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太赫兹脉冲经时空整形后常被用在太赫兹光谱和成像上。用三维时域有限差分法模拟了矩形和圆形孔径的整形效应,模拟结果表明有限厚度矩形和圆形孔径对太赫兹脉冲能实现有效的整形和滤波。当矩形孔径长边垂直于入射波的偏振方向时,矩形孔径有较好的整形和滤波作用,当矩形孔径长边平行于入射波的偏振方向时,几乎没有明显的整形和滤波作用。圆形孔径具有比矩形孔径更加显著的整形和滤波作用。这些模拟结果用平面光波导理论可以得到很好的解释。
Terahertz pulses are often used in terahertz spectroscopy and imaging after temporal and spatial shaping. The three-dimensional finite difference time-domain method is used to simulate the shaping effect of rectangular and circular apertures. The simulation results show that finite thickness rectangular and circular apertures can effectively shape and filter terahertz pulses. When the long side of the rectangular aperture is perpendicular to the polarization direction of the incident wave, the rectangular aperture has better shaping and filtering effects. When the long side of the rectangular aperture is parallel to the polarization direction of the incident wave, there is almost no obvious shaping and filtering effect. Circular apertures have more significant shaping and filtering effects than rectangular apertures. These simulation results are well explained by the theory of planar lightwaves.