Fig. 1. Grid discretization method and local electric field magnetic distribution of gold nanosphere dimer. (a) Dispersion of fine and uniform grid; (b) sub-grid dispersion

Fig. 2. Boundary transition diagram of coarse and uniform grid and sub-grid

Fig. 3. Electromagnetic field distribution and K-means clustering result of interaction between gold nanosphere disk aggregates and electromagnetic field. (a) Electromagnetic field distribution of gold nanosphere disk array in range of 3 μm; (b) clustering of three electric field data by K-means clustering

Fig. 4. Relationship between among average enhancement factors AEF 1 and AEF 2 of gold nanosphere dimer, and spacing

Fig. 5. Relationship between among average enhancement factors AEF 1 and AEF 2 of gold nanospheres, and number of gold nanoparticles

Fig. 6. Relationship between among average enhancement factors AEF 1 and AEF 2 of disk aggregates of gold nanospheres with diameters of 3 μm, and spacing of nanoparticles