为了提高工作在太赫兹波段偏振分束器的性能, 采用激光诱导与化学镀铜的方法在聚酰亚胺衬底上制作了亚波长周期金属线栅太赫兹偏振分束器, 并以返波振荡器作为太赫兹辐射源搭建了偏振分束特性测试系统。当入射波频率为340GHz、入射角为45°时, 测得在入射波偏振在0°～180°变化过程中, 该偏振分束器具有良好的偏振分束特性, 透射和反射的消光比分别为27.3dB和10.5dB, 插入损耗分别为0.13dB和0.32dB; 用太赫兹时域光谱系统测得偏振分束器在0.2THz～1.5THz频域内透射消光比大于18dB。结果表明, 测试结果与时域有限元方法模拟结果基本吻合。

In order to improve the performance of a terahertz polarizing beam splitter, a sub-wavelength period metal wire-grid terahertz polarizing beam splitter, based on a copper grating on polyimide(PI) substrate, was fabricated by the way of laser induced and non-electrolytic plating. The good polarization characteristics in the range of 0°~180° polarization angle were verified experimentally using backward wave oscillator at the fixed frequency of 340GHz at the incident angle of 45°, the extinction ratio of 27.3dB and 10.5dB as well as the insertion losses of 0.13dB and 0.32dB were measured for the transmitted and reflected beams, respectively. The broadband transmission of TM wave of the splitter was also measured by terahertz time-domain spectroscopy, and the extinction ratio larger than 18dB was obtained in the frequency range of 0.2THz~1.5THz. The experimental results are in good agreement with the simulation results by means of the finite element method.