This video is taken from the FDTD Learning Track on Ansys Innovation Courses.
Transcript
The Material Database comes with many default materials, including Silicon, Glass, Air,
Gold and Silver.
Most materials are implemented using the materials.
Most materials use the sampled 3D data material model, which is based on experimental measurements
of the material refractive index.
The source of
the data is specified in the material name.
For example, Palik indicates the data is from the Handbook of Optical Constants of Solids
by Palik.
The Material Database also includes Perfect Electrical Conductor for 2D and 3D structures
and Etch for 3D structures.
Etch is a material with refractive index 1 by default with mesh order 1 and it is used
to effectively create cut outs in objects since the etch material will override other
materials that it overlaps.
The mesh order property of materials is used to determine which object gets priority when
two materials are overlapping in the same region.
More information about mesh order can be found in the link listed below this video.
A wide variety of material models are available.
You can see the full list by clicking the Add button.
The material models available include simple models like dielectric which lets you set
a constant real refractive index over wavelength, (n,k) Material which lets you set a real and
imaginary part of the refractive index for single frequency simulations, and Sellmeier
and Drude, or Lorentz materials which use equations to define the permittivity as a
function of frequency.
You can also add sampled data materials where you can import data over frequency or wavelength.
For sampled 3D materials, the data will be the refractive index or permittivity, and
for sampled 2D materials, the data will be the bulk conductivity or resisitivity of the
material and sheet thickness.
Sampled data can be used to load experimentally-measured material data in order to get simulation results
that closely resemble what you would get using the same experimental conditions.
There are also nonlinear materials that allow you to simulate gain materials and effects
like harmonic generation and optical bistability.
The default simulation settings are meant for simulating linear materials so if nonlinear
materials are used, the simulation will require careful setup.
There are tips for nonlinear simulation settings in the links below.
Conductive material models include the 2D conductive model which lets you specify the
bulk conductivity of the material and the sheet thickness, and the graphene model which
takes graphene material parameters such as scattering rate and chemical potential.
There is also an index perturbation model which lets you set up a refractive index that
varies as a function of carrier concentration or temperature.
See the later Advanced capabilities unit for more detail about this.
A full list of material models and the definitions of the parameters of those models can be found
in the online Knowledge Base in the related links below this video.
On the same pages you can also find additional material models such as a step index model
and two-level one-electron model that you can download.