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| 金属-石墨烯天线的太赫兹场局域增强理论研究 |
| Localization and enhancement of terahertz electric field in metal-graphene dipole antennas |
| 投稿时间：2025-01-17 |
| DOI：10.3969/j.issn.1005-5630.202501170009 |
| 中文关键词: 石墨烯 太赫兹 光学天线 表面等离激元 偶极共振 |
| 英文关键词:graphene terahertz optical antenna surface plasmon polariton dipole resonance |
| 基金项目:国家重点研发计划（2023YFF0719200）；国家自然科学基金 （61988102） |
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| 中文摘要: |
| 石墨烯因其极高的载流子迁移率、太赫兹全光谱吸收和极快的响应速度在太赫兹探测器领域引起了科研人员的极大兴趣。太赫兹场的亚波长局域增强用于提高太赫兹-石墨烯相互作用强度，这对于提高石墨烯太赫兹探测器的性能至关重要。设计了一种金属-石墨烯复合光学天线结构，将自由空间的太赫兹场限制在亚波长尺度内，从而实现石墨烯对入射太赫兹波更高效的吸收。在太赫兹频段，所设计的结构具有两种谐振机制：表面等离激元（surface plasmon polaritions，SPPs）共振和偶极天线开路共振。从理论上探究了金属-石墨烯复合天线的耦合模式、共振频率及其随结构参数的变化。通过调节金属天线尺寸观察到偶极共振与石墨烯SPPs相遇、交错以及分离的动态耦合过程，当两者相遇时可将石墨烯的吸收增强至31%。最后，探究了不同的石墨烯费米能级与散射时间对偶极共振与SPPs之间相互作用的影响。此项研究为提高石墨烯在太赫兹波段的吸收性能提供了新的思路。 |
| 英文摘要: |
| Graphene has garnered significant attention from researchers in the field of terahertz detection, attributed to its exceptionally high carrier mobility, full-spectrum terahertz absorption, and remarkably fast response speed. The subwavelength localized enhancement of the terahertz field is employed to intensify the terahertz-graphene interaction. Such enhancement is critical for enhancing the performance of graphene terahertz detectors. A metal-graphene composite optical antenna structure was designed to confine the terahertz field in free space to the subwavelength scale, thereby enhancing the absorption of incident terahertz waves by graphene. In the terahertz band, the designed structure exhibits two resonance mechanisms, surface plasmon polaritons (SPPs) resonance and dipole antenna open-circuit resonance. The coupling mode, resonance frequency, and its variation with structural parameters of the metal-graphene composite antenna were theoretically investigated. The dynamic coupling process in which dipole resonance meets, intersects, and separates from graphene SPPs is observed by adjusting the size of the metal antenna, and the absorption of graphene can be enhanced up to 31% when the two meet. Finally, the effects of different graphene Fermi energy levels and scattering times on the interaction between the dipole resonance and SPPs are also explored. This study provides new ideas to improve the absorption performance of graphene in the terahertz band. |
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