Reconstruction of the Near-Field Electric Field by SNOM Measurement

Yihang Fan, Xiaotian Xue, Fei Yang, Jianqiao Zhao, Xiaoyu Xiong, Jingbo Sun, Weipeng Wang, Ji Shi, Ji Zhou and Zhengjun Zhang

Nano Letters 23, 9900 (2023)

Scanning near-field optical microscope (SNOM) with nanoscale spatial resolution has been a powerful tool in studying the plasmonic properties of nano materials/structures. However, the quantification of the SNOM measurement remains a major challenge in the field due to the lack of reliable methodologies. We employed the point-dipole model to describe the tip–surface interaction upon laser illumination and theoretically derived the quantitative relationship between the measured results and the actual near-field electric field strength. Thus, we can experimentally reconstruct the near-field electric field through this theoretically calculated relationship. We also developed an experimental technique together with FEM simulation to get the above relationship experimentally and reconstruct the near-field electric field from the measurement by SNOM.