Learning Forum

[bublee-2016114988]

Where should the slab mode position be in this? In the Au nanoparticle region or the ring region?

[jev1]

Hey @bublee,

You should put it in the waveguide, any one waveguide. Putting it in nanoparticle would assume a vertical solution for your waveguides that is that of the gold and not your silicon region.

You will end up with the Au NP affecting only the 2D solution of your system, which is not correct (since the full 3D mode is affected by the presence of the particle, especially if it is small and then you have plasmonic resonances), but will give you a fair approximation.  If your ring is not very large I suggest using 3D FDTD, or if its large simulating the couplers independently, and a small waveguide section with a single Au NP, and then using interconnect to build  ring models using said models.

Best, Juan

[bublee-2016114988]

Thank you very much, Juan.

[Guilin Sun]

Thank you for your reply.

It seems you are using varFDTD? As the above answered, usually it is not a good idea to approximate the nano particle which in most cases a sphere to be 2D.

VarFDTD approximates the 2D mode into two 1D modes: z slab and y slab. All other places will need to use this z-slab mode to get the effective material parameters. Therefore the rerence green point is important to be in the waveguide core.

The buswaveguides are used to couple injection light into the ring and couple out, and the particle seems to pertubate the resonance. So both regions are critical for coupling. Override meshes are needed there.