Wang Huan, Linghu Jiajun, Wang Xuezhi, Zhao Qiyi, Shen Hao
School of Science, Chang'an University, Xi'an 710061, China.
School of Science, Xi'an University of Posts & Telecommunications, Xi'an 710121, China.
Nanomaterials (Basel). 2023 Jun 23;13(13):1914. doi: 10.3390/nano13131914.
The coupling effects of surface plasmon resonance (SPR) from metamaterials induce variation in both the frequency and intensity of plasmonic modes. Here, we report an angular-dependent THz modulator with hybrid metal-graphene metastructures. The metastructures composed of the period gold split-rod arrays on top of a monolayer graphene, which show redshift modulation in the THz region with an increasing incident angle due to the strong out-of-plane magnetic flux introduced by the clockwise circular current at the oblique incidence. By utilizing graphene-based actively tunable conductor with ion-gel electrical gating, the THz transmission can be significantly modified. The modulation depth of the hybrid metal-graphene metastructure modulator can reach ~37.6% at 0.62 THz with a gate voltage of -3 V. The theoretical modeling of transmitted dependency on frequency and incident angle is demonstrated at different Fermi energies, which fits well with the experimental results. This hybrid device can offer a useful method for THz applications (such as angle sensors or angular-resolved spectroscopy), where angle-dependent modulation is needed.
超材料的表面等离子体共振（SPR）耦合效应会引起等离子体模式的频率和强度变化。在此，我们报道了一种具有混合金属 - 石墨烯异质结构的角度依赖型太赫兹调制器。该异质结构由单层石墨烯顶部的周期性金裂环阵列组成，由于斜入射时顺时针圆形电流引入的强面外磁通量，在太赫兹区域随着入射角增加呈现红移调制。通过利用基于石墨烯的具有离子凝胶电门控的有源可调导体，可以显著改变太赫兹传输。在 - 3 V 的栅极电压下，混合金属 - 石墨烯异质结构调制器在 0.62 THz 时的调制深度可达约 37.6%。在不同费米能量下展示了传输对频率和入射角依赖性的理论建模，其与实验结果吻合良好。这种混合器件可为需要角度依赖调制的太赫兹应用（如角度传感器或角分辨光谱）提供一种有用的方法。
