一种光激发可切换的双频太赫兹超材料吸收器

提出了一种基于方环-金属线结构的光激发动态可切换双频太赫兹超材料吸收器。通过调节嵌入在结构间隙中的光敏硅和锗的绝缘/导通状态,该吸收器可在不改变结构的前提下在三个双频完美吸收态之间自由切换。结果表明:当没有光泵浦时,该吸收器工作在0.987 THz和1.767 THz双频吸收态;当采用800 nm激光泵浦时,该吸收器可切换为0.717 THz和1.444 THz处的双频吸收;当采用1550 nm激光泵浦时,该吸收器的吸收状态可切换为0.716 THz和1.767 THz处的双频吸收。本文从等效电路、匹配阻抗和电流分布三方面解释了三种可切换的双频吸收机制,并讨论了极化不敏感的吸收特性。

Light-Excited and Switchable Dual-Band Terahertz Metamaterial Absorber

In this paper,we propose a light-excited,dynamically switchable,dual-band terahertz metamaterial absorber based on a square ring-wire structure.By adjusting the insulation/conduction state of photosensitive silicon and germanium chips embedded in the gaps of the structure,the absorber can be switched freely between three dual-band perfect-absorption states without changing its structure.The results show that when there is no laser pumping,the absorber works in a dual-band absorption state at 0.987 THz and 1.767 THz;when using 800 nm laser pumping,it switches to dual-band absorption at 0.717 THz and 1.444 THz;and when using 1550 nm laser pumping,it switches to dual-band absorption at 0.716 THz and 1.767 THz.In addition,the three switchable dual-band absorption mechanism is explained from equivalent circuit,impedance matching and current distributions,and the polarization-insensitive absorption characteristics are discussed.