设计了一种基于光敏材料硅(Si)的宽频带极化不敏感的光驱动可调谐太赫兹超材料吸波器(metamaterial absorber, 简称MMA).该可调谐太赫兹MMA基本单元结构由嵌入光敏硅的紧凑开缝环谐振器结构、中间介质隔离层与金属底板构成.硅的电导率随着入射光的强度而发生改变, 从而使太赫兹MMA工作频率和吸波性能得到有效的调节.数值计算结果表明: 当硅电导率在1.0×103 S/m到5.0×105 S/m范围内动态调节时, 该MMA吸波特性在0442 THz到0.852 THz范围内动态调节.另外, 其相对调节带宽达到63.37%, 吸收率调制深度达到60.22%.进一步的数值计算结果表明我们所设计的MMA具备极化不敏感和宽入射角的特性.

A photo-excited and polarization insensitive broadband tunable terahertz metamaterial absorber (MMA) based on the photo-sensitive material of silicon (Si) is proposed. The unit-cell structure of this MMA is consisting of compact split-ring resonator structure filled with silicon, mediate medium layer and metal ground-plane. The working frequency and absorption intensity of this terahertz MMA could be effectively tuned, when the conductivity of silicon was changed by the varied incident optical intensity. The simulation results demonstrate that this MMA is dynamically adjusted in the frequency range from 0.852 THz to 0.442 THz when the conductivity of silicon increases from 1.0×103 S/m to the 5.0×105 S/m. In addition, its relative bandwidth is as much as 63.37% and absorption modulation depth is up to 60.22%. The further simulation indicates that the MMA has characteristics of polarization insensitive and wide incident angle.