Waveguide filter with nanodisk resonators


I am a new user, and need to simulate a paper’s work with lumerical FDTD. I have been trying to learn from the support section, but I am stucked. Could you please look at my file and tell me if I am on the path or doing something wrong? Additionally, the paper is < Tunable band-pass plasmonic waveguide filters with nanodisk resonators >. I couldn’t figure out if they did it in 2D or 3D. If 3D what is the thickness of the Silver(?) They mentioned as semi infinite, but I have no idea how can I put this semi-infinite information to the software. If someone gives me heads up on this project, I would be glad. Thanks in advance.project_nano_class.fsp (263.4 KB)

Hi @y.yildirim

just by looking at plots in the paper, it seems like they did a 2D simulations (which any ways will be a good starting point). Here are the modifications that you can do:

a) expand your FDTD region and rectangle size. Also extend your rectangle (silver plates) to extend through PML as they are semi-infinite. Also adjust the mesh size and use mesh override so that your mesh overlaps with the edge of your objects. Here is a good place to learn about setting up your simulation file.

b) select 2D in your simulations rather than 3D
c) you can build the geometry using rectangles and disks and using mesh order. To makes sure that you set them correctly, you can use an index monitor to look at the index profile of your simulation region.

Please do these modification and run the simulations. We can employ convergence testing to make sure that results are reasonable later on.

Please keep me updated of your results and I’ll be more than happy to look at your modified file.

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Hello @bkhanaliloo

Thank you so much for your help. I did your suggestions, but the results are shown weird. I think, the mesh I used is not proper. Additionally, how am I going to get Transmission vs wavelength graphs?
Nanodisc_waveguide_2D.fsp (1.6 MB)


Hi @y.yildirim

I realized that you were using 2D rectangles in your simulations. Please note that we use FDTD to set simulations to 2D and we leave devices on 3D.

I have modified your simulation file and could capture the plasmonic modes at ~520 nm and 820 nm. Please see plots below:

I recommend you to start with our getting starting examples to learn more about the proper settings of simulations and how to use different source and monitors. Please also note that mesh overrides needs to be set properly. For example, in your simulation, I set them such that I have a better resolution on the gap, and on rectangles for high resolution mode source. You can add another mesh override on microdisk and run the simulations to see how the results change.

I also have attached the transmission plots for you. The ripples are the result of non-decaying fields that happen with plasmonic simulations:

Here is my simulation file for your reference: Nanodisc_waveguide_2D_modified.fsp (320.7 KB)

I hope this was helpful.

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