Hello Lumerical community,
I’m trying to perform basic simulations but I have some trouble to do so.
What I want: to study rear interface of an optical device. For example, what is the reflectance between CIGS and Molybdenum and how to improve it.
So, basically, the refelctance between CIGS and molybdenum is easily computed by Fresnel coef. or by using a transfer matrix method. The problem appears when I add some dielectric between them to improve the amount of light reflected in the CIGS (the idea is obviously to reflect large wavelength back to the CIGS layer).
Fresnel doesn’t take into account the interferences in the dielectric layer due to multi-reflection within the layer. So, it supposes to work very well with transfer matrix, but it is not. In some case, I got Reflectance higher than 1 (or 100%) which is not correct. So I compared my results with Lumerical simulation. If my incident material is transparent, I got the same results with FDTD or transfer matrix. When the incident material is absorbing, I got wrong results with transfer matrix, and with FDTD… there is a problem, and I don’t know how to solve it.
As the incident material is absorbing, it will decrease the light source irradiance while the plane wave propagates toward the interface. I’m a little bite lost here. As I have to put the source in the absorbing medium, I try to put it really next to the interface (like 20 nm from it). Then I have to put the monitor (power) just a little bite far from the source in order to record the Reflectance. But then, the input wave is already a little bite absorbed before reaching the interface and the monitor.
Can I do that with Lumerical ? If someone also knows why transfer matrix failed when the inner material is absorbing, that could also be great.