有限厚度传导孔径对太赫兹脉冲的时空整形

摘要

Terahertz (THz) pulses after spatiotemporal shaping have been widely applied to THz spectroscopy and imaging.We simulate the shaping effect of rectangular and circular apertures by employing the three-dimensional (3D) finite-difference-time-domain (FDTD) method.The simulation results show that we can realize effective shaping and filtering of THz pulses using rectangular and circular conductive apertures of finite thickness.When the long side of the rectangular aperture is perpendicular to the polarization direction of the incident wave,the rectangular aperture has a good influence on the shaping and filtering of THz pulses.However,when the long side of the rectangular aperture is parallel to the polarization direction of the incident wave,it almost has no obvious effect on the shaping and filtering of THz pulses.The circular aperture has more obvious effect on shaping of THz pulses than the rectangular aperture.Moreover,these simulation results can be interpreted qualitatively by the theory of planar waveguides.%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.