Surface phonon polaritons (SPhPs) are potentially very attractive for subwavelength control and manipulation of light at the infrared to terahertz wavelengths. Probing their propagation behavior in nanostructures is crucial to guide rational device design. Here, aided by monochromatic scanning transmission electron microscopy-electron energy loss spectroscopy technique, we measure the dispersion relation of SPhPs in individual SiC nanorods and reveal the effects of size and shape. We find that the SPhPs can be modulated by the geometric shape and size of SiC nanorods. The energy of SPhPs shows red-shift with decreasing radius and the surface optical phonon is mainly concentrated on the surface with large radius. Therefore, the fields can be precisely confined in specific positions by varying the size of the nanorod, allowing effective tuning at nanometer scale. The findings of this work are in agreement with dielectric response theory and numerical simulation, and provide novel strategies for manipulating light in polar dielectrics through shape and size control, enabling the design of novel nanoscale phonon-photonic devices.

表面声子极化激元 (SPhP) 对于红外到太赫兹波长的亚波长控制和光操纵具有潜在的吸引力。探索它们在纳米结构中的传播行为对于指导合理的设备设计至关重要。在这里，借助单色扫描透射电子显微镜-电子能量损失光谱技术，我们测量了单个 SiC 纳米棒中 SPhP 的色散关系，并揭示了尺寸和形状的影响。我们发现 SPhPs 可以通过 SiC 纳米棒的几何形状和尺寸进行调制。SPhPs 的能量随着半径的减小而发生红移，表面光学声子主要集中在半径较大的表面。因此，可以通过改变纳米棒的大小将场精确地限制在特定位置，允许在纳米尺度上进行有效调整。这项工作的发现与介电响应理论和数值模拟一致，并为通过形状和尺寸控制在极性电介质中操纵光提供了新的策略，从而实现了新型纳米级声子光子器件的设计。