基于表面等离子体的太赫兹光束方向调控的模拟研究

Simulation research on the control of terahertz beam direction by surface plasmon

本文根据锑化铟(InSb)材料在THz波段下复介电常数对温度的响应特性,采用了带有光栅的锑化铟-介质-锑化铟的表面等离子体波导结构,实现了1THz频率光束的准直出射,并能够通过调整结构两侧光栅的温度差来控制出射光束的角度.由时域有限差分方法得到光束偏转角度与温度差之间的关系.理论上利用表面等离子体波导模式的光栅耦合机理解释光束方向改变的原因.

Based on the temperature-dependent complex dielectric constant of indium antimonide,an InSb-dielectric-InSb plasmonic waveguide structure with the grating was realized. At the frequency of 1 THz,a directional beam was obtained, and its radiation direction can be controlled by changing the temperature difference between the grating structures on each side. Finite difference time domain （FDTD） method was adopted to evaluate the relationship between the off-axis angle of the beam and the temperature difference. The tunable directional beaming can be attributed to the grating coupling of the TM surface modes in plasmonic waveguides.