A hybrid plasmonic absorber consisting of graphene and silica layers coated on a metal film with concentric-rings grooves is presented and numerically investigated in this paper. The proposed structure provides two absorption peaks at near-infrared region. The absorptivity of each peak can be tuned independently, by controlling the chemical potential of the graphene layer. Modulation of absorption per graphene Fermi energy about $85\%\text{/eV}$and $51.25\%\text{/eV}$ can be obtained for the first and the second peaks, respectively. Simulation results also indicate that the absorption magnitudes of the peaks are independent of the polarization of the incident light. Hence, the proposed device can be utilized as a polarization insensitive optical modulator with two independently tunable bands. It is also shown that by splitting the silica filled rings (in this case, some parts of the silica inside the grooves are replaced by silver.), more individual peaks are appeared in the absorption spectrum of the device, whose absorptivity are dependent directly upon the positions of the silver gaps. Hence, the proposed device is a tunable light absorber with fully controllable absorption spectrum that can be used in a wide range of applications from photo-detectors to multi spectral tunable reflectors

提出了一种混合等离子体激元吸收体，该复合等离子体吸收体由石墨烯和二氧化硅层组成，并涂覆在具有同心环凹槽的金属膜上，并进行了数值研究。所提出的结构在近红外区域提供两个吸收峰。通过控制石墨烯层的化学势，可以独立地调整每个峰的吸收率。每个石墨烯费米能量的吸收调制约为$85％\text{/ eV}$和 $51.25％\text{/ eV}$分别针对第一峰和第二峰获得。仿真结果还表明，峰的吸收幅度与入射光的偏振无关。因此，所提出的设备可以用作具有两个独立可调频带的偏振不敏感光学调制器。还显示出，通过将二氧化硅填充的环分开（在这种情况下，凹槽内的二氧化硅的某些部分被银代替），在器件的吸收光谱中会出现更多的单个峰，其吸收率直接取决于银缺口的位置。因此，所提出的装置是具有完全可控的吸收光谱的可调光吸收器，其可以在从光电探测器到多光谱可调反射器的广泛应用中使用。