Spoof plasmons mimic noble metal plasmons. The equivalent of the plasma frequency is an energy scale imposed by the geometry of the metal grating upon which they propagate. In this paper we show that the dispersion of spoof plasmons in the THz can be controlled placing a doped graphene sheet on the proximity of a metallic grating, adding more versatility to this type of system. We develop a semianalytical model, based on a perfect-metal diffraction grating. This model allows to reproduce well FDTD calculations for the same problem but with much less computer time. We discuss the optical properties of the system covering a spectral range spanning the interval from the THz to the mid-IR. It is shown that the system can be used as both a perfect absorber and a sensing device. For illustrating the latter property, we have chosen different alcohols as analytes. The frequency at which perfect absorption appears can be controlled by the geometric parameters of the grating and by the value of the Fermi energy in graphene. The theoretical results predicted throughout this work can be verified experimentally in the future.

中文翻译：

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使用石墨烯表面等离激元控制金属光栅中的欺骗性等离激元

欺骗等离激元模仿贵金属等离激元。等离子频率是由它们在其上传播的金属光栅的几何形状所强加的能级。在本文中，我们表明可以控制在THz内的欺骗等离子体激元的分散，将掺杂的石墨烯片放置在金属光栅的附近，从而为此类系统增加了多功能性。我们基于完美金属衍射光栅开发了一个半分析模型。该模型允许针对相同问题重现FDTD计算结果，但计算机时间要少得多。我们讨论了涵盖从THz到中红外的区间的光谱范围的系统的光学特性。结果表明，该系统既可以用作理想的吸收器，又可以用作传感装置。为了说明后者的属性，我们选择了不同的醇作为分析物。出现完美吸收的频率可以通过光栅的几何参数和石墨烯中的费米能值来控制。整个工作中预测的理论结果可以在将来进行实验验证。