Discussion Forum

HI!

I'm trying to model the light transmission from a source located between two dielectric mirrors. The attached figure shows the structure that consists in a multilayered structure with three different materials. The light souce is in the pink layer.

In order to introduce the light, I have created a boundary in the middle of the emissor (that's why there is a black line therein), and assigned an user-defined port to the boundary. In addition, I have checked the "Activate slit condition on interior port".

The problem arise when choosing the slit type. Let us suppose that the light is emmited from left to right in the port and "PEC-backed" slit type is chosen. In that case, the light is refracted and reflected in the rightmost structure; the problem arise when the reflected light reaches the port, as the latter prevents the light to propagate from right to left at the left of the port. This is not the expected behaviour of the light. For this reason, I chose "domain-backed" slit type, which allows the light to cross the port.

The problem with chosing "domain-backed" slit type is that the scattering matrix coefficients give absurde values. For instance, if we denote 1 as the port at the emissor and 2 and 3 to the ports at the left and the right of the structure, respectively, at a given value of the wavelength a get values as abs(S21)^2=39, abs(S31)^2=8 and abs(S11)^2=2289. I suppose that this could be cause by a discontinuity in the x component of the Poynting vector.

My question is: having in mind the drawbacks presented above, how can one calculate the transmittance of the light emitted from the light source to the left/right interfaces of the multilayered structures of the present problem?

Many thanks in advance.