High-performance THz polarizers, as a quasi-optical device to manipulate THz waves, are highly demanded for THz spectroscopy and imaging applications. In this work, we have employed the femtosecond laser micro-machining technique to fabricate freestanding THz wire grid polarizers with two kinds of reinforced line structures which weaken the effects of gravity sagging and entanglement of long free wires, thus enabling large-scale processing. The effect of the reinforced lines on the polarizers were simulated by the Finite-Difference Time-Domain (FDTD) method, and the performances of the polarizer were characterized by THz time-domain spectroscopy and compared with that of a commercial wire gird polarizer. The calculated transmittance is in good agreement with the FDTD results. The degree of polarization and the extinction ratio of the polarizer with discontinuous reinforced lines are better than those of a commercial wire grid polarizer.

高性能太赫兹偏振器，作为操纵太赫兹波的准光学设备，对太赫兹光谱和成像应用提出了很高的要求。在这项工作中，我们采用飞秒激光微加工技术来制造具有两种增强线结构的独立式太赫兹线栅偏光片，从而减弱了重力下垂和长自由线缠结的影响，从而实现了大规模加工。通过有限差分时域（FDTD）方法模拟了增强线对偏振器的影响，并通过THz时域光谱表征了偏振器的性能，并与商用线栅偏振器进行了比较。计算出的透射率与FDTD结果非常吻合。