基于H形狭缝孔对结构的太赫兹表面等离激元传播方向调控

Controlling Propagation Direction of Terahertz Surface Plasmons Based on H-shaped slit-pair Structures

表面等离激元由于其独特的场增强特性,在国内外引起了广泛的关注。采用亚波长金属狭缝谐振器激发表面等离激元是当前较为简便的表面等离激元激发方式。本文基于此激发方式,在太赫兹波段,从理论上设计了一种工作在圆偏振波入射下的H形金属狭缝孔对结构。通过改变纵向上相邻金属狭缝孔对之间的相对旋转角度和距离,进而改变H形金属狭缝孔对阵列激发表面等离激元的相位梯度,实现了对表面等离激元传播方向的控制。该结构为实现太赫兹表面等离激元传输调控器件提供了一种新的设计途径。

Surface plasmons have attracted broad attention around the world due to their unique field enhancement properties.Currently,one convenient method to excite surface plasmons is to use subwavelength slit resonators.Based on this,an H-shaped metallic slit-pair structure is numerically designed in the terahertz band,which works for circularly polarized incidence.By varying the relative rotation angle and distance between neighbouring slit-pairs in the longitudinal direction,the phase gradient of the surface plasmons excited by the H-shaped metallic slit-pair array can be controlled,thus allowing the control of the propagation direction of the surface plasmons.The proposed structure provides a new design approach in implementing terahertz surface plasmon devices for propagation control.