The surface plasmon polaritons (SPPs) have been demonstrated with significant advantages in nano-photonic devices due to their ability to control and manipulate light. In this paper, the transmission characteristics of light and field properties of SPPs on the surface of different shapes of gratings in Kretschmann–Raether configurations are studied. With increase of frequency, the strength of SPPs and the light-SPP conversion efficiency decrease, and the conversion efficiency of grating is lower than that of the smooth gold film. The minimum reflection spectrum is obtained through connecting the minimum reflection coefficients corresponding to different incident angles. The valley points of the minimum reflection spectrums are close in gratings with different width while quite different in gratings with different groove depths, which means that the depth of the grooves in grating can regulate the maximum transmission frequency of light. The effective plasma frequency of metal grating is proposed to replace the plasma frequency of the gold film, which shows that the groove depth is negatively relevant to effective plasma frequency of the gold grating and the frequency of SPPs while the groove width does not affect them. Synthesizing the simulation results, we found that the effective plasma frequency of gold grating and dispersion relations of SPPs on the surface of grating change with the propagation trajectory of SPPs. The physical mechanism of this phenomenon is explained through an analogy of the surface wave on grating to slow wave in slow-wave-structure of vacuum electronic devices.

表面等离子体激元 (SPP) 已被证明在纳米光子器件中具有显着优势，因为它们具有控制和操纵光的能力。本文研究了 SPPs 在 Kretschmann-Raether 配置的不同形状光栅表面上的光和场特性的传输特性。随着频率的增加，SPPs的强度和光-SPP转换效率降低，光栅的转换效率低于光滑金膜的转换效率。通过连接不同入射角对应的最小反射系数得到最小反射光谱。不同宽度光栅的最小反射光谱谷点相近，而不同凹槽深度的光栅差异较大，这意味着光栅中凹槽的深度可以调节光的最大传输频率。提出了金属光栅的有效等离子体频率来代替金膜的等离子体频率，这表明凹槽深度与金光栅的有效等离子体频率和SPP的频率呈负相关，而凹槽宽度对它们没有影响。综合仿真结果，我们发现金光栅的有效等离子体频率和光栅表面SPPs的色散关系随着SPPs的传播轨迹而变化。这种现象的物理机制是通过将光栅上的表面波类比为真空电子器件慢波结构中的慢波来解释的。