Electrical Control of Electromagnetically Induced Transparency by Terahertz Metamaterial Funneling
Electrical Control of Electromagnetically Induced Transparency by Terahertz Metamaterial Funneling
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DOI：
10.1002/adom.201801205
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发表时间：
2019-01-18
影响因子：
9
通讯作者：
Lee, Hojin
中科院分区：
文献类型：
--
作者：
Jung, Hyunseung;Jo, Hyunwoo;Lee, Hojin
使用超材料的电磁感应透明（EIT）类似物具有多种应用，包括非线性光学、电信和生物化学传感器。这些EIT类似物可以通过将半导体材料嵌入到超材料结构中来主动控制，但大多数主动EIT超材料需要复杂的光学设置和复杂的制造工艺。基于石墨烯的EIT超材料由于其简单的电偏压可控性而成为最有前途的有源EIT系统之一，但相关研究目前仅限于理论或数值研究。在这里，通过控制独特的亚原子结构的太赫兹函数来提供实验验证的石墨烯EIT超材料。所提出的有源EIT超材料被制造在柔性和可弯曲的聚酰亚胺薄膜上，以获得最低的衬底插入损耗，并在EIT模拟的透射峰处实现1 ps的群延迟变化。此外，由于所提出的超材料表现出根据偏振方向而变化的谐振特性，因此通过将入射偏振旋转到正交方向，可以将相位延迟控制为与所提出的超材料成80度。总体而言，通过在单个超材料器件中同时控制入射波的群延迟和相位延迟，可以在太赫兹范围内实现多功能主动调谐系统。
Electromagnetically induced transparency (EIT) analogs using metamaterials have diverse applications, including nonlinear optics, telecommunications, and biochemical sensors. These EIT analogs can be actively controlled by embedding semiconducting materials into metamaterial structures, but most active EIT metamaterials require complex optical setups and complicated fabrication processes. Graphene-based EIT metamaterials are some of the most promising active EIT systems because of their simple controllability by electrical bias, but related researches have so far been limited to theoretical or numerical studies. Here, experimentally verified graphene EIT metamaterials are provided by controlling the terahertz funneling of the unique metaatom structures. The proposed active EIT metamaterials are fabricated on flexible and ultrathin polyimide films to acquire the lowest substrate insertion losses and achieve a 1 ps group delay change at the transmission peak of the EIT analog. Moreover, because the proposed metamaterials exhibit resonance properties that vary depending on the polarization direction, the phase delay can be controlled up to 80 degrees from the proposed metamaterials by rotating the incident polarization to the orthogonal direction. Overall, by controlling the group and phase delay of incident waves in a single metamaterial device simultaneously, a multifunctional active tuning system can be realized in the terahertz range.