Functions with imaginary parts

Dzmitry

Hi everybody!

I'm a newcomer to working with COMSOL and I've recently encountered a problem. I need to define the complex refractive index value of a material as a function of wavelength in the form of N = n - i*k, where n and k are the functions of wavelength (lambda0_rfweh). Whatever I do, every time I start to solve (after meshing of course) it gives me an error saying the software is not able to evaluate my function N. I tried to define N as a function and N as an equation in the subdomain equations, as well as global expressions and scalar ones, and no result. Thanks in advance!