金属双柱metamaterial负折射特性的液晶调控

Tunablility of Negative-Refraction in Metal-Rod Pair Metamaterial by Liquid Crystals

本文研究了金属双柱metamaterial对太赫兹波负折射的液晶调控。结果表明,当液晶的介电系数从2逐渐增大到4,产生负折射的频率从0.648 THz逐渐变化到0.413 THz,包含了0.650 THz和0.500THz附近两个大气窗口;通过改变液晶的介电常数,可以在该频段内任一频点实现负折射、零折射或正折射。由于液晶的介电常数可以通过外加交流偏压或光场进行调控,因此利用液晶可以实现对太赫兹波负折射频率和传播方向的调控。

Tunahlility of negative-refraction in metal-rod pair metamaterial by liquid crystals is demonstrated by numerical simulation. It is shown that negative index can be achieved in the frequency range from 0. 648 THz to 0. 413 THz, covering two atmospheric windows around 0.65 THz and 0.50 THz, by tuning the permittivity of liquid crystals from 2 to 4. Negative, zero or positive index can be obtained at any frequency within the negative refraction range by changing the permittivity of liquid crystals. Since the permittivity of liquid crystals can be tuned by an external bias or a light field, the frequency of negative refraction and the propagating direction of a THz wave can be well controlled.