Hi @AMV,

Depending on your end goal for the simulation, you can simulate evanescent waves to a certain extent with OpticStudio. This Knowledgebase article gives some good examples of frustrated total internal reflection (FTIR) that could apply to your wave guide model using coatings: Modeling frustrated total internal reflection in Non-Sequential mode. The simulations can allow you to see the evanescent effect on reflection as well as coupling into near-by objects.

The physics behind evanescent waves can be complicated, and because OpticStudio is not a FDTD electromagnetic solver, like Ansys Lumerical (see Evanescent waveguide couplers for an example), there will be limits on the granularity and field information you can extract. Assuming the waveguide is much larger than the wavelength of interest, OpticStudio is capable of modeling light propagation through the structure. However, it is important to note that OpticStudio is primarily a ray-based simulation, and therefore will have significant limits in modeling detailed wave behavior. It does have some features, like Physical Optics Propagation, that consider certain wave effects, but the FTIR and evanescent examples are using ray-based calculations.

Best,
Ethan