满足与高折射率（HRI）层中的导模的波矢匹配条件时，诱导透明明显出现。EIT 类似光谱的 Q 因子可超过 2000，与等离子体超材料和波导等其他等离子体系统相比，这是显著的。EIT 类似光谱的位置和线型强烈依赖于几何参数。在分裂吸收光谱中产生了 EIT 对，可以通过调整光的入射角轻松控制。特别是，我们通过改变插入系统中的石墨烯的费米能级实现了 EIT 类似光谱的动态可调谐性。我们的结果将为等离子体传感、光谱整形和切换开辟新途径。
