A High Quality-Factor Optical Modulator with Hybrid Graphene-Dielectric Metasurface Based on the Quasi-Bound States in the Continuum

Chaolong Li; Hongbo Cheng; Xin Luo; Ziqiang Cheng; Xiang Zhai

doi:10.3390/mi13111945

A High Quality-Factor Optical Modulator with Hybrid Graphene-Dielectric Metasurface Based on the Quasi-Bound States in the Continuum

Micromachines (Basel). 2022 Nov 10;13(11):1945. doi: 10.3390/mi13111945.

Authors

Chaolong Li¹, Hongbo Cheng², Xin Luo^{1

3}, Ziqiang Cheng¹, Xiang Zhai⁴

Affiliations

¹ School of Science, East China Jiaotong University, Nanchang 330013, China.
² Science and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemotechnology, Xiangyang 441003, China.
³ Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China.
⁴ Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China.

Abstract

In this paper, we combine the dielectric metasurface with monolayer graphene to realize a high quality(Q)-factor quasi-BIC-based optical modulator, and the corresponding modulation performances are investigated by using the finite-difference time-domain (FDTD) method, which can be well fitting by the Fano formula based on the temporal couple-mode theory. The results demonstrate that bound states in the continuum (BIC) will turn into the quasi-BIC with high Q-factor by breaking the symmetry of every unit of the metasurface. Meanwhile, the amplitude and bandwidth of transmission based on the quasi-BIC mode can be efficiently adjusted by changing the Fermi energy (E_F) of monolayer graphene, and the maximum difference in transmission up to 0.92 is achieved. Moreover, we also discuss the influence of the asymmetry degree to further investigate the modulation effect of graphene on the quasi-BIC mode.

Keywords: bound states in the continuum; graphene; metasurface.

Abstract

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