在十字型太赫兹带通滤波器的时域有限差分法仿真中,随着铝箔厚度增大,主峰变窄,且高频处出现多个异常透射峰。利用飞秒激光微加工技术制备出铝箔厚度为150 μm的太赫兹滤波器,并利用时域太赫兹光谱系统进行性能测试。结果表明:实验结果与时域有限差分法模拟结果基本吻合;异常透射峰源于十字结构狭缝侧壁上的表面等离子体波的法布里-珀罗共振耦合,这种耦合效应可用于控制表面等离子体波,制造新型太赫兹器件。

In the simulation of cross-type terahertz bandpass filter by using the finite-difference time-domain method, the main peaks narrow as the thickness of the Al foil increases, and several abnormal transmission peaks appear at high frequencies. A terahertz filter with Al foil thickness of 150 μm is fabricated by femtosecond laser micro-machining; it is tested using a time-domain terahertz spectroscopy system. The results show that the experimental results are consistent with the finite-difference time-domain method simulation results. The anomalous transmission peaks result from the Fabry-Perot resonant coupling of the surface plasmon polariton waves on the sidewalls of the slits of the cross structure. This coupling effect may be useful in controlling surface plasmon polariton waves and fabricating new terahertz devices.