We wish to analyze the efficacy of plasmonic nanoparticles placed within the Si substrate. For this, should we design the simulation as such: place a layer of the substrate, place the layer of particles of it, and then place the final layer of substrate over the particle layer? Or can we etch the inner layer of the substrate to create spaces to place the particles in?
If the plasmonic nanoparticles are embedded in the Si substrate, you can account this by giving a mesh order of 1 for the plasmonic material. The silicon will have a mesh order of 2. This ensures that the plasmonic particle is embedded in the matrix of silicon. You can select the mesh order for each component by going to the material tab and selecting override mesh order from material database.
Always, recheck the whether the structure is right with the help of a refractive index monitor to ensure that you have achieved the structure you have desired.
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Thanks for the quick response. How do I embed the particles? Do I simple place them inside the Si cell substrate?
You can place them inside the Si, and by giving the plasmonic nanoparticles a mesh order of 1, Lumerical FDTD solutions ensures that volume is represented by the dielectric constant of the metal and not that of silicon. Just ensure the mesh order of silicon is 2.
You may find this KB page useful: Mesh order (optical). It explains how the mesh order works in the optical solvers.