The application of the subwavelength planar structure to control the propagation direction of surface plasmon polaritons (SPPs) has attracted many interests in recent years. However, the traditional unidirectional transmission devices of SPPs are limited by the low extinction ratio, narrow working band and the incapability of controlling the transmission directions. In this study, a novel SPPs unidirectional transmission device based on metallic aperture arrays of the right triangle (RT) is proposed and demonstrated by numerical simulations (finite-difference time-domain method). The maximum extinction ratio of the unidirectional transmission device can reach upto 33 dB under the irradiation of linearly polarized light, and the device possesses a wide operating band ([Formula: see text] nm) while the extinction ratio is greater than 10 dB. Moreover, the transmission direction of SPPs can be flexibly controlled by tuning the polarization of the incident beam. This broadband, polarization-mediated and high extinction ratio unidirectional transmission device shows great potential in the compact plasmonic devices.

中文翻译：

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基于金属三角形孔径阵列的宽带和偏振介导的单向等离子体激元发射

近年来，利用亚波长平面结构控制表面等离子激元（SPPs）的传播方向引起了很多兴趣。然而，传统的SPP单向传输装置存在消光比低、工作频带窄、无法控制传输方向等问题。在这项研究中，提出了一种基于直角三角形（RT）金属孔径阵列的新型SPP单向传输装置，并通过数值模拟（有限差分时域方法）进行了演示。该单向传输器件在线性偏振光照射下最大消光比可达33dB，器件具有较宽的工作波段（[公式：见正文]nm），消光比大于10dB。此外，可以通过调节入射光束的偏振来灵活控制 SPP 的传输方向。这种宽带、偏振介导和高消光比的单向传输器件在紧凑型等离子体器件中显示出巨大的潜力。