【摘要】 提出一种基于光敏半导体的多功能超表面，该超表面具有双峰吸收、宽频和双频极化转换3种模式.在没有泵浦光照射时，超表面工作在双峰吸收模式，在2.25 THz和2.75 THz两个峰处的吸收率分别为95.1%和94.4%;当超表面处于1 550 nm泵浦光照射条件下，可工作在宽频极化转换模式，在1.32 THz～2.15 THz频段的极化转换率达到90%以上，相对带宽为47.8%;当超表面处于800 nm泵浦光照射条件下，超表面工作于双频极化转换模式，在1.09 THz～1.23 THz和2.12 THz～2.23 THz两个频段的极化转换率均超过90%.此外，通过分析磁场和表面电流分布，解释了不同工作模式的物理机制.本文所提出的超表面有望应用于未来的多功能太赫兹设备.更多还原

【Abstract】 In this paper, a multifunctional metasurface based on photosensitive semiconductors is proposed, which can exhibit three functions of absorption/polarization conversions. Without pump light illumination, the metasurface operates in dual-band absorption mode with the absorptivities of 95.1% and 94.4% at 2.25 THz and 2.75 THz, respectively. When the metasurface is illuminated by the 1 550 nm pump light, it works in broadband polarization conversion mode with the polarization conversion rate(PCR) of above 90% and the relative bandwidth of 47.8% in 1.32 THz～2.15 THz frequency band. When the metasurface is illuminated by the 800 nm pump light, it works in dual-band polarization conversion mode with the PCRs of over 90% in two bands of 1.09 THz～1.23 THz and 2.12 THz～2.23 THz. The physical mechanism of different modes is explained by analyzing the magnetic field and surface current distributions. The proposed metasurface may be useful in future multifunctional terahertz devices.更多还原