Table 1 Parameters in the FEM simulations.

plasma frequency of Ag, \(\:{\omega\:}_{p}\)

2.321 PHz

30

damping frequency of Ag, \(\:\gamma\:\)

5.513 THz

30

Refractive index of air, \(\:{n}_{\text{a}\text{i}\text{r}}\)

1

-

Refractive index of Si, \(\:{n}_{\text{S}\text{i}}\)

3.41

31

Refractive index of Al₂O₃, \(\:{n}_{{\text{A}\text{l}}_{2}{\text{O}}_{3}}\)

2.35

28