Abstract. A terahertz graphene tunable absorber consisting of monolayer graphene on a dielectric grating and a substrate separated by a waveguide layer is designed and investigated. The absorber exhibits polarization-independent absorption enhancement at resonance for fully conical light incidence, which is attributed to the simultaneous excitation of two identical guided modes in the waveguide layer. Moreover, the absorber possesses an ultranarrow absorption profile with an ultrahigh quality factor. To intuitively confirm the potential physical mechanism of such phenomena, the electromagnetic field distributions for both polarized light are described. Finally, the influences of Fermi level and relaxation time on the absorption properties are investigated, which present the flexible tunability of the proposed device. It is believed that the conclusions will enable the development of optoelectronic devices by simply combining graphene with a guided-mode resonance structure.

中文翻译：

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石墨烯中与偏振无关的吸收增强用于锥形安装中的光入射

摘要。设计并研究了一种太赫兹石墨烯可调吸收器，该吸收器由介电光栅上的单层石墨烯和由波导层分隔的基板组成。对于完全锥形光入射，吸收器在共振时表现出与偏振无关的吸收增强，这归因于波导层中两个相同导模的同时激发。此外，吸收体具有超窄吸收曲线和超高品质因数。为了直观地确认这种现象的潜在物理机制，描述了两种偏振光的电磁场分布。最后，研究了费米能级和弛豫时间对吸收特性的影响，这展示了所提出的器件的灵活可调性。