Photonics

Photonics

Anisotropic and Complex Permittivity and Permeability

    • amnonjw
      Subscriber

      Hello Lumerical team.

      To better understand PML, I'm trying to implement Anisotropic PML regions, based on papers by like Kosihba et al (that used them for Photonic Crystal waveguide), Sacks et al, Wu et al. It appears I need to define a medium for which:

      • the permittivity is anisotropic in real and imaginary parts

      and

      • the permeability is anisotropic in real and imaginary parts

      I'd also need to define some of the tensor components with dependence on frequency, but for a source with narrowband spectrum I think I can manage a material without dispersion.


      I see that the Material Explorer can define different types of material but not what I require:

      * (n,k) material can have anisotropic permittivity both real and imaginary parts, but the permeability is as in vacuum.

      * Paramagnetic materials that have anisotropic permittivity and permeability, but their imaginary part is 0

      * Magnetic Electric Lorentz materials with real and imaginary permittivity and permeability, but they are isotropic


      Is there something I'm missing in the Material Explorer that can be used for my requirements?

    • Guilin Sun
      Ansys Employee
      Are you trying to develop your own PML or want to use Lumerical's PML?
      If it is the latter, you do not need to define them. What you can do is to modify the PML material data.
      If you are developing your own PML for your own FDTD, it is up to you. However you cannot add your own PML to Lumerical products.
      If you apply such material to a geometry, you can use this model: https://support.lumerical.com/hc/en-us/articles/360034394734-Advanced-and-custom-optical-material-models-in-FDTD-and-MODE Then you have to figure out the parameters in the model from your data.

    • amnonjw
      Subscriber
      Hi gsun To clarify, I'm not developing a separate code for FDTD. I'm sure of the capabilities of Lumerical's FDTD and I wish to use it for my simulations.
      At the same time I follow your advices on the other thread for Photonic Crystal waveguides and boundary conditions, I read about the theory behind PML layers, and I found the paper byKosihba et al where they use anisotropic PML for Photonic Crystal structures and got results better than the conventional PML layers (as in the work from Berenger et al. that is refenced on the page explaining Lumerical's PML).
      I read the page that you linked to in your reply, but I missed the beginning where it referenced Flexible Material Plugin. I will learn more about this.
    • Guilin Sun
      Ansys Employee
      There are hundreds of papers regarding to PML. You do not need to follow theirs, but by modifying PML parameters you should be able to get better performance. Please read
      Ansys Insight: Choosing the most appropriate profile for PML boundary conditions
      PML boundary conditions in FDTD and MODE
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