In this paper, we present the design, simulation, fabrication and characterization of a terahertz (THz) filter based on metamaterial consisting of the periodical double symmetric splits ring resonator (DS-SRR) array. We can observe that the metamaterial-based filter possesses a band-pass transmission when the electrical field is along y direction, and it possesses a low-pass transmission when the electrical field is along x direction. Our results demonstrate that the proposed filter can realize the switching between band-pass effect and low-pass effect by only changing the polarization direction of the incident electromagnetic wave. Moreover, the calculated surface current distributions are also used to analyze the switchable mechanism of the THz metamatrial filter. Therefore, the proposed THz wave filter has a potential application in THz wave communication systems.

太赫兹时域光谱仪的测量速度是一个非常重要的指标, 为了提高光谱仪的测量速度需要提高延迟线的扫描速度。 实验研究了扫描速度、 时间常数、 采样率对太赫兹时域光谱仪信号品质的影响。 研究结果表明, 当时间常数为10 ms时, 提高扫描速度不会对信号幅度造成较大改变; 而当时间常数为30, 100和300 ms时, 随着扫描速度的提高, 信号幅度会迅速降低, 且时间常数越大信号幅度衰减越快, 因此, 为了避免在提高测量速度时导致信号品质的劣化, 应尽量设置较小的时间常数。 另一方面, 当采集一定时域长度的信号时, 扫描速度越高, 采集到的采样点数越少, 时域波形失真越严重, 因此在提高扫描速度时, 不仅需要减小锁相放大器时间常数, 同时还需要相应的提高采样率以避免因采集点数减少而造成信号波形的失真。 该结果可为提高太赫兹时域光谱仪的测量速度提供参考。