Dual-channel rainbow trapping of terahertz surface plasmon-polariton in graded metallic grating structures |
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| Authors: | Yun Shen Xiaohua Deng Jiwu Fu Guoping Wang |
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| Affiliation: | 1. Department of Physics, Nanchang University, Nanchang, Chinashenyunoptics@gmail.com;3. Institute of Space Science and Technology, Nanchang University, Nanchang, China;4. Department of Physics, Nanchang University, Nanchang, China;5. Key Laboratory of Artificial Micro- and Nano- Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, China |
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| Abstract: | We numerically show that slowing down and even stopping Terahertz waves can be achieved in a one-dimensional graded-grating-depth metal structure. Since the dispersion curves are dependent on the graded grating depths, waves of different wavelengths can be localized at different spatial positions of the structure, leading to rainbow trapping. Especially, dual-channel trapped rainbows with different modes can be realized in a single structure as two bands appear in the dispersion curve within the analyzed frequency range. In addition, due to the fact that the bands with different order modes do not overlap one another in the frequency domain, for each mode, its single-mode propagation can be available by properly choosing operation frequency. Such a phenomenon never happens for conventional dielectric or metal waveguides. |
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| Keywords: | dual-channel trapped rainbows terahertz waves different order modes |
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