We propose a tunable broadband reflective cross polarization converter (CPC) composed of a graphene sheet with a T-shaped carved-hollow array. In the mid-infrared region, cross polarization conversion with 5.17 THz bandwidth is achieved due to the superimposition of the two reflection components with a phase difference of nearly 180°. The polarization conversion ratio is larger than 80% in this broadband range, and the fractional bandwidth is 40%. The physical mechanism of CPC is attributed to the excitation of symmetric and antisymmetric graphene surface plasmons. The CPC broadband can always be retained when the incident angle increases from 0° to 20°, and the polarization angle increases from 40° to 50°. Also, the tunable responses of the reflective polarizer with Fermi energy and electron scattering time are discussed. Our design can be widely applied to adjustable broadband polarization conversion.

中文翻译：

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基于带有T形雕刻空心阵列的石墨烯片的可调谐宽带交叉极化转换器

我们提出了一种可调谐的宽带反射交叉偏振转换器（CPC），该转换器由具有T形雕刻空心阵列的石墨烯片组成。在中红外区域，由于两个反射分量的相位差接近180°，因此实现了5.17 THz带宽的交叉偏振转换。在此宽带范围内，偏振转换率大于80％，分数带宽为40％。CPC的物理机制归因于对称和反对称石墨烯表面等离子体激元的激发。当入射角从0°增加到20°，并且偏振角从40°增加到50°时，CPC宽带始终可以保留。此外，还讨论了反射偏振器的费米能量和电子散射时间的可调响应。