A lot of identical staff in Comsol material database?

Question

I got a lot of elements in Material Browser of Comsol Multiphysics of Optics section. Unfortunately, all data looks identical and similar to stub.

Each element has the same expression, which can be seen on screenshot.

How this should be used?

Answer 1

I don't see anything unusual here. You have a material property that is defined in terms of other material properties.

In your particular case, the real and imaginary parts of the refractive index are functions defined from n_interp and k_interp, which usually denote the interpolated values (either supplied by COMSOL or user-supplied). In many simulations, you might need the refractive index to be a continuous (and maybe even differentiable function); thus, some modeling from a discrete material properties data is needed. The underlying sampled data (n_interp and k_interp) is likely different and comes from different sources for different materials.

Moreover, I would assume, that for some materials+data combinations, the actual functional dependence might be slightly different (in additiona to the differences in the sampled properties before interpolation); however, that is an educated guess based on properties (other than the refractive index) that I had past experience in.

Now, you might be interested in how to set up your own refractive index properties, and there are several things you can do:

• supply your own sampled data (this might be not a bad example)
• change the expression of how you calculate the refractive index, which might be useful if you are investigating some custom materials' models or metamaterials.