太赫兹宽带消色差偏折器设计

Terahertz broadband achromatic deflector design

偏折器可以调控电磁波的传播方向,在传感、光通信等领域具有重要的地位,但是色差问题使传统偏折器的偏折方向随波长变化,很大程度上限制了偏折器的发展。为了消除偏折器中的色差问题,通过对太赫兹偏折中色差问题的物理机理进行分析,采用几何相位与共振相位结合的设计方法,在全介质超表面上实现宽带消色差偏折的功能。利用有限时域差分法(FDTD)在0.5 THz到1.1 THz的宽带范围内仿真验证设计的方法并实现了超表面消色差偏折的效果。

The deflector obtains the directional propagation of electromagnetic wave, and plays an important role in sensing and optical communication. The chromatic problem causes the deflection angle varying with wavelength, which limits the application scope of the deflector. In order to achieve achromatic aberration, in this paper, we analyze the physical mechanism of the chromatic aberration and realize achromatic terahertz deflectors using the geometric and resonant compensation phase, which are composed by the all-dielectric metasurface. In addition, the simulations of the achromatic effect are carried out by the finite difference time domain(FDTD)method within a continue frequency range from 0.5 to 1.1 THz.