Yu Yu, Zhou Jing, Cai Qingyuan, Chu Zeshi, Deng Jie, Lu Wei, Li Zhifeng, Chen Xiaoshuang
Opt Lett. 2021 May 1;46(9):2236-2239. doi: 10.1364/OL.423674.
Dynamically tunable ultra-narrowband perfect absorbers are important to next-generation active photonic devices. A composite structure of a graphene pair and a microcavity with Bragg mirrors are proposed for this purpose. Based on the electrically controllable doping of graphene and critical coupling of the incident light, the microcavity-graphene composite structure achieves peak absorptance higher than 99.5%, a relative peak width ($\Delta \lambda /{\lambda _0}$) smaller than 1.1%, and a modulation depth larger than 92.0% throughout the visible-to-mid-infrared range, surpassing other structures in comprehensive performance. By changing the number of the dielectric pairs in the Bragg mirrors, the device can become an amplitude or a spectral modulator. The results are based on the optical constants from experiment data, including the surface conductivity of graphene with relatively low mobility, so they are more useful in practical situations.
动态可调谐超窄带完美吸收体对下一代有源光子器件至关重要。为此，提出了一种由石墨烯对和带有布拉格镜的微腔组成的复合结构。基于石墨烯的电可控掺杂和入射光的临界耦合，微腔 - 石墨烯复合结构在整个可见光到中红外范围内实现了高于99.5%的峰值吸收率、小于1.1%的相对峰值宽度（$\Delta \lambda /{\lambda _0}$）以及大于92.0%的调制深度，综合性能超越了其他结构。通过改变布拉格镜中电介质对的数量，该器件可以成为幅度或光谱调制器。这些结果基于实验数据的光学常数，包括迁移率相对较低的石墨烯的表面电导率，因此在实际应用中更具实用性。
