Learning Forum

[Rosmin_Elsa_Mohan]

hexagonal boron nitride as a material for Lumerical simulations - can this be added with object defined RI? Saw some forums previously on KX- but now seems missing after the migration. Appreciate any help. n

[Greg Baethge]

Hi Array,
Thank you for posting your question. I'm not too familiar with this material, but this seems to be more like a 2D material (similar to graphene). In this case, using a 2D conductivity approach should be better. You can either use a conductive 2D material (you need to specify the bulk conductivity and the thickness of the layer) or a sample 2D data material, where you have a table of the conductivity as function of the wavelength/frequency (see Standard optical conductivity material models in FDTD and MODE).
Then the layer of hBN can be added using a 2D rectangle or a 2D polygon. The simulation settings will be similar to the one used for graphene.
Let us know if you have any question.

[Rosmin_Elsa_Mohan]

Thanks Greg for the reply.
Can i check if graphene/hBN may be imported as a sample 3D material using (n,k) values versus wavelength ?
For the 2D models that you suggested, we need to key in the refractive index , am i right?

Thanks again,
Rosmin

[Greg Baethge]

Hi Rosmin,

You can use a sample 3D material for graphene/hBN, however, this means using a volumetric approach where a 3D object is used with the material, as in the C (graphene) - Falkovsky (mid-IR) material model example. Here, we calculate a 3D permittivity from the surface conductivity of Graphene, setting an artificial thickness of the layer (Delta):

Delta will be the thickness of the object in the simulation. The downside of this model, it requires a fine mesh over the Graphene object to resolve its thickness (default value is Delta=1nm). That's why we prefer the 2D material models, that involve importing the bulk conductivity (in S/m) vs lambda/frequency. Note it is possible to create such 2D conductivity data from the permittivity as shown in this example.