In the simulations you have to set properly the optical properties of the silver nanoparticles. At that wavelength the silver can be described with a complex value of the permittivity, with real and imaginary part (see [1]). You can model the silver as dielectrics characterized from a refractive index and an exctiction coefficient (you can find the values here [2,3]).
You have also to consider that the LSPR will be dependent from the polarization of the incoming wave.
1. P.B. Johnson and R.W. Christy, “Optical Constants of the Noble Metals,” Phys. Rev. B, vol. 6, pp. 4370−4379, 1972.
However, I have been focusing on near-field enhancement of electric field around 40 nm sized Ag NPs. I have developed the simulation with Lumerical FDTD software.
The software itself give the dielectric properties of Ag.
I don't know my simulation results are right. How can I check it is right or not?
Most of the journal papers gave the near-field profile only for Gold nanoparticles not for Silver nanoparticles. Why it is so?
It's never easy to understand if the results are right.
You should find a work where something similar to your study has been done reproduce exactly what they have done (better if you find more works). If the results are the same then it means that your simulations have been set properly. You can also start from some study on Au nanoparticles and then just change the material. Anyway my suggestion is always to check how the simulator model a material (sometimes they use a constant refractive index). sincerely I don't know why gold NP have been studied more than Ag NP, probably just because they are more used for optical experimental devices.
Shamjid Palappra Can you share your file, so that i can also learn from your development, am totally new in this field, I want to know how to start. Thank You